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android / platform / external / tesseract / f8d326e45038968a99db48306ecd083f08dd65e3 / . / liblept / adaptmap.c
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/*====================================================================*
- Copyright (C) 2001 Leptonica. All rights reserved.
- This software is distributed in the hope that it will be
- useful, but with NO WARRANTY OF ANY KIND.
- No author or distributor accepts responsibility to anyone for the
- consequences of using this software, or for whether it serves any
- particular purpose or works at all, unless he or she says so in
- writing. Everyone is granted permission to copy, modify and
- redistribute this source code, for commercial or non-commercial
- purposes, with the following restrictions: (1) the origin of this
- source code must not be misrepresented; (2) modified versions must
- be plainly marked as such; and (3) this notice may not be removed
- or altered from any source or modified source distribution.
*====================================================================*/
/*
* adaptmap.c
*
* ===================================================================
* Image binarization algorithms are found in:
* grayquant.c: standard, simple, general grayscale quantization
* adaptmap.c: local adaptive; mostly gray-to-gray in preparation
* for binarization
* binarize.c: special binarization methods, locally adaptive.
* ===================================================================
*
* Adaptive background normalization (top-level functions)
* PIX *pixBackgroundNormSimple() 8 and 32 bpp
* PIX *pixBackgroundNorm() 8 and 32 bpp
* PIX *pixBackgroundNormMorph() 8 and 32 bpp
*
* Arrays of inverted background values for normalization (16 bpp)
* l_int32 pixBackgroundNormGrayArray() 8 bpp input
* l_int32 pixBackgroundNormRGBArrays() 32 bpp input
* l_int32 pixBackgroundNormGrayArrayMorph() 8 bpp input
* l_int32 pixBackgroundNormRGBArraysMorph() 32 bpp input
*
* Measurement of local background
* l_int32 pixGetBackgroundGrayMap() 8 bpp
* l_int32 pixGetBackgroundRGBMap() 32 bpp
* l_int32 pixGetBackgroundGrayMapMorph() 8 bpp
* l_int32 pixGetBackgroundRGBMapMorph() 32 bpp
* l_int32 pixFillMapHoles()
* PIX *pixExtendByReplication() 8 bpp
* l_int32 pixSmoothConnectedRegions() 8 bpp
*
* Measurement of local foreground
* l_int32 pixGetForegroundGrayMap() 8 bpp
*
* Generate inverted background map for each component
* PIX *pixGetInvBackgroundMap() 16 bpp
*
* Apply inverse background map to image
* PIX *pixApplyInvBackgroundGrayMap() 8 bpp
* PIX *pixApplyInvBackgroundRGBMap() 32 bpp
*
* Apply variable map
* PIX *pixApplyVariableGrayMap() 8 bpp
*
* Non-adaptive (global) mapping
* PIX *pixGlobalNormRGB() 32 bpp or cmapped
* PIX *pixGlobalNormNoSatRGB() 32 bpp
*
* Adaptive threshold spread normalization
* l_int32 pixThresholdSpreadNorm() 8 bpp
*
* Adaptive background normalization (flexible adaptaption)
* PIX *pixBackgroundNormFlex() 8 bpp
*
* Adaptive contrast normalization
* PIX *pixContrastNorm() 8 bpp
* l_int32 pixMinMaxTiles()
* l_int32 pixSetLowContrast()
* PIX *pixLinearTRCTiled()
* static l_int32 *iaaGetLinearTRC()
*
* Background normalization is done by generating a reduced map (or set
* of maps) representing the estimated background value of the
* input image, and using this to shift the pixel values so that
* this background value is set to some constant value.
*
* Specifically, normalization has 3 steps:
* (1) Generate a background map at a reduced scale.
* (2) Make the array of inverted background values by inverting
* the map. The result is an array of local multiplicative factors.
* (3) Apply this inverse background map to the image
*
* The inverse background arrays can be generated in two different ways here:
* (1) Remove the 'foreground' pixels and average over the remaining
* pixels in each tile. Propagate values into tiles where
* values have not been assigned, either because there was not
* enough background in the tile or because the tile is covered
* by a foreground region described by an image mask.
* After the background map is made, the inverse map is generated by
* smoothing over some number of adjacent tiles
* (block convolution) and then inverting.
* (2) Remove the foreground pixels using a morphological closing
* on a subsampled version of the image. Propagate values
* into pixels covered by an optional image mask. Invert the
* background map without preconditioning by convolutional smoothing.
*
* Note: Several of these functions make an implicit assumption about RGB
* component ordering.
*
* Other methods for adaptively normalizing the image are also given here.
*
* (1) pixThresholdSpreadNorm() computes a local threshold over the image
* and normalizes the input pixel values so that this computed threshold
* is a constant across the entire image.
*
* (2) pixContrastNorm() computes and applies a local TRC so that the
* local dynamic range is expanded to the full 8 bits, where the
* darkest pixels are mapped to 0 and the lightest to 255. This is
* useful for improving the appearance of pages with very light
* foreground or very dark background, and where the local TRC
* function doesn't change rapidly with position.
*/
#include <stdio.h>
#include <stdlib.h>
#include "allheaders.h"
/* Default input parameters for pixBackgroundNormSimple()
* Note:
* (1) mincount must never exceed the tile area (width * height)
* (2) bgval must be sufficiently below 255 to avoid accidental
* saturation; otherwise it should be large to avoid
* shrinking the dynamic range
* (3) results should otherwise not be sensitive to these values
*/
static const l_int32 DEFAULT_TILE_WIDTH = 10;
static const l_int32 DEFAULT_TILE_HEIGHT = 15;
static const l_int32 DEFAULT_FG_THRESHOLD = 60;
static const l_int32 DEFAULT_MIN_COUNT = 40;
static const l_int32 DEFAULT_BG_VAL = 200;
static const l_int32 DEFAULT_X_SMOOTH_SIZE = 2;
static const l_int32 DEFAULT_Y_SMOOTH_SIZE = 1;
static l_int32 *iaaGetLinearTRC(l_int32 **iaa, l_int32 diff);
#ifndef NO_CONSOLE_IO
#define DEBUG_GLOBAL 0
#endif /* ~NO_CONSOLE_IO */
/*------------------------------------------------------------------*
* Adaptive background normalization *
*------------------------------------------------------------------*/
/*!
* pixBackgroundNormSimple()
*
* Input: pixs (8 bpp grayscale or 32 bpp rgb)
* pixim (<optional> 1 bpp 'image' mask; can be null)
* pixg (<optional> 8 bpp grayscale version; can be null)
* Return: pixd (8 bpp or 32 bpp rgb), or null on error
*
* Notes:
* (1) This is a simplified interface to pixBackgroundNorm(),
* where seven parameters are defaulted.
* (2) The input image is either grayscale or rgb.
* (3) See pixBackgroundNorm() for usage and function.
*/
PIX *
pixBackgroundNormSimple(PIX *pixs,
PIX *pixim,
PIX *pixg)
{
return pixBackgroundNorm(pixs, pixim, pixg,
DEFAULT_TILE_WIDTH, DEFAULT_TILE_HEIGHT,
DEFAULT_FG_THRESHOLD, DEFAULT_MIN_COUNT,
DEFAULT_BG_VAL, DEFAULT_X_SMOOTH_SIZE,
DEFAULT_Y_SMOOTH_SIZE);
}
/*!
* pixBackgroundNorm()
*
* Input: pixs (8 bpp grayscale or 32 bpp rgb)
* pixim (<optional> 1 bpp 'image' mask; can be null)
* pixg (<optional> 8 bpp grayscale version; can be null)
* sx, sy (tile size in pixels)
* thresh (threshold for determining foreground)
* mincount (min threshold on counts in a tile)
* bgval (target bg val; typ. > 128)
* smoothx (half-width of block convolution kernel width)
* smoothy (half-width of block convolution kernel height)
* Return: pixd (8 bpp or 32 bpp rgb), or null on error
*
* Notes:
* (1) This is a top-level interface for normalizing the image intensity
* by mapping the image so that the background is near the input
* value 'bgval'.
* (2) The input image is either grayscale or rgb.
* (3) For each component in the input image, the background value
* in each tile is estimated using the values in the tile that
* are not part of the foreground, where the foreground is
* determined by the input 'thresh' argument.
* (4) An optional binary mask can be specified, with the foreground
* pixels typically over image regions. The resulting background
* map values will be determined by surrounding pixels that are
* not under the mask foreground. The origin (0,0) of this mask
* is assumed to be aligned with the origin of the input image.
* This binary mask must not fully cover pixs, because then there
* will be no pixels in the input image available to compute
* the background.
* (5) An optional grayscale version of the input pixs can be supplied.
* The only reason to do this is if the input is RGB and this
* grayscale version can be used elsewhere. If the input is RGB
* and this is not supplied, it is made internally using only
* the green component, and destroyed after use.
* (6) The dimensions of the pixel tile (sx, sy) give the amount by
* by which the map is reduced in size from the input image.
* (7) The threshold is used to binarize the input image, in order to
* locate the foreground components. If this is set too low,
* some actual foreground may be used to determine the maps;
* if set too high, there may not be enough background
* to determine the map values accurately. Typically, it's
* better to err by setting the threshold too high.
* (8) A 'mincount' threshold is a minimum count of pixels in a
* tile for which a background reading is made, in order for that
* pixel in the map to be valid. This number should perhaps be
* at least 1/3 the size of the tile.
* (9) A 'bgval' target background value for the normalized image. This
* should be at least 128. If set too close to 255, some
* clipping will occur in the result.
* (10) Two factors, 'smoothx' and 'smoothy', are input for smoothing
* the map. Each low-pass filter kernel dimension is
* is 2 * (smoothing factor) + 1, so a
* value of 0 means no smoothing. A value of 1 or 2 is recommended.
*/
PIX *
pixBackgroundNorm(PIX *pixs,
PIX *pixim,
PIX *pixg,
l_int32 sx,
l_int32 sy,
l_int32 thresh,
l_int32 mincount,
l_int32 bgval,
l_int32 smoothx,
l_int32 smoothy)
{
l_int32 d, allfg;
PIX *pixm, *pixmi, *pixd;
PIX *pixmr, *pixmg, *pixmb, *pixmri, *pixmgi, *pixmbi;
PROCNAME("pixBackgroundNorm");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
d = pixGetDepth(pixs);
if (d != 8 && d != 32)
return (PIX *)ERROR_PTR("pixs not 8 or 32 bpp", procName, NULL);
if (sx < 4 || sy < 4)
return (PIX *)ERROR_PTR("sx and sy must be >= 4", procName, NULL);
if (mincount > sx * sy) {
L_WARNING("mincount too large for tile size", procName);
mincount = (sx * sy) / 3;
}
/* If pixim exists, verify that it is not all foreground. */
if (pixim) {
pixInvert(pixim, pixim);
pixZero(pixim, &allfg);
pixInvert(pixim, pixim);
if (allfg)
return (PIX *)ERROR_PTR("pixim all foreground", procName, NULL);
}
pixd = NULL;
if (d == 8) {
pixm = NULL;
pixGetBackgroundGrayMap(pixs, pixim, sx, sy, thresh, mincount, &pixm);
if (!pixm) {
L_WARNING("map not made; returning a copy of the source", procName);
return pixCopy(NULL, pixs);
}
pixmi = pixGetInvBackgroundMap(pixm, bgval, smoothx, smoothy);
if (!pixmi)
ERROR_PTR("pixmi not made", procName, NULL);
else
pixd = pixApplyInvBackgroundGrayMap(pixs, pixmi, sx, sy);
pixDestroy(&pixm);
pixDestroy(&pixmi);
}
else {
pixmr = pixmg = pixmb = NULL;
pixGetBackgroundRGBMap(pixs, pixim, pixg, sx, sy, thresh,
mincount, &pixmr, &pixmg, &pixmb);
if (!pixmr || !pixmg || !pixmb) {
pixDestroy(&pixmr);
pixDestroy(&pixmg);
pixDestroy(&pixmb);
L_WARNING("map not made; returning a copy of the source", procName);
return pixCopy(NULL, pixs);
}
pixmri = pixGetInvBackgroundMap(pixmr, bgval, smoothx, smoothy);
pixmgi = pixGetInvBackgroundMap(pixmg, bgval, smoothx, smoothy);
pixmbi = pixGetInvBackgroundMap(pixmb, bgval, smoothx, smoothy);
if (!pixmri || !pixmgi || !pixmbi)
ERROR_PTR("not all pixm*i are made", procName, NULL);
else
pixd = pixApplyInvBackgroundRGBMap(pixs, pixmri, pixmgi, pixmbi,
sx, sy);
pixDestroy(&pixmr);
pixDestroy(&pixmg);
pixDestroy(&pixmb);
pixDestroy(&pixmri);
pixDestroy(&pixmgi);
pixDestroy(&pixmbi);
}
if (!pixd)
ERROR_PTR("pixd not made", procName, NULL);
return pixd;
}
/*!
* pixBackgroundNormMorph()
*
* Input: pixs (8 bpp grayscale or 32 bpp rgb)
* pixim (<optional> 1 bpp 'image' mask; can be null)
* reduction (at which morph closings are done; between 2 and 16)
* size (of square Sel for the closing; use an odd number)
* bgval (target bg val; typ. > 128)
* Return: pixd (8 bpp), or null on error
*
* Notes:
* (1) This is a top-level interface for normalizing the image intensity
* by mapping the image so that the background is near the input
* value 'bgval'.
* (2) The input image is either grayscale or rgb.
* (3) For each component in the input image, the background value
* is estimated using a grayscale closing; hence the 'Morph'
* in the function name.
* (4) An optional binary mask can be specified, with the foreground
* pixels typically over image regions. The resulting background
* map values will be determined by surrounding pixels that are
* not under the mask foreground. The origin (0,0) of this mask
* is assumed to be aligned with the origin of the input image.
* This binary mask must not fully cover pixs, because then there
* will be no pixels in the input image available to compute
* the background.
* (5) The map is computed at reduced size (given by 'reduction')
* from the input pixs and optional pixim. At this scale,
* pixs is closed to remove the background, using a square Sel
* of odd dimension. The product of reduction * size should be
* large enough to remove most of the text foreground.
* (6) No convolutional smoothing needs to be done on the map before
* inverting it.
* (7) A 'bgval' target background value for the normalized image. This
* should be at least 128. If set too close to 255, some
* clipping will occur in the result.
*/
PIX *
pixBackgroundNormMorph(PIX *pixs,
PIX *pixim,
l_int32 reduction,
l_int32 size,
l_int32 bgval)
{
l_int32 d, allfg;
PIX *pixm, *pixmi, *pixd;
PIX *pixmr, *pixmg, *pixmb, *pixmri, *pixmgi, *pixmbi;
PROCNAME("pixBackgroundNormMorph");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
d = pixGetDepth(pixs);
if (d != 8 && d != 32)
return (PIX *)ERROR_PTR("pixs not 8 or 32 bpp", procName, NULL);
if (reduction < 2 || reduction > 16)
return (PIX *)ERROR_PTR("reduction must be between 2 and 16",
procName, NULL);
/* If pixim exists, verify that it is not all foreground. */
if (pixim) {
pixInvert(pixim, pixim);
pixZero(pixim, &allfg);
pixInvert(pixim, pixim);
if (allfg)
return (PIX *)ERROR_PTR("pixim all foreground", procName, NULL);
}
pixd = NULL;
if (d == 8) {
pixGetBackgroundGrayMapMorph(pixs, pixim, reduction, size, &pixm);
if (!pixm)
return (PIX *)ERROR_PTR("pixm not made", procName, NULL);
pixmi = pixGetInvBackgroundMap(pixm, bgval, 0, 0);
if (!pixmi)
ERROR_PTR("pixmi not made", procName, NULL);
else
pixd = pixApplyInvBackgroundGrayMap(pixs, pixmi,
reduction, reduction);
pixDestroy(&pixm);
pixDestroy(&pixmi);
}
else { /* d == 32 */
pixmr = pixmg = pixmb = NULL;
pixGetBackgroundRGBMapMorph(pixs, pixim, reduction, size,
&pixmr, &pixmg, &pixmb);
if (!pixmr || !pixmg || !pixmb) {
pixDestroy(&pixmr);
pixDestroy(&pixmg);
pixDestroy(&pixmb);
return (PIX *)ERROR_PTR("not all pixm*", procName, NULL);
}
pixmri = pixGetInvBackgroundMap(pixmr, bgval, 0, 0);
pixmgi = pixGetInvBackgroundMap(pixmg, bgval, 0, 0);
pixmbi = pixGetInvBackgroundMap(pixmb, bgval, 0, 0);
if (!pixmri || !pixmgi || !pixmbi)
ERROR_PTR("not all pixm*i are made", procName, NULL);
else
pixd = pixApplyInvBackgroundRGBMap(pixs, pixmri, pixmgi, pixmbi,
reduction, reduction);
pixDestroy(&pixmr);
pixDestroy(&pixmg);
pixDestroy(&pixmb);
pixDestroy(&pixmri);
pixDestroy(&pixmgi);
pixDestroy(&pixmbi);
}
if (!pixd)
ERROR_PTR("pixd not made", procName, NULL);
return pixd;
}
/*-------------------------------------------------------------------------*
* Arrays of inverted background values for normalization *
*-------------------------------------------------------------------------*
* Notes for these four functions: *
* (1) They are useful if you need to save the actual mapping array. *
* (2) They could be used in the top-level functions but are *
* not because their use makes those functions less clear. *
* (3) Each component in the input pixs generates a 16 bpp pix array. *
*-------------------------------------------------------------------------*/
/*!
* pixBackgroundNormGrayArray()
*
* Input: pixs (8 bpp grayscale)
* pixim (<optional> 1 bpp 'image' mask; can be null)
* sx, sy (tile size in pixels)
* thresh (threshold for determining foreground)
* mincount (min threshold on counts in a tile)
* bgval (target bg val; typ. > 128)
* smoothx (half-width of block convolution kernel width)
* smoothy (half-width of block convolution kernel height)
* &pixd (<return> 16 bpp array of inverted background value)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) See notes in pixBackgroundNorm().
* (2) This returns a 16 bpp pix that can be used by
* pixApplyInvBackgroundGrayMap() to generate a normalized version
* of the input pixs.
*/
l_int32
pixBackgroundNormGrayArray(PIX *pixs,
PIX *pixim,
l_int32 sx,
l_int32 sy,
l_int32 thresh,
l_int32 mincount,
l_int32 bgval,
l_int32 smoothx,
l_int32 smoothy,
PIX **ppixd)
{
l_int32 allfg;
PIX *pixm;
PROCNAME("pixBackgroundNormGrayArray");
if (!ppixd)
return ERROR_INT("&pixd not defined", procName, 1);
*ppixd = NULL;
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
if (pixGetDepth(pixs) != 8)
return ERROR_INT("pixs not 8 bpp", procName, 1);
if (pixim && pixGetDepth(pixim) != 1)
return ERROR_INT("pixim not 1 bpp", procName, 1);
if (sx < 4 || sy < 4)
return ERROR_INT("sx and sy must be >= 4", procName, 1);
if (mincount > sx * sy) {
L_WARNING("mincount too large for tile size", procName);
mincount = (sx * sy) / 3;
}
/* If pixim exists, verify that it is not all foreground. */
if (pixim) {
pixInvert(pixim, pixim);
pixZero(pixim, &allfg);
pixInvert(pixim, pixim);
if (allfg)
return ERROR_INT("pixim all foreground", procName, 1);
}
pixGetBackgroundGrayMap(pixs, pixim, sx, sy, thresh, mincount, &pixm);
if (!pixm)
return ERROR_INT("pixm not made", procName, 1);
*ppixd = pixGetInvBackgroundMap(pixm, bgval, smoothx, smoothy);
pixDestroy(&pixm);
return 0;
}
/*!
* pixBackgroundNormRGBArrays()
*
* Input: pixs (32 bpp rgb)
* pixim (<optional> 1 bpp 'image' mask; can be null)
* pixg (<optional> 8 bpp grayscale version; can be null)
* sx, sy (tile size in pixels)
* thresh (threshold for determining foreground)
* mincount (min threshold on counts in a tile)
* bgval (target bg val; typ. > 128)
* smoothx (half-width of block convolution kernel width)
* smoothy (half-width of block convolution kernel height)
* &pixr (<return> 16 bpp array of inverted R background value)
* &pixg (<return> 16 bpp array of inverted G background value)
* &pixb (<return> 16 bpp array of inverted B background value)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) See notes in pixBackgroundNorm().
* (2) This returns a set of three 16 bpp pix that can be used by
* pixApplyInvBackgroundGrayMap() to generate a normalized version
* of each component of the input pixs.
*/
l_int32
pixBackgroundNormRGBArrays(PIX *pixs,
PIX *pixim,
PIX *pixg,
l_int32 sx,
l_int32 sy,
l_int32 thresh,
l_int32 mincount,
l_int32 bgval,
l_int32 smoothx,
l_int32 smoothy,
PIX **ppixr,
PIX **ppixg,
PIX **ppixb)
{
l_int32 allfg;
PIX *pixmr, *pixmg, *pixmb;
PROCNAME("pixBackgroundNormRGBArrays");
if (!ppixr || !ppixg || !ppixb)
return ERROR_INT("&pixr, &pixg, &pixb not all defined", procName, 1);
*ppixr = *ppixg = *ppixb = NULL;
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
if (pixGetDepth(pixs) != 32)
return ERROR_INT("pixs not 32 bpp", procName, 1);
if (pixim && pixGetDepth(pixim) != 1)
return ERROR_INT("pixim not 1 bpp", procName, 1);
if (sx < 4 || sy < 4)
return ERROR_INT("sx and sy must be >= 4", procName, 1);
if (mincount > sx * sy) {
L_WARNING("mincount too large for tile size", procName);
mincount = (sx * sy) / 3;
}
/* If pixim exists, verify that it is not all foreground. */
if (pixim) {
pixInvert(pixim, pixim);
pixZero(pixim, &allfg);
pixInvert(pixim, pixim);
if (allfg)
return ERROR_INT("pixim all foreground", procName, 1);
}
pixGetBackgroundRGBMap(pixs, pixim, pixg, sx, sy, thresh, mincount,
&pixmr, &pixmg, &pixmb);
if (!pixmr || !pixmg || !pixmb) {
pixDestroy(&pixmr);
pixDestroy(&pixmg);
pixDestroy(&pixmb);
return ERROR_INT("not all pixm* made", procName, 1);
}
*ppixr = pixGetInvBackgroundMap(pixmr, bgval, smoothx, smoothy);
*ppixg = pixGetInvBackgroundMap(pixmg, bgval, smoothx, smoothy);
*ppixb = pixGetInvBackgroundMap(pixmb, bgval, smoothx, smoothy);
pixDestroy(&pixmr);
pixDestroy(&pixmg);
pixDestroy(&pixmb);
return 0;
}
/*!
* pixBackgroundNormGrayArrayMorph()
*
* Input: pixs (8 bpp grayscale)
* pixim (<optional> 1 bpp 'image' mask; can be null)
* reduction (at which morph closings are done; between 2 and 16)
* size (of square Sel for the closing; use an odd number)
* bgval (target bg val; typ. > 128)
* &pixd (<return> 16 bpp array of inverted background value)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) See notes in pixBackgroundNormMorph().
* (2) This returns a 16 bpp pix that can be used by
* pixApplyInvBackgroundGrayMap() to generate a normalized version
* of the input pixs.
*/
l_int32
pixBackgroundNormGrayArrayMorph(PIX *pixs,
PIX *pixim,
l_int32 reduction,
l_int32 size,
l_int32 bgval,
PIX **ppixd)
{
l_int32 allfg;
PIX *pixm;
PROCNAME("pixBackgroundNormGrayArrayMorph");
if (!ppixd)
return ERROR_INT("&pixd not defined", procName, 1);
*ppixd = NULL;
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
if (pixGetDepth(pixs) != 8)
return ERROR_INT("pixs not 8 bpp", procName, 1);
if (pixim && pixGetDepth(pixim) != 1)
return ERROR_INT("pixim not 1 bpp", procName, 1);
if (reduction < 2 || reduction > 16)
return ERROR_INT("reduction must be between 2 and 16", procName, 1);
/* If pixim exists, verify that it is not all foreground. */
if (pixim) {
pixInvert(pixim, pixim);
pixZero(pixim, &allfg);
pixInvert(pixim, pixim);
if (allfg)
return ERROR_INT("pixim all foreground", procName, 1);
}
pixGetBackgroundGrayMapMorph(pixs, pixim, reduction, size, &pixm);
if (!pixm)
return ERROR_INT("pixm not made", procName, 1);
*ppixd = pixGetInvBackgroundMap(pixm, bgval, 0, 0);
pixDestroy(&pixm);
return 0;
}
/*!
* pixBackgroundNormRGBArraysMorph()
*
* Input: pixs (32 bpp rgb)
* pixim (<optional> 1 bpp 'image' mask; can be null)
* reduction (at which morph closings are done; between 2 and 16)
* size (of square Sel for the closing; use an odd number)
* bgval (target bg val; typ. > 128)
* &pixr (<return> 16 bpp array of inverted R background value)
* &pixg (<return> 16 bpp array of inverted G background value)
* &pixb (<return> 16 bpp array of inverted B background value)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) See notes in pixBackgroundNormMorph().
* (2) This returns a set of three 16 bpp pix that can be used by
* pixApplyInvBackgroundGrayMap() to generate a normalized version
* of each component of the input pixs.
*/
l_int32
pixBackgroundNormRGBArraysMorph(PIX *pixs,
PIX *pixim,
l_int32 reduction,
l_int32 size,
l_int32 bgval,
PIX **ppixr,
PIX **ppixg,
PIX **ppixb)
{
l_int32 allfg;
PIX *pixmr, *pixmg, *pixmb;
PROCNAME("pixBackgroundNormRGBArraysMorph");
if (!ppixr || !ppixg || !ppixb)
return ERROR_INT("&pixr, &pixg, &pixb not all defined", procName, 1);
*ppixr = *ppixg = *ppixb = NULL;
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
if (pixGetDepth(pixs) != 32)
return ERROR_INT("pixs not 32 bpp", procName, 1);
if (pixim && pixGetDepth(pixim) != 1)
return ERROR_INT("pixim not 1 bpp", procName, 1);
if (reduction < 2 || reduction > 16)
return ERROR_INT("reduction must be between 2 and 16", procName, 1);
/* If pixim exists, verify that it is not all foreground. */
if (pixim) {
pixInvert(pixim, pixim);
pixZero(pixim, &allfg);
pixInvert(pixim, pixim);
if (allfg)
return ERROR_INT("pixim all foreground", procName, 1);
}
pixGetBackgroundRGBMapMorph(pixs, pixim, reduction, size,
&pixmr, &pixmg, &pixmb);
if (!pixmr || !pixmg || !pixmb) {
pixDestroy(&pixmr);
pixDestroy(&pixmg);
pixDestroy(&pixmb);
return ERROR_INT("not all pixm* made", procName, 1);
}
*ppixr = pixGetInvBackgroundMap(pixmr, bgval, 0, 0);
*ppixg = pixGetInvBackgroundMap(pixmg, bgval, 0, 0);
*ppixb = pixGetInvBackgroundMap(pixmb, bgval, 0, 0);
pixDestroy(&pixmr);
pixDestroy(&pixmg);
pixDestroy(&pixmb);
return 0;
}
/*------------------------------------------------------------------*
* Measurement of local background *
*------------------------------------------------------------------*/
/*!
* pixGetBackgroundGrayMap()
*
* Input: pixs (8 bpp)
* pixim (<optional> 1 bpp 'image' mask; can be null; it
* should not have all foreground pixels)
* sx, sy (tile size in pixels)
* thresh (threshold for determining foreground)
* mincount (min threshold on counts in a tile)
* &pixd (<return> 8 bpp grayscale map)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) The background is measured in regions that don't have
* images. It is then propagated into the image regions,
* and finally smoothed in each image region.
*/
l_int32
pixGetBackgroundGrayMap(PIX *pixs,
PIX *pixim,
l_int32 sx,
l_int32 sy,
l_int32 thresh,
l_int32 mincount,
PIX **ppixd)
{
l_int32 w, h, wd, hd, wim, him, wpls, wplim, wpld, wplf;
l_int32 xim, yim, delx, nx, ny, i, j, k, m;
l_int32 count, sum, val8;
l_int32 empty, fgpixels;
l_uint32 *datas, *dataim, *datad, *dataf, *lines, *lineim, *lined, *linef;
l_float32 scalex, scaley;
PIX *pixd, *piximi, *pixb, *pixf, *pixims;
PROCNAME("pixGetBackgroundGrayMap");
if (!ppixd)
return ERROR_INT("&pixd not defined", procName, 1);
*ppixd = NULL;
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
if (pixGetDepth(pixs) != 8)
return ERROR_INT("pixs not 8 bpp", procName, 1);
if (pixim && pixGetDepth(pixim) != 1)
return ERROR_INT("pixim not 1 bpp", procName, 1);
if (sx < 4 || sy < 4)
return ERROR_INT("sx and sy must be >= 4", procName, 1);
if (mincount > sx * sy) {
L_WARNING("mincount too large for tile size", procName);
mincount = (sx * sy) / 3;
}
/* Evaluate the 'image' mask, pixim, and make sure
* it is not all fg. */
fgpixels = 0; /* boolean for existence of fg pixels in the image mask. */
if (pixim) {
piximi = pixInvert(NULL, pixim); /* set non-'image' pixels to 1 */
pixZero(piximi, &empty);
pixDestroy(&piximi);
if (empty)
return ERROR_INT("pixim all fg; no background", procName, 1);
pixZero(pixim, &empty);
if (!empty) /* there are fg pixels in pixim */
fgpixels = 1;
}
/* Generate the foreground mask, pixf, which is at
* full resolution. These pixels will be ignored when
* computing the background values. */
pixb = pixThresholdToBinary(pixs, thresh);
pixf = pixMorphSequence(pixb, "d7.1 + d1.7", 0);
pixDestroy(&pixb);
/* ------------- Set up the output map pixd --------------- */
/* Generate pixd, which is reduced by the factors (sx, sy). */
w = pixGetWidth(pixs);
h = pixGetHeight(pixs);
wd = (w + sx - 1) / sx;
hd = (h + sy - 1) / sy;
pixd = pixCreate(wd, hd, 8);
/* Note: we only compute map values in tiles that are complete.
* In general, tiles at right and bottom edges will not be
* complete, and we must fill them in later. */
nx = w / sx;
ny = h / sy;
wpls = pixGetWpl(pixs);
datas = pixGetData(pixs);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
wplf = pixGetWpl(pixf);
dataf = pixGetData(pixf);
for (i = 0; i < ny; i++) {
lines = datas + sy * i * wpls;
linef = dataf + sy * i * wplf;
lined = datad + i * wpld;
for (j = 0; j < nx; j++) {
delx = j * sx;
sum = 0;
count = 0;
for (k = 0; k < sy; k++) {
for (m = 0; m < sx; m++) {
if (GET_DATA_BIT(linef + k * wplf, delx + m) == 0) {
sum += GET_DATA_BYTE(lines + k * wpls, delx + m);
count++;
}
}
}
if (count >= mincount) {
val8 = sum / count;
SET_DATA_BYTE(lined, j, val8);
}
}
}
pixDestroy(&pixf);
/* If there is an optional mask with fg pixels, erase the previous
* calculation for the corresponding map pixels, setting the
* map values to 0. Then, when all the map holes are filled,
* these erased pixels will be set by the surrounding map values.
*
* The calculation here is relatively efficient: for each pixel
* in pixd (which corresponds to a tile of mask pixels in pixim)
* we look only at the pixel in pixim that is at the center
* of the tile. If the mask pixel is ON, we reset the map
* pixel in pixd to 0, so that it can later be filled in. */
pixims = NULL;
if (pixim && fgpixels) {
wim = pixGetWidth(pixim);
him = pixGetHeight(pixim);
dataim = pixGetData(pixim);
wplim = pixGetWpl(pixim);
for (i = 0; i < ny; i++) {
yim = i * sy + sy / 2;
if (yim >= him)
break;
lineim = dataim + yim * wplim;
for (j = 0; j < nx; j++) {
xim = j * sx + sx / 2;
if (xim >= wim)
break;
if (GET_DATA_BIT(lineim, xim))
pixSetPixel(pixd, j, i, 0);
}
}
}
/* Fill all the holes in the map. */
if (pixFillMapHoles(pixd, nx, ny, L_FILL_BLACK)) {
pixDestroy(&pixd);
L_WARNING("can't make the map", procName);
return 1;
}
/* Finally, for each connected region corresponding to the
* 'image' mask, reset all pixels to their average value.
* Each of these components represents an image (or part of one)
* in the input, and this smooths the background values
* in each of these regions. */
if (pixim && fgpixels) {
scalex = 1. / (l_float32)sx;
scaley = 1. / (l_float32)sy;
pixims = pixScaleBySampling(pixim, scalex, scaley);
pixSmoothConnectedRegions(pixd, pixims, 2);
pixDestroy(&pixims);
}
*ppixd = pixd;
return 0;
}
/*!
* pixGetBackgroundRGBMap()
*
* Input: pixs (32 bpp rgb)
* pixim (<optional> 1 bpp 'image' mask; can be null; it
* should not have all foreground pixels)
* pixg (<optional> 8 bpp grayscale version; can be null)
* sx, sy (tile size in pixels)
* thresh (threshold for determining foreground)
* mincount (min threshold on counts in a tile)
* &pixmr, &pixmg, &pixmb (<return> rgb maps)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) If pixg, which is a grayscale version of pixs, is provided,
* use this internally to generate the foreground mask.
* Otherwise, a grayscale version of pixs will be generated
* from the green component only, used, and destroyed.
*/
l_int32
pixGetBackgroundRGBMap(PIX *pixs,
PIX *pixim,
PIX *pixg,
l_int32 sx,
l_int32 sy,
l_int32 thresh,
l_int32 mincount,
PIX **ppixmr,
PIX **ppixmg,
PIX **ppixmb)
{
l_int32 w, h, wm, hm, wim, him, wpls, wplim, wplf;
l_int32 xim, yim, delx, nx, ny, i, j, k, m;
l_int32 count, rsum, gsum, bsum, rval, gval, bval;
l_int32 empty, fgpixels;
l_uint32 pixel;
l_uint32 *datas, *dataim, *dataf, *lines, *lineim, *linef;
l_float32 scalex, scaley;
PIX *piximi, *pixgc, *pixb, *pixf, *pixims;
PIX *pixmr, *pixmg, *pixmb;
PROCNAME("pixGetBackgroundRGBMap");
if (!ppixmr || !ppixmg || !ppixmb)
return ERROR_INT("&pixm* not all defined", procName, 1);
*ppixmr = *ppixmg = *ppixmb = NULL;
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
if (pixGetDepth(pixs) != 32)
return ERROR_INT("pixs not 32 bpp", procName, 1);
if (pixim && pixGetDepth(pixim) != 1)
return ERROR_INT("pixim not 1 bpp", procName, 1);
if (sx < 4 || sy < 4)
return ERROR_INT("sx and sy must be >= 4", procName, 1);
if (mincount > sx * sy) {
L_WARNING("mincount too large for tile size", procName);
mincount = (sx * sy) / 3;
}
/* Evaluate the mask pixim and make sure it is not all foreground */
fgpixels = 0; /* boolean for existence of fg mask pixels */
if (pixim) {
piximi = pixInvert(NULL, pixim); /* set non-'image' pixels to 1 */
pixZero(piximi, &empty);
pixDestroy(&piximi);
if (empty)
return ERROR_INT("pixim all fg; no background", procName, 1);
pixZero(pixim, &empty);
if (!empty) /* there are fg pixels in pixim */
fgpixels = 1;
}
/* Generate the foreground mask. These pixels will be
* ignored when computing the background values. */
if (pixg) /* use the input grayscale version if it is provided */
pixgc = pixClone(pixg);
else
pixgc = pixConvertRGBToGrayFast(pixs);
pixb = pixThresholdToBinary(pixgc, thresh);
pixf = pixMorphSequence(pixb, "d7.1 + d1.7", 0);
pixDestroy(&pixgc);
pixDestroy(&pixb);
/* Generate the output mask images */
w = pixGetWidth(pixs);
h = pixGetHeight(pixs);
wm = (w + sx - 1) / sx;
hm = (h + sy - 1) / sy;
pixmr = pixCreate(wm, hm, 8);
pixmg = pixCreate(wm, hm, 8);
pixmb = pixCreate(wm, hm, 8);
/* ------------- Set up the mapping images --------------- */
/* Note: we only compute map values in tiles that are complete.
* In general, tiles at right and bottom edges will not be
* complete, and we must fill them in later. */
nx = w / sx;
ny = h / sy;
wpls = pixGetWpl(pixs);
datas = pixGetData(pixs);
wplf = pixGetWpl(pixf);
dataf = pixGetData(pixf);
for (i = 0; i < ny; i++) {
lines = datas + sy * i * wpls;
linef = dataf + sy * i * wplf;
for (j = 0; j < nx; j++) {
delx = j * sx;
rsum = gsum = bsum = 0;
count = 0;
for (k = 0; k < sy; k++) {
for (m = 0; m < sx; m++) {
if (GET_DATA_BIT(linef + k * wplf, delx + m) == 0) {
pixel = *(lines + k * wpls + delx + m);
rsum += (pixel >> 24);
gsum += ((pixel >> 16) & 0xff);
bsum += ((pixel >> 8) & 0xff);
count++;
}
}
}
if (count >= mincount) {
rval = rsum / count;
gval = gsum / count;
bval = bsum / count;
pixSetPixel(pixmr, j, i, rval);
pixSetPixel(pixmg, j, i, gval);
pixSetPixel(pixmb, j, i, bval);
}
}
}
pixDestroy(&pixf);
/* If there is an optional mask with fg pixels, erase the previous
* calculation for the corresponding map pixels, setting the
* map values in each of the 3 color maps to 0. Then, when
* all the map holes are filled, these erased pixels will
* be set by the surrounding map values. */
if (pixim) {
wim = pixGetWidth(pixim);
him = pixGetHeight(pixim);
dataim = pixGetData(pixim);
wplim = pixGetWpl(pixim);
for (i = 0; i < ny; i++) {
yim = i * sy + sy / 2;
if (yim >= him)
break;
lineim = dataim + yim * wplim;
for (j = 0; j < nx; j++) {
xim = j * sx + sx / 2;
if (xim >= wim)
break;
if (GET_DATA_BIT(lineim, xim)) {
pixSetPixel(pixmr, j, i, 0);
pixSetPixel(pixmg, j, i, 0);
pixSetPixel(pixmb, j, i, 0);
}
}
}
}
/* ----------------- Now fill in the holes ----------------------- */
if (pixFillMapHoles(pixmr, nx, ny, L_FILL_BLACK) ||
pixFillMapHoles(pixmg, nx, ny, L_FILL_BLACK) ||
pixFillMapHoles(pixmb, nx, ny, L_FILL_BLACK)) {
pixDestroy(&pixmr);
pixDestroy(&pixmg);
pixDestroy(&pixmb);
L_WARNING("can't make the maps", procName);
return 1;
}
/* Finally, for each connected region corresponding to the
* fg mask, reset all pixels to their average value. */
if (pixim && fgpixels) {
scalex = 1. / (l_float32)sx;
scaley = 1. / (l_float32)sy;
pixims = pixScaleBySampling(pixim, scalex, scaley);
pixSmoothConnectedRegions(pixmr, pixims, 2);
pixSmoothConnectedRegions(pixmg, pixims, 2);
pixSmoothConnectedRegions(pixmb, pixims, 2);
pixDestroy(&pixims);
}
*ppixmr = pixmr;
*ppixmg = pixmg;
*ppixmb = pixmb;
return 0;
}
/*!
* pixGetBackgroundGrayMapMorph()
*
* Input: pixs (8 bpp)
* pixim (<optional> 1 bpp 'image' mask; can be null; it
* should not have all foreground pixels)
* reduction (factor at which closing is performed)
* size (of square Sel for the closing; use an odd number)
* &pixm (<return> grayscale map)
* Return: 0 if OK, 1 on error
*/
l_int32
pixGetBackgroundGrayMapMorph(PIX *pixs,
PIX *pixim,
l_int32 reduction,
l_int32 size,
PIX **ppixm)
{
l_int32 nx, ny, empty, fgpixels;
l_float32 scale;
PIX *pixm, *pixt1, *pixt2, *pixt3, *pixims;
PROCNAME("pixGetBackgroundGrayMapMorph");
if (!ppixm)
return ERROR_INT("&pixm not defined", procName, 1);
*ppixm = NULL;
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
if (pixGetDepth(pixs) != 8)
return ERROR_INT("pixs not 8 bpp", procName, 1);
if (pixim && pixGetDepth(pixim) != 1)
return ERROR_INT("pixim not 1 bpp", procName, 1);
/* Evaluate the mask pixim and make sure it is not all foreground. */
fgpixels = 0; /* boolean for existence of fg mask pixels */
if (pixim) {
pixInvert(pixim, pixim); /* set background pixels to 1 */
pixZero(pixim, &empty);
if (empty)
return ERROR_INT("pixim all fg; no background", procName, 1);
pixInvert(pixim, pixim); /* revert to original mask */
pixZero(pixim, &empty);
if (!empty) /* there are fg pixels in pixim */
fgpixels = 1;
}
/* Downscale as requested and do the closing to get the background. */
scale = 1. / (l_float32)reduction;
pixt1 = pixScaleBySampling(pixs, scale, scale);
pixt2 = pixCloseGray(pixt1, size, size);
pixt3 = pixExtendByReplication(pixt2, 1, 1);
/* Downscale the image mask, if any, and remove it from the
* background. These pixels will be filled in (twice). */
pixims = NULL;
if (pixim) {
pixims = pixScale(pixim, scale, scale);
pixm = pixConvertTo8(pixims, FALSE);
pixAnd(pixm, pixm, pixt3);
}
else
pixm = pixClone(pixt3);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixt3);
/* Fill all the holes in the map. */
nx = pixGetWidth(pixs) / reduction;
ny = pixGetHeight(pixs) / reduction;
if (pixFillMapHoles(pixm, nx, ny, L_FILL_BLACK)) {
pixDestroy(&pixm);
L_WARNING("can't make the map", procName);
return 1;
}
/* Finally, for each connected region corresponding to the
* fg mask, reset all pixels to their average value. */
if (pixim && fgpixels) {
pixSmoothConnectedRegions(pixm, pixims, 2);
pixDestroy(&pixims);
}
*ppixm = pixm;
return 0;
}
/*!
* pixGetBackgroundRGBMapMorph()
*
* Input: pixs (32 bpp rgb)
* pixim (<optional> 1 bpp 'image' mask; can be null; it
* should not have all foreground pixels)
* reduction (factor at which closing is performed)
* size (of square Sel for the closing; use an odd number)
* &pixmr (<return> red component map)
* &pixmg (<return> green component map)
* &pixmb (<return> blue component map)
* Return: 0 if OK, 1 on error
*/
l_int32
pixGetBackgroundRGBMapMorph(PIX *pixs,
PIX *pixim,
l_int32 reduction,
l_int32 size,
PIX **ppixmr,
PIX **ppixmg,
PIX **ppixmb)
{
l_int32 nx, ny, empty, fgpixels;
l_float32 scale;
PIX *pixm, *pixmr, *pixmg, *pixmb, *pixt1, *pixt2, *pixt3, *pixims;
PROCNAME("pixGetBackgroundRGBMapMorph");
if (!ppixmr || !ppixmg || !ppixmb)
return ERROR_INT("&pixm* not all defined", procName, 1);
*ppixmr = *ppixmg = *ppixmb = NULL;
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
if (pixGetDepth(pixs) != 32)
return ERROR_INT("pixs not 32 bpp", procName, 1);
if (pixim && pixGetDepth(pixim) != 1)
return ERROR_INT("pixim not 1 bpp", procName, 1);
/* Generate an 8 bpp version of the image mask, if it exists */
scale = 1. / (l_float32)reduction;
pixm = NULL;
if (pixim) {
pixims = pixScale(pixim, scale, scale);
pixm = pixConvertTo8(pixims, FALSE);
}
/* Evaluate the mask pixim and make sure it is not all foreground. */
fgpixels = 0; /* boolean for existence of fg mask pixels */
if (pixim) {
pixInvert(pixim, pixim); /* set background pixels to 1 */
pixZero(pixim, &empty);
if (empty)
return ERROR_INT("pixim all fg; no background", procName, 1);
pixInvert(pixim, pixim); /* revert to original mask */
pixZero(pixim, &empty);
if (!empty) /* there are fg pixels in pixim */
fgpixels = 1;
}
/* Downscale as requested and do the closing to get the background.
* Then remove the image mask pixels from the background. They
* will be filled in (twice) later. Do this for all 3 components. */
pixt1 = pixScaleRGBToGrayFast(pixs, reduction, COLOR_RED);
pixt2 = pixCloseGray(pixt1, size, size);
pixt3 = pixExtendByReplication(pixt2, 1, 1);
if (pixim)
pixmr = pixAnd(NULL, pixm, pixt3);
else
pixmr = pixClone(pixt3);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixt3);
pixt1 = pixScaleRGBToGrayFast(pixs, reduction, COLOR_GREEN);
pixt2 = pixCloseGray(pixt1, size, size);
pixt3 = pixExtendByReplication(pixt2, 1, 1);
if (pixim)
pixmg = pixAnd(NULL, pixm, pixt3);
else
pixmg = pixClone(pixt3);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixt3);
pixt1 = pixScaleRGBToGrayFast(pixs, reduction, COLOR_BLUE);
pixt2 = pixCloseGray(pixt1, size, size);
pixt3 = pixExtendByReplication(pixt2, 1, 1);
if (pixim)
pixmb = pixAnd(NULL, pixm, pixt3);
else
pixmb = pixClone(pixt3);
pixDestroy(&pixm);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixt3);
/* Fill all the holes in the three maps. */
nx = pixGetWidth(pixs) / reduction;
ny = pixGetHeight(pixs) / reduction;
if (pixFillMapHoles(pixmr, nx, ny, L_FILL_BLACK) ||
pixFillMapHoles(pixmg, nx, ny, L_FILL_BLACK) ||
pixFillMapHoles(pixmb, nx, ny, L_FILL_BLACK)) {
pixDestroy(&pixmr);
pixDestroy(&pixmg);
pixDestroy(&pixmb);
L_WARNING("can't make the maps", procName);
return 1;
}
/* Finally, for each connected region corresponding to the
* fg mask in each component, reset all pixels to their
* average value. */
if (pixim && fgpixels) {
pixSmoothConnectedRegions(pixmr, pixims, 2);
pixSmoothConnectedRegions(pixmg, pixims, 2);
pixSmoothConnectedRegions(pixmb, pixims, 2);
pixDestroy(&pixims);
}
*ppixmr = pixmr;
*ppixmg = pixmg;
*ppixmb = pixmb;
return 0;
}
/*!
* pixFillMapHoles()
*
* Input: pix (8 bpp; a map, with one pixel for each tile in
* a larger image)
* nx (number of horizontal pixel tiles that are entirely
* covered with pixels in the original source image)
* ny (ditto for the number of vertical pixel tiles)
* filltype (L_FILL_WHITE or L_FILL_BLACK)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) This is an in-place operation on pix (the map). pix is
* typically a low-resolution version of some other image
* from which it was derived, where each pixel in pix
* corresponds to a rectangular tile (say, m x n) of pixels
* in the larger image. All we need to know about the larger
* image is whether or not the rightmost column and bottommost
* row of pixels in pix correspond to tiles that are
* only partially covered by pixels in the larger image.
* (2) Typically, some number of pixels in the input map are
* not known, and their values must be determined by near
* pixels that are known. These unknown pixels are the 'holes'.
* They can take on only two values, 0 and 255, and the
* instruction about which to fill is given by the filltype flag.
* (3) The "holes" can come from two sources. The first is when there
* are not enough foreground or background pixels in a tile;
* the second is when a tile is at least partially covered
* by an image mask. If we're filling holes in a fg mask,
* the holes are initialized to black (0) and use L_FILL_BLACK.
* For filling holes in a bg mask, initialize the holes to
* white (255) and use L_FILL_WHITE.
* (4) If w is the map width, nx = w or nx = w - 1; ditto for h and ny.
*/
l_int32
pixFillMapHoles(PIX *pix,
l_int32 nx,
l_int32 ny,
l_int32 filltype)
{
l_int32 w, h, d, y, nmiss, goodcol, i, j, found, ival, valtest;
l_uint32 val, lastval;
NUMA *na; /* indicates if there is any data in the column */
PIX *pixt;
PROCNAME("pixFillMapHoles");
if (!pix)
return ERROR_INT("pix not defined", procName, 1);
pixGetDimensions(pix, &w, &h, &d);
if (d != 8)
return ERROR_INT("pix not 8 bpp", procName, 1);
/* ------------- Fill holes in the mapping image columns ----------- */
na = numaCreate(0); /* holds flag for which columns have data */
nmiss = 0;
valtest = (filltype == L_FILL_WHITE) ? 255 : 0;
for (j = 0; j < nx; j++) { /* do it by columns */
found = FALSE;
for (i = 0; i < ny; i++) {
pixGetPixel(pix, j, i, &val);
if (val != valtest) {
y = i;
found = TRUE;
break;
}
}
if (found == FALSE) {
numaAddNumber(na, 0); /* no data in the column */
nmiss++;
}
else {
numaAddNumber(na, 1); /* data in the column */
for (i = y - 1; i >= 0; i--) /* replicate upwards to top */
pixSetPixel(pix, j, i, val);
pixGetPixel(pix, j, 0, &lastval);
for (i = 1; i < h; i++) { /* set going down to bottom */
pixGetPixel(pix, j, i, &val);
if (val == valtest)
pixSetPixel(pix, j, i, lastval);
else
lastval = val;
}
}
}
numaAddNumber(na, 0); /* last column */
if (nmiss == nx) { /* no data in any column! */
numaDestroy(&na);
L_WARNING("no bg found; no data in any column", procName);
return 1;
}
/* ---------- Fill in missing columns by replication ----------- */
if (nmiss > 0) { /* replicate columns */
pixt = pixCopy(NULL, pix);
/* Find the first good column */
goodcol = 0;
for (j = 0; j < w; j++) {
numaGetIValue(na, j, &ival);
if (ival == 1) {
goodcol = j;
break;
}
}
if (goodcol > 0) { /* copy cols backward */
for (j = goodcol - 1; j >= 0; j--) {
pixRasterop(pix, j, 0, 1, h, PIX_SRC, pixt, j + 1, 0);
pixRasterop(pixt, j, 0, 1, h, PIX_SRC, pix, j, 0);
}
}
for (j = goodcol + 1; j < w; j++) { /* copy cols forward */
numaGetIValue(na, j, &ival);
if (ival == 0) {
/* Copy the column to the left of j */
pixRasterop(pix, j, 0, 1, h, PIX_SRC, pixt, j - 1, 0);
pixRasterop(pixt, j, 0, 1, h, PIX_SRC, pix, j, 0);
}
}
pixDestroy(&pixt);
}
if (w > nx) { /* replicate the last column */
for (i = 0; i < h; i++) {
pixGetPixel(pix, w - 2, i, &val);
pixSetPixel(pix, w - 1, i, val);
}
}
numaDestroy(&na);
return 0;
}
/*!
* pixExtendByReplication()
*
* Input: pixs (8 bpp)
* addw (number of extra pixels horizontally to add)
* addh (number of extra pixels vertically to add)
* Return: pixd (extended with replicated pixel values), or null on error
*
* Notes:
* (1) The pixel values are extended to the left and down, as required.
*/
PIX *
pixExtendByReplication(PIX *pixs,
l_int32 addw,
l_int32 addh)
{
l_int32 w, h, i, j;
l_uint32 val;
PIX *pixd;
PROCNAME("pixExtendByReplication");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
if (addw == 0 && addh == 0)
return pixCopy(NULL, pixs);
w = pixGetWidth(pixs);
h = pixGetHeight(pixs);
if ((pixd = pixCreate(w + addw, h + addh, 8)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixRasterop(pixd, 0, 0, w, h, PIX_SRC, pixs, 0, 0);
if (addw > 0) {
for (i = 0; i < h; i++) {
pixGetPixel(pixd, w - 1, i, &val);
for (j = 0; j < addw; j++)
pixSetPixel(pixd, w + j, i, val);
}
}
if (addh > 0) {
for (j = 0; j < w + addw; j++) {
pixGetPixel(pixd, j, h - 1, &val);
for (i = 0; i < addh; i++)
pixSetPixel(pixd, j, h + i, val);
}
}
return pixd;
}
/*!
* pixSmoothConnectedRegions()
*
* Input: pixs (8 bpp)
* pixm (<optional> 1 bpp; if null, this is a no-op)
* factor (subsampling factor for getting average; >= 1)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) The pixels in pixs corresponding to those in each
* 8-connected region in the mask are set to the average value.
* (2) This is required for adaptive mapping to avoid the
* generation of stripes in the background map, due to
* variations in the pixel values near the edges of mask regions.
* (3) This function is optimized for background smoothing, where
* there are a relatively small number of components. It will
* be inefficient if used where there are many small components.
*/
l_int32
pixSmoothConnectedRegions(PIX *pixs,
PIX *pixm,
l_int32 factor)
{
l_int32 empty, i, n, x, y;
l_float32 aveval;
BOXA *boxa;
PIX *pixmc;
PIXA *pixa;
PROCNAME("pixSmoothConnectedRegions");
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
if (pixGetDepth(pixs) != 8)
return ERROR_INT("pixs not 8 bpp", procName, 1);
if (!pixm) {
L_INFO("pixm not defined", procName);
return 0;
}
if (pixGetDepth(pixm) != 1)
return ERROR_INT("pixm not 1 bpp", procName, 1);
pixZero(pixm, &empty);
if (empty) {
L_INFO("pixm has no fg pixels; nothing to do", procName);
return 0;
}
boxa = pixConnComp(pixm, &pixa, 8);
n = boxaGetCount(boxa);
for (i = 0; i < n; i++) {
if ((pixmc = pixaGetPix(pixa, i, L_CLONE)) == NULL) {
L_WARNING("missing pixmc!", procName);
continue;
}
boxaGetBoxGeometry(boxa, i, &x, &y, NULL, NULL);
pixGetAverageMasked(pixs, pixmc, x, y, factor, L_MEAN_ABSVAL, &aveval);
pixPaintThroughMask(pixs, pixmc, x, y, (l_int32)aveval);
pixDestroy(&pixmc);
}
boxaDestroy(&boxa);
pixaDestroy(&pixa);
return 0;
}
/*------------------------------------------------------------------*
* Measurement of local foreground *
*------------------------------------------------------------------*/
#if 0 /* Not working properly: do not use */
/*!
* pixGetForegroundGrayMap()
*
* Input: pixs (8 bpp)
* pixim (<optional> 1 bpp 'image' mask; can be null)
* sx, sy (src tile size, in pixels)
* thresh (threshold for determining foreground)
* &pixd (<return> 8 bpp grayscale map)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) Each (sx, sy) tile of pixs gets mapped to one pixel in pixd.
* (2) pixd is the estimate of the fg (darkest) value within each tile.
* (3) All pixels in pixd that are in 'image' regions, as specified
* by pixim, are given the background value 0.
* (4) For pixels in pixd that can't directly be given a fg value,
* the value is inferred by propagating from neighboring pixels.
* (5) In practice, pixd can be used to normalize the fg, and
* it can be done after background normalization.
* (6) The overall procedure is:
* - reduce 2x by sampling
* - paint all 'image' pixels white, so that they don't
* participate in the Min reduction
* - do a further (sx, sy) Min reduction -- think of
* it as a large opening followed by subsampling by the
* reduction factors
* - threshold the result to identify fg, and set the
* bg pixels to 255 (these are 'holes')
* - fill holes by propagation from fg values
* - replicatively expand by 2x, arriving at the final
* resolution of pixd
* - smooth with a 17x17 kernel
* - paint the 'image' regions black
*/
l_int32
pixGetForegroundGrayMap(PIX *pixs,
PIX *pixim,
l_int32 sx,
l_int32 sy,
l_int32 thresh,
PIX **ppixd)
{
l_int32 w, h, d, wd, hd;
l_int32 empty, fgpixels;
PIX *pixd, *piximi, *pixim2, *pixims, *pixs2, *pixb, *pixt1, *pixt2, *pixt3;
PROCNAME("pixGetForegroundGrayMap");
if (!ppixd)
return ERROR_INT("&pixd not defined", procName, 1);
*ppixd = NULL;
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 8)
return ERROR_INT("pixs not 8 bpp", procName, 1);
if (pixim && pixGetDepth(pixim) != 1)
return ERROR_INT("pixim not 1 bpp", procName, 1);
if (sx < 2 || sy < 2)
return ERROR_INT("sx and sy must be >= 2", procName, 1);
/* Generate pixd, which is reduced by the factors (sx, sy). */
wd = (w + sx - 1) / sx;
hd = (h + sy - 1) / sy;
pixd = pixCreate(wd, hd, 8);
*ppixd = pixd;
/* Evaluate the 'image' mask, pixim. If it is all fg,
* the output pixd has all pixels with value 0. */
fgpixels = 0; /* boolean for existence of fg pixels in the image mask. */
if (pixim) {
piximi = pixInvert(NULL, pixim); /* set non-image pixels to 1 */
pixZero(piximi, &empty);
pixDestroy(&piximi);
if (empty) /* all 'image'; return with all pixels set to 0 */
return 0;
pixZero(pixim, &empty);
if (!empty) /* there are fg pixels in pixim */
fgpixels = 1;
}
/* 2x subsampling; paint white through 'image' mask. */
pixs2 = pixScaleBySampling(pixs, 0.5, 0.5);
if (pixim && fgpixels) {
pixim2 = pixReduceBinary2(pixim, NULL);
pixPaintThroughMask(pixs2, pixim2, 0, 0, 255);
pixDestroy(&pixim2);
}
/* Min (erosion) downscaling; total reduction (4 sx, 4 sy). */
pixt1 = pixScaleGrayMinMax(pixs2, sx, sy, L_CHOOSE_MIN);
/* pixDisplay(pixt1, 300, 200); */
/* Threshold to identify fg; paint bg pixels to white. */
pixb = pixThresholdToBinary(pixt1, thresh); /* fg pixels */
pixInvert(pixb, pixb);
pixPaintThroughMask(pixt1, pixb, 0, 0, 255);
pixDestroy(&pixb);
/* Replicative expansion by 2x to (sx, sy). */
pixt2 = pixExpandReplicate(pixt1, 2);
/* pixDisplay(pixt2, 500, 200); */
/* Fill holes in the fg by propagation */
pixFillMapHoles(pixt2, w / sx, h / sy, L_FILL_WHITE);
/* pixDisplay(pixt2, 700, 200); */
/* Smooth with 17x17 kernel. */
pixt3 = pixBlockconv(pixt2, 8, 8);
pixRasterop(pixd, 0, 0, wd, hd, PIX_SRC, pixt3, 0, 0);
/* Paint the image parts black. */
pixims = pixScaleBySampling(pixim, 1. / sx, 1. / sy);
pixPaintThroughMask(pixd, pixims, 0, 0, 0);
pixDestroy(&pixs2);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixt3);
return 0;
}
#endif /* Not working properly: do not use */
/*------------------------------------------------------------------*
* Generate inverted background map *
*------------------------------------------------------------------*/
/*!
* pixGetInvBackgroundMap()
*
* Input: pixs (8 bpp)
* bgval (target bg val; typ. > 128)
* smoothx (half-width of block convolution kernel width)
* smoothy (half-width of block convolution kernel height)
* Return: pixd (16 bpp), or null on error
*
* Note:
* - bgval should typically be > 120 and < 240
* - pixd is a normalization image; the original image is
* multiplied by pixd and the result is divided by 256.
*/
PIX *
pixGetInvBackgroundMap(PIX *pixs,
l_int32 bgval,
l_int32 smoothx,
l_int32 smoothy)
{
l_int32 w, h, wplsm, wpld, i, j;
l_int32 val, val16;
l_uint32 *datasm, *datad, *linesm, *lined;
PIX *pixsm, *pixd;
PROCNAME("pixGetInvBackgroundMap");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
w = pixGetWidth(pixs);
h = pixGetHeight(pixs);
if (w < 5 || h < 5)
return (PIX *)ERROR_PTR("w and h must be >= 5", procName, NULL);
/* smooth the map image */
pixsm = pixBlockconv(pixs, smoothx, smoothy);
datasm = pixGetData(pixsm);
wplsm = pixGetWpl(pixsm);
/* invert the map image, scaling up to preserve dynamic range */
pixd = pixCreate(w, h, 16);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
for (i = 0; i < h; i++) {
linesm = datasm + i * wplsm;
lined = datad + i * wpld;
for (j = 0; j < w; j++) {
val = GET_DATA_BYTE(linesm, j);
if (val > 0)
val16 = (256 * bgval) / val;
else { /* shouldn't happen */
L_WARNING("smoothed bg has 0 pixel!", procName);
val16 = bgval / 2;
}
SET_DATA_TWO_BYTES(lined, j, val16);
}
}
pixDestroy(&pixsm);
return pixd;
}
/*------------------------------------------------------------------*
* Apply background map to image *
*------------------------------------------------------------------*/
/*!
* pixApplyInvBackgroundGrayMap()
*
* Input: pixs (8 bpp)
* pixm (16 bpp, inverse background map)
* sx (tile width in pixels)
* sy (tile height in pixels)
* Return: pixd (8 bpp), or null on error
*/
PIX *
pixApplyInvBackgroundGrayMap(PIX *pixs,
PIX *pixm,
l_int32 sx,
l_int32 sy)
{
l_int32 w, h, wm, hm, wpls, wpld, i, j, k, m, xoff, yoff;
l_int32 vals, vald;
l_uint32 val16;
l_uint32 *datas, *datad, *lines, *lined, *flines, *flined;
PIX *pixd;
PROCNAME("pixApplyInvBackgroundGrayMap");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
if (!pixm)
return (PIX *)ERROR_PTR("pixm not defined", procName, NULL);
if (pixGetDepth(pixm) != 16)
return (PIX *)ERROR_PTR("pixm not 16 bpp", procName, NULL);
if (sx == 0 || sy == 0)
return (PIX *)ERROR_PTR("invalid sx and/or sy", procName, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
w = pixGetWidth(pixs);
h = pixGetHeight(pixs);
wm = pixGetWidth(pixm);
hm = pixGetHeight(pixm);
pixd = pixCreateTemplate(pixs);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
for (i = 0; i < hm; i++) {
lines = datas + sy * i * wpls;
lined = datad + sy * i * wpld;
yoff = sy * i;
for (j = 0; j < wm; j++) {
pixGetPixel(pixm, j, i, &val16);
xoff = sx * j;
for (k = 0; k < sy && yoff + k < h; k++) {
flines = lines + k * wpls;
flined = lined + k * wpld;
for (m = 0; m < sx && xoff + m < w; m++) {
vals = GET_DATA_BYTE(flines, xoff + m);
vald = (vals * val16) / 256;
vald = L_MIN(vald, 255);
SET_DATA_BYTE(flined, xoff + m, vald);
}
}
}
}
return pixd;
}
/*!
* pixApplyInvBackgroundRGBMap()
*
* Input: pixs (32 bpp rbg)
* pixmr (16 bpp, red inverse background map)
* pixmg (16 bpp, green inverse background map)
* pixmb (16 bpp, blue inverse background map)
* sx (tile width in pixels)
* sy (tile height in pixels)
* Return: pixd (32 bpp rbg), or null on error
*/
PIX *
pixApplyInvBackgroundRGBMap(PIX *pixs,
PIX *pixmr,
PIX *pixmg,
PIX *pixmb,
l_int32 sx,
l_int32 sy)
{
l_int32 w, h, wm, hm, wpls, wpld, i, j, k, m, xoff, yoff;
l_int32 rvald, gvald, bvald;
l_uint32 vals;
l_uint32 rval16, gval16, bval16;
l_uint32 *datas, *datad, *lines, *lined, *flines, *flined;
PIX *pixd;
PROCNAME("pixApplyInvBackgroundRGBMap");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("pixs not 32 bpp", procName, NULL);
if (!pixmr || !pixmg || !pixmb)
return (PIX *)ERROR_PTR("pix maps not all defined", procName, NULL);
if (pixGetDepth(pixmr) != 16 || pixGetDepth(pixmg) != 16 ||
pixGetDepth(pixmb) != 16)
return (PIX *)ERROR_PTR("pix maps not all 16 bpp", procName, NULL);
if (sx == 0 || sy == 0)
return (PIX *)ERROR_PTR("invalid sx and/or sy", procName, NULL);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
w = pixGetWidth(pixs);
h = pixGetHeight(pixs);
wm = pixGetWidth(pixmr);
hm = pixGetHeight(pixmr);
pixd = pixCreateTemplate(pixs);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
for (i = 0; i < hm; i++) {
lines = datas + sy * i * wpls;
lined = datad + sy * i * wpld;
yoff = sy * i;
for (j = 0; j < wm; j++) {
pixGetPixel(pixmr, j, i, &rval16);
pixGetPixel(pixmg, j, i, &gval16);
pixGetPixel(pixmb, j, i, &bval16);
xoff = sx * j;
for (k = 0; k < sy && yoff + k < h; k++) {
flines = lines + k * wpls;
flined = lined + k * wpld;
for (m = 0; m < sx && xoff + m < w; m++) {
vals = *(flines + xoff + m);
rvald = ((vals >> 24) * rval16) / 256;
rvald = L_MIN(rvald, 255);
gvald = (((vals >> 16) & 0xff) * gval16) / 256;
gvald = L_MIN(gvald, 255);
bvald = (((vals >> 8) & 0xff) * bval16) / 256;
bvald = L_MIN(bvald, 255);
composeRGBPixel(rvald, gvald, bvald, flined + xoff + m);
}
}
}
}
return pixd;
}
/*------------------------------------------------------------------*
* Apply variable map *
*------------------------------------------------------------------*/
/*!
* pixApplyVariableGrayMap()
*
* Input: pixs (8 bpp)
* pixg (8 bpp, variable map)
* target (typ. 128 for threshold)
* Return: pixd (8 bpp), or null on error
*
* Notes:
* (1) Suppose you have an image that you want to transform based
* on some photometric measurement at each point, such as the
* threshold value for binarization. Representing the photometric
* measurement as an image pixg, you can threshold in input image
* using pixVarThresholdToBinary(). Alternatively, you can map
* the input image pointwise so that the threshold over the
* entire image becomes a constant, such as 128. For example,
* if a pixel in pixg is 150 and the target is 128, the
* corresponding pixel in pixs is mapped linearly to a value
* (128/150) of the input value. If the resulting mapped image
* pixd were then thresholded at 128, you would obtain the
* same result as a direct binarization using pixg with
* pixVarThresholdToBinary().
* (2) The sizes of pixs and pixg must be equal.
*/
PIX *
pixApplyVariableGrayMap(PIX *pixs,
PIX *pixg,
l_int32 target)
{
l_int32 i, j, w, h, d, wpls, wplg, wpld, vals, valg, vald;
l_uint8 *lut;
l_uint32 *datas, *datag, *datad, *lines, *lineg, *lined;
l_float32 fval;
PIX *pixd;
PROCNAME("pixApplyVariableGrayMap");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (!pixg)
return (PIX *)ERROR_PTR("pixg not defined", procName, NULL);
if (!pixSizesEqual(pixs, pixg))
return (PIX *)ERROR_PTR("pix sizes not equal", procName, NULL);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 8)
return (PIX *)ERROR_PTR("depth not 8 bpp", procName, NULL);
/* Generate a LUT for the mapping if the image is large enough
* to warrant the overhead. The LUT is of size 2^16. For the
* index to the table, get the MSB from pixs and the LSB from pixg.
* Note: this LUT is bigger than the typical 32K L1 cache, so
* we expect cache misses. L2 latencies are about 5ns. But
* division is slooooow. For large images, this function is about
* 4x faster when using the LUT. C'est la vie. */
lut = NULL;
if (w * h > 100000) { /* more pixels than 2^16 */
if ((lut = (l_uint8 *)CALLOC(0x10000, sizeof(l_uint8))) == NULL)
return (PIX *)ERROR_PTR("lut not made", procName, NULL);
for (i = 0; i < 256; i++) {
for (j = 0; j < 256; j++) {
fval = (l_float32)(i * target) / (j + 0.5);
lut[(i << 8) + j] = L_MIN(255, (l_int32)(fval + 0.5));
}
}
}
pixd = pixCreateNoInit(w, h, 8);
datad = pixGetData(pixd);
wpld = pixGetWpl(pixd);
datas = pixGetData(pixs);
wpls = pixGetWpl(pixs);
datag = pixGetData(pixg);
wplg = pixGetWpl(pixg);
for (i = 0; i < h; i++) {
lines = datas + i * wpls;
lineg = datag + i * wplg;
lined = datad + i * wpld;
if (lut) {
for (j = 0; j < w; j++) {
vals = GET_DATA_BYTE(lines, j);
valg = GET_DATA_BYTE(lineg, j);
vald = lut[(vals << 8) + valg];
SET_DATA_BYTE(lined, j, vald);
}
}
else {
for (j = 0; j < w; j++) {
vals = GET_DATA_BYTE(lines, j);
valg = GET_DATA_BYTE(lineg, j);
fval = (l_float32)(vals * target) / (valg + 0.5);
vald = L_MIN(255, (l_int32)(fval + 0.5));
SET_DATA_BYTE(lined, j, vald);
}
}
}
if (lut) FREE(lut);
return pixd;
}
/*------------------------------------------------------------------*
* Non-adaptive (global) mapping *
*------------------------------------------------------------------*/
/*!
* pixGlobalNormRGB()
*
* Input: pixd (<optional> null, existing or equal to pixs)
* pixs (32 bpp rgb, or colormapped)
* rval, gval, bval (pixel values in pixs that are
* linearly mapped to mapval)
* mapval (use 255 for mapping to white)
* Return: pixd (32 bpp rgb or colormapped), or null on error
*
* Notes:
* (1) The value of pixd determines if the results are written to a
* new pix (use NULL), in-place to pixs (use pixs), or to some
* other existing pix.
* (2) This does a global normalization of an image where the
* r,g,b color components are not balanced. Thus, white in pixs is
* represented by a set of r,g,b values that are not all 255.
* (3) The input values (rval, gval, bval) should be chosen to
* represent the gray color (mapval, mapval, mapval) in src.
* Thus, this function will map (rval, gval, bval) to that gray color.
* (4) Typically, mapval = 255, so that (rval, gval, bval)
* corresponds to the white point of src. In that case, these
* parameters should be chosen so that few pixels have higher values.
* (5) In all cases, we do a linear TRC separately on each of the
* components, saturating at 255.
* (6) If the input pix is 8 bpp without a colormap, you can get
* this functionality with mapval = 255 by calling:
* pixGammaTRC(pixd, pixs, 1.0, 0, bgval);
* where bgval is the value you want to be mapped to 255.
* Or more generally, if you want bgval to be mapped to mapval:
* pixGammaTRC(pixd, pixs, 1.0, 0, 255 * bgval / mapval);
*/
PIX *
pixGlobalNormRGB(PIX *pixd,
PIX *pixs,
l_int32 rval,
l_int32 gval,
l_int32 bval,
l_int32 mapval)
{
l_int32 w, h, d, i, j, ncolors, rv, gv, bv, wpl;
l_int32 *rarray, *garray, *barray;
l_uint32 *data, *line;
NUMA *nar, *nag, *nab;
PIXCMAP *cmap;
PROCNAME("pixGlobalNormRGB");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
cmap = pixGetColormap(pixs);
pixGetDimensions(pixs, &w, &h, &d);
if (!cmap && d != 32)
return (PIX *)ERROR_PTR("pixs not cmapped or 32 bpp", procName, NULL);
if (mapval <= 0) {
L_WARNING("mapval must be > 0; setting to 255", procName);
mapval = 255;
}
/* Prepare pixd to be a copy of pixs */
if ((pixd = pixCopy(pixd, pixs)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
/* Generate the TRC maps for each component. Make sure the
* upper range for each color is greater than zero. */
nar = numaGammaTRC(1.0, 0, L_MAX(1, 255 * rval / mapval));
nag = numaGammaTRC(1.0, 0, L_MAX(1, 255 * gval / mapval));
nab = numaGammaTRC(1.0, 0, L_MAX(1, 255 * bval / mapval));
if (!nar || !nag || !nab)
return (PIX *)ERROR_PTR("trc maps not all made", procName, pixd);
/* Extract copies of the internal arrays */
rarray = numaGetIArray(nar);
garray = numaGetIArray(nag);
barray = numaGetIArray(nab);
if (!rarray || !garray || !barray)
return (PIX *)ERROR_PTR("*arrays not all made", procName, pixd);
if (cmap) {
ncolors = pixcmapGetCount(cmap);
for (i = 0; i < ncolors; i++) {
pixcmapGetColor(cmap, i, &rv, &gv, &bv);
pixcmapResetColor(cmap, i, rarray[rv], garray[gv], barray[bv]);
}
}
else {
data = pixGetData(pixd);
wpl = pixGetWpl(pixd);
for (i = 0; i < h; i++) {
line = data + i * wpl;
for (j = 0; j < w; j++) {
extractRGBValues(line[j], &rv, &gv, &bv);
composeRGBPixel(rarray[rv], garray[gv], barray[bv], line + j);
}
}
}
numaDestroy(&nar);
numaDestroy(&nag);
numaDestroy(&nab);
FREE(rarray);
FREE(garray);
FREE(barray);
return pixd;
}
/*!
* pixGlobalNormNoSatRGB()
*
* Input: pixd (<optional> null, existing or equal to pixs)
* pixs (32 bpp rgb)
* rval, gval, bval (pixel values in pixs that are
* linearly mapped to mapval; but see below)
* factor (subsampling factor; integer >= 1)
* rank (between 0.0 and 1.0; typ. use a value near 1.0)
* Return: pixd (32 bpp rgb), or null on error
*
* Notes:
* (1) This is a version of pixGlobalNormRGB(), where the output
* intensity is scaled back so that a controlled fraction of
* pixel components is allowed to saturate. See comments in
* pixGlobalNormRGB().
* (2) The value of pixd determines if the results are written to a
* new pix (use NULL), in-place to pixs (use pixs), or to some
* other existing pix.
* (3) This does a global normalization of an image where the
* r,g,b color components are not balanced. Thus, white in pixs is
* represented by a set of r,g,b values that are not all 255.
* (4) The input values (rval, gval, bval) can be chosen to be the
* color that, after normalization, becomes white background.
* For images that are mostly background, the closer these values
* are to the median component values, the closer the resulting
* background will be to gray, becoming white at the brightest places.
* (5) The mapval used in pixGlobalNormRGB() is computed here to
* avoid saturation of any component in the image (save for a
* fraction of the pixels given by the input rank value).
*/
PIX *
pixGlobalNormNoSatRGB(PIX *pixd,
PIX *pixs,
l_int32 rval,
l_int32 gval,
l_int32 bval,
l_int32 factor,
l_float32 rank)
{
l_int32 mapval;
l_float32 rankrval, rankgval, rankbval;
l_float32 rfract, gfract, bfract, maxfract;
PROCNAME("pixGlobalNormNoSatRGB");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("pixs not 32 bpp", procName, NULL);
if (factor < 1)
return (PIX *)ERROR_PTR("sampling factor < 1", procName, NULL);
if (rank < 0.0 || rank > 1.0)
return (PIX *)ERROR_PTR("rank not in [0.0 ... 1.0]", procName, NULL);
if (rval <= 0 || gval <= 0 || bval <= 0)
return (PIX *)ERROR_PTR("invalid estim. color values", procName, NULL);
/* The max value for each component may be larger than the
* input estimated background value. In that case, mapping
* for those pixels would saturate. To prevent saturation,
* we compute the fraction for each component by which we
* would oversaturate. Then take the max of these, and
* reduce, uniformly over all components, the output intensity
* by this value. Then no component will saturate.
* In practice, if rank < 1.0, a fraction of pixels
* may have a component saturate. By keeping rank close to 1.0,
* that fraction can be made arbitrarily small. */
pixGetRankValueMaskedRGB(pixs, NULL, 0, 0, factor, rank, &rankrval,
&rankgval, &rankbval);
rfract = rankrval / (l_float32)rval;
gfract = rankgval / (l_float32)gval;
bfract = rankbval / (l_float32)bval;
maxfract = L_MAX(rfract, gfract);
maxfract = L_MAX(maxfract, bfract);
#if DEBUG_GLOBAL
fprintf(stderr, "rankrval = %7.2f, rankgval = %7.2f, rankbval = %7.2f\n",
rankrval, rankgval, rankbval);
fprintf(stderr, "rfract = %7.4f, gfract = %7.4f, bfract = %7.4f\n",
rfract, gfract, bfract);
#endif /* DEBUG_GLOBAL */
mapval = (l_int32)(255. / maxfract);
pixd = pixGlobalNormRGB(pixd, pixs, rval, gval, bval, mapval);
return pixd;
}
/*------------------------------------------------------------------*
* Adaptive threshold spread normalization *
*------------------------------------------------------------------*/
/*!
* pixThresholdSpreadNorm()
*
* Input: pixs (8 bpp)
* filtertype (L_SOBEL_EDGE or L_TWO_SIDED_EDGE);
* edgethresh (threshold on magnitude of edge filter; typ 10-20)
* smoothx, smoothy (half-width of convolution kernel applied to
* spread threshold: use 0 for no smoothing)
* gamma (gamma correction; typ. about 0.7)
* minval (input value that gives 0 for output; typ. -25)
* maxval (input value that gives 255 for output; typ. 255)
* targetthresh (target threshold for normalization)
* &pixth (<optional return> computed local threshold value)
* &pixb (<optional return> thresholded normalized image)
* &pixd (<optional return> normalized image)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) The basis of this approach is the use of seed spreading
* on a (possibly) sparse set of estimates for the local threshold.
* The resulting dense estimates are smoothed by convolution
* and used to either threshold the input image or normalize it
* with a local transformation that linearly maps the pixels so
* that the local threshold estimate becomes constant over the
* resulting image. This approach is one of several that
* have been suggested (and implemented) by Ray Smith.
* (2) You can use either the Sobel or TwoSided edge filters.
* The results appear to be similar, using typical values
* of edgethresh in the rang 10-20.
* (3) To skip the trc enhancement, use gamma = 1.0, minval = 0
* and maxval = 255.
* (4) For the normalized image pixd, each pixel is linearly mapped
* in such a way that the local threshold is equal to targetthresh.
* (5) The full width and height of the convolution kernel
* are (2 * smoothx + 1) and (2 * smoothy + 1).
* (6) This function can be used with the pixtiling utility if the
* images are too large. See pixOtsuAdaptiveThreshold() for
* an example of this.
*/
l_int32
pixThresholdSpreadNorm(PIX *pixs,
l_int32 filtertype,
l_int32 edgethresh,
l_int32 smoothx,
l_int32 smoothy,
l_float32 gamma,
l_int32 minval,
l_int32 maxval,
l_int32 targetthresh,
PIX **ppixth,
PIX **ppixb,
PIX **ppixd)
{
l_int32 w, h, d;
PIX *pixe, *pixet, *pixsd, *pixg1, *pixg2, *pixth;
PROCNAME("pixThresholdSpreadNorm");
if (ppixth) *ppixth = NULL;
if (ppixb) *ppixb = NULL;
if (ppixd) *ppixd = NULL;
if (!pixs)
return ERROR_INT("pixs not defined", procName, 1);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 8)
return ERROR_INT("pixs not 8 bpp", procName, 1);
if (!ppixth && !ppixb && !ppixd)
return ERROR_INT("no output requested", procName, 1);
if (filtertype != L_SOBEL_EDGE && filtertype != L_TWO_SIDED_EDGE)
return ERROR_INT("invalid filter type", procName, 1);
/* Get the thresholded edge pixels. These are the ones
* that have values in pixs near the local optimal fg/bg threshold. */
if (filtertype == L_SOBEL_EDGE)
pixe = pixSobelEdgeFilter(pixs, L_VERTICAL_EDGES);
else /* L_TWO_SIDED_EDGE */
pixe = pixTwoSidedEdgeFilter(pixs, L_VERTICAL_EDGES);
pixet = pixThresholdToBinary(pixe, edgethresh);
pixInvert(pixet, pixet);
/* Build a seed image whose only nonzero values are those
* values of pixs corresponding to pixels in the fg of pixet. */
pixsd = pixCreateTemplate(pixs);
pixCombineMasked(pixsd, pixs, pixet);
/* Spread the seed and optionally smooth to reduce noise */
pixg1 = pixSeedspread(pixsd, 4);
pixg2 = pixBlockconv(pixg1, smoothx, smoothy);
/* Optionally do a gamma enhancement */
pixth = pixGammaTRC(NULL, pixg2, gamma, minval, maxval);
/* Do the mapping and thresholding */
if (ppixd) {
*ppixd = pixApplyVariableGrayMap(pixs, pixth, targetthresh);
if (ppixb)
*ppixb = pixThresholdToBinary(*ppixd, targetthresh);
}
else if (ppixb)
*ppixb = pixVarThresholdToBinary(pixs, pixth);
if (ppixth)
*ppixth = pixth;
else
pixDestroy(&pixth);
pixDestroy(&pixe);
pixDestroy(&pixet);
pixDestroy(&pixsd);
pixDestroy(&pixg1);
pixDestroy(&pixg2);
return 0;
}
/*------------------------------------------------------------------*
* Adaptive background normalization (flexible adaptaption) *
*------------------------------------------------------------------*/
/*!
* pixBackgroundNormFlex()
*
* Input: pixs (8 bpp)
* sx, sy (desired tile dimensions; actual size may vary; use
* values between 3 and 10)
* smoothx, smoothy (half-width of convolution kernel applied to
* threshold array: use values between 1 and 3)
* delta (difference parameter in basin filling; use 0
* to skip)
* Return: pixd (8 bpp, background-normalized), or null on error)
*
* Notes:
* (1) This does adaptation flexibly to a quickly varying background.
* For that reason, all input parameters should be small.
* (2) sx and sy give the tile size; they should be in [5 - 7].
* (3) The full width and height of the convolution kernel
* are (2 * smoothx + 1) and (2 * smoothy + 1). They
* should be in [1 - 2].
* (4) Basin filling is used to fill the large fg regions. The
* parameter @delta measures the height that the black
* background is raised from the local minima. By raising
* the background, it is possible to threshold the large
* fg regions to foreground. If @delta is too large,
* bg regions will be lifted, causing thickening of
* the fg regions. Use 0 to skip.
*/
PIX *
pixBackgroundNormFlex(PIX *pixs,
l_int32 sx,
l_int32 sy,
l_int32 smoothx,
l_int32 smoothy,
l_int32 delta)
{
l_float32 scalex, scaley;
PIX *pixt, *pixsd, *pixmin, *pixbg, *pixbgi, *pixd;
PROCNAME("pixBackgroundNormFlex");
if (!pixs || pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs undefined or not 8 bpp", procName, NULL);
if (sx < 3 || sy < 3)
return (PIX *)ERROR_PTR("sx and/or sy less than 3", procName, NULL);
if (sx > 10 || sy > 10)
return (PIX *)ERROR_PTR("sx and/or sy exceed 10", procName, NULL);
if (smoothx < 1 || smoothy < 1)
return (PIX *)ERROR_PTR("smooth params less than 1", procName, NULL);
if (smoothx > 3 || smoothy > 3)
return (PIX *)ERROR_PTR("smooth params exceed 3", procName, NULL);
/* Generate the bg estimate using smoothed average with subsampling */
scalex = 1. / (l_float32)sx;
scaley = 1. / (l_float32)sy;
pixt = pixScaleSmooth(pixs, scalex, scaley);
/* Do basin filling on the bg estimate if requested */
if (delta <= 0)
pixsd = pixClone(pixt);
else {
pixLocalExtrema(pixt, 0, 0, &pixmin, NULL);
pixsd = pixSeedfillGrayBasin(pixmin, pixt, delta, 4);
pixDestroy(&pixmin);
}
pixbg = pixExtendByReplication(pixsd, 1, 1);
/* Map the bg to 200 */
pixbgi = pixGetInvBackgroundMap(pixbg, 200, smoothx, smoothy);
pixd = pixApplyInvBackgroundGrayMap(pixs, pixbgi, sx, sy);
pixDestroy(&pixt);
pixDestroy(&pixsd);
pixDestroy(&pixbg);
pixDestroy(&pixbgi);
return pixd;
}
/*------------------------------------------------------------------*
* Adaptive contrast normalization *
*------------------------------------------------------------------*/
/*!
* pixContrastNorm()
*
* Input: pixd (<optional> 8 bpp; null or equal to pixs)
* pixs (8 bpp, not colormapped)
* sx, sy (tile dimensions)
* mindiff (minimum difference to accept as valid)
* smoothx, smoothy (half-width of convolution kernel applied to
* min and max arrays: use 0 for no smoothing)
* Return: pixd always
*
* Notes:
* (1) This function adaptively attempts to expand the contrast
* to the full dynamic range in each tile. If the contrast in
* a tile is smaller than @mindiff, it uses the min and max
* pixel values from neighboring tiles. It also can use
* convolution to smooth the min and max values from
* neighboring tiles. After all that processing, it is
* possible that the actual pixel values in the tile are outside
* the computed [min ... max] range for local contrast
* normalization. Such pixels are taken to be at either 0
* (if below the min) or 255 (if above the max).
* (2) pixd can be equal to pixs (in-place operation) or
* null (makes a new pixd).
* (3) sx and sy give the tile size; they are typically at least 20.
* (4) mindiff is used to eliminate results for tiles where it is
* likely that either fg or bg is missing. A value around 50
* or more is reasonable.
* (5) The full width and height of the convolution kernel
* are (2 * smoothx + 1) and (2 * smoothy + 1). Some smoothing
* is typically useful, and we limit the smoothing half-widths
* to the range from 0 to 8.
* (6) A linear TRC (gamma = 1.0) is applied to increase the contrast
* in each tile. The result can subsequently be globally corrected,
* by applying pixGammaTRC() with arbitrary values of gamma
* and the 0 and 255 points of the mapping.
*/
PIX *
pixContrastNorm(PIX *pixd,
PIX *pixs,
l_int32 sx,
l_int32 sy,
l_int32 mindiff,
l_int32 smoothx,
l_int32 smoothy)
{
PIX *pixmin, *pixmax;
PROCNAME("pixContrastNorm");
if (!pixs || pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs undefined or not 8 bpp", procName, pixd);
if (pixd && pixd != pixs)
return (PIX *)ERROR_PTR("pixd not null or == pixs", procName, pixd);
if (pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pixs is colormapped", procName, pixd);
if (sx < 5 || sy < 5)
return (PIX *)ERROR_PTR("sx and/or sy less than 5", procName, pixd);
if (smoothx < 0 || smoothy < 0)
return (PIX *)ERROR_PTR("smooth params less than 0", procName, pixd);
if (smoothx > 8 || smoothy > 8)
return (PIX *)ERROR_PTR("smooth params exceed 8", procName, pixd);
/* Get the min and max pixel values in each tile, and represent
* each value as a pixel in pixmin and pixmax, respectively. */
pixMinMaxTiles(pixs, sx, sy, mindiff, smoothx, smoothy, &pixmin, &pixmax);
/* For each tile, do a linear expansion of the dynamic range
* of pixels so that the min value is mapped to 0 and the
* max value is mapped to 255. */
pixd = pixLinearTRCTiled(pixd, pixs, sx, sy, pixmin, pixmax);
pixDestroy(&pixmin);
pixDestroy(&pixmax);
return pixd;
}
/*!
* pixMinMaxTiles()
*
* Input: pixs (8 bpp, not colormapped)
* sx, sy (tile dimensions)
* mindiff (minimum difference to accept as valid)
* smoothx, smoothy (half-width of convolution kernel applied to
* min and max arrays: use 0 for no smoothing)
* &pixmin (<return> tiled minima)
* &pixmax (<return> tiled maxima)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) This computes filtered and smoothed values for the min and
* max pixel values in each tile of the image.
* (2) See pixContrastNorm() for usage.
*/
l_int32
pixMinMaxTiles(PIX *pixs,
l_int32 sx,
l_int32 sy,
l_int32 mindiff,
l_int32 smoothx,
l_int32 smoothy,
PIX **ppixmin,
PIX **ppixmax)
{
l_int32 w, h;
PIX *pixmin1, *pixmax1, *pixmin2, *pixmax2;
PROCNAME("pixMinMaxTiles");
if (!ppixmin || !ppixmax)
return ERROR_INT("&pixmin or &pixmax undefined", procName, 1);
*ppixmin = *ppixmax = NULL;
if (!pixs || pixGetDepth(pixs) != 8)
return ERROR_INT("pixs undefined or not 8 bpp", procName, 1);
if (pixGetColormap(pixs))
return ERROR_INT("pixs is colormapped", procName, 1);
if (sx < 5 || sy < 5)
return ERROR_INT("sx and/or sy less than 3", procName, 1);
if (smoothx < 0 || smoothy < 0)
return ERROR_INT("smooth params less than 0", procName, 1);
if (smoothx > 5 || smoothy > 5)
return ERROR_INT("smooth params exceed 5", procName, 1);
/* Get the min and max values in each tile */
pixmin1 = pixScaleGrayMinMax(pixs, sx, sy, L_CHOOSE_MIN);
pixmax1 = pixScaleGrayMinMax(pixs, sx, sy, L_CHOOSE_MAX);
pixmin2 = pixExtendByReplication(pixmin1, 1, 1);
pixmax2 = pixExtendByReplication(pixmax1, 1, 1);
pixDestroy(&pixmin1);
pixDestroy(&pixmax1);
/* Make sure no value is 0 */
pixAddConstantGray(pixmin2, 1);
pixAddConstantGray(pixmax2, 1);
/* Generate holes where the contrast is too small */
pixSetLowContrast(pixmin2, pixmax2, mindiff);
/* Fill the holes (0 values) */
pixGetDimensions(pixmin2, &w, &h, NULL);
pixFillMapHoles(pixmin2, w, h, L_FILL_BLACK);
pixFillMapHoles(pixmax2, w, h, L_FILL_BLACK);
/* Smooth if requested */
if (smoothx > 0 || smoothy > 0) {
smoothx = L_MIN(smoothx, (w - 1) / 2);
smoothy = L_MIN(smoothy, (h - 1) / 2);
*ppixmin = pixBlockconv(pixmin2, smoothx, smoothy);
*ppixmax = pixBlockconv(pixmax2, smoothx, smoothy);
}
else {
*ppixmin = pixClone(pixmin2);
*ppixmax = pixClone(pixmax2);
}
pixDestroy(&pixmin2);
pixDestroy(&pixmax2);
return 0;
}
/*!
* pixSetLowContrast()
*
* Input: pixs1 (8 bpp)
* pixs2 (8 bpp)
* mindiff (minimum difference to accept as valid)
* Return: 0 if OK; 1 if no pixel diffs are large enough, or on error
*
* Notes:
* (1) This compares corresponding pixels in pixs1 and pixs2.
* When they differ by less than @mindiff, set the pixel
* values to 0 in each. Each pixel typically represents a tile
* in a larger image, and a very small difference between
* the min and max in the tile indicates that the min and max
* values are not to be trusted.
* (2) If contrast (pixel difference) detection is expected to fail,
* caller should check return value.
*/
l_int32
pixSetLowContrast(PIX *pixs1,
PIX *pixs2,
l_int32 mindiff)
{
l_int32 i, j, w, h, d, wpl, val1, val2, found;
l_uint32 *data1, *data2, *line1, *line2;
PROCNAME("pixSetLowContrast");
if (!pixs1 || !pixs2)
return ERROR_INT("pixs1 and pixs2 not both defined", procName, 1);
if (pixSizesEqual(pixs1, pixs2) == 0)
return ERROR_INT("pixs1 and pixs2 not equal size", procName, 1);
pixGetDimensions(pixs1, &w, &h, &d);
if (d != 8)
return ERROR_INT("depth not 8 bpp", procName, 1);
if (mindiff > 254) return 0;
data1 = pixGetData(pixs1);
data2 = pixGetData(pixs2);
wpl = pixGetWpl(pixs1);
found = 0; /* init to not finding any diffs >= mindiff */
for (i = 0; i < h; i++) {
line1 = data1 + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w; j++) {
val1 = GET_DATA_BYTE(line1, j);
val2 = GET_DATA_BYTE(line2, j);
if (L_ABS(val1 - val2) >= mindiff) {
found = 1;
break;
}
}
if (found) break;
}
if (!found) {
L_WARNING("no pixel pair diffs as large as mindiff", procName);
pixClearAll(pixs1);
pixClearAll(pixs2);
return 1;
}
for (i = 0; i < h; i++) {
line1 = data1 + i * wpl;
line2 = data2 + i * wpl;
for (j = 0; j < w; j++) {
val1 = GET_DATA_BYTE(line1, j);
val2 = GET_DATA_BYTE(line2, j);
if (L_ABS(val1 - val2) < mindiff) {
SET_DATA_BYTE(line1, j, 0);
SET_DATA_BYTE(line2, j, 0);
}
}
}
return 0;
}
/*!
* pixLinearTRCTiled()
*
* Input: pixd (<optional> 8 bpp)
* pixs (8 bpp, not colormapped)
* sx, sy (tile dimensions)
* pixmin (pix of min values in tiles)
* pixmax (pix of max values in tiles)
* Return: pixd always
*
* Notes:
* (1) pixd can be equal to pixs (in-place operation) or
* null (makes a new pixd).
* (2) sx and sy give the tile size; they are typically at least 20.
* (3) pixmin and pixmax are generated by pixMinMaxTiles()
* (4) For each tile, this does a linear expansion of the dynamic
* range so that the min value in the tile becomes 0 and the
* max value in the tile becomes 255.
* (5) The LUTs that do the mapping are generated as needed
* and stored for reuse in an integer array within the ptr array iaa[].
*/
PIX *
pixLinearTRCTiled(PIX *pixd,
PIX *pixs,
l_int32 sx,
l_int32 sy,
PIX *pixmin,
PIX *pixmax)
{
l_int32 i, j, k, m, w, h, wt, ht, wpl, wplt, xoff, yoff;
l_int32 minval, maxval, val, sval;
l_int32 *ia;
l_int32 **iaa;
l_uint32 *data, *datamin, *datamax, *line, *tline, *linemin, *linemax;
PROCNAME("pixLinearTRCTiled");
if (!pixs || pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs undefined or not 8 bpp", procName, pixd);
if (pixd && pixd != pixs)
return (PIX *)ERROR_PTR("pixd not null or == pixs", procName, pixd);
if (pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pixs is colormapped", procName, pixd);
if (!pixmin || !pixmax)
return (PIX *)ERROR_PTR("pixmin & pixmax not defined", procName, pixd);
if (sx < 5 || sy < 5)
return (PIX *)ERROR_PTR("sx and/or sy less than 5", procName, pixd);
pixd = pixCopy(pixd, pixs);
iaa = (l_int32 **)CALLOC(256, sizeof(l_int32 *));
pixGetDimensions(pixd, &w, &h, NULL);
data = pixGetData(pixd);
wpl = pixGetWpl(pixd);
datamin = pixGetData(pixmin);
datamax = pixGetData(pixmax);
wplt = pixGetWpl(pixmin);
pixGetDimensions(pixmin, &wt, &ht, NULL);
for (i = 0; i < ht; i++) {
line = data + sy * i * wpl;
linemin = datamin + i * wplt;
linemax = datamax + i * wplt;
yoff = sy * i;
for (j = 0; j < wt; j++) {
xoff = sx * j;
minval = GET_DATA_BYTE(linemin, j);
maxval = GET_DATA_BYTE(linemax, j);
if (maxval == minval) { /* this is bad */
/* fprintf(stderr, "should't happen! i,j = %d,%d, minval = %d\n",
i, j, minval); */
continue;
}
ia = iaaGetLinearTRC(iaa, maxval - minval);
for (k = 0; k < sy && yoff + k < h; k++) {
tline = line + k * wpl;
for (m = 0; m < sx && xoff + m < w; m++) {
val = GET_DATA_BYTE(tline, xoff + m);
sval = val - minval;
sval = L_MAX(0, sval);
SET_DATA_BYTE(tline, xoff + m, ia[sval]);
}
}
}
}
for (i = 0; i < 256; i++)
if (iaa[i]) FREE(iaa[i]);
FREE(iaa);
return pixd;
}
/*!
* iaaGetLinearTRC()
*
* Input: iaa (bare array of ptrs to l_int32)
* diff (between min and max pixel values that are
* to be mapped to 0 and 255)
* Return: ia (LUT with input (val - minval) and output a
* value between 0 and 255)
*/
static l_int32 *
iaaGetLinearTRC(l_int32 **iaa,
l_int32 diff)
{
l_int32 i;
l_int32 *ia;
l_float32 factor;
PROCNAME("iaaGetLinearTRC");
if (!iaa)
return (l_int32 *)ERROR_PTR("iaa not defined", procName, NULL);
if (iaa[diff] != NULL) /* already have it */
return iaa[diff];
if ((ia = (l_int32 *)CALLOC(256, sizeof(l_int32))) == NULL)
return (l_int32 *)ERROR_PTR("ia not made", procName, NULL);
iaa[diff] = ia;
if (diff == 0) { /* shouldn't happen */
for (i = 0; i < 256; i++)
ia[i] = 128;
}
else {
factor = 255. / (l_float32)diff;
for (i = 0; i < diff + 1; i++)
ia[i] = (l_int32)(factor * i + 0.5);
for (i = diff + 1; i < 256; i++)
ia[i] = 255;
}
return ia;
}