| /*****************************************************************************/ |
| // Copyright 2006 Adobe Systems Incorporated |
| // All Rights Reserved. |
| // |
| // NOTICE: Adobe permits you to use, modify, and distribute this file in |
| // accordance with the terms of the Adobe license agreement accompanying it. |
| /*****************************************************************************/ |
| |
| /* $Id: //mondo/dng_sdk_1_4/dng_sdk/source/dng_temperature.cpp#1 $ */ |
| /* $DateTime: 2012/05/30 13:28:51 $ */ |
| /* $Change: 832332 $ */ |
| /* $Author: tknoll $ */ |
| |
| #include "dng_temperature.h" |
| |
| #include "dng_xy_coord.h" |
| |
| /*****************************************************************************/ |
| |
| // Scale factor between distances in uv space to a more user friendly "tint" |
| // parameter. |
| |
| static const real64 kTintScale = -3000.0; |
| |
| /*****************************************************************************/ |
| |
| // Table from Wyszecki & Stiles, "Color Science", second edition, page 228. |
| |
| struct ruvt |
| { |
| real64 r; |
| real64 u; |
| real64 v; |
| real64 t; |
| }; |
| |
| static const ruvt kTempTable [] = |
| { |
| { 0, 0.18006, 0.26352, -0.24341 }, |
| { 10, 0.18066, 0.26589, -0.25479 }, |
| { 20, 0.18133, 0.26846, -0.26876 }, |
| { 30, 0.18208, 0.27119, -0.28539 }, |
| { 40, 0.18293, 0.27407, -0.30470 }, |
| { 50, 0.18388, 0.27709, -0.32675 }, |
| { 60, 0.18494, 0.28021, -0.35156 }, |
| { 70, 0.18611, 0.28342, -0.37915 }, |
| { 80, 0.18740, 0.28668, -0.40955 }, |
| { 90, 0.18880, 0.28997, -0.44278 }, |
| { 100, 0.19032, 0.29326, -0.47888 }, |
| { 125, 0.19462, 0.30141, -0.58204 }, |
| { 150, 0.19962, 0.30921, -0.70471 }, |
| { 175, 0.20525, 0.31647, -0.84901 }, |
| { 200, 0.21142, 0.32312, -1.0182 }, |
| { 225, 0.21807, 0.32909, -1.2168 }, |
| { 250, 0.22511, 0.33439, -1.4512 }, |
| { 275, 0.23247, 0.33904, -1.7298 }, |
| { 300, 0.24010, 0.34308, -2.0637 }, |
| { 325, 0.24702, 0.34655, -2.4681 }, |
| { 350, 0.25591, 0.34951, -2.9641 }, |
| { 375, 0.26400, 0.35200, -3.5814 }, |
| { 400, 0.27218, 0.35407, -4.3633 }, |
| { 425, 0.28039, 0.35577, -5.3762 }, |
| { 450, 0.28863, 0.35714, -6.7262 }, |
| { 475, 0.29685, 0.35823, -8.5955 }, |
| { 500, 0.30505, 0.35907, -11.324 }, |
| { 525, 0.31320, 0.35968, -15.628 }, |
| { 550, 0.32129, 0.36011, -23.325 }, |
| { 575, 0.32931, 0.36038, -40.770 }, |
| { 600, 0.33724, 0.36051, -116.45 } |
| }; |
| |
| /*****************************************************************************/ |
| |
| void dng_temperature::Set_xy_coord (const dng_xy_coord &xy) |
| { |
| |
| // Convert to uv space. |
| |
| real64 u = 2.0 * xy.x / (1.5 - xy.x + 6.0 * xy.y); |
| real64 v = 3.0 * xy.y / (1.5 - xy.x + 6.0 * xy.y); |
| |
| // Search for line pair coordinate is between. |
| |
| real64 last_dt = 0.0; |
| |
| real64 last_dv = 0.0; |
| real64 last_du = 0.0; |
| |
| for (uint32 index = 1; index <= 30; index++) |
| { |
| |
| // Convert slope to delta-u and delta-v, with length 1. |
| |
| real64 du = 1.0; |
| real64 dv = kTempTable [index] . t; |
| |
| real64 len = sqrt (1.0 + dv * dv); |
| |
| du /= len; |
| dv /= len; |
| |
| // Find delta from black body point to test coordinate. |
| |
| real64 uu = u - kTempTable [index] . u; |
| real64 vv = v - kTempTable [index] . v; |
| |
| // Find distance above or below line. |
| |
| real64 dt = - uu * dv + vv * du; |
| |
| // If below line, we have found line pair. |
| |
| if (dt <= 0.0 || index == 30) |
| { |
| |
| // Find fractional weight of two lines. |
| |
| if (dt > 0.0) |
| dt = 0.0; |
| |
| dt = -dt; |
| |
| real64 f; |
| |
| if (index == 1) |
| { |
| f = 0.0; |
| } |
| else |
| { |
| f = dt / (last_dt + dt); |
| } |
| |
| // Interpolate the temperature. |
| |
| fTemperature = 1.0E6 / (kTempTable [index - 1] . r * f + |
| kTempTable [index ] . r * (1.0 - f)); |
| |
| // Find delta from black body point to test coordinate. |
| |
| uu = u - (kTempTable [index - 1] . u * f + |
| kTempTable [index ] . u * (1.0 - f)); |
| |
| vv = v - (kTempTable [index - 1] . v * f + |
| kTempTable [index ] . v * (1.0 - f)); |
| |
| // Interpolate vectors along slope. |
| |
| du = du * (1.0 - f) + last_du * f; |
| dv = dv * (1.0 - f) + last_dv * f; |
| |
| len = sqrt (du * du + dv * dv); |
| |
| du /= len; |
| dv /= len; |
| |
| // Find distance along slope. |
| |
| fTint = (uu * du + vv * dv) * kTintScale; |
| |
| break; |
| |
| } |
| |
| // Try next line pair. |
| |
| last_dt = dt; |
| |
| last_du = du; |
| last_dv = dv; |
| |
| } |
| |
| } |
| |
| /*****************************************************************************/ |
| |
| dng_xy_coord dng_temperature::Get_xy_coord () const |
| { |
| |
| dng_xy_coord result; |
| |
| // Find inverse temperature to use as index. |
| |
| real64 r = 1.0E6 / fTemperature; |
| |
| // Convert tint to offset is uv space. |
| |
| real64 offset = fTint * (1.0 / kTintScale); |
| |
| // Search for line pair containing coordinate. |
| |
| for (uint32 index = 0; index <= 29; index++) |
| { |
| |
| if (r < kTempTable [index + 1] . r || index == 29) |
| { |
| |
| // Find relative weight of first line. |
| |
| real64 f = (kTempTable [index + 1] . r - r) / |
| (kTempTable [index + 1] . r - kTempTable [index] . r); |
| |
| // Interpolate the black body coordinates. |
| |
| real64 u = kTempTable [index ] . u * f + |
| kTempTable [index + 1] . u * (1.0 - f); |
| |
| real64 v = kTempTable [index ] . v * f + |
| kTempTable [index + 1] . v * (1.0 - f); |
| |
| // Find vectors along slope for each line. |
| |
| real64 uu1 = 1.0; |
| real64 vv1 = kTempTable [index] . t; |
| |
| real64 uu2 = 1.0; |
| real64 vv2 = kTempTable [index + 1] . t; |
| |
| real64 len1 = sqrt (1.0 + vv1 * vv1); |
| real64 len2 = sqrt (1.0 + vv2 * vv2); |
| |
| uu1 /= len1; |
| vv1 /= len1; |
| |
| uu2 /= len2; |
| vv2 /= len2; |
| |
| // Find vector from black body point. |
| |
| real64 uu3 = uu1 * f + uu2 * (1.0 - f); |
| real64 vv3 = vv1 * f + vv2 * (1.0 - f); |
| |
| real64 len3 = sqrt (uu3 * uu3 + vv3 * vv3); |
| |
| uu3 /= len3; |
| vv3 /= len3; |
| |
| // Adjust coordinate along this vector. |
| |
| u += uu3 * offset; |
| v += vv3 * offset; |
| |
| // Convert to xy coordinates. |
| |
| result.x = 1.5 * u / (u - 4.0 * v + 2.0); |
| result.y = v / (u - 4.0 * v + 2.0); |
| |
| break; |
| |
| } |
| |
| } |
| |
| return result; |
| |
| } |
| |
| /*****************************************************************************/ |