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Introduction to the TIFF Documentation | |
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Introduction to the TIFF Documentation | |
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The following definitions are used throughout this documentation. | |
They are consistent with the terminology used in the TIFF 6.0 specification. | |
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<DT><I>Sample</I> | |
<DD>The unit of information stored in an image; often called a | |
channel elsewhere. Sample values are numbers, usually unsigned | |
integers, but possibly in some other format if the SampleFormat | |
tag is specified in a TIFF | |
<DT><I>Pixel</I> | |
<DD>A collection of one or more samples that go together. | |
<DT><I>Row</I> | |
<DD>An Nx1 rectangular collection of pixels. | |
<DT><I>Tile</I> | |
<DD>An NxM rectangular organization of data (or pixels). | |
<DT><I>Strip</I> | |
<DD>A tile whose width is the full image width. | |
<DT><I>Compression</I> | |
<DD>A scheme by which pixel or sample data are stored in | |
an encoded form, specifically with the intent of reducing the | |
storage cost. | |
<DT><I>Codec</I> | |
<DD>Software that implements the decoding and encoding algorithms | |
of a compression scheme. | |
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In order to better understand how TIFF works (and consequently this | |
software) it is important to recognize the distinction between the | |
physical organization of image data as it is stored in a TIFF and how | |
the data is interpreted and manipulated as pixels in an image. TIFF | |
supports a wide variety of storage and data compression schemes that | |
can be used to optimize retrieval time and/or minimize storage space. | |
These on-disk formats are independent of the image characteristics; it | |
is the responsibility of the TIFF reader to process the on-disk storage | |
into an in-memory format suitable for an application. Furthermore, it | |
is the responsibility of the application to properly interpret the | |
visual characteristics of the image data. TIFF defines a framework for | |
specifying the on-disk storage format and image characteristics with | |
few restrictions. This permits significant complexity that can be | |
daunting. Good applications that handle TIFF work by handling as wide | |
a range of storage formats as possible, while constraining the | |
acceptable image characteristics to those that make sense for the | |
application. | |
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Last updated: $Date: 1999/08/09 20:21:21 $ | |
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