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<HTML> <HEAD> <TITLE> Introduction to the TIFF Documentation </TITLE> </HEAD> <BODY BGCOLOR=white> <FONT FACE="Arial, Helvetica, Sans"> <H1> <IMG SRC=images/strike.gif WIDTH=128 HEIGHT=100 ALIGN=left HSPACE=6> Introduction to the TIFF Documentation </H1> <P> The following definitions are used throughout this documentation. They are consistent with the terminology used in the TIFF 6.0 specification. <DL> <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. </UL> <P> 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. <P> <HR> Last updated: $Date: 1999/08/09 20:21:21 $ </BODY> </HTML>