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<TITLE>
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Introduction to the TIFF Documentation
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<BODY BGCOLOR=white>
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<FONT FACE="Arial, Helvetica, Sans">
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<H1>
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<IMG SRC=images/strike.gif WIDTH=128 HEIGHT=100 ALIGN=left HSPACE=6>
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Introduction to the TIFF Documentation
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</H1>
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<P>
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The following definitions are used throughout this documentation.
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They are consistent with the terminology used in the TIFF 6.0 specification.
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<DL>
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<DT><I>Sample</I>
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<DD>The unit of information stored in an image; often called a
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channel elsewhere. Sample values are numbers, usually unsigned
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integers, but possibly in some other format if the SampleFormat
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tag is specified in a TIFF
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<DT><I>Pixel</I>
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<DD>A collection of one or more samples that go together.
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<DT><I>Row</I>
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<DD>An Nx1 rectangular collection of pixels.
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<DT><I>Tile</I>
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<DD>An NxM rectangular organization of data (or pixels).
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<DT><I>Strip</I>
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<DD>A tile whose width is the full image width.
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<DT><I>Compression</I>
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<DD>A scheme by which pixel or sample data are stored in
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an encoded form, specifically with the intent of reducing the
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storage cost.
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<DT><I>Codec</I>
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<DD>Software that implements the decoding and encoding algorithms
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of a compression scheme.
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</UL>
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<P>
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In order to better understand how TIFF works (and consequently this
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software) it is important to recognize the distinction between the
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physical organization of image data as it is stored in a TIFF and how
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the data is interpreted and manipulated as pixels in an image. TIFF
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supports a wide variety of storage and data compression schemes that
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can be used to optimize retrieval time and/or minimize storage space.
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These on-disk formats are independent of the image characteristics; it
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is the responsibility of the TIFF reader to process the on-disk storage
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into an in-memory format suitable for an application. Furthermore, it
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is the responsibility of the application to properly interpret the
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visual characteristics of the image data. TIFF defines a framework for
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specifying the on-disk storage format and image characteristics with
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few restrictions. This permits significant complexity that can be
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daunting. Good applications that handle TIFF work by handling as wide
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a range of storage formats as possible, while constraining the
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acceptable image characteristics to those that make sense for the
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application.
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<P>
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<HR>
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Last updated: $Date: 1999/08/09 20:21:21 $
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</HTML>
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