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| 2 | <HEAD>
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| 3 | <TITLE>
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| 4 | Introduction to the TIFF Documentation
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| 5 | </TITLE>
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| 6 | </HEAD>
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| 7 | <BODY BGCOLOR=white>
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| 8 | <FONT FACE="Arial, Helvetica, Sans">
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| 9 | <H1>
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| 10 | <IMG SRC=images/strike.gif WIDTH=128 HEIGHT=100 ALIGN=left HSPACE=6>
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| 11 | Introduction to the TIFF Documentation
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| 12 | </H1>
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| 13 |
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| 14 |
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| 15 | <P>
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| 16 | The following definitions are used throughout this documentation.
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| 17 | They are consistent with the terminology used in the TIFF 6.0 specification.
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| 18 |
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| 19 | <DL>
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| 20 | <DT><I>Sample</I>
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| 21 | <DD>The unit of information stored in an image; often called a
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| 22 | channel elsewhere. Sample values are numbers, usually unsigned
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| 23 | integers, but possibly in some other format if the SampleFormat
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| 24 | tag is specified in a TIFF
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| 25 | <DT><I>Pixel</I>
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| 26 | <DD>A collection of one or more samples that go together.
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| 27 | <DT><I>Row</I>
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| 28 | <DD>An Nx1 rectangular collection of pixels.
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| 29 | <DT><I>Tile</I>
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| 30 | <DD>An NxM rectangular organization of data (or pixels).
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| 31 | <DT><I>Strip</I>
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| 32 | <DD>A tile whose width is the full image width.
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| 33 | <DT><I>Compression</I>
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| 34 | <DD>A scheme by which pixel or sample data are stored in
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| 35 | an encoded form, specifically with the intent of reducing the
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| 36 | storage cost.
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| 37 | <DT><I>Codec</I>
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| 38 | <DD>Software that implements the decoding and encoding algorithms
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| 39 | of a compression scheme.
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| 40 | </UL>
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| 41 |
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| 42 | <P>
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| 43 | In order to better understand how TIFF works (and consequently this
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| 44 | software) it is important to recognize the distinction between the
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| 45 | physical organization of image data as it is stored in a TIFF and how
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| 46 | the data is interpreted and manipulated as pixels in an image. TIFF
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| 47 | supports a wide variety of storage and data compression schemes that
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| 48 | can be used to optimize retrieval time and/or minimize storage space.
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| 49 | These on-disk formats are independent of the image characteristics; it
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| 50 | is the responsibility of the TIFF reader to process the on-disk storage
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| 51 | into an in-memory format suitable for an application. Furthermore, it
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| 52 | is the responsibility of the application to properly interpret the
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| 53 | visual characteristics of the image data. TIFF defines a framework for
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| 54 | specifying the on-disk storage format and image characteristics with
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| 55 | few restrictions. This permits significant complexity that can be
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| 56 | daunting. Good applications that handle TIFF work by handling as wide
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| 57 | a range of storage formats as possible, while constraining the
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| 58 | acceptable image characteristics to those that make sense for the
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| 59 | application.
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| 60 |
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| 61 |
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| 62 | <P>
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| 63 | <HR>
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| 64 |
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| 65 | Last updated: $Date: 1999/08/09 20:21:21 $
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| 66 |
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| 67 | </BODY>
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| 68 | </HTML>
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