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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.+ −
+ − <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.+ −
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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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