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