<title></title>

Introduction to the TIFF Documentation

<font face="Arial, Helvetica, Sans"></font>

Introduction to the TIFF Documentation

The following definitions are used throughout this documentation.

They are consistent with the terminology used in the TIFF 6.0 specification.

Sample

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

Pixel

A collection of one or more samples that go together.

Row

An Nx1 rectangular collection of pixels.

Tile

An NxM rectangular organization of data (or pixels).

Strip

A tile whose width is the full image width.

Compression

A scheme by which pixel or sample data are stored in

  an encoded form, specifically with the intent of reducing the

  storage cost.

Codec

Software that implements the decoding and encoding algorithms

  of a compression scheme.

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.

Last updated: $Date: 1999/08/09 20:21:21 $