Apparatus and method for color transformation

DETAILED DESCRIPTION The present invention seeks to provide a color transformation apparatus and technique which require relatively little memory but which result in relatively high transformation accuracy.
The apparatus and methods of the present invention are useful in any color transformation application, such as color reading, color writing, digital color modification, and combinations of these, where color reading is defined as transforming an analog representation of a color image into a digital representation thereof, color writing is defined as transforming a digital representation of a color image into an analog representation thereof and digital color modification is defined as modifying a first digital representation of a color image, thereby to obtain a second digital representation of a color image, with or without use of a real-time display screen.
In the present discussion, the term "color image" is not intended to exclude images which are gradations of a single tone such as black and white images, and the following definitions are employed: Analog representation of a color image: A representation of a color image which resembles or is analogous to the color image itself or which is perceivable by the human eye as a color image.
The representation may appear upon any substrate such as a transparency, photograph, CRT display, or printed page.
Digital representation of a color image: A representation of a color image which is expressed in discrete symbols such as numerical symbols.
For example, a digital file including a plurality of numerical values corresponding to a plurality of pixels into which the color image has been divided, each such numerical value representing some aspect pertaining to the colored appearance of the corresponding pixel.
According to the technique of the present invention, an input data space is partitioned into a plurality of input data subspaces which are normally not of equal size.
The input data in each of the plurality of subspaces addresses a corresponding one of a plurality of LUTs which may be of equal size but typically are not of equal resolution