Crosfield Electronics Limited

Anthony J Johnson

Lindsay W MacDonald

Paul E Franklin

Ronnier Luo

A method and apparatus for processing data representing an image in a first color space suitable for controlling a first image output device. The apparatus comprises a processor (11, 14, 17) for reversibly transforming the image into a perceptual color space defined by lightness, colorfulness and hue components, and for modifying the lightness, colorfulness and hue components of the image in accordance with a predetermined algorithm so that all colors in the image fall within the gamut of a second image output device; and a store for storing data defining the modified and unmodified lightness, colorfulness and hue components.

Image processor for output devices which transforms data into acceptable

Methods of electronically enhancing one or more color components (C, Y, M) which together represent the chromatic components of a pixel of an image are described. The methods comprise subtracting from each color component respective quantities which when combined correspond to a grey level (4) to generate reduced color components. These reduced color components are then multiplied by a factor and the modified reduced color components are then added back to the subtracted quantities or to the original color components to generate enhanced color components (13,14), whereby the factor is chosen such that the hue of the original pixel is not substantially changed after enhancement. In one method, the magnitude of the maximum reduced color component is determined and a factor is chosen which is related to the determined magnitude. In another method, the color components are ranked in order of magnitude and compared to derive two equivalent color component values. The magnitude of the maximum equivalent color component is determined and the factor chosen is related to the determined magnitude of a maximum equivalent color component.

Growing community of inventors

Bedfordshire, United Kingdom

Anthony J Johnson