COLOUR SIGNAL PROCESSING

摘要

A method of adjusting the N components of an N component colour signal (such as the 3 components of an RGB colour signal) with respect to colour temperature of illuminating light when imaging a coloured subject, comprising the step of computing the difference between each of the components of the colour signal for different temperatures of illuminating light, using an algorithm based on the spectral sensitivity of the imaging means and Planck's equation defining black body illumination to obtain N components whose values are independent of the colour temperature of the illuminating light. Normalisation of the adjusted values renders the values independent of intensity of illumination and can also reduce the processing time for further processing of the signals. A technique for compensating for gamma correction which is commonly built in cameras, is disclosed.