Lossless compression of pre-press images using a novel colour decorrelation technique

Most existing lossless image compression schemes operate on grey-scale imag es. However, in the case of colour images, higher compression ratios can be achieved by exploiting inter-colour redundancies. A new lossless colour tr ansform is presented, based on the KLT. This transform removes redundancies in the colour representation of each pixel and can be combined with many e xisting compression schemes. In this paper it is combined with a prediction scheme that exploits spatial redundancies. The results proposed in this pa per show that the colour transform typically saves about a half to two bits per pixel, compared to a purely predictive scheme. (C) 1999 Pattern Recogn ition Society. Published by Elsevier Science Ltd. All rights reserved.