Patent ID: 7580561

Claim:
An image processing apparatus configured to reproduce pixels representative of a colour image from groups of colour component signal samples representing the image, each of said groups representing two of said pixels and comprising two input luminance values, one for each pixel, and first and second input chrominance values formed by averaging first and second chrominance values for each pixel, said apparatus comprising: a de-compressing processor configured to receive said groups of colour component signal samples and to generate reproduced pixels, each comprising three colour component values, and a detail detection processor configured to detect whether one of said first and second pixels is representative of substantially white or substantially black and the other of said pixels is not representative of substantially white or substantially black, and if so, arranging for said de-compressing processor, to assign to first and second chrominance values for the one of said first and second pixels representing substantially white or black the value of zero, to assign to first and second chrominance values for the other of said first and second pixels, not representing substantially white or black, twice the value of the first and second input chrominance values respectively, and to reproduce the three colour components of each pixel from the corresponding input luminance value and the assigned first and second chrominance values, and otherwise to reproduce the three colour components of each pixel from the corresponding input luminance value in combination with the first and second input chrominance values.