Colour image data processing device - uses comparison of colour image data with defined range to detect monochrome pixels

摘要

The data processing device has a monochrome pixel detector (106) with a generator providing threshold values from one of the 3 sets of colour image data, defining the upper and lower limits of a range within which the other 2 sets of colour image data lie, when the examined pixel is a monochrome pixel. The second colour image data sets are compared with this range to provide a monochrome pixel output signal when they lie within the upper and lower limits. The monochrome pixel detector (106) is proceeded by a colour correction stage (105) converting red, green and blue colour image data into cyan, magenta, yellow and black colour-image data. USE - For colour copier improving copy quality of both colour and black and white copies.