Method for compensating for differing sensor spectral responses or sensitivities in a CCD scanner device

A colour CCD image reading device 9 is oriented with respect to an object 7 to be read in order to optimise illumination in, for example, the blue wavelength. The lower sensitivity blue CCD sensor 9a is positioned closest to the illumination source 50. Pixel data for each line is read, generated in reverse order and/or re-phased by a line controller (11, Figure 2), so as to compensate for offset linear sensors on the CCD device. As shown in Figure 2, line controller 11 receives colour data values from CCD 9, a pixel clock signal and stored data from SRAM 14.