there is described an image processing apparatus that converts - bit monochromatic image data of a single channel into n - bit color display image data of three channels or more , based on predetermined correlations . the apparatus includes luminance and chromaticity calculating sections to calculate luminance and chromaticity information corresponding to each of monochrome signal values ; a signal value determining section to determine each combination of plural - channel color signal values represented by the n - bit color display image data , based on the luminance and chromaticity information , so that each combination of the plural - channel color signal values corresponds to each of the monochrome signal values ; and a correlation establishing section to establish the predetermined correlations between the - bit monochromatic image data and the n - bit color display image data , so that each combination of the plural - channel color signal values and each of the monochrome signal values are correlated with each other .