Abstract:The inverse halftone algorithm of gray image with Loop-Up Table is extended to the color images, though the correlation of three-channel in color images is considered, with the halftone value as the index value to add continuous value to the mapping table simply, not only makes the data in the map not true, but also makes the inverse halftone image quality influenced by the halftone noise and reduces the quality. Therefore, puts forward a kind of Look-Up Table color image inverse halftone algorithm with color block storage. The method first matches the color value of pixel between continuous image and halftone image, then determines the match ratio. If the match ratio is equal or similar, saves the continuous value into the look-up map with the half tone value as index; if not similar, stores the continuous value in a substitute table, as a basis of the estimation of look-up table. Experiments show that the visual effect of image inverse halftone Look-Up Table with color block storage is better than that of color image inverse halftone of lookup table, and the signal-to-noise ratio of peak value, the degree of color reproduction and the color trend are higher than the value from the lookup table method.