Economic approximate-K color printing algorithm

Abstract

This article describes a novel scheme to save the usage of ink or toner by an approximate-K algorithm for color printers. Existing printers use the mixtures of three color toners (Cyan, Magenta and Yellow) to print all the pixels for color images, and it makes color printing 4---4.5 times more expensive than monochromic printing. Since human eyes are not sensitive to distinguish neighboring colors in the color space, we can use the K (blackK) toner to replace the colors close to gray-scale. We can then reduce the ink usage without affecting the image visual qualities. We use the saturation in the HSV (hue, saturation, value) color model to discover the near gray-scale pixels and transform those pixels to gray level. We then evaluate the objective image quality using the PSNR (Peak Signal Noise Ratio) and use the DSCQS (Double Stimulus Continuous Quality Scale) as the subjective evaluation method. From our experimental results, printing a color image using our algorithm needs only 84 % of the original price in average.