An economic color printing algorithm using approximate-K

This paper proposes 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(C, M and Y) to print all the pixels for color images, and it makes color printing cost 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 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 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. From our experimental results, printing a color image using our algorithm needs only 77% of the original price in average.