Embedded color error diffusion

We present an algorithm for image browsing systems that embeds a color halftone into another color halftone of a higher bit depth, as well as embedding a grayscale or binary halftone into a grayscale or color halftone. The benefit of this algorithm is that a low bit-depth halftone can be directly obtained from a higher bit-depth halftone for printing of progressive transmission simply by masking one or more bits off of the color halftone. The embedding can be done in any bit of the output depending on the organization of the image palettes, although the most significant or the least significant bits are most convenient. The embedding algorithm that we describe requires the use of scalar quantizers and ordered vector quantizers. We present several methods for color palette organization, or binary index assignment, to be used in conjunction with the embedded color error diffusion algorithm