Interpolation filter for error diffused bilevel images

Summary form only given. This paper presents an interpolation method for error diffused bilevel images without inverse half toning and re-half toning. The interpolation method of our approach is realized in the form of a cascade connection of an upsampler and a linear interpolation post filter. We discuss the frequency domain characteristic of upsampled error diffused images and impose five conditions to the interpolation post filter that can produce enlarged bilevel images. We show that there exists a linear post filter that satisfies the five conditions and it can yield higher resolution pseudo-continuous tone images from error diffused bilevel images. We also proposed an adaptive edge sharpening for the proposed interpolation method and show the interpolation results of the error diffused images that are obtained with Floyd-Steinberg and Jarvis kernel.