When images are presented on media or stored in devices that offer low amplitude resolution, dithering is often performed to maintain the illusion of continuous color or grayscale. Artifacts associated with low amplitude resolution, such as false contours, are thereby mitigated. I n this project, we developed a new color inverse dithering system designed for low-cost implementation. In our implementation, we employ an extremely small set of one-dimensional filters to minimize complexity and storage requirements.
Edge detection is based on simple pattern matching.
The need for multipliers is eliminated by using bit replication for increasing the bit-depth, and by using lookup tables with relatively small numbers of entries for filtering. We have found that our inverse dithering system can restore to a significant degree a dithered image to its original form. It is especially effective for graphics and synthetic images. The following is an example of the inverse dithering system in action. The images on the lower row are blowups.