Abstract: The present invention is a method and apparatus for digitally controlling the output of multiple laser diodes in a system that forms a plurality of scan lines in a Raster Output Scanning (ROS) system. Output of the laser diodes is digitally controlled by monitoring and controlling the bias and run level power for each of the laser diodes. The system employs predetermined, controllable biasing currents to increase the resolution of the exposure current and thereby accurately control the output power of each of the multiple laser diodes, and to provide a fixed exposure level that is detectable by a low-cost start-of-scan detector.

Abstract: The present invention is a method for the color correction of digital images that have been compressed. In a preferred embodiment, aspects of the color correction are carried out on the compressed image data to improve computational efficiency. One of a number of alternative methods is employed to accomplish the color correction on lossy or losslessly compressed images. The color transformation process accomplishes color correction on compressed image data in conjunction with compression or decompression operations. A second, simplified phase of the color correction may be applied subsequently to the decompressed image data in certain embodiments.

Abstract: The present invention is a method and apparatus for the enhancement of 1 bit per pixel image signals to produce a multiple-bit per pixel form. A binary input image is passed through a plurality of filters to generate level slices. The filters are stack filters implemented as look-up table or template-based filters, morphological filters, or any similar binary-to-binary filters that could be used to generate level slices. Each of the N-1 filters is used to produce the slices, where N is the number of possible gray-scale levels desired in the output image. Once the slices are generated, the resulting binary image data therein is recombined, by adding or stacking, to produce the desired multiple-bit per pixel output.