Hybrid Resolution Enhancement Technique based on LookUp Tables

摘要

Recently, performance of electrophotographic printers has been significantly improved. Image quality and printing speed are major factors that determine performance of electrophotographic printers. Increase in the spatial resolution and multi-bit printing capability would result in the improved quality of printed images. However, when halftoning (or multi-toning) is performed by the printer driver, transmission time from computer to printer and the memory size required to store the image data will be increased. In order to reduce the size of image data transmitted from computer to printer, a LUT based method to enhance both of the spatial and bit-depth resolution is presented in this paper. The proposed LUTs are designed in advance using the training samples and stored at printer. When the haftoned image data is received from the computer, number of black pixels in 4x4 window is compared with number of black pixels in the 4 neighboring windows to select LUT. Spatial and bit-depth resolution are then simultaneously increased by applying the selected LUT. Various factors affecting performance of a LUT based resolution enhancement are analyzed.