Color Scanner Characterization with Scan Targets of Different Media Types and Printing Mechanisms

摘要

Due to the increasing popularity and affordability of color imaging devices, color characterization for these devices becomes an important subject. In other words, a set of color profile(s) needs to be generated for each device to transform the device dependent color space to a device independent one. This paper will concentrate on color characterization of scanners. Up to now, most scanner characterization has been optimized for photographic materials only. However, the color characterization inevitably depends on the media type and the printing mechanism that produced the target. In this work, a color scanner was characterized based on six different scan target types. For each target type, a color profile from RGB to CIELAB space was generated using polynomial regression method and a series of color conversions were conducted using color profiles optimized for itself as well as other target types. The accuracy of color transformation was evaluated. Results proved that to achieve the best color reproduction quality, it's necessary to characterize a color scanner based on specific scan target type. Considering the system level memory limitation, a compromise could be made without great quality degradation, using an average or unified profile for some target types. Nevertheless, a scanner should at least have two profiles: one for photo and the other for halftoning printing process.