Realization of multi-point segmented one-setp correction medthod in contact image sensor scanner

A new non-uniformity correction method used in contact image sensor (CIS) scanner is presented, and it could rapidly and efficiently accomplish non-uniformity correction of CIS scanners color image and eliminate the color difference of CIS. To obtain uniform color images, the multi-point segmented one-step method is adopted in calibration process and FPGA is used for correcting. For the resolution of CIS scanner up to 1200 dpi, pattern paper is only captured once to complete the calibration of all color space and correction is accomplished during the acquiring image process, and it takes only 0.125 microsecond. The practical application results show that the output images uniformity is about ten times promotion than that before correction and about three times than that with traditional two-point method.