\input zb-basic \input zb-ioport \iteman{io-port 06100360} \itemau{Zhang, Peng; Zhong, Jun; Guo, Anming; Peng, Qiang} \itemti{Improved image preprocessing algorithm based on FPGA.} \itemso{J. Comput. Appl. 31, No. 6, 1706-1708 (2011).} \itemab Summary: In order to preprocess the monitoring image, the image preprocessing was studied. Grayscale and binarization algorithm are highly complex, difficult to achieve and cost large computation. The weighted average method was redesigned, of which the floating-point computation was simplified to fixed-point for the benefit of achieving FPGA. An improved function based on Otsu algorithm was proposed and it was proved to be equivalent to Otsu algorithm. Moreover, the preprocessing algorithm was easy to be realized via hardware. After the Verilog programming, the algorithm was simulated on Matlab and ModelSim. The result demonstrates that the new algorithm is effective and achievable. Therefore, the design can be used as a preprocessing module of a real-time image processing system. As a result, it will save lots of time for the computations after preprocessing. \itemrv{~} \itemcc{} \itemut{Field Programmable Gate Array (FPGA); image preprocessing; binarization; Otsu algorithm; iteration} \itemli{doi:10.3724/SP.J.1087.2011.01706} \end