The Design Of PCNN Image Noise Filter Based On FPGA

With the development of embedded systems, the requirement of hardware-based image processing grows rapidly. Embedded systems have a flexible feature in cutting hardware and software. And hardware implementation possesses the advantages of high-speed and real-time. It is possible that image processing algorithms are implemented in hardware, because FPGA has flexible programmable, reconfigurable performance, high integration and high-speed processing capability. In recent years, FPGA-based image processing becomes an important research direction in the field of image processing.Image filter algorithms for impulse noise based on PCNN and the median filter has been one of the jobs in our laboratory for many years. Compared to the implementation of Matlab software, the implementation of FPGA hardware platform possesses high-speed and good performance and other advantages. In this paper, the PCNN impulse noise filter is implemented on the FPGA platform.In this paper, the design of the filter mainly includes PCNN noise detect module, median filtering module, image display module and control module for read and write(in Flash). The following issues are resolved during the process of FPGA hardware implementation of the filter.(1) The filter based on PCNN and the median filter for impulse noise is implemented in FPGA hardware platform. The noise points are mainly detected by the classification property of PCNN. Then the noise points are filtered by the median filter.(2) When the impulse noises are detected in FPGA, the noises for high- intensity (salt noise) is processed by using a higher initial threshold value, and the noises can be located after firing a few times (1-2 times); while the noises for low-intensity (pepper noise) is detected, only converting low-intensity to high- intensity, the method of processing is the same. So, the number of iterations is largely decreased.(3) It combines the Flash controller for reading and writing with the VGA display controller. And the output of the filter is connected to VGA display output module, so the output results can be displayed on the monitor. At the same time, the results are saved in the flash memory,So that they will be analysed and processed later.