An FPGA-based 3D image processor with median and convolution filters for real-time applications
Sharmila Venugopal, Carlos R. Castro‐Pareja, Omkar S. Dandekar · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2005
Median Filtering and Convolution operations constitute 60-70% of the preprocessing operations performed on digital images. Software implementations of 3D filters in general-purpose processors do not match the speed requirements for real-time performance. Field Programmable Gate Arrays (FPGAs) support reconfigurable architectures that are sufficiently flexible to implement more than one operation in the existing hardware, yielding higher speed for real-time execution. We present a linear systolic array architecture for median filtering, that implements bit-serial searching and majority voting. The unique arrangement of line delay units endows parallelism to the bit-serial median finding algorithm. Convolution operation, based on the fast embedded multiplier units in the FPGA and an optimized Carry Save Adder array is also presented. The application of the above designs to 3D image preprocessing is described. A voxel rate of 220MHz is achieved for median filtering and 277MHz for convolution operation.