Image Border Management for FPGA Based Filters

Most of the literature on image filtering using FPGAs focuses on the normal case when the window is completely within the image. The exception - when the window is partly off the edge of the image - is rarely considered. If not managed appropriately, handling these exceptions can take up more resources than the main operation. Efficient techniques are presented that manage the image borders by reusing the logic for the standard case. A technique is described for overlapping the priming and flushing phases at the end of row and end of frame that reduce the overhead in time critical applications.