Digital Filtering and Edge Detection Algorithms for Nuclear Medicine Images

Several edge detection algorithms were compared. The nearest neighbor algorithm (NNA) was shown to be superior to the other methods. The NNA was then used to evaluate the effects of nine common digital filters. It was shown that high pass filters improve relative constrast at the expense of edge definition. Furthermore, low pass filters only improve edge detection in the limit of low signal to noise ratios. Finally, all filters tested significantly distorted area relationships and perimeter contours.