Optimization of morphological structuring elements for angiogram enhancement
Keith M. Andress, David L. Wilson · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1991
Morphological image processing (MORPH) is a useful technique for angiogram enhancement. We compare the technique with digital subtraction angiography (DSA) by viewing the filtering operation as the approximation of the mask image in DSA processing. Viewing the enhancement process in this manner allows us to judge the performance of the filter by measuring the RMS error between the DSA and MORPH images. By computing the error for a wide variety of structuring element (SE) shapes and sizes, we are able to pick the optimal SE as the one with minimum error. Two shapes of SEs are under investigation: ellipsoidal and an approximation to this, called the separable ellipsoid, obtained by dilating two one-dimensional elliptical SEs aligned in the row and column directions. The separable ellipsoid gives comparable results to those of the ellipsoid and allows a significant reduction in the computational time.