Nayer Wanas, Mahmoud R. El-Sakka, and Mohamed S. Kamel, "Enhancement of Vessel Contours in Retinal Angiograms", IEEE Canadian Journal on Electrical and Computer Engineering, Vol 25, No. 3, pp. 99-103, July 2000.
Accurate and automatic assessment of angiograms has been sought as a powerful diagnostic tool in medical analysis, such as in diabetic retinopathy. These retinal angiograms images are characterized by poor local contrast. Applications of existing edge detection algorithms yield unsatisfactory results. In this paper, a set of cascaded linear directional filters is used to better enhance edges. Results show improvement in visual quality of the images.