A method for improving the detection of low-contrast and narrow width vessels comprising combining matched-filter responses with that of directional filter bank. A given vessel is characterized by having an elongated structure with a specific width and direction. Matched filters are designed in the form of elliptical second-order Gaussian derivatives at various scales, catering for vessels of widely varying widths. On the other hand, the directional filter bank helps in identifying the orientation of the vessels. Thus, combining both in complementary manner results is an improved response for vessels with varying width and varying direction. Results comparing this hybrid approach to matched filter and directional filter bank alone show substantial improvements both qualitatively and quantitatively.
