Measuring vascular bundle size. Each row is a different individual vascular bundle. A small, medium, and large bundle was selected for presentation. The left column shows the original unprocessed color image. The center column shows the processed grayscale image enhanced by a homomorphic filtering step. The right column shows the level contours of a 2D Gaussian distribution fit to enhanced grayscale map. The outermost ring is taken as a measure of the size of the bundle.