Fig. 2.

Probability maps $\mathit{\phi }$ obtained using, from left to right, no preferred orientation, Hessian-based analysis and structure tensor-based initialisation. The response of a vesselness filter [10] was used as initial saliency measurement for the first two cases. The approaches using the response of the vesselness filter are more sensible to fine structures. The structure tensor approach fails to detect small vessels, but has a strong response in large vessels