Oriented Smoothness Aided Harmonic Gradient Vector Flow for Active Contours

A new external force called oriented smoothness aided harmonic gradient vector flow (OSAHGVF) is proposed for active contours. This proposed method incorporate the oriented smoothness borrowed from optical flow into the harmonic gradient vector flow (HGVF) model, therefore, there are three terms, i.e., the harmonic term, the oriented smoothness term and the fidelity term, in the model. Two weighting functions are utilized to regularize the effect of the first two terms respectively, aiming at extending the capture range and preserving object boundaries simultaneously. Experiments and comparisons with the gradient vector flow (GVF) are presented to show the advantages of this approach, including superior noise robustness, edge-preserving and C-shape concavity convergence.