OBJECTIVETo modify the level set method for precise and fast segmentation of B-type ultrasound image lesions.

METHODSBased on the best of region level set method, entropy in the information theory was introduced into image processing to define a dynamic weighting factor that responded to the gradient change of the local gray levels to evaluate the dynamic degree of driven force on each pixel on the contour to the target and background areas. The dynamic weighting factors were reconciled into the regional level set model and led the contour to deform and move during the iterations. As lesion segmentation was classified as local segmentation of a specific area, the calculation was restrained to the local sphere abide by the contour, which greatly reduced the calculation complex.

RESULTSExperiments on B-type ultrasound images showed improved results of the proposed method with a better accuracy and less time consumption compared with several current level set methods.

CONCLUSIONLevel set method reconciled with dynamic weighting factor allows a better evaluation of the lesion contour pixels, and the local calculation strategy results in an enhanced segmentation efficiency.