The three elements of the LSAC model are model building, level set expression and numerical algorithm. Model establishment is to determine the evolution equation of the active contour curve, which is the basis for the LSAC model to realize image segmentation. The level set expression is to implicitly express the active contour curve with the zero level of the level set function. The numerical algorithm is used to solve the evolution equation of the active contour curve, determine the final position of the curve on the image (the position corresponds to the image segmentation result), and the solution process corresponds to the evolution process of the curve on the image definition domain (including displacement, deformation, splitting, etc.). merger, etc.). Different configurations of model elements determine the performance of the model such as accuracy, efficiency, and robustness.