The model proposed by Chan and Vese using one level set function is not able to obtain sub-objects in the object because one level set can only represent one object and one background via its sign.To solve the problem

an algorithm for multi-layer object segmentation based on Chan-Vese(C-V) model is proposed.Firstly

an idea for multi-layer object segmentation is proposed after the analysis of the C-V model.Secondly

a key technique

named as the technique of painting background

is developed and proved following the theory of the simultaneous brightness contrast.Thirdly

the proposed algorithm is presented using the proposed technique and the C-V model.Finally

experimental results show that the proposed algorithm is especially effective for the detection of the sub-objects with weak boundaries in the object.