The microscopic image of protoplasm somatic cells typically has blurred boundaries and inhomogeneous object regions.Therefore

it is difficult to segment the cells using traditional methods. First

because the protoplasm cell is round

the circular prior knowledge is added to the fast level set method and then a new circle dependent fast level set segmentation method is proposed. Then

to solve the problem of segmentation for multi protoplasm somatic cells

the pre-segmentation is used before using the fast multi-level set method based on circle information. Furthermore

a new fast level-set method

which is based on the histogram

is proposed to get a better result for the pre-segmentation. The eight-chain code tracking method and the randomized Hough transform for circle detection are used to divide object region resulting from pre-segmentation respectively for multi-cells and multi-clustered cells. Finally

experimental results show that the new method proposed in this paper can deal well with the problem of segmentation for protoplasm somatic cells.