Splitting touching cells based on concave-point and improved watershed algorithms

Splitting touching cells is important for medical image processing and analysis system. In this paper, a novel strategy is proposed to separate ellipse-like or circle-like touching cells in which different algorithms are used according to the concave-point cases of touching domains. In the strategy, a concave-point extraction and contour segmentation methods for cells in series and in parallel are used for the images with distinct concave points, and an improved watershed algorithm with multi-scale gradient and distance transformation is adopted for the images with un-distinct or complex concave points. In order to visualize each whole cell, ellipse fitting is used to process the segments. Experimental results show that, for the cell images with distinct concave points, both of the two algorithms can achieve good separating results, but the concave-point based algorithm is more efficient. However, for the cell images with unobvious or complex concave points, the improved watershed based algorithm can give satisfying segmenting results.