Detection of protein spots from complex region on real gel image

Protein spot detection is an important step in gel image analysis. The results of spot detection may substantially influence gel image analysis. One of the most challenges of spot detection is separation of spots from complex region, where spots are overlapped and saturated. In this paper, we propose a spot detection algorithm which is capable of detection of spots from complex region. The proposed approach is realized by using European distance transform and centroid marker based watershed. Firstly, we apply a standard marker-controlled watershed algorithm to roughly segment the gel image into multiple regions. For those complex region containing several overlapped spots, we estimate spot centroids through a European distance transform. The estimated centroids are then served as spot markers in marker-controlled watershed algorithm to make a fine spot segmentation. Experimental results show the proposed method can obtain high detection performance in real gel images, and can accurately identify overlapped spots in complex region, when compared to other popular spot detection methods.