(a) MDI intensitygram obtained May 17, 2000 at 11:11 UT, (b) sunspot segmentation map, which was achieved by applying Eq. (1). This is the result of the first stage of the initial sunspot segmentation. (c) sunspot segmentation map, which was achieved by applying Eq. (2). This is the result of the second stage of the initial sunspot segmentation. The segmentation map from the second stage shows further detection of sunspots.