Nuclear detection in 4D microscope images using enhanced probability map of top-ranked intensity-ordered descriptors

Nuclear detection in embryos is an indispensable process for quantitative analysis of the development of multicellular organisms. Due to the overlap in the distribution of nuclear and cytoplasmic intensities and the large variation even within the same type of tissues of different embryos, it is difficult to separate nuclear regions from the surrounding cytoplasmic region in differential interference contrast (DIC) microscope image. This study explores a discriminative representation of texton around a fixed pixel, called Top-ranked Intensity-ordered Descriptor (TRIOD), which is prospected to distinguish the smoothed texture in nucleus from the irregular texture in cytoplasm containing yolk granules. Then, a probability process is employed to model nuclear TRIOD prototypes, and the enhanced nuclear probability map can be constructed with the TRIODs of all pixels in a DIC microscope image. Finally, distance regularized level set method is applied to refine the initial localization by simply thresholding on the enhanced probability map. Experimental results show that the proposed strategy can give much better performance for segmentation of nuclear regions than the conventional strategies.