SINTEF has for the client AKVA Group investigated possibilities for automatic identification and segmentation of individual fish in schools of fish based on short video sequences with stereo cameras. Advanced Variational and PDE (Partial Differential Equations) based image processing and segmentation techniques have been used, utilizing the mutual information in the two stereo cameras and in sequences of video, and by including prior models for fish shape probabilities.
S. Clausen, K. Greiner, O. Andersen, K.-A. Lie, H. Schulerud, and T. Kavli. Automatic segmentation of overlapping fish using shape priors. Lecture Notes in Comput. Sci., Vol. 4522/2007, pp. 11-20, 2007. DOI: 10.1007/978-3-540-73040-8_2
Examples of fish segmentations with overlap between different fish.