Role of prefiltering in unsupervised video segmentation

In this study, we address the problem of prefiltering before segmentation. Prefiltering is quite important since it simplifies the data, producing flat zones without computing the contour information (Salembier and Pardas, 1994). Morphological filters with reconstruction restore the contour of the components. However, covered and uncovered areas in moving objects may be connected during the reconstruction process. In this case, open-close by partial reconstruction filters remove those artifacts in the background. After that, the contours of the regions can be located by the watershed algorithm. Although the number of resulting regions at the end of watershed with open-close by partial reconstruction is more than local averaging, applying a premerging by comparing the difference of mean gray values to these regions results in less number and greater-sized regions. Therefore, open-close filtering makes merging of more regions possible.