Abstract
This paper, following the previous one, treats some improvements of the stereo matching method that has been proposed by the authors. The major effort is bent to find and process occlusions using a narrow band-pass filter. The obtained results are as follows:
(1) In the author's matching structure, stereo images are subdivided to overlapping patch pairs which make processed units for matching. Correlation windows around the grid points which are located on a left patch are correlated to the respective search windows on the right one. The previous paper showed that for finding the position of occlusions median filtering of measured x-parallaxes is useful. But matching convergency and precision is still insufficient in the marginal area of patches. Especially in case that occlusions appear in the margin, matching tends to wander. To keep the precision uniform, it is suggested in this paper that the grid points included in the margin, the width of which is possible maximum occlusion width plus the width of the median filter, should be discarded.
(2) It is proved that unstableness of matching in the presence of projective distortions or ther noises comes from the fact that images contain wide band range of frequencies. Hence the images are filtered with a narrow band-pass filter beforehand to raise up matching convergency and precision. In particular the so-called Laplacian of Gaussian filter has preferable properties for this purpose.
