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In this paper, we propose a new design method of general weighted median filters admitting negative weights for enhancement of images degraded by additive impulsive noise. The general weighted median (GWM) filters are already proposed as frequency selective nonlinear filters. Nevertheless, no one considers how to apply the GWM filters for enhancing degraded images. To enhance images degraded by additive noise, preferable frequency response is varied greatly with positions of window in images. Therefore, GWM filters with fixed weights are not preferable in image processing. Proposed method consists with three steps. At first, we divide block in sliding windows of filters into some number of classes according to difference of spectral characteristics. Second, we optimize some number of GWM filters to have proper frequency response in each class of block. At last, the GWM filters switched in each class are used for enhancement of images. To prepare the GWM filters in each class, the proposed filtering method is better than the GWM filters with fixed weights. Through some simulations, we show the above efficiency of the proposed filters comparing to the original WM filters and linear filters. The proposed method has the robustness for impulsive noise contamination and the frequency selective filtering property. more...

This paper presents new methods for partitioning a set of multi-view images into 3-D regions corresponding to objects in the scene in order to parse raw multi-view data into a 3-D region based structured representation. For this purpose, color, position, and disparity information at each pixel are incorporated as an attributes vector into the segmentation process. We propose three methods, all of which are based on K-means clustering algorithm. The first method is sensitive to the estimation error of disparity at each pixel, as it is formulated assuming that the estimated disparity is accurate. We solve this problem in the second method by prohibiting estimated disparity from being used for calculating the distance between attributes vectors. Finally, a third method is proposed to reduce the calculation cost of the segmentation process. As each 3-D region has one-to-one correspondence to an object or surface in the scene, 3-D region based structured representation of multi-view images is useful and powerful for data compression, view interpolation, structure recovery, and so on. The experimental results show the potential applicability of the method to the next-generation 3-D image communication system.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. more...

We introduce in the present paper a fast 3D fractal encoding method based on tree compression and achieving good compression ratio at very low bit rate. The algorithm is also open to transposition on the space of wavelet coefficients.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. more...

This paper addresses a problem of extraction of the structural motion information for compact image sequence representation. In order to extract a meaningful scene structure from image sequence, global motion and region shape of moving objects are taken into consideration. Firstly, intraframe segmentation is carried out with edges that are detected from zero-crossings of a wavelet transform, and local motions are estimated using a gradient-based method. Moving regions are then extracted using the local motion based on the intraframe segmentation. Secondly, moving regions are roughly separated into the region of the moving objects based on probabilistic clustering with mixture models using the optical flow and the image intensity for each region of the intraframe segmentation. Motion segmentation can finally be obtained by iterated estimation of affine motion parameters and region reassignment according to a criterion using Gauss-Newton iterative optimization algorithm.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. more...