Efficient compression of motion-compensated sub-images with Karhunen-Loeve transform in three-dimensional integral imaging

An approach to highly enhance the compression efficiency of the integral images by applying the Karhunen-Loeve transform (KLT) algorithm to the motion-compensated sub-images is proposed. The sub-images transformed from the elemental images picked-up from the three-dimensional (3D) object might represent the different perspectives of the object. Thus, the similarity among the sub-images gets better than that among the elemental images, so that an improvement of compression efficiency of the sub-images could be obtained. However, motion vectors occurred among the sub-images might result in an additional increase of image data to be compressed. Accordingly, in this paper, motion vectors have been estimated and compensated in all sub-image in advance. Then the KLT algorithm was applied to these motion-compensated sub-images for compression. It is shown from some experimental results that compression efficiency of the proposed method has been improved up to 24.44%, 40.62%, respectively, on the average compared to that of the conventional KLT compression method and that of the JPEG.     

Enhanced compression of integral images by combined use of residual images and MPEG-4 algorithm in three-dimensional integral imaging

In this paper, we proposed a novel approach to enhance the compression rate of integral images by combined use of the residual images generated from the sub-images and the MPEG-4 algorithm. In the proposed method, elemental images picked up from a three-dimensional object are transformed into sub-images, and these sub-images are sequentially rearranged with a spiral scanning topology and the first sub-image is assigned as the reference image. Then, by sequentially computing the differences between the reference image and other consecutive sub-images, a sequence of residual images is generated. Here, the residual images together with the reference image are modeled as the consecutive video frames just like a conventional moving picture. Finally, these residual images are compressed with the MPEG-4 algorithm. Experimental results show that compression efficiency of the proposed method has been improved up to 61.56% as compared to those of the JPEG-based compression scheme and up to 151.54% as compared to those of the conventional method averagely.