A hybrid scheme for low bit-rate coding of stereo images

Abstract

In this paper, we propose a hybrid scheme to implement an object driven, block based algorithm to achieve low bit-rate compression of stereo image pairs. The algorithm effectively combines the simplicity and adaptability of the existing block based stereo image compression techniques with an edge/contour based object extraction technique to determine appropriate compression strategy for various areas of the right image. Unlike the existing object-based coding such as MPEG-4 developed in the video compression community, the proposed scheme does not require any additional shape coding. Instead, the arbitrary shape is reconstructed by the matching object inside the left frame, which has been encoded by standard JPEG algorithm and hence made available at the decoding end for those shapes in right frames. Yet the shape reconstruction for right objects incurs no distortion due to the unique correlation between left and right frames inside stereo image pairs and the nature of the proposed hybrid scheme. Extensive experiments carried out support that significant improvements of up to 20% in compression ratios are achieved by the proposed algorithm in comparison with the existing block-based technique, while the reconstructed image quality is maintained at a competitive level in terms of both PSNR values and visual inspections.

Integration of fuzzy logic and structure tensor towards mammogram contrast enhancement

“…In practice, s is normally determined on empirical basis. However, some principles can be followed to provide a roughly guideline for the effect of its selection [17]. This can be summarised as follows: † Lower s values will detect more edges or contours, and hence presents high fluctuations inside the image; † Higher s values produce less edges or contours, leading to useless results failing to characterise the edge structure and information; † In our work, we control the s selection within the range of [0.5, 2.5].…”

Stereo image compression using wavelet coefficients morphology

“…This is repeated within a predefined window length and the DV is estimated for the best match [4]. The block-matching algorithm may also be applied on the objects that appear after the object contour extraction in the two images [5] or on the subbands of a wavelet decomposed stereo image pair, in a hierarchical way [6]. The most commonly used similarity measures are the mean-square error (MSE) and the mean absolute error (MAE), which is generally preferred due to its simplicity.…”

A wavelet implementation of the pioneering block-based disparity compensated predictive coding algorithm for stereo image pair compression

“…The culmination of research in this direction resulted in the recent standardization of JPEG-2000 [7] and wavelet domain implementations of MPEG-4 video coding standard. As most stereo image and sequence compression techniques that have been proposed in literature are based on DCT-based technologies [2,3,6,[8][9][10]15,[19][20][21], currently there exists a trend in transfer of stereo imaging technology to DWT-based techniques.…”

“…Thus at present, efficient algorithms that are capable of coding and transmitting (storing) stereo images and image sequences are attracting significant research efforts from the stereo imaging research community. To this extent various coding algorithms based on block, object-and region-based predictive coding techniques have been reported in literature [1][2][3][4]6,[8][9][10]15,17,[19][20][21].…”