35556766
Error concealment for image transmission by multiscale Markov random field modeling
Transmission of visual data over communication channels introduces serious fidelity problems. The paper proposes an efficient error concealment algorithm for the image transmitted as encoded bitstreams. The proposed method introduces a multiscale Markov random field (MMRF) to model the original image. The established MMRF model is consequently employed to interpolate the missing blocks in the observing data via maximum a posterior (MAP) estimation. Compared with the conventional spatial interpolation scheme, this algorithm offers significant improvements on both subjective and objective qualities of the recovered image.
2569570
Practical issues of dynamic bit allocation in multimedia source compression
Owing to various emerging multimedia applications which create enormous amount of data traffic over limited channel bandwidth, dynamic bit allocation plays a significant role on achieving robust and/or optimum source coding performance. In this paper, we focus on pixel-based and perceptual-based dynamic bit allocations which have been widely exploited in many source coding algorithms and international audio/visual compression standards as well. Many fundamental facts of human auditory system have been effectively exploited in perceptual-based bit allocation for speech and audio signals. On the contrary, pixel-based bit allocation which is widely used in image and video coding has certain practical issues required to be addressed. We highlight these observed concerns, present an unified and optimum solution, and recommend a future direction.
37284906
Novel video signal processor with VLIW-controlled SIMD architecture
In this paper, we present a novel video signal processor (VSP) architecture, named VS-VSP, which combines the very long instruction word (VLIW) control with the single instruction multiple data (SIMD) processing technology. The SIMD architecture provides high performance for the computation-intensive tasks, and the VLIW control introduces satisfactory flexibility to the whole system. In addition, a hierarchical memory organization is employed in VS-VSP to tackle the high data-bandwidth requirements in the video signal processing application. The proposed VS-VSP architecture can be exploited for implementing a variety of video coding algorithms efficiently.
6762785
A new diamond search algorithm for fast block-matching motion estimation
Based on the study of motion vector distribution from several commonly used test image sequences, a new diamond search (DS) algorithm for fast block-matching motion estimation (BMME) is proposed in this paper. Simulation results demonstrate that the proposed DS algorithm greatly outperforms the well-known three-step search (TSS) algorithm. Compared with the new three-step search (NTSS) algorithm, the DS algorithm achieves close performance but requires less computation by up to 22% on average. Experimental results also show that the DS algorithm is better than the four-step search (4SS) and block-based gradient descent search (BBGDS), in terms of mean-square error performance and required number of search points.
1533691
Generalized optimum dynamic bit allocation scheme for source compression
Dynamic bit allocation directly impacts the overall coding performance in block transform (e.g., DCT, Hadamard, etc.) coding, subband coding, and wavelet coding. In very low bit rate coding (such as the evolving MPEG-4 standard), additional factors impacting the bit allocation process need to be identified and properly exploited to achieve optimal coding performance. In the paper, a generalized optimum dynamic bit allocation algorithm is presented. The algorithm is based on the Shannon rate-distortion bound and a weighted distortion criterion using a Lagrange multiplier optimization technique. The results look promising for applications in real-time multimedia communications.<<ETX>>
5852047
Using eigencolor normalization for illumination-invariant color object recognition
Abstract Color is one of salient features for color object recognition, however, the colors of object images sensitively depend on scene illumination. To overcome the lighting dependency problem, a color constancy or color normalization method has to be used. This paper presents a color image normalization method, called eigencolor normalization, which consists of two phases as follows. First, the compacting method, which was originally used for compensating the adverse effect due to shape distortion for 2-D planar objects, is exploited for 3-D color space to make the color distribution less correlated and more compact. Second, the compact color image is further normalized by rotating the histogram to align with the reference axis computed. Consequently, the object colors are transformed into a new color space, called eigencolor space, which reflects the inherent colors of the object and is more invariant to illumination changes. Experimental results show that our eigencolor normalization method is superior to other existing color constancy or color normalization schemes on achieving more accurate color object recognition.
5064603
The ascending star subgraph decomposition of some star forests