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.
14032639
Sliding-window packetization for unequal loss protection based multiple description coding
Unequal loss protection (ULP) for transmitting embedded bitstream over packet erasure networks has been extensively studied. However, most of the existing works focused on rate-distortion optimization of individual encoding unit, e.g., a group of pictures (GOP), which may lead to noticeable video quality variations due to varying channel conditions. In this paper, a novel sliding-window packetization scheme is proposed, which combat bursty packet loss through GOP interleaving. Two levels of rate allocation are introduced: intra-GOP rate allocation minimizes the distortion of individual GOP, and provides hybrid FEC/retransmission packet loss recovery; while inter-GOP rate allocation intends to reduce video quality fluctuations by adaptively allocating bandwidth according to video signal characteristics. Through this way, more consistent video quality can be achieved under various packet loss probability, as verified by our experimental results.
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.
40327612
Dual-plan bandwidth smoothing for layer-encoded video
Traditional bandwidth smoothing techniques can be naturally supported by the renegotiated constant bit rate (RCBR) service model, but renegotiation failure in RCBR may cause buffer underflow and interrupt the playback of video. To address this concern, a novel dual-plan bandwidth smoothing (DBS) scheme is proposed in this paper by taking advantage of the SNR scalability of layer-encoded video. Upon renegotiation failure, the proposed scheme can adaptively discard certain enhancement layers to guarantee continuous video playback at the original frame rate. Experiments are carried out to demonstrate the validity of the proposed scheme. The impacts of renegotiation interval, granularity of enhancement layers, and playback buffer size on resulted video quality are also studied. From the simulation results, it is shown that the performance of the RCBR-based DBS scheme can be improved by 1) reducing the minimum time gap of renegotiation interval; 2) employing multilayer video encoding with finer granularity; and/or 3) increasing the playback buffer size.
29981324
Accurate optical flow estimation using adaptive scale-space and 3D structure tensor
Computing optical flow for image sequences is often an essential step to many image processing and computer vision applications. In this paper, a novel, unified optical flow estimation method is developed for simultaneously tackling the aperture problem and multiple motions, and consequently, yielding more accurate optical flow estimation. By integrating Gaussian scale-space with 3D structure tensor, the estimation difficulty encountered in multiple motions resulting from multiple video objects has been handled reasonably well. The obtained normal flow is then treated separately from the real flow, by further applying the least-squares estimation, with the assist of the automatic scale selection mechanism, to produce the estimated real flow. Our proposed automatic scale selection for spatial scale-space is developed from the viewpoint of numerical stability, and the condition number is exploited for adaptively choosing local scales (window sizes). For performance evaluation, we adopted the angular error as the quantitative measurement and used several benchmark image sequences. Experimental results show that the accuracy of our optical flow estimation method is superior to several leading algorithms.
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