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In this paper, we propose an analysis of fractional pixels which are interpolated from integer pixels using hierarchical linear FIR filters based on a differential structure of sub-pixels. In order to improve a video quality under a limited bitrate, most of video codecs employs fractional pixels (or samples) in a process of motion compensation or motion estimation. Even though the fractional pixels...
The unique requirements imposed by contemporary video communication applications promote the rise of the distributed video coding paradigm, which offers flexible complexity allocation and error resilience combined with competitive compression performance. This work proposes a novel Wyner-Ziv video coding scheme, performing hash-based motion estimation at the decoder. Subsequently, maximum likelihood...
New method improving B-slice prediction is proposed. By combining the optical flow concept and high accuracy gradients evaluation we construct the algorithm which allows pixel-wise refinement of motion. This approach does not require any signaling for decoder. According to tests with WQVGA sequences bit-saving of 2%-6% can be achieved using this tool.
The hybrid coding method combining the predictive coding with the orthogonal transformation and the quantization is mainly used recently. This paper proposes a new hybrid parallel Intra Coding based on interpolative prediction which uses correlations between neighboring pixels, including non-causal pixels. In order to get high prediction performance, the optimal quantizing scheme, which is used to...
The prediction step is a very important part of hybrid video codecs. In this contribution, a novel spatio-temporal prediction algorithm is introduced. For this, the prediction is carried out in two steps. Firstly, a preliminary temporal prediction is conducted by motion compensation. Afterwards, spatial refinement is carried out for incorporating spatial redundancies from already decoded neighboring...
Currently, depth sequences generated by automatic depth estimation suffer from the temporal inconsistency problem. Estimated depth values of some objects vary in adjacent frames, whereas the objects actually remain on the same depth planes. These temporal depth errors significantly impair the visual quality of the synthesized virtual view as well as the coding efficiency of the depth sequences. Since...
In this paper, we propose a fast graph cut (GC) algorithm for disparity estimation. Two accelerating techniques are suggested: one is the early termination rule, and the other is prioritizing the α-β swap pair search order. Our simulations show that the proposed fast GC algorithm outperforms the original GC scheme by 210% in the average computation time while its disparity estimation quality is almost...
Many existing multi-view video coding techniques remove inter-viewpoint redundancy by applying disparity compensation in conventional video coding frameworks, e.g., H264/MPEG4. However, conventional methodology works ineffectively as they ignore the special features of the inter-view-point disparity. This paper proposes a framework using virtual plane (VP) for multi-view image compression, such that...
View synthesis using depth maps is a well-known technique for exploiting the redundancy between multi-view videos. In this paper, we deal with the bitrates of view synthesis at the decoder side of FTV that would use compressed depth maps and views. Both inherent depth estimation error and coding distortion would degrade synthesis quality. The focus is to reduce bitrates required for generating the...
One important recent application of image registration has been in the estimation of global motion parameters for object-based video coding. A limitation of current global motion estimation approaches is the additional complexity of the gradient-descent optimization that is typically required to calculate the optimal set of global motion parameters. In this paper we propose a new low-complexity algorithm...
In this paper, we propose an intra-prediction system that is both parallel friendly and with high coding efficiency. This is achieved by combining a novel prediction strategy that reduces serial dependencies and a novel, multi-directional and adaptive prediction system. The resulting technique is compared with state-of-the-art ITU-T H.264/MPEG-4 AVC. We observe a 2× and 8× increase in parallelism...
H.264/AVC employs intra prediction to reduce spatial redundancy between neighboring blocks. Different directional prediction modes are used to cater diversified video content. Although it achieves quite high coding efficiency, it is desirable to analyze its drawbacks in the existing video coding standard, since it allows us to design better ones. Basically, even after intra prediction, the residue...
Multi-view video coding exploits inter-view redundancies to compress the video streams and their associated depth information. These techniques utilize disparity estimation techniques to obtain disparity vectors (DVs) across different views. However, these methods contribute to the majority of the computational power needed for multi-view video encoding. This paper proposes a solution for fast disparity...
Side information plays a key role in the performance of a Distributed Video Coding (DVC) system. However, the generation of side information often relies on complex motion estimation/interpolation operation. The correlation between the source data and the side information, sometimes referred as virtual channel, is also very difficult to model accurately. In this paper, we propose a bitwise prediction...
Simplified visualisation of the fuel spray developing process of varied ethanol content in an open spray by the liquid injection technique. For obtaining spray characteristics in the liquid, the visualisation principles were based on spray penetrations images. The video imaging and schlieren technique have been used to investigate the spray development and behaviours at different injection time defined...
Video compression algorithms are time consuming processes. A key part of video compression algorithms which is also time consuming is motion estimation (ME) and computation of motion vectors (MVs). During this process, a series of candidate blocks should be searched to find the best motion vectors. In this paper, we propose a method for reducing the motion estimation process time. The idea of our...
Error concealment at the video decoder is to recover erroneous picture region based on correctly decoded region in the same frame or the neighboring frames. However, the existing error concealment methods cannot give satisfactory result in some situations, e.g. when a whole frame is lost. In this paper, we propose a novel joint forward-backward concealment (JFBC) method. The key observation is that,...
In this paper we introduce a novel concept for Intra coding of pictures especially suitable for representing smooth image segments. Traditional block based transform coding methods cause visually annoying blocking artifacts for image segments with gradually changing smooth content. The proposed solution overcomes this drawback by defining a fully continuous surface of sample values approximating the...
In this paper, a mathematical model is proposed to estimate the distortion caused by random packet losses for multi-view video transmission. Based on the study of multi-view video coding, the proposed model takes into account the disparity/motion compensation which relates the channel-induced distortion in the current frame with that in the previous frame or the adjacent view, and allows for any motion-compensated...
A modified orthogonal search (OS) algorithm via gradient descent is proposed for fast motion estimation (ME). Gradient descent method, a first-order optimization algorithm in machine learning, is employed in video coding to reduce the ME time for coding performance enhancement. An improved OS algorithm is created in our proposed method. Through this method, the number of search points is reduced significantly...
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