The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Efficient and robust wireless video delivery is an enabling technology for various applications. The existing wireless video transmission scheme has the cliff effect and it cann't gracefully adapt to channel variations. In this paper, we introduce a pseudo-analog wireless video transmission improvements and design in the hardware. Comparing with the traditional transmission, the linear processing...
The paper uses EMD to construct a new transformation matrix to improve the original matrix coding algorithm and proposes a new video steganography algorithm:Improved Matrix Encoding (IME). The proposed algorithmretains the advantages of EMD and matrix encoding that it can greatly reduce the modifications of embed carrier to achieve a high embedding efficiency under the conditions of same embedding...
An algorithm for adaptive orthogonal filter bank trees for encoding of motion-compensated frame differences is presented. The proposed method is based on the hybrid video coding scheme. For frame prediction, overlapped block motion compensation is applied. The prediction error frames are encoded using an adaptive wavelet packet algorithm based on a two-channel orthogonal FIR filter bank. Haar filters...
In this study, a modification to ISO MPEG-1 and MPEG-2 digital video coding standards is proposed and preliminary results on its performance are reported. The proposed modification aims to improve the visual quality of MPEG-1 and MPEG-2 coding at medium-to-low bit-rate regimes by eliminating the blocking effect caused by the Discrete Cosine Transform. This goal is achieved without introducing a significant...
In this work, two new design techniques for matched (adaptive) orthogonal block transforms (BT) based partly on Vector Quantization (VQ) are presented. Both techniques start from reference vectors that are adapted to the characteristics of the signal to be coded. Then the corresponding orthogonal block transform is obtained in the first technique via signed permutations of the reference vector, while...
Multiple intra-mode prediction is one of the new features introduced in the emerging video standard, H.264/AVC. Its function is to further reduce spatial redundancies in an intracoded macroblock prior to conventional transform coding and entropy coding. However, the process is computationally expensive especially when Lagrangian cost evaluation is employed. In this paper, we propose a fast algorithm...
In this paper we propose novel strategies for reducing the practical limitations of the Singular Value Decomposition (SVD) for image compression. First, the computational cost is reduced by computing only a limited number of eigenvectors. Second, an online Adaptive Vector Quantization (AVQ) method is used to achieve a low bit rate. Simulation results show that the proposed algorithm is better than...
An algorithm for optimal selection of wavelet packet transforms for object-based coding is presented in this paper. The method exploits the object statistics at each GOP or scene period and estimate an optimal wavelet packet tree and an optimal quantizer for each object so that a) objects of importance (e.g., foreground) are transmitted with higher bit rate (quality) than the background objects, while...
A new scheme is proposed which uses the features of Discrete Cosine Transform (DCT) for the embedding of the watermark coefficients and uses a pseudo-random sequence for selection of the DCT coefficients to embed the watermark. These coefficients are different in different watermarked images so there is no chance of collusion of the watermarked images to detect the watermark illegally. The scheme...
Modification of the quantizer value based on a region's visual importance within a frame is a popular and widely-used procedure in perceptual video coding. The first contribution of this paper is an alternative modification scheme. Second, our previous work, where we use saliency maps in order to guide the macroblock (MB) mode decision during the ratedistortion optimization process, is extended. Modification...
Wireless video sensor networks (WVSN) are foreseen to be a key driver of the development of pervasive applications of every-day life. They trigger very challenging problems due to their constrained nature in terms of energy, bandwidth, processing and storage means. In order to be able to assess the performances of their proposals, WVSN's researchers community needs a transmission and evaluation tool...
In this paper, we propose a content adaptive transform (CAT) method for video coding. Firstly, CAT obtains the transform kernels in real-time instead of predefined fixed ones, and therefore it is content based transform. Secondly, the transform kernels is obtained by singular value decomposition (SVD) from a typical decoded block without transmitting them to the decoder. Thirdly, the optimality property...
In this paper, a novel partial encryption method for video encoding is proposed. For video compression based on block transforms, two zig-zag scan orders can be used which provide similar compression performance. The proposed method involves randomly selecting one of these two scan orders. In addition, the sign bit of the DC coefficients can be flipped randomly and when employed with the proposed...
Intra prediction coding is mainly to eliminate the correlation of the spatial domain. Firstly the article introduces the traditional intra prediction algorithm. And then according to the correlation between the most likely patterns and best mode, It draws a pattern matrix. By the advantage of this mode matrix for early termination, it can improve the efficiency of intra prediction 9%–15% in the condition...
In Mode-Dependent Directional Transform (MDDT), Karhunen¨CLo¨¨ve Transform (KLT) was employed to better compress the directional edges of intra prediction residues. The transform bases of MDDT were derived from the Singular Value Decomposition (SVD) of the intra prediction residues with the diversity of video characteristics. MDDT was mode dependent, but not video content dependent. It was expected...
In this study, a new adaptive post-filtering algorithm is proposed to remove observed blocking artifacts as a result of discrete cosine transform (DCT) based image and video compression standarts at low bit rates. With identification of blocking artifact strength, fuzzy filter is applied by adjusting filtering range and its parameters. Experimental results showed that, the proposed algorithm exhibits...
In video coding, motion compensation prediction residuals are typically compressed by applying two-dimensional transforms such as the two-dimensional discrete cosine transform (2D-DCT). Using direction-adaptive one-dimensional discrete cosine transforms (1D-DCTs) can provide significant additional bitrate savings. However, this requires optimization over all available transforms to minimize the overall...
This paper presents a fast intra mode decision algorithm using the sum of absolute transformed differences (SATD) in order to reduce the encoding time. Our algorithm consists of two main techniques: Early block-mode decision and candidate directional-mode selection. First, we use the early block-mode decision method, I4MB skip, to avoid unnecessary computation for I4MB. If all the 16 4x4sub-blocks...
A novel video coding scheme is presented with superior performance against packet losses and hence is suitable for wireless communication compared to standard approaches like scalable video coding. The scheme also offers a better multi-rate video solution by offering multiple options for receiving videos at each sub-rate. The approach is suitable for use on multiple channels as well as on a single...
This paper studies the rate-distortion (R-D) performance of entropy-constrained dead-zone plus uniform threshold scalar quantization (DZ+UTSQ) and nearly-uniform reconstruction quantization (NURQ) for generalized Gaussian distribution (GGD). We first derive the preliminary constraint of R-D optimized DZ+UTSQ/NURQ for GGD. Then for GGD source of actual DCT coefficients, the refined constraint and precise...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.