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H.264 adopts variable length coding and interprediction techniques, so compressed image is very sensitive to channel error. Meanwhile errors will influence subsequent frames, easily leading to the distortion of rebuilding images. To enhance the quality of reconstructed images, this text proposes a weighted outer boundary matching algorithms based on multiple reference frames, which exploits the characteristic...
Markov Random Field (MRF) has been successfully used to formulate the energy minimization problems in computer vision. However, a multi-label MRF model such as the conventional true motion estimation approach requires a significant amount of computation due to its large search space. Besides, we observe that decoding information obtained from H.264/AVC could be applied to reduce the computational...
This paper presents an image authentication scheme to verify the integrity of images. The method protects a group of n images mutually by applying a threshold mechanism to manipulate the recovery data. The authentication code and the recovery data are embedded using a modified reversible contrast mapping watermarking scheme. The proposed method not only can detect and locate the tampering activities...
Total variation regularization can be used to decompose any natural image into a structure image (edges and smooth areas) and a texture image (texture only). Although structure images can be highly compressed by conventional JPEG methods, texture images require a lot of bits to represent their feature details. Texture images are composed from several repeated patterns, each of which can be synthesized...
The purpose of this paper is to describe the difference between edge detection based on software and the full use of hardware resources within the FPGA. According to the video signal theory and edge detection algorithm, the author designs the IP core of video image edge detection and builds the video image edge detection system on the EDK. The hardware circuit of the algorithm is achieved on ISE9...
Digital watermarking has been a practical and interesting research topic in the last decade. Recently, a newly developed branch called reversible data hiding has emerged. It has attracted more and more attention in both researches and applications. With the definition of reversible data hiding, secret message can be hidden by schemes offered by algorithm designers. On the other hand, at the data extraction...
The decoding error rate of watermarking codes on the binary symmetric channel with bit-error probability f is an important performance index of watermarking system. The current information-theoretic models are mainly for gray scale images. This paper provides a theoretical model to analyze the watermarking code for dispersed ordered dithered halftone images using Hilbert curve decomposition. The analytical...
In contrast with the traditional video compression system, Distributed Video Coding (DVC) architecture dramatically shifts the complexity from the encoder to the decoder. This low-cost encoding concept can be exploited in the emerging applications, e.g. wireless sensor networks. In order to increase the compression efficiency, improvement of side information generation and refinements of Correlation...
Deblocking filter of H.264 is identified as an important technology for improving the subjective quality of video. However, it is difficult to apply to low-cost embedded terminals due to its high computational complexity. By analyzing the statistical correlations of boundary strength and true-edge detection checks among adjacent blocks and pixels, this paper proposes an enhanced method of deblocking...
Motion estimation as well as the corresponding motion compensation is a core part of modern video coding standards, which highly improves the compression efficiency. On the other hand, motion information takes considerable portion of compressed bit stream, especially in low bit rate situation. In this paper, an efficient motion vector prediction algorithm is proposed to minimize the bits used for...
The existing distortion correction methods are not fully suitable the multi-distortion image of Data Matrix symbol directly marked on cylinder surface, so an ellipse-arc grid method is proposed to correct this kind of distortion image. Firstly, two ellipse-arc boundaries and two line boundaries are detected based on the symbol contour point set, Secondly, two groups of ellipse-arc and line are interpolated...
H.264/AVC intra encoder uses nine prediction modes in 4×4 and 8×8 block unit to reduce the spatial redundancies. Too many intra modes not only increase the encoder complexity but also increase the number of overhead bits. In order to reduce the number of overhead bits and computational cost, an intra mode bit rate reduction (BRR) method is proposed in this paper. In the proposed method, the numbers...
Most current Wyner-Ziv (WZ) video codecs are based on channel coding and work in a frame by frame manner. That is, bit planes from pixels in a whole frame or coefficient band are channel coded. This structure of WZ video coding has the drawback that it can not adapt well to the spatially variable characteristics of a video frame, and hence leads to performance loss. To overcome the drawback, we propose,...
This paper presents a study on joint coding of video plus depth utilizing the correlation between video and depth. The Rate Distortion Optimization (RDO) technique has been employed in H.264 for intra prediction mode selection to achieve better coding efficiency. The proposed method considers the color video and depth video to compress jointly, which is based on the RDO mode decision algorithm and...
High resolution VC-1 (Video Codec-1) contents are becoming omnipresent over internet and local storage devices thus pushing the need of supporting high definition VC-1 video decoding in current generation handheld devices. Texas Instrument's (TI) OMAP3430 (Open Multimedia Applications Platform) is a multimedia processor which is highly used in portable devices. This paper describes the efficient implementation...
In the new Wyner-Ziv (WZ) video coding paradigm, a virtual correlation channel is assumed between the quantized source and the side information (SI) at the decoder, and channel coding is generally applied to achieve compression. In this paper, we address errors caused by the virtual correlation channel and propose an error concealment approach for pixel-based WZ video coding. In the approach, errors...
We are developing the detector system of C-SPECT-I, the first generation system of a dedicated Cardiac SPECT platform. For cost-effectiveness, we use medium size single-anode PMTs with NaI(Tl) detector modules to form the body-contouring shape of the C-SPECT detector arc. We have designed and evaluated a test detector module that includes two pixelated NaI(Tl) detector blocks in a common hermetic...
This work will discuss the design of a high-linearity, low dispersion injection circuit to be used for pixel-level calibration of detector readout electronics. The circuit allows for precise analog test of the pixel cell units already at the chip level, when no sensor is connected. Moreover, it provides a simple means for calibration of readout electronics once the detector has been connected to the...
The transmission of block-coded images over wireless channels results in lost blocks. In this paper, we propose a new error concealment method for covering up the high packet losses of an original image after its transmission through an error-prone channel. In this scheme, Discrete Wavelet Transform (DWT) is applied to each block of the original image in order to produce a lower resolution copy of...
Presently, distributed video coding (DVC) arouse high research interests due to the distinct contribution to the low-complexity encoding. In this paper, we propose a hash-based DVC, where the hash bits are compressed by a rate-adaptive low density parity coding accumulate (LDPCA) and sent to aid the decoder in motion estimation. The hash bit-rate is ideally near to its conditional entropy, so we name...
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