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In this paper, a rate-distortion optimized variable block transform coding scheme is proposed based on a hierarchical structured transform for macroblock (MB) coding with a set of the order-4 and -8 integer cosine transform (ICT) kernels of H.264/AVC as well as a new order-16 ICT kernel. The set of order-4, -8 and -16 ICT kernels are applied for inter-predictive coding in square (4 × 4, 8 × 8 or 16...
An image compressing technique for High Dynamic Range (HDR) image sensors is introduced. Compression is performed in two steps: Pixel value coding optimization followed by DCT-based (Discrete Cosine Transform) compression. A floating point coding technique is first used with a common exponent shared between pixels of the same block, and then a DCT is applied to each group of pixels. This new concept,...
In order to further improve the performance of rate control in H.264, a pixel-level rate control algorithm for the optimal prediction residual is proposed. Firstly, this proposed algorithm determines whether discrete cosine transform (DCT) should be applied to the macro block according to the simple rate distortion optimization (RDO) mode. Then quantization parameter (QP) is determined through a new...
In this paper a multiple frequency domain steganography is proposed; it uses DWT (discrete wavelets transform) with DCT (discrete cosine transform) techniques, which are applied sequentially on the cover image. Embedding the secret message is done in the high frequency coefficients to provide a high imperceptibility; as it is the most important property of any steganography system. For secret message...
A discrete cosine transform (DCT) can be easily implemented in software and hardware for the JPEG and MPEG formats. Recently, some integer DCTs (IntDCTs) for lossless-to-lossy image coding have been proposed, but they do not satisfy enough compatibility with JPEG standard. This paper proposes a realization of lossless-to-lossy image coding which has higher compatibility with it than the conventional...
This paper proposes a new approach to combined spatial (Intra) prediction and adaptive transform coding in block-based video and image compression. Context-adaptive spatial prediction from available, previously decoded boundaries of the block, is followed by optimal transform coding of the prediction residual. The derivation of both the prediction and the adaptive transform for the prediction error,...
Intra coding is used for reducing the spatial redundancy in video coding. H.264/AVC supports several MB (macroblock) predictions for intra coding. These intra predictions have also several directional prediction modes, which significantly improve intra coding efficiency, but increase the encoding complexity. In this paper, a fast intra prediction mode decision algorithm is proposed for the H.264/AVC...
In this paper, a motion compensated temporal filtering (MCTF) framework based on the discrete cosine transform (DCT) is proposed and named MCDCT-TF. It is able to employ filters of any length with particular emphasis on 5/3 DCT and 7/4 DCT. The proposed MCDCT-TF and the two-dimensional (2-D) DCT decimation technique are incorporated into H.264/AVC to provide spatio-temporal scalability. Compared with...
This paper presents a simple model of complex real time MPEG-4 video encoding and decoding using simple techniques in VHDL and MATLAB to provide reasonable compression while using only less power and resources on FPGA. This implementation works on low power and less number of clock cycles. The basic video codec module consists of a video encoder and a decoder. The encoder module consists of blocks...
The paper analyzes the characteristic features of hyper-spectral image and presents a compression of hyper-spectral images based on quadtree partitioning. Quadtree partition is used to get the mean image of the whole image and the significant correlation of image can be decorrelated by subtract the mean image from original image. The difference image is compressed by DCT and encoded with arithmetic...
In this paper we describe a practical implementation of a distributed video codec deployed on a real visual sensor platform, viz. the MicaZ/Cyclops platform. The codec supports two encoding schemes, one employs Discrete Cosine Transform (DCT) and the other operates on raw pixels. DCT scheme is more costly in terms of computational power consumption, on the other hand it leads to more compression and...
This paper presents a new transform framework, intra-predictive transforms, for block-based image coding. The proposed framework unifies cross-block prediction and transforms within a block. Thus, it can exploit both the intra- and inter- block correlations. The intra-prediction in H.264 can be viewed as a special case of intra-predictive transforms. The new framework provides more flexibility to...
To reduce the bandwidth requirement and the size of frame memory for video decoding, embedding a compressor/decompressor on the chip is a well-known solution. Video compression has been developed for a long time and numbers of algorithm have been proposed. Those algorithms show us that enhancing the complexity can reach better performance. However, algorithm with higher complexity is more difficult...
Conventional block based motion estimators assume constant inter-frame object brightness. Pixel discrepancy is resulted primarily from motion factor without considering the influence of brightness changes. In this paper, we propose a simple and efficient windowing technique using the Hamming window and integrate it to our previously proposed algorithm. The algorithm is based on retinex approach using...
A printed photograph is difficult to reuse because the digital pixels that generated it are no longer available. This paper describes approximating the original digital pixels by combining a scan of the printed photograph with small amounts of digital auxiliary information kept with the print, using an encoding such as a dense barcode. The auxiliary information enables accurate registration and color-reproduction,...
The VQM (Video Quality Measurement) scheme is a methodology that measures the difference of quality between the distorted video signal and the reference video signal. In this paper, we propose a novel video quality measurement method that extracts features in DCT (Discrete Cosine Transform) domain of H.263 SDTV. Main idea of the proposed method is to utilize the texture pattern and edge oriented information...
H.264/AVC is the compression technology to effectively transmit the video data which have an enormous amount of information and it have various methods such as the motion estimation & motion compensation, DCT(discrete cosine transform), entropy coding, and deblocking filter, for the seven variable blocks. The compression efficiency is increased due to these methods, however, the encoding time...
This paper study and analysis the video coding algorithms, which are standard for low bit rate communication. The image source format and picture structure and type are introduced at first. Then the coding algorithms employed in H.263+ and H.264 are introduce, which are a hybrid DPCM/transform algorithm, prediction ,DCT, motion estimation, variable run-length coding,. Furthermore, the generally used...
Digital image/video coding standards such as JPEG, H.264 are becoming more and more important for multimedia applications. Due to the huge amount of computations, there are significant efforts to speed up the encoding process. This paper proposes a Laplacian based statistical model to predict zero-quantized DCT coefficients in JPEG and to reduce the computations of encoding process. Compared with...
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