This paper proposes an image watermarking algorithm that is robust to compression methods and noise addition. In the proposed method the wavelet transform of images is taken and watermarking is carried out in the wave...
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ISBN:
(纸本)0780383184
This paper proposes an image watermarking algorithm that is robust to compression methods and noise addition. In the proposed method the wavelet transform of images is taken and watermarking is carried out in the wavelet domain. In order to accomplish low visibility of the watermark within the image and enable robustness against attacks, watermarking of block averages is utilized. Experimental results show that the proposed method is considerably more robust against corrupting effects such as JPEG compression, addition of noise, cropping and scaling.
Digital images are claiming an increasingly larger portion of the information world. In this study, wavelet transform is chosen for image compression. image is decomposed into subbands of averages and details with wav...
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ISBN:
(纸本)0780383184
Digital images are claiming an increasingly larger portion of the information world. In this study, wavelet transform is chosen for image compression. image is decomposed into subbands of averages and details with wavelet transform. Obtained detail subbands have small valued coefficents that also constitute a small percentage of image energy. If these small valued coefficents are quantized to zero with a chosen threshold, there will be no great loss in the image. This feature provided by wavelet transform is a basis for set partitioning in hierarchical trees algorithm. With this algorithm discrete wavelet transform coefficents are organized in spatial orientation trees. The reason to have formed these trees is gathering all pixels that are highly correlated with each other. With this kind of set structure, the similarity among the coefficents in a set from one level to the next is increased. The main aim in this algorithm is to code the trees with highly correlated, zero valued coefficients with a single code word. With these features in the nature of wavelet transform and set partitioning in hierarchical trees algorithm, it is intended to get high compression ratios in images.
In this paper, we present techniques based on multiple wavelet-tree coding for robust image transmission. The algorithm of set partitioning in hierarchical trees (SPIHT) is a state-of-the-art technique for image compr...
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ISBN:
(纸本)0819455539
In this paper, we present techniques based on multiple wavelet-tree coding for robust image transmission. The algorithm of set partitioning in hierarchical trees (SPIHT) is a state-of-the-art technique for image compression. This variable length coding (VLC) technique, however, is extremely sensitive to channel errors. To improve the error resilience capability and in the meantime to keep the high source coding efficiency through VLC, we propose to encode each wavelet tree or a group of wavelet trees using SPIHT algorithm independently. Instead of encoding the entire image as one bitstream, multiple bitstreams are generated. Therefore, error propagation is limited within individual bitstream. Two methods based on subsampling and human visual sensitivity are proposed to group the wavelet trees. The multiple bitstreams are further protected by the rate compatible puncture convolutional (RCPC) codes. Unequal error protection are provided for both different bitstreams and different bit segments inside each bitstream. We also investigate the improvement of error resilience through error resilient entropy coding (EREC) and wavelet tree coding when channels are slightly corruptive. A simple post-processing technique is also proposed to alleviate the effect of residual errors. We demonstrate through simulations that systems with these techniques can achieve much better performance than systems transmitting a single bitstream in noisy environments.
image compression techniques are routinely applied to conserve storage space and minimize bandwidth utilization in various video and communication applications. wavelet transform is an efficient approach to reduce spa...
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ISBN:
(纸本)0769521088
image compression techniques are routinely applied to conserve storage space and minimize bandwidth utilization in various video and communication applications. wavelet transform is an efficient approach to reduce spatial redundancies without the annoying blocking artifacts at low bit rates. The underlying signalprocessing used in wavelet transform is the convolution between the decimated input signal and the wavelet filters. Since imagesignals are not continuous at the boundaries, problems of coefficient expansion and boundary distortion are faced in the implementation of the filtering on the finite length signal. Circular convolution instead of linear convolution can eliminate coefficient expansion but introduce boundary artifacts, especially when more levels of decompositions are involved to obtain scalable images. Symmetric-extended wavelet transform (SWT) introduced in this paper can greatly reduce boundary artifacts with improved performances in scalable image compression in comparison with the periodic-extended wavelet transform and the JPEG compression.
A new algorithm is developed to merge a high-resolution panchromatic image and a low-rcsohition multi-spcctral image based on the combination of multi-resolution wavelet decomposition and the IHS *** high-resolution p...
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ISBN:
(纸本)0780385624
A new algorithm is developed to merge a high-resolution panchromatic image and a low-rcsohition multi-spcctral image based on the combination of multi-resolution wavelet decomposition and the IHS *** high-resolution panchromatic image is firstly ciecornposed to the wavelet planes,then the region is divided by edge information from the wavelet planes and the intensity component from multi-spectral image is merged by fusion operator in different *** proposed method is compared with the IHS and the MWT *** experimental results show that the proposed method can achieve better fusion performance in combining and preserving spectral-spatial information.
In this paper, we propose a wavelet-based fast motion estimation algorithm for video sequence encoding with a low bit-rate. By using one of the properties of the wavelet transform, multi-resolution analysis (MRA), and...
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ISBN:
(纸本)0819454966
In this paper, we propose a wavelet-based fast motion estimation algorithm for video sequence encoding with a low bit-rate. By using one of the properties of the wavelet transform, multi-resolution analysis (MRA), and the spatial interpolation of an image, we can simultaneously reduce the prediction error and the computational complexity inherent in video sequence encoding. In addition, by defining a significant block(SB) based on the differential information of the wavelet coefficients between successive frames, the proposed algorithm enables us to make up for the increase in the number of motion vectors when the MRME algorithm is used. As a result, we are not only able to improve the peak signal-to-noise ratio (PSNR), but also reduce the computational complexity by up to 67%.
wavelet transform has been widely used in many signalprocessingapplications. Advanced researches have intensively investigated the characteristics of wavelet filters, adaptive wavelet decomposition structure for cod...
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Lossless video coding techniques are needed for applications that cannot tolerate any loss of visual information. In this paper, we propose a new wavelet-based lossless video coding scheme that switches between two op...
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ISBN:
(纸本)7121002159
Lossless video coding techniques are needed for applications that cannot tolerate any loss of visual information. In this paper, we propose a new wavelet-based lossless video coding scheme that switches between two operations based on the different amount of motion activities between two consecutive frames. For low motion frames, differential coding of wavelet coefficients without motion compensation in spatial domain is applied. For frames with more moving areas, motion compensation in spatial domain is first performed, and wavelet coefficients of residuals are then entropy coded. Experiments show that the proposed scheme significantly improves the compression ratio over JPEG-LS.
The directionality and phase information provided by non-redundant complex wavelet transforms (NCWTs) provide significant potential benefits for image/video processing and compression applications. However, because ex...
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The directionality and phase information provided by non-redundant complex wavelet transforms (NCWTs) provide significant potential benefits for image/video processing and compression applications. However, because existing NCWTs are created by downsampling filtered wavelet coefficients, the finest scale of these transforms has resolution 4× lower than the real input signal. In this paper, we propose a linear-phase, semi-orthogonal, directional NCWT design using a novel triband filter bank. At the finest scale, the resulting transform has resolution 3× lower than the real input signal. We provide a design example to demonstrate three important properties for image/video processingapplications: directionality, magnitude coherency, and phase coherency.
Introduction of digital communication network such as Integrated Services Digital Networks(ISDN) and digital storage media have rapidly developed. Due to a large amount of image data., compression is the key technique...
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ISBN:
(纸本)0819451673
Introduction of digital communication network such as Integrated Services Digital Networks(ISDN) and digital storage media have rapidly developed. Due to a large amount of image data., compression is the key techniques in still image and video using digital signalprocessing for transmitting and storing. Digital image compression provides solutions for various imageapplications that represent digital image requiring a large amount of data. In this paper, the proposed DWT(Discrete wavelet Transform) filter bank is consisted of simple architecture, but it is efficiently designed that a user obtains a wanted compression rate as only input parameter. If it is implemented by FPGA chip, the designed encoder operates in 12MHz.
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