Video compression plays an important role in video signalprocessing, transmission and storage. Since the available bandwidth for transmission is very limited, Multimedia applications such as video conferencing, video...
详细信息
Video compression plays an important role in video signalprocessing, transmission and storage. Since the available bandwidth for transmission is very limited, Multimedia applications such as video conferencing, video on demand, video telephony and remote sensing are not possible without compression. A lot of video compression techniques have been developed and the video signal transmission has followed at data rates below 64kbps. wavelet transform based motion compensated video codec performs better compression in order to meet the rate and distortion constraint in video transmission for the available bandwidth than the block based techniques, which are followed in standard video transmissions such as H.261 and H.263. But the efficiency of those technique's depends on the way in which it estimates and compensates the object motions in the video sequence. wavelet based embedded image coder is quite attractive in modern multimedia applications. wavelet transform, bit plane coding and other techniques make embedded image coder practical and also provide efficient compression. In this paper, we have proposed a novel video coding using swarm intelligence in dual tree complex wavelet transform for video coding. The 3-D DDWT is an attractive video representation because it isolates motion along different directions in separate subbands. However, it is an over-complete transform with redundancy, which is going to be eliminated by choosing optimal subbands with the help of PSO. The proposed video codec does not require motion compensation and provides better performance than the 3D SPIHT (Embedded type)codec, both objectively and subjectively, and the coder allows full scalability in spatial, temporal and quality dimensions.
The quality of synthetic aperture radar (SAR) images generally suffers from speckle noise, which damages the radiometric resolution of SAR images. A new speckle reduction method is proposed by thresholding the speckle...
详细信息
ISBN:
(纸本)9781479910267
The quality of synthetic aperture radar (SAR) images generally suffers from speckle noise, which damages the radiometric resolution of SAR images. A new speckle reduction method is proposed by thresholding the speckled SAR image coefficients in the Shearlet transform domain. As a powerful multiscale image representation tool, Shearlet tranform enables better preservation of significant detail information in despeckled results. Compared with the wavelet transform, Shearlet transform is more suitable for image restoration applications where detail preservation is highly demanding. Experimental results on real X-band amplitude and intensity SAR images demonstrate the efficacy of the proposed method. A quantitative analysis is also given to show the superiority of the Shearlet-based thresholding method over the translation-invariant wavelet-based counterpart.
In this paper, we propose a new approach based on watermarking for fusing biometric modalities. The main idea of the proposed approach is to use the watermark both for security purpose and as an additional information...
详细信息
In this paper, we propose a new approach based on watermarking for fusing biometric modalities. The main idea of the proposed approach is to use the watermark both for security purpose and as an additional information related to the person, therefore increasing the personal data used for verification. The host image of the face is watermarked in the multi-resolution space by the palmprint using a watermarking technique based on wavelet packet decomposition. For the verification stage, the characterization of the watermarked face is provided by Gabor filters while classification is performed by SVMs. The experimental results show that this technique ensures a significant performance improvement in both identity verification and biometric security over the use of a single system.
Subdivision-based wavelet coding techniques yield state-of-the-art performance in scalable compression of semi-regular meshes. However, all these codecs make use of the L-2 distortion metric, which gives only a good a...
详细信息
Subdivision-based wavelet coding techniques yield state-of-the-art performance in scalable compression of semi-regular meshes. However, all these codecs make use of the L-2 distortion metric, which gives only a good approximation of the global error produced by lossy coding of the wavelet coefficients. The L-infinite metric has been proven to be a suitable metric for applications where controlling the local, maximum error on each vertex is of critical importance. In this context, an upper bound formulation for the L-infinite distortion for a wavelet-based coding scheme operating on semi-regular meshes is derived. In addition, we propose a rate-distortion optimization algorithm that minimizes the rate for any target L-infinite distortion. It is shown that our L-infinite coding system outperforms the state-of-the-art and that an L-2 driven coding approach for semi-regular meshes loses ground to its L-infinite driven version when the goal is to have a tight control on the local reconstruction error.
A perceptual image coder for the compression of monochrome images is presented here, in which the coding structure is coupled with a vision model to produce coded images with an improved visual quality at low bit-rate...
详细信息
ISBN:
(纸本)9780769530505;0769530508
A perceptual image coder for the compression of monochrome images is presented here, in which the coding structure is coupled with a vision model to produce coded images with an improved visual quality at low bit-rates. The coder is an improvement on the current image compression standard, JPEG2000. The proposed coding structure incorporates the human vision model in all stages of compression, and gives very good results compared to the existing wavelet based JPEG scheme. Though the mathematical model used are not new, the simple structure of it which can be easily incorporated into the coding structure of the JPEG2000, incorporates the visual processing stages in a very systematic manner in the same way as the visual neurons process the signal. The results presented in this paper reveal that the proposed structure gives very good perceptual quality compared to the existing scheme especially as we go for lower bit rates. One of the major advantages of the proposed scheme is that it can be easily extended to a structure in which the rate control optimization can be incorporated, as in the JPEG2000.
This paper presents a spread-spectrum watermarking algorithm for embedding text watermark in to digital images in discrete wavelet transform (DWT) domain. The algorithm is applied for embedding text file represented i...
详细信息
ISBN:
(纸本)9781479984992
This paper presents a spread-spectrum watermarking algorithm for embedding text watermark in to digital images in discrete wavelet transform (DWT) domain. The algorithm is applied for embedding text file represented in binary arrays using ASCII code into host digital radiological image for potential telemedicine applications. In order to enhance the robustness of text watermarks like patient identity code, BCH (Bose, Ray-Chaudhuri, Hocquenghem) error correcting code (ECC) is applied to the ASCII representation of the text watermark before embedding. Performance of the algorithm is analysed by varying the gain factor, subband decomposition levels, and length of watermark. Robustness of the scheme is tested against various attacks like compression, filtering, noise, sharpening, scaling and histogram equalization. Simulation results show that the proposed method achieves imperceptible watermarking for string watermarks. It is also observed that the use of BCH code improves the performance by reducing bit error rate (BER) performance.
The standard format for video acquisition, transmission and presentation uses an interlaced scanning technique. On the other hand for digital video services, the progressive format is more desirable in many situations...
详细信息
The standard format for video acquisition, transmission and presentation uses an interlaced scanning technique. On the other hand for digital video services, the progressive format is more desirable in many situations, and different resolutions of the signal are required. The interlaced scan is based on a tight concatenation of vertical and temporal sampling effects. This paper introduces the technique of motion-compensated vertical filters within pairs of fields to solve the problem of sampling rate conversion between interlaced and progressive raster. It is shown that the motion-compensated vertical filter is a polyphase realization of a factor-2 up- or downsampling filterbank, with polyphase shift controlled by motion parameters. Possible applications are down- and up-conversion between progressive and interlaced formats, and multiresolution representation of video data within a spatio-temporal subband or wavelet framework.
The ancient documents have a major importance in the history of every people and every nation. These documents involve important information that many people need. As a consequence, it is necessary to preserve these d...
详细信息
The ancient documents have a major importance in the history of every people and every nation. These documents involve important information that many people need. As a consequence, it is necessary to preserve these documents in order to build a numerical library in the service of the public. Therefore, the necessity of digitizing these documents permits the simultaneous access to the same documents and provides the possibility of the reproduction of these documents existing most of the time in just one example. This task is considered as an important step in the research domain. In fact, many researches have been invested for the processing, compression, segmentation and indexation of these documents. Nevertheless, with a numerical form, there is a threat of hacking, stocking, copying, modifying and finally diffusing these documents in an illegal way without losing their quality. As a consequence, we face the problem of losing the intellectual property because of the lack of methods that concern the protection of data. In order to prevent these frauds, watermarking represents a promising method to protect these images. In this context, our work makes part of protecting ancient documents essentially. In this paper, we have proposed the method of watermarking ancient documents. This method is based on the wavelet Packet Transform (WPT) and it provides a good robustness which can face different attacks like signalprocessing (noise, filter and compression) and noticeable signature invisibility.
This paper proposes a data pruning-based compression scheme to improve the rate-distortion relation of compressed images and video sequences. The original frames are pruned to a smaller size before compression. After ...
详细信息
This paper proposes a data pruning-based compression scheme to improve the rate-distortion relation of compressed images and video sequences. The original frames are pruned to a smaller size before compression. After decoding, they are interpolated to their original size by an edge-directed interpolation. The data pruning is optimized to obtain the minimal distortion in the interpolation phase. Furthermore, a novel high order interpolation is proposed to adapt the interpolation to many edge directions. This high order filtering uses extra surrounding pixels and achieves more robust edge-directed image interpolation. Simulation results are shown for both image interpolation and coding applications.
暂无评论