Recently, several methods that divide the original bitstream of an image/video progressive wavelet based source coders into multiple correlated substreams have been proposed. The principle behind transmitting independ...
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ISBN:
(纸本)9780819469946
Recently, several methods that divide the original bitstream of an image/video progressive wavelet based source coders into multiple correlated substreams have been proposed. The principle behind transmitting independent multiple substream is to generate multiple descriptions of the source such that the graceful degradation is achieved when transmitted over severe fading channels and lossy packet networks since some of the streams may be recovered. Noting that multiple substream can benefit from multiple independent channel paths, we naturally consider Multi-Input Multi-Output communication systems where we obtain multiple independent fading channels. Depending on several factors including: the number of antennas employed, the transmission energy, the Doppler shift (due to the motion between the transmitter antenna and receiver antennas), the total transmission rate and the distortion-rate (D-R) of the source-there exists an optimal number of balanced substreams and an optimal joint source-channel coding policy such that the expected distortion at the receiver is minimized. In this paper we derive an expected distortion function at the receiver based on all of. these parameters and provide a fast real-time numerical technique to find the optimal or near optimal number of balanced substreams to be transmitted. This expected distortion is based on our derivation of the probabilistic loss patterns of a balanced multiple substream progressive source coder.. The accuracy of the derived expected distortion estimator is confirmed by Monte-Carlo simulation employing Dent's modification of Jakes' model. By accurately estimating the optimal number of balanced substream's to be transmitted, a substantial gain in visual quality at low and intermediate signal-to-noise ratio (SNR) is obtained over severely fading channels.' At hi-h SNR, the single stream source coder's source efficiency makes it slightly better than the multiple substream source coder. Overall, using our analytic
This paper presents an error protection method for embedded wavelet codec by combining data hiding with error concealment. For the lowest frequency coefficients, a prolection scheine based data hiding is peifol-ined. ...
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ISBN:
(纸本)9781424410651
This paper presents an error protection method for embedded wavelet codec by combining data hiding with error concealment. For the lowest frequency coefficients, a prolection scheine based data hiding is peifol-ined. The lowest frequency coefficients, which are taken as the hidden data, are extracted from the compressed bilstream, and embedded back into the same bitstream. The restored hidden data is used to conceal errors. The coefficients that cannot be recovered in other high frequency coefficients reconstruction are predicted through linear interpolation based oil inter-subband correlation. Experimental results show that the proposed method achieves good and stable error performance with minimal additional redundancy.
An improved coding algorithm called spiht coding is introduced in detail, and the algorithm can control the quantity effectively, meet the needs of disposal instantly, and provide high performance and low complexity i...
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ISBN:
(纸本)9812700420
An improved coding algorithm called spiht coding is introduced in detail, and the algorithm can control the quantity effectively, meet the needs of disposal instantly, and provide high performance and low complexity in image compression. Experimental results show that the proposed algorithm is much efficient wavelet-based image compression algorithm.
With the fast evolution of Multimedia systems, Image compression algorithms are very much needed to achieve effective transmission and compact storage by removing the redundant information of the image data. Wavelet t...
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With the fast evolution of Multimedia systems, Image compression algorithms are very much needed to achieve effective transmission and compact storage by removing the redundant information of the image data. Wavelet transforms have received significant attention, recently, due to their suitability for a number of important signal and image compression applications and the lapped nature of this transform and the computational simplicity, which comes in the form of filter bank implementations. In this paper, the implementation of image compression algorithms based on discrete wavelet transform such as embedded zero tree wavelet (EZW) coder, set partitioning in hierarchical trees coder without lists (spiht — No List) and packetizable zero tree wavelet (PZW) coder in DSP processor is dealt in detail and their performance analysis is carried out in terms of different compression ratios, execution timing and for different packet losses. PSNR is used as the criteria for the measurement of reconstructed image quality.
In this paper, a subband image-coding scheme with adapted modulated wavelets is presented. Due to the fact that Gabor functions mimic well the simple cells of mammalian visual receptive field with optimum localization...
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In this paper, a subband image-coding scheme with adapted modulated wavelets is presented. Due to the fact that Gabor functions mimic well the simple cells of mammalian visual receptive field with optimum localization in the joint space-spatial frequency domain, we divide the image into subbands using discrete Gabor transform;decompose each subband into modulated wavelet (MW) coefficients with adapted modulating frequencies on a subband basis;and encode the complex-valued MW coefficients using the modified spiht in an embedded manner. Experimental results show that the proposed MW transform based subband coding is preferable to the wavelet transform based coding for images composed of textures with rapid variation in grays. (C) 2003 Elsevier B.V. All rights reserved.
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