23,284 research outputs found
Optimal Progressive Image Transmission Over Rayleigh Fading Channels
A fixed-packet optimal joint source channel coding scheme for transmission of progressive images over Rayleigh channels is proposed. A first order Markov model is used in rate allocation problem to concern channel temporal variations during image transmission. Also, introducing a modification on the used progressive coding scheme, the requirement for the immediate decoding termination upon the observation of an erroneous packet is relatively relaxed. A rate allocation mechanism for this modified version of progressive codes is also proposed
Minimum Distortion Variance Concatenated Block Codes for Embedded Source Transmission
Some state-of-art multimedia source encoders produce embedded source bit
streams that upon the reliable reception of only a fraction of the total bit
stream, the decoder is able reconstruct the source up to a basic quality.
Reliable reception of later source bits gradually improve the reconstruction
quality. Examples include scalable extensions of H.264/AVC and progressive
image coders such as JPEG2000. To provide an efficient protection for embedded
source bit streams, a concatenated block coding scheme using a minimum mean
distortion criterion was considered in the past. Although, the original design
was shown to achieve better mean distortion characteristics than previous
studies, the proposed coding structure was leading to dramatic quality
fluctuations. In this paper, a modification of the original design is first
presented and then the second order statistics of the distortion is taken into
account in the optimization. More specifically, an extension scheme is proposed
using a minimum distortion variance optimization criterion. This robust system
design is tested for an image transmission scenario. Numerical results show
that the proposed extension achieves significantly lower variance than the
original design, while showing similar mean distortion performance using both
convolutional codes and low density parity check codes.Comment: 6 pages, 4 figures, In Proc. of International Conference on
Computing, Networking and Communications, ICNC 2014, Hawaii, US
Scalable video/image transmission using rate compatible PUM turbo codes
The robust delivery of video over emerging wireless networks poses many challenges due to the heterogeneity of access networks, the variations in streaming devices, and the expected variations in network conditions caused by interference and coexistence. The proposed approach exploits the joint optimization of a wavelet-based scalable video/image coding framework and a forward error correction method based on PUM turbo codes. The scheme minimizes the reconstructed image/video distortion at the decoder subject to a constraint on the overall transmission bitrate budget. The minimization is achieved by exploiting the rate optimization technique and the statistics of the transmission channel
Implementation issues in source coding
An edge preserving image coding scheme which can be operated in both a lossy and a lossless manner was developed. The technique is an extension of the lossless encoding algorithm developed for the Mars observer spectral data. It can also be viewed as a modification of the DPCM algorithm. A packet video simulator was also developed from an existing modified packet network simulator. The coding scheme for this system is a modification of the mixture block coding (MBC) scheme described in the last report. Coding algorithms for packet video were also investigated
A robust coding scheme for packet video
A layered packet video coding algorithm based on a progressive transmission scheme is presented. The algorithm provides good compression and can handle significant packet loss with graceful degradation in the reconstruction sequence. Simulation results for various conditions are presented
Study and simulation of low rate video coding schemes
The semiannual report is included. Topics covered include communication, information science, data compression, remote sensing, color mapped images, robust coding scheme for packet video, recursively indexed differential pulse code modulation, image compression technique for use on token ring networks, and joint source/channel coder design
Progressive transmission of medical images
A novel adaptive source-channel coding scheme for progressive transmission of medical images with a feedback system is therefore proposed in this dissertation. The overall design includes Discrete Wavelet Transform (DWT), Embedded Zerotree Wavelet (EZW) coding, Joint Source-Channel Coding (JSCC), prioritization of region of interest (RoI), variability of parity length based on feedback, and the corresponding hardware design utilising Simulink. The JSCC can achieve an efficient transmission by incorporating unequal error projection (UEP) and rate allocation. An algorithm is also developed to estimate the number of erroneous data in the receiver. The algorithm detects the address in which the number of symbols for each subblock is indicated, and reassigns an estimated correct data according to a decision making criterion, if error data is detected. The proposed system has been designed based on Simulink which can be used to generate netlist for portable devices. A new compression method called Compressive Sensing (CS) is also revisited in this work. CS exhibits many advantages in comparison with EZW based on our experimental results. DICOM JPEG2000 is an efficient coding standard for lossy or lossless multi-component image coding. However, it does not provide any mechanism for automatic RoI definition, and is more complex compared to our proposed scheme. The proposed system significantly reduces the transmission time, lowers computation cost, and maintains an error-free state in the RoI with regards to the above provided features. A MATLAB-based TCP/IP connection is established to demonstrate the efficacy of the proposed interactive and adaptive progressive transmission system. The proposed system is simulated for both binary and symmetric channel (BSC) and Rayleigh channel. The experimental results confirm the effectiveness of the design.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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