Improved sub-block encoder of irregular LDPC code for image transmission

Author(s):  
Tanaporn Payommai ◽  
Werapon Chiracharit ◽  
Kosin Chamnongthai
Keyword(s):  
2012 ◽  
Author(s):  
Ierwan Ab. Karim ◽  
Abdul Karem Hussein Mohammed Almawgani ◽  
Mohd Fadzli Mohd Salleh

Dalam kertas ini prestasi kod ketumpatan–rendah kesetaratan–semak (LDPC) dan kod Reed–Solomon (RS) telah dianalisis dengan menggunakan sistem penghantaran imej tanpa wayar. Sistem ini menggunakan salur penambahan Gaussian hinggar putih (AWGN). Dalam kerja ini, imej kelabu telah telah digunakan sebagai punca kemasukan daya. Kualiti imej kelabu yang dibina semula selepas saluran penyahkodan adalah diukur dengan menggunakan puncak nisbah isyarat–hinggar (PSNR) dengan membandingkan imej yang dibina semula dengan kemasukan imej asal. Keputusan penyelakuan menunjukkan prestasi sistem penghantaran imej dengan menggunakan kod LDPC sentiasa mengatasi prestasi sistem yang menggunakan kod RS dalam salur AWGN. Kualiti keluaran imej kelabu adalah dianggap bagus sekiranya nilai PSNR melebihi 30 dB. Kata kunci: Sistem penghantaran imej tanpa wayar; kod LDPC; kod Reed Solomon; salur AGWN In this paper the performance of Low–Density Parity–Check (LDPC) and Reed–Solomon (RS) codes are analyzed using a wireless image transmission system. The system utilizes the Additive White Gaussian Noise (AWGN) channel. In this work, a grayscale image is used as the input data source. The quality of the reconstructed grayscale image after the channel decoder is measured using the Peak Signal to Noise Ratio (PSNR) by comparing the reconstructed image with the input grayscale image. Simulation results show that the performance of image transmission system using LDPC code is always outperformed the system with RS code in AWGN channel. The quality of output grayscale image is considered good if the value of the PSNR is above 30 dB. Key words: Wiresless image transmission system; LDPC code; Reed Solomon code; AWGN channel


2014 ◽  
Vol 602-605 ◽  
pp. 3223-3227
Author(s):  
Hua Xu

Low encoding delay and complexity is very important for image transmission. This paper proposes a novel image transmission scheme with low encoding complexity. The proposed scheme is based on quasi-cyclic low density parity check (QC-LDPC) codes with a simple recursive encoding form (SREF QC-LDPC code) which results in low encoding complexity and delay. Constructing the SREF QC-LDPC codes in this scheme composes of two main steps, construction of the base matrix and the exponent matrix. We combine the differential evolution and protograph extrinsic information transfer (PEXIT) method to optimize the base matrix of QC-LDPC code. Consequently, the exponent matrix and the parity check matrix are constructed. Simulation results show that the proposed scheme based on SREF QC-LDPC code can provide a good tradeoff between the performance and complexity.


Author(s):  
Vinod K. Berry ◽  
Xiao Zhang

In recent years it became apparent that we needed to improve productivity and efficiency in the Microscopy Laboratories in GE Plastics. It was realized that digital image acquisition, archiving, processing, analysis, and transmission over a network would be the best way to achieve this goal. Also, the capabilities of quantitative image analysis, image transmission etc. available with this approach would help us to increase our efficiency. Although the advantages of digital image acquisition, processing, archiving, etc. have been described and are being practiced in many SEM, laboratories, they have not been generally applied in microscopy laboratories (TEM, Optical, SEM and others) and impact on increased productivity has not been yet exploited as well.In order to attain our objective we have acquired a SEMICAPS imaging workstation for each of the GE Plastic sites in the United States. We have integrated the workstation with the microscopes and their peripherals as shown in Figure 1.


1992 ◽  
Vol 139 (5) ◽  
pp. 495 ◽  
Author(s):  
Q. Mongatti ◽  
L. Alparone ◽  
G. Benelli ◽  
S. Baronti ◽  
F. Lotti ◽  
...  

2009 ◽  
Vol E92-B (5) ◽  
pp. 1504-1515 ◽  
Author(s):  
Naoto OKUBO ◽  
Nobuhiko MIKI ◽  
Yoshihisa KISHIYAMA ◽  
Kenichi HIGUCHI ◽  
Mamoru SAWAHASHI

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