Title :
Variable block-size double predictor DPCM (VBDP-DPCM) image transmission system over wireless fading channel
Author :
Wu, Jia-Chyi ; Chung, Neil H -C
Author_Institution :
Dept. of Commun. & Guidance Eng., Nat. Taiwan Ocean Univ., Keelung, Taiwan
Abstract :
A variable blocksize double predictor differential pulse code modulation (VBDP-DPCM) image coding algorithm is utilized for image transmission over Rayleigh fading channels. Quadtree segmentation algorithm is applied to divide a given digital image into segments of variable size, square blocks, in which the nonstationary statistical characteristics of the given image source can be better exploited. Each variable blocksize sub-image is then applied the double predictor DPCM (DP-DPCM) coding scheme to further reduce the quantization error and produce a better data compression ratio than that of a DPCM scheme. To improve the system performance for transmitting VBDP-DPCM encoded images over wireless fading channel, we have adopted the quadrature phase shift keying (QPSK) modulation as well as a channel coding algorithm in this study. The convolutional encoder and maximum-likelihood Viterbi hard decision decoder are applied to protect the transmitted source data and to reduce bit error rate (BER) in fading channel. Performance of this VBDP-DPCM image transmission system over Rayleigh fading channel is evaluated in this research.
Keywords :
AWGN channels; Rayleigh channels; Viterbi decoding; channel coding; convolutional codes; differential pulse code modulation; error correction codes; error statistics; image coding; image segmentation; maximum likelihood decoding; quadrature phase shift keying; quadtrees; quantisation (signal); AWGN channel; QPSK modulation; Rayleigh fading channel; additive white Gaussian noise channel; bit error rate; channel coding algorithm; channel error control code; convolutional encoder; data compression ratio; digital image; image transmission; maximum-likelihood Viterbi hard decision decoder; nonstationary statistical characteristic; quadrature phase shift keying modulation; quadtree segmentation algorithm; quantization error; variable blocksize double predictor differential pulse code modulation image coding algorithm; Bit error rate; Digital images; Fading; Image coding; Image communication; Image segmentation; Modulation coding; Pulse modulation; Quadrature phase shift keying; Quantization;
Conference_Titel :
Vehicular Technology Conference, 2003. VTC 2003-Fall. 2003 IEEE 58th
Print_ISBN :
0-7803-7954-3
DOI :
10.1109/VETECF.2003.1286222
