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Error-Protection Techniques of SPIHT-Coded Images in Packet Loss Network. 指導教授:楊士萱 報告者:鄭博峰 11 月 12 日. Error Protection techniques. Error resilience: Robustness. Needing to modify encoder. Needing add additional information. Channel coding: Correcting the errors.
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Error-Protection Techniques of SPIHT-Coded Images in Packet Loss Network 指導教授:楊士萱 報告者:鄭博峰 11月12日
Error Protection techniques • Error resilience: Robustness. Needing to modify encoder. Needing add additional information. • Channel coding: Correcting the errors. Adding correct codes. • Error Concealment: Estimating the data (loss or damage). Using correct data.
Outline • Wavelet Transform and SPIHT Coding • Error resilience: 1. Trees’ Partition and Packetization. 2. Multi-description in SPIHT • Error Concealment • Simulation • Conclusion
Flowchart Error resilience Source coder Wavelet coder SPIHT Image Channel Error concealment Wavelet Decoder SPIHT Decoder Image
Outline • Wavelet Transform and SPIHT Coding • Error resilience: 1. Trees’ Partition and Packetization. 2. Multi-description in SPIHT • Error Concealment • Simulation • Future work
Wavelet Transform • Gathering Energy in lowest subband. • Reconstructing original image. DWT DWT DWT DWT DWT DWT
Subband Coefficient Correlation CBrother,Parent >CBrother(up,left)>Cparent(H,D)>Ccousin(H,D)>Caunt(H,D)
SPIHT 1. * and highest subband have no son. 2. Others have 4 sons.
Outline • Wavelet Transform and SPIHT Coding • Error resilience: 1. Trees’ Partition and Packetization. 2. Multi-description in SPIHT • Error Concealment • Simulation • Future work
Trees’ Partition and Packetization • Partition into trees by direction. • 2. Packing with clan.
Multi-description in SPIHT • After Wavelet transforming , almost energy will gather in low frequency. • Using MDC to overcome this problem. • Copying lowest coefficients. • Encoding sub-lowest subband’s sign. • Must modify SPIHT’s encoder.
Outline • Wavelet Transform • SPIHT Coding • Error resilience: 1. Trees’ Partition and Packetization. 2. Multi-description in SPIHT • Channel • Error Concealment • Simulation • Future work
Error Concealment • Recovery of lost information (estimation). • Using correct information’s correlation. • There are three kinds of error concealment: 1.Spatial domain (video/image) 2.Temporal domain (video) 3.Frequency domain (video/image)
Our Error Concealment method • Using linear prediction to do error concealment. ( , ) • Minimum the mean square error • We can get • Using pixel’s correlation (the same position): 1.intra-subband (siblings) 2.inter-subband (parents’ correlation)
Intra-subband (siblings) • 1. Siblings’ direction ( ) • 2. Correlative siblings ( )
Inter-subband(parents’ correlation) (4,5) (4,20)
Reference compare (1).Our MDC and MD-SPIHT(A. C. Miguel) • MD-SPIHT: Copying every tree (20%,40% and 70%) • Our MDC :Copying lowest subband’s coefficients. (2).Our concealment and sequential error concealment (X. Li and M. T. Orchard) 1. Frequency domain and Time domain 2. Correlative position.
Outline • Wavelet Transform and SPIHT Coding • Error resilience: 1. Trees’ Partition and Packetization. 2. Multi-description in SPIHT • Error Concealment • Simulation • Future work
Simulation Methods • (一)Lossless:No packet loss。 • (二)Unprotected:Packets loss without protecting。 • (三)All Average:Using siblings’ average。 • (四)MDC+average(二):Lowest subband->MDC, sub-lowest subband->siblings’ average。 • (五)MDC+(intra):Lowest subband->MDC, sub-lowest subband->our concealment(intra-subband)。 • (六)MDC+(inter):Lowest subband->MDC, sub-lowest subband->our concealment(inter-subband)。
9/7 10 Packets loss 0.25bpp Lossless 32.59 db Unprotected 19.22db All Average 28.48 db MDC+inter 31.03 db MDC+intra 30.55 db MDC+average(二) 30.27 db
9/7 20Packets loss 0.25bpp Lossless 32.59 db Unprotected 15.35db All Average 25.42db MDC+(inter) 29.28db MDC+(intra) 29.07db MDC+average 28.55db
9/7 20Packets loss 0.25bpp Lossless 22.87db Unprotected 14.83db All Average 21.78db MDC+(inter) 22.18db MDC+(intra) 22.18db MDC+average 22.17db
Outline • Wavelet Transform • SPIHT Coding • Multi-description in SPIHT • Channel • Error Concealment • Simulation • Conclusion
Conclusion • In the lowest subband : MDC>Average (3db),(1db) • In the sub-lowest subband : Our concealment (intra)>Average (0.5db),(0.1db) Our concealment (inter)>Average (0.6~0.7db ) ( 0.1~0.2db) • Increasing by bitrate and packet loss rate. • In Lowest subband(MDC).(9/7 filter > 5/3 filter) • Sub-lowest subband( ourconcealment).(5/3 filter > 9/7 filter)
Thanks Everybody
9/7 10 Packets loss 0.25bpp Lossless 22.88 db Unprotected 17.76db All Average 22.41db MDC+inter 22.52 db MDC+intra 22.52 db MDC+average(二) 22.50 db
9/7 20Packets loss 0.25bpp Unprotected 15.35db All Average 25.42db MDC+average 28.55db MDC+(father) 29.72db MDC+(inter) 29.28db MDC+(intra) 29.07db