An Efficient Spatial Prediction-Based Image Compression Scheme Chin-Hwa Kuo, Tzu-Chuan Chou, and Tay-Shen Wang, IEEE Transactions on Circuits and System for Video Technology, Vol.12, No.10, October 2002, pp. 850-856 Advisor : Prof. Chang, Chin-Chen Speaker: Lee, Jiau-Yun Date : 2003/6/3

Outline Introduction Spatial Prediction-Based Image Compression Proposed Spatial-Prediction Scheme Experimental Results Conclusions

Introduction DWT has become the important technology of image compression. ESPIC can fit for the application to real-time and wireless multimedia environment.

The Typical Spatial Coding System Symbol encoder compressed image + - Input image Nearest integer predictor decompressed image Compressed image Symbol decoder + predictor Prediction error

Spatial Prediction-Based Image Compression The typical spatial coding system can’t use all pixel to predict. We break the limit and extend to lossy image compression. c b a x

Proposed Spatial-Prediction Scheme(ESPIC) The design efficient spatial prediction-based image compression(ESPIC) consists two phases: Phase1---Prediction Construct hierarchical structure Prediction scheme Phase2---Quantization

Construct Hierarchical Structure Step1:mark position as n (row num.+column num.=even) Step2:mark position as n+1 (row num. :even & column num. :odd) preprocess: Set all pixels as 0 and n=1 0 1 2 3 4 5 6 7 1 2 1 2 3 4 5 6 7

Construct Hierarchical Structure(Cont.) 0 1 2 3 4 5 6 7 1 2 3 4 5 6 1 2 3 4 5 6 7 Step3: collect still marked as 0 and combine them into a new small image Step4: reassign new row and column num. Step5: n=n+2 go to step1 0 1 2 3 3 4 1 2 3 5 6

Construct Hierarchical Structure(Cont.) temporary map 1 2 3 4 5 6 Level4 Level3 Level2 Level1 5 5 6 4 4 4 4 3 3 3 3 1 1 1 1 2 2 2 2 Position number 1 32 2 16 3 8 4 4 5 2 6 1

Prediction Scheme---Mark Number n is odd number: n+1: <temporary map>

Example---Sender <original> 1 2 3 4 5 6 7 1 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7 100 120 80 70 90 200 50 220 110 60 30 1 2 1 2 3 4 5 6 7 10 32.5 17.5 40 37.5 62.5 55 -7.5 -5 -12.5 -40 -42.5 -20 -25 15 57.5 87.5 -57.5 -105 -52.5 -102.5 -35 -80 -82.5 70 100 -15 -30 7.5 -2.5 -22.5 1 2 3 4 5 6 7 0 = 80-(1/4(100+80+70+70)) -102.5 = 50-(1/4(90+220+100+200))

0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7 100 120 80 70 90 200 50 220 110 60 30 1 2 3 4 5 6 7 1 2 3 4 3 4 10 32.5 17.5 40 37.5 62.5 55 2.5 -25 -17.5 -7.5 -5 -12.5 -40 -42.5 -20 15 57.5 80 87.5 -57.5 -105 -52.5 -102.5 -35 -80 -82.5 102.5 70 125 100 -37.5 5 -15 -30 7.5 -2.5 -22.5 1 2 3 4 5 6 7 -12.5=90-(1/4(70+90+220+200)) 5=100-(1/4(200+90+60+30))

0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7 100 120 80 70 90 200 50 220 110 60 30 1 2 3 4 5 6 7 1 2 3 4 5 6 3 4 10 32.5 17.5 40 37.5 62.5 55 2.5 -25 -17.5 -7.5 -5 -12.5 -40 -42.5 -20 15 140 57.5 80 87.5 -57.5 -105 -52.5 -102.5 -35 -80 -82.5 102.5 70 125 100 -37.5 5 -15 -30 7.5 -2.5 60 -22.5 -100 5 6 1 2 3 4 5 6 7 -40=90-(1/2(200+60)) 140=200-60

Example---Receiver 1 2 3 4 5 6 7 1 2 3 4 5 6 7 5 6 200 = 60+140 0 1 2 3 4 5 6 7 1 2 3 4 5 6 1 2 3 4 5 6 7 10 32.5 17.5 40 37.5 62.5 55 2.5 -25 -17.5 -7.5 -5 -12.5 -40 -42.5 -20 15 140 57.5 80 87.5 -57.5 -105 -52.5 -102.5 -35 -80 -82.5 102.5 70 125 100 -37.5 5 -15 -30 7.5 -2.5 60 -22.5 -100 1 2 3 4 5 6 7 3 4 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7 90 200 60 30 5 6 200 = 60+140 90 = -40+(1/2(60+200))

10 32.5 17.5 40 37.5 62.5 55 2.5 -25 -17.5 -7.5 -5 -12.5 -40 -42.5 -20 15 140 57.5 80 87.5 -57.5 -105 -52.5 -102.5 -35 -80 -82.5 102.5 70 125 100 -37.5 5 -15 -30 7.5 -2.5 60 -22.5 -100 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 2 3 4 5 6 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7 70 90 200 220 100 60 30 3 4 220 = 125+ (1/4(90+60+30+200))

Quantization The higher level pixels affect more pixels They have higher significance. The hierarchy is similar to the hierachy made by DWT. The authors combine prediction scheme and SPIHT algorithm. It can use progressive codec.

Quantization Round1: pass 60,140,0,0 … 1 2 3 4 5 6 7 10 32.5 17.5 40 37.5 62.5 55 2.5 -25 -17.5 -7.5 -5 -12.5 -40 -42.5 -20 15 140 57.5 80 87.5 -57.5 -105 -52.5 -102.5 -35 -80 -82.5 102.5 70 125 100 -37.5 5 -15 -30 7.5 -2.5 60 -22.5 -100 1 2 3 4 5 6 7 Round1: pass 60,140,0,0 …

Experimental Results

Experimental Results(Cont.)

Conclusions The ESPIC scheme has compression efficiency and progressive coding. The developed scheme is benefit to the application of real-time and wireless image transmission.