1. Progressive medical image transmission and compression
Author : R. S. Dilmaghani, A. Ahmadian, M. Ghavami, A. H. Aghvami
Source : IEEE Signal Processing Letters, Volume. 11, No. 10
Speaker : Pay-Chai Chang (張培才)

2. Outline Introduction Introduction to EZW Resolution Constraint
Bit-Rate Constraint
Progressive Transmission of a ROI of an Image
Conclusion

3. Introduction (1/2) 離散小波轉換 a+b c+d a-b c-d a b c d A B C D A B C D20 15 30 17 16 31 22 18 25 21 19 35 50 5 10 33 53 1 9 42 3 -8 43 37 -1
A B C D
A B C D
A+B C+D A-B C-D 68
103 6 19 76 79 2 -7 -3 4 1
-10 5 -9
326
-38 6 19 16
-32 2 -7 -3 4 1
-10 5 -9

4. Introduction (2/2) LL1 HL1 LH1 HH1 第一階 第二階 第三階 影像最重要 的部分 HL2 LH2 HH2

5. Introduction to EZW (1/5)
T0 =2 log2(max(Cij)) = 2 log263 = 25 = 32
R = (max(Cij) + T0 ) / = ( ) / 2 = 48
POS (ex : 63)
NEG (ex : -34)
ZTR (ex : 23)
IZ (ex : -31)

6. Introduction to EZW (2/5)63
R2=40
R1=56 D1 S1
A1 = 0 (之前的重要係數)
Max (Cij)

7. Introduction to EZW (3/5)
T1 = T0 / = 32 / 2 =16
R = 48 / 2 = 24 A2 S2
直到 Tk = 0 或使用者認為可以為止

8. Introduction to EZW (4/5)
Max (Cij)(63) => T0 => R(48) => R1(56) , R2(40)
D1 : POS,NEG, IZ, ZTR, POS, ZTR, ZTR, ZTR, ZTR, IZ, ZTR, ZTR, ZTR, ZTR, ZTR, ZTR, ZTR, POS, ZTR, ZTR S1 : A1 = 0

9. Introduction to EZW (5/5)
A2 = 1001

10. Resolution Constraint (1/3)
Resolution Constraint specified the maximum number of scales or subbands to be scanned and refined during zerotree passes.
Bit rate (EZW編碼結果所佔大小)
Scale 1 2 3 4 5…
Resolution(I)
2-1
2-2
2-3
2-4
2-5

11. Resolution Constraint (2/3)
LL3
HL1
LH1
HH1
HL2
LH2
HH2
LL2
HL1
LH1
HH1
HL2
LH2
HH2
LL2
Scale : 2 , I = 2-2
Scale : 3 , I = 2-3
PSNR , bit rate : scale 2 > scale 3
仍使用threshold 來達成漸進式傳輸 多使用了 resolution 來限制

12. Resolution Constraint (3/3)

13. Bit-Rate Constraint (1/2)
設定 Bit-Rate Constraint , 各 resolution 掃描到該值則停止

14. Bit-Rate Constraint (2/2)

15. Progressive Transmission of a ROI of an Image

16. Conclusion
The results shows that the compression performance obtained by the EZW is superior over JPEG-2000, especially at higher compression ratios.