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Improvements to the JPEG-LS prediction scheme. Authors: S. Bedi, E. A. Edirisinghe, and G. Grecos Source : Image and Vision Computing. Vol. 22, No. 1, 2004, pp. 9-14 Speaker: Chia-Chun Wu ( 吳佳駿 ) Date : 2004/09/15. Outline. JPEG-LS prediction scheme Improvements JPEG-LS
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Improvements to the JPEG-LS prediction scheme Authors:S. Bedi, E. A. Edirisinghe, and G. Grecos Source : Image and Vision Computing. Vol. 22, No. 1, 2004, pp. 9-14 Speaker:Chia-Chun Wu (吳佳駿) Date : 2004/09/15
Outline • JPEG-LS prediction scheme • Improvements JPEG-LS • Our method • Sample images • Experimental results • Comments
JPEG-LS prediction scheme JPEG-LS predictive template
Improvements JPEG-LS Diagonal edge T1=20, T2=0
Sample images Airplane Baboon
Sample images Barb Boat
Sample images Girl Gold
Sample images Lena Lenna
Sample images Pepper Sailboat
Experimental results Predictive mean squared error N = 9
Experimental results Table 1 Lossless compression ratios of all test images (Unit: Bytes)
Experimental results Table 2 Lossless compression ratios of all test images (Unit: Bytes)
Experimental results Table 3 PMSE values of all test images (T1=20, T2=0)
Experimental results Table 4 PMSE values of all test images (T1=20, T2=0)
Comments • 本篇論文的預測方法,獲得的PMSE整較傳統的JPEG-LS好,但是影像整體的壓縮率卻沒有明顯的提升。 • 跟傳統的JPEG-LS及本篇論文的方法比較,目前我們提的預測方法,並沒有提升預測的準確度及影像的壓縮率。
Source Code if (Rc >= MAX(Ra,Rb)) Px = MIN(Ra,Rb); else if (Rc <= MIN(Ra,Rb)) Px = MAX(Ra,Rb); else Px = (Ra + Rb - Rc); Errval = (Ix - Px); PMSE = PMSE+ (Errval*Errval);
Source Code if ( (((Rc -MAX(Ra,Rb)) > Threshold1) || ((MIN(Ra,Rb)-Rc) > Threshold1)) && (ABS(Ra-Rb) <= Threshold2) ) { Px=(Ra + Rb + Rd)/3; } else if (Rc >= MAX(Ra,Rb)) Px = MIN(Ra,Rb); else if (Rc <= MIN(Ra,Rb)) Px = MAX(Ra,Rb); else Px = (Ra + Rb - Rc); Errval = (Ix - Px); PMSE = PMSE+ (Errval*Errval);
Source Code Px = (Ra + Rb + Rc) /3; Errval = (Ix - Px); PMSE = PMSE+ (Errval*Errval);