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Analysis and Comparison of Quality Metrics with Reference Based on Uniform Color Spaces. EUVIP 2010. Gabriel Dauphin, Patrick Viaris de Lesegno L2TI, Institut Galilée, Université Paris 13. Outline. Three quality metrics are studied : PSNR, VDP, SSIM. Analytic. Experience. IV.
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Analysis and Comparison of Quality Metrics with Reference Based on Uniform Color Spaces EUVIP 2010 Gabriel Dauphin, Patrick Viaris de Lesegno L2TI, Institut Galilée, Université Paris 13
Outline • Three quality metrics are studied : PSNR, VDP, SSIM Analytic Experience IV • Are they consistent with Weber’s law? • Is Weber’s law consistent with HVS? I V II III
Consistent with Weber’s Law? I • . • VDP • SSIM
Color Spaces and Gamma Correction Say NO II • CIE L*a*b* 1976 : • Gamma Correction
65 29 Psychovisual Tests Say NO III 147 [Y.-K. Lai and C.-C.J. Kuo 2000]
IV New Photometric Invariance Law • Q consistent with HVS wrt its sensitivity to backgound Lum. • Q consistent with Weber’s law
Numerical Simulations V VDP:a=-0.04 PSNR:a=0.42 SSIM SSIM: PSNR => Yes VDP, SSIM => No
Conclusion • Weber’s law => VDP,SSIM[Ci=0] HVS • Photometric invariance law and simulation tool • Yet Weber’s contrast may improve rendering => this should be application driven • Many aspects of image processing are already consistent with HVS => good news for quality assessment