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Investigating PSNR, VDP, and SSIM metrics in relation to Weber's law and human visual system for image quality assessment.
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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