New objective performance evaluation criteria for imaging systems based on a human vision model and their fundamental characteristics

Abstract

Three new objective performance evaluation criteria, C/Vn (Carrier to Visual noise ratio), N/Vn (Noise to Visual noise ratio), and C/N (Carrier to Noise ratio), for imaging systems are proposed. These criteria are quantified based on visual noise characteristics derived from a human vision model formulated by the author; in an output image from imaging systems, to which a sine-wave is inputted, C/Vn and N/Vn are defined, respectively, as the quantity of the perceptible sine-wave component with the frequency equal to the input sine-wave and as the quantity of all the perceptible noise components, and C/N is a simplified expression for integrating C/Vn and N/Vn. These criteria are applied to the performance evaluation of imaging systems based on the density-gradation-method such as CRTs, LCDs, printers and so on. They are calculated as parameters of pixel aperture ratio, quantizing level number, and pixel size. In actual computation, pulse-amplitude-modulated sinusoidal waves are used as output images from such imaging systems. The calculated fundamental characteristics suggest that the objective performance evaluation criteria are effective in quantitatively expressing human subjective evaluation judgments.