The effect of coma and astigmatism on subjective quality of image of sinusoidal and square-bar targets is simulated by using digital processing system. A suprathreshold method is employed in psychophysical discrimination experiments. We determine the robustness of some image quality metrics that can be employed during automated production of visual instruments by examining the correlation between subjective results and objective measures. These include the variance of the wavefront aberration, the Strehl ratio, the radius of 84% encircled energy of the point spread function (R84), the modulation transfer function (MTF) and the integral of the MTF across the frequency range of interest (MTFa). For the target orientation that is most affected by the aberrations, we find that MTFa and R84 give good correlation with subjective result, while the Strehl ratio and the variance do not. In addition, we find that the MTFa correlates with subjective results for all orientations.
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Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Zhang, Hongping, "Image quality metrics for visual optical instruments" (1991). Thesis. Rochester Institute of Technology. Accessed from
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