Abstract
It has already been shown that the sharpness evaluation method based on the cooperative human vision model is superior in performance to conventional methods. In order to clarify factors of the vision-model-based method's high performance, the conventional metrics are improved so that they reproduce fundamental characteristics on sharpness in the same way as the vision-model-based metric, and then the performance of the improved metrics is compared with that of the vision-model-based metric. Consequently, the following results were obtained: (1) the improvement was achieved by utilizing the Fourier transform of imaging system's output images instead of the imaging system's MTF; (2) the vision-model-based metric was superior in evaluation performance to the improved metrics. Considering that one large difference between the two kinds of metrics consists in the existence of the image observing mechanism, these results suggest that the model's image observing mechanism can be a factor of the vision-model-based method's high performance.
