In some research, I have found that the perceived quality of an image is linearly related with the square root of the normalized modulation.
Perceived contrast of sinusoidal luminance patterns is linearly proportional with the square root of the normalized modulation. This image quality metric is called SQRI - square-root integral.
Has anyone ever seen a practical application of using SQRI for judging the perception of an image from the human eye?
Experimental data on subjective image quality at varying resolution, addressability, luminance and display size are compared with predictions by the square root integral. From the comparison it appears that there is a linear relation between subjective image quality and SQRI value.
Consequently, the SQRI metric is recommended over both the ICS and MTFA metric in predicting observed subjective image quality for human visual systems (over computational/algorithmic means.)
Ref: The proceedings of the SPIE Volume 1077, Human Vision, Visual Processing, and Digital Display (1989); doi 10.1117/12.952705
Author: Peter G. J. Barten
