For most tasks of image evaluation, the human observer is very versatile and reliable. So he could be used as a good standard to measure the performance of technical image evaluation systems. However, to proceed in that way seems to be difficult since the human observer is open to many so-called subjective influences.
R.H. A. Rohler,
"Human Image Evaluation, Hypothesis Formation And Threshold", Proc. SPIE 0467, Image Assessment: Infrared and Visible, (14 May 1984); doi: 10.1117/12.941576; https://doi.org/10.1117/12.941576