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Andy Resnick
#77
Oct11-11, 08:25 AM
Sci Advisor
P: 5,508
Quote Quote by sophiecentaur View Post
You made a statement about perceived sharpness being related to level. <snip>.
If I did, that was not my intention. In terms of linear systems analysis, the perceived (meaning visual appearance) sharpness of an image is set by the contrast at midrange spatial frequencies. The cutoff frequency (the 'resolution limit') is less important to the visual appearance than the contrast at midrange spatial frequencies.

There is an excellent discussion of this (contrast sensitivity function) in "Basic Vision" (Snowden, Thompson, and Troscianko)