Fig. 1
From: A power law study of the edge influence on the perceived filling-in brightness magnitude
A sample of the subject’s viewing conditions. On the rows, we can see different levels of edge filtering in which a is the higher filtering (σ = 1.5), b is the medium filtering (σ = 0.8), and c is the lower filtering (σ = 0.3). From left to right columns are the samples of high, medium, and low luminance levels. The right circle with a sharped edge is the reference circle, and both circles had the same luminance