Human visual contrast detection of radial frequency stimuli defined by Bessel profiles j0,j1,j2,j4 ,j8,j16 and its relation to angular frequencies,

We measured human contrast sensitivity to radial frequencies defined as Bessel profiles of n-order, i.e. j₀, j₁, j₂,j₄,j₈,j₁₆. Six curves of 11 experimental conditions (each) were measured three times by three observers (NAS, MLS, FMR) using a forced-choice method. The results show that contrast sensitivity is increased with the j_n order for n greater than zero, having distinct orderly effects at the low and high frequency ends. We interpret these results as being most consistent with the possibility that a spatial frequency processing by the human visual system can be defined a priori in terms of polar coordinates