pals (version 1.5)

pal.csf: Show a colormap with a Campbell-Robson Contrast Sensitivity Chart

Description

In a contrast sensitivity figure as drawn by this function, the spatial frequency increases from left to right and the contrast decreases from bottom to top. The bars in the figure appear taller in the middle of the image than at the edges, creating an upside-down "U" shape, which is the "contrast sensitivity function". Your perception of this curve depends on the viewing distance.

Usage

pal.csf(pal, n = 150, main = "")

Arguments

pal

A continuous colormap function

n

The number of colors to display for palette functions.

main

Main title.

Value

None

Details

What to look for:

1. Are the vertical bands visible across the full vertical axis?

2. Do the vertical bands blur together?

References

Izumi Ohzawa. Make Your Own Campbell-Robson Contrast Sensitivity Chart. http://ohzawa-lab.bpe.es.osaka-u.ac.jp/ohzawa-lab/izumi/CSF/A_JG_RobsonCSFchart.html

Campbell, F. W. and Robson, J. G. (1968). Application of Fourier analysis to the visibility of gratings. Journal of Physiology, 197: 551-566.

Examples

# NOT RUN {
pal.csf(brewer.greys) # Classic example from psychology
pal.csf(parula)

# }

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