Universität Mannheim
Fakultät für Sozialwissenschaften
 
Moving Circular Grating

Professur für
Allgemeine Psychologie

Prof. Dr. Hans Irtel

Sinusoidal Gratings

 
 

Gray Level Gratings

 

Here are some gray level gratings with low average (LA) and high average (HA) luminance and low (LF) and high (HF) spatial frequency. Furthermore the gratings can have high (HC) or low (LC) contrast.

LC HC
HA LF
HA HF
LA LF
LA HF

 
 

Chromaticity Gratings

 
From Red to Green From Blue to Yellow
LF
HF
 
 

A Moving Grating

 
 
 

Want to See Your Modulation Transfer Function

 
Grating detection depends on the grating's spatial frequency and its modulation depth. A function which describes the transfer of the physical description of a grating into perceived properties may be called "visual modulation transfer function", a term which is used in systems theory to describe linear systems. A nice approximation to ones own visual modulation transfer function can be seen when looking at a grating whose spatial frequency increases in the horizontal direction and whose modulation depth decreases in the vertical direction.

Look at the image and try to see the hull of the area which contains some intensity modulation. The horizontal axis corresponds to a log frequency scale while the vertical axis corresponds to decreasing modulation and thus to sensitivity. The apparent border between visible and invisible modulation corresponds to your own visual modulation transfer function.

 
 

Where do the gratings come from?

 
All the gratings on this page have been generated by the program MVG from the author's PXL library. The gratings were generated by using MVG's -G option and then loading the resulting GIF files into Alchemy Mindworks' GIF Construction Set Animation Wizard.

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