Support for ECVP2006 abstract: ' Increasing and decreasing the Chevreul illusion by a background luminance ramp'

J Geier, L Séra, L Bernáth, M Hudák
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Images are available only for ECVP2006 committee and reviewers.
Copyright © 2006,  Janos Geier and his coworkers, All rights reserved. 

HTML programmer: Mariann Hudák, image programmer: János Geier

                           Description of the Images

		Images presented on this site are demonstrations only.
		The Chevreul illusion is a luminance staircase comprising homogeneous grey steps whose border neighbouring a  lighter step appears to be darker.
		The luminance staircase is placed either in a luminance ramp background or a homogeneous grey or black background

Click on the images to enlarge.

• All these images are gridled with a larger luminance background ramp

Click on the images to enlarge.

What to observe?

• If the orientation of the luminance change of the inner luminance ramp is identical with that of the staircase, the Chevreul illusion increases and the steps are perceived nearly identical in luminance. (Inner1, lower luminance staircase)
• If the same staircase is flipped horizontally, so that the direction of its luminance change is opposite to that of the luminance ramp surrounding it, the Chevreul illusion ceases. (Inner1, upper luminance staircase)
• When inserting the previous images into another luminance ramp as background, it has no effect on the perception of the innermost luminance staircase. (Inner1Outer1, Inner2Outer1, Inner3Outer1)

Conclusion

• Edges behave as segment boundaries, and the impact of the background ramp infiltrates only through one segment boundary.

For further information see  

  (since April 13, 2006)