I find this Checkershadow illusion of Edwards incredible. Can “A” really be the same shade and color as “B”? He uses shadows and neighboring colors to deceive the eye in regards to the shade of gray “paint” that belongs to the surface. Edward did a nice job in creating the visual color illusion in this figure.
About the Checkershadow Illusion
I have learned that the first trick used here is based on local contrast. A check that is lighter than its neighboring checks appears lighter than average and vice versa. The second trick is based on the fact that shadows often have soft edges, while paint boundaries like the checks have sharp edges. Thirdly, the “plainness” of the checks is aided by the form of the “X-junctions” formed by 4 adjoining checks. This type of junction is usually a signal that all the edges should be interpreted as changes in surface color rather than in terms of shadows or lighting.
About the Author
Edward H. Adelson has over 100 publications on topics in human vision, machine vision, computer graphics, neuroscience, and computational photography. He is well known for contributions to multi-scale image representation such as the Laplacian pyramid and basic concepts in early vision such as steerable filters and motion energy models. His work on layered representations for motion won the IEEE Computer Society’s Longuet-Higgins Award in 2005. Adelson introduced the plenoptic function and built the first plenoptic camera. His work on the neural mechanisms of motion perception was honored with the Rank Prize in Optoelectronics in1992.
Edward has done pioneering work in computational photography, including early work on image merging and more recent work on high dynamic range imaging. In computer graphics, he has worked on the generation and perception of line drawings. He currently works on perceptual and computational aspects of material perception including the perception of gloss. Edward has produced some well-known illusions such as the Checker-Shadow Illusion. He has recently developed a new elastomeric technology for tactile sensing, called GelSight, which converts touch to images, and which opens up new possibilities in sensing 3D microscale topography.
Thank you very much Edward H. Adelson for allowing us to post and share your Checkershadow Illusion. If you wish to know more about his interesting works, you can go and visit his website.