3D Forum 2006

THE FORUM FOR ADVANCEMENT OF THREE DIMENSIONAL IMAGE TECHNOLOGY AND ARTS
The 20th Anniversary of 3D Forum (The 77th Meeting)
University of Electro-Communications, Chofu, Tokyo, Japan
September 8, 2006

Anomalous motion illusion and stereopsis

Akiyoshi KITAOKA
(Department of Psychology, Ritsumeikan University, Kyoto, Japan)

since September 4, 2006 Paper (6.8MB) Handout (15.1MB)

"Doughnut of rotating snakes"

The image appears to move.

"Rotating snakes 3D #2"

If observers cross-fuse this autostereogram, six disks appear to be in front. Of them, the upper three appear to rotate clockwise while the lower three counterclockwise.

"Three-dimensionally rotating corrugated mesh"

This is an autostereogram. For uncross-fusers, the upper image appears to rotate clockwise along a vertical axis if it is observed from above while the lower image counterclockwise. For cross-fusers, the upper image appears to rotate counterclockwise along a vertical axis if it is observed from above while the lower image clockwise.

Handout (MS-Word doc file, 15MB)

"3D rotation of 3D-waving pattern"

This is an autostereogram, in which the image appears to wave in depth and rotate along a vertical axis.

Question: Can illusory motion alone give the illusory motion in depth?

"Sliding tiles 3D"

Motion illusion: The inset of the left image appears to slide rightward while that of the right image leftward.

Binocular stereopsis: When fusing the two images, cross-fusers see the inset in front of the surround, though there is no disparity between blue rectangles. The reversal is observed for uncross-fussers.¹⁾

¹⁾Gregory R L, Heard P F, 1983 “Visual dissociations of movement, position, and stereo depth” Quarterly Journal of Experimental Psychology 35A 217-237

Answer: Illusory motion alone cannot give the illusory motion in depth! (If any, it's very weak)

"Illusion buildings"

Motion illusion: In the left building, the upper half appears to move leftward while the lower half rightward. The reversal appears in the right building.

Position illusion: The blue windows are aligned vertically, but in the left building the ones in the upper half appear to be slightly shifted rightward as compared with those in the lower half. The reversal appears in the right building.¹⁾

Binocular stereopsis: When fusing the two buildings, cross-fusers see the lower half appears to be in front of the upper half. The reversal is observed for uncross-fusers.¹⁾

¹⁾Gregory R L, Heard P F, 1983 “Visual dissociations of movement, position, and stereo depth” Quarterly Journal of Experimental Psychology 35A 217-237

My opinion: Nevertheless, I claim there may be some relationship between anomalous motion illusion and stereopsis

Topic 1: What is anomalous motion illusion?

In this talk, anomalous motion illusion refers to illusory motion in a stationary image.

Example

Ouchi illusion (Ouchi, 1977; Spillmann et al., 1986)

The inset appears to move.

Ouchi, H. (1977) Japanese optical and geometrical art. Mineola, NY: Dover.

Spillmann, L., Heitger, F. and Schuller, S. (1986) Apparent displacement and phase unlocking in checkerboard patterns. Paper presented at the 9th European Conference on Visual Perception, Bad Nauheim

My classification of anomalous motion illusions

Topic 2: Optimized Fraser-Wilcox illusion

Fraser-Wilcox illusion (Fraser and Wilcox, 1979)

Fraser, A. and Wilcox, K. J. (1979) Perception of illusory movement. Nature, 281, 565-566.

Optimization of the Fraser-Wilcox illusion (Kitaoka and Ashida, 2003)

Kitaoka, A. and Ashida, H. (2003) Phenomenal characteristics of the peripheral drift illusion. VISION (Journal of the Vision Society of Japan), 15, 261-262

Classification of the optimized Fraser-Wilcox illusion
(September 2006 version)

Optimized Fraser-Wilcox illusion Type I Example

"The time tunnel show"

Rings appear to rotate.

Optimized Fraser-Wilcox illusion Type IIa Example

"Brownian motion"
(a remake)

Particles appear to move.

Optimized Fraser-Wilcox illusion Type IIb Example

"Hatching out"

Wings appear to expand. In addition, the illusory motion in the opposite direction can be observed when observers keep blinking.

Optimized Fraser-Wilcox illusion Type III Example

"Urban railways"

The upper two rows appear to move rightward while the lower two ones appear to move leftward.

In this talk, Type IIa and Type IIb are focused on.

"Blue octopus Tako-no-hacchan"

Each disk appears to expand.

Topic 3: Reversed phi movement

Reversed phi movement (Anstis, 1970)

Anstis S M, 1970 "Phi movement as a subtraction process" Vision Research 10 1411-1430

Standard (stroboscopic) reversed phi

Phenomenal phenomena (Gregory and Heard, 1983)

Gregory R L, Heard P F, 1983 "Visual dissociations of movement, position, and stereo depth" Quarterly Journal of Experimental Psychology 35A 217-237

"Phi movement" (Anstis and Rogers, 1975)

Anstis S M, Rogers B J, 1975 "Illusory reversal of visual depth and movement during changes of contrast" Vision Research 15 957-961

Further demonstrations

For demonstration, see Animation 8 of this animation page attached to the paper below.

------------------------

Kitaoka, A. (2006) Configurational coincidence among six phenomena: A comment on van Lier and Csathó (2006). Perception, 35, 799-806.

Shapiro, A. G., Charles, J. P., & Shear-Heyman, M. (2005). Visual illusions based on single-field contrast asynchronies. Journal of Vision, 5(10), 764-782

For demonstration, see Animation 8 of this page.

My explanation of the reversed phi movement

cf. the accepted explanation

Standard (stroboscopic) reversed phi

Stereopsis in this situation

(a) The Gregory-Heard stereopsis agree with the positional illusion, but disagree with phenomenal phenomena.
(b) The Anstis-Rogers stereopsis disagree with the positional illusion, but agrees with reversed phi.

For the full legend, see Figure 5 in kitaoka3D2006.doc.

(Luminance-change-dependent motion illusion Type A = Reversed phi and phenomenal phenomena)

(Luminance-change-dependent motion illusion Type B = "phi movement"

Summary: (1) The optimized Fraser-Wilcox illusion Type IIa agrees with reversed phi and phenomenal phenomena, and agree with the Anstis-Rogers stereopsis, but disagree with the positional illusion or the Gregory-Heard stereopsis.
(2) The optimized Fraser-Wilcox illusion Type IIb agrees with "phi movement", the positional illusion and the stereopsis.

But,

My view: I have failed to propose critical evidence for the relationship between anomalous motion illusion and stereopsis.

But,

My speculation: There are neurons that have a receptive field of three subfields, being a thin field flanked by thick fieds of different luminance profiles. Moreover, activity of such neurons underly a variety of visual effects or illusions ranging the perception of motion, position, or stereopsis.

Thank you.