錯視と脳と視覚心理学

問：　下記のような色から、オレンジ色と赤紫色を同時に作る方法はあるか？

左の「色材」は赤が赤紫とオレンジに見え、「研究」は水色と黄緑色に見える。右の「色材」は灰色が赤紫とオレンジに見え、「研究」は青緑色が水色と黄緑色に見える。

問：お月様と同じ物理的な色をしている円は下の3つのうちどれでしょう。

青フィルターがかかっていやな感じではあるが金閣は金色に見える。金色は黄色系統でなければならないという前提があるなら、この合成画像で金閣が金色に見えることは錯視であり、知覚される金色は物理的には青系統の色である。

北岡明佳　（2011）　色の錯視いろいろ　（1）「目の色の恒常性」という錯視の絵　日本色彩学会誌, 35(2), 118-119. PDF（スキャンコピー）

北岡明佳　（2011）　色の錯視いろいろ　（2）色の恒常性と2つの色フィルタ　日本色彩学会誌, 35(3), 234-236. <図2>

北岡明佳　（2011）　色の錯視いろいろ　（2）色の恒常性と2つの色フィルタ　日本色彩学会誌, 35(3), 234-236. <図4>

２つの図を両眼融合して見ると、左目はオレンジ色と緑色の間の両眼闘争を起こすが、右目は黄色に見えたままである。しかし、右目は左目と同じく、物理的にはオレンジ色と緑色なのである。

色の恒常性は高次な知覚という先入観が私にはあったが、本図は低次処理の証拠となるかもしれない。

２つの図を両眼融合して見ると、右目はシアン色（水色）と赤色の間の両眼闘争を起こすことがあるが、左目は灰色に見えたままである。しかし、どちらの右目も左目と同じく、物理的には灰色なのである。

両眼の情報が統合される前に色の恒常性が成立していないと両眼闘争はしないよね・・・その論理でいいのか？？

Chromostereopsis. For the majority of observers, the inset made up of red random dots appears to be in front of the surround constituted of blue ones. For a minority, the inset appears to be behind the surround. The rest do not experience the phenomenon. Chromostereopsis is strong when observers see the image at a distance.

Artificial pupil method & Stiles-Crawford effect
---> Vos' (1960, 2008) "generalised Bruecke-Einthoven explanation"

Kitaoka, A, Kuriki, I. and Ashida, H. (2006). The center-of-gravity model of chromostereopsis. Ritsumeikan Journal of Human Sciences, 11, 59-64. PDF

手前の山は「筆ノ山」（ふでのやま）、奥の山は「我拝師山」（がはいしやま、がはいしざん）と思われる。

北岡明佳のコメント：　Adelson-Anandan-Andersonのモデルで言えば、bistable transparency （両義的透明視あるいは二値安定透明視あるいは反転可能透明視）である。

なお、「透明に見える山」の報告はこれが初めてではなく、池田（1993）（関西大学『社会学部紀要』第25巻第1号pp.165-168）によると、大阪府吹田市の一角から遠望した山に見えるとして、写真が載っている。その池田によると、Metzger (1953) に既に載っている。

Kitaoka, A. (2005) A new explanation of perceptual transparency connecting the X-junction contrast-polarity model with the luminance-based arithmetic model. Japanese Psychological Research, 47, 175-187. PDF

大阪城の天守閣からの眺めなので、いつでも見ることができる。大阪城にはエレベーターがあるので、登るのは楽である。なお天守閣は8階が最上階であるが、エレベーターは5階までである。なぜ途中までかというと、「大阪夏の陣の後、徳川家が再建した当時の技術では、エレベーターは5階までが限界だったから」と言っている人がいた。（オレや）

The term "spiral illusion" had long referred to the spiral illusion of the Fraser illusion (Fraser, 1908) before we elucidated that any tilt illusion can form spiral illusion (Kitaoka, Pinna and Brelstaff, 2001). This page shows a copy of Fraser's spiral produced by PC programming. <2003/8/30>

Kitaoka, A., Pinna, B., and Brelstaff, G. (2001). New variations of spiral illusions. Perception, 30, 637-646.

Concentric circles appear to be spirals (going to the center by rotating clockwise). Moreover, the inner part appears to rotate clockwise (counterclockwise) when observers approach (move away from) the image keeping their eyes fixed at the center.

Concentric rings appear to be spirals. Moreover, each set of rings appears to rotate.

Copyright Hitoshi & Shinobu Arai 2007
from Professor Hitoshi Arai, Graduate School of Mathematical Sciences, University of Tokyo, October 4, 2007

北岡明佳のコメント：　原理としてはフレーザー錯視のようですが、それよりもなによりも、世界初のフラクタル錯視図形なのではないでしょうか！？　新井先生の視覚数学e研究室報告に、この錯視の論文が出ました。 <2007年10月4日>

Kitaoka, A., Pinna, B., and Brelstaff, G. (2001). New variations of spiral illusions. Perception, 30, 637-646. PDF

Each disk appears to rotate clockwise on a bright display, while it appears to rotate counterclockwise with a printed image under dark illumination.

Each disk appears to rotate counterclockwise when this image is presented on a bright PC display or in a print with a bright environment.

Each disk appears to rotate clockwise when this image is presented on a bright PC display or in a print with a bright environment.

The disk appears to rotate clockwise when this image is presented on a bright PC display or in a print with a bright environment.

Each disk appears to expand when this image is presented on a bright PC display or in a print with a bright environment..

<Kitaoka, A. (forthcoming). The Fraser-Wilcox illusion and its extension. In Shapiro, A. and Todorovic, D. (Eds.), Oxford Compendium of Visual Illusions. Oxford University Press.>

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

Observers saw illusory motion in a stationary image which consists of repeated luminnace gradient in a saw-tooth wave form. Some reported illusory motion from dark to light along a luminance gradient, while others saw the reversal. The illusion is strong in the peripheral viewing. Fraser and Wilcox (1979) claimed that this individual difference depends on some genetic properties.

The left disk appears to rotate clockwise while the right one counterclockwise. Faubert and Herbert (1999) reported only illusory motion from dark to light along a luminance gradient. They attributed the illusory motion to the assumed time difference between responses to black and white.

Faubert, J. and Herbert, A. M. (1999). The peripheral drift illusion: A motion illusion in the visual periphery. Perception, 28, 617-621.

The left disk appears to rotate clockwise while the right one counterclockwise. Naor-Raz and Sekuler (2000), too, reported only illusory motion from dark to light along a luminance gradient. They revealed that the illusion magnitude is a positive, nearly linear function of contrast.

Naor-Raz, G. and Sekuler, R. (2000). Perceptual dimorphism in visual motion from stationary patterns. Perception, 29, 325-335.

The left disk appears to rotate counterclockwise while the right one clockwise. Kitaoka and Ashida (2003) proposed that the illusory motion is strong when patterns are arranged in the following luminance order: from black, dark-gray, white, light-gray, and back to black.

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

Kitaoka (2007) classified the Fraser-Wilcox illusion into Type I, IIa, IIb and III, in each of which the dark-to-light type was distinguished from the light-to-dark one.

Kitaoka, A. (2007) Phenomenal classification of the “optimized” Fraser-Wilcox illusion and the effect of color. Poster presentation in DemoNight, VSS2007, GWiz, Sarasota, Florida, USA, May 14, 2007.

"Dark to light"
The left disk appears to rotate counterclockwise while the right one clockwise.

"Light to dark"
The left disk appears to rotate counterclockwise while the right one clockwise.

"Dark to light" and "light to dark" combined
The left disk appears to rotate counterclockwise while the right one clockwise.

"Dark to light" and "light to dark" combined, with color enhancement
The left disk appears to rotate counterclockwise while the right one clockwise.

The upper-left, upper-right, and lower-middle disks appear to rotate counterclockwise while the rest clockwise.

Type IIa

The upper-left, upper-right, and lower-middle disks appear to rotate counterclockwise while the rest clockwise.

Type IIb

The upper-left, upper-right, and lower-middle disks appear to rotate counterclockwise while the rest clockwise.

The upper-left, upper-right, and lower-middle disks appear to rotate counterclockwise while the rest clockwise.

Kitaoka, A. (2008a). Optimized Fraser-Wilcox illusions: a pictorial classification by Akiyoshi Kitaoka. Talk in Workshop No.005 "Experimental studies of anomalous motion illusions" in the 72nd Annual Convention of the Japanese Psychological Association, Hokkaido University, Sapporo, Japan, September 19, 2008. Talk

Kitaoka, A. (2008b). A new type of the optimized Fraser-Wilcox illusion in a 3D-like 2D image with highlight or shade. Journal of Three Dimensional Images (Japan), 22(4), 31-32. PDF PDF (manuscript) Presentation

The upper-left, upper-right, and lower-middle rings appear to rotate counterclockwise while the rest clockwise.

In 2008, Kitaoka found that the direction of illusory motion is “red → dark purple → purple → magenta (light red-purple) → red”, and that the illusion magnitude is strong when overall luminance contrast is low. Images of high luminance make a strong effect.

Kitaoka, A. (2010). Introduction to visual illusion. Tokyo: Asakura-shoten (in Japanese). Book

Kitaoka, A. (2012a). Designs using the red Fraser-Wilcox illusion. Journal of the Color Science Association of Japan, 36, Supplement, 188-189. PDF (color manuscript) Talk

Kitaoka, A. (2012b) The Fraser-Wilcox illusion and its extension. Perception 41 ECVP Abstract Supplement, page 91 (Poster September 3, 2012). Poster PDF

In 2011, Kitaoka found that flickering the image increases the illusion magnitude. Blinks also work.

Flickering induction depends on the interaction between the stimulus and the blank.

Each disk appears to rotate clockwise during fading-in while counterclockwise during fading-out.

Each disk appears to rotate counteclockwise during fading-in while clockwise during fading-out.

Each disk appears to expand during fading-in while to contract during fading-out.

Yanaka and Hilano (2011) reported that this illusion is enhanced by mechanical shaking.

Each disk appears to rotate counterclockwise.
(Note that this movie is not their original)

Yanaka, K. and Hilano, T. (2011). Mechanical shaking system to enhance "Optimized Fraser–Wilcox Illusion Type V". Perception, 40, ECVP Abstract Supplement, page 171.

Yanaka (2012) reported that this illusion is enhanced by viewing images under dark illumination.

Yanaka, K. (2012). Enhancement of the optimized Fraser-Wilcox illusion Type V by swinging the image. Talk in the 5th Illusion Workshop, Meiji University, Tokyo, Japan, September 18, 2012.

In 2013, Kitaoka (ECVP2013) found that Yanaka’s darkening enhancement is accompanied by a reversal of illusion: i.e., the direction under dark condition is “red → magenta (light red-purple) → purple → dark purple → red”.

Kitaoka, A. (2013). Invisible color and visible color: Mystery of color the brain feels. Talk in the Shizuoka Science Museum Ru-Ku-Ru, Shizuoka, Japan, January 13, 2013. Talk

In 2013, Kitaoka (ECVP2013) found that combination of a long wavelength color and a short one makes the illusions.

Each disk appears to rotate clockwise on a bright display, while it appears to rotate counterclockwise with a printed image under dark illumination.

Each disk appears to rotate clockwise on a bright display, while it slightly appears to rotate counterclockwise with a printed image under dark illumination.

In 2013, Kitaoka (ECVP2013) found that increasing or decreasing illumination makes the illusions.

It is suggested that this ‘luminance change-induced’ motion* might generate the color-dependent Fraser-Wilcox illusion, being triggered by saccades, blinks, flickering or shaking the images.

*The luminance change-induced’ motion includes the reverse phi phenomenon (Anstis, 1970; Anstis and Rogers, 1975) and the phenomenal phenomena (Gregory and Heard, 1983). Directions of illusory motion depending on the changes of luminance are shown in the right (Kitaoka, 2006).

Anstis S M, 1970 “Phi movement as a subtraction process” Vision Research 10 1411-1430
Anstis S M, Rogers B J, 1975 “Illusory reversal of visual depth and movement during changes of contrast” Vision Research 15 957-961
Gregory R L, Heard P F, 1983 “Visual dissociations of movement, position, and stereo depth: some phenomenal phenomena” Quarterly Journal of Experimental Psychology 35A 217-237
Kitaoka, A. (2006). Configurational coincidence among six phenomena: A comment on van Lier and Csathó (2006). Perception, 35, 799-806. animations --- PDF

Configurational coincidence among six phenomena: A comment to van Lier and Csathó (2006)

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

Reversed phi movement (Anstis and Rogers 1975). There are four rectangles, each of which is flanked by thin lines that are dark or light. When the luminance of the rectangles decreases and that of the background increases accordingly, the upper two appear to converge in motion while the lower two appear to go apart in motion. On the other hand, when the luminance of the rectangles increases and that of the background decreases accordingly, the upper two appear to go apart in motion while the lower two appear to approach each other in motion. In sum, the direction of apparent motion is from the dark flank to the neighboring part that goes darkening or from the light flank to the neighboring part that goes brightening. Although the rectangles are aligned vertically, the apparent positional displacement occurs in the opposite direction to motion. If observers cross-fuse (uncross-fuse) the right and left rectangles, the upper rectangle appears to be in front of (behind) the lower one when they are dark.

The illusory motion investigated by Gregory and Heard (1983). This appearance is quite similar to Animation 1. The only configurational difference from the reversed phi movement is that the luminance of the rectangles is constant.

The illusory motion mentioned by Gregory and Heard (1983), in which the luminance of the rectangles dynamically changes while that of the surround is constant. This appearance is quite similar to Animations 1 and 2.

Phi movement (Anstis and Rogers 1975). For panel (a), dark stationary rectangles are placed on a bright stationary background. When the luminance of the right flank of each rectangle increases and that of the left flank decreases, the rectangle appears to shift leftward in motion as well as in position. Conversely, the luminance of the right flank decreases and that of the left flank increases, the rectangle appears to shift rightward in motion and position. If observers cross-fuse (uncross-fuse) the right and left rectangles, the fused rectangle appears to be in front (behind) when the right flank of the right rectangle are dark and the left flank of the left rectangle are dark. For panel (b), bright rectangles are placed on a dark background. In this case, phenomena are the reversal of panel (a).

Consistency between the reversed phi movement and stereopsis (Anstis and Rogers 1975). In this animation, there are two phases in motion, in which the upper-left and the lower-right rectangles are one eighth phase in advance of the upper-right and the lower-left rectangles. For example, when the luminance of the rectangles increases, the upper-left rectangle appear to go leftward followed by the upper-right one, while the lower-right rectangle appear to go leftward followed by the lower-left one. In this period, the cross-fused (uncross-fused) upper rectangle appears to be in front (behind) as compared with the cross-fused (uncross-fused) lower rectangle.

Consistency between the apparent motion and Café-Wall-like tilt illusions (van Lier and Csathó 2005). According to dynamic changes in luminance gradient, the flanks of the rectangle appears to tilt dynamically. (a) The luminance gradient given to both flanks is dynamically changed while the dark-gray rectangle and the light-gray background are stationary. The dark part of the gradient appears to shift outward in motion and position while the bright part appears to shift inward in motion and position. This distortion agrees with the tilt illusion. (b) The luminance gradient given to the rectangle is dynamically changed while the dark flanks and the gray background are stationary. At the dark part of the gradient, the neighboring part of flanks appears to shift inward in motion and position, while at the bright part of the gradient, the neighboring part of flanks appears to shift outward in motion and position. This distortion agrees with the tilt illusion.

Inconsistency between the apparent motion and Café-Wall-like tilt illusions. According to dynamic changes in homogenous areas, the flanks of the rectangle appears to tilt dynamically. (a) The luminance of the homogeneous rectangle is dynamically changed while the flanks with luminance gradient and the gray background are stationary. The darkening rectangle appears to attract the dark parts of the flanks inward in motion while the brightening rectangles appears to attract the light parts of the flanks inward in motion. This distortion disagrees with the tilt illusion. (b) The luminance of the homogeneous flanks is dynamically changed while the rectangle with luminance gradient and the gray background are stationary. At the dark part of the gradient, brightening flanks appears to shift inward in motion, while at the bright part of the gradient, darkening flanks appears to shift inward in motion. This distortion disagrees with the tilt illusion

Demonstration of the apparent motion in the three elemental spatio-temporal configurations (Figure 6). The behaviors in (a), (b) and (g) are summarized in Figure 6a (off-center line-type configuration); those in (c), (d) and (h) are in Figure 6b (on-center line-type configuration); and those in (e), (f) and (i) are summarized in Figure 6c (edge-type configuration). For further explanations, see the text.

Involvement of the Purkinje shift is suggested. Short wavelength color appears to be relatively bright under a dark condition. Decreasing illumination makes short wavelength color relatively bright. This might induce the luminance change-dependent motion illusion and show the color-dependent Fraser-Wilcox illusion.

錯視の種類	想定される輝度変調の発生部位
色依存のフレーザー・ウィルコックス錯視の暗い時の逆錯視	杆体
色依存のフレーザー・ウィルコックス錯視の明るい時の正錯視の急速相	杆体？
色依存のフレーザー・ウィルコックス錯視の明るい時の正錯視の緩徐相	ipRGC
最適化型フレーザー・ウィルコックス錯視　タイプI, II, III, IV	杆体 + ipRGC？
最適化型フレーザー・ウィルコックス錯視　ダークタイプ	ipRGC？
中心ドリフト錯視	錐体 + ipRGC？
矢印ドリフト錯視	錐体 + ipRGC？

続いて、輝度変調依存性の運動錯視が発生して動いて見える、と考える。

講演

「錯視と脳と視覚心理学」

北岡明佳氏（立命館大学文学部心理学専攻教授）

「ウェアラブルコンピュータ：健康、アート、パフォーマンス」

寺田努氏（神戸大学大学院工学研究科准教授）

「近未来ユビキタス住環境とＩＴの浸透」

平井重行（京都産業大学コンピュータ理工学部准教授）

パネルディスカッション

「脳と心とIT」

北岡氏、寺田氏、平井、田中宏喜（京都産業大学コンピュータ理工学部准教授）

コーディネーター

上田博唯（京都産業大学コンピュータ理工学部客員教授）

　脳の働きを計測する機器が目覚ましい発展を果たし、この数年で脳科学という研究分野がとても身近な存在になりました。

　本学でも脳科学に取り組む複数の研究室が活躍中です。また、生活の中のあらゆる場所にコンピュータが存在して日常生活をサポートしてくれるようになるユビキタスコンピューティング技術の普及も目前に迫っており、この分野でも本学の複数の研究室が精力的に取り組んでいます。

　このたび、これらの学術・技術分野と深い関係のある錯視の研究とウェアラブルコンピュータの研究で活躍中の二人の先生をお招きして、コンピュータ理工学部のシンポジウムを開催します。

　錯視は人間の脳の働きの不思議の一つであり、これを解明することで色々な脳の働きの謎を解く手がかりが得られると期待されています。

　ウェアラブルとは身につけるという意味ですが、どこにでもあるという意味のユビキタスと対をなす言葉で、今年大きな話題となったグーグルグラスに代表される眼鏡タイプのカメラやディスプレイなどと一緒に身につけるコンピュータなどを総称する言葉です。我々の生活をより豊かなものにする技術として期待されています。

　これらの分野の研究者のコラボレーションによって、どんな未来を切り開いて行くことができるのか、そういうことをそれぞれの思いを込めて語り合う場にしたいと考えています。

Type	dark to light	light to dark	Examples
IV new!

講演

「錯視と脳と視覚心理学」

「ウェアラブルコンピュータ：健康、アート、パフォーマンス」

「近未来ユビキタス住環境とＩＴの浸透」

パネルディスカッション

「脳と心とIT」

コーディネーター

コンピュータ理工学部シンポジウム開催