一川 誠

The perceptual simultaneity range for two diotically presented tones increases with decreasing frequency separation of the two tones from approximately 0.5 Bark. As the present study of two frequency regions shows, this effect is not observed when the two tones are not presented to the same ear, i.e., presented dichotically. Since the increase in simultaneity is only observed when the tones are presented to the same ear, it is possible that it reflects the time-frequency uncertainty within a cochlear filter.

We examined the effects of emotional response, with different levels of valence and arousal, on the temporal resolution of visual processing by using photos of various facial expressions. As an index of the temporal resolution of visual processing, we measured the minimum lengths of the noticeable durations for desaturated photographs using the method of constant stimuli by switching colorful facial expression photographs to desaturated versions of the same photographs. Experiments 1 and 2 used facial photographs that evoke various degrees of arousal and valence. Those photographs were prepared not only in an upright orientation but also in an inverted orientation to reduce emotional response without changing the photographs’ image properties. Results showed that the minimum duration to notice monochrome photographs for anger, fear, and joy was shorter than that for a neutral face when viewing upright face photographs but not when viewing inverted face photographs. For Experiment 3, we used facial expression photographs to evoke various degrees of arousal. Results showed that the temporal resolution of visual processing increased with the degree of arousal. These results suggest that the arousal of emotional responses evoked by viewing facial expressions might increase the temporal resolution of visual processing.

<title>Abstract</title>This study proposes a system for estimating individual emotions based on collected indoor environment data for human participants. At the first step, we develop wireless sensor nodes, which collect indoor environment data regarding human perception, for monitoring working environments. The developed system collects indoor environment data obtained from the developed sensor nodes and the emotions data obtained from pulse and skin temperatures as big data. Then, the proposed system estimates individual emotions from collected indoor environment data. This study also investigates whether sensory data are effective for estimating individual emotions. Indoor environmental data obtained by developed sensors and emotions data obtained from vital data were logged over a period of 60 days. Emotions were estimated from indoor environmental data by machine learning method. The experimental results show that the proposed system achieves about 80% or more estimation correspondence by using multiple types of sensors, thereby demonstrating the effectiveness of the proposed system. Our obtained result that emotions can be determined with high accuracy from environmental data is a useful finding for future research approaches.

This paper proposes and develops wireless sensor nodes to monitor working environments and human emotions estimation. The proposed system collects indoor environment data, which concern human perception, through Wireless Sensor Network. Human emotions are estimated based on the Machine Learning techniques and collected sensor data. In other words, the proposed system estimates the human emotions without image data form camera sensor or vital data from wearable sensors. Experimental results show that the proposed system achieves over 80% estimation accuracy by using multiple kinds of sensors. It is seen from the experimental results that the developed sensors are helpful to estimate human emotions.

It is well known that the perceived duration for a given time period decreases with the reduction of the number of perceived events. We examined whether target detection failures in viewing Rapid Serial Visual Presentation (RSVP) sequence, caused by attentional blink, affect this reduction of perceived duration. In two experiments, trials consisted of displays of two series of RSVP sequences; in the first sequence (the comparison), two, one, or no numerals were presented as targets embedded within the string of letters, while in the second sequence (the standard), only alphabetic letters were presented. In each trial, participants judged whether the duration of the comparison is perceived as longer than that of the standard (Experiment 1), or whether the number of frames in the comparison is perceived as more than that in the standard (Experiment 2). Results showed that perceived duration was inflated with target detection, but not with the increment of presented frames although number of perceived frames was inflated with both target detection and increment of presented frames. These results suggest that perceived duration in viewing RSVP sequences is determined by the cognitive load necessary to accomplish target detection rather than by the number of perceived frames.

When two tones start with a small onset asynchrony, one might perceive them as starting simultaneously. The range of this perceptual synchrony is defined as a perceptual simultaneity range (PSR), within which two tones are perceived as simultaneous. Our earlier study found V-shaped behavior of the PSR as a function of frequency separation (Δ f) for two tones. For this study, we investigated the PSR as a function of frequency separation (Δ f) and frequency range (F1). The PSR was measured using the simultaneity judgment task. Results demonstrated that the PSR decreases steeply and then increases gradually along the Δ f axis. Its breakpoint appeared at circa 0.5 critical bandwidth (CB), irrespective of F1. The PSR-Δ f curves for different F1 were almost coincident for Δ f ≲ 0.5 CB. The coincident decrease of the PSR for small Δ f supports the notion that the cochlear interference affects the perception of simultaneity.

In order to examine how the voluntary inspiration-expiration circle affect the effects of visual attention on target detection task, we conducted two experiment in which observers attended to the target location or non target location in terms of the cost-benefit method (Posner, 1980). In the experiments, observers conducted target detection task during or after inspiration, or expiration. In the first experiment, a visual cue was presented to attract endogenous visual attention, or exogenous visual attention, while in the second experiment, visual cues were presented to attract both endogenous and exogenous attention. We found advantages of inspiration with the exogenous attention task, but advantages of expiration with the endogenous attention task. We discussed the implications of these results for appropriate respiratory control in the competitive sports.

豪雨などの自然災害の際，避難指示が出されても，なかなか住民の避難行動が喚起されないという問題が指摘されている．本論では，様々な産業事故の背景に認知的バイアスがあったことを指摘した上で，住民の避難行動の忌避の基礎にも様々な認知的バイアスがあることを指摘した．また，避難行動における時間管理に関する認知的問題についても解説した．さらに，避難行動を喚起するために認知的バイアスを利用することの有効性について解説した．

When observers move the head backwards and forwards while fixating on the center of the concentric circles that consist of oblique lines, they see illusory rotation of those circles. If several dots are superimposed on the proximity to the inner concentric circles, observers see the illusory rotation not only for the circles but also for the superimposed dots. This illusory rotation of the dots is based on motion capture. In this study, in order to understand the basis of the motion capture, we examined how motion signal with different directions (rotation, expansion/contraction, and horizontal translation) in terms of motion on a display, as well as illusory motion signal from the oblique components, affects the motion capture. If the stimulus presented rotation with expansion/contraction, or rotation with horizontal translation for the entire stimulus, then observers tended to perceive motion capture for the superimposed dots. However, if the stimulus presented only rotation of the circles, then observers tended to perceive induced motion for the superimposed dots. These results suggest that the existences of the common fate factor for the entire stimulus determine the means of allocating and integrating the motion signal in each element in the stimulus to generate motion capture.

Our earlier study demonstrated that the subjective sharpness of blurred images is improved by superimposing granular noise on it. We proposed that we have memory of textures of certain familiar objects encountered in daily life, similar to memory color. As de- scribed herein, for ve objects, we used sample images of six kinds: the original image, a white-noise-added original image, a 1/ f-noise-added original image, a blurred original image, a white-noise-added blurred image, and a 1/f-noise-added blurred image. First, observers were asked to recall an object’s texture without seeing the real object and to sort the images in descending order, starting with the one closest to the recalled texture. While viewing the actual object, observers were asked to rearrange the images in descending order, starting with the one closest to the actual texture. Finally, observers were asked to rearrange the images in descend- ing order of subjective sharpness. Correlation analysis, partial analysis, and path analysis were conducted for this reported ordering. Correlation was found between the memory texture and subjective sharpness. Results demonstrate that subjective sharpness im- proved when the texture of the objects in images came to approximate the remembered texture.

This paper provides a phenomenological quantitative function of the perceptual simultaneity range (PSR) in terms of the frequency separation and a possible explanation. The PSR for two pure tones was measured with the frequency separation between the tones from 0.07 to 4.09 octaves with the lower frequency fixed at 200 Hz. In this study, listeners judged the simultaneity of the tones using the perceptual synchrony-asynchrony cue while the possible use of the perceptual fusion-separation cue ("oneness" or "twoness") was eliminated. Results show that the PSR plotted against the frequency separation can be fitted to two segmented linear regression lines, one decreasing for small frequency separation and the other increasing for large frequency separation. These regression lines intersect around the critical bandwidth. Results also show no effects of the frequency separation on the singular interval or points, such as tonal consonance, musical consonance, and harmonic relations. These results suggest that the perception of simultaneity is mainly determined by the peripheral representation of the tone distance. We propose a possible explanation for the behavior of the PSR for small frequency separation by considering the mechanics of basilar membrane motion. However, the explanation for the behavior for large frequency separation is still unclear.

時間に関する知覚過程は，一義的な解のない不良設定問題を解決する過程とみなすことができる．すなわち，時間知覚は，時間進行のペースや事象間の間隔についての確かな情報がないのに，0 次元もしくは０.5 次元的に得られる諸事象についての知覚情報を一次元的な進行する時間軸上に位置付ける過程と見なすことができる．普段の時間知覚において，何らかの巧妙な方略を用いることによって知覚系はこの不良設定問題に一応の解を与えていると考えられる．本研究では，知覚系がこの不良設定問題解決に用いている方略を理解するために，時間に関する錯視，錯覚の特性を整理した．その上で，進行する時間軸上への諸事象の位置付けという不良設定問題解決のため，知覚系が，処理促進による遅延の短縮や，顕著な情報による引き込み的処理などの方略を用いていることを示した．

This study investigated the range of perceptual simultaneity, within which listeners perceive two asynchronous tones as simultaneous, as a function of frequency separation and fundamental frequency of the tones. In the experiment used for this study, two pure tones were presented diotically with various asynchrony (-100 ms to 100 ms) and frequency separation (0.03-2.89 octaves). The listener's task was to judge whether these two pure tones were perceptually simultaneous or not. The resultant function of perceptual simultaneity range against frequency separation with fundamental frequency of 800 Hz was compared to that of 200 Hz. Both functions show V-shaped curvature: the perceptual simultaneity range decreased steeply and then increased gradually with increased frequency separation. The breakpoint of the V-shaped functions appeared at around the critical bandwidth. This breakpoint was predicted best by the Critical Bandwidth (CB) scale, rather than by Equivalent Rectangular Bandwidth (ERB) or octave scales. These findings support the notion that the mechanics of cochlear basilar membrane motion affect the perception of simultaneity in close frequency separation.

Present study investigated the range of perceptual simultaneity, within which listeners perceive two asynchronous tones as simultaneous, as a function of frequency separation and fundamental frequency of the tones. This function was obtained with frequency separations ranging from 0.03 to 5.00 octaves, and fundamental frequencies ranging from 100 to 800 Hz. Listener’s task was to judge whether the two asynchronous pure tones were perceptually simultaneous or not. Results showed a V-shaped function for the perceptual simultaneity range against the frequency separation regardless of fundamental frequency. The perceptual simultaneity range steeply decreased and then gradually increased with the increment of frequency separation. The breakpoint of the V-shaped function was appeared at around the critical bandwidth. This breakpoint was best predicted by CB (Critical Bandwidth) scale, rather than by ERB (Equivalent Rectangular Bandwidth) or octave scales. These findings supported the notion (Okazaki &amp; Ichikawa, 2015, Proc. Acoust. Soc. Jpn.) that the perception of simultaneity involves two different processes. These two processes would be explained respectively by the mechanics of cochlear basilar membrane motion, and by phase locking of the auditory nerve fibers.

We examined how impression (such as safety, pleasantness, and impact), as well as emotional arousal and valence, evoked by viewing a picture affects temporal resolution of visual processing and perceived picture duration. In the first experiment as an index of temporal resolution of visual processing, we measured the noticeable duration of a monochrome picture after presenting a color picture. In the second experiment, we measured the duration of the picture presentation, which was equivalent to the duration of the presentation of a gray rectangle that should not evoke specifically safe or pleasant impressions. We found that the minimum duration in which an observer could notice a monochrome image in viewing a dangerous picture was shorter than that in viewing safe pictures. We also found that observers overestimated the duration of the picture presentation in viewing dangerous pictures. However, there was no significant correlation between the results of the two experiments. These results suggest that the basis for improvement of the temporal resolution in visual processing differs from that for the elongation of the perceived duration.

This study examined how the contents and timing of a visual stimulus affect the identification of mixed sounds recorded in a daily life environment. For experiments, we presented four environment sounds as auditory stimuli for 5 s along with a picture or a written word as a visual stimulus that might or might not denote the source of one of the four sounds. Three conditions of temporal relations between the visual stimuli and sounds were used. The visual stimulus was presented either: (a) for 5 s simultaneously with the sound (b) for 5 s, 1 s before the sound (SOA between the audio and visual stimuli was 6 s) or (c) for 33 ms, 1 s before the sound (SOA was 1033 ms). Participants reported all identifiable sounds for those audio–visual stimuli. To characterize the effects of visual stimuli on sound identification, the following were used: the identification rates of sounds for which the visual stimulus denoted its sound source, the rates of other sounds for which the visual stimulus did not denote the sound source, and the frequency of false hearing of a sound that was not presented for each sound set. Results of the four experiments demonstrated that a picture or a written word promoted identification of the sound when it was related to the sound, particularly when the visual stimulus was presented for 5 s simultaneously with the sounds. However, a visual stimulus preceding the sounds had a benefit only for the picture, not for the written word. Furthermore, presentation with a picture denoting a sound simultaneously with the sound reduced the frequency of false hearing. These results suggest three ways that presenting a visual stimulus affects identification of the auditory stimulus. First, activation of the visual representation extracted directly from the picture promotes identification of the denoted sound and suppresses the processing of sounds for which the visual stimulus did not denote the sound source. Second, effects based on processing of the conceptual information promote identification of the denoted sound and suppress the processing of sounds for which the visual stimulus did not denote the sound source. Third, processing of the concurrent visual representation suppresses false hearing.

In order to examine how the voluntary smooth pursuit eye movement and other factors, such as retinal slip, which is caused by stimulus movement, affect the illusory snake rotation (Kitaoka, 2005), we conduced three experiments in which observer voluntarily pursuit a moving fixation point. Results of the experiments showed that the smooth pursuit, which is larger than 5.0deg, facilitates the illusory rotation. However, because the afterimage could generate the substantial illusory rotation, the eye movement, or retinal slip which is caused by stimulus or eye movement, is not the necessary to obtain the illusory rotation. Based upon the results of the present study, we proposed an observation method that would enable to obtain a vivid illusory rotation even for the observer who had difficulty to obtain the illusory rotation in viewing the category of the Fraser–Wilcox illusion with the normal observation.

We examined how changes in participants’ heart rate affect their estimation of time when listening to music. We manipulated participants’ heart rate using a cycling task on an exercise bike and by varying the tempo of music. The heart rates of 48 participants were measured before and after the pedaling task on the exercise bike. One week later, they listened to the music and estimated the temporal duration (60 seconds) under the non-manipulated condition (without exercise) and heart rate manipulated condition (with exercise). The results showed that the duration of the music (60 seconds) was underestimated after light exercise and overestimated after strenuous exercise. These results suggest that the acceleration of the internal time mechanism due to an increase in the heart rate affects the perceived duration of time with relation to music.

Consistent exposure to a temporal lag between observers&#039; voluntary action and its visual feedback induced recalibration of temporal order perception between a motor action and a visual stimulus. It remains unclear what kinds of processing underlie this motor–visual temporal recalibration. This study examined the necessity of awareness of a temporal lag between a motor action and its visual feedback for motor–visual temporal recalibration. In Experiment 1, we allocated observers to either the multiple-step or single-step lag conditions. In the multiple-step lag condition, we first inserted a small temporal lag and subsequently increased it with progress of the adaptation period, to make observers unaware of the temporal lag during the adaptation period. In the single-step lag condition, we instructed observers about the temporal lag before adaptation, and inserted a substantial temporal lag from the beginning of the adaptation period to ensure that they were aware of the temporal lag. We found significant recalibration only in the single-step lag condition. In Experiment 2, we exposed all observers to a substantial temporal lag from the beginning of adaptation period with no instruction about insertion of the temporal lag. We asked observers at the end of the experiment whether they were aware of the temporal lag. We found significant recalibration for only observers who were aware of the lag. These results suggest that awareness of the temporal lag plays a crucial role in motor–visual temporal recalibration.

本研究では目標物検出の反応時間に聴覚刺激のテンポが及ぼす影響について検討した。聴覚刺激のテンポと視覚刺激の偏心度を操作し，3つの実験を行った。聴覚刺激として，実験1ではテンポが12.5Hzと25Hz，50Hzの単音，実験2では心拍数を基準とした80bpmと60%速いテンポ，60%遅いテンポの単音（実験2-1）ないしBGM（実験2-2）をそれぞれ提示した。視覚刺激の偏心度は, 4度，8度，12度，16度，20度であった。参加者は聴覚刺激を聴取後にモニター上のプレイスホルダーのいずれかにドットの提示が確認できたら即座にキーを押すことが求められた。実験2-2では各テンポのBGMを実験中常に与え続けた。実験の結果，テンポの速い聴覚刺激が視覚刺激への反応を速めることが示された。しかし，聴覚刺激のテンポが速いほど反応が速められるわけではなく，耳障りといった嫌悪感を喚起させる音は，反応を速めなかった。

This study investigated the basis of a right-side dominance in aesthetic arrangement. In experiment 1, in order to examine the effect of attended position in pictures on aesthetic arrangement, we manipulated the positions of the fixation points, which attract observer&#039;s attention, and centroids of triangle arrangement for three objects. Participants rated preference, balance, beauty and harmony by the use of seven points scale for each of the pictures. We found that participants evaluated highly aesthetic in viewing the pictures whose arrangement centroids were near to the fixated position. In experiment 2, in order to examine the effect of participant&#039;s dominant hand on aesthetic arrangement we presented the objects which the participants are willing to manually manipulate, or the object which they should avoid to manually touch for right-handed or left-handed participants. We found that right-handed participants evaluated highly aesthetic in viewing the pictures whose arrangement centroid was at right side, but left-handed participant did not.

As in the Pinna illusion, when an observer moves their head backwards and forwards while fixating on the center of concentric circles that consist of oblique lines, the observer sees illusory rotation of those circles. When several dots are superimposed on the concentric circles, an observer sees the illusory rotation not only for the circles, but also for those dots (Ichikawa, Masakura, & Munechika, 2006, Perception, 35, 933-946). This illusory rotation of the dots, which have no means of generating illusory motion themselves, is based on motion capture. We examined how the number of dots affects the illusory rotation for such circles and superimposed dots. Results showed that the illusory rotation for the inner circle was most salient when the superimposed dots were extremely numerous or few, although the illusory motion for the dots increased with the increment of the dots. These results suggest that motion capture depends upon a locally obtained motion signal from the oblique lines, and upon the accumulation of the motion signal within the groups of superimposed dots.

This study investigated how the several factors of BGM (Background music) affected the time estimation . We composed 28 original music tunes with different tempo and notes. Twenty undergraduates estimated one minute by the use of the method of production while listening to a BGM. Results showed that participants underestimated the duration while listening to a tune with a slow tempo, whereas they overestimated while listening to the tunes with fast tempo. The participants overestimated the duration with the increment of the number of the notes per unit time and variety of a note. In addition, the music experiences influenced the auditory time estimation.

Four experiments investigated how observers' consciousness about their control of stimulus change affects the visual perception associated with the illusory flash-lag effect. In previous study (Ichikawa and Masakura, 2006), we found that the flash-lag effect in motion is reduced if observers were conscious that they were controlling stimulus movements by the use of computer mouse, even if the stimulus moved automatically, independently of observer's mouse control. In the other study (Ichikawa and Masakura, 2010a), we found that the consistent directional relationship between the observer's mouse control and stimulus movement, which is learned in our everyday computer use, is important for the reduction of the flash-lag effect in active observation. In the present study, we examined whether the reduction of the flash-lag effect in active observation requires the observers' consciousness about their control of stimulus change, and consistency in coupling mouse movement direction and stimulus change across trials in experiments. We used the flash-lag effect in luminance change because there is no intrinsic relationship between observer's mouse control and luminance change in our everyday computer use. We compared the illusory flash-lag effects for automatic change of the luminance with luminance change that was controlled by the observers' active manipulation of a computer mouse. Because the flash occurs randomly in time, observers could not anticipate when the flash was presented. Results suggest that the not only observer's consciousness of controlling the stimulus, but also consistency in coupling mouse movement direction with stimulus change, are required for the reduction of the flash-lag effect in active observation. The basis of the reduction of the flash-lag effect in active observation is discussed.

本研究は，複雑かつ生物的な運動ほど注視され，刺激への好意度を上昇させるかを検討した．実験1Aは対象の運動の方向変化回数（1回，3回，7回）と変化タイミング（一定，ランダム），実験1Bでは実験1Aの要因に対象の加速度（加速，減速，加減速混合）を加えて，実験2（実験2Aは実験1と同様の自由観察であり，実験2Bは注視点を注視させた統制実験であった）ではアイトラッカーを用いて実際に参加者の眼球運動を観察し，それらが参加者の刺激評価に及ぼす影響を調べた．参加者には，運動する黒縁の円を8秒間呈示したあと，円の動きについて6尺度（面白さ，好意度，複雑性，生物性，関心度，印象度）を7段階で評定するよう求めた．実験の結果，物体運動の複雑性・生物性が能動的な注視を喚起させ，刺激への評価を上昇させた．また，刺激への視覚探査が見られ，対象物体の加速度により追い方や視線停滞数の違いが見られた．

This chapter presents an image-processing algorithm for edge detection and orientation selection with discretely coupled nonlinear elements. The algorithm utilizes the nonlinear characteristic of the FitzHugh-Nagumo model and arranges the elements on an image grid system. The model is described with a pair of ordinary differential equations with activator and inhibitor variables, and exhibits mono-stable excitability. It was previously found that a grid system consisting of mono-stable nonlinear elements self-organizes pulses at crossing points between an initial activator distribution and a threshold level. In particular, the imposition of strong inhibitory coupling on the grid system causes stationary pulses at the crossing points. The algorithm presented here focuses on the phenomenon in which the grid system self-organizes stationary pulses at the crossing points. In addition, the algorithm introduces anisotropic coupling strength into the grid system the coupling strength is decided according to the difference between the gradient direction of the inhibitor distribution and the specific orientation. An experimental section demonstrates the results of edge detection and orientation selection for artificial and real images. © 2013 Springer-Verlag Berlin Heidelberg.

This chapter presents an image-processing algorithm for edge detection and orientation selection with discretely coupled nonlinear elements. The algorithm utilizes the nonlinear characteristic of the FitzHugh-Nagumo model and arranges the elements on an image grid system. Themodel is described with a pair of ordinary differential equations with activator and inhibitor variables, and exhibits mono-stable excitability. It was previously found that a grid system consisting of mono-stable nonlinear elements self-organizes pulses at crossing points between an initial activator distribution and a threshold level. In particular, the imposition of strong inhibitory coupling on the grid system causes stationary pulses at the crossing points. The algorithm presented here focuses on the phenomenon in which the grid system self-organizes stationary pulses at the crossing points. In addition, the algorithm introduces anisotropic coupling strength into the grid system the coupling strength is decided according to the difference between the gradient direction of the inhibitor distribution and the specific orientation. An experimental section demonstrates the results of edge detection and orientation selection for artificial and real images. © Springer-Verlag Berlin Heidelberg 2013.

In many psychophysical studies of visual processing, observers passively viewed the stimuli, without any active involvement with stimulus change. Observerʼs active involvement with stimulihasbeenneglectedinvisualpsychophysicsforlongtime. Thisstudyinvestigateshowthe observerʼs active manipulation of stimuli affects the visual processing. In particular, we conducted several experiments to examine the effects of active observation on the illusory flash- lag effect. In those experiments, observers actively controlled the visual stimulus on display by the use of computer mouse. If observer was familiar with the directional relationship between themousemovementandstimulusmovement,theflash-lageffectwassignificantlyreduced. We summarize the conditions of active observation under which the flash-lag effect is reduced, and several other effects of active observation on visual illusions. We are proposing that, in active observation, the learning of a consistent directional relationship between a proprioceptive signal of hand movements and visual signal of stimulus movements is necessary for facilitation of the visual processing, and that proprioceptive information disambiguates the visual information in forming the visual representation.

We examined how the size of binocular disparity, which determines the apparent depth magnitude, affects the impressions in different dimensions in viewing nonrepresentational stereograms and representational stereoscopic pictures by the use of semantic differential method with the scales that are related to the basic dimensions of impression: evaluation, activity, potency, and reality. In viewing nonrepresentational stereograms, which presented a binocular disparity ranging from 0 to approximately 70 min of arc between the central line, or a rectangle with a peripheral frame, the ratings for the scales for the evaluation impression were the highest at approximately 1020 arc min of disparity, while the ratings for the activity impression increased with the size of the disparity. In viewing the representational and nonrepresentational stereograms, the ratings for the scales, which are related to the evaluation, activity, and reality factors, increased with the size of the disparity if the disparity specified multiple depth layers. These results indicate that the effects of binocular disparity in viewing a stereoscopic picture depend on the disparity distribution and disparity size rather than the representationality of the stereogram.

Temporal order judgment (TOM between the voluntary motor action and its perceptual feedback is important in distinguishing between a sensory feedback which is caused by observer's own action and other stimulus, which are irrelevant to that action. Prolonged exposure to fixed temporal lag between motor action and visual feedback recalibrates motor-visual temporal relationship, and consequently shifts the point of subjective simultaneity (PSS). Previous studies on the audio-visual temporal recalibration without voluntary action revealed that the low level processing is involved. However, it is not clear how the low and high level processings affect the recalibration to constant temporal lag between voluntary action and visual feedback. This study examined retinotopic specificity of the motor-visual temporal recalibration. During the adaptation phase, observers repeatedly pressed a key, and visual stimulus was presented in left or right visual field with a fixed temporal lag (0 or 200 ms). In the test phase, observers performed a TOJ for observer's voluntary keypress and test stimulus, which was presented in the same as or opposite to the visual field in which the stimulus was presented in the adaptation phase. We found that the PSS was shifted toward the exposed lag in both visual fields. These results suggest that the low visual processing, which is retinotopically specific, has minor contribution to the motor-visual temporal lag adaptation, and that the adaptation to shift the PSS mainly depends upon the high level processing such as attention to specific properties of the stimulus.

This paper proposes a stereo algorithm utilising a reaction-diffusion system defined in a three-dimensional domain. A previous reaction-diffusion stereo algorithm provides a stereo disparity map by utilising multi-layered reaction-diffusion systems defined in a two-dimensional domain. The previous algorithm assumes that three-dimensional structures of scenes consist of unslanted planar surfaces and approximately describes any slanted or curved surfaces with piecewise unslanted planar surfaces. However, in real scenes there are highly slanted or curved surfaces, which violate the assumption of the previous algorithm and cause inaccurate results of disparity distribution, in particular, with respect to subpixel accuracy. The reaction-diffusion system consists of reaction-diffusion equations, which are described with partial-differential equations and solved with a numerical computation technique such as a finite difference method. Thus, we revise the reaction-diffusion stereo algorithm by utilising a reaction-diffusion system defined in a three-dimensional domain consisting of the two-dimensional domain plus a disparity domain. Discretisation of the disparity domain brings subpixel accuracy and helps the algorithm to detect accurate disparity for slanted or curved surfaces. In addition, this paper proposes a two-stage algorithm for fill-in of disparity undefined areas caused by little image feature. Finally, this paper demonstrates performance of the proposed algorithm for slanted or curved surfaces with the Middlebury stereo vision data-sets. © 2012 ACM.

We examined how the denotative congruency in audio-visual stimuli affects the pleasant and restful impressions of the stimuli. In Experiment 1, in which we combined a single sound and a single motion picture, we found that the impressions of the audio-visual stimuli would be determined in terms of averaging the impressions obtained from each of the audio and visual stimuli. In Experiment 2, in which we combined two sounds and a single motion picture, we found that the pleasant and restful impressions positively shifted when one of the sounds was combined with the denotatively congruent motion picture, even if the unpleasant and unrestful sound was combined with an unpleasant and unrestful motion picture. These results suggested that the denotative congruency between the audio and visual stimuli would improve the pleasant and restful impressions. We are proposing that the stimulus complexity, which would be reduced by the denotative congruency between the audio and visual stimuli, underlies the positive shift of the pleasant and restful impressions in observing the stimuli.

We examined the relation between the perception and impression formation of temporal congruency in audio-visual stimuli. The luminance of the visual stimulus changed repeatedly with a constant temporal frequency. The audio stimulus was periodic drum sounds. In the phase-asynchrony condition, the audio stimulus was varied in its phase. In the frequency-asynchrony condition, it was varied in its temporal frequency. Nine conditions were used for asynchrony between the audio and visual stimuli (0, +/- 48, +/- 96, +/- 192, +/- 384 ms). The results showed that the participants had an impression of the temporal congruency even if they perceived asynchronicity in the audio-visual stimulus. This result was particularly true when the audio-visual stimulus was slow. Both processing that underlies impression formation and processing that underlies the perceptual judgment consider not only the time lag between the audio and the visual stimuli, but also the temporal frequency of the stimuli. These results suggest that the rule underlying the impression formation of the temporal congruency for audio-visual stimuli differs from that underlying the perceptual temporal order judgment for audio-visual stimuli.

This paper presents a reaction-diffusion stereo algorithm with anisotropic diffusion. The reaction-diffusion stereo algorithm detects the stereo disparity, by finding a one-to-one stereo correspondence between the left and right images. There is often ambiguity in finding stereo correspondences because of a lack of texture or similar brightness patterns in objects. In addition, in occluded areas, there is no information by which to find stereo correspondence. Thus, it is necessary to fill in undetected areas of stereo disparity from neighbouring detected areas on a stereo disparity map according to the two constraints of uniqueness and continuity. The reaction-diffusion stereo algorithm realises the continuity constraint with the two different diffusion processes of activation and inhibition. Motivated by psychological evidence from actual human stereo depth perception, this paper proposes the imposition of anisotropic inhibitory diffusion on the algorithm. We apply the proposed anisotropic reaction-diffusion algorithm to several pairs of stereo images and evaluate its performance in comparison to the original reaction-diffusion stereo algorithm. Results of the evaluations show that the addition of anisotropic inhibitory diffusion is partially effective in depth discontinuity areas. © 2011 IEEE.

This paper presents a computer algorithm of detecting edges from a grey scale image with FitzHugh-Nagumo type excitable elements discretely spaced at image grid points. A previous edge detection algorithm utilising the elements is not applicable to darker intensity areas surrounded by brighter ones the algorithm fails in detecting edges in the areas. In order to solve the problem in detecting edges in relatively dark areas, we proposed to utilise an intensity inverted image as well as its original one. The proposed algorithm firstly provides a tentative edge map from the original image, and simultaneously provides an additional tentative edge map from the inverted image. Then, the algorithm provides a final edge map by merging the two edge maps. We quantitatively confirm performance of the proposed algorithm, in comparison with that of the previous one and that of the Canny algorithm for an artificial grey scale image not having noise. We furthermore confirm robustness and convergence of the proposed algorithm for a noisy image and real ones. These results shows that the performance of the proposed algorithm is much higher than the previous one and is comparable with the Canny algorithm for a noise-less image, and the proposed algorithm converges for all of the images. However, the proposed algorithm is vulnerable for additive noise, in comparison with the Canny algorithm and the anisotropic diffusion algorithm. © 2011 IEEE.

We report a new angle illusion observed when viewing a real scene involving a straight road. The scene portrays two white lines which outline a traffic lane on a road and converge to a vanishing point. In experiment 1, observers estimated the angle created by these converging lines in this scene or in its image projected onto a screen. Results showed strong underestimation of the angle, ie over 50% for observations of both the real scene and its projected image. Experiment 2 assessed how depth cues in projected images influence the angle illusion. Results showed that this angle illusion disappeared when scene information surrounding convergent lines was removed. In addition, the illusion was attenuated with projection of an inverted scene image. These findings are interpreted in terms of a misadoption of depth information in the processing of angle perception in a flat image; in turn, this induces a massive angle illusion.

In the present study, we investigated how observers&apos; control of stimulus change affects temporal and spatial aspects of visual perception. We compared the illusory flash-lag effects for automatic movement of the stimulus with stimulus movement that was controlled by the observers&apos; active manipulation of a computer mouse (Experiments 1, 2, and 5), a keyboard (Experiment 3), or a trackball (Experiment 4). We found that the flash-lag effect was significantly reduced when the observer was familiar with the directional relationship between the mouse movement and stimulus movement on a front parallel display (Experiments 1 and 2) and that, although the unfamiliar directional relationship between the mouse movement and stimulus movement increased the flash-lag effect at the beginning of the experimental session, the repetitive observation with the same unfamiliar directional relationship reduced the flash-lag effect (Experiment 5). We found no consistent reduction of the flash-lag effect with the use of a keyboard or a trackball (Experiments 3 and 4). These results suggest that the learning of a specific directional relationship between a proprioceptive signal of hand movements and a visual signal of stimulus movements is necessary for the reduction of the flash-lag effect.

平面図形に対する配色による立体感の効果について調べる実験を行なった.刺激として,白色背景上の3個の平行四辺形それぞれに異なる色相,明度,彩度で彩色されたものを組み合せた正六角形を用いた.20名の観察者に対して,正六角形の立体感を調べるために一対比較法を用いた.次の4点の結果が得られた.1)有彩色では,彩度よりも明度の影響が大きい.2)上位置の色面の明度が高いと立体感が強い.3)無彩色では,中程度の明度差において立体感が強い.4)対照色相配色は一貫した立体感や平面の印象が生じない傾向がある.これらの結果から,平面図形に対する配色により立体感を調節することができる可能性が示唆された.