Search

Volume perception, that is, perception of a partially enclosed space filled with a medium, can be assessed not only from binocular viewing but also from motion. It was demonstrated that appearing and disappearing parts, which were generated by self-occlusion, play an essential role in volume perception from motion. In this study, we investigated volume perception in partially visible cylindrical and polyhedral objects occluded by proximal surfaces, and found that the ADPs bring volume perception not only in the cylindrical object but also in the polyhedral object, which appears to correspond to BURs for volume perception in binocular viewing.

A potential model to explain the phenomenon of illusory motion perception in still figures is proposed. By considering the isotropic spatial filtering process with time varying factor and visual reset, almost all of the features of this illusion can be simulated successfully as a physical system. It is considered that the system composed of an isotropic spatial filter and the visual reset is physiologically plausible and a similar mechanism is expected in the human visual system; the proposed model can provide new insights that can contribute to revealing the mechanism of the illusion and to elucidating the human visual system.

Volume perception, that is, perception of a partially enclosed space filled with a medium, can be assessed not only from binocular viewing but also from motion. We studied the volume perception of a cylindrical object in motion. The motion (rotation, translation, or rolling) of the cylindrical object was simulated with and without appearing and disappearing parts (ADPs). We found that volume perception could be assessed easily with ADPs but was difficult without ADPs. These experimental results indicate that ADPs are an essential factor for volume perception from motion, which is correspond to binocularly unpaired regions for volume perception in binocular viewing.

This study examined the perception of the rotating Kanizsa square by using a fixed-trial familiarization method. If the Kanizsa square is rotated across the pacmen, adult observers perceive not only a rotating illusory square, but also an illusory expansion/contraction motion of this square. The phenomenon is called a "rotational dynamic illusion". In experiments 1 and 2, we investigated whether infants perceived the rotational dynamic illusion, finding that 3-8-month-old infants perceived the rotational dynamic illusion as a simple rotation of the Kanizsa square. In experiment 3, we investigated whether infants perceived the rotational dynamic illusion as a rotation of the Kanizsa square or as a deformation of shape, finding that 3-4-month-old infants did perceive the rotational dynamic illusion as a rotation of the Kanizsa square. Our results show that while 3-8-month-old infants perceive the rotating Kanizsa square, however, it is difficult for the infants to extract expansion/contraction motion from the rotational dynamic illusion.

The visibility of an approaching target on the horizontal plane in peripheral vision with binocular viewing was studied. It was found that the perceptual performance for the target moving toward the middle point of the two eyes was remarkably worse; under this circumstance it has rather high performance in the absence of one eye’s target information with occlusion or falling on the blind spot. These facts imply that the conventional change disparity mechanism does not work in the peripheral visual field; while some simple combinations of the monocular information of two eyes, such as the sum of two eyes’ image motion with sign, can be used to detect an approaching motion in the periphery.

The Poggendorff illusion has been interpreted as a result of the physical interaction between a line element and an inducing element. We investigated the perceptual properties of the Poggendorff illusion for different depth relations between the two elements with binocular viewing in cases with and without physical interaction between them. The results show that this illusion occurred only when the depth of the line element was perceived as farther than or equal to that of the inducing element even without physical interaction between the two elements in which the gap between the line element and the inducing element was kept at 1.4 deg visual angle and the illusion was difficult to recognize in the individual view; the magnitude of the illusion under vertical conditions did not change with depth difference in the case without physical interaction, while it changed in the case with physical interaction. Then, we inferred that some veiled factors, which have not been considered before, exist in this illusion. Using the configuration without the physical interaction under horizontal conditions, we demonstrated that the perceived depth relation between two elements is one of the crucial factors for the Poggendorff illusion.

It has been known that the visual system can detect more than one disparity and/or motion direction at the same region in the image. These multiple (or transparent) surfaces can be perceived when, for example, we are looking scenes through a glass. However, many conventional models cannot deal with these multiple surfaces. The present paper investigates the neural encoding and decoding of multiple disparities with the binocular energy model, which is known as a biologically plausible model. Based on the analysis of the response of the energy model to multiple disparities, the present paper proposes a stereo model that can detect disparities of two overlapping surfaces.