VECTION INDUCED BY ILLUSORY MINIATURIZATION OF MOVING PICTURE

The effects of image miniaturization on visually induced self-motion perception (vection) were examined in a psychophysical experiment in which 11 observers participated. The original motion picture stimulus was filmed from a camera mounted on the front of a moving train. This kind of motion stimulus can be considered equivalent to retinal flow that we daily experience under natural visual environment, and termed as "real world stimulus". Saturation enhancementand defocused blur were applied to this original movie, as two types of miniaturization transformations. The results of psychophysical experiment revealed that the miniaturized movies can induce self-motion perception as strong as the original stimulus, although naturalness of the image experienced under the miniaturized conditions were significantly detracted. Impacts of using a real world stimulus as a future vection inducer were discussed base on the results

Designing Virtual Reality Headsets to Prevent Myopia

Virtual reality (VR) headsets are currently being designed and developed for consumer use. Simultaneously, the rate of myopic development is increasing around the world. Little is known about the connection between the proximity viewing in VR headsets and myopic development. The past three decades of research have indicated a probable relationship between near-work activities and the development of myopia. Based on the current research, VR headsets do not appear to induce a strong myopiagenic stimulus on axial elongation. This paper offers a potential explanation and proposes a set of design recommendations for designing future VR headsets that prevent myopia

Visual discomfort and depth-of-field

Visual discomfort has been reported for certain visual stimuli and under particular viewing conditions, such as stereoscopic viewing. In stereoscopic viewing, visual discomfort can be caused by a conflict between accommodation and convergence cues that may specify different distances in depth. Earlier research has shown that depth-of-field, which is the distance range in depth in the scene that is perceived to be sharp, influences both the perception of egocentric distance to the focal plane, and the distance range in depth between objects in the scene. Because depth-of-field may also be in conflict with convergence and the accommodative state of the eyes, we raised the question of whether depth-of-field affects discomfort when viewing stereoscopic photographs. The first experiment assessed whether discomfort increases when depth-of-field is in conflict with coherent accommodation-convergence cues to distance in depth. The second experiment assessed whether depth-of-field influences discomfort from a pre-existing accommodation-convergence conflict. Results showed no effect of depth-of-field on visual discomfort. These results suggest therefore that depth-of-field can be used as a cue to depth without inducing discomfort in the viewer, even when cue conflicts are large. © 2013 L O'Hare, T Zhang, H T Nefs, P B Hibbard

Evaluation of depth of field for depth perception in DVR

pre-printIn this paper we present a user study on the use of Depth of Field for depth perception in Direct Volume Rendering. Direct Volume Rendering with Phong shading and perspective projection is used as the baseline. Depth of Field is then added to see its impact on the correct perception of ordinal depth. Accuracy and response time are used as the metrics to evaluate the usefulness of Depth of Field. The onsite user study has two parts: static and dynamic. Eye tracking is used to monitor the gaze of the subjects. From our results we see that though Depth of Field does not act as a proper depth cue in all conditions, it can be used to reinforce the perception of which feature is in front of the other. The best results (high accuracy & fast response time) for correct perception of ordinal depth occurs when the front feature (out of the two features users were to choose from) is in focus and perspective projection is used

The Southampton-York Natural Scenes (SYNS) dataset: statistics of surface attitude

Recovering 3D scenes from 2D images is an under-constrained task; optimal estimation depends upon knowledge of the underlying scene statistics. Here we introduce the Southampton-York Natural Scenes dataset (SYNS: https://syns.soton.ac.uk), which provides comprehensive scene statistics useful for understanding biological vision and for improving machine vision systems. In order to capture the diversity of environments that humans encounter, scenes were surveyed at random locations within 25 indoor and outdoor categories. Each survey includes (i) spherical LiDAR range data (ii) high-dynamic range spherical imagery and (iii) a panorama of stereo image pairs. We envisage many uses for the dataset and present one example: an analysis of surface attitude statistics, conditioned on scene category and viewing elevation. Surface normals were estimated using a novel adaptive scale selection algorithm. Across categories, surface attitude below the horizon is dominated by the ground plane (0° tilt). Near the horizon, probability density is elevated at 90°/270° tilt due to vertical surfaces (trees, walls). Above the horizon, probability density is elevated near 0° slant due to overhead structure such as ceilings and leaf canopies. These structural regularities represent potentially useful prior assumptions for human and machine observers, and may predict human biases in perceived surface attitude

Placement de caméras et ajustement automatique des paramètres de stéréoscopie

La visualisation 3D stéréoscopique connaît un regain d'intérêt avec l'apparition sur le marché grand public de dispositifs de visualisation à des coûts très abordables. Cependant, ces écrans engendrent une fatigue visuelle inhérente aux systèmes d'affichage stéréoscopique essentiellement en raison de la divergence entre les stimuli d'accommodation et de convergence. Ce problème a fait l'objet de nombreuses recherches mais ces résultats sont encore peu exploités dans le monde de l'infographie 3D alors que les paramètres de prise de vue sont beaucoup plus facilement contrôlables que dans le cas d'une acquisition vidéo. Le travail réalisé s'appuie sur le contrôle différencié de la disparité, pour proposer une méthode de compression progressive de l'espace virtuel, de manière à obtenir le meilleur compromis possible entre confort et qualité de visualisation

(Disparity-Driven) Accommodation Response Contributes to Perceived Depth

When looking at objects at various distances in the physical space, the accommodation and vergence systems adjust their parameters to provide a single and clear vision of the world. Subtended muscle activity provides oculomotor cues that can contribute to the perception of depth and distance. While several studies have outlined the role of vergence in distance perception, little is known about the contribution of its concommitant accommodation component. It is possible to unravel the role of each of these physiological systems by placing observers in a situation where there is a conflict between accommodation and vergence distances. We thus sought to determine the contribution of each response system to perceived depth by simultaneously measuring vergence and accommodation while participants judged the depth of 3D stimuli. The distance conflict decreased depth constancy for stimulus displayed with negative disparity steps (divergence). Although vergence was unaffected by the stimulus distance, accommodation responses were significantly reduced when the stimulus was displayed with negative disparities. Our results show that biases in perceived depth follow undershoots in the disparity-driven accommodation response. These findings suggest that accommodation responses (i.e., from oculomotor information) can contribute to perceived depth

The visual metaphor in the universe of photographer Tatsuya Tanaka: architecturization of a miniature world

La obra del fotógrafo japonés Tatsuya Tanaka (1981) ha suscitado mucho interés en los últimos tiempos. Su discurso parte de la metáfora visual (de la que tantos fotógrafos han bebido a lo largo de la historia desde los inicios de la fotografía, y especialmente en las vanguardias) pero, a diferencia de éstas, la circunscribe a un entorno cultural netamente japonés: con unas miniaturas que pueblan sus imágenes que vinculan su obra al mitate artesanal nipón, y a los dioramas que ya formulara Daguerre, que reconstruían escenas sugerentes de la vida cotidiana. Estudiaremos cuatro piezas con una metodología consistente en análisis fotográfico, y una entrevista exclusiva que nos ha concedido el propio autor. Nuestras conclusiones son que su propuesta es radicalmente referencial, que entronca con la tradición artística japonesa más atávica pero que, sin embargo, es profundamente generacional y pensado para un público seguidor de los social media, especialmente instagram, donde Tatsuya Tanaka acumula más de 4 millones de seguidores con solo tres libros publicados.The work of the Japanese photographer Tatsuya Tanaka (1981) has recently attracted a great deal of interest. His discourse is based on the visual metaphor (from which so many photographers have drawn throughout history since the beginnings of photography, and especially in the avant-garde) but, unlike the latter, he confines it to a distinctly Japanese cultural environment: with miniatures that populate his images, linking his work to Japanese artisanal mythology, and to the dioramas formulated by Daguerre, which reconstructed suggestive scenes of everyday life. We will study four pieces with a methodology consisting of photographic analysis and an exclusive interview granted to us by the author himself. Our conclusions are that his proposal is radically referential, that it connects with the most atavistic Japanese artistic tradition but that, nevertheless, it is profoundly generational and designed for an audience that follows social media, especially instagram, where Tatsuya Tanaka has accumulated more than 4 million followers with only three published books