Body image distortion in photography

This thesis investigates the theory that photography is, in terms of body image perception, an intrinsically distorting and often fattening medium. In the professional practice of photography, film and television, there is a widely held belief that the camera "adds 10lbs" to the portrayed weight of actors and presenters. The primary questions addressed here relate to the true extent of the fattening effect, to what perceptual mechanisms it can be ascribed and if it can be counteracted in common practice. Current theories in the perception of photographic images rarely, if ever discuss the medium's perceptual accuracy in recording the original scene. It is assumed by many users that most photographs convey essentially the same information they would have seen had they been present when they were taken. Further, it is generally accepted that photographs are an accurate, veridical and scientific method of record and their content should be trusted unless there is evidence of a technical failure, editing or deliberate tampering. This thesis investigates whether this level of trust is appropriate, specifically by examining the reliability of photography in relation to reproducing the face and form of human subjects. Body Image Distortion (B.I.D.) is a term normally used to describe the primary diagnostic symptom of the slimming disease, anorexia nervosa. However, it is demonstrated here that people viewing 2D photographic portraits often make very significant overestimations of size when comparing otherwise identical stereoscopic images. The conclusion is that losing stereoscopic information in conventional 2D photography will cause distortions of perceived body image, and that this is often seen as a distinct flattening and fattening effect. A second fattening effect was also identified in the use of telephoto lenses. It is demonstrated, using psychophysical experiments and geometry that these 2D images cannot convey the same spatial or volumetric information that normal human orthostereoscopic perception will give. The evidence gathered suggests that the Human Visual System requires images to be orthostereoscopic, and be captured using two cameras that mimic as closely as possible the natural vergences, angle of view, depth of field, magnification, brightness, contrast and colour to reproduce scenes as accurately as possible. The experiments reported use three different size estimation methodologies: stereoscopic versus monocular comparisons of human and virtual targets, bodyweight estimations in portraits taken at differing camera to subject distances and synoptic versus direct viewing comparisons. The three techniques were used because photographic images are typically made without disparity and accommodation/vergence information, but with magnifications that are greater than found with direct viewing of a target. By separately analysing the effects of disparity, magnification and accommodation/vergence the reported experiments show how changes in each condition can effect size estimation in photographs. The data suggest that photographs made without orthostereoscopic information will lead to predictably distorted perception and that conventional 2D imaging will almost always cause a significant flattening and fattening effect. In addition, it is argued that the conveyed jaw size, in relation to neck width is an important factor in body-weight perception and this will lead to sexually dimorphic perception: disproportionately larger estimations of bodyweight are made for female faces than male faces under the same photographic conditions

Telethrone : a situated display using retro-reflection basedmulti-view toward remote collaboration in small dynamic groups

This research identifies a gap in the tele-communication technology. Several novel technology demonstrators are tested experimentally throughout the research. The presented final system allows a remote participant in a conversation to unambiguously address individual members of a group of 5 people using non-verbal cues. The capability to link less formal groups through technology is the primary contribution. Technology-mediated communication is first reviewed, with attention to different supported styles of meetings. A gap is identified for small informal groups. Small dynamic groups which are convened on demand for the solution of specific problems may be called “ad-hoc”. In these meetings it is possible to ‘pull up a chair’. This is poorly supported by current tele-communication tools, that is, it is difficult for one or more members to join such a meeting from a remote location. It is also difficult for physically located parties to reorient themselves in the meeting as goals evolve. As the major contribution toward addressing this the ’Telethrone’ is introduced. Telethrone projects a remote user onto a chair, bringing them into your space. The chair seems to act as a situated display, which can support multi party head gaze, eye gaze, and body torque. Each observer knows where the projected user is looking. It is simpler to implement and cheaper than current comparable systems. The underpinning approach is technology and systems development, with regard to HCI and psychology throughout. Prototypes, refinements, and novel engineered systems are presented. Two experiments to test these systems are peer-reviewed, and further design & experimentation undertaken based on the positive results. The final paper is pending. An initial version of the new technology approach combined retro-reflective material with aligned pairs of cameras, and projectors, connected by IP video. A counterbalanced repeated measures experiment to analyse gaze interactions was undertaken. Results suggest that the remote user is not excluded from triadic poker game-play. Analysis of the multi-view aspect of the system was inconclusive as to whether it shows advantage over a set-up which does not support multi-view. User impressions from the questionnaires suggest that the current implementation still gives the impression of being a display despite its situated nature, although participants did feel the remote user was in the space with them. A refinement of the system using models generated by visual hull reconstruction can better connect eye gaze. An exploration is made of its ability to allow chairs to be moved around the meeting, and what this might enable for the participants of the meeting. The ability to move furniture was earlier identified as an aid to natural interaction, but may also affect highly correlated subgroups in an ad-hoc meeting. This is unsupported by current technologies. Repositioning of several onlooking chairs seems to support ’fault lines’. Performance constraints of the current system are explored. An experiment tests whether it is possible to judge remote participant eye gaze as the viewer changes location, attempting to address concerns raised by the first experiment in which the physical offsets of the IP cameras lenses from the projected eyes of the remote participants (in both directions), may have influenced perception of attention. A third experiment shows that five participants viewing a remote recording, presented through the Telethrone, can judge the attention of the remote participant accurately when the viewpoint is correctly rendered for their location in the room. This is compared to a control in which spatial discrimination is impossible. A figure for how many optically seperate retro-reflected segments is obtained through spatial anlysis and testing. It is possible to render the optical maximum of 5 independent viewpoints supporting an ’ideal’ meeting of 6 people. The tested system uses one computer at the meeting side of the exchange making it potentially deployable from a small flight case. The thesis presents and tests the utility of elements toward a system, and finds that remote users are in the conversation, spatially segmented with a view for each onlooker, that eye gaze can be reconnected through the system using 3D video, and that performance supports scalability up to the theoretical maximum for the material and an ideal meeting size

KEER2022

Avanttítol: KEER2022. DiversitiesDescripció del recurs: 25 juliol 202

A right hemisphere advantage for processing blurred faces

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Sensor Fusion in the Perception of Self-Motion

This dissertation has been written at the Max Planck Institute for Biological Cybernetics (Max-Planck-Institut für Biologische Kybernetik) in Tübingen in the department of Prof. Dr. Heinrich H. Bülthoff. The work has universitary support by Prof. Dr. Günther Palm (University of Ulm, Abteilung Neuroinformatik). Main evaluators are Prof. Dr. Günther Palm, Prof. Dr. Wolfgang Becker (University of Ulm, Sektion Neurophysiologie) and Prof. Dr. Heinrich Bülthoff.amp;lt;bramp;gt;amp;lt;bramp;gt; The goal of this thesis was to investigate the integration of different sensory modalities in the perception of self-motion, by using psychophysical methods. Experiments with healthy human participants were to be designed for and performed in the Motion Lab, which is equipped with a simulator platform and projection screen. Results from psychophysical experiments should be used to refine models of the multisensory integration process, with an mphasis on Bayesian (maximum likelihood) integration mechanisms.amp;lt;bramp;gt;amp;lt;bramp;gt; To put the psychophysical experiments into the larger framework of research on multisensory integration in the brain, results of neuroanatomical and neurophysiological experiments on multisensory integration are also reviewed

Activity in area V3A predicts positions of moving objects

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Issues in Contemporary Orthodontics

Issues in Contemporary Orthodontics is a contribution to the ongoing debate in orthodontics, a discipline of continuous evolution, drawing from new technology and collective experience, to better meet the needs of students, residents, and practitioners of orthodontics. The book provides a comprehensive view of the major issues in orthodontics that have featured in recent debates. Abroad variety of topics is covered, including the impact of malocclusion, risk management and treatment, and innovation in orthodontics