scholarly journals How does lighting direction affect shape perception of glossy and matte surfaces?

2013 ◽  
Author(s):  
Arthur Faisman ◽  
Michael S. Langer
Keyword(s):  
Shape Perception

Modifying Perceived Size of a Handled Object through Hand Image Deformation

2013 ◽  
Vol 22 (3) ◽  
pp. 255-270 ◽  
Author(s):  
Yuki Ban ◽  
Takuji Narumi ◽  
Tomohiro Tanikawa ◽  
Michitaka Hirose
Keyword(s):  
Visual Representation ◽  
Shape Perception ◽  
Size Perception ◽  
Visual Object ◽  
Display System ◽  
Haptic Interaction ◽  
Image Deformation ◽  
Virtual Objects ◽  
The Difference ◽  
Hand Image

In this study, we aim to construct a perception-based shape display system to provide users with the sensation of touching virtual objects of varying shapes using only a simple mechanism. Thus far, we have proved that identified curved surface shapes or edge angles can be modified by displacing the visual representation of the user's hand. However, using this method, we cannot emulate multifinger touch, because of spatial unconformity. To solve this problem, we focus on modifying the identification of shapes using two fingers by deforming the visual representation of the user's hand. We devised a video see-through system that enables us to change the perceived shape of an object that a user is touching visually. The visual representation of the user's hand is deformed as if the user were handling a visual object; however, the user is actually handling an object of a different shape. Using this system, we conducted two experiments to investigate the effects of visuo-haptic interaction and evaluate its effectiveness. One is an investigation on the modification of size perception to confirm that the fingers did not stroke the shape but only touched it statically. The other is an investigation on the modification of shape perception for confirming that the fingers dynamically stroked the surface of the shape. The results of these experiments show that the perceived sizes of objects handled using a thumb and other finger(s) could be modified if the difference between the size of physical and visual stimuli was in the −40% to 35% range. In addition, we found that the algorithm can create an effect of shape perception modification when users stroke the shape with multiple fingers.

Body Shape Perception and its Disturbance in Anorexia Nervosa

1984 ◽  
Vol 144 (2) ◽  
pp. 167-171 ◽  
Author(s):  
S. W. Touyz ◽  
P. J. V. Beumont ◽  
J. K. Collins ◽  
M. McCabe ◽  
J. Jupp
Keyword(s):  
Anorexia Nervosa ◽  
Body Shape ◽  
Shape Perception ◽  
Video Monitor ◽  
Normal Body ◽  
Female Patients

SummaryThe perception of body shape was studied in 15 female patients with anorexia nervosa and 15 age matched controls. A lens was used which could be manipulated to cause a horizontal distortion of an image projected onto a video monitor. The patients showed a greater tendency to over- and under-estimate their present body shape than did the controls. Further, the patients' desired body shape was significantly thinner than that of controls, as was their estimation of what constitutes a normal body shape. These findings are discussed in relation to the literature and it is suggested that they may have important implications for treatment.

scholarly journals Active palpation underlying shape perception is shaped by physiological thresholds and experience

2020 ◽  
Author(s):  
Neomi Mizrachi ◽  
Guy Nelinger ◽  
Ehud Ahissar ◽  
Amos Arieli
Keyword(s):  
High Speed ◽  
Shape Perception ◽  
Tactile Perception ◽  
Hand Movements ◽  
Hand Tracking ◽  
Experimental Session ◽  
Temporal Adaptation ◽  
Planar Shape ◽  
Contour Following ◽  
Human Participants

ABSTRACTHand movements are essential for tactile perception of objects. However, why different individuals converge on specific movement patterns is not yet clear. Focusing on planar shape perception, we tracked the hands of 11 participants while they practiced shape recognition. Our results show that planar shape perception is mediated by contour-following movements, either tangential to the contour or spatially-oscillating perpendicular to it, and by scanning movements, crossing between distant parts of the shapes’ contour. Both strategies exhibited non-uniform coverage of the shapes’ contours. We found that choice of strategy during the first experimental session was strongly correlated with two idiosyncratic parameters: participants with lower tactile resolution tended to move faster; and faster-adapting participants tended to employ oscillatory movements more often. In addition, practicing on isolated geometric features increased the tendency to use the contour-following strategy. These results provide insights into the processes of strategy selection in tactile perception.SIGNIFICANCE STATMENTHand movements are integral components of tactile perception. Yet, the specific motion strategies used to perceive specific objects and features, and their dependence on physiological features and on experience, are understudied. Focusing on planar shape perception and using high-speed hand tracking we show that human participants employ two basic palpation strategies: Contour-following and scanning. We further show that the strategy chosen by each participant and its kinematics depend strongly on the participant’s physiological thresholds – indicative of spatial resolution and temporal adaptation - and on their perceptual experience.

scholarly journals On the role of shape perception when grasping objects

2010 ◽  
Vol 2 (7) ◽  
pp. 720-720
Author(s):  
R. H. Cuijpers ◽  
E. Brenner ◽  
J. B. J. Smeets
Keyword(s):  
Shape Perception
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