Image Processing in the Presence of Symmetry and Visual Perception of Surfaces (original) (raw)

Computational aspects in image analysis of symmetry and of its perception

International conference of the International Society for the Interdisciplinary Study of Symmetry ISIS-98, Haifa, Israel, Sept, 1998

Symmetry as a characteristic of shape and form has been widely studied both in the artistic and esthetic aspect on one hand and in the mathematical and computational aspect on the other. Symmetry is typically viewed as a discrete feature: an object is either symmetric or non-symmetric. However visual perception and natural behavior and phenomena treat symmetry as a continuous feature, relating to statements such as" one object is more symmetric than another" or" an object is more mirror symmetric than rotational symmetric". ...

Symmetry Detection through Entropy Minimization

2013

The world surrounding us is composed of objects. Object recognition is an important factor in our survival and functionality in the world. Through our senses, we learn the properties of objects and distinguish them from one another. We learn, in particular, that objects occupy "volume" and are bounded by "surfaces", the type of entities whose existence and properties are learned through a combination of senses. Eventually, our visual perception .of the external world relies on our ability to distinguish various pieces of surfaces, to integrate collections of surfaces into parts of an object, and to fill any missing information by inference and other mechanisms that develop as part of our survival strategy. Thus, a theory of visual perception of surfaces is at the heart of any comprehensive theory of human perceptual organization. First studied by Gestalt psychologists early in this century, perceptual organization concerns how retinal images are structured, how t...

Perception of 3D Symmetrical and Nearly Symmetrical Shapes

Symmetry, 2018

The human visual system uses priors to convert an ill-posed inverse problem of 3D shape recovery into a well-posed one. In previous studies, we have demonstrated the use of priors like symmetry, compactness and minimal surface in the perception of 3D symmetric shapes. We also showed that binocular perception of symmetric shapes can be well modeled by the above-mentioned priors and binocular depth order information. In this study, which used a shape-matching task, we show that these priors can also be used to model perception of near-symmetrical shapes. Our near-symmetrical shapes are asymmetrical shapes obtained from affine distortions of symmetrical shapes. We found that the perception of symmetrical shapes is closer to veridical than the perception of asymmetrical shapes is. We introduce a metric to measure asymmetry of abstract polyhedral shapes, and a similar metric to measure shape dissimilarity between two polyhedral shapes. We report some key observations obtained by analyzin...