Stereopsis and the Representation of Space

Perception ◽  
1977 ◽  
Vol 6 (3) ◽  
pp. 327-332 ◽  
Author(s):  
Raymond Klein

Four stereoblind and four normal subjects were tested on a mental rotation task. It was hypothesized that, if stereopsis is an important input for building up the perceptual system that represents three-dimensional space, then subjects lacking it ought to be deficient at mental rotations in depth. Stereoblind subjects were equally efficient at picture-plane and depth rotations, and were nonsignificantly better than normal subjects at rotations in depth. It was concluded that in the absence of stereopsis other cues are sufficient for the development of the ‘three-dimensional’ perceptual system. A puzzling paradox was raised, however, by the finding that the introspections of the two groups differed markedly.

2017 ◽  
Vol 14 (130) ◽  
pp. 20170031 ◽  
Author(s):  
Patrice Koehl

In this paper, we propose a new method for computing a distance between two shapes embedded in three-dimensional space. Instead of comparing directly the geometric properties of the two shapes, we measure the cost of deforming one of the two shapes into the other. The deformation is computed as the geodesic between the two shapes in the space of shapes. The geodesic is found as a minimizer of the Onsager–Machlup action, based on an elastic energy for shapes that we define. Its length is set to be the integral of the action along that path; it defines an intrinsic quasi-metric on the space of shapes. We illustrate applications of our method to geometric morphometrics using three datasets representing bones and teeth of primates. Experiments on these datasets show that the variational quasi-metric we have introduced performs remarkably well both in shape recognition and in identifying evolutionary patterns, with success rates similar to, and in some cases better than, those obtained by expert observers.


2013 ◽  
Vol 344 ◽  
pp. 37-40
Author(s):  
Ning Sun ◽  
Huan Yu Li ◽  
Jing Jing Gong

On the basis of Coordinate transformation analysis of the inertia parameters in three-dimensional space, according to the characteristic that the coordinate direction is existed and unique which the product of inertia is 0 when rotating the coordinate system, a new method to judge and calculate the particle information by searching for the intersection of the two lines that lead from two different coordinate origin is proposed. The processes and procedures to calculate the internal mass of rigid body are deduced theoretically. A special numerical example is given to verify the correctness of the theory. The error factors are analyzed qualitatively as well.


2021 ◽  
Vol 11 (9) ◽  
pp. 4131
Author(s):  
Moon Inder Singh ◽  
Mandeep Singh

The challenge to develop an affective Brain Computer Interface requires the understanding of emotions psychologically, physiologically as well as analytically. To make the analysis and classification of emotions possible, emotions have been represented in a two-dimensional or three-dimensional space represented by arousal and valence domains or arousal, valence and dominance domains, respectively. This paper presents the classification of emotions into four classes in an arousal–valence plane using the orthogonal nature of emotions. The average Event Related Potential (ERP) attributes and differential of average ERPs acquired from the frontal region of 24 subjects have been used to classify emotions into four classes. The attributes acquired from the frontal electrodes, viz., Fp1, Fp2, F3, F4, F8 and Fz, have been used for developing a classifier. The four-class subject-independent emotion classification results in the range of 67–83% have been obtained. Using three classifiers, a mid-range accuracy of 85% has been obtained, which is considerably better than existing studies on ERPs.


2013 ◽  
Vol 364 ◽  
pp. 785-789
Author(s):  
Hai Tao Bai ◽  
Xuan Yu Wang ◽  
Wen Jie Dong ◽  
Min Hui Pang

In this paper, researchers test the attenuation law of millimeter wave to expandable graphite of different concentrations with 3mm (8mm) artificial fog insertion loss test system, through laboratory tests and smoke device field tests. The results of tests proved that the attenuation performance of expandable graphite to 3mm wave is better than to 8mm wave, which could reach 18dBm and 16dBm respectively when the density is 60g/m3 and the optical path is 0.2m. Besides, the indoor attenuation performance of expandable graphite is better than outdoor performance, which means that meteorological conditions have great impact on the attenuation performance of expandable graphite in the field tests, and that the sedimentation of expandable graphite is quite speedy under wind-free circumstances. Therefore, it is suggested to extend the suspension time of expandable graphite as long as possible, so as to improve the anti-interference ability of expandable graphite smoke.


1997 ◽  
Vol 84 (1) ◽  
pp. 176-178
Author(s):  
Frank O'Brien

The author's population density index ( PDI) model is extended to three-dimensional distributions. A derived formula is presented that allows for the calculation of the lower and upper bounds of density in three-dimensional space for any finite lattice.


2019 ◽  
Author(s):  
Jumpei Morimoto ◽  
Yasuhiro Fukuda ◽  
Takumu Watanabe ◽  
Daisuke Kuroda ◽  
Kouhei Tsumoto ◽  
...  

<div> <div> <div> <p>“Peptoids” was proposed, over decades ago, as a term describing analogs of peptides that exhibit better physicochemical and pharmacokinetic properties than peptides. Oligo-(N-substituted glycines) (oligo-NSG) was previously proposed as a peptoid due to its high proteolytic resistance and membrane permeability. However, oligo-NSG is conformationally flexible and is difficult to achieve a defined shape in water. This conformational flexibility is severely limiting biological application of oligo-NSG. Here, we propose oligo-(N-substituted alanines) (oligo-NSA) as a new peptoid that forms a defined shape in water. A synthetic method established in this study enabled the first isolation and conformational study of optically pure oligo-NSA. Computational simulations, crystallographic studies and spectroscopic analysis demonstrated the well-defined extended shape of oligo-NSA realized by backbone steric effects. The new class of peptoid achieves the constrained conformation without any assistance of N-substituents and serves as an ideal scaffold for displaying functional groups in well-defined three-dimensional space, which leads to effective biomolecular recognition. </p> </div> </div> </div>


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