Classification of Impossible Objects

Perception ◽  
1982 ◽  
Vol 11 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Kōkichi Sugihara
Keyword(s):  
Visual Perception ◽  
Three Dimensional ◽  
Point Of View ◽  
Psychological Problems ◽  
Human Visual Perception ◽  
Psychological Study ◽  
Mathematical Point ◽  
Solid Objects ◽  
Psychological Point

A mathematical scheme is proposed for the classification of impossible objects. Impossible objects are usually defined from a psychological point of view as mental images of ‘solid objects’ which cannot exist in a real three-dimensional world. From the mathematical point of view, however, various kinds of impossibility can be observed in such objects, and they are classified according to the kinds of impossibility they possess. Since impossible objects are treated in a purely mathematical way, the results afford a powerful basis for the psychological study of human visual perception of impossible objects. Several psychological problems arising from the present results are also discussed.

scholarly journals 3D PRINTING AND 3D BIOPRINTING TO USE FOR MEDICAL APPLICATIONS

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Milan Šljivić ◽  
Dragoljub Mirjanić ◽  
Nataša Šljivić ◽  
Cristiano Fragassa ◽  
Ana Pavlović
Keyword(s):  
3D Printing ◽  
Three Dimensional ◽  
3D Models ◽  
Physical Models ◽  
Layer By Layer ◽  
3D Bioprinting ◽  
Solid Objects ◽  
Modern Methods ◽  
Digital File

The Additive manufacturing 3D printing is a process of creating a three dimensional solid objects or rapid prototyping of 3D models from a digital file, which builds layer by layer. The 3D bioprinting is a form sophisticated of 3D printing technology involving cells and tissues for the production of tissue for regenerative medicine, which is also built layer by layer into the area of human tissue or organ. This paper defines the modern methods and materials of the AM, which are used for the development of physical models and individually adjusted implants for 3D printing for medical purposes. The main classification of 3D printing and 3D bioprinting technologies are also defined by typical materials and a field of application. It is proven that 3D printing and 3D bioprinting techniques have a huge potential and a possibility to revolutionize the field of medicine.

scholarly journals Photometric Classification of Stars in the Vilnius Observatory

1973 ◽  
Vol 50 ◽  
pp. 183-185 ◽  
Author(s):  
V. Straižys
Keyword(s):  
Spatial Distribution ◽  
Chemical Composition ◽  
Stellar Evolution ◽  
Three Dimensional ◽  
Point Of View ◽  
Photometric System ◽  
Intermediate Band ◽  
Dimensional Classification

The programs of three-dimensional classification of stars using eight-color intermediate band photometric system are described. They include (1) investigation of interstellar reddening and absorption in the direction of objects significant from point of view of stellar evolution, (2) investigation of spatial distribution of stars of different spectral classes, luminosities and chemical composition, (3) the detection of unique objects.

Three-Dimensional Display Based on Human Visual Perception

2014 ◽  
Vol 41 (2) ◽  
pp. 0209007
Author(s):  
王书路 Wang Shulu ◽  
明海 Ming Hai ◽  
王安廷 Wang Anting ◽  
许立新 Xu Lixin ◽  
张涛 Zhang Tao
Keyword(s):  
Visual Perception ◽  
Three Dimensional ◽  
Human Visual Perception ◽  
Three Dimensional Display

Simulating Light Source Motion in Single Images for Enhanced Perceptual Object Detection

2012 ◽  
Vol 9 (3) ◽  
pp. 269-278
Author(s):  
Herb L Hirsch ◽  
Cathleen M Moore
Keyword(s):  
Visual Perception ◽  
Light Source ◽  
Temporal Dynamics ◽  
Three Dimensional ◽  
Human Perception ◽  
Human Visual Perception ◽  
Perceptual Object ◽  
Image Objects ◽  
Varying Coefficients ◽  
Source Motion

The SIPHER technique uses mathematically-uncomplicated processing to impart interesting effects upon a static image. Importantly, it renders certain areas of an image more perceptible than others, and draws a human observer’s attention to particular objects or portions of an image scene. By varying coefficients of the processing in a time-ordered sequence, we can create a multi-frame video wherein the frame-to-frame temporal dynamics further enhance human perception of image objects. In this article we first explain the mathematical formulations and present results from applying SIPHER to simple three-dimensional shapes. Then we explore SIPHER’s utility in enhancing visual perception of targets or objects of military interest, in imagery with some typical backgrounds. We also explore how and why these effects enhance human visual perception of the image objects.

scholarly journals STRATEGIES TO EVALUATE THE VISIBILITY ALONG AN INDOOR PATH IN A POINT CLOUD REPRESENTATION

2017 ◽  
Vol IV-2/W4 ◽  
pp. 311-317 ◽  
Author(s):  
N. Grasso ◽  
E. Verbree ◽  
S. Zlatanova ◽  
M. Piras
Keyword(s):  
Visual Perception ◽  
Point Cloud ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Space Syntax ◽  
Point Of View ◽  
Indoor Environments ◽  
Two Dimensional ◽  
Visibility Graphs ◽  
Representations Of Space

Many research works have been oriented to the formulation of different algorithms for estimating the paths in indoor environments from three-dimensional representations of space. The architectural configuration, the actions that take place within it, and the location of some objects in the space influence the paths along which is it possible to move, as they may cause visibility problems. To overcome the visibility issue, different methods have been proposed which allow to identify the visible areas and from a certain point of view, but often they do not take into account the user’s visual perception of the environment and not allow estimating how much may be complicated to follow a certain path. In the field of space syntax and cognitive science, it has been attempted to describe the characteristics of a building or an urban environment by the isovists and visibility graphs methods; some numerical properties of these representations allow to describe the space as for how it is perceived by a user. However, most of these studies are directed to analyze the environment in a two-dimensional space. In this paper we propose a method to evaluate in a quantitative way the complexity of a certain path within an environment represented by a three-dimensional point cloud, by the combination of some of the previously mentioned techniques, considering the space visible from a certain point of view, depending on the moving agent (pedestrian , people in wheelchairs, UAV, UGV, robot).

Isomerism and topicity in three- and four-dimensional space: A review

1988 ◽  
Vol 53 (11) ◽  
pp. 2675-2713 ◽  
Author(s):  
Jaroslav Jonas
Keyword(s):  
Dimensional Space ◽  
Rapid Development ◽  
Three Dimensional ◽  
Point Of View ◽  
Molecular Structures ◽  
New Findings ◽  
Chemical Behaviour ◽  
Broad Meaning ◽  
Three Dimensional Space

Isomerism is a notion of a considerably broad meaning. Not only chemists but also physicists, biologists and philosophers come across it. In the sequel, some basic problems of the contemporary understanding of the phenomenon of isomerism of molecular structures and related problems of topic relationships between homomorphic ligands and faces are dealt with. Illustrating factual material is selected within the domain of organic chemistry. With the rapid development of nomenclature in this area in mind, the issues are presented from a point of view stressing the unity of historical and logical moments. Problems arising when moving from the analysis of molecular structure models towards the analysis of real sets of molecules are highlighted. Differences between the analysis of static molecular structures in three-dimensional space and the analysis of real dynamic molecular structures in four-dimensional space are dealt with in greater detail. The method of NMR spectroscopy is discussed from this standpoint as an example of the most widespread research tool for investigating intramolecular dynamism at present. Stereo-differentiating reactions are also treated briefly and a suggestion is made to introduce into the teaching of isomerism and topicity a classification of differentiating interactions. The relationships discussed are demonstrated comprehensively using the chemical behaviour of an optically active trisubstituted cycloheptatriene-norcaradiene system as an example and, are also discussed in connection with some new findings concerning actual chiral geometries in some conventionally achiral systems. Attention is paid to didactic presentation of the topic and an attempt is made to show probable trends in future development in this domain.

scholarly journals A Quantitative Method for Estimation of Quality of Screens Color

2018 ◽  
pp. 39-46
Author(s):  
O. Kupko
Keyword(s):  
Visual Perception ◽  
Color Space ◽  
Three Dimensional ◽  
Dimensional Case ◽  
Two Dimensional ◽  
Color Spaces ◽  
Human Visual Perception ◽  
Insufficient Amount ◽  
History Of ◽  
The Difference

The history of the issue on creation of uniform color spaces is analyzed. It is noted that the calculations based on the results of spectral measurements do not adequately correspond to the human visual perception. For all existing color spaces, it has been proposed to create a uniform metric, a me­thod for determining the length, area and volume in the corresponding spaces, one that corresponds to the human visual perception. The metric is based on MacAdam ellipses, that is, on the threshold perception of the difference in colors. For each point of any color space (two or three measurements) is determined the area of space around each point, within which a person is not able to fix the difference in color. The area is characterized by either an ellipse (two-dimensional case) or an ellipsoid (three-dimensional case). To characterize an ellipse, it is necessary to have three parameters — two axes and the angle of slope. To characterize an ellipsoid, it is necessary to have five parameters — three axes and two angle of slope. The number of sections along a line, along a plane, or in a volume is a measure of length, a plane, or in a volume and sets a metric. The connection of the existing systems for determining color and visual perception of a person is carried out using scales. Scales associate the length, area or volume of any color system with a person’s visual perception. The scale depends on the point of space and the direction in which the movement takes place. As a result, a large number of scales (more than the number of colors, because it is necessary to know the angles of inclination of the ellipses) are needed, which must be agreed by the international community. To use this amount of data and for the corresponding calculations, it is necessary to have an agreed international calculation procedure. It is established, that as a result of the development of computing technology, a large amount of data and a large amount of computation are not a significant obstacle. The obstacle is an insufficient amount of consistent data, that is, it is necessary to perform additional measurements and approvals to determine the areas of space around each point of the color space within which a person is not able to fix the difference in color. A schematic diagram of the measurements and the equipment with the help of which it is possible to carry out the corresponding measurements are proposed. Estimates of the greatest labour intensity of such works are carried out. It is determined what is the most important part of these works is possible to carry out within a few years. For two-dimensional spaces (x, y and u, v), using the results of the classical work of McAdam, we determined the scales for connecting the lengths and areas in these spaces with the visual perception of the human eye. The directions in which the scales are largest or smallest are determined. For these two directions there are given scales that relate the distances and areas of the spaces (x,y and u,v) with the human visual perception. It is noted, that the work on creating the metrics has a clear phased structure, some parts of the work, i.e.: the development of software and programming, the development of stabilized radiation sources, the development of comparing tools and experimental research can be carried out independently. Conclusions and suggestions are made.

RHYNCHOLITES AND THE PROBLEM OF NARROW AND BROAD CONCEPTION OF TAXONS

2018 ◽  
pp. 12-17 ◽  
Author(s):  
I. R. Khuzina ◽  
V. N. Komarov
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Characteristics ◽  
Mass Scale ◽  
Individual Variability ◽  
Point Of View ◽  
The Other ◽  
New Taxon ◽  
Artificial System ◽  
Broad Understanding

The paper considers a point of view, based on the conception of the broad understanding of taxons. According to this point of view, rhyncholites of the subgenus Dentatobeccus and Microbeccus are accepted to be synonymous with the genus Rhynchoteuthis, and subgenus Romanovichella is considered to be synonymous with the genus Palaeoteuthis. The criteria, exercising influence on the different approaches to the classification of rhyncholites, have been analyzed (such as age and individual variability, sexual dimorphism, pathological and teratological features, degree of disintegration of material), underestimation of which can lead to inaccuracy. Divestment of the subgenuses Dentatobeccus, Microbeccus and Romanovichella, possessing very bright morphological characteristics, to have an independent status and denomination to their synonyms, has been noted to be unjustified. An artificial system (any suggested variant) with all its minuses is a single probable system for rhyncholites. The main criteria, minimizing its negative sides and proving the separation of the new taxon, is an available mass-scale material. The narrow understanding of the genus, used in sensible limits, has been underlined to simplify the problem of the passing the view about the genus to the other investigators and recognition of rhyncholites for the practical tasks.

Phonetic iconicity in the evaluative morphology of a sample of Indo-European, Niger-Congo and Austronesian languages

2010 ◽  
Vol 3 (2) ◽  
pp. 156-180 ◽  
Author(s):  
Renáta Gregová ◽  
Lívia Körtvélyessy ◽  
Július Zimmermann
Keyword(s):  
Three Dimensional ◽  
Sound Symbolism ◽  
Three Dimensional Model ◽  
Austronesian Languages ◽  
Place Of Articulation ◽  
European Languages ◽  
Phonetic Symbolism ◽  
The Individual ◽  
Core Vocabulary

Universals Archive (Universal #1926) indicates a universal tendency for sound symbolism in reference to the expression of diminutives and augmentatives. The research ( Štekauer et al. 2009 ) carried out on European languages has not proved the tendency at all. Therefore, our research was extended to cover three language families – Indo-European, Niger-Congo and Austronesian. A three-step analysis examining different aspects of phonetic symbolism was carried out on a core vocabulary of 35 lexical items. A research sample was selected out of 60 languages. The evaluative markers were analyzed according to both phonetic classification of vowels and consonants and Ultan's and Niewenhuis' conclusions on the dominance of palatal and post-alveolar consonants in diminutive markers. Finally, the data obtained in our sample languages was evaluated by means of a three-dimensional model illustrating the place of articulation of the individual segments.

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