Extension Cues in Open and Closed Figures

1971 ◽  
Vol 23 (3) ◽  
pp. 311-315
Author(s):  
Norman Worrall ◽  
Diane Firth
Keyword(s):  
Three Dimensional ◽  
Visual Illusions ◽  
Two Dimensional ◽  
Line Drawings

Subjects were shown line drawings of figures differing in degree of closure, and asked what the drawings most looked like. Responses were dichotomized into “upright” (e.g. beaker) and “extended” (e.g. runway). Although, overall, about twice as many upright as extended responses were given, relatively open figures yielded about twice as many extended responses as did relatively closed figures. Converging lines as such appeared an unexpectedly weak cue for extension, and horizontal discontinuity in a drawing seemed more suggestive of extension than did vertical discontinuity. Reclassifying the responses as two- or three-dimensional showed that although two-dimensional responses were less common overall, they were three times as common in relatively closed drawings. Predictions are made relating the findings to standard visual illusions.

The Effect of Visual Illusions on the Graphical Display of Information

2010 ◽  
Vol 24 (1) ◽  
pp. 23-42 ◽  
Author(s):  
T. S. Amer ◽  
Sury Ravindran
Keyword(s):  
Decision Making ◽  
Decision Aids ◽  
Three Dimensional ◽  
Accounting Information ◽  
Theoretical Work ◽  
Visual Illusions ◽  
Graphical Display ◽  
Two Dimensional ◽  
Graphical Displays ◽  
Decision Biases

ABSTRACT: Graphical displays of business and accounting information are widely used as decision aids. Theoretical work in visual perception indicates graphs that exhibit certain characteristics create visual illusions that may result in biased decision making. This paper reports the results of an experiment that demonstrates how such two-dimensional and three-dimensional visual illusions cause viewers to make biased comparison judgments. The experiment also shows that these decision biases can be mitigated by including gridlines in both two- and three-dimensional graphs.

Apparent Shape of the Mach Book

Perception ◽  
1996 ◽  
Vol 25 (3) ◽  
pp. 313-319 ◽  
Author(s):  
Richard A Clement
Keyword(s):  
Piecewise Linear ◽  
Three Dimensional ◽  
Linear Functions ◽  
Two Dimensional ◽  
Piecewise Linear Functions ◽  
Common Edge ◽  
Edge Orientation ◽  
Line Drawings ◽  
Alternative Hypotheses

The Mach book is a two-dimensional figure which looks three-dimensional. Despite the impression of depth in the figure, the apparent shape has not been determined. It has been suggested that the book appears as part of a ‘cubic corner’, ‘as flat as possible’, or with each half rotated about its long diagonal. Alternative hypotheses as to the three-dimensional orientation of the book were tested by means of a probe-line technique. It was found that, although no hypothesis matched the results of all of the subjects, the probe-line settings of individual subjects were approximately linear or piecewise linear functions of the angles in the picture. The technique was also applied to asymmetric versions of the figure and it was found that the subjects modified their settings in accord with the constraint that the two halves of the figure must join in depth along their common edge. The findings are in agreement with models of the interpretation of line drawings in which local estimates of edge orientation in depth are formed, and subsequently checked for consistency.

The Three-Dimensional Necker Cube

2017 ◽  
Author(s):  
Nicola Bruno
Keyword(s):  
Necker Cube ◽  
Three Dimensional ◽  
Visual Illusions ◽  
Two Dimensional ◽  
Reversible Figure ◽  
Sensory Signals ◽  
Dimensional Version ◽  
Definition Of ◽  
Theoretical Issues

The Necker cube is a widely known example of a reversible figure. Perceptual reversals were first observed in engravings of crystals by the Swiss geologist Louis Albert Necker in 1832. Although Necker’s engravings were not exactly of regular cubes, the figure as it is used now can be perceived in two alternative arrangements of a three-dimensional (3D) cube. Although less widely known than the popular two-dimensional version, the 3D Necker cube is a surprisingly rich model for psychophysical investigation. This chapter summarizes relevant main results and their implications for diverse theoretical issues such as the definition of visual illusions, the role of global three-dimensional interpretations in the integration of local sensory signals, and the exploratory and multisensory nature of perceptual processes.

Three-Dimensional Müller-Lyer Illusion

2017 ◽  
Author(s):  
Patricia R. DeLucia
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Line Drawings ◽  
Lyer Illusion ◽  
Solid Objects ◽  
Important Concern ◽  
Visual Science ◽  
Level Of Processing ◽  
Practical Implications ◽  
Perception Action

Since its introduction in 1889, the Müller-Lyer illusion has incited numerous studies and explanations. Most rely on two-dimensional stimuli such as line drawings, subject to the criticism that illusions are restricted to impoverished, artificial stimuli and have little relevance to understanding of ordinary perception. The three-dimensional Müller-Lyer illusion occurs with familiar solid objects and moving observers and has been used to evaluate misapplied constancy theories, perception–action dissociations, and level of processing. The occurrence of illusions in real-world contexts, and in two-dimensional displays upon which people rely increasingly, makes them essential to understand and predict. The three-dimensional Müller-Lyer illusion has significant theoretical and practical implications and continues to be an important concern for visual science.

Three-Dimensional Perception of Planar Line Segments

Perception ◽  
1979 ◽  
Vol 8 (4) ◽  
pp. 381-388
Author(s):  
Horst W Hoyer
Keyword(s):  
Short Distance ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Line Segments ◽  
Planar Line ◽  
Line Drawings ◽  
Parallel Lines ◽  
Three Dimensional Images

Two-dimensional line drawings can be perceived as three-dimensional images if they are viewed through a grating of parallel lines placed a short distance above the drawing. The position in space of the images is a function of the angle between the lines in the drawing and those in the viewer grating.

scholarly journals Digitally Developing Medieval Fortifications

X ◽  
2020 ◽  
Author(s):  
Andreas Georgopoulos ◽  
Margarita Skamantzari ◽  
Sevi Tapinaki
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Terrestrial Laser Scanning ◽  
Two Dimensional ◽  
Line Drawings ◽  
Technological Advances ◽  
Special Challenge ◽  
Digital Documentation ◽  
Automated Methods

Modern technological advances have enabled digital automated methods to be applied for accurate and detailed documentation. Such techniques include image based modelling and terrestrial laser scanning. They can easily be adapted to perfectly suit the documentation needs for small and large objects. In this paper the digital geometric documentation of two medieval fortifications using such contemporary methods is briefly described. These are the western part of the Castle of Chios and an important part of the medieval Rhodes fortifications. The purpose of the geometric documentation for both cases was the restoration of these parts, hence detailed documentation was necessary. Conventional two-dimensional plans with digital orthophotographs were produced and from them conventional line drawings were required for the case of Chios castle. Both castle parts included cylindrical bastions, whose projection on two dimensional plans is obviously deformed. Such non-planar parts constitute a special challenge for the geometric documentation. To solve this problem the three-dimensional digital documentations of these parts were developed by using suitable development routines. Thorough presentation of all considerations for these developments are presented and the implementations are briefly described. The results of these developments are evaluated for their usefulness, accuracy, and efficiency as digital documentation products.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

Instrumentation For Quantitative Microscopy

1977 ◽  
Vol 35 ◽  
pp. 206-209
Author(s):  
B. Ralph ◽  
A.R. Jones
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Automatic Data ◽  
Phase Volume Fraction ◽  
Statistical Confidence ◽  
Resultant Data ◽  
Automatic Data Collection ◽  
Third Dimension ◽  
Evolution Of Microstructure

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.

A linearity test for thick specimens imaged by HVEM over a 180° angular range

1991 ◽  
Vol 49 ◽  
pp. 552-553
Author(s):  
Yu Liu
Keyword(s):  
Phase Contrast ◽  
Three Dimensional ◽  
Angular Range ◽  
Two Dimensional ◽  
Back Projection ◽  
Line Integral ◽  
Exponential Law ◽  
Transmission Electron ◽  
Absorption Law ◽  
Linearity Test

The image obtained in a transmission electron microscope is the two-dimensional projection of a three-dimensional (3D) object. The 3D reconstruction of the object can be calculated from a series of projections by back-projection, but this algorithm assumes that the image is linearly related to a line integral of the object function. However, there are two kinds of contrast in electron microscopy, scattering and phase contrast, of which only the latter is linear with the optical density (OD) in the micrograph. Therefore the OD can be used as a measure of the projection only for thin specimens where phase contrast dominates the image. For thick specimens, where scattering contrast predominates, an exponential absorption law holds, and a logarithm of OD must be used. However, for large thicknesses, the simple exponential law might break down due to multiple and inelastic scattering.

An Image Reconstruction System Applied to High Voltage Microscopy

1975 ◽  
Vol 33 ◽  
pp. 292-293
Author(s):  
D. E. Johnson
Keyword(s):  
High Voltage ◽  
Prior Information ◽  
Block Diagram ◽  
Three Dimensional ◽  
Real Space ◽  
Two Dimensional ◽  
Efficient Manner ◽  
Fourier Methods ◽  
Tilt Series ◽  
Methods Of Reconstruction

Increased specimen penetration; the principle advantage of high voltage microscopy, is accompanied by an increased need to utilize information on three dimensional specimen structure available in the form of two dimensional projections (i.e. micrographs). We are engaged in a program to develop methods which allow the maximum use of information contained in a through tilt series of micrographs to determine three dimensional speciman structure.In general, we are dealing with structures lacking in symmetry and with projections available from only a limited span of angles (±60°). For these reasons, we must make maximum use of any prior information available about the specimen. To do this in the most efficient manner, we have concentrated on iterative, real space methods rather than Fourier methods of reconstruction. The particular iterative algorithm we have developed is given in detail in ref. 3. A block diagram of the complete reconstruction system is shown in fig. 1.

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