Division and Orientation in the Vertical-Horizontal Illusion

1972 ◽  
Vol 34 (3) ◽  
pp. 899-902 ◽  
Author(s):  
James A. Becker
Keyword(s):  
The Other ◽  
Vertical Line ◽  
Horizontal Line

This study attempted to determine the influence of the division (bisection of the horizontal line by the vertical line) and orientation (vertical line seems longer than horizontal line) factors on the vertical-horizontal illusion. 100 Ss were divided into two groups, one with knowledge of the division and orientation factors and the other group without knowledge of these factors. The results indicated that the amount of error for the group with knowledge was significantly smaller than for the group without knowledge.

Visual and Haptic Perception of the Horizontal-Vertical Illusion

2001 ◽  
Vol 92 (1) ◽  
pp. 167-170 ◽  
Author(s):  
Crystal Marie Taylor
Keyword(s):  
Visual Perception ◽  
Haptic Perception ◽  
The Other ◽  
Vertical Line ◽  
Horizontal Line ◽  
Physical Length ◽  
Present Purpose

The horizontal-vertical illusion consists of two lines of the same length (one horizontal and the other vertical) at a 90° angle from one another forming either an inverted-T or an L-shape. The illusion occurs when the length of a vertical line is perceived as longer than the horizontal line even though they are the same physical length. The illusion has been shown both visually and haptically. The present purpose was to assess differences between the visual or haptic perception of the illusions and also whether differences occur between the inverted-T and the L-shape illusions. The current study showed a greater effect in the haptic perception of the horizontal-vertical illusion than in visual perception. There is also greater illusory susceptibility of the inverted-T than the L-shape.

A NEW METHOD OF PATTERN SHOOTING

Geophysics ◽  
1955 ◽  
Vol 20 (3) ◽  
pp. 539-564 ◽  
Author(s):  
J. O. Parr ◽  
W. H. Mayne
Keyword(s):  
Finite Number ◽  
Finite Length ◽  
Vertical Line ◽  
New Method ◽  
Horizontal Line ◽  
Wavelength Band ◽  
Continuous Band ◽  
Reversed Polarity ◽  
Multiple Detectors ◽  
Horizontal Area

In areas where reflection shooting is difficult, it is often necessary to attenuate the energy in a broad continuous band of disturbing wavelengths to less than a few hundredths of what would be recorded if all units were bunched together. The wavelength band of the attenuated energy should be adjacent to the band of reflection wavelengths received. Attenuation of the undesired energy is best accomplished with multiple detectors or charges. In many areas the pattern should attenuate energy horizontally propagated in all directions, not just in the direction of the detector line. Neither a finite number of uniformly effective, uniformly spaced units in line nor a uniformly effective sheet of finite length will accomplish this result. A system for gradation of the effectiveness of units described in this paper does produce this result (not only for in‐line disturbances but also for disturbances coming in from the side of the line). The attenuation band can be made broad with good attenuation or narrower with still better attenuation, as desired. The variation of effectiveness can be applied to detectors or charges arranged in a horizontal line, over a horizontal area, in a vertical line, or over a vertical area. The principle of varying effectiveness can also be applied to reversed‐polarity detectors in order to accentuate certain apparent wavelengths.

scholarly journals Reliable Acoustic Path and Direct-Arrival Zone Spatial Gain Analysis for a Vertical Line Array

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3462 ◽  
Author(s):  
Chunyu Qiu ◽  
Shuqing Ma ◽  
Yu Chen ◽  
Zhou Meng ◽  
Jianfei Wang
Keyword(s):  
Sound Propagation ◽  
Correlation Coefficients ◽  
Deep Ocean ◽  
Vertical Line ◽  
Horizontal Line ◽  
Acoustic Path ◽  
Vertical Arrays ◽  
Peak Structure ◽  
Line Array ◽  
Propagation Properties

A method is developed in this paper to calculate the spatial gain of a vertical line array when the plane-wave assumption is not applicable and when the oceanic ambient noise is correlated. The proposed optimal array gain (OAG), which can evaluate the array’s performance and effectively guide its deployment, can be given by an equation in which the noise gain (NG) is subtracted from the signal gain (SG); hence, a high SG and a negative NG can enhance the performance of the array. OAGs and SGs with different array locations are simulated and analyzed based on the sound propagation properties of the direct-arrival zone (DAZ) and the reliable acoustic path (RAP) using ray theory. SG and NG are related to the correlation coefficients of the signals and noise, respectively, and the vertical correlation is determined by the structures of the multipath arrivals. The SG in the DAZ is always high because there is little difference between the multipath waves, while the SG in the RAP changes with the source-receiver range because of the variety of structure in the multiple arrivals. The SG under different conditions is simulated in this work. The “dual peak” structure can often be observed in the vertical directionality pattern of the noise because of the presence of bottom reflection and deep sound channel. When the directions of the signal and noise are close, the conventional beamformer will enhance the correlation of not only the signals but also the noise; thus, the directivity of the signals and noise are analyzed. Under the condition of having a typical sound speed profile, the OAG in some areas of the DAZ and RAP can achieve high values and even exceed the ideal gain of horizontal line array 10 logN dB, while, in some other areas, it will be lowered because of the influence of the NG. The proposed method of gain analysis can provide analysis methods for vertical arrays in the deep ocean under many conditions with references. The theory and simulation are tested by experimental data.

scholarly journals Two new species of the genus Crenicichla Heckel, 1840 from the upper rio Uruguay drainage (Perciformes: Cichlidae)

2007 ◽  
Vol 5 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Carlos A. S. de Lucena
Keyword(s):  
New Species ◽  
Species Group ◽  
The Body ◽  
The Other ◽  
Horizontal Line ◽  
Lower Edge ◽  
Middle Portion ◽  
Lateral Band ◽  
Two New Species ◽  
Vertical Bars

Two new species of the genus Crenicichla from the upper rio Uruguay basin are described, Crenicichla hadrostigma and C. empheres. Both are included in the C. missioneira species group along with C. missioneira, C. minuano, C. tendybaguassu, C. igara, and C. jurubi, all occurring in the upper and middle rio Uruguay drainage. Crenicichla hadrostigma is distinguished by the conspicuous ocellated posttemporal blotch, absence of a humeral spot and lateral band, and the presence in males of nine to 16 narrow vertical bars extending from the dorsum to a horizontal line that passes through the lower edge of pectoral axilla. Crenicichla empheres is distinguished from the other species of the missioneira-group by the presence of six to eight horizontally elongate dark blotches along the middle portion of the body, slightly below the upper lateral line, absence of a lateral band, presence in males of numerous dark and irregularly arranged spots on nape, back, and sides of body, and isognathous mouth. A key to the species from rio Uruguay basin is presented.

scholarly journals Correlation between spatial resolution and ball distortion rate of panoramic radiography

2020 ◽  
Author(s):  
Han-Gyeol Yeom ◽  
Sam-Sun Lee ◽  
Jo-Eun Kim ◽  
Kyung-Hoe Huh ◽  
Won-Jin Yi ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Spatial Resolution ◽  
Panoramic Radiography ◽  
Reference Value ◽  
Vertical Line ◽  
Line Pair ◽  
Horizontal Line ◽  
Student’S T ◽  
High Degree ◽  
Distortion Rate

Abstract BackgroundThe purpose of this study was to analyze the correlation between spatial resolution and ball distortion rate of panoramic radiography and to elucidate the minimum criterion for ball distortion rate, which is very relevant to clinical readability.MethodsHorizontal and vertical spatial resolution and ball distortion rates were calculated in the same position, such as the incisor, premolar, molar, and temporomandibular joint area with various object depths corresponding to 48 mm. Three devices were evaluated. A region showing spatial resolution above the reference standard was selected, and the ball distortion rate corresponding to the same region was divided into horizontal and vertical phantom groups.The mean and standard deviation of the obtained ball distortion rates were calculated. Student’s t-test was used to statistically analyze the mean difference in ball distortion rates between vertical and horizontal phantom groups.ResultsIn all devices, the horizontal line pair phantom, but not the vertical line pair phantom, was readable in all areas measured at the line pair value of at least 1.88 lp/mm. The line pair value tended to be higher toward the center and lower toward the outside. The ball distortion rate tended to decrease closer to the center and increased further away. In addition, ball distortion rates could not be measured at some areas as they were not recognized as balls due to the high degree of distortion at the outermost and innermost sides. The number of balls satisfying the reference value using the horizontal line pair phantom was 102 (mean of ball distortion rates, 20.98; standard deviation, 15.25). The number of balls satisfying the reference value using the vertical line pair phantom was 49 (mean of ball distortion rates, 16.33; standard deviation, 14.25). However, mean ball distortion rate was not significantly different between the two groups.ConclusionsFocal layer of panoramic radiography could be evaluated by the spatial resolution using horizontal and vertical line pair phantoms and by assessing ball distortion rates through a ball-type panorama phantom. A ball distortion rate of 20% could be used as a threshold to evaluate the focal layer of panoramic radiography.

The Role of Figure Orientation and Apparent Depth in the Perception of the Horizontal—Vertical Illusion

Perception ◽  
1975 ◽  
Vol 4 (1) ◽  
pp. 79-83 ◽  
Author(s):  
Harvey R Schiffman ◽  
Jack G Thompson
Keyword(s):  
Stimulus Figure ◽  
Vertical Line ◽  
Apparent Depth ◽  
Horizontal Line ◽  
Size Constancy ◽  
Illusory Effect

An experiment was performed which examined the role of figural orientation directly, and the role of an inappropriately invoked size-constancy mechanism indirectly, in the actuation and magnitude of the horizontal—vertical illusion. When the vertical line of the stimulus figure was aligned above the horizontal line, the illusory effect was significant and positive; in contrast, when the vertical line was located below the horizontal line, the illusion was negative. Under the assumption that a vertical line can appear as a foreshortened line in depth, these findings support an explanation based on the operation of a misapplied size-constancy mechanism.

Measurement of the Shortening Effect on the Perceived Path of Stroboscopic Movement

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 288-288
Author(s):  
S Nozawa
Keyword(s):  
Three Dimensional ◽  
Vertical Axis ◽  
Horizontal Axis ◽  
The Other ◽  
Horizontal Line ◽  
Optimal Frequency ◽  
Stimulus Line ◽  
Factors Influencing ◽  
Parallel Motion ◽  
Axis I

When two vertical short lines are alternately flashed at certain SOAs, a shortening of the apparent path of the stroboscopic movement is perceived. In the experiments reported here, factors influencing the shortening effect were studied with lines created on a CRT display. Experiment 1 was designed to study the effect of SOA. Each stimulus line was always presented for 100 ms, but intervals were varied in the range from 25 to 800 ms. With short and long SOAs almost no shortening illusion was observed, whereas the SOA for optimal stroboscopic motion (200 ms) also produced the largest illusion (ca 16%). This agrees with the classic study by Scholz (1924 Psychologische Forschung5 219 – 272) who found the largest illusion (25%) at the optimal frequency for stroboscopic motion. Experiment 2 dealt with the effect of inversions (I), mirror reflections (M), and rotations (R) of the line during the stroboscopic movement (see Kolars and Pomerantz, 1971 Journal of Experimental Psychology87 99 – 108). The particular movements were signalled by means of a short horizontal line added to one end of each of the two vertical lines of experiment 1. The configurations were (1), signifying parallel motion in one plane; (2), locomotion with rotation around the vertical axis (M); (3), locomotion with rotation around the horizontal axis (I); and (4), locomotion with rotation in the plane of the display (R). In all these conditions, the shortening illusion was significantly larger than in experiment 1. The differences between the four conditions were not statistically significant, but the illusion under condition (1) seemed smaller than in the other three conditions. With SOAs for optimal stroboscopic motion, ‘rotation’ paths tended to appear three-dimensional.

Direct comparison of the haptic and visual horizontal–vertical illusions using traditional figures and single lines

2012 ◽  
Vol 25 (0) ◽  
pp. 182
Author(s):  
Jacqui Howell ◽  
Mark Symmons ◽  
George Van Doorn
Keyword(s):  
Literature Review ◽  
Stimulus Size ◽  
Current Paper ◽  
Vertical Line ◽  
Percentage Error ◽  
Horizontal Line ◽  
Visual Phenomenon ◽  
Critical Literature

The horizontal–vertical illusion (HVI) has been widely and extensively reported as a visual phenomenon in which a vertical line is perceived as shorter than a horizontal line of the same length. Like a number of geometric illusions, the HVI has also been found to occur haptically, though there is less agreement in the literature as to the extent and direction of the illusion. The relatively small number of haptic HVI papers coupled with a variety of stimuli and procedures used make it difficult to make direct comparison between the visual and haptic versions of the illusion. After a brief critical literature review, the current paper reports a study in which the visual and haptic HVIs are directly compared. In a bid to reconcile previous shortcomings, three sets of stimuli were used: L-figures, inverted T-figures, and separated horizontal and vertical lines. The stimuli were presented in two lengths: 3 and 9 cm. The dependent variable was percentage error between the horizontal and vertical — no error represents an absence of illusion. As expected, inverted T-figures produced an illusion significantly stronger than both the L-figures and single lines, which in turn did not differ from each other. Further, the illusion was present to the same extent in both modalities. Stimuli of 9 cm produced relatively stronger illusions than those that measured 3 cm, and stimulus size interacted with modality. The consequences of these findings for earlier research and proffered suggestions as to what causes this and other illusions are discussed.

Properties of random functions

1956 ◽  
Vol 52 (4) ◽  
pp. 672-686 ◽  
Author(s):  
D. S. Palmer
Keyword(s):  
Cross Correlation ◽  
The Other ◽  
Horizontal Line ◽  
Time Lags ◽  
Frequency Distributions ◽  
Random Functions ◽  
Wave Radio ◽  
Long Wave ◽  
Radio Signals ◽  
Highly Correlated

ABSTRACTThis paper deals with the relationships of the maxima, minima and zeros of two random functions of known autocorrelations and cross-correlation, based on the work of Rice(4). Ratcliffe(3) and Briggs and Spencer(2) discuss a similar problem in connexion with a ‘Phillips Record’ of an experiment in ionospheric reflexion. In this experiment there are two highly correlated reflected signals, their maxima coming close together, and the record shows the time lags between a maximum on one signal and a maximum on the other. Briggs and Page (1) have made an experimental study of the distribution of the differences between the positions of the maxima of two highly correlated random functions, using EDSAC to construct the functions. In §§ 3–7 the frequency distributions of intervals between successive zeros and maxima, and of the lengths of intercepts by a horizontal line, are considered. This has applications to the study of the fading of long-wave radio signals, where the tune differences between successive maxima of the amplitude have been investigated.

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