Threat Factors Affecting Antipredatory Behavior in the Broad-Headed Skink (Eumeces laticeps): Repeated Approach, Change in Predator Path, and Predator's Field of View

Copeia ◽  
1997 ◽  
Vol 1997 (3) ◽  
pp. 613 ◽  
Author(s):  
William E. Cooper
Keyword(s):  
Field Of View ◽  
Factors Affecting ◽  
Antipredatory Behavior ◽  
Eumeces Laticeps

Impending Collision Judgment from an Egocentric Perspective in Real and Virtual Environments: A Review

Perception ◽  
2019 ◽  
Vol 48 (9) ◽  
pp. 769-795 ◽  
Author(s):  
Ilja T. Feldstein
Keyword(s):  
Virtual Environments ◽  
Observation Time ◽  
Field Of View ◽  
Spatial Distance ◽  
Driving Experience ◽  
Factors Affecting ◽  
The Past ◽  
Technical Factors ◽  
Potential Factors ◽  
Experimental Findings

The human egocentric perception of approaching objects and the related perceptual processes have been of interest to researchers for several decades. This article gives a literature review on numerous studies that investigated the phenomenon when an object approaches an observer (or the other way around) with the goal to single out factors that influence the perceptual process. A taxonomy of metrics is followed by a breakdown of different experimental measurement methods. Thereinafter, potential factors affecting the judgment of approaching objects are compiled and debated while divided into human factors (e.g., gender, age, and driving experience), compositional factors (e.g., approaching velocity, spatial distance, and observation time), and technical factors (e.g., field of view, stereoscopy, and display contrast). Experimental findings are collated, juxtaposed, and critically discussed. With virtual-reality devices having taken a tremendous developmental leap forward in the past few years, they have been able to gain ground in experimental research. Therefore, special attention in this article is also given to the perception of approaching objects in virtual environments and put in contrast to the perception in reality.

Temporal Estimation in the Perception of Occluded Motion

1968 ◽  
Vol 26 (2) ◽  
pp. 407-416 ◽  
Author(s):  
Horace N. Reynolds
Keyword(s):  
Moving Object ◽  
Field Of View ◽  
Stimulus Information ◽  
Opaque Screen ◽  
Factors Affecting ◽  
Background Structure ◽  
Temporal Estimation ◽  
Time Required ◽  
Perceived Speed ◽  
Occluded Motion

Ss were shown a rectangular object which moved transversely across their field of view and passed behind an opaque screen. The purpose was to investigate some of the factors affecting estimates of the time required for the occluded moving object to travel a given distance behind the screen. The factors selected for study were (1) method of viewing the moving object (pursuit, static fixation), (2) background structure (homogeneous, textured), and (3) object size. According to previous studies, these variables affect the perceived speed of a moving object and might therefore be expected to affect estimates of the duration of occluded traversal. The results did not show statistically significant differences among experimental groups, although data trends are discussed. An additional finding was that Ss significantly overestimated the duration of occluded traversal, consistent with a tendency to overestimate traversal distance. The experiment is related to Michotte's studies of “amodal perception” and discussed in terms of Gibson's stimulus information approach to perception.

Factors Affecting the Perception of Interobject Distances in Virtual Environments

1999 ◽  
Vol 8 (6) ◽  
pp. 657-670 ◽  
Author(s):  
David Waller
Keyword(s):  
Virtual Environments ◽  
Virtual Environment ◽  
Power Law ◽  
Distance Perception ◽  
Corrective Feedback ◽  
Exponential Model ◽  
Field Of View ◽  
Display Type ◽  
Factors Affecting ◽  
Feedback Display

Two experiments collectively explored four factors that may influence people's judgments of exocentric (interobject) distances in virtual environments. Participants freely navigated in a simple virtual environment and repeatedly made magnitude estimations of exocentric distances. Distances were generally overestimated. An exponential model (Stevens' power law) fit the data, and exponent estimates were generally less than unity. Geometric field of view (GFOV) and the presence of error-corrective feedback were found to have the strongest effect on accuracy. In fact, distance perception was nearly veridical when made with an 80 deg. GFOV and when receiving feedback. Display type (head-mounted versus desktop) and the presence of additional perspective cues were less influential.

Factors Affecting the Visual Fragmentation of the Field-of-View in Partial Binocular Overlap Displays

1994 ◽  
Author(s):  
Victor Klymenko ◽  
Robert W. Verona ◽  
Howard H. Beasley ◽  
John S. Martin ◽  
William E. McLean
Keyword(s):  
Field Of View ◽  
Factors Affecting

Very High Resolution Analysis of the Dynamics of a Coronal Plasmoid

1994 ◽  
Vol 144 ◽  
pp. 593-596
Author(s):  
O. Bouchard ◽  
S. Koutchmy ◽  
L. November ◽  
J.-C. Vial ◽  
J. B. Zirker
Keyword(s):  
High Resolution ◽  
Solar Eclipse ◽  
Total Solar Eclipse ◽  
Field Of View ◽  
Small Field ◽  
High Resolution Analysis ◽  
Ccd Observations ◽  
Resolution Analysis ◽  
Very High ◽  
Small Field Of View

AbstractWe present the results of the analysis of a movie taken over a small field of view in the intermediate corona at a spatial resolution of 0.5“, a temporal resolution of 1 s and a spectral passband of 7 nm. These CCD observations were made at the prime focus of the 3.6 m aperture CFHT telescope during the 1991 total solar eclipse.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Dynamic Scanning Electron Microscopy of Small Particles

1975 ◽  
Vol 33 ◽  
pp. 280-281
Author(s):  
W. Krakow ◽  
W. C. Nixon
Keyword(s):  
Electron Microscopy ◽  
Low Noise ◽  
Time Sequence ◽  
Field Of View ◽  
Video Tape ◽  
Small Particles ◽  
Polystyrene Spheres ◽  
Field Distributions ◽  
Dynamic Scanning ◽  
Scanning Electron

The scanning electron microscope (SEM) can be run at television scanning rates and used with a video tape recorder to observe dynamic specimen changes. With a conventional tungsten source, a low noise TV image is obtained with a field of view sufficient to cover the area of the specimen to be recorded. Contrast and resolution considerations have been elucidated and many changing specimens have been studied at TV rates.To extend the work on measuring the magnitude of charge and field distributions of small particles in the SEM, we have investigated their motion and electrostatic interaction at TV rates. Fig. 1 shows a time sequence of polystyrene spheres on a conducting grating surface inclined to the microscope axis. In (la) there are four particles present in the field of view, while in (lb) a fifth particle has moved into view.

STM studies of crystal growth

1991 ◽  
Vol 49 ◽  
pp. 374-375
Author(s):  
M. G. Lagally
Keyword(s):  
Crystal Growth ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Sputter Deposition ◽  
Field Of View ◽  
Scanning Tunneling ◽  
Wide Field ◽  
Tunneling Microscopy ◽  
Wide Field Of View ◽  
The One

It has been recognized since the earliest days of crystal growth that kinetic processes of all Kinds control the nature of the growth. As the technology of crystal growth has become ever more refined, with the advent of such atomistic processes as molecular beam epitaxy, chemical vapor deposition, sputter deposition, and plasma enhanced techniques for the creation of “crystals” as little as one or a few atomic layers thick, multilayer structures, and novel materials combinations, the need to understand the mechanisms controlling the growth process is becoming more critical. Unfortunately, available techniques have not lent themselves well to obtaining a truly microscopic picture of such processes. Because of its atomic resolution on the one hand, and the achievable wide field of view on the other (of the order of micrometers) scanning tunneling microscopy (STM) gives us this opportunity. In this talk, we briefly review the types of growth kinetics measurements that can be made using STM. The use of STM for studies of kinetics is one of the more recent applications of what is itself still a very young field.

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