Investigation of Interactions of Luminance Contrast and Temporal Factors in Figural Aftereffects

1968 ◽  
Vol 27 (1) ◽  
pp. 287-291 ◽  
Author(s):  
June Adam ◽  
Marion Ring
Keyword(s):  
Exposure Time ◽  
Interstimulus Interval ◽  
Luminance Contrast ◽  
Test Figure ◽  
Time Condition ◽  
Temporal Factors ◽  
Concentric Circles

An experiment was designed to investigate the possibility of interactions between luminance contrast factors and temporal factors in determining the magnitude of the concentric-circles aftereffect. 24 combinations of inducing figure exposure time, condition of test figure presentation (determined by test figure exposure time and interstimulus interval), inducing figure luminance contrast and test-figure luminance contrast, were used. No interactions were found.

Effects of Luminance Contrast Factors upon Figural Aftereffects Induced by Short Fixation Periods

1966 ◽  
Vol 22 (2) ◽  
pp. 535-541 ◽  
Author(s):  
Margaret Gibb ◽  
Ivan Freeman ◽  
June Adam
Keyword(s):  
Luminance Contrast ◽  
Test Figure ◽  
General Finding ◽  
Concentric Circles

An experiment was designed to investigate the effects of luminance contrast factors upon the concentric circles aftereffect for very short periods of fixation. The general finding was that the immediate aftereffect increased as the luminance contrast of the inducing figure increased and decreased as the luminance contrast of the test figure increased.

Sex Differences in Undershoot with Extended Exposure Time in the Rod-and-Frame Test

1974 ◽  
Vol 38 (2) ◽  
pp. 543-546 ◽  
Author(s):  
R. W. Hayes ◽  
P. H. Venables
Keyword(s):  
Sex Differences ◽  
Exposure Time ◽  
Significant Interaction ◽  
Time Effect ◽  
Time Condition ◽  
Sensitive Measure ◽  
Significant Impairment ◽  
Extended Exposure ◽  
Rod And Frame Test ◽  
Rod And Frame

In 11 male and 11 female Ss increased exposure time in the RFT gave a significant impairment in performance, as measured in absolute mean error ( p < .001), establishing that the exposure-time effect reported by the same authors in 26 female Ss also applies to males. When sign of error was taken into account, undershoot in the long exposure time condition was significantly greater than overshoot ( p < .001) and a significant interaction between sex and undershoot-overshoot was demonstrated ( p < .05). Use of long exposures gives a more sensitive measure of sex differences in premature reporting of upright in the RFT.

scholarly journals Disinhibition in concentric circles aftereffects as a function of luminance contrast

1967 ◽  
Vol 8 (12) ◽  
pp. 507-508
Author(s):  
John K. Adamowicz ◽  
Robert E. Dewar
Keyword(s):  
Luminance Contrast ◽  
Concentric Circles

Direction of a Figural Retroactive-Effect as a Function of Apparent Temporal Overlap of Test and Inducing Figures

1974 ◽  
Vol 38 (1) ◽  
pp. 91-101
Author(s):  
June Adam ◽  
Ruth Heron ◽  
Donna Cooper ◽  
Alain Hepner
Keyword(s):  
Visual Illusion ◽  
Stimulus Sequence ◽  
Test Figure ◽  
Retroactive Effect ◽  
Series Of Experiments ◽  
Concentric Circles ◽  
Attraction Effects ◽  
Temporal Overlap

In a series of experiments using a concentric circles figure the direction of the figural retroactive-effect is related to the frequency with which Ss report apparent temporal overlap of inducing and test figures under different conditions of testing. The results suggest that figural retroactive-effects showing attraction of the test figure toward the inducing figure result from S's perception of a visual illusion during the stimulus sequence. Factors determining the occurrence of both apparent temporal overlap and attraction effects are investigated.

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.

Structure images of Si, Ge and Mos2 crystals and some application to radiation damage studies

1978 ◽  
Vol 36 (1) ◽  
pp. 292-293 ◽  
Author(s):  
K. Izui ◽  
T. Nishida ◽  
S. Furuno ◽  
H. Otsu ◽  
S. Kuwabara
Keyword(s):  
Radiation Damage ◽  
Exposure Time ◽  
Gaussian Distribution ◽  
Intensity Distribution ◽  
Chromatic Aberration ◽  
Magnetic Lens

Recently we have observed the structure images of silicon in the (110), (111) and (100) projection respectively, and then examined the optimum defocus and thickness ranges for the formation of such images on the basis of calculations of image contrasts using the n-slice theory. The present paper reports the effects of a chromatic aberration and a slight misorientation on the images, and also presents some applications of structure images of Si, Ge and MoS2 to the radiation damage studies.(1) Effect of a chromatic aberration and slight misorientation: There is an inevitable fluctuation in the amount of defocus due to a chromatic aberration originating from the fluctuations both in the energies of electrons and in the magnetic lens current. The actual image is a results of superposition of those fluctuated images during the exposure time. Assuming the Gaussian distribution for defocus, Δf around the optimum defocus value Δf0, the intensity distribution, I(x,y) in the image formed by this fluctuation is given by

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