Emergent Techniques for Assessment of Visual Performance (1985) / Chapter Skim
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APPENDIX A: BASIC FACTORS IN SPATIAL CONTRAST SENSITIVITY
APPENDIX A: BASIC FACTORS IN SPATIAL CONTRAST SENSITIVITY
Pages 31-36
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From page 31... ...
This peak, which is so prominent at high luminances, is generally believed to reflect the dynamic interaction between excitatory and inhibitory influences in the visual system. RETINAL LOCUS Compared with the contrast sensitivity function measured at the fovea, the contrast sensitivity function measured for eccentric retinal loci shows a progressive shift to lower spatial frequencies for both the high frequency cutoff and the frequency of peak sensitivity (Figure 11)
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From page 32... ...
For example, in order to measure maximum sensitivity at 0.5 cpd, one would need a test field 20 deg square to have 10 complete cycles. TEMPORAL CHARACTERISTICS Both the exposure duration of the grating target and the time course of its onset influence the contrast sensitivity function, especially at the lower spatial frequencies.
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FIGURE 11 A comparison of contrast sensitivity functions for the nasal visual-field half-meridian of the right eye (open symbols and continuous lines) and for the temporal half-meridian of the left eye (filled-in symbols and dashed lines)
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From page 34... ...
wherein horizontal and vertical orientations are more important in vision than are obliques. Figure 16 shows the contrast sensitivity function measured with vertical gratings and for 45 deg orientation gratings.
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. FIGURE 14 Contrast sensitivity functions for long exposure time with gradual onset and offset (sustained presentation)
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From page 36... ...
Copyright 1979 by the American Institute of Physics in the Journal of the Optical Society of America 69. FIGURE 16 Contrast sensitivity function for vertical and oblique orientations.
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