Document Type



Lauer and Silver (1941) described a special dark room for studying acuity and visual discrimination under low levels of illumination. The length of the room was about 20 feet, thus precluding certain measurements where greater distances were required. The test objects were also stationary allowing only for measurements being made at a fixed distance. In connection with a recent study (1951) on perception of changes in relative distance and in variations thereof, it was necessary to construct a device which would not only give a greater distance potential, but which would allow for variations in speed of approach or recession and at the same time permit variations in the levels of illumination, either at the eye of the observer or that impinging upon the test object. Various problems of the laboratory necessitate the measurement of seeing or perceptual time at different levels of illumination. Other problems such as dark adaptation measurements, the relation between acuity and visual discrimination of objects, effects of headlight glare, glare reduction aids, light tolerance, effects of centerline flicker, effects of high contrast and reflectorized vehicles, taillight efficiency, problems of highway markings, effects of distraction on driving, hypnotic effects of continued driving and the effects of roadside stimuli, require such an apparatus for certain phases of experimentation. To date the application of the apparatus has been limited to measurements of the time and difficulty for perception of relative motion under various conditions of visibility, with certain patterns and with some variation in color background combinations.

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Journal Title

Proceedings of the Iowa Academy of Science





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©1951 Iowa Academy of Science, Inc.



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