Date of Award

May 2021

Document Type


Degree Name

Master of Science (MS)



Committee Member

Benjamin R Stephens

Committee Member

Patrick Rosopa

Committee Member

Richard Tyrrell


Trip and fall events can be dangerous and result in injury. One-way trip events start is when an observer's minimum foot clearance (MFC) is smaller than the height change. One reason why the observer might not change their MFC in response to the height change is that the height change is not conspicuous. An important aspect of conspicuity is illuminance levels. In this study, we wish to explore an online method that uses digital manipulation of the amount of light in the photo to simulate illuminance levels (lightness levels). Previous studies with object detection suggest that the lower the illuminance levels the harder the object is to detect. This study found that people do indeed judge height changes as more conspicuous as the height change increases and as lightness levels increase. Major conclusions were that shadowing cues transfer well from in lab studies to pictures. Another conclusion is that there could be a danger to pedestrians at medium and low lightness levels.



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