This paper describes a simple low-cost method of obtaining overhead views of accident scenes and damaged vehicles. The camera is elevated above the subject vehicle/scene using a 30-foot telescopic fiberglass pole. The camera, a light-weight 35mm, autowind, with infrared remote control, is mounted with a camera quick shoe adapter. Techniques of operation of the pole and camera are described, and optimum settings for camera angle versus field of view are provided. Because the camera operator cannot physically see what is being photographed, techniques to ensure adequate coverage of the subject are also discussed. Parallax errors must be assessed in order to ensure that the error of measurements subsequently taken from photographs are minimized. Sources of parallax error and how to minimize them are discussed. The photographic boundaries using this camera technique were established by photographing a 30 x 40 foot grid at various pole heights and focal lengths of camera lens. By examining the elements of the grid, any lens distortion could also be assessed. Finally, an actual example is given to illustrate the utility of the technique and the advantage that it offers when compared to conventional measurement techniques. (A)
Abstract