The Accuracy of Vehicle Modeling When Using an Inversely Calibrated Camera in PhotoModeler 2021-01-0883

Photogrammetry is a commonly used and accepted technique within the field of accident reconstruction for taking measurements from photographs. Previous work has shown the accuracy of optimized close-range photogrammetry techniques to be within 2 mm compared to other high accuracy measurement techniques when using a known calibrated camera. This research focuses on the use of inverse camera close-range photogrammetry, where photographs from an unknown camera are used to model a vehicle. Photogrammetry is a measurement technique that utilizes triangulation to take measurements from photographs. The measurements are dependent on the geometry of the camera, such as the sensor size, focal length, lens type, etc. Three types of cameras were tested for accuracy; a high-end commercial camera, a point and shoot camera, and a cell phone camera. This study indicates that in a properly conducted inverse photogrammetry project, an analyst can be 95% confident the true position of a point will be within 6.25 mm (0.25 inches) of the location of the point obtained via photogrammetry.