Close-range Photogrammetry in Traffic Incident Management

As a component of the overall traffic incident management process, 3D measurement for accident reconstruction has gained increasing importance over recent years. Digital close-range photogrammetry displays many attributes which make it a well-suited technology for this purpose. However, traditional close-range photogrammetric approaches can pose difficulties. These include the predominance of near-planar networks of generally very poor geometry that can complicate relative orientation; the economic and practical imperative of utilising inexpensive, non-metric consumer-grade cameras; and the need for the image recording and data processing phases to be carried out by non-photogrammetrists, indeed generally by police officers. This paper overviews recent developments undertaken to enhance the applicability of close-range photogrammetry and consumer-grade digital cameras to accident reconstruction. These include the implementation of robust on-line image orientation; a method for automatic camera calibration, which employs colour coded targets; and the adoption of a highly automated data processing workflow that exhibits maximum ease of use. These developments are exemplified through reference to both the iWitness and iWitnessPRO systems for close-range photogrammetry.