Semi-Automated Crush Determination Using Coded and Non- Coded Targets with Close-Range Photogrammetry

Vehicle crush measurements have typically been done using either offset methods or punctual survey methods such as with a total station or using photogrammetry. While offset grid methods are functional in determining 2-D displacement along the x and y-axis, vertical movement along the z-axis is much harder to achieve. Using a total station to complete crush measurements around a vehicle can yield accurate measurements along all 3-axis but will require multiple station set-ups to traverse around a vehicle. Depending on the total station being used a second person may also be required to move a prism to each measurement location around the vehicle. In both the offset and total station methods, all points of interest must be measured at the time of the vehicle inspection. Using photogrammetry to determine 3-D deformation of a vehicle can result in the accuracy of a total station with only one operator and allows the versatility of measuring any number of points at any time using the available photographs. A system has been created that utilizes photogrammetric technology but greatly increases productivity by automating the camera orientation and point marking process through the use of coded and non-coded targets. This system, utilizing some of the features available in Eos System’s PhotoModeler software, will decrease the time required to map a damaged or exemplar vehicle, increase the total number of points mapped in that time and automate the process of matching the two vehicles for crush determination. For approximately 1/2 to 1/3 of the cost of a low-end total station, the collision reconstructionist can have a system that will determine a greater number of 3D measurements in less time than required for a total station. The same principles and equipment can also be used to complete many of the scene measurement requirements of a collision reconstructionist.