What Does the Use of Photogrammetry Involve and How is it Useful?

Learn about the science of obtaining accurate 3D measurements from photos


Published on October 8, 2018

By Richard M. Ziernicki, Ph.D, P.E., DFE

 

 

The photogrammetry process is the process of attaining 3-dimensional information or measurements from photographs.  Sometimes, we have photographs taken two years ago by an insurance agent, the car is gone, nothing is available but some photographs from the accident scene showing some skid marks or some debris. Then, two years later, we want to reconstruct the accident.  The car is gone, or the roadway may have been modified because the tire marks aren’t going to stay forever depending on how busy that roadway is. The tire marks might stay for a couple weeks, for a couple of days, or they might stay for 6 months, if there is no heavy traffic.  If there is a lot of travel, then the skid marks won’t last too long.

 

photogrammetry used at scene inspection
Photogrammetry used at scene inspection

 

If all you have are photographs, then the question is “how can you figure out how long those skid marks are?” Instead of guessing or eye-balling it, there is a technique called photogrammetry by which we can digest and figure out the dimensions of that skid mark. Furthermore, we can find out how much crush we have of that car. By looking at the photographs with the proper software, we can learn the depth of the crush and the location of the crash.  We can measure that damage, which is very useful for engineers to calculate the speed because speed is the result of the engineering analysis, energy balance, and energy calculation, and for that you need to quantify that crash.

 

Photogrammetry used on accident vehicle
Photogrammetry used on accident vehicle