Photogrammetry is the process of extracting measurements from photographs and it has applications in many fields such as cartography, architecture, archaeology, and even medicine.
In a forensic reconstruction setting, experts use photogrammetry tools to obtain measurements of scene evidence or vehicle damage. Check out here to know what software they use and how it works in great detail. We have even used the technique to efficiently obtain measurements from a single photograph or videos taken by police, media, witnesses, CCTV or unknown sources when the evidence is no longer available to directly examine.
The photogrammetry expert will optimize the results, adjust unknown parameters by accounting for a range, and refine the camera positions to define the uncertainties (which is an inherent aspect of a scientific process).
While photogrammetry is most accurate when conducted using photos taken by an expert with a calibrated high-resolution camera and coded targets, it is possible to extract measurements from other photographs.
Often, when the subject scene evidence or a vehicle is no longer available, photographs taken shortly after a loss showing the vehicles at rest or roadway evidence are all of the evidence we have available. This evidence may be useful and meaningful to us.
They can often extract information such as the parameters of the camera and its location relative to the environment. They can then also re-attend the scene and retake the photographs with measurement markers included, and use these new, enhanced photographs to locate the evidence as it would have been after the incident.