Book a FREE consultation with an Acident Reconstruction Expert
open

Photogrammetry
Take measurements from photos

Photogrammetry is a common process used by investigators who are supplied with photographs of an accident scene, but no measurements. By establishing a mathematical matrix or relationship between numbers of known points in the photograph with points in the real scene, measurements can be extracted. The use of digital cameras has greatly enhanced the process of photogrammetry.

Photogrammetry is often applied to the process of crash reconstruction in cases where photographs were taken, but measurements were not.

Many times the only evidence that exists after a collision has been cleaned up are photographs. These photographs can come from police, bystanders, news agencies and insurance adjusters. In many instances dimensional information can be derived from these photographs to provide greater detail for the collision reconstruction.

Photogrammetry Example

Car Accident Road SignClear the roads faster

Recently in an effort to reopen closed roadways more quickly on scene police investigators have used photogrammetry to speed up the process of collecting measurements. It has had very limited success for that application.

Crashteams reconstructionists have the training and computer software to take an old photograph and convert it to a top-down view, to scale. Essentially, with some reference measurements (4 known points that can be obtained after the photo is taken) the photograph can become the diagram, complete with measurements.

Often this is a procedure that becomes necessary when photographs of an accident scene have been taken by on scene investigators, but no measurements have been recorded.
Photogrammetry allows Crashteams investigators to measure the scene from the photos, many years after the fact.

Total StationHow accurate is photogrammetry?

This is a common question; especially when the entire reconstruction is based on the measurements of the scene gained by the process. It has been shown in studies to be very accurate in the hands of a trained individual, with the right camera, software, and training. Our Crashteams members are trained not only to perform these measurements in a highly precise manor, but also to help you identify any unaccuracies or outright errors in the measurements performed by another expert.

Example of good and bad photo for photogrammetry

James Dean PhotoFamous Cases

Perhaps the best example is the James Dean crash of September 30 1955. Our Mike Kennedy was asked to reconstruct that crash to answer some key issues; who was driving, impact speeds etc. No proper measurements were taken by the on scene CHP officers, but they did take photographs. Mike used the picture below to rectify and transform it to a top down view.

The wheelbase of the old Ford business coupe was used to establish the mathematical relationship between the photograph and the real scene. The transformed photo was essential to the analysis, and integrated in to the scene diagram in 2D and 3D.
Photogrammetry has been a key process to solving lots of cold cases.

Scale models of the actual vehicles were simply placed on the skid marks after the photograph was rectified. This reveals the exact orientation of the vehicles at impact, and enhances the precision for the speed calculations.

2D and 3D Scene using the converted photo

Read the full story abouth James Dean's fatal accident reconstruction.

What can Crashteams do for you?

Crashteams professionals have the capability of taking photographs of the crash scene, and converting them to either CAD drawings in any drawing file format, or to a top down image that is to scale and will serve as the foundation of a reconstruction of the event.

We can also review photogrammetry output from other reconstructionists to determine the true accuracy of their output, by testing known distances against distances between the same points in the photograph as the real scene.

Call Crashteams for more information: (877) 372-3728

Book a Free consultation to meet your local accident reconstruction expert
and receive a FREE "Litigator's Guide to Crash Reconstruction"

Book Online
Or Call: (877) 372-3728

Our Services

Crash Reconstruction

Our Crashteams reconstructionists are the most highly trained and qualified individuals in the industry.

Scene Surveys

All Crashteams experts utilize survey equipment to produce precision crash scene diagrams and 3D models.

Expert Witnesses Testimony

All Crashteams reconstructionists are qualified expert witnesses and have given testimony at all court levels and jurisdictions.

Witness Interviews

Your Crashteams experts can interview witnesses and secure detailed statements, as recorded interviews in audio and video formats.

3D Animations

Crashteams experts are all trained and certified as forensic animators. You will find it advantageous that your reconstructionist and animator are the same person.

Crash Simulation

Crashteams experts are qualified to use many different software applications to simulate the crash for the purposes of answering what if scenarios and exposing errors in the hypotheses advanced by oppsing experts.

Rebuttal Reports

You may send us reports from opposing experts and we will be able to tell you immediately if a rebuttal is useful and if so, we produce professional, objective, commentaries.

Managed Services

Crashteams have the expertise coverage and manpower to take on all the crash investigation requirements of a community as a public private partnership.