Accident Reconstruction & Photogrammetry

We often have the need to recreate an accident scene that was captured in a photograph. If we have one photograph and the dimensions of the object in the photo, we can locate the camera and use that to help with the geometry of other objects in the photo. What we often have is a setting with an object and a photograph of the object in the setting where we want to locate the object in the setting.  In addition to the mathematical photogrammetric methods, we have developed methods of creating a digital 3D model of the object from photographs or frame captures.

Below are some cases where we have used this method.

In this matter a crane block toppled over.  Because we had limited access to the offshore facility we created the accident scene digitally from drawings and photos.  We were then able to visit the accident scene virtually to take measurements and simulate various accident scenarios. 

Photo of Object

Photo of Object

Photo of 3D Model

Photo of 3D Model

Overlay of both Photos

Overlay of both Photos

 

A lawsuit, brought 20 years after an industrial plant was demolished,  necessitated the virtual recreation of the involved stairs and ramps from several photos and known dimensions of several common items.  From this model we were able to evaluate the railings on the stairs and ramp for their compliance with OSHA regulations.

Photo of Object

Photo of 3D Model

Overlay of both Photos

In this case, the counterweight of a loading arm fractured when the operator left the swing lock engaged.  When the arm fractured he realize his mistake and then released the lock which then allowed the fractured counterweight to fall on him.  The question was whether the tankerman on the barge (who testified that he saw the man pull the pin) could have seen the operator pull the pin. The model was able to be produced based on site measurements and photogrammetric evaluation of surveylence video frame captures.  The digital 3D model (center) was overlaid on one of the frame captures (left) to prove that the model was accurate (right).

Photo of Object

Photo of 3D Model

Overlay of both Photos

The sharp overlay of the model over the screen capture demonstrated the validity of the model.  To answer the question of what the tankerman on the barge could see we placed a "camera" in his eyeball (bottom left) to show what he would be able to see (bottom right).