There are two types of scene diagramming possible with PhotoModeler: a) using a calibrated camera to photograph a current scene, and b) working with photographs from unknown cameras of a scene from the past. On this page we discuss the first, which is using a calibrated camera to document a scene before it has been cleared of vehicles. This process is typically carried out by a police department's incident team.

The two main benefits of using photogrammetry to document an accident scene are speed and cost.

A complex scene that required accurate measurement was often captured with a surveyor's total station but this was very time consuming. There is a lot of pressure on law enforcement agencies to reopen roads as soon as possible, but they have a duty to properly document the scene - as that evidence may be needed by a court at a later date. By using their own camera and some evidence markers they can document the scene quickly and accurately, and then reopen the road far faster than if they used other measurement and diagramming techniques.

The reduced cost comes from the low cost and portability of a camera vs a total station. Within a fixed budget, an agency can get more cameras and sets of evidence markers into service vehicles than total stations.

See also the Accident Mapping with Drone / UAV page for details on that particular use.

Examples

From Photos to 3D Court Presentation

Setting up for photography post incident

This incident between a GMC pickup and a Saturn at a rural intersection was documented with photographs from a police-owned camera and evidence markers. Not only was a scene diagram created, but an orthophoto was used to check tire mark shape, and some crush measurement was done at the scene (again using PhotoModeler). The photograph shows the scene with the pickup truck in the foreground with skid marks, and the Saturn sedan in the far background on the field.

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Setting up for photography post incident A 2D diagram (Courtesy of DCM Technical Services) was created in CrashZone from the data exported from PhotoModeler. PhotoModeler is a full 3D package but can easily export data projected on a plane for 2D mapping.
2D scene diagram in CrashZone An orthophoto of part of the road surface was generated showing the skid marks. One cannot get the true shape of the skid mark in a photograph taken at ground level due to perspective distortion. The rectification and orthophoto function of PhotoModeler creates an output image that removes the perspective distortion - as if the photograph was taken from in the air over the road. The true shape of the skids can be studied in such an image.
3D diagram in CrashZone with data from PhotoModeler as input The 3D view of the 2D diagram in CrashZone is suitable for court and jury presentation, as some may find it easier to understand.

 

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Combining Aerial and Ground Photos

Setting up for photography post incident

This incident, which involved fatalities and a major vehicle fire, was photographed from the ground and from an aircraft and then modeled by one of the state police agencies. The image shows one of the aerial photos that was combined into the project.

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The image below (at left) shows PhotoModeler with some of the ground photos, and on the right is the resulting scene diagram in CrashZone:

Setting up for photography post incident Setting up for photography post incident

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Some Customers

  • Alaska State Troopers 
  • Arizona Department of Public Safety 
  • Biomechanical Research & Testing
  • Crashteams Exponent 
  • FBI
  • Federal Police Academy, Germany 
  • Knott Laboratory
  • Massachusetts State Police
  • Metropolitan Police Department of Japan 
  • Minnesota State Patrol
  • National Police Agency of Japan
  • National Transportation Safety Board
  • New Jersey State Police 
  • New York State Police
  • Northwestern University Traffic Institute 
  • Royal Canadian Mounted Police
  • San Diego Department Of Public Works 
  • Solicitor General of Canada 
  • Transportation Safety Board, Canada
  • US Naval Criminal Investigation
  • Utah Highway Patrol 
  • Washington State Patrol
  • Wisconsin State Patrol

 

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