July 29, 2005
Computer generated 3-D animation of events that occurred during an accident, fire or
crime, are being widely used to demonstrate to jurors what the expert determined actually happened. A 3-D visualization presents technical and complex information to a jury in a clear way, enabling them all to “see” the facts of the case as the attorney does.
Recently, the growth in measurement technology has greatly increased the accuracy and realism available to the forensic animator. Combining this accuracy with laser-assisted photogrammetry is enabling experts, working closely with forensic animators, to accurately reconstruct events that would have been impossible or financially prohibitive, a few years ago. This high level of accuracy also greatly increases the probability of the animation being admitted into court as evidence.
The new laser scanners, now available, can capture 1 million measurements of a crime, fire or accident scene, every 10 minutes, with six millimeters of accuracy. The laser can scan a scene from a distance of 1000 feet away while cars and people are moving through it. The density and accuracy of the measurements provide a very realistic 3-D image of whatever the scanner scans. This enables the forensic animator to develop a very accurate computer generated 3-D working model of the scene.
This working model can then be enhanced using photographs to reconstruct what the scene looked like when the event occurred. Physical evidence no longer at the scene can also be reconstructed, if photographs of the evidence exist, and placed precisely within the working model of the scene.
This comprehensive 3-D working model can now be used to accurately simulate many
different scenario’s of an event. Using different variations of critical variables such as
speed, acceleration, trajectory, etc., the expert can determine which scenario most closely corrolates with the physical evidence. Conversely, the expert can also determine which scenarios are not supported by the physical evidence to determine what could not have occurred. These analyses can often be done on the computer which substantially reduces the cost and time required-especially compared with actual on-site simulations.
An additional advantage of computer generated 3-D reconstruction using a working model, is that as additional information becomes available, the working model can be quickly and at low cost, changed to include the new information and additional scenarios can be developed and tested.
Once the expert determines which scenario is best supported by the physical evidence, a compelling animation of the event is readily available. The working model not only assists the expert to determine what happened, but now can also be used to “show” the jury what happened!
The use of laser scanning assisted photogrammetry, to develop a computer generated 3-D working model of an event, (FORENSIC ANIMATION) changes the way reconstruction experts and animators work together. A much closer working relationship between the experts and the animator is needed to ensure the accuracy and the admissibility of the resulting testimony and animation. The animator must understand the science and mathematics the expert uses and the expert should understand the strength and limitations of laser assisted photogrammetry and computer generated 3-D animation.
Click on the following link to see still scenes from a forensic animation: