What kinds of technology are used to create virtual crime scenes?

















Image courtesy Silicon Graphics, Inc.

Detectives swarm over the scene of a recent crime, collecting every bit of evidence they can find in order to figure out exactly what took place, who was involved and how the perpetrator did what he or she did. Unfortunately, many crimes take a long time to solve, and it is rare that the scene of a crime will remain undisturbed for the entire length of the investigation. Police need a way of preserving a crime scene so that it is exactly the same every time they return to it. Hand-drawn sketches and photographs can help establish what a crime scene looks like when police arrive, but these two-dimensional media can miss details, and they can also fail to convey the precise dimensions of the scene.


This is where virtual crime scene technology enters the equation. Some police forces around the world have begun to supplement their photographs and sketches with immersive, three-dimensional simulations of crime scenes that are rendered by computers. There are two common types of virtual crime scene creation: photogrammetry, and three-dimensional rendering based on measurements.

In three-dimensional rendering, investigators have to measure the real crime scene's dimensions and the distance between objects, often using a laser distance meter or a surveyor's total station in order to make sure all measurements are exact. Measurement data is fed into a specialized computer program by a trained operator. After some calculation, the program yields a three-dimensional rendering of the crime scene, which the operator can tweak for accuracy and immersive design.

A photogrammetry system uses a stationary tripod to take a comprehensive series of pictures of an area. This is advantageous when it comes to crime scene imaging because there's no need for trained computer programmers or graphic designers: The photogrammetry machine and computer program can automatically assemble a fully realized, 360-degree digital image of a room with very little help from an operator. Plus, the photogrammetry images are actual pictures of the scene and not just representations. The automatic picture-taking system is much more efficient than a human photographer.



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