CHATTANOOGA, Tenn. (AP) — New three-dimensional technology will soon allow Chattanooga police to take jurors on a visual trip past the yellow crime scene tape, to the scene of a fatal shooting.
The Chattanooga Police Department is the first in Tennessee to get a Leica Geosystems ScanStation C10, which uses cameras and lasers to reproduce a crime scene on a screen in three dimensions.
Assistant Police Chief Tim Carroll told the Chattanooga Times Free Press that "instead of just seeing a picture of a bullet hole and then looking at a floor plan to see where the bullet hit, you can go in the house, turn a corner, and see the bullet right there in the wall." (http://bit.ly/uFjpq6)
It isn't like a 3D movie, where the images pop out from the screen, but it does allow the viewer — with the click of a mouse — to jump to any vantage point the scanner captured in its line of vision.
Carroll first spotted the ScanStation on a TV show: A&E's "Crime 360," which frequently features imaging pulled from scanners. By November 2010, the department had ordered two ScanStations, assigning one to the crime scene unit and the other to traffic investigations. Each cost the department $210,000 in grant money.
When the ScanStation is started, its laser travels over every square inch within a roughly 900-foot-diameter area, collecting 50,000 measurement points per second. Afterward, a built-in camera takes panoramic photos of the entire scene. The measurement data — called a "point cloud" — is matched with the pixels from the series of panoramic photos. The result is a color, three-dimensional rendition of the scene from which any linear measurement can be conducted with near precise accuracy.
Fewer than 100 law enforcement agencies in the country currently have the ScanStation C10. They include the Metropolitan Police in Washington, D.C., the Los Angeles Police Department and Chicago Police Department. The Georgia Bureau of Investigation shares four Leica scanners among its 14 agencies and wants to buy four more.
"It's now the best technology available for documenting and recording crime scenes," said GBI Special Agent Jerry Scott.
GBI agents used the scanners in September to document a Rocky Face, Ga., double homicide, in which a teenage girl and a man were found slain inside a burning house.
In court, the technology is an answer to what District Attorney Bill Cox describes as a "'CSI' effect" among modern jurors, many of whom are used to a steady diet of crime and courtroom dramas.
"People watch television, and they expect a lot of this high-tech video and audio evidence," Cox said.
Chattanooga police have made heavy use of the scanners since April. The city has since had 17 homicides and investigators have run scans at most of them.
"It has become a standard part of our initial investigation process," said police Sgt. Darrell Whitfield.
As detectives work a crime scene, the scanner's tripod stands discreetly to the side, its small green laser flitting over all objects within a 900-foot diameter.
After seven minutes, the scan is finished, and a camera starts swiveling to snap panoramic photos of every angle of the scene. Each pixel from those images is matched with a point collected by the laser. In less than half an hour, the scans can be uploaded to a computer, where software stitches together the 3D color diagrams.
"We can get an aerial view when we've never left the ground," Whitfield said. "We can be standing in front of a building, and then be looking out from one of its windows. We can see things we've never been able to see before."