Spectral Analysis Done in Real Time
Jennifer L. Morey
Researchers from Surface Optics Corp. have developed an imaging spectroradiometer that they say can perform spectral analysis at real-time video rates. The Multiband Identification and Discrimination Imaging Spectroradiometer (Midis) could be used to detect the presence of chemical or biological weapons in hostile situations.
The Multiband Identification and Discrimination Imaging Spectroradiometer can detect even subtle spectral differences. Here, the imager detects ink used in counterfeit money, showing it as red. Courtesy of Surface Optics Corp.
The hyperspectral video camera, made up of three spectral imaging heads and a hyperspectral image processor, operates from 400 nm to 12 µm. It can capture and process complete cubes of hyperspectral imagery -- comprising two spatial dimensions and one spectral dimension -- in 1/30 s.
The volume of data involved with hyperspectral imagery has hindered spectroscopic analysis, with researchers depending on software that often takes weeks to produce meaningful results. Mark Dombrowski, vice president of new products and technologies at Surface Optics, said his company overcame this obstacle by relying on hardware instead of software, thus speeding up the process. "The Midis processor implements algorithms in hardware that can be reconfigured through software for flexibility," he said.
The big picture
By looking at an entire scene at once, the system can detect the presence of spectral features throughout an area, giving the viewer a much greater chance of finding a suspect material, Dombrowski said. After collecting the spectral information from the system, the user can identify a chemical by its spectral signature.
One possible use would be identifying weapons containing ammonium nitrate and fuel oil, an explosive staple of terrorists worldwide, Dombrowski said. The spectroradiometer could look at the dust on the outside of a vehicle to detect the presence of ammonium nitrate. If the volatile gases produced by such a mixture were present near the back of the truck instead of underneath it where they should be, the user would be alerted to a potential problem.
Other applications include identification of camouflaged military targets, space-based assessment of crop conditions on Earth, detection of illegal drug manufacturing facilities, industrial quality control and cancerous cell discrimination.
The company completed the first phase of the project, the Millennium image processor, at the end of October. The processor will be sold by itself and can accept data from most other imagers, Dombrowski said. The first imaging head -- for the short- to midwave IR range -- will be added in mid-1999, and the complete system with all three imaging heads will be released in mid-2000.
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