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Law Enforcement
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Analyze this
Forensic video faces technological challenges
May 22, 2006
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by James Careless
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In TV Land -- specifically the world of CSI: Crime Scene Investigation and its many spinoffs -- forensic video analysis is quick and easy. Just push a few buttons, and presto! The critical five-second clip showing the bad guy in action pops up instantly. Plus, there's no limit to picture resolution; just push another button and that nasty pixelated image on Gil Grissom's computer screen suddenly resolves itself into HDTV-like clarity.
In the real world, things are much different. Finding critical video clips can require hours of fast-forwarding through tapes or image sampling from digital video files. As for resolution limits, what you see on the screen is usually what you get. Granted, there are techniques such as frame averaging (which pull details from contiguous video frames to create higher-resolution stills) that can improve picture quality. But the "instant resolution" button used on Grissom's TV computer is yet to be introduced at GVExpo.
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| Crime scene investigators like Mitch Pilkington use VideoFOCUS Pro for forensic video analysis. |
Processing Power
Mitch Pilkington is a real crime scene investigator. Although he doesn't have a government-supplied Hummer like CSI: Miami's Horatio Caine, Pilkington does conduct forensic video analysis at the Weber Crime Scene Investigation Unit in Ogden, Utah. Established in 1992 to aid law enforcement departments in Weber County, Pilkington's CSI unit also helps federal, state, and surrounding city/county agencies upon request.
Some months ago -- having spent four days demultiplexing a multi-camera surveillance tape from a grocery store homicide scene -- Pilkington and his CSI team members decided there had to be a better, faster way to process forensic video. After much research, they invested in the VideoFOCUS Pro system from Salient Stills.
"To test VideoFOCUS before we bought it, I fed in the multiplexed grocery store video that had taken me four days to separate and organize," he told Government Video. "Instead of four days, the same process using VideoFOCUS took about 30 minutes! That was it. I was sold."
Although it resembles a nonlinear editor in some respects, VideoFOCUS is actually a video processing tool that has been specifically designed for forensic work. "In the main work area, the first image is displayed on the left," said Laura Teodosio, Salient Stills president and CEO. "On the right are a sampling of frames, based on a sampling rate specified by the user. Together, these elements allow you to get a quick overview of what you've got, and allows fast access for finding, marking, and enhancing specific frames. It's similar to an NLE timeline, but much more intuitive and user-friendly."
All told, VideoFOCUS provides fast access to desired video clips, quick scanning of digitized surveillance video fed from connected VCRs and hard drives, and the ability to enhance and then export specific images at user-defined resolutions and sizes. Kinda like CSI on TV, within reason.
In addition to providing fast access and handling of video files, VideoFOCUS is extremely user-friendly. "Our old software was very complex and hard for our staff to use," said Pilkington. "After three hours of training on VideoFOCUS, they were producing enhanced stills without a problem."
Digital Dangers
"It's ironic that, by digitally compressing video to save it on hard disks, the digital video security industry ends up discarding information that is vital to forensic video analysis," said Grant Fredericks, Avid's manager of public safety video solutions. "Add the lack of standards that currently exist in digital video recording to the fact that people are building video servers in their garages and basements, and one can understand why digital video is fraught with problems for the average CSI."
To combat these problems, Avid has teamed with Ocean Systems in developing a comprehensive suite of forensic video tools. Using Avid Media Composer Adrenaline technology and Ocean Systems dTective software, users can capture, process, and output digital video evidence without altering or changing it.
The system also works effectively with uncompressed multiplexed images. It can highlight and track suspects, plus enhance video to reveal hidden details recorded within field-based images. Avid also steps up to the plate by providing asset management tools, allowing analysts to accurately categorize evidence for archive, case organization, and for complete disclosure. Throughout the process, Avid's forensic video solution employs no compression.
Rocket Science
"A nonlinear editor by itself is not a good solution for forensic video analysis," said Gene Grindstaff, chief engineer for Intergraph's Video Analyst system. "You need to add some additional tools to make it do the job. That's what we've done with Video Analyst."
Specifically, Intergraph's forensic video solution uses Video Image Stabilization and Registration (VISAR) developed and licenced from NASA technology, which allows it to capture, analyze, enhance, and edit virtually any type of video through a Windows and Adobe Premiere-based user interface. Thanks to VISAR, Video Analyst can offer image stabilization, deinterlacing, magnification, rotation, and reposition of sampled video images.
In addition, Video Analyst can alter contrast and brightness, demultiplex an unlimited number of cameras simultaneously, frame average, and track user-selected area of interest from initial to end frame with annotation and frame centering. "We have added 30 layers of filtering to Video Analyst for maximum flexibility," said Grindstaff. "Meanwhile, our demultiplexer doesn't just separate multiplexed images for viewing, but also allows you to write each of the separated video feeds to individual files." Other features include selectable slow motion and the simultaneous application of multiple enhancement tools.
As Seen On TV
Even with the advances made by the companies above, forensic video analysis remains a heady challenge for CSIs -- real CSIs, that is. Take the migration from analog to digital video, for example. Although uncompressed analog video provides much more material for analysis than compressed digital footage, forensic video analysts increasingly have to work with digital footage simply because "the march to this technology is unstoppable," noted Fredericks.
Then there's what's being called the "CSI Effect." Having watched untold number of TV forensic analysts pluck HDTV-quality images from eyeball reflections captured on CCTV tapes, many juries are increasingly unsympathetic to the limits of actual forensic video analysis (see Government Video, April 2005). Hence, although the forensic video solutions being developed by Salient Stills, Avid/Ocean Systems, and Intergraph are far ahead of what was possible a decade ago, it's still not enough for many cases.
Nevertheless, forensic video analysis continues to prove its worth in court, on the streets, and yes, even on TV. In this case, we're thinking of the TV news, where forensically-derived video stills are helping police capture more suspects than ever before.
As for CSI and its various imitators? They will continue to be a source of annoyance for real forensic video analysts, at least until Gil Grissom markets those wonderful video enhancement tools he uses on TV.
MORE INFO
Avid Technology www.avid.com
Intergraph www.integraph.com
Ocean Systems www.oceansystems.com
Salient Stills www.salientstills.com
Weber CSI www.co.weber.ut.us/sheriff/enforcement
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