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Forensic video analysis

Presslink, a Midrand-based PR company, has recently acquired Cognitech Video Investigator accreditation.

The Cognitech system takes any type of video and digitally enhances selected images for forensic and investigative purposes. It de-multiplexes, de-interlaces, deblurs or sharpens (both stills and motion), blurs selected images (ie, for the protection of identity) and can convert images into several different popular formats.

A car numberplate can be enhanced and de-blurred to remove visual 'noise' and make the vehicle identifiable even though the detail is buried in deep shadow. Security or other video footage can be digitally analysed, enabling accurate reconstruction of filmed scenarios for evidence purposes.

Other specialised facilities include mosaic reconstruction, stabilisation (or de-stabilisation to reconstruct original images), shape matching and correlation. In this way video footage shot from a narrow alley of, for instance, a car driving past the end gap can be reconstructed as a still shot of the entire car as a single unit.

Specific measurement of areas within footage is done by means of photogrammetry. This can be used to determine trajectories or the estimated height of a suspect. A still can be taken from video footage and enhanced to assist in the identification of a suspect, ie, one person's image to be lifted from a 'riot' photograph, or to confirm an action such as a brick being thrown at a window.

The Cognitech Video Investigator program cannot alter an image in any way, only enhance it or select it and take it out of a 'noisy' background for easier identification.

All actions within the system are logged, making the entire forensic process traceable and repeatable by any other operator for the identical results - an authentication capability essential for the rules of evidence. Should there be any 'other programme' tampering with enhanced evidence, this would be easily discernable as the material would have to have been saved in the 'other program' format in order to do this.

Presslink have not only imported the hardware and software systems, but also have the US-trained and accredited personnel to operate them. The service is freely available to the South African market and cost is determined by system-time used.

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