FORENSIC VIDEO ANALYSIS OVERVIEW
DoubleTake Images has created a state-of-the-art propriety system of video analysis to assist law-enforcement in the enhancement of video tape and film.
On many occasions surveillance cameras or amateur videographers recorded important information on videotape or film, but the recorded images are not clear enough to be useful as evidence or in the identification of a suspect.
These problems are caused by a variety of conditions including unwanted electrical video signals on the tape which are manifested as graininess, ghost imaging or picture static. These extraneous noises are induced by both internal and external sources such as power lines, motors, and fluorescent lights. Snow is also caused by low signal level due to poor light, ineffective signal processing, low quality videotape, worn recording heads, and over-enhancement of the signal
Images captured on film rather than video do not display this characteristic nose, but at high magnifications, noise emanates from the silver halide grains in the film itself. These randomly positioned grains distort and hide fine details that are critical to the researcher. The following picture illustrates a typical example. This video image, recorded in low light with a consumer video camera shows an image of a truck whose license plate is completely illegible.
Conventional enhancement of video or film images incorporate procedures that range from simple contrast and brightness adjustments to more complex processes including gamma manipulation. There are also numerous techniques of making a picture look sharper, but they almost all involve methodologies that smooth images by averaging adjacent pixels. These techniques can be surprisingly effective but cannot add information to an image when none existed previously, and while these images may look sharper, there really is little improvement in the clarity of the picture.
Click here to see the results of Doubletake's proprietary image processing technique