Laurence R. Penn, CFVT, Senior Forensic Animation/Video Specialist

Surveillance videos often distort what they capture, making the recorded events difficult to analyze with an untrained eye. Such distortions will make otherwise geometric straight lines and edges look unnaturally bowed or curved. These distortions are often created by the type of lens on the surveillance camera since light passing through can be squeezed from a wide field of view into the narrower restrictions of the video format and resolution supported by the recording equipment. Luckily, software is available to undistort, or correct, such deformations into an image that is rectilinear; lines are returned, to the best of its ability, to their correct, geometrically straight nature. This process is also an important stage for performing photogrammetry and videogrammetry analysis where measurements are extracted from image and video data.

Included for example, is a video of a multi-lane roadway where delineating individual lanes is hindered by strong distortion of a wide-angle lens. Using filters in video analysis software, the video is undistorted, and the lanes straightened into a rectilinear image. Colored lines are superimposed over the painted skip lines for each lane, providing visual assistance to observe the vehicles traveling along the roadway including those involved in a collision.

Laurence R. Penn, CFVT, Senior Forensic Animation/Video Specialist with DJS Associates, Inc., can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.

Categories: Engineering Animation | Forensic Animation | Laurence R. Penn