Geometric and radiometric characteristics of a prototype surveillance system

Abstract

This paper reports the research findings regarding the quality of the captured video of a prototype Near-Infrared imaging system which was developed for night-time surveillance. The prototype required the incorporation of a 3D optical stereo adapter and a set of external near-infrared filters onto the optics of a conventional video camera. The study found that the video captured by the prototype was approximately 85% of the original video camera resolution and the radial lens distortion increased from one to approximately two pixels. The distortion was easily reduced to sub-pixel value using suitable image processing techniques. The standard deviation of the 3D measurement between any two facial anthropometric marks was better than 2mm for all the tested models. The image radiometric quality was sufficient to provide accurate facial landmark identification for three test subjects. The results confirmed that the prototype was suitable for 3D spatial data capture and feature interpretation of crime suspects in court.