Height Measurement using Sphere Matching Method in the Stereo Vision System

This paper describes the system to measure height of persons by triangulation using stereo vision which installs two cameras on the ceiling in a stably lighted room. We propose the sphere matching method which assumes a human head as a sphere. The feature of this measurement system is as follows:- Since a sphere template is used for head matching in the edge images of a left camera and a right camera, the proposed method is hard to be influenced of each camera's field angle.- Since the head edge in the images is used, even when there is no feature in top of the head, the human height can be measured.As the result of experiment by this system, average error 1.36 [cm] and maximum error 3.85 [cm] were gained, which means high precision on the height measurement. And height measurement process, including input of a pair of stereo images, was attained in approx. 0.8 [s] (Pentium III,1.0GHz). Note that this system is a simple setup consisting of stereo camera and a general-purpose personal computer with one video capture board installed.