Distortion Measurement of USB-based Camera Used in a 3D Close-range Photogrammetric System

A 3D close-ranee photogrammetric system (CRP) is being developed to meet the demands of measuring the human body in the apparel industry and research to satisfy the critical conditions for measurement, such as safety, velocity and comfort. USB-based cameras are selected as detectors due to the characteristics of light weight, small volume and low cost. This research twill critically evaluate the quality of the detectors, especially its distortion, in order to guarantee the measuring accuracy of the CRP system. As an USB-based camera has small visual field and short focal length, a specially measuring method of distortion is developed in this study. And its mathematical model is explored and discussed. The distortion of an USB-based camera designed with some special performances for the CRP system development and that of a digital camera are evaluated for comparison. Results shows that only barrel distortion exists in the image shots by the USB-based camera, which are not more noticeable than those generated by a digital camera. it is concluded that the designated can satisfy the requirement for being used as the detectors in the CRP system.