Three-dimensional measurement using a single camera and target tracking

This thesis involves the development of a three-dimensional measurement system for digitising the surface of an object. The measurement system consists of a single camera and a four point planar target of known size. The target is hand held, and is used to probe the surface of the object being measured. The position of the target is tracked by the camera, and the contact point on the object is determined. The vision based digitising technique can be used in the industrial and engineering design fields during the product development phase. The accuracy of measurement is an important criterion for establishing the success of the 3-D measurement system, and the factors influencing the accuracy are investigated. These factors include the image processing algorithm, the intrinsic parameters of the camera, the algorithm to determine the position, and various procedural variables. A new iterative algorithm is developed to calculate position. This algorithm is evaluated, and its performance is compared to that of an analytic algorithm. Simple calibration procedures are developed to determine the intrinsic parameters, and mathematical models are constructed to justify these procedures. The performance of the 3-D measurement system is established and compared to that of existing digitising systems.