Method for Parametric Evaluation of 3-D Surface Imaging Systems for Applications With Moving Objects

Abstract

Medical applications in which patient movements are tracked with 3D surface imaging systems are becoming increasingly popular. The 3D imaging systems used for such applications must be able to cope with controlled and uncontrolled motions of the human body. The key factors for producing a highquality 3D representation of the moving human body are the spatial resolution, accuracy, and precision of the 3D imaging system. To our knowledge, no international standard yet exists to assess these parameters. In this paper, we propose a phantom model, a method, and parameters for the assessment of spatial resolution, accuracy, and precision to evaluate systems for the 3D imaging of moving objects. The proposed phantom model is an extension of the standard 1951 USAF resolution test chart to 3D and consists of two parallel staircases with varying step heights. The phantom model is actuated with an industrial robot. The application of our method to the Photoneo MotionCam-3D showed that their multishot structured-light mode has a higher accuracy for static and slowly moving objects (accuracy of 0.1 mm) than their single-shot structured-light mode (accuracy of 0.5 mm). However, the single-shot mode can capture fast-moving objects without much loss of accuracy and precision. This provides practical quantifications for the Photoneo MotionCam-3D. Furthermore, this confirms that the proposed phantom model, method, and parameters can be used as part of a standard to assess the spatial resolution, accuracy, and precision of systems for the 3D imaging of moving objects.