Calibration requirements and procedures for a monitor-basedaugmented reality system

摘要

Augmented reality entails the use of models and their associatednrenderings to supplement information in a real scene. In order for thisninformation to be relevant or meaningful, the models must be positionednand displayed in such a way that they blend into the real world in termsnof alignments, perspectives, illuminations, etc. For practical reasonsnthe information necessary to obtain this realistic blending cannot benknown a priori, and cannot be hard wired into a system. Instead a numbernof calibration procedures are necessary so that the location andnparameters of each of the system components are known. We identify thencalibration steps necessary to build a computer model of the real worldnand then, using the monitor based augmented reality system developed atnECRC (GRASP) as an example, we describe each of the calibrationnprocesses. These processes determine the internal parameters of ournimaging devices (scan converter, frame grabber, and video camera), asnwell as the geometric transformations that relate all of the physicalnobjects of the system to a known world coordinate system