| Popis: |
An instrument capable of highly accurate, non-contact range measurement has been developed, which is based upon the principle of projected rotating fringes. More usually known as dynamic fringe projection, it is this technique which is exploited in the dynamic automated range transducer (DART). The intensity waveform seen at the target and sensed by the detector, contains all the information required to accurately determine the fringe order. This, in turn, allows the range to be evaluated by the substitution of the fringe order into a simple algebraic expression. Various techniques for the analysis of the received intensity signals from the surface of the target have been investigated. The accuracy to which the range can be determined ultimately depends upon the accuracy to which the fringe order can be evaluated from the received intensity waveform. It is extremely important to be able to closely determine the fractional fringe order value, to achieve any meaningful results. This paper describes a number of techniques which have been used to analyze the intensity waveform, and critically appraises their suitability in terms of accuracy and required speed of operation. This work also examines the development of this instrument for three-dimensional measurements based on single or two beam systems. Using CCD array detectors, a 3-D range map of the object's surface may be produced.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
