A new phase-to-height model for measuring object shape using collimated projections of structured light

Non-contact shape measurement using structured light optical techniques has found many applications in health care and industry. The process of shape measurement consists of various stages, starting with the projection of structured light patterns and ending with the conversion of the measured phase of the captured intensity images to the required object height. Although various phase-to-height models exist in the literature, these models are usually restricted to a certain optical arrangement dedicated by the system components. Furthermore, the different approaches adopted in deriving these models employ numerous assumptions in order to simplify the analysis. This could make the derived models very sensitive to parameter variations of the model inputs. This paper presents a new approach for deriving the analytic phase-to-height model. This approach is not restricted to the system's geometry nor to the type of structured light projection employed. Therefore, it will allow us to better understand the various effects of system parameters on the measurement accuracy.