Abstract
Many practical tasks in industry require simultaneous determination of the surface shape and refractive index of a transparent object; for instance, these two sets of data can be used to inspect car panels, including glass ones, and to select and sort plastic bottles. Contact-type sensors have been widely used in conventional methods to obtain the surface shape of a transparent object. However, the measurement accuracy of contact-type sensors is susceptible to the influence of various factors. In addition, this method cannot be applied to soft or breakable objects. There are few non-contact methods available for measuring the surface shape of a transparent object. On the other hand, there are many methods available for measuring the refractive index of a transparent object, but these methods completely differ from methods of taking a surface shape measurement. To our knowledge, no method that can measure both the surface shape and refractive index of a transparent object has been presented. Therefore, our purpose was to develop an approach that could simultaneously measure both the surface shape and refractive index of a transparent object.
