An implementation of the well-known Ronchi test technique, which allows for the profilometric measurement of nonrotationally symmetrical surfaces, is presented and applied to the measurement of toroidal surfaces. Both the experimental setup and the data-processing procedures are described, and parameters such as the radius of curvature of the sample surface, the orientation of its principal meridians, and the position of its vertex are measured by means of the values of the local normal to the surface obtained at a set of sampling points. Integration of these local normal values allows for the reconstruction of the three-dimensional profile of the toroidal surface considered with micrometric accuracy, and submicrometric surface details may be calculated by use of surface-fitting procedures. The density of sampling points on the surface may be tailored to fit test requirements, within certain limits that depend on selection of experimental setup.
© 2000 Optical Society of America
(120.3930) Instrumentation, measurement, and metrology : Metrological instrumentation
(120.4290) Instrumentation, measurement, and metrology : Nondestructive testing
(120.4630) Instrumentation, measurement, and metrology : Optical inspection
(120.4800) Instrumentation, measurement, and metrology : Optical standards and testing
(120.6650) Instrumentation, measurement, and metrology : Surface measurements, figure
Santiago Royo, Josep Arasa, and Carles Pizarro, "Profilometry of Toroidal Surfaces with an Improved Ronchi Test," Appl. Opt. 39, 5721-5731 (2000)