Optical coherence tomography for shape and radius of curvature measurements of deeply curved machined metallic surfaces: a comparison with two-beam laser interferometry

• Radius of curvature measurement of deeply curved surfaces carried out using optical coherence tomography based on low coherence interferometry.
• Radius of curvature measurements of deeply curved surfaces done by OCT compared with two-beam laser-based Fizeau interferometer.
• Advantages and limitations of both laser-based and low-coherence interferometry methods discussed.

An application of optical coherence tomography (OCT) for measuring shape and the radius of curvature of deeply curved metallic surfaces in precision mechanical components is demonstrated. Measurements carried out by OCT technique on concave and convex hemispherical metallic surfaces generated by diamond turning process is presented. The technique is compared with a two-beam laser interferometric method for determinations of shape errors and radius of curvature. It is shown that OCT is a useful tool for three-dimensional shape determinations for deeply curved surfaces such as hemispheres and has advantages over two-beam laser interferometric method.