The SMI measures surface shape deviations of precision surfaces using wavefront technology. Full surface maps reveal shape errors to within fractions of a micrometer. From optics to metal tooling, the SMI measures radius curvature, toric radii and axis, conic constant, and surface irregularities. The SMI is configured to measure contact lenses, molds, and micro-optics. Aspheric and toric parts are easily measured without the need for reference surfaces. The SMI compares the wavefront reflected from the surface to that expected from a perfect sphere. The surface deviation is expressed in the form of
characteristic circular functions called the Zernike polynomials.