| 摘要 |
An interferometric system for characterizing the surface of a test object, such as an aspheric surface. A white light interferogram is produced wherein the principal fringe indicates zero optical path difference between a test surface and a reference surface. Wavefronts from either of the test or reference surfaces are translated by incremental amounts. A multi-point detector array is used to make multi-point contrast readings. Points of contrast maxima for each detector point are computed by a statistical determination. A centroid function is preferred. By recording the points of maximum contrast and the incremental wavefront translation, two dimensional plots showing zero optical path differences for the two surfaces are obtained, thereby comparing the test and reference surfaces.
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