A Novel Form Measurement System for Precision Components Using Interferometric Sub-aperture Stitching

Introduction

Nowadays there are several approaches for optical form measurement of precision components. Optical single point sensors as well as optical matrix sensors are applied for this measurement task. Scanning a specimen with a point sensor requires long measuring times. Hence, drifts of the stages or variations of the air temperature can cause measurement errors. Using a matrix sensor yields to large amounts of data, needs high computing power and may lead to difficulties due to comparably low frame rates if the object under investigation is moving. Another approach for measuring highly curved surfaces are computer generated holograms (CGH) for a Fizeau null-test, but this is expensive and needs very accurate manufacturing of the CGH as well as a precise alignment to the object under test [1].