Vibration influence and error compensation of aspherical surface interferometer

Abstract

In the technology of aspherical surface measurement, the phase shifting aspherical surface interferometer have widely used, but the vibration error from the environment is the main factor that directly affects the measurement accuracy of the phase shifting interferometer. In this paper, based on the structure of lateral shearing aspherical surface interferometer, the resources and sorts of vibration error were introduced, and some methods to eliminate errors were mentioned. The vibration influence on measurement results was analyzed. In order to reduce error, a new error compensation algorithm was put forward. In this method, first, a vibration measurement theory was built. Then Based on optic-electrical detection technology and image acquisition system and image process technology, the vibration mode of lateral shearing interferometer was obtained. Finally the vibration error of fringe image can be compensated by image correction. The measurement results can be obtained by the four-step phase shifting interferogram. The theoretical analysis and simulative results demonstrate the feasibility of this approach to improve measurement accuracy.