Fast measurement strategy for large radius of curvature

Abstract

The method, based on searching the maximum or minimum of the metric function in the defined range that can be used to confirm the expected value, has been applied for measuring the large radius of curvature (ROC). The small step size is always needed in the searching range to ensure the measurement accuracy. But in the wide searching range, it will consume much time for finding the expected value. In order to improve the measurement efficiency, this paper proposes a fast measurement strategy for large ROC. This method uses a large step size to find a rough solution in a wide search range, and then constructs a shrunken range with a small step size based on the rough solution to quickly determine the high-precision measurement results. Simulation and experimental results show that the proposed method can be flexibly applied to different interference systems and greatly improve their measurement efficiency. For the tested spherical mirrors with ROC of 41400 mm and 1000 mm, high precision ROC can be obtained in just a few seconds.