Random Error Reduction Method for One-shot Shape Measurement using the Grating Projection Method

Abstract

This paper proposes a measurement method to capture the surface profiles of vibrating objects with high spatial resolution. The proposed method is a one-shot surface shape measurement using a grating projection method, which incorporates a Wiener filter to reduce the random error. The measured objects are a white flat plate and a polyimide film with wrinkles. The random errors treated in this study are error components that appear in the depth direction of the photogrammetric measurement. By experimental measurement of stationary objects, it is clarified that the spatial distribution of random errors is roughly Gaussian. On the basis of this result, a Wiener filter is applied as a random error reduction method for the one-shot surface shape measurement using the grating projection method. Its effectiveness is discussed by conducting the shape measurement of the white plate model and the polyimide film. The results show that the proposed method can remove random errors from the measurement results with the same effectiveness as a traditional averaging procedure. Moreover, it is also shown that the proposed method can appropriately reduce random errors in the surface shape measurement results of vibrating objects.