Three-dimensional shape measurement method and three-dimensional shape measurement device

摘要

This three-dimensional shape measurement method comprises: a projection step for projecting an interference fringe pattern (F) having a single spatial frequency (fi) onto an object surface; a recording step for recording the pattern (F) as a digital hologram; and a measurement step for generating a plurality of reconstructed images having different focal distances from the hologram, and deriving the distance to each point on the object surface by applying a focusing method to the pattern (F) on each of the reconstructed images. The measurement step extracts the component of the single spatial frequency (fi) corresponding to the pattern (F) from each of the reconstructed images by spatial frequency filtering, upon applying the focusing method, and makes it possible to achieve a highly accurate measurement in which the adverse effect of speckles is reduced and the advantage of a free-focus image reconstruction with holography is used effectively.

主权项

1. A method for measuring a three-dimensional shape comprising the steps of:
a projection step for projecting an interference fringe pattern (F) having a single spatial frequency (fi) onto an object surface; a recording step for recording the interference fringe pattern (F) projected on the object surface by the projection step as a hologram using a photo detector; and a measurement step for generating a plurality of reconstructed images having different focal distances from the hologram recorded by the recording step, and deriving a distance to each point on the object surface by applying a focusing method to the interference fringe pattern (F) in each of the reconstructed images, wherein the measurement step comprises an interference fringe pattern extraction step for extracting a component of the single spatial frequency (fi) corresponding to the interference fringe pattern from each of the reconstructed images by spatial frequency filtering when the focusing method is applied.