Three-dimensional shape measuring device, method for acquiring hologram image, and method for measuring three-dimensional shape

Abstract

[Problem] To provide a low-cost, high-precision three-dimensional shape measuring device using vibration-resistant phase shift digital holography. [Solution] A three-dimensional shape measuring device, wherein an object-light optical system allows object light to be incident on a polarization element for detecting relative phase differences in a first circularly polarized light state, a reference-light optical system allows a reference light to be incident on a polarization element for detecting relative phase differences in a second circularly polarized light state in the direction opposite from the first circularly polarized light, and the polarization element for detecting relative phase differences transmits a component of the object light, which is the first circularly polarized light, in the polarization direction of the polarization element for detecting relative phase differences, and a component of the reference light, which is the second circularly polarized light, in the polarization direction of the polarization element for detecting relative phase differences. The polarization direction of the polarization element for detecting relative phase differences is rotated to thereby vary the relative phase difference between the object light and the reference light transmitted through the polarization element for detecting relative phase differences and to acquire a plurality of hologram images having different relative phase differences.