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

A three-dimensional shape measuring device comprises:

• a laser light source;
• an object-light optical system;
• a reference-light optical system;
• a polarization element for detecting relative phase differences;
• and
• imaging means, in which
• the object-light optical system allows object light generated by irradiating a measurement target with a circulatory diffused illumination light generated from a part of light irradiated from the laser light source to be incident on the polarization element for detecting relative phase differences in a first circularly polarized light state,
• the reference-light optical system generates reference light from the other part of the light irradiated from the laser light source and allows the reference light to be incident on the polarization element for detecting relative phase differences in a second circularly polarized light state in a direction opposite to the first circularly polarized light,
• the polarization element for detecting relative phase differences transmits a component of the object light of the first circularly polarized light in a polarization direction of the polarization element for detecting relative phase differences and a component of the reference light of the second circularly polarized light in the polarization direction of the polarization element for detecting relative phase differences,
• the imaging means images a hologram image generated by interference between the object light and the reference light transmitted through the polarization element for detecting relative phase differences, and
• wherein the device is configured such that relative phase differences between the object light and the reference light transmitted through the polarization element for detecting relative phase differences are changed by rotating the polarization direction of the polarization element for detecting relative phase differences and a plurality of the hologram images with different relative phase differences are acquired.