Three-dimensional measurement device

Patent metadata

Field	Value
Publication number	US-11118895-B2
Application number	US-202016874222-A
Country	US
Kind code	B2
Filing date	May 14, 2020
Priority date	Dec 7, 2017
Publication date	Sep 14, 2021
Grant date	Sep 14, 2021

Abstract

A three-dimensional measurement device includes: an optical system that splits incident light into two lights, radiates one of the two lights as measurement light to a measured object and the other of the two lights as reference light to a reference surface, and recombines the two lights into combined light to emit the combined light; a light emitter that emits predetermined light entering the predetermined optical system; an imaging system that takes an image of output light emitted from the optical system; and an image processor that performs three-dimensional measurement of a predetermined measurement area of the measured object based on an interference fringe image obtained by the imaging system. The image processor obtains intensity image data at a predetermined position along an optical axis direction at each coordinate position in the measurement area by reconstruction based on an interference fringe image of the measurement area.

First claim

The invention claimed is:

1. A three-dimensional measurement device, comprising:
a predetermined optical system that splits predetermined incident light into two lights, radiates one of the two lights as measurement light to a measured object and the other of the two lights as reference light to a reference surface, and recombines the two lights into combined light to emit the combined light;
a light emitter that emits predetermined light entering the predetermined optical system;
an imaging system that takes an image of output light emitted from the predetermined optical system; and
an image processor that performs three-dimensional measurement of a predetermined measurement area of the measured object based on an interference fringe image obtained by the imaging system, wherein
the image processor further:
obtains intensity image data at a predetermined position along an optical axis direction at each coordinate position in the measurement area by reconstruction based on an interference fringe image of the measurement area obtained by the imaging system;
obtains phase information of light at the predetermined position along the optical axis direction at each coordinate position in the measurement area by reconstruction based on the interference fringe image of the measurement area obtained by the imaging system;
determines whether the intensity image data is in a focusing state that satisfies a predetermined condition based on intensity image data at a predetermined position along the optical axis direction at a predetermined coordinate position in the measurement area;
specifies an order corresponding to the predetermined position along the optical axis direction, as an order of the predetermined coordinate position, among orders determined at a predetermined measurement range interval along the optical axis direction, upon determining that the intensity image data at the predetermined position along the optical axis direction at the predetermined coordinate position is in the focusing state; and
performs three-dimensional measurement of the predetermined coordinate position based on phase information of the predetermined coordinate position and the order of the predetermined coordinate position.

2. A three-dimensional measurement device, comprising:
a predetermined optical system that splits predetermined incident light into two lights, radiates one of the two lights as measurement light to a measured object and the other of the two lights as reference light to a reference surface, and recombines the two lights into combined light to emit the combined light;
a light emitter that emits predetermined light entering the predetermined optical system;
an imaging system that takes an image of output light emitted from the predetermined optical system; and
an image processor that performs three-dimensional measurement of a predetermined measurement area of the measured object based on an interference fringe image obtained by the imaging system, wherein
the image processor further:
obtains multiple sets of intensity image data at predetermined positions along an optical axis direction at each coordinate position in the measurement area by reconstruction based on an interference fringe image of the measurement area obtained by the imaging system, wherein the multiple sets of the intensity image data are obtained at a predetermined measurement range interval of n period in at least a predetermined range along the optical axis direction, where n is a natural number equal to or greater than 1;
determines a predetermined focusing position along the optical axis direction at a predetermined coordinate position in the measurement area based on the multiple sets of the intensity image data at the predetermined coordinate position;
specifies an order corresponding to the focusing position along the optical axis direction at the predetermined coordinate position, as an order of the predetermined coordinate position, among orders determined at the measurement range interval along the optical axis direction;
obtains phase information of light at the predetermined positions along the optical axis direction at each coordinate position in the measurement area by reconstruction based on the interference fringe image of the measurement area obtained by the imaging system; and
performs three-dimensional measurement of the predetermined coordinate position based on phase information of the predetermined coordinate position and the order of the predetermined coordinate position.

3. A three-dimensional measurement device, comprising:
a predetermined optical system that splits predetermined incident light into two lights, radiates one of the two lights as measurement light to a measured object and the other of the two lights as reference light to a reference surface, and recombines the two lights into combined light to emit the combined light;
a light emitter that emits predetermined light entering the predetermined optical system;
an imaging system that takes an image of output light emitted from the predetermined optical system; and
an image processor that performs three-dimensional measurement of a predetermined measurement area of the measured object based on an interference fringe image obtained by the imaging system, wherein
the image processor further:
obtains multiple sets of intensity image data at predetermined positions along an optical axis direction in a specific area preset in the measurement area by reconstruction based on the interference fringe image obtained by the imaging system, wherein the multiple sets of the intensity image data are obtained at a predetermined measurement range interval of n period in at least a first range along the optical axis direction, where n is a natural number equal to or greater than 1;
determines a predetermined focusing position along the optical axis direction in the specific area based on the multiple sets of the intensity image data in the specific area;
obtains multiple sets of intensity image data at predetermined positions along the optical axis direction at each coordinate position in the measurement area by reconstruction based on the interference fringe image of the measurement area obtained by the imaging system, wherein the multiple sets of the intensity image data are obtained at a predetermined measurement range interval of n period in at least a second range along the optical axis direction that is set based on the focusing position along the optical axis direction in the specific area, where n is a natural number equal to or greater than 1;
determines a predetermined focusing position along the optical axis direction at a predetermined coordinate position in the measurement area based on the multiple sets of the intensity image data at the predetermined coordinate position;
specifies an order corresponding to the focusing position along the optical axis direction at the predetermined coordinate position, as an order of the predetermined coordinate position, among orders determined at the measurement range interval along the optical axis direction;
obtains phase information of light at the predetermined positions along the optical axis direction at each coordinate position in the measurement area by reconstruction based on the interference fringe image of the measurement area obtained by the imaging system; and
performs three-dimensional measurement of the predetermined coordinate position based on phase information of the predetermined coordinate position and the order of the predetermined coordinate position.

4. The three-dimensional measurement device according to claim 1 , wherein the reconstruction is performed by obtaining complex amplitude data at the predetermined position along the optical axis direction based on the interference fringe image.

Assignees

• Ckd Corp

Inventors

• Ishigaki Hiroyuki
• Mamiya Takahiro

Classifications

• G01B2290/70

  Using polarization in the interferometer · CPC title

• G06T7/521

  from laser ranging, e.g. using interferometry; from the projection of structured light · CPC title

• G01B9/02007 Primary

  Two or more frequencies or sources used for interferometric measurement (using only beat G01B9/02003) · CPC title

• G01B9/02083

  characterised by particular signal processing and presentation · CPC title

• G01B11/24 Primary

  for measuring contours or curvatures · CPC title