Optical three-dimensional coordinate measuring device and measurement method thereof

• US 10,267,620 B2
• Filed: 04/06/2017
• Issued: 04/23/2019
• Est. Priority Date: 04/27/2016
• Status: Active Grant

• Current Assignee: Keyence Corporation (Keyence)
• Original Assignee: Keyence Corporation (Keyence)
• Inventors: Ikebuchi, Masayasu
• Primary Examiner(s): Vo, Tung T
• Application Number:
  US15/480,433
• Publication Number:
  US 20170314910A1
• Time in Patent Office: 747 Days
• Field of Search: 348135
• CPC Class Codes: G01B 11/005 coordinate measuring machines
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 2207/30204 Marker
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G06T 7/60 Analysis of geometric attributes
• CPC Class Codes: G06T 7/73 using feature-based methods

Abstract

An optical three-dimensional coordinate measuring device of the present invention ensures both the measurement range and the measurement accuracy. The optical three-dimensional coordinate measuring device includes an imaging device, a table that is displaceable from an original position, a probe for designating a measurement position of a measurement object, a probe marker that is disposed on the probe, and a stage marker that is disposed on the table. The position and the attitude of the probe with respect to the imaging device are identified on the basis of the probe marker included in a captured image. The position and the attitude of the table with respect to the imaging device are identified on the basis of the stage marker included in a captured image. Relative position coordinates of a measurement position designated by the probe are obtained.

Claims

1. An optical three-dimensional coordinate measuring device comprising:

a stage base;

a table displacably supported to the stage base for placing a measurement object;

a stage marker disposed on the table;

a probe configured to designate a measurement position of a measurement object on the table;

a probe marker disposed on the probe;

an imaging device fixed to the stage base, for generating a first captured image including the probe marker and a second captured image including the stage marker;

a controller operably coupled to the imaging device, configured to identify a position and an attitude of the probe with respect to the imaging device on the basis of the probe marker included in the first captured image generated by the imaging device, to identify a position and an attitude of the table with respect to the imaging device on the basis of the stage marker included in the second captured image generated by the imaging device, and to obtain a relative position coordinate of a measurement position designated by the probe with respect to the table on the basis of the position and the attitude of the probe and the position and the attitude of the table with respect to the imaging device;

a geometrical element determination unit that determines, on the basis of a plurality of relative positions obtained by the controller and a previously set geometrical element, a relative position of the geometrical element; and

a dimension measurement unit that measures a desired dimension on the basis of a plurality of relative positions of geometrical elements determined by the geometrical element determination unit.

2. The optical three-dimensional coordinate measuring device according to claim 1, wherein a visual field of the imaging device is directed obliquely downward facing the table.

3. The optical three-dimensional coordinate measuring device according to claim 1, wherein the table includes a first side edge which is a closer side to the imaging device, the stage marker is disposed on the first side edge of the table.

4. The optical three-dimensional coordinate measuring device according to claim 1, further comprising a lock mechanism that fixes the table with respect to the stage base at an original position.

5. The optical three-dimensional coordinate measuring device according to claim 1, wherein

the probe marker and the stage marker are self-luminous markers, and

the probe marker and the stage marker are turned on at different timings.

6. The optical three-dimensional coordinate measuring device according to claim 1, wherein the first captured image and the second captured image are the same captured image, and the probe marker and the stage marker are included in the same captured image.

7. The optical three-dimensional coordinate measuring device according to claim 1, wherein the table is translatable in one direction.

8. The optical three-dimensional coordinate measuring device according to claim 1, wherein the table is axially rotatable.

9. The optical three-dimensional coordinate measuring device according to claim 1, further comprising a displacement resistance mechanism that is interposed between the stage base and the table and allows no displacement of the table when an external force acts on the table and a component of the external force in a displaceable direction of the table is a predetermined value or less.

10. A measurement method of an optical three-dimensional coordinate measuring device, the optical three-dimensional coordinate measuring device comprising:

a stage base,

a table displacably supported to the stage base for placing a measurement object,

a stage marker disposed on the table,

a probe configured to designate a measurement position of a measurement object on the table,

a probe marker disposed on the probe, and

an imaging device fixed to the stage base, for generating a first captured image including the probe marker and a second captured image including the stage marker,

the measurement method comprising;

a first calculation step of obtaining a first relative position coordinate of a measurement position designated by the probe with respect to the table when the table is at a first position and attitude;

a second calculation step of obtaining a second relative position coordinate of a measurement position designated by the probe with respect to the table when the table is at a second position and attitude displaced from the first position and attitude;

a measurement step of measuring, on the basis of the first relative position coordinate, a previously set first geometrical element defined on the basis of the first relative position coordinate, the second relative position coordinate, and a previously set second geometrical element defined on the basis of the second relative position coordinate, relative positions of the first geometrical element and the second geometrical element; and

measuring a desired dimension on the basis of the relative positions of the first geometrical element and the second geometrical element.