Displacement measuring apparatus

Patent metadata

Field	Value
Publication number	US-10724850-B2
Application number	US-201916601605-A
Country	US
Kind code	B2
Filing date	Oct 15, 2019
Priority date	Nov 9, 2018
Publication date	Jul 28, 2020
Grant date	Jul 28, 2020

Abstract

To enable measurement of a displacement at a predetermined position in the case in which a measurement object remains stationary and also in the case in which the measurement object moves. A light projector and a scanning part are controlled to cause measurement light to sequentially irradiate different positions of the measurement object in a case in which a scanning mode is selected. On the other hand, the light projector and the scanning part are controlled to cause the measurement light to irradiate the same positions of the measurement object in a case in which a line mode is selected. The displacement of the measurement object is measured on the basis of a received-light quantity distribution output from a light receiver.

First claim

What is claimed is:

1. A displacement measuring apparatus for measuring a displacement at a predetermined position of a measurement object, the displacement measuring apparatus comprising:
a light projector including a measurement light source and a light projection lens that receives light from the measurement light source, and the light projector configured to emit strip-shaped measurement light extending in a first direction, to the measurement object;
a scanning part configured to perform scanning using the measurement light in a second direction crossing the first direction;
a light receiver including a two-dimensional light receiving element, the two-dimensional light receiving element configured to output a received-light quantity distribution in response to receiving the measurement light that is reflected back from the measurement object;
a mode selector configured to select between a scanning mode in which the measurement light is sequentially emitted to different positions in the second direction of the measurement object and a line mode in which the measurement light is emitted to the same positions in the second direction of the measurement object;
a measurement controller configured to control the light projector and the scanning part to cause the measurement light to sequentially irradiate the different positions in the second direction of the measurement object in a case in which the scanning mode is selected by the mode selector, and the measurement controller further configured to control the light projector and the scanning part to cause the measurement light to irradiate the same positions in the second direction of the measurement object in a case in which the line mode is selected by the mode selector; and
a displacement measuring unit configured to measure the displacement of the measurement object on a basis of the received-light quantity distribution output from the light receiver.

2. The displacement measuring apparatus according to claim 1 , wherein the measurement controller is configured to, in the case in which the line mode is selected by the mode selector, cause the measurement light to irradiate the same positions in the second direction of the measurement object without moving a scanning mirror of the scanning part.

3. The displacement measuring apparatus according to claim 1 , wherein the measurement controller is configured to, in the case in which the line mode is selected by the mode selector, cause the measurement light to irradiate multiple positions that are adjacent to each other in the second direction, by moving the scanning mirror of the scanning part, and
the displacement measuring unit is configured to, in the case in which the line mode is selected by the mode selector, measure a displacement of the measurement object multiple times by acquiring a received-light quantity distribution for displacement measurement, which is output from the light receiver, each time the measurement light is emitted, and the displacement measuring unit is further configured to average the obtained multiple displacements.

4. The displacement measuring apparatus according to claim 1 , further comprising an irradiation direction adjuster configured to adjust an irradiation direction of the measurement light in the second direction in the case in which the line mode is selected by the mode selector.

5. The displacement measuring apparatus according to claim 1 , further comprising a setting information storage configured to store a result of selection between the scanning mode and the line mode.

6. The displacement measuring apparatus according to claim 1 , further comprising:
an illuminator configured to emit uniform illumination light to the measurement object;
a luminance image generator configured to generate a luminance image of the measurement object on a basis of a received-light quantity distribution for image generation, and the received-light quantity distribution for image generation being output from the light receiver that receives the illumination light reflected back from the measurement object;
a setting unit configured to receive setting of a measurement position in which the displacement is measured and to receive setting of a region for position correction in which the measurement position is corrected, in the luminance image generated by the luminance image generator;
a position correction information storage configured to store position correction information in the region set by the setting unit, in conjunction with relative position information between the position correction information and the measurement position set by the setting unit; and
a position corrector configured to, in operating the displacement measuring apparatus in the scanning mode, determine a position and a posture of the measurement object by using the position correction information stored in the position correction information storage, in a luminance image that is newly generated by the luminance image generator, to correct the measurement position by using the relative position information;
wherein the measurement controller is configured to control the light projector and the scanning part to cause the measurement light to irradiate the measurement position corrected by the position corrector,
the displacement measuring unit is configured to measure the displacement at the measurement position on a basis of the received-light quantity distribution for displacement measurement, and the received-light quantity distribution for displacement measurement is output from the light receiver when the light receiver receives the measurement light that is emitted to and is reflected from the measurement position corrected by the position corrector.

7. The displacement measuring apparatus according to claim 6 , wherein the position correction information is a part of the luminance image.

8. The displacement measuring apparatus according to claim 6 , wherein the position correction information is edge information of the luminance image.

9. The displacement measuring apparatus according to claim 6 , further comprising an edge extracting unit configured to extract an edge of the measurement object in the luminance image, and the position correction information being edge information relating to the edge extracted by the edge extracting unit.

10. The displacement measuring apparatus according to claim 9 , further comprising a display configured to display the edge, which is extracted by the edge extracting unit, in a manner superimposed on the luminance image.

Assignees

• Keyence Co Ltd

Inventors

• Fujiwara Kaoru

Classifications

• G06T2207/30108

  Industrial image inspection · CPC title

• G06T7/60

  Analysis of geometric attributes · CPC title

• G06T7/521

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

• G06T7/001

  using an image reference approach · CPC title

• G02B26/0833

  the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B) · CPC title