Granted Patent B2

US 12,613,085 · App. 17/955,051 · Granted Apr 28, 2026

Inventor: Michael Nahum (Seattle, WA)

Assignee: Mitutoyo Corporation

G01B3/18G06T7/13G06T7/70H04N23/631G06T2207/30204

Abstract

Claims (54)

1 . A micrometer head displacement system, comprising:

an imaging portion comprising at least one camera and configured to acquire images of a micrometer head, the micrometer head comprising:

a coarse scale and a coarse fiducial line configured to move relative to one another for indicating a coarse scale measurement; and

a fine scale and a fine fiducial line configured to move relative to one another for indicating a fine scale measurement;

a display configured to indicate the micrometer head displacement, wherein the display is configured to provide a positive indication confirming proper positioning of the imaging portion relative to the micrometer head;

one or more processors; and

a memory coupled to the one or more processors and storing program instructions that when executed by the one or more processors cause the one or more processors to at least:

acquire at least one image of the micrometer head from the imaging portion;

determine a coarse measurement based at least in part on the at least one image, wherein the coarse measurement corresponds to a coarse relative position between the coarse scale and the coarse fiducial line;

determine a fine measurement based at least in part on the at least one image and based on calculating an interpolated position of the fine fiducial line, wherein the fine measurement corresponds to a fine relative position between the fine scale and the fine fiducial line; and

determine a micrometer head displacement based at least in part on summing the coarse measurement with the fine measurement.

2 . The micrometer head displacement system of claim 1 , wherein the display is configured to include a view window which displays the at least one image of the micrometer head.

3 . The micrometer head displacement system of claim 1 , wherein the one or more processors confirm the proper positioning when the fine fiducial line is positioned at a center of a field of view of the imaging portion and a substantially equal number of fine measurement markings appear on either side of the fine fiducial line.

4 . The micrometer head displacement system of claim 1 , wherein the one or more processors are configured to determine the coarse measurement, the fine measurement, and the micrometer head displacement in response to a user action responsive to the positive indication.

5 . The micrometer head displacement system of claim 1 , wherein the micrometer head displacement is stored in the memory.

6 . The micrometer head displacement system of claim 1 , comprising a motor system configured to operate the micrometer head, wherein the one or more processors are configured to drive the motor system based on the micrometer head displacement.

7 . The micrometer head displacement system of claim 1 , wherein the calculating the interpolated position of the fine fiducial line includes:

on the fine scale, determining a first fine measurement marking which is closest and does not exceed the fine fiducial line, and determining a first fine measurement based on the first fine measurement marking;

determining a position of the fine fiducial line within a first distance between the first fine measurement marking and a second fine measurement marking, which is adjacent to the first fine measurement marking wherein the position of the fine fiducial line lies between the first and second fine measurement markings; and

determining a ratio between a second distance from the first fine measurement marking to the position of the fine fiducial line and the first distance from the first fine measurement marking to the second fine measurement marking, and calculating the interpolated position of the fine fiducial line based on the ratio.

8 . The micrometer head displacement system of claim 7 , wherein the determining the fine measurement includes:

summing the first fine measurement which is based on the first fine measurement marking with an interpolated fine measurement which is based on the interpolated position of the fine fiducial line.

9 . The micrometer head displacement system of claim 1 , wherein the calculating the interpolated position of the fine fiducial line includes utilizing a contrast curve analysis to determine a location of the fine fiducial line and locations of fine measurement markings of the fine scale.

10 . The micrometer head displacement system of claim 9 , wherein the one or more processors are configured to execute an edge tool to determine the location of the fine fiducial line and the locations of the fine measurement markings of the fine scale.

11 . The micrometer head displacement system of claim 1 , wherein the determining the coarse measurement includes:

using image recognition on the coarse scale to identify a zero marking;

scanning from left to right, using edge detection algorithms, to count a number of coarse measurement markings until reaching the coarse fiducial line; and

determining the coarse measurement based on the counted number of coarse measurement markings.

12 . The micrometer head displacement system of claim 1 , wherein the positive indication is configured to be provided for confirming the proper positioning when the fine fiducial line is approximately positioned at a center of a field of view of the imaging portion and a substantially equal number of fine measurement markings appear on either side of the fine fiducial line.

13 . A method of operating a micrometer head displacement system, comprising:

controlling an imaging portion of the micrometer head displacement system comprising at least one camera to acquire at least one image of a micrometer head, wherein the micrometer head includes a coarse scale and a coarse fiducial line configured to move relative to one another for indicating a coarse scale measurement, and a fine scale and a fine fiducial line configured to move relative to one another for indicating a fine scale measurement;

displaying a positive indication on a screen to indicate proper positioning of the imaging portion relative to the micrometer head;

determining a coarse measurement based at least in part on the at least one image, wherein the coarse measurement corresponds to a coarse relative position between the coarse scale and the coarse fiducial line;

determining a fine measurement based at least in part on the at least one image and based on calculating an interpolated position of the fine fiducial line, wherein the fine measurement corresponds to a fine relative position between the fine scale and the fine fiducial line; and

determining a micrometer head displacement based at least in part on summing the coarse measurement with the fine measurement.

14 . The method of claim 13 , comprising:

displaying the micrometer head displacement on a screen.

15 . The method of claim 13 , comprising:

displaying the at least one image of the micrometer head on a screen.

16 . The method of claim 13 , comprising:

utilizing a contrast curve analysis on the at least one image of the micrometer head to determine a location of the fine fiducial line and locations of fine measurement markings of the fine scale.

17 . The method of claim 16 , wherein the utilizing of the contrast curve analysis comprises:

utilizing contrast curve analysis for determining two edge locations for the fine fiducial line, wherein the location of the fine fiducial line is determined according to at least one of a middle or average between the two edge locations of the fine fiducial line;

utilizing contrast curve analysis for determining two edge locations for the first fine measurement marking, wherein the location of the first fine measurement marking is determined according to at least one of a middle or average between the two edge locations of the first fine measurement marking; and

utilizing contrast curve analysis for determining two edge locations for the second fine measurement marking, wherein the location of the second fine measurement marking is determined according to at least one of a middle or average between the two edge locations of the second fine measurement marking.

18 . The method of claim 13 , comprising:

on the fine scale, determining a first fine measurement marking which is closest and does not exceed the fine fiducial line, and determining a first fine measurement based on the first fine measurement marking;

determining a position of the fine fiducial line within a first distance between the first fine measurement marking and a second fine measurement marking, which is adjacent to the first fine measurement marking wherein the position of the fine fiducial line lies between the first and second fine measurement markings;

determining a ratio between a second distance from the first fine measurement marking to the position of the fine fiducial line and the first distance from the first fine measurement marking to the second fine measurement marking, and calculating the interpolated position of the fine fiducial line based on the ratio; and

determining the fine measurement by summing the first fine measurement with an interpolated fine measurement which is based on the interpolated position of the fine fiducial line.

19 . The method of claim 13 , comprising:

using image recognition on the coarse scale to identify a zero marking;

scanning from left to right, using edge detection algorithms, to count a number of coarse measurement markings until reaching the coarse fiducial line; and

determining the coarse measurement based on the counted number of coarse measurement markings.

Assignments (1)

Continuity (1)

References Cited (25)