# US 10,480,929 B2 · Method and apparatus for following an operator and locking onto a retroreflector with a laser tracker

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- Number: US 10,480,929 B2
- Document ID: US10480929B2
- Status: Granted
- Kind: B2
- Application number: 16/239,967
- Filed: 2019-01-04
- Published: 2019-05-09
- Granted: 2019-11-19
- Earliest claimed: 2010-04-21
- Assignees: Faro Technologies, Inc.
- Applicants: FARO Technologies, Inc.
- Inventors: Kalyan Nagalla; Robert C. Mehler; Robert E. Bridges
- Web page: https://patentgrep.com/patent/US10480929B2

## CPC

- G01B 11/002: {for measuring two or more coordinates}
- G01B 5/004: for measuring coordinates of points
- G01B 21/047: {Accessories, e.g. for positioning, for tool-setting, for measuring probes}
- G01C 15/002: {Active optical surveying means (optical plumbing G01C15/105)}
- G01S 3/786: the desired condition being maintained automatically
- G01S 17/06: Systems determining position data of a target
- G01S 17/66: Tracking systems using electromagnetic waves other than radio waves
- G01S 17/86: Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
- G06F 3/017: {Gesture based interaction, e.g. based on a set of recognized hand gestures (interaction based on gestures traced on a digitiser G06F3/04883)}
- G06F 3/0304: {Detection arrangements using opto-electronic means (constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042)}
- G06F 3/0346: with detection of the device orientation or free movement in a three-dimensional [3D] space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors
- G06F 3/0421: {by interrupting or reflecting a light beam, e.g. optical touch-screen}
- G06F 3/0425: {using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected (tracking a projected light spot to determine a position on a display surface G06F3/0386)}
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A method for optically communicating, from a user to a laser tracker, a command to direct a beam of light from the laser tracker to a retroreflector with steps including: projecting a first light from a light source disposed on the laser tracker to the retroreflector; reflecting a second light from the retroreflector, the second light being a portion of the first light; obtaining first sensed data by sensing a third light, the third light being a portion of the second light, wherein the first sensed data is obtained by imaging the third light onto a photosensitive array disposed on the laser tracker and converting the third light on the photosensitive array into digital form; generating by the user, between a first time and a second time, a predefined temporal pattern, the predefined temporal pattern including at least a decrease in optical power of the third light followed by an increase in the optical power of the third light, the predefined temporal pattern corresponding to the command; determining by the laser tracker that the first sensed data corresponds to the predefined temporal pattern; and, pointing the beam of light from the laser tracker to the retroreflector.

## Claims

### Claim 1

A method for optically communicating, from a user to a laser tracker, a command to direct a beam of light from the laser tracker to a retroreflector with steps comprising:
projecting a first light from a light source disposed on the laser tracker to the retroreflector;
reflecting a second light from the retroreflector, the second light being a portion of the first light;
obtaining first sensed data by sensing a third light, the third light being a portion of the second light, wherein the first sensed data is obtained by imaging the third light onto a photosensitive array disposed on the laser tracker and converting the third light on the photosensitive array into digital form;
generating by the user, between a first time and a second time, a predefined temporal pattern, the predefined temporal pattern including at least a decrease in optical power of the third light followed by an increase in the optical power of the third light, the predefined temporal pattern corresponding to the command;
determining by the laser tracker that the first sensed data corresponds to the predefined temporal pattern; and
pointing the beam of light from the laser tracker to the retroreflector.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
subsequent to pointing the beam of light from the laser tracker to the retroreflector, locking onto the retroreflector with the beam of light from the laser tracker.

### Claim 3 (depends on 1)

The method of claim 1, wherein:
the generating by the user a predetermined temporal pattern comprises, a decrease followed by an increase in optical power of the first light.

### Claim 4 (depends on 3)

The method of claim 3, wherein:
the decrease followed by the increase in optical power of the first light comprises a plurality of a decrease followed by an increase in optical power of the first light in rapid succession.

### Claim 5 (depends on 4)

The method of claim 4, wherein:
the rapid succession comprises four times in rapid succession that is representative of a four finger salute.

### Claim 6 (depends on 1)

A laser tracker system, comprising:
a retroreflector;
a laser tracker comprising:
a light source;
a photosensitive array; and
a processor responsive to executable instructions which when executed by the processor is operable to facilitate the method of claim 1.

### Claim 7 (depends on 2, 6)

The laser tracker system of claim 6, wherein:
the processor is further responsive to the executable instructions to facilitate the method of claim 2.