NON-CONTACT MEASUREMENT DEVICE

• US 20140192187A1
• Filed: 01/08/2014
• Published: 07/10/2014
• Est. Priority Date: 01/08/2013
• Status: Abandoned Application

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Atwell, Paul C., York, Frederick John, Briggs, Clark H.
• Application Number:
  US14/149,888
• Publication Number:
  US 20140192187A1
• Time in Patent Office: Days
• US Class Current: 348/136
• CPC Class Codes: G01B 11/03 by measuring coordinates of points
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50

Abstract

A portable coordinate measuring machine for measuring the coordinates of an object in space is provided including a manually positionable articulated arm portion having a plurality of connected arm segments that include position transducers that provide position signals. A probe assembly connected to an arm segment includes a non-contact measurement device having a projector and a camera separated by a baseline distance. The projector includes a light source that emits a line of light. The camera includes an image sensor having an array of pixels that receives the light reflected from the object in a sensor plane. A first processor of the camera, coupled to the image sensor, determines centroids from the received light. A second processor coupled to the first processor determines three-dimensional coordinates of points on the object based at least in part on the centroids provided by the processor, the positions, and the baseline distance.

Claims

1. A portable coordinate measuring machine for measuring three-dimensional coordinates of an object in space, the coordinate measuring machine comprising:

a manually positionable articulated arm portion having opposed first and second ends, the arm portion including a plurality of connected arm segments, each arm segment including at least one position transducer for producing a position signal;

a base section connected to the second end;

a probe assembly connected to the first end, the probe assembly including;

a housing;

a first processor disposed within the housing;

a projector disposed within the housing, the projector having a light source configured to emit a first light onto a surface of the object, wherein the projector is configured to project the first light to form a line on a plane arranged perpendicular to the direction of propagation of the first light;

a camera arranged within the housing, the camera including a lens and an image sensor, the image sensor having an array of pixels on a sensor plane, the lens configured to receive a second light and to image the second light onto the image sensor, the second light being a reflection of the first light from the surface, the image sensor further configured to send a first electrical signal to the first processor in response to receiving the second light, the first processor coupled to the image sensor and configured to determine a plurality of centroids based at least in part on the first electrical signal, there being a baseline distance between the projector and the camera; and

a second processor, external to the housing, configured to receive the position signals from the transducers and to receive the plurality of centroids from the first processor, the second processor further configured to determine and store, or transmit to an external device, the three-dimensional coordinates a plurality of points on the surface, the three-dimensional coordinates based at least part on the position signals, the received centroid data, and the baseline distance.

2. The portable coordinate measuring machine according to claim 1, wherein the projector includes a pattern generator positioned adjacent the light source such that the light emitted by the light source is directed through the pattern generator.

3. A method of determining three-dimensional coordinates of points on a surface on an object, the method comprising:

providing a device that includes a manually positionable articulated arm portion, a base section, a probe assembly, and a second processor, the arm portion having opposed first and second ends, the arm portion including a plurality of connected arm segments, each arm segment including at least one position transducer for producing a position signal, the base section connected to the second end, the probe assembly connected to the first end, the probe assembly including a housing, a first processor, a projector, and a camera, the projector disposed within the housing, the projector having a light source configured to emit a first light on the surface of the object, the projector being configured to project the first light to form a line on a plane arranged perpendicular to the direction of propagation of the first light, the camera arranged within the housing, the camera including a lens and an image sensor, the image sensor having an array of pixels on a sensor plane, the first processor coupled to the image sensor, there being a baseline distance between the projector and the camera, the second processor external to the housing;

emitting from the projector the first light onto the surface;

receiving with the lens a second light, the second light being a reflection of the first light from the surface;

imaging with the lens the second light onto the sensor plane and, in response, sending a first electrical signal to the first processor;

determining with the first processor a plurality of centroids of the points on the surface, the plurality of centroids based at least in part on the first electrical signal;

receiving with the second processor the plurality of centroids;

determining with the second processor the three-dimensional coordinates of the points on the surface based at least in part on the position signals, the plurality of centroids, and the baseline distance; and

storing the three-dimensional coordinates of the points on the surface.

4. The method according to claim 3 wherein, in the step of determining with the second processor the three-dimensional coordinates of the points on the surface, the first processor calculates a centroid for each column of pixels.

5. The method according to claim 4 wherein, in the step of providing a device, the first processor is operably coupled to the second processor via a communication bus.

6. The method according to claim 5, further comprising communicating the three-dimensional coordinates to an external device.