LASER PROJECTION SYSTEM AND METHOD

• US 20170161889A1
• Filed: 02/14/2017
• Published: 06/08/2017
• Est. Priority Date: 03/22/2012
• Status: Active Grant

• Current Assignee: Virtek Vision International Inc. (Gerber Scientific LLC)
• Original Assignee: Virtek Vision International Inc. (Gerber Scientific LLC)
• Inventors: Rueb, Kurt D.
• Granted Patent: US 10,157,458 B2
• Time in Patent Office: Days
• CPC Class Codes: B23Q 17/2423 by projecting crossing light beams
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01B 11/005 coordinate measuring machines
• CPC Class Codes: G01B 11/2545 with one projection direction and several detection directions, e.g. stereo
• CPC Class Codes: G01C 11/00 Photogrammetry or videogrammetry, e.g. stereogrammetry; Photographic surveying
• CPC Class Codes: G01C 11/02 Picture taking arrangements specially adapted for photogrammetry or photographic surveying, e.g. controlling overlapping of pictures
• CPC Class Codes: G01C 11/025 by scanning the object
• CPC Class Codes: G01C 11/08 the pictures not being supported in the same relative position as when they were taken
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G06T 2207/10012 Stereo images
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/20224 Image subtraction
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 2207/30204 Marker
• CPC Class Codes: G06T 7/0006 using a design-rule based approach
• CPC Class Codes: G06T 7/001 using an image reference approach
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06T 7/194 involving foreground-background segmentation
• CPC Class Codes: G06T 7/74 involving reference images or patches
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/254 : in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 23/00 : Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: H04N 9/3129 : scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161

Abstract

A laser projection system for projecting an image on a workpiece includes a photogrammetry assembly and a laser projector, each communicating with a computer. The photogrammetry assembly includes a first camera for scanning the workpiece, and the laser projector projects a laser image to arbitrary locations. Light is conveyed from the direction of the workpiece to the photogrammetry assembly. The photogrammetry assembly signals the coordinates light conveyed toward the photogrammetry assembly to the computer with the computer being programmable for determining a geometric location of the laser image. The computer establishes a geometric correlation between the photogrammetry assembly, the laser projector, and the workpiece for realigning the laser image to a corrected geometric location relative to the workpiece.

Claims

1. A laser projection system comprising:

a laser projector configured to project a laser image onto a workpiece;

an optical sensor assembly configured to periodically emit light toward the workpiece and optically detect the location of a plurality of reference targets thereon; and

a computer electrically coupled to the laser projector and the optical sensor assembly, the computer being configured to perform the following method steps;

calculate the location of the workpiece within a geometric coordinate system based on the location of the plurality of reference targets as detected by the optical sensor assembly,

cause the laser projector to project a template onto a desired geometric location of the workpiece for a manufacturing operation,

monitor for relative movement between the workpiece, the laser projector, and the optical sensor assembly,

correct the template being projected onto the workpiece.

2. The laser projection system of claim 1 wherein the geometric coordinate system is a three-dimensional coordinate system.

3. The laser projection system of claim 1 wherein the optical sensor assembly comprises a photogrammetry assembly including first and second cameras that are spaced apart from each other by a fixed distance.

4. The laser projection system of claim 1 wherein the emitted light includes a wavelength of between 520 nm and 540 nm.

5. The laser projection system of claim 1 wherein the computer is further adapted to determine a geometric correlation between the optical sensor assembly and the laser projector.

6. The laser projection system of claim 1 wherein the plurality of targets includes encoded retroreflective targets.

7. The laser projection system of claim 1 wherein the template is a manufacturing template for performing a weld operation or a machine operation on the workpiece.

8. A method for projecting an image onto a workpiece comprising:

providing a laser projector configured to project a laser image onto the workpiece;

periodically emitting light toward the workpiece for detection by an optical sensor assembly;

using the optical sensor assembly for optically detecting the location of a plurality of reference targets supported on the workpiece;

calculating the location of the workpiece within a geometric coordinate system based on the location of the plurality of reference targets;

causing the laser projector to project a template onto a desired geometric location of the workpiece for a manufacturing operation;

monitoring for relative movement between the workpiece, the laser projector, and the optical sensor assembly; and

correcting the template being projected onto the workpiece based upon movement of the .

9. The method set forth in claim 8 further including determining a geometric correlation between the optical sensor assembly and the laser projector.

10. The method set forth in claim 8 wherein the geometric coordinate system is a three-dimensional coordinate system.

11. The method set forth in claim 8 wherein the optical sensor assembly includes a photogrammetry assembly comprising first and second cameras that are spaced apart from each other by a fixed distance.

12. The method set forth in claim 8 wherein the emitted light includes a wavelength of between 520 nm and 540 nm.

13. The method set forth in claim 8 wherein the plurality of targets includes encoded retroreflective targets.

14. The method set forth in claim 8 wherein emitting light toward the workpiece includes scanning a space comprising the workpiece for establishing a background image and wherein optically detecting the location of the plurality of encoded retroreflective targets includes subtracting the background image from light reflected by the plurality of encoded retroreflective targets.

15. The method set forth in claim 8 wherein the template is a manufacturing template for performing a weld operation or a machine operation on the workpiece.