Three-dimensional measurement device

Abstract

A scanner capable of determining 3D coordinates in the presence of bright background light includes a laser and a camera, the laser emitting light at a wavelength adjusted with a thermoelectric cooler, the camera passing the adjusted wavelength through a bandpass filter.

What is claimed is: 
     
         1 . An apparatus comprising:
 a projector having a laser source coupled to a thermoelectric cooler, the thermoelectric cooler operable to keep light emitted from the laser source at a fixed wavelength, the projector operable to project a pattern of light onto an object;   a first camera having a first optical filter with a first passband, the first optical filter operable to pass a limited range of wavelengths through the first passband, the first camera further operable to capture a first image of the projected pattern of light on the object; and   a processor coupled to the projector and the first camera, the processor operable to determine three-dimensional (3D) coordinates of the object based at least in part on the projected pattern of light and the captured first image.   
     
     
         2 . The apparatus of  claim 1 , further comprising:
 a temperature sensor coupled to the laser source; and   a control circuit operable to receive a signal from the temperature sensor and, in response, to send a control signal to the thermoelectric cooler.   
     
     
         3 . The apparatus of  claim 1 , wherein the first optical filter is operable to block sunlight outside the first passband of the first optical filter. 
     
     
         4 . The apparatus of  claim 1 , wherein the first optical filter comprises a glass filter placed in front of other elements of the first camera. 
     
     
         5 . The apparatus of  claim 4 , wherein the glass filter comprises a glass window having a multi-layer dielectric coating. 
     
     
         6 . The apparatus of  claim 1 , further comprising:
 a second camera having a second optical filter with a second passband, the second optical filter operable to pass the fixed wavelength through the second passband, the second camera further operable to capture a second image of the projected pattern of light on the object, the processor being operable to determine the 3D coordinates of the object further based on the captured second image.   
     
     
         7 . The apparatus of  claim 2 , further comprising:
 an enclosure that houses the projector and the first camera, the enclosure coupled to a heat sink, a first side of the heat sink being thermally coupled to the laser source and a second side of the heat sink being thermally coupled to air outside the enclosure.   
     
     
         8 . The apparatus of  claim 2 , further comprising:
 a rigid carrying structure having the first camera, the projector, and a structural element connecting the first camera and the projector; and   an enclosure surrounding the carrying structure, the carrying structure being lightly coupled to the enclosure.   
     
     
         9 . The apparatus of  claim 8 , wherein the structural element that separates the first camera and the projector further provides thermal isolation of the laser source and its coupled temperature sensor from heat sources near the first camera. 
     
     
         10 . A method comprising:
 with a laser source coupled to a thermoelectric cooler, generating a beam of light at a fixed wavelength;   with a projector coupled to the laser source, converting the beam of light into a pattern of light and projecting the pattern of light onto an object;   with a first camera, capturing a first image of the pattern of light on the object, the first camera including a first optical filter having a first passband;   with a processor coupled to the projector and the first camera, determining three-dimensional (3D) coordinates of the object based at least in part on the projected pattern of light and the captured first image; and   storing the 3D coordinates.   
     
     
         11 . The method of  claim 10 , further comprising:
 with a control circuit, receiving a signal from a temperature sensor and, in response, sending a control signal to the thermoelectric cooler.   
     
     
         12 . The method of  claim 10 , further comprising blocking sunlight outside the first passband of the first optical filter. 
     
     
         13 . The method of  claim 10 , further comprising sending light through a glass filter in the first camera, the glass filter including a glass window having a multi-layer dielectric coating. 
     
     
         14 . The method of  claim 10 , further comprising:
 with a second camera, capturing a second image of the projected pattern of light on the object, the second camera including a second optical filter having a second passband, the processor being operable to determine the 3D coordinates of the object further based on the captured second image.   
     
     
         15 . An apparatus comprising:
 a projector configured to project a patter of light onto an object, the projector having a laser source thermally coupled to a thermoelectric cooler, the thermoelectric cooler cooperating with the laser source to emit light at a predetermined wavelength;   a first camera having a first optical filter with a first passband, the first optical filter operable to pass a limited range of wavelengths through the first passband, the first camera further operable to capture a first image of the projected pattern of light on the object; and   a processor coupled to the projector and the first camera, the processor operable to determine three-dimensional (3D) coordinates of the object based at least in part on the projected pattern of light and the captured first image.   
     
     
         16 . The apparatus of  claim 15 , further comprising:
 a temperature sensor coupled to the laser source; and   a control circuit operably coupled to the temperature sensor and transmitting a control signal to the thermoelectric cooler.   
     
     
         17 . The apparatus of  claim 15 , wherein the first optical filter is operable to block sunlight outside the first passband of the first optical filter. 
     
     
         18 . The apparatus of  claim 15 , wherein the first optical filter comprises a glass filter placed in front of other elements of the first camera. 
     
     
         19 . The apparatus of  claim 15 , wherein the glass filter comprises a glass window having a multi-layer dielectric coating. 
     
     
         20 . The apparatus of  claim 15 , further comprising a second camera having a second optical filter with a second passband, the second optical filter operable to pass the fixed wavelength through the second passband, the second camera further operable to capture a second image of the projected pattern of light on the object, the processor being operable to determine the 3D coordinates of the object further based on the captured second image.