Optical pattern projector

Abstract

An optical pattern projector used for projecting a structured-light pattern onto an object for dimensioning is presented. The optical pattern projector utilizes a laser array, a lenslet array, a lens, and a diffractive optical element to create a repeated pattern of projected dots. The pattern repetition is based on the grid pattern of laser array. Each laser's collimated beam, when projected through the lens, impinges on the diffractive optical element from a slightly different direction. The diffractive optical element creates a sub-patterns that continue propagating along these different directions and combine on a target to produce a repeating optical pattern.

1 . An optical pattern projector, comprising:
 a laser array, having a plurality of lasers equally spaced in a grid pattern and configured to radiate light in the same direction;   a lenslet array having a plurality of lenslets arranged so that each lenslet is aligned with a particular laser, the lenslet array positioned in front of the laser array to focus the radiated light from the lasers into a plurality of collimated laser beams;   a lens positioned in front of the lenslet array and sufficiently large to receive all of the laser beams, the lens redirecting each laser beam along a particular incident angle determined by the spatial position of the particular laser beam in the grid pattern; and   a diffractive optical element (DOE) positioned in front of the lens to receive all of the laser beams and, for each laser beam, to (i) create a sub-pattern and (ii) project each laser beam's sub-pattern towards a target along a particular angle determined by the particular laser beam's incident angle, wherein the sub-patterns from each laser beam combine on the target to form an optical pattern.   
     
     
         2 . The optical pattern projector according to  claim 1 , wherein the laser array is an array of vertical cavity surface emitting lasers (VCSELs). 
     
     
         3 . The optical pattern projector according to  claim 2 , wherein the laser array comprises more than 100 VCSELs. 
     
     
         4 . The optical pattern projector according to  claim 1 , wherein the lens is an f-theta lens. 
     
     
         5 . The optical pattern projector according to  claim 1 , wherein the sub-patterns from the laser beams are identical. 
     
     
         6 . The optical pattern projector according to  claim 1 , wherein the optical pattern comprises the sub-patterns arranged according to the grid pattern. 
     
     
         7 . The optical pattern generator according to  claim 1 , wherein the sub-pattern comprises a non-uniform pattern of light spots. 
     
     
         8 . The optical pattern generator according to  claim 1 , wherein the sub-pattern comprises 3-15 light spots. 
     
     
         9 . The optical pattern generator according to  claim 1 , wherein the light radiated is infrared light. 
     
     
         10 . The optical pattern projector according to  claim 1 , wherein the lenslets comprise more than one optical element. 
     
     
         11 . A structured-light dimensioning system, comprising:
 an optical pattern projector for projecting a structured-light pattern onto an object for dimensioning, wherein the optical pattern projector comprises:
 a laser array, having a plurality of lasers equally spaced in a grid pattern and configured to radiate light in the same direction, 
 a lenslet array having a plurality of lenslets arranged so that each lenslet is aligned with a particular laser, the lenslet array positioned in front of the laser array to focus the radiated light from the lasers into a plurality of collimated laser beams, 
 a lens positioned in front of the lenslet array and sufficiently large to receive all of the laser beams, the lens redirecting each laser beam along a particular incident angle determined by the spatial position of the particular laser beam in the grid pattern, and 
 a diffractive optical element (DOE) positioned in front of the lens to receive all of the laser beams and for each laser beam to (i) create a sub-pattern and (ii) project each laser beam's sub-pattern towards the object along a particular angle determined by the particular laser beam's incident angle; 
   a imaging subsystem for capturing images of the structured-light pattern transmitted by the optical pattern projector and reflected from the object; and   a range mapping subsystem comprising a processor communicatively coupled to the imaging subsystem and configured to:
 (i) receive a captured image, 
 (ii) evaluate the structured-light pattern in the captured image, 
 (iii) obtain, from the evaluation, the range of each pixel in the captured image, and 
 (iv) determine, using the range for each pixel, the dimensions of the object. 
   
     
     
         12 . The structured-light dimensioning system according to  claim 11 , wherein the structured-light dimensioning system is handheld. 
     
     
         13 . The structured-light dimensioning system according to  claim 11 , wherein the lens is an f-theta lens. 
     
     
         14 . The structured-light dimensioning system according to  claim 11 , wherein the structured-light pattern comprises the sub-patterns arranged according to a square grid. 
     
     
         15 . The structured-light dimensioning system according to  claim 14 , wherein the sub-patterns are not overlapping. 
     
     
         15 . (canceled) 
     
     
         16 . The structured-light dimensioning system according to  claim 11 , wherein the radiated light is infrared light. 
     
     
         17 . The structured-light dimensioning system according to  claim 11 , wherein the laser array is an array of vertical cavity surface emitting lasers (VCSELs). 
     
     
         18 . The structured-light dimensioning system according to  claim 11 , wherein the lenslets comprise more than one optical element. 
     
     
         19 . A method for creating a repeating optical pattern, the method comprising:
 projecting light from a laser array comprising a square grid of co-directed lasers;   collimating the light from each laser with a lenslet in a lenslet array to form a set of co-directed laser beams arranged according to the square grid;   focusing the light from each laser beam onto a diffractive optical element (DOE) using an f-Theta lens, each laser beam focused at a particular incident angle determined by the laser beam's position in the square grid; and   diffracting, using the DOE, the light from each laser beam to form a sub-pattern, wherein each laser beam's sub-pattern propagates along a particular angle determined by the particular laser beam's incident angle so that the sub-patterns form a repeating optical pattern.   
     
     
         20 . The method according to  claim 19 , wherein the repeating optical pattern comprises sub-patterns arranged according to a square grid.