System and Method for Recalibrating a Projector System

Abstract

The invention is directed to a system and method for recalibrating a projector system. The projector may be calibrated using one or more cameras arranged near or adjacent to a projector of a projector system. The one or more cameras may be calibrated once and made mechanically stable so that they do not move relative to each other. During operation of the projector system, the projector may project one or more specific patterns onto a work surface, where the one or more cameras capture each of the projected patterns. All the captured images of the patterns by the one or more cameras may be used to determine projector calibration parameters in order to recalibrate the projector.

What is claimed is: 
     
         1 . A recalibratable projector system, comprising:
 one or more cameras;   a projector; and   at least one processor configured to execute stored instructions to:
 project one or more patterns on to a work surface via the projector, 
 capture images of the projected one or more patterns via the one or more cameras, 
 perform analysis on the captured images of the one or more patterns, 
 determine projector calibration parameters based at least in part on the performed analysis on the images, and 
 recalibrate the projector system such that an image is projected onto the work surface by the projector at a correct position based on the determined projector calibration parameters. 
   
     
     
         2 . The recalibratable projector system of  claim 1 , further comprising one or more of the following: (ii) at least one laser scanner and (ii) at least one surface profiling sensor, wherein the one or more cameras, the at least one scanner, the at least one surface profiling sensor, and the projector are configured to profile the work surface. 
     
     
         3 . The recalibratable projector system of  claim 1 , wherein the one or more cameras are mechanically affixed to the projector system and calibrated relative to each other and relative to the projector. 
     
     
         4 . The recalibratable projector system of  claim 3 , wherein the calibration of the one or more cameras is performed only once and is a known parameter. 
     
     
         5 . The recalibratable projector system of  claim 3 , wherein the one or more cameras are mechanically affixed to the projector system via one or more of the following: (i) a screw, (ii) a fastener, and (ii) an adhesive. 
     
     
         6 . The recalibratable projector system of  claim 1 , wherein the one or more patterns includes specific geometric shapes. 
     
     
         7 . The recalibratable projector system of  claim 1 , wherein the at least one processor is further configured to profile the work surface, and wherein the profiling of the work surface and recalibration of the projector system are performed simultaneously. 
     
     
         8 . The recalibratable projector system of  claim 1 , wherein the determination of the projector calibration parameters includes calculating correspondences between points from the one or more cameras and the projector. 
     
     
         9 . The recalibratable projector system of  claim 1 , wherein the determination of the projector calibration parameters includes solving at least one equation system for unknown parameters. 
     
     
         10 . The recalibratable projector system of  claim 9 , wherein the at least one equation system is solved based on a Levenberg-Marquardt algorithm. 
     
     
         11 . The recalibratable projector system of  claim 9 , wherein the determination of the projector calibration parameters includes obtaining intrinsic and extrinsic parameters. 
     
     
         12 . The recalibratable projector system of  claim 11 , wherein the intrinsic parameters includes one or more of the following: (i) projector focal lengths in an x-direction and a y-direction, (ii) principal point in the x-direction and the y-direction, and (iii) skew coefficient between an x-axis and a y-axis. 
     
     
         13 . The recalibratable projector system of  claim 11 , wherein the extrinsic parameters includes one or more of the following: (i) translation vector between the projector and the one or more cameras and (ii) rotation matrix between the projector and the one or more cameras. 
     
     
         14 . The recalibratable projector system of  claim 1 , wherein the one or more patterns includes the image itself. 
     
     
         15 . The recalibratable projector system of  claim 1 , wherein the one or more cameras includes an infrared camera. 
     
     
         16 . The recalibratable projector system of  claim 1 , wherein the image is a blueprint of a construction-related task. 
     
     
         17 . The recalibratable projector system of  claim 1 , wherein the projector is a position enabled projector. 
     
     
         18 . A method for recalibrating a projector system, the method comprising the steps of:
 projecting, by at least one processor, one or more patterns on to a work surface via a projector;   capturing, by the at least one processor, images of the projected one or more patterns via one or more cameras;   performing, by the at least one processor, analysis on the captured images of the one or more patterns;   determining, by the at least one processor, projector calibration parameters based at least in part on the performed analysis on the images;   recalibrating, by the at least one processor, the projector system such that an image is projected onto the work surface by the projector at a correct position based on the determined projector calibration parameters; and   using the projected, recalibrated image in a construction task.   
     
     
         19 . A non-transitory computer-readable medium comprising a set of executable instructions, the set of executable instructions when executed by at least one processor causes the at least one processor to perform a method for recalibrating a projector system, the method comprising the steps of:
 projecting one or more patterns on to a work surface via a projector;   capturing images of the projected one or more patterns via one or more cameras;   performing analysis on the captured images of the one or more patterns;   determining projector calibration parameters based at least in part on the performed analysis on the images; and   recalibrating the projector system such that an image is projected onto the work surface by the projector at a correct position based on the determined projector calibration parameters.