Portable three-dimensional metrology with data displayed on the measured surface

Abstract

A portable instrument for 3D surface metrology projects augmented-reality feedback directly on the measured target surface. The instrument generates structured-light measuring-patterns and projects them successively on a target surface. Features, contours, and textures of the target surface distort each projected measuring-pattern image (MPI) from the original measuring-pattern. The instrument photographs each MPI, extracts measurement data from the detected distortions, and derives a result-image from selected aspects of the measurement data. The instrument warps the result-image to compensate for distortions from the projector or surface and projects the result-image on the measured surface, optionally with other information such as summaries, instrument status, menus, and instructions. The instrument is lightweight and rugged. Accurate measurements with hand-held embodiments are made possible by high measurement speed and an optional built-in inertial measurement unit to correct for pose and motion effects.

What is claimed is: 
     
         1 . An apparatus for measuring a surface, the apparatus comprising:
 a portable housing,   a projection assembly mounted in the portable housing and projecting an image on the surface,   a camera mounted in the portable housing and configured to capture the projected image as measurement data, and   a processor controlling the projection assembly and the camera and receiving the measurement data from the camera, where
 the projection assembly comprises an image generator, a light source, and a train of projection optics, 
 the projected image comprises a measurement-pattern image or a result image, and 
 the processor derives a characteristic of the result-image by analyzing the measurement data corresponding to the measurement-pattern image. 
   
     
     
         2 . The apparatus of  claim 1 , where the portable housing comprises at least one of a handle, a monopod, and a spacer. 
     
     
         3 . The apparatus of  claim 1 , further comprising a portable power source mounted in the portable housing. 
     
     
         4 . The apparatus of  claim 1 , where the processor comprises an on-board processor component mounted in the portable housing. 
     
     
         5 . The apparatus of  claim 1 , where the image generator comprises one of a liquid-crystal array and a microelectromechanical system. 
     
     
         6 . The apparatus of  claim 1 , where the light source has a variable spectrum controlled by the processor and comprises a light-emitting diode. 
     
     
         7 . The apparatus of  claim 1 , where at least one of the light source, image generator, and train of projection optics are instrumental in projecting both the measurement-pattern image and the result-image. 
     
     
         8 . The apparatus of  claim 1 , further comprising an auxiliary light source having a wavelength outside the visible spectrum. 
     
     
         9 . The apparatus of  claim 8 , further comprising at least one of an auxiliary image generator compatible with the auxiliary light source and an auxiliary train of projection optics compatible with the auxiliary light source. 
     
     
         10 . The apparatus of  claim 1 , where the camera is configured to exclude ambient light that would otherwise cause errors in the measurement data. 
     
     
         11 . The apparatus of  claim 1 , further comprising an inertial measurement unit mounted in the portable housing and configured to transmit pose and motion data to the processor. 
     
     
         12 . A method for measuring a surface, the method comprising:
 positioning a portable metrology instrument relative to the surface,   projecting a measurement-pattern image from the portable metrology instrument onto the surface,   capturing as measurement data a captured image of the measurement-pattern image projected on the surface,   creating a point cloud representing the surface, in which a point in the point cloud model is based on comparing a point in the measurement data with a corresponding point in a stored version of the measurement-pattern image,   creating a result-image from the point cloud and from stored information,   transforming the result-image into coordinates matched to projection conditions on the surface, and   projecting the result-image onto the surface from the portable metrology instrument.   
     
     
         13 . The method of  claim 12 , where the result-image is projected within 0.1 second after the measurement image. 
     
     
         14 . The method of  claim 12 , where the result-image comprises at least one of a false-color representation of the measurement, a summary of results of the measurement, a symbol dependent on the measurement, an alphanumeric character, a navigational symbol, a status indicator, a menu, and an instruction. 
     
     
         15 . The method of  claim 12 , further comprising monitoring the pose and motion of the portable metrology instrument and doing at least one of:
 issuing a warning if the portable metrology instrument moved in excess of a predetermined threshold during the projecting and capturing of the measurement-pattern image,   storing the location and orientation of an area of the surface being measured,   adjusting the point cloud to compensate for the pose and motion of the portable metrology instrument during the projecting and capturing of the measurement-pattern image, and   adapting a feature location and orientation in the result-image to compensate for the pose and motion of the portable metrology instrument during the projecting of the result-image.   
     
     
         16 . The method of  claim 12 , further comprising recording the result-image as projected on the surface. 
     
     
         17 . The method of  claim 12 , further comprising adjusting at least one of color, brightness, and feature position in the result-image to optimize visibility or legibility of the result-image, where the adjusting is partially responsive to a characteristic of the measurement data. 
     
     
         18 . A non-transitory machine-readable storage medium programmed with data and instructions, the data and instructions comprising:
 reference data,   user-interface display data, and instructions for   generating a structured-light pattern,   projecting the structured-light pattern on a surface to produce a measurement-pattern image,   capturing the measurement-pattern image as measurement data,   recording a pose-and-motion history affecting the measurement data,   analyzing the measurement data with the reference data and the pose-and-motion history to produce a measurement result,   generating a result-image from the measurement result and the user-interface display data,   transforming the result-image into surface-projection coordinates to produce a corrected result-image, and   projecting the corrected result-image onto the surface.   
     
     
         19 . (canceled) 
     
     
         20 . (canceled)