Handheld three dimensional scanner with autofocus or autoaperture

Abstract

A three-dimension scanning apparatus and method of use is disclosed. The scanner includes a first camera and a processor. The first camera has an adjustable focus distance and is placed at a first distance from a first object to obtain an image of the first object. The processor adjust the focus distance of the first camera to a first focus distance that forms an image of the first object at an image plane of the first camera. Additionally, the apparatus includes a light intensity meter for measuring a level of light intensity at the first camera. The first camera includes an adjustable aperture. The processor adjusts the aperture of the first camera automatically based on the measured light level.

1 . A method for scanning an object with a three-dimensional (3D) scanner, comprising:
 placing a first camera of the 3D scanner at a first distance from a first object, the first camera having an adjustable focus;   adjusting, via a processor, a focus distance of the first camera to a first focus distance to form an image at an image plane of the first camera of the   scanning the first object using the first focus distance of the first camera.   
     
     
         2 . The method of  claim 1 , wherein the first camera is at a second distance from a second object, further comprising:
 adjusting the focus distance of the first camera to a second focus distance to form an image at the image plane of the first camera of the second object; and   scanning the second object using a second focus distance of the first camera.   
     
     
         3 . The method of  claim 1 , wherein adjusting the current focus distance to the first focus distance further comprises at least one of: (i) obtaining a distance measurement between the first camera and the first object; and (ii) determining the first focus distance as the focus distance at which a sharpness of an image of the first object reaches a substantial maximum. 
     
     
         4 . The method of  claim 1 , wherein a difference between a current focus distance and the first focus distance is greater than a selected threshold, the method further comprising dividing a range of focus distances of the first camera into a preselected number of sub-ranges and adjusting the focus distance to step through the preselected number of sub-ranges to determine a sub-range that includes the first focus distance. 
     
     
         5 . The method of  claim 1 , wherein adjusting a focus of the first camera to the first focus distance further comprises at least one of: (i) adjusting a position of a lens along an optical axis of the first camera; (ii) adjusting a curvature of the lens; (iii) adjusting an index of refraction of the lens; (iv) adjusting distance between a first lens and a second lens of a lens system; and (v) moving a location of the lens system along the optical axis of the first camera. 
     
     
         6 . The method of  claim 5 , wherein adjusting the focus distance of the first camera further comprises:
 calibrating a plurality of focus distances of the lens system to a plurality of focus calibration voltage values; and   applying a focus calibration voltage value to the lens system to select the first focus distance.   
     
     
         7 . The method of  claim 6 , further comprising using interpolation and at least two calibrated focus distances to determine the focus calibration voltage value where the lens system produces an uncalibrated focus distance. 
     
     
         8 . The method of  claim 6  wherein the 3D scanner includes a second camera having an adjustable focus, the method further comprising:
 providing the first focus distance of the first camera to the processor; 
 adjusting, via the processor, the second camera to a second focus distance based on the first focus distance of the first camera; and 
 scanning the first object using the first focus distance of the first camera and a second focus distance of second camera. 
 
     
     
         9 . The method of  claim 5 , wherein adjusting the focus distance of the first camera further comprises calibrating a parameter of the lens system to the focus distance, the parameter being selected from the group consisting of: (i) principal point; (ii) lens distortion; (iii) focal length; (iv) first camera orientation; and (v) first camera position to a plurality of focus calibration voltages. 
     
     
         10 . The method of  claim 1 , wherein the first camera further includes an adjustable aperture, further comprising adjusting a size of the aperture. 
     
     
         11 . A three-dimensional scanning apparatus, comprising:
 a first camera configured to obtain an image of a first object, wherein the first camera is placed at a first distance from the first object, the first camera having an adjustable focus distance; and   a processor configured to adjust the adjustable focus distance of the first camera to a first focus distance that forms an image of the first object at an image plane of the first camera.   
     
     
         12 . The apparatus of  claim 11 , wherein the first camera is located at a second distance from a second object and the processor is configured to adjust a focus distance to a second focus distance that forms an image of the second object at the image plane of the first camera; and the first camera is configured to obtain an image of the second object at the second focus distance of the first camera. 
     
     
         13 . The apparatus of  claim 11 , wherein the processor adjusts the current focus distance to the first focus distance by performing at least one of: (i) obtaining a distance measurement from a distance measurement device that measures a time-of-flight of a light pulse; and (ii) determining the first focus distance as a focus distance at which a sharpness of an image of the first object reaches a substantial maximum. 
     
     
         14 . The apparatus of  claim 13 , wherein a difference between the current focus distance and the first focus distance is greater than a selected threshold, the processor further configured to divide a range of focus distances of the first camera into a preselected number of sub-ranges and adjust the focus distance by stepping through the preselected number of sub-ranges to determine a sub-range that includes the first focus distance. 
     
     
         15 . The apparatus of  claim 14 , wherein the processor is configured to adjust the focus distance of the first camera by performing at least one of: (i) adjusting a position of a lens along an optical axis of the first camera; (ii) adjusting a curvature of the lens; (iii) adjusting an index of refraction of the lens; (iv) adjusting distance between a first lens and a second lens of a lens system; and (v) moving a location of the lens system along the optical axis of the first camera. 
     
     
         16 . The apparatus of  claim 15 , wherein the processor is further configured to:
 calibrate a plurality of focus distances of the lens system to a plurality of focus calibration voltage values; and   apply a focus calibration voltage value that selects the first focus distance.   
     
     
         17 . The apparatus of  claim 16 , wherein the processor is further configured to produce an uncalibrated focus distance using interpolation and at least two calibrated focus distances to determine the focus calibration voltage value at the lens system for the uncalibrated focus distance. 
     
     
         18 . The apparatus of  claim 16  further comprising a second camera having an adjustable focus, wherein the processor is further configured to:
 adjust, via the processor, the second camera to a second focus distance based on the first focus distance applied at the first camera; and 
 scan the first object using the first focus distance of the first camera and the second focus distance of the second camera. 
 
     
     
         19 . The apparatus of  claim 15 , wherein the processor is further configured to adjust the focus distance of the first camera by calibrating a parameter of the lens system to the focus distance, the parameter being selected from the group consisting of: (i) principal point; (ii) lens distortion; (iii) focal length; (iv) first camera orientation; and (v) first camera position to a plurality of focus calibration voltages. 
     
     
         20 . The apparatus of  claim 11 , wherein the first camera further comprises an adjustable aperture. 
     
     
         21 . A method of scanning an object with a three-dimensional (3D) scanner, comprising:
 measuring a level of light intensity at a first camera of the 3D scanner; and   automatically adjusting an aperture of the first camera of the 3D scanner to a first aperture size based on the measured level of light intensity.   
     
     
         22 . The method of  claim 21 , further comprising calibrating a plurality of aperture sizes to a plurality of aperture voltage levels and selecting an aperture voltage level to adjust the aperture to the first aperture size. 
     
     
         23 . The method of  claim 21 , further comprising using interpolation and at least two calibrated aperture sizes to determine a voltage value that produces an uncalibrated aperture size. 
     
     
         24 . The method of  claim 22  further comprising calculating depth of fields for the plurality of aperture sizes and automatically selecting an aperture size based on both a measured light intensity and a depth of field. 
     
     
         25 . The method of  claim 21  further comprising:
 adjusting an aperture of a second camera of the 3D scanner to a second aperture size based on the first aperture size of the first camera; and 
 scanning the object using the first camera and the second camera. 
 
     
     
         26 . The method of  claim 25 , further comprising determining a first voltage applied to the first camera to obtain the first aperture size, determining an equivalent voltage from the first voltage that obtains the second aperture size at the second camera, and applying the equivalent voltage as a second voltage at the second camera. 
     
     
         27 . The method of  claim 21 , further comprising calibrating a parameter of a lens system selected from the group consisting of: (i) principal point; (ii) lens distortion; (iii) focal length; (iv) first camera orientation; and (v) first camera position to a plurality of aperture voltages. 
     
     
         28 . A three-dimensional (3D) scanning apparatus, comprising:
 a light intensity meter for measuring a level of light intensity at a first camera of the 3D scanning apparatus;   the first camera having an adjustable aperture; and   a processor configured to adjust the adjustable aperture of the first camera automatically based on the measured light level.   
     
     
         29 . The apparatus of  claim 28 , wherein the processor is further configured to calibrate a plurality of aperture sizes to a plurality of aperture voltage levels and select an aperture voltage level to adjust the aperture to the first aperture size. 
     
     
         30 . The apparatus of  claim 28 , wherein the processor is further configured to use interpolation and at least two calibrated aperture sizes to determine a voltage value that produces an uncalibrated aperture size. 
     
     
         31 . The apparatus of  claim 29 , wherein the processor is further configured to calculate depth of fields for the plurality of aperture sizes and automatically select an aperture size based on both a measured light intensity and a depth of field. 
     
     
         32 . The apparatus of  claim 28 , wherein the processor is further configured to:
 adjust an aperture of a second camera of the 3D scanner to a second aperture size based on the first aperture size of the first camera; and   scan the object using the first camera and the second camera.   
     
     
         33 . The apparatus of  claim 32 , wherein the processor is further configured to determine a first voltage applied to the first camera to obtain the first aperture size, determine an equivalent voltage from the first voltage that obtains the second aperture size at the second camera, and apply the equivalent voltage as a second voltage at the second camera. 
     
     
         34 . The apparatus of  claim 28 , wherein the processor is further configured to calibrate a parameter of a lens system selected from the group consisting of: (i) principal point; (ii) lens distortion; (iii) focal length; (iv) first camera orientation; and
 (v) first camera position to a plurality of aperture voltages.   
     
     
         35 . The apparatus of  claim 28 , wherein the light intensity meter comprises a photodetector array of the first camera.