Scanning system and calibration method for capturing precise three-dimensional information of objects
A scanning system includes a hand-held scanning device that generates two-dimensional images of a pattern reflected off an object. The system also includes a memory and processing unit. The memory stores a calibration table for the scanner and received scanned bitmap images. The processing unit generates three-dimensional information as to a scanned object. The scanning can be performed without knowledge or even precise control of the position of the object relative to the scanner. Random movement of the object during scanning is also possible. For example, the scanner is simply swept over the surface of the object by hand. Three-dimensional information of the object is obtained from the captured images using a calibration table for the scanner. A method of calibration of the scanner in X, Y and Z directions is also described. The scanner can be used for a variety of purposes, including medical and industrial purposes. The illustrated embodiment is in-vivo scanning of human teeth for purposes of orthodontic treatment planning and diagnosis.
1. A scanner for in-vivo scanning the oral cavity, the scanner comprising:
a light source,
a heated mirror directing light from said light source onto anatomical structures in or surrounding the oral cavity;
an electronic imaging device collecting light reflected off of said anatomical structures, said electronic imaging device comprising an array of pixels; and
a memory storing a three-axis (X, Y and Z) coordinate system calibration relationship for said scanner, said calibration relationship identifying: (1) pixel coordinates for said electronic imaging device, said pixel coordinates associated with distance information in a Z direction at at least two different Z distances, and (2) distance information in X and Y directions, at said at least two different Z distances;
wherein the heating of said mirror prevents fogging of said mirror during in-vivo scanning.
2. The scanner of claim 1 , wherein said scanner comprises a housing adapted to be held by the hand, and wherein said mirror is placed at the distal end of a probe extending from said housing.
3. The scanner of claim 1 , wherein said mirror is placed in a housing and wherein said mirror housing further comprises an AC conductive heating coil that heats said mirror.
4. The scanner of claim 1 , wherein said scanner further comprises a projection pattern and said light source projects said projection pattern onto said anatomical structures.
5. The scanner of claim 1 , wherein said mirror comprises a square mirror.
6. The scanner of claim 1 , wherein said mirror is heated to a temperature of approximately 40 degrees C. during in-vivo scanning.