Rapid three-dimensional surface digitizer

• US 4,705,401 A
• Filed: 08/12/1985
• Issued: 11/10/1987
• Est. Priority Date: 08/12/1985
• Status: Expired due to Term

• Current Assignee: Cyberware Laboratory Incorporated
• Original Assignee: Cyberware Laboratory Incorporated
• Inventors: Addleman, Lloyd A., Addleman, David A.
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US06/764,302
• Time in Patent Office: 820 Days
• Field of Search: 356/1, 356/375, 356/376, 358/107
• US Class Current: 356/606
• CPC Class Codes: G01B 11/2518 Projection by scanning of the object
• CPC Class Codes: G05B 19/4207 in which a model is traced or scanned and corresponding data recorded

Abstract

The invention is a method and apparatus for automatic mensuration of three-dimensional surfaces. The surface is sensed via non-contact optical triangulation means and the optically produced image measured by electronic means. The electronic measurements are encoded as binary data and passed to a digital computer for storage, analysis and other functions. The invention is significant because of the speed and relative simplicity of the method and a provision for alleviating shadowing from large surface irregularities. The apparatus has no moving parts, excepting a mechanism to provide for movement of the apparatus relative to the surface so as to progressively view the entire surface. This invention projects two or more planes of light which intersect the surface at known angles, producing illuminated lines. Said lines are viewed by a video type camera placed at a known angle away from the planes so that displacements in the line may be sensed. Electronic circuits detect and measure points on the line and transfer the data to a digital computer.

Claims

1. An apparatus for performing high speed noncontacting mensuration of 3-dimensional surfaces comprising:

a means for illuminating said surface with one or more planes of light intersecting said surface and producing contour lines;

a means for moving said surface relative to said planes of light;

a means for sensing points on said contour lines reflected from said surface;

a means for accurately determining the position of said points over a wide dynamic range of reflected light intensity and beam spreading, whereby a wide variety of surfaces can be measured without adjusting sensor sensitivity or lens aperture;

said means including a circuit wherein the sensor output is divided into two parts, the first being delayed before connection to one input of an amplitude comparator, the second connected to the remaining input of the comparator resulting in an amplitude and distortion insensitive timing detector;

a means for storing the point position data;

a means to provide synchronization for all parts of the apparatus.

2. An apparatus as defined in claim 1 wherein said surface movement is a rotation about an axis.

3. An apparatus as defined in claim 1 wherein said sensing means comprises a video camera with its field of view divided so as to observe multiple contour lines simultaneously.

4. An apparatus as defined in claim 1 wherein the means for storing the point position data functions in the order sensed.

5. An apparatus as defined in claim 1 wherein the scanning means includes a sensor with an anamorphic lens to increase the resolution of the surface coordinate lying in the plane of light and toward said sensor.