Detection of three-dimensional information using a projected point or line of light

• US 4,494,874 A
• Filed: 07/07/1981
• Issued: 01/22/1985
• Est. Priority Date: 07/07/1981
• Status: Expired due to Fees

• Current Assignee: Solid Photography Incorporated
• Original Assignee: Robotic Vision Systems, Inc. (Omron Corporation)
• Inventors: Ross, Joseph, DiMatteo, Paul
• Primary Examiner(s): Rosenberger, R. A.
• Application Number:
  US06/281,068
• Time in Patent Office: 1,295 Days
• Field of Search: 356/376, 356/1, 356/4, 250/205
• US Class Current: 356/608
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures

Abstract

An object is scanned first with a flying light spot from a variable-intensity light-spot projector, and the reflected light is used as signals to point by point modify the output of the projector in accordance with the intensity of the respective reflective-light signal. Thereupon the object is scanned a second time and the projector instructed to apply less light than before to those points of the object from which a strong reflected-light signal was received during the first scan, and to apply more light to points from which a weak reflected-light signal was received during the first scan.

Claims

1. A method of detecting three-dimensional information, comprising the steps of:

projecting a variable-intensity flying spot of light onto an object to be scanned;

effecting a first scan by causing relative movement between object and light spot;

receiving light-intensity signals in a single reflected light ray from the object point-by-scanned-point and modifying the intensity of the light spot in accordance with each received signal;

effecting a second scan by causing relative movement between object and light spot; and

reducing the light-spot intensity during the second scan at such points of the object where the signal was strong during the first scan, and increasing the light-spot intensity during the second scan at such points where the signal was weak during the first scan, said steps of effecting a first scan and a second scan comprising measurements of a multiplicity of points independent of light intensity at the object, so that accuracy of said measurements is not influenced by the light intensity at the object, the light-spot intensity during said second scan being dependent on said light-intensity signals of said first scan for preventing inaccuracy due to measurement delay and lag in modifying by a distance equal to scan velocity multiplied by measurement delay time.

2. In an arrangement for detecting three-dimensional information, a combination comprising:

means for projecting a variable-intensity flying spot of light onto a object to be scanned; and

means for receiving during a first scanning of the object, light-intensity signals in a single reflected light ray back from the object, point-by-scanned-point and for modifying the intensity of the projected light spot in accordance with each such signal received, for reducing, during the subsequent second scan, the light-spot intensity at such points of the object where the signal was strong during the first scan, and for increasing the light-spot intensity during the second scan at such points of the object where the signal was weak during the first scan, said first scan and second scan comprising measurements of a multiplicity of points independent of light intensity at the object so that accuracy of said measurements is not influenced by the light intensity at the object, the light-spot intensity during said second scan being dependent on said light-intensity signals of said first scan for preventing inaccuracy due to measurement delay and lag in modifying by a distance equal to scan velocity multiplied by measurement delay time.

3. A combination as defined in claim 2, wherein said projection means comprises a variable light-intensity flying light spot projector.

4. A combination as defined in claim 2, wherein said receiving means comprises a camera.

5. A combination as defined in claim 2, wherein said reducing means comprises a control logic.

6. A combination as defined in claim 3, wherein said receiving means comprises a camera;

and said reducing means comprises a control logic connected between said camera and said projector.