Sensor-illumination system for use in three-dimensional measurement of objects and assemblies of objects

• US 4,645,348 A
• Filed: 09/01/1983
• Issued: 02/24/1987
• Est. Priority Date: 09/01/1983
• Status: Expired due to Term

• Current Assignee: Perceptron Incorporated (Atlas Copco AB)
• Original Assignee: Perceptron Incorporated (Atlas Copco AB)
• Inventors: Barlow, Neil E., Salinger, Jeremy, Dewar, Robert, Waldecker, Thomas J.
• Primary Examiner(s): ROSENBERGER, RICHARD A
• Application Number:
  US06/528,726
• Time in Patent Office: 1,272 Days
• Field of Search: 356/375, 356/376, 356/394, 356/1, 382/57
• US Class Current: 356/603
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns

Abstract

A three-dimensional triangulation-type sensor-illumination system adapted for connection to a machine vision computer. The illumination source in the preferred system comprises a unique cross hair light pattern which provides sufficient image data to the computer to enable the computer to make three-dimensional measurements of a wide variety of features, including edges, corners, holes, studs, designated portions of a surface and intersections of surfaces. The illumination source and sensor are both mounted within a single housing in a specific position and orientation relative to one another, thereby permitting the system to be internally calibrated. In addition, the sensor-illuminator unit is preferably mounted in a test fixture so that the light source is substantially normal to the surface of the part to be examined and the sensor is thereby positioned at a perspective angle relative thereto.

Claims

1. A triangulation-type sensor-illuminator assembly for generating image data usable by a machine vision computer to determine three-dimensional measurements of an object comprising:

a housing adapted for mounting to a test fixture supporting the object to be examined;

light source means fixedly mounted at a precise location and orientation within said housing for projecting onto said object a predetermined structured light pattern;

optical array sensor means for receiving the reflected light image off said object and producing electrical signals whose values are approximately proportional to the intensity of the light impinging upon said sensor means at each resolvable point in its array, said optical sensor means being fixedly mounted within said housing at a precise location and orientation relative to said light source means so that said sensor means obtains a perspective view of the image of said structured light pattern on said object; and

control circuit means located within said housing and connected to said light source means and said optical sensor means and having stored therein for subsequent transfer to a machine vision computer to which said assembly may be connected, calibration data for said assembly comprising a list identifying with respect to each resolvable point in said sensor array the location in three-dimensional space relative to a reference point associated with said housing, the point at which said object must be located for such resolvable point to be illuminated by the reflected image of said structured light pattern.

2. The sensor-illuminator assembly of claim 1 wherein said control circuit means further has stored therein a code uniquely identifying said system which is adapted to be transmitted by said control circuit means to a machine vision computer to which said system may be connected.

3. The sensor-illuminator assembly of claim 1 wherein said housing is mounted to the test fixture supporting said object so that said predetermined structured light pattern is projected onto said object at an angle substantially normal to the surface of said object.