Apparatus for extracting pattern features

• US 5,870,490 A
• Filed: 08/27/1996
• Issued: 02/09/1999
• Est. Priority Date: 04/16/1993
• Status: Expired due to Fees

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Takahashi, Tomoichi, Tateishi, Kazuyoshi, Watabe, Akinori
• Primary Examiner(s): CHANG, JON CARLTON
• Application Number:
  US08/697,603
• Time in Patent Office: 896 Days
• Field of Search: 382/154, 382/190, 382/203, 356/376, 356/387, 372/9, 372/14, 372/15, 359/196, 359/197, 359/202, 359/212, 359/213, 359/214, 359/215, 359/220, 359/221, 359/226, 359/298
• US Class Current: 382/154
• CPC Class Codes: G05B 19/37 for continuous-path control
• CPC Class Codes: G05B 2219/37359 Contour, to sense corners, edges of surface
• CPC Class Codes: G05B 2219/39033 Laser tracking of end effector, measure orientation of rotatable mirror
• CPC Class Codes: G05B 2219/40374 Control trajectory in case of distortion of visual input
• CPC Class Codes: G05B 2219/40576 Multisensory object recognition, surface reconstruction
• CPC Class Codes: G06V 20/64 Three-dimensional objects

Abstract

An apparatus is presented for extracting configurational features of an object formed by a number of surfaces with a two-dimensional laser pattern. Changes in the shape can be tracked, and speedy three-dimensional measurements are made possible in a small memory area without requiring parameter adjustment. The device comprises a two-dimensional laser pattern generating device which projects laser light in a desired two-dimensional pattern configuration, a three-dimensional position calculating device which synchronizes the timing of the laser light illumination with the timing of the detection of two-dimensional points. Three-dimensional coordinates of a surface point are rapidly calculated, then the surface parameters are determined by the three-dimensional positions of a number of points (three points or more). A pattern information generating device varies the pattern to be projected in accordance with the surface parameters so obtained, and a pattern recognition device controls the movements of a robot in accordance with variations in configuration based on the edge lines, vertexes and other features determined by a number of plane surfaces.

Claims

1. An apparatus for extracting configurational features of an object having a plurality of surfaces for a robot machine, comprising:

a two-dimensional laser pattern projection device comprising a semiconductor laser, a collimating lens, a lens support, supporting springs, a lens holder, a moving coil, and a magnetic circuit, for projecting laser light in a two-dimensional pattern, and in a projecting direction by deflecting a laser beam generated by said semiconductor laser by moving said collimating lens in a direction perpendicular to a light axis of the laser beam,

a three-dimensional position calculating device for calculating a three-dimensional position of a point illuminated by the laser light, and for determining a three-dimensional position of a measurement surface based on said three-dimensional position and information relating to a basic shape of said measurement surface, and

a configurational feature extracting means for extracting configurational features of said object having a plurality of surfaces, based on the three-dimensional position of the measurement surface;

wherein said collimating lens is supported by the lens holder, the lens support, and supporting springs, and the moving coil disposed in a direction perpendicular to the light axis for controlling the position of said collimating lens in a direction perpendicular to the light axis of said laser beam for controlling the deflection of said laser beam;

wherein said two-dimensional laser pattern projection device further includes a pattern information generating device, for altering the projection pattern of the laser light based on an illuminated position of said two-dimensional laser pattern on the object position of the measurement surface, said pattern information generating device determining surface parameters, and outputting command parameters to the two-dimensional laser pattern projection device on the direction of the laser.

2. An apparatus for extracting configurational features of an object having a plurality of surfaces for a robot machine, comprising:

a two-dimensional laser pattern projection device comprising a semiconductor laser, a collimating lens, a lens support, supporting springs, a lens holder, a moving coil, and a magnetic circuit, for projecting laser light in a two-dimensional pattern, and in a projecting direction by deflecting a laser beam generated by said semiconductor laser by moving said collimating lens in a direction perpendicular to a light axis of the laser beam;

a three-dimensional position calculating device for calculating a three-dimensional position of a point illuminated by the laser light, and for determining a three-dimensional position of a measurement surface based on said three-dimensional position and information relating to a basic shape of said measurement surface; and

a configurational feature extracting means for extracting configurational features of said object having a plurality of surfaces, based on the three-dimensional position of the measurement surface;

wherein said three-dimensional position calculating device determines the surface parameters relating to the three-dimensional position of the measurement surface from the three-dimensional positions of a plurality of points, and the number of constituting surfaces is determined from successive comparisons of the surface parameters obtained in each sequential calculation of the three-dimensional positions.

3. An apparatus for extracting configurational features of an object having a plurality of surfaces for a robot machine, comprising:

a two-dimensional laser pattern projection device comprising a semiconductor laser, a collimating lens, a lens support, supporting springs, a lens holder, a moving coil, and a magnetic circuit, for projecting laser light in a two-dimensional pattern, and in a projecting direction by deflecting a laser beam generated by said semiconductor laser by moving said collimating lens in a direction perpendicular to a light axis of the laser beam;

a three-dimensional position calculating device for calculating a three-dimensional position of a point illuminated by the laser light, and for determining a three-dimensional position of a measurement surface based on said three-dimensional position and information relating to a basic shape of said measurement surface; and

a configurational feature extracting means for extracting configurational features of said object having a plurality of surfaces, based on the three-dimensional position of the measurement surface;

wherein the configurational feature extracting means includes a pattern recognition device for classifying the position of the two-dimensional laser pattern on the object surfaces into a plurality of predetermined cases based on a number of feature points outputted from surface parameters which are determined by the three-dimensional position calculating device, and further includes a pattern information generating device for altering the projection direction and the two-dimensional pattern of the laser light in accordance with classified surfaces of the position of the laser pattern determined by said pattern recognition device.