Method and apparatus for determining the configuration of a workpiece

• US 5,999,642 A
• Filed: 06/11/1997
• Issued: 12/07/1999
• Est. Priority Date: 04/22/1996
• Status: Expired due to Fees

• Current Assignee: Malcolm T. Gilliland
• Original Assignee: Malcolm T. Gilliland
• Inventors: Gilliland, Malcolm T.
• Primary Examiner(s): Kelley, Christopher S.
• Application Number:
  US08/872,821
• Time in Patent Office: 909 Days
• Field of Search: 382/154, 382/318, 382/152, 382/319, 348/42, 348/47, 348/86, 348/90, 356/3, 356/12, 356/376, 356/237
• US Class Current: 382/154
• CPC Class Codes: B23K 9/1274 Using non-contact, optical means, e.g. laser means
• CPC Class Codes: G05B 19/401 characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/37208 Vision, visual inspection of workpiece
• CPC Class Codes: G05B 2219/37555 Camera detects orientation, position workpiece, points of workpiece
• CPC Class Codes: G05B 2219/40293 Gantry, portal
• CPC Class Codes: G06T 7/55 from multiple images

Abstract

The present invention provides a method and an apparatus for scanning an object to obtain data on the object and determine the configuration of the object. A gantry (12) allows movement along a first direction (A-A'"'"'). A set of platforms (14A, 14B) allows movement along a second direction (B-B'"'"'). A set of cameras (16A and 16B) provide additional degrees of freedom and also provide for scanning the object (10) to obtain information about the object. The freedom of movement provided by the gantry, the platforms, and the cameras allows the object to be completely scanned. In addition, once the initial scanning process has been completely, areas which require additional scanning, such as compartments (10D), are identified. The cameras are then positioned, such as directly above or inside a compartment, and then the compartment is scanned to obtain information about the compartment that could not be obtained from the initial scanning procedure. The data obtained from the initial scan and any subsequent scans is processed to determine the configuration of the object. The information concerning the configuration is then used to perform a welding, cutting or other operation on the object.

Claims

1. A method for determining the configuration of an object, comprising the steps of:

setting a first camera to a first camera initial position;

setting a second camera to a second camera initial position;

scanning said object from said first camera initial position to a first camera end position to obtain data on a plurality of first camera observed points for said object, said data for a said first camera observed point including at least one of a picture of said object and ranging information to said object;

scanning said object from said second camera initial position to a second camera end position to obtain data on a plurality of second camera observed points for said object, said data for a said second camera observed point including at least one of a picture of said object and ranging information to said object;

processing said data for said first camera observed points and said second camera observed points to determine valid observed points;

inspecting said valid observed points to define a first plane, said first plane comprising a first plurality of said valid observed points;

inspecting said valid observed points to define a second plane, said second plane comprising a second plurality of said valid observed points;

determining an intersection line for said first plane and said second plane;

determining whether said intersection line is a straight line or is a curved line;

if said intersection line is a straight line then specifying said intersection line by at least a starting point and an ending point; and

if said intersection line is a curved line then specifying a plurality of points for said intersection line.

2. A method for determining the configuration of an object, comprising the steps of:

setting a first camera to a first camera initial position;

setting a second camera to a second camera initial position;

scanning said object from said first camera initial position to a first camera end position to obtain data on a plurality of first camera observed points for said object, said data for a said first camera observed point including at least one of a picture of said object and ranging information to said object;

scanning said object from said second camera initial position to a second camera end position to obtain data on a plurality of second camera observed points for said object, said data for a said second camera observed point including at least one of a picture of said object and ranging information to said object;

processing said data for said first camera observed points and said second camera observed points to determine valid observed points;

inspecting said valid observed points to define a first plane, said first plane comprising a first plurality of said valid observed points;

inspecting said valid observed points to define a second plane, said second plane comprising a second plurality of said valid observed points;

determining an intersection line for said first plane and said second plane;

determining whether said intersection line is a straight line or is a curved line;

if said intersection line is a straight line then specifying said intersection line by at least a starting point and an ending point; and

if said intersection line is a curved line then performing the steps of;

selecting a first point and a second point for said intersection line, said first point and said second point being points on said intersection line and being separated by a first distance;

defining a direct line by said first point and said second point;

defining a desired curved line by said first point, said second point, and points on said intersection line between said first point and said second point;

determining a maximum difference between said direct line and said desired curved line;

if said maximum difference is greater than a predetermined amount then selecting a different second point, said different second point being separated from said first point by less than said first distance; and

repeating said steps of defining said direct line, defining said desired curved line, and determining said maximum difference until said maximum difference is not greater than said predetermined amount; and

when said first point and said second point have been selected wherein said maximum difference is not greater than said predetermined amount, storing said first point and said second point and then, using said second point as a next said first point, repeating the above steps until said plurality of points for said intersection line have been selected.

3. An apparatus for determining the configuration of an object, comprising:

a first camera for scanning said object to obtain data on a plurality of first camera observed points for said object, said data for a said first camera observed point including at least one of a picture of said object and ranging information to said object;

a second camera for scanning said object to obtain data on a plurality of second camera observed points for said object, said data for a said second camera observed point including at least one of a picture of said object and ranging information to said object;

first means for moving said first camera along a first path from a first camera initial position to a first camera end position;

second means for moving said second camera along a second path from a second camera initial position to a second camera end position; and

a controller for controlling the operation of said first camera, said second camera, said first means, and said second means, for receiving said data, for processing said data for said first camera observed points and said second camera observed points to determine valid observed points, and processing said valid observed points to define a first plane and a second plane, for determining an intersection line for said first plane and said second plane, for determining whether said intersection line is a straight line or is a curved line, for specifying said intersection line by at least a starting point and an ending point if said intersection line is a straight line, and for specifying a plurality of points for said intersection line if said intersection line is a curved line.

4. An apparatus for determining the configuration of an object, comprising:

a first camera for scanning said object to obtain data on a plurality of first camera observed points for said object, said data for a said first camera observed point including at least one of a picture of said object and ranging information to said object;

a second camera for scanning said object to obtain data on a plurality of second camera observed points for said object, said data for a said second camera observed point including at least one of a picture of said object and ranging information to said object;

first means for moving said first camera along a first path from a first camera initial position to a first camera end position;

second means for moving said second camera along a second path from a second camera initial position to a second camera end position; and

a controller for controlling the operation of said first camera, said second camera, said first means, and said second means, for receiving said data, for processing said data for said first camera observed points and said second camera observed points to define a first plane and a second plane, for determining an intersection line for said first plane and said second plane, for determining whether said intersection line is a straight line or is a curved line, for specifying said intersection line by at least a starting point and an ending point if said intersection line is a straight line, and, if said intersection line is a curved line then for selecting a first point and a second point for said intersection line, said first point and said second point being points on said intersection line and being separated by a first distance, for defining a direct line by said first point and said second point, for defining a desired curved line by said first point, said second point, and points on said intersection line between said first point and said second point, for determining a maximum difference between said direct line and said desired curved line, for selecting a different second point if said maximum difference is greater than a predetermined amount, said different second point being separated from said first point by less than said first distance, until said maximum difference is not greater than said predetermined amount, and then for storing said first point and said second point, for using said second point as a next said first point, and for defining additional direct lines until said plurality of points for said intersection line have been selected.