Dimensional Detection System and Associated Method

• US 20110286007A1
• Filed: 05/21/2010
• Published: 11/24/2011
• Est. Priority Date: 05/21/2010
• Status: Active Grant

• Current Assignee: Nielco, Inc.
• Original Assignee: LTS Scale Company, LLC (Libra Invest Nederland BV)
• Inventors: Pangrazio, John Gregory, Pangrazio, John Alan, Pena-Gutierrez, Cesar, Brey, Kenneth Lloyd, Pangrazio, Robert Thomas
• Granted Patent: US 8,134,717 B2
• Time in Patent Office: Days
• US Class Current: 356/614
• CPC Class Codes: B66F 17/003 for fork-lift trucks
• CPC Class Codes: B66F 9/0755 Position control; Position detectors
• CPC Class Codes: G01B 11/00 Measuring arrangements characterised by the use of optical techniques

Abstract

An improved dimensional detection system is portable and can be used to characterize a workpiece. The dimensional detection system employs as few as a single focused light source and as few as a single camera along with a calibration data set to convert the illuminated pixels of an image of a beam on the workpiece into a cloud of real world points in space on an outer surface of the workpiece. The cloud of points can be processed to characterize the workpiece, such as by determining the right hexahedron that would encompass all of the real world points in space and which could be used to determine a dimensional weight of the workpiece.

Claims

1. A method characterizing a workpiece with the use of a measurement apparatus that comprises a focused light source that is structured to project a beam onto the workpiece, an image collection device that is structured to detect a reflection of the beam on the workpiece and to generate a number of images, and an image analysis device that has access to a calibration data set, the image collection device and the image analysis device being in electronic communication, the method comprising:

projecting at least a first beam onto the workpiece;

capturing an image that comprises a number of illuminated pixels representative of at least a portion of the at least first beam on the workpiece;

employing the calibration data set to convert at least some of the illuminated pixels of the image into a number of points in space that are each representative of a point on a surface of the workpiece; and

processing the points in space in a predetermined fashion to generate the characterization of the workpiece.

2. The method of claim 1, further comprising generating as the characterization of the workpiece a hexahedron that would contain the workpiece.

3. The method of claim 1, further comprising:

retrieving from the calibration data set a number of coefficients that correspond with the at least first beam;

employing at least some of the number of coefficients along with a number of equations to convert a set of U, V coordinates for an illuminated pixel of the image that is representative of a point on the surface of the workpiece that is illuminated by the at least first beam into a set of X, Y, Z coordinates for a point in space that corresponds with the point on the surface.

4. The method of claim 3, further comprising projecting the at least first beam onto the workpiece at a predetermined angle oblique to vertical, the number of coefficients being associated with the predetermined angle.

5. The method of claim 4, further comprising:

projecting another beam onto the workpiece at another predetermined angle oblique to vertical;

capturing another image that comprises a number of illuminated pixels representative of at least a portion of the another beam on the workpiece;

retrieving from the calibration data set another number of coefficients that are associated with the another predetermined angle;

employing at least some of the another number of coefficients along with the number of equations to convert a set of U, V coordinates for an illuminated pixel of the another image that is representative of a point on the surface of the workpiece that is illuminated by the another beam into a set of X, Y, Z coordinates for a point in space that corresponds with the point on the surface.

6. The method of claim 3, further comprising:

performing the employing to convert each of a plurality of sets of U,V coordinates for a plurality of illuminated pixels of the image into a plurality of sets of X,Y,Z coordinates for a plurality of points in space;

subjecting two of the three coordinates X, Y, and Z of each of at least some of the points in space to an algorithm to generate a polygon that would enclose the two of the three coordinates X, Y, and Z of the at least some of the points in space;

applying to the polygon a value of a third one of the three coordinates X, Y, and Z of at least one point in space of the at least some of the points in space to generate a polyhedron as the characterization of the workpiece.

7. The method of claim 6, further comprising:

generating as the polygon a rectangle;

applying as the value of the third one of the three coordinates X, Y, and Z a maximum value of the third one of the three coordinates X, Y, and Z from among the at least some of the points in space;

generating as the polyhedron a right hexahedron as the characterization of the workpiece.

8. The method of claim 6, further comprising:

determining a volume of the polyhedron;

applying to the volume a predetermined factor to calculate a dimensional weight of the workpiece; and

assigning as the effective weight of the workpiece the greater of the dimensional weight of the workpiece and an actual weight of the workpiece.

9. The method of claim 1, further comprising:

projecting as the at least a first beam a plurality of beams each being sequentially projected and oriented at a predetermined angle from among a plurality of predetermined angles oblique to vertical;

capturing for each beam of at least some of the plurality of beams an image that comprises a number of illuminated pixels representative of at least a portion of the beam on the workpiece;

for each image, employing a number of coefficients from the calibration data set that are associated with the predetermined angle of the beam to convert at least some of the illuminated pixels of the image into a number of points in space that are each representative of a point on the surface of the workpiece; and

processing the points in space in a predetermined fashion to generate the characterization of the workpiece.

10. A method of generating a calibration data set for a measurement apparatus that comprises a focused light source that is structured to project a beam onto a workpiece, an image collection device that is structured to detect a reflection of the beam on the workpiece and to generate a number of images, and an image analysis device that has access to the calibration data set, the image collection device and the image analysis device being in electronic communication, the method comprising:

projecting a beam oriented at a predetermined angle oblique to a reference axis onto a calibration platform that comprises a plurality of indices and that is disposed at each of a plurality of positions along the reference axis;

capturing at each position of at least some of the plurality of positions an image that comprises a number of illuminated pixels representative of at least a portion of the beam on at least some of the indices of the calibration platform at the position;

for each image, employing the position of the calibration platform along the reference axis and a representation of the calibration platform to generate for each of at least some of the illuminated pixels a point in space that is representative of a point on a surface of the calibration platform at the position along the reference axis that is illuminated by the beam; and

generating a calibration data set from at least some of the points in space.

11. The method of claim 10, further comprising generating as the calibration data set a data set that comprises a number of coefficients that correspond with the predetermined angle and that are usable in a number of equations to enable an illuminated pixel of an image of a workpiece that is illuminated by an analysis beam at the predetermined angle to be transformed into a point in space that corresponds with a point on a surface of the workpiece that is illuminated by the analysis beam.

12. The method of claim 11, further comprising:

projecting onto the calibration platform another beam oriented at another predetermined angle oblique to the reference axis;

capturing at each of a plurality of positions of the calibration platform along the reference axis another image that comprises a number of illuminated pixels representative of at least a portion of the another beam on the calibration platform; and

for each such another image, employing the position of the calibration platform along the reference axis and the representation of the calibration platform to generate for each of at least some of the illuminated pixels another point in space that is representative of a point on the surface of the calibration platform at the position along the reference axis that is illuminated by the beam; and

employing the another points in space to generate as a part of the calibration data set another data set that comprises another number of coefficients that correspond with the another predetermined angle and that are usable in the number of equations to enable an illuminated pixel of an image of the workpiece that is illuminated by another analysis beam at the another predetermined angle to be transformed into a point in space that corresponds with a point on the surface of the workpiece that is illuminated by the another analysis beam.

13. An apparatus structured to characterize a workpiece, the apparatus comprising

a measurement apparatus that comprises a focused light source, an image collection device, and a control system;

the control system being operable to cause the focused light source to project a beam onto the workpiece;

the control system being operable to cause the image collection device to detect a reflection of the beam on the workpiece and to generate a number of images;

the control system being operable to cause the number of images to be communicated to an image analysis device that having access to a calibration data set;

the control system having available thereto one or more routines which, when executed by the control system, cause the measurement apparatus to perform operations comprising;

projecting at least a first beam onto the workpiece;

capturing an image that comprises a number of illuminated pixels representative of at least a portion of the at least first beam on the workpiece;

employing the calibration data set to convert at least some of the illuminated pixels of the image into a number of points in space that are each representative of a point on a surface of the workpiece; and

processing the points in space in a predetermined fashion to generate the characterization of the workpiece.

14. The apparatus of claim 13 wherein the operations further comprise generating as the characterization of the workpiece a hexahedron that would contain the workpiece.

15. The apparatus of claim 13 wherein the operations further comprise:

retrieving from the calibration data set a number of coefficients that correspond with the at least first beam;

employing at least some of the number of coefficients along with a number of equations to convert a set of U, V coordinates for an illuminated pixel of the image that is representative of a point on the surface of the workpiece that is illuminated by the at least first beam into a set of X, Y, Z coordinates for a point in space that corresponds with the point on the surface.

16. The apparatus of claim 15 wherein the operations further comprise projecting the at least first beam onto the workpiece at a predetermined angle oblique to vertical, the number of coefficients being associated with the predetermined angle.

17. The apparatus of claim 16 wherein the operations further comprise:

projecting another beam onto the workpiece at another predetermined angle oblique to vertical;

capturing another image that comprises a number of illuminated pixels representative of at least a portion of the another beam on the workpiece;

retrieving from the calibration data set another number of coefficients that are associated with the another predetermined angle;

employing at least some of the another number of coefficients along with the number of equations to convert a set of U, V coordinates for an illuminated pixel of the another image that is representative of a point on the surface of the workpiece that is illuminated by the another beam into a set of X, Y, Z coordinates for a point in space that corresponds with the point on the surface.

18. The apparatus of claim 15 wherein the operations further comprise:

performing the employing to convert each of a plurality of sets of U,V coordinates for a plurality of illuminated pixels of the image into a plurality of sets of X, Y, Z coordinates for a plurality of points in space;

subjecting two of the three coordinates X, Y, and Z of each of at least some of the points in space to an algorithm to generate a polygon that would enclose the two of the three coordinates X, Y, and Z of the at least some of the points in space;

applying to the polygon a value of a third one of the three coordinates X, Y, and Z of at least one point in space of the at least some of the points in space to generate a polyhedron as the characterization of the workpiece.

19. The apparatus of claim 18 wherein the operations further comprise:

generating as the polygon a rectangle;

applying as the value of the third one of the three coordinates X, Y, and Z a maximum value of the third one of the three coordinates X, Y, and Z from among the at least some of the points in space;

generating as the polyhedron a right hexahedron as the characterization of the workpiece.

20. The apparatus of claim 18 wherein the operations further comprise:

determining a volume of the polyhedron;

applying to the volume a predetermined factor to calculate a dimensional weight of the workpiece; and

assigning as the effective weight of the workpiece the greater of the dimensional weight of the workpiece and an actual weight of the workpiece.

21. The apparatus of claim 13 wherein the operations further comprise:

projecting as the at least a first beam a plurality of beams each being sequentially projected and oriented at a predetermined angle from among a plurality of predetermined angles oblique to vertical;

capturing for each beam of at least some of the plurality of beams an image that comprises a number of illuminated pixels representative of at least a portion of the beam on the workpiece;

for each image, employing a number of coefficients from the calibration data set that are associated with the predetermined angle of the beam to convert at least some of the illuminated pixels of the image into a number of points in space that are each representative of a point on the surface of the workpiece; and

processing the points in space in a predetermined fashion to generate the characterization of the workpiece.

22. The apparatus of claim 13 wherein the measurement apparatus is disposed on a forklift truck having a first mast and a second mast, the focused light source being disposed on one of the first mast and the second mast, the image collection device being a camera disposed on the other of the first mast and the second mast.

23. The apparatus of claim 22 wherein the measurement apparatus further comprises the image analysis device, the camera and the image analysis device being in electronic communication.