Dimensioning system

• US 6,177,999 B1
• Filed: 08/25/1997
• Issued: 01/23/2001
• Est. Priority Date: 06/02/1995
• Status: Expired due to Term

• Current Assignee: Accu-Sort Systems Incorporated (Datalogic S.p.A.)
• Original Assignee: Accu-Sort Systems Incorporated (Datalogic S.p.A.)
• Inventors: Martin, David L., Romaine, John E., Wurz, Albert
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): Ratliff, Reginald A.
• Application Number:
  US08/918,196
• Time in Patent Office: 1,247 Days
• Field of Search: 356/386, 356/376, 356/380, 356/383
• US Class Current: 356/623
• CPC Class Codes: G01B 11/00 Measuring arrangements characterised by the use of optical techniques
• CPC Class Codes: G01B 11/0608 Height gauges

Abstract

The present invention provides a dimensioning system for determining the minimum size box necessary to enclose an object traveling on a moving conveyor. The dimensioning system is comprised of a light source which generates a scan beam that is moved by a mirrored wheel. A line scan camera whose field of view tracks the moving scan beam receives images of the scan beam and outputs a signal which is processed to compute a three dimensional box structure of the scanned object.

Claims

1. An apparatus for determining a dimension of an object traveling on a moving conveyor, the apparatus having means for moving a scanning beam across the conveyor such that the beam repeatedly intercepts the object at an angle e relative to a plane extending through the conveyor, the apparatus characterized by:

detecting means having a line field of view which maintains a constant orientation relative to the scanning beam as the beam moves across the conveyor and receives a reflected image of the beam at a plurality of image points; and

means for calculating the object dimension at each image point based upon the reflected images.

2. The apparatus of claim 1 wherein the detecting means is a line scan camera that outputs a signal which represents an object height relative to the conveyor at each image point.

3. The apparatus of claim 2 further characterized by a processor which receives the signal, calculates a value of the height at each image point thereby producing height data, stores data from a plurality of image points, and determines a three dimensional measurement of the object based on the height data.

4. The apparatus of claim 2 wherein:

said line scan camera has a lens and detector array;

said lens and detector array are mounted in a fixed angular relationship with respect to each other and an image plane defined at said selected location; and

said angular relationship is the Scheimpflug angle whereby an object passing through said selected location is in the scan camera'"'"'s focus over a depth of field of at least 304.8 mm (12 inches).

5. The apparatus of claim 4 wherein the depth of field is at least 914.4 mm (36 inches).

6. The apparatus of claim 1 wherein the detecting means is a position-sensitive detector that outputs a current which represents an object height relative to the conveyor at each image point.

7. The apparatus of claim 6 further characterized by a processor which receives the output current, calculates a value of the height at each image point thereby producing height data, stores data from a plurality of image points, and determines a three dimensional measurement of the object based on the height data.

8. The apparatus of claim 6 wherein:

said position-sensitive detector has a lens and detector array;

said lens and detector array are mounted in a fixed angular relationship with respect to each other and an image plane defined at said selected location; and

said angular relationship is the Scheimpflug angle whereby an object passing through said selected location is in the position-sensitive detector'"'"'s focus over a depth of field of at least 304.8 mm (12 inches).

9. The apparatus of claim 8 wherein the depth of field is at least 914.4 mm (36 inches).

10. An apparatus for determining a dimension of an object traveling on a moving conveyor, the apparatus having means for directing a scanning beam across the conveyor at a selected location such that the beam repeatedly intercepts the object at an angle θ

relative to a plane extending through the conveyor, the apparatus characterized by;

detecting means having a line field of view which maintains a constant orientation relative to the scanning beam as the beam moves across the conveyor and receives a reflected image of the beam at a plurality of image points;

means in the path of the moving beams for converting the light from an angular scan to substantially parallel moving beams; and

means for calculating the object dimension at each image point based upon the reflected images.

11. The apparatus of claim 10 further characterized by:

means for directing the line field of view parallel to said plane and aligned such that the detecting means receives a reflected image at a reference position when the reflected image originates at the conveyor;

said detecting means detecting the plurality of image points along the moving beam and outputting a signal corresponding to the image points; and

a processor which receives the signal, computes a distance d that each image point is offset from the reference position and an object height h at each image point, stores data from a plurality of image points, and determines a three dimensional measurement of the object based on the height data.

12. The apparatus of claim 11 wherein object height at each image point is calculated using the formula

13. The apparatus of claim 10 wherein said directing means and said converting means are a parabolic surface.

14. The apparatus of claim 10 wherein said directing means and said converting means are a Fresnel lens.

15. The apparatus of claim 10 wherein said directing means and said converting means are a holographic lens.

16. The apparatus of claim 10 wherein said directing means and said converting means are a multi-faceted parabolic surface.

17. The apparatus of claim 11 wherein said detecting means is a line scan camera that outputs a signal which represents the object height relative to the conveyor at each image point.

18. The apparatus of claim 17 wherein:

said line scan camera has a lens and detector array;

said lens and detector array are mounted in a fixed angular relationship with respect to each other and an image plane defined at said selected location; and

said angular relationship is the Scheimpflug angle whereby an object passing through said selected location is in the scan camera'"'"'s focus over a depth of field of at least 304.8 mm (12 inches).

19. The apparatus of claim 11 wherein the detecting means is a position-sensitive detector that outputs a current which represents the object height relative to the conveyor at each image point.

20. The apparatus of claim 19 wherein:

said position-sensitive detector has a lens and detector array;

said lens and detector array are mounted in a fixed angular relationship with respect to each other and an image plane defined at said selected location; and

said angular relationship is the Scheimpflug angle whereby an object passing through said selected location is in the position-sensitive detector'"'"'s focus over a depth of field of at least 304.8 mm (12 inches).

21. A method of determining a dimension of an object traveling on a moving conveyor comprising the steps of:

moving a scanning beam across the conveyor such that the beam repeatedly intercepts the object at an angle θ

relative to a plane extending through the conveyor;

providing detecting means having a line field of view which maintains a constant orientation relative to the scanning beam as the beam moves across the conveyor and receives a reflected image of the beam at a plurality of image points; and

calculating the object dimension at each image point based upon the reflected images.

22. The method of claim 21 further comprising the steps of:

directing the moving beam across the conveyor at a selected location; and

converting the beam from angular moving beams to substantially parallel moving beams.

23. The method of claim 22 further comprising the steps of:

directing the line field of view parallel to said plane and aligned such that the detecting means receives a reflected image at a reference position when the reflected image originates at the conveyor;

computing a distance d that each image point is offset from the reference position and an object height h at each image point; and

determining a three dimensional measurement of the object based on the height data.

24. The method of claim 23 wherein object height at each image point is calculated using the formula