Methods and apparatuses of detecting foreign particles or faults in a plurality of filled containers

• US 7,560,720 B2
• Filed: 08/29/2005
• Issued: 07/14/2009
• Est. Priority Date: 08/27/2004
• Status: Active Grant

• Current Assignee: Møller & Devicon A/S (Robert Bosch GmbH)
• Original Assignee: Møller & Devicon A/S (Robert Bosch GmbH)
• Inventors: Voigt, Aksel, Sorensen, Per T., Nielsen, Henrik M.
• Primary Examiner(s): Lee; John R
• Application Number:
  US11/574,360
• Publication Number:
  US 20080001104A1
• Time in Patent Office: 1,415 Days
• Field of Search: 250/559.46, 250/223.B, 356/240.1, 356/427, 356/428, 209/524, 209/526, 348/91, 348/127, 382/142
• US Class Current: 250/559.46
• CPC Class Codes: G01N 21/8851 Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002
• CPC Class Codes: G01N 21/9027 in containers after filling

Abstract

A method of detecting unwanted objects or faults in containers containing a fluid or liquid includes: (a) moving the containers along a path of travel; (b) providing; a light source emitting light of a specific spectral distribution, wherein the containers and their contents are at least partly transparent or translucent at the specific spectral distribution; (c) providing a camera for detecting light at the specific spectral distribution, wherein (1) the path of travel intersects a field of view defined by the camera, and (2) the camera registers a sequence of digital images as the containers pass between the light source and the camera; (d) selecting a part of each of the digital images that corresponds to the outline of a specific container; and (e) processing a sequence of the parts of the digital images so as to detect the unwanted objects or faults in the specific container.

Claims

1. A method of detecting unwanted objects or faults in a plurality of containers including a fluid or liquid, said method comprising the steps of:

providing a path of travel along which said plurality of containers are conveyed;

moving said plurality of containers along said path of travel;

providing a light source emitting light of a specific spectral distribution, said light source being positioned at one side of said path of travel, wherein said containers are at least partly transparent or translucent to the light at said specific spectral distribution, said fluid or liquid being at least partly transparent or translucent to light at said specific spectral distribution;

providing a first camera including a CMOS chip for detecting light at said specific spectral distribution emitted from said light source, wherein said first camera defines a field of view, said path of travel intersects said field of view, and said CMOS chip produces a digital image comprising a specific number of pixels;

rotating each of said containers so as to bring said fluid contained in each of said containers in motion;

stopping said rotation of each of said containers said fluid still rotating therein;

said first camera registering a sequence of digital images as said container passes between said light source and said camera;

selecting a part of each of said digital images, said part substantially corresponding to the outline of a specific container;

transmitting each of said parts to a digital image processing unit; and

processing a sequence of said parts of digital images so as to detect either the presence or absence of said unwanted objects or faults in said specific container.

2. The method according to claim 1, wherein said processing is constituted by said digital image processing unit comparing at least two of said parts of two specific digital images to detect unwanted objects or faults in said specific container.

3. The method according to claim 1, wherein said processing is constituted by said digital image processing unit analyzing at least one digital image to detect unwanted objects or faults in said specific container.

4. The method according to claim 1, wherein said processing is constituted by a subtraction of two images in sequence or out of sequence.

5. The method according to claim 1, wherein said processing is constituted by a comparison of said part of a specific digital image to a reference image for detecting unwanted objects or faults in said specific container.

6. The method according to claim 1, wherein said containers are conveyed at a substantially constant speed along said path of travel.

7. The method according to claim 1, further comprising:

providing a second camera including a second CMOS chip for detecting light at said specific spectral distribution emitted from a second light source, a second line of sight being defined between said second light source and said second camera, wherein said path of travel intersects with said second line of sight; and

said second CMOS chip produces a digital image comprising a second specific number of pixels;

wherein said second camera registers a second sequence of frames constituting a second multitude of digital images as said container passes between said second light source and said second camera;

selecting a second part of each of said digital images of said second sequence, said second part substantially corresponding to the outline of said specific container;

transmitting each of said second parts to said digital image processing unit;

said digital image processing unit processing said second multitude of said parts of digital images so as to detect said unwanted objects or faults in said specific container; and

comparing the result of said second processing to said first processing in order to confirm the result of said first processing.

8. A method of detecting unwanted objects or faults in a plurality of containers including a fluid or liquid, said method comprising the steps of:

providing a path of travel along which said plurality of containers are conveyed;

moving said plurality of containers along said path of travel;

providing a first light source emitting light of a specific spectral distribution, said light source being positioned at one side of said path of travel, wherein said containers are at least partly transparent or translucent to light at said specific spectral distribution, and said fluid or liquid is at least partly transparent or translucent to light at said specific spectral distribution;

providing a second light source emitting light of said specific spectral distribution, said second light source being positioned at one side of said path of travel;

providing a first light detection device for detecting light at said specific spectral distribution emitted from said first light source, wherein said first light detection device defines a first field of view, said path of travel intersects said first field of view and said first light detection device produces a first digital image comprising a specific number of pixels;

providing a second light detection device for detecting light at said specific spectral distribution emitted from said second light source, wherein said second light detection device defines a second field of view, said path of travel intersects said second field of view, and said second light detection device produces a second digital image comprising a second specific number of pixels;

said first and said second light detection device registering a first and second sequence of digital images as said container passes said first and said second field of view respectively;

selecting a part of each of said digital images of said first and said second sequence, said part substantially corresponding to the outline of a specific container;

transmitting each of said parts to a digital image processing unit;

said digital image processing unit processing each of said parts of said digital images so as to detect said unwanted objects or faults in said specific container; and

said processing resulting in either an establishment of an object or fault present or not present in said specific container.

9. The method according to claim 8, wherein said first and said second light detection units are constituted by cameras each including at least one CMOS chip for producing said first and said second digital images.

10. An apparatus for detecting unwanted objects or faults in a plurality of containers including a fluid or liquid, said apparatus comprising:

a frame;

a conveyor mounted in said frame constituting a path of travel for said plurality of containers, said conveyor defining an input and a corresponding output, said input receiving said plurality of containers, said output outputting said plurality of containers;

a first light source emitting light of a specific spectral distribution mounted in said frame, wherein said first light source is positioned at one side of said path of travel, said containers are at least partly transparent or translucent to light at said specific spectral distribution, and said fluid or liquid is at least partly transparent or translucent to light at said specific spectral distribution;

a first camera including a first CMOS chip for detecting light at said specific spectral distribution emitted from said first light source, said first camera defining a first field of view, wherein said first camera is mounted to said frame, and said path of travel intersects said first field of view, said first CMOS chip produces a first digital image comprising a first specific number of pixels, said first camera registers first sequence of digital images as a specific container passes said first field of view; and

a first digital image processing unit electrically connected to said first camera;

wherein said first camera selects a part of each of said digital images substantially corresponding to the outline of a specific container and transmits said part to said digital image processing unit;

wherein said first digital image processing unit processes a sequence of said parts of said digital images so as to detect the presence or absence of said unwanted objects or faults in said specific container.

11. The apparatus according to claim 10 wherein said conveyor is selected from the group consisting of at least one of a rotating carrousel, a belt conveyor, and a chain conveyor.

12. The apparatus according to claim 11 wherein said conveyor is directly driven by a drive mechanism selected from the group consisting of a servo motor, a step motor, a linear motor, and a gear means.

13. The apparatus according to claim 10, wherein each of said containers is rotated in either clock-wise or counter-clockwise direction by rotating means so as to bring said fluid contained in each of said containers in motion.

14. The apparatus according to claim 10, further comprising:

a second light source emitting light of said specific spectral distribution mounted in said frame, said second light source being positioned at one side of said path of travel; and

a second camera including a second CMOS chip for detecting light at said specific spectral distribution emitted from said second light source, wherein said second camera defines a second field of view, said path of travel intersects said second field of view, said second CMOS chip produces a second digital image comprising a second specific number of pixels, and said second camera registers a second sequence of digital images as said specific container passes said second field of view.

15. The apparatus according to claim 10, further comprising:

a second camera including a second CMOS chip for detecting light at said specific spectral distribution emitted from said first light source, wherein said second camera defines a second field of view, said path of travel intersects said second field of view, said second CMOS chip produces a second digital image comprising a second specific number of pixels, said second camera registering a second sequence of digital images as said specific container passes said second field of view.

16. The apparatus according to claim 14, wherein:

said second camera is electrically connected to said first digital image processing unit.

17. The apparatus according to claim 14, further comprising:

a second digital image processing unit, wherein said second camera is electrically connected to said second digital image processing unit.

18. The apparatus according to claim 16, wherein:

a part of each of said second digital images substantially corresponding to the outline of a specific container is transmitted to said digital image processing unit;

one of said first and said second digital image processing units processes said second sequence of digital images so as to detect said unwanted objects or faults in said specific container;

said processing resulting in either an establishment of an object or fault present or not present in said specific container.

19. The apparatus according to claim 10, wherein:

said path of travel defines an input and a corresponding output, said input receiving said plurality of containers, said output outputting said plurality of containers;

and wherein said apparatus further comprises a return conveyor for conveying specific containers from said output to said input.

20. The apparatus according to claim 19, wherein said return conveyor is selected from the group consisting of at least one of a rotating carrousel, a belt conveyor, a chain conveyor, and a star-wheel.

21. The apparatus according to claim 11, wherein said conveyor includes a carrousel and at least one of said first camera and said second camera is positioned within said carrousel.

22. The apparatus according to claim 20, wherein said conveyor includes a carrousel, and wherein at least one of said first camera and said second camera is positioned within said carrousel.