Machine for inspecting glass containers

• US 8,135,206 B2
• Filed: 05/02/2007
• Issued: 03/13/2012
• Est. Priority Date: 05/02/2007
• Status: Expired due to Fees

• Current Assignee: Applied Vision Corporation (Antares Vision S.p.A.), Applied Vision Corporation LLC, Emhart Glass SA (Bucher Industries AG)
• Original Assignee: Emhart Glass SA (Bucher Industries AG)
• Inventors: Sones, Richard A., Diehr, Richard D., Novini, Amir R.
• Primary Examiner(s): ZARKA, DAVID PETER
• Application Number:
  US11/799,656
• Publication Number:
  US 20080273086A1
• Time in Patent Office: 1,777 Days
• Field of Search: 382/142
• US Class Current: 382/142
• CPC Class Codes: G01N 21/90 in a container or its contents G01N21/91 takes precedence
• CPC Class Codes: G01N 21/9054 Inspection of sealing surface and container finish
• CPC Class Codes: G06T 2207/30108 Industrial image inspection
• CPC Class Codes: G06T 7/0004 Industrial image inspection

Abstract

A machine for inspecting glass containers rotating at an inspection station. A camera images an area of interest on the glass container (the finish for example) and the area is imaged at angular increments. An anomalous object is analyzed in each image and the deviation of its center relative to a datum is measured. A deviation less than a maximum enables the control to identify the object as a blister.

Claims

1. A machine for inspecting a finish portion of a glass container at an inspection station for defects, comprising:

a rotation mechanism configured to rotate a glass container about an axis of rotation of the glass container at the inspection station,

a light source operable to illuminate the finish portion of the rotating glass container,

a camera operable to image the selected illuminated finish portion of the glass container,

said camera viewing the finish portion at an acute angle to the glass container axis of rotation;

a control which is configured

to control the operation of said camera to capture an image at a predetermined number of angular increments of rotation whereby objects, corresponding to reflections from a defect in the finish portion, in the images captured at the predetermined number of angular increments will follow an elliptical path,

to locate the edge of the finish of the glass container and to shift at least one of the imaged objects to the captured images of the objects based on the location of the edge of the finish of the glass container; and

to evaluate the objects based on their locations relative to a straight datum.

2. The machine of claim 1, wherein the light source is defined by a pair of conical light sources having light axes which are horizontal and 90 degrees related and substantially coplanar with the uppermost portion of the finish portion of the glass container, and said camera has an axis 45 degrees from the horizontal plane of the uppermost portion of the finish portion of the glass container and bisecting said horizontal light axes.

3. The machine of claim 1, wherein the image captured by the camera is defined by an X-Y array of pixels and wherein said control configured to unwrap the images captured at the predetermined number of angular increments is configured to:

fit a curve to points of the located edge,

determine the peak of the fitted curve,

define a line tangentially related to the peak, and

to shift the pixels in each vertical column by the number of pixel difference between the fitted curve and the peak tangent line.

4. A machine for inspecting a finish portion of a glass container at an inspection station for defects, comprising:

a rotation mechanism configured to rotate the glass container about its vertical axis;

a light source;

a camera directed towards the finish portion, the light source and the camera being arranged and configured such that the camera images an anomaly comprising a reflection from the defect of light from the light source; and

a control configured to image at least a portion of the finish portion at a plurality of angular increments of rotation, an anomaly being captured in the image following an elliptical path over the predetermined number of angular increments of rotation, the control further configured to unwrap the image and to evaluate the anomaly;

wherein the light source comprises a pair of light sources having light axes which are arranged and configured in a horizontal plane, forming between them a 90 degree angle, the finish portion of the glass container being disposed in the horizontal plane, and wherein said camera includes an imaging axis forming a 45 degree angle with the horizontal plane.

5. The machine of claim 4, wherein the control is configured to image at least a portion of the finish portion at the plurality of angular increments of rotation by one of holding the camera open while strobing the light source at each of the plurality of angular increments of rotation and operating the camera at each of the angular increments of rotation.

6. The machine of claim 4, wherein the control is configured to locate the upper edge of the finish of the container, to define a curve proportional to the upper edge of the finish of the container, and to define a line tangentially related to the maximum of the curve.

7. The machine of claim 6, wherein the image comprises a plurality of columns of pixels;

and

wherein the control is configured to determine the distance between the curve and the line for each column of pixels and, for each column, to shift the pixels below the curve vertically by the distance between the curve and the line to unwrap the image.

8. The machine of claim 4, wherein the imaging axis bisects the light axes, forming a 45 degree angle with each.

9. The machine of claim 4, wherein the control is configured to define a plurality of horizontal bands and to evaluate the anomaly relative to the horizontal bands.

10. The machine of claim 9, wherein a dimension of each horizontal band is settable.

11. The machine of claim 9, wherein the control is configured to determine the appearances of the anomaly in each band to define a cluster.

12. The machine of claim 11, wherein the control is configured to determine whether the cluster has a gap a predetermined distance wide.

13. The machine of claim 12, wherein the predetermined distance is settable, and where at least one of the type and number of defects in the bottle may be determined based on the size of a gap in a cluster.

14. A machine for inspecting a finish portion of a glass container at an inspection station for defects, comprising:

a rotation mechanism configured to rotate the glass container about its vertical axis;

a light source;

a camera directed towards the finish portion, the light source and the camera being arranged and configured such that the camera images an anomaly comprising a reflection from the defect of light from the light source; and

a control configured to image at least a portion of the finish portion at a plurality of angular increments of rotation, an anomaly being captured in the image following an elliptical path over the predetermined number of angular increments of rotation, the control further configured to unwrap the image and to evaluate the anomaly;

wherein the control is configured to define a plurality of horizontal bands and to evaluate the anomaly relative to the horizontal bands;

wherein the control is configured to determine the appearances of the anomaly in each band to define a cluster; and

wherein the control is configured to determine whether the cluster has a gap a predetermined distance wide.

15. The machine of claim 14, wherein the light source comprises a pair of light sources having light axes which are arranged and configured in a horizontal plane, forming between them a 90 degree angle, the finish portion of the glass container being disposed in the horizontal plane, and wherein said camera includes an imaging axis forming a 45 degree angle with the horizontal plane.

16. The machine of claim 14, wherein the control is configured to image at least a portion of the finish portion at the plurality of angular increments of rotation by one of holding the camera open while strobing the light source at each of the plurality of angular increments of rotation and operating the camera at each of the angular increments of rotation.