Method and device for optical examination of transparent bodies

Patent metadata

Field	Value
Publication number	US-11049237-B2
Application number	US-201916264092-A
Country	US
Kind code	B2
Filing date	Jan 31, 2019
Priority date	Aug 1, 2016
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A method and a device for optical examination of transparent bodies made of plastic, glass, or glass ceramic are provided. The examination is carried out by contactless detection and measurement of the body using optical imaging devices. For this purpose, a plurality of individual images are taken of the body during the examination in different positions relative to the imaging device, which are subsequently analyzed.

First claim

What is claimed is:

1. A method for optical examination of transparent bodies, comprising:
a) positioning a transparent body with an area to be examined within a capture range of an imaging device;
b) capturing a first individual image of the body at a first rotational position using the imaging device;
c) transmitting the individual image to a computer unit as a first digital image;
d) rotating the body about an axis to a second rotational position;
e) capturing a second individual image of the body using the imaging device at the second rotational position so that the second individual image at least partially overlaps the first individual image;
f) transmitting the second individual image to the computer unit as a second digital image;
g) controlling the computer unit to computationally compare the first and second images to produce a first difference image;
h) controlling the computer unit to computationally develop the first difference image by cylindrical unfolding to provide a first unfolded difference image;
i) repeating the steps d) through h) until at least one complete revolution of the body has been completed.

2. The method of claim 1 , wherein the body has a rotationally symmetrical shape at least in portions thereof, and wherein the axis of rotation is aligned with the axis of symmetry of the body.

3. The method of claim 1 , wherein the body comprises a material selected from a group consisting of plastic, glass, glass ceramic, and borosilicate glass.

4. The method of claim 1 , wherein the body is selected from a group consisting of a tubular portion, a rod portion, a container, a packaging, a pharmaceutical packaging, a syringe, a cartridge, a vial, and an ampoule.

5. The method of claim 1 , further comprising controlling the computer unit to analyze the difference image by evaluating a lateral offset of a feature in successive images in relation to a rotational velocity of the body.

6. The method of claim 5 , further comprising controlling the computer unit to eliminate, in the difference image, features that are located at the same position in successive images.

7. The method of claim 1 , further comprising controlling the computer unit to eliminate a motion blur in the difference image.

8. The method of claim 1 , wherein the step of rotating the body about the axis comprises rotating by not more than 20°.

9. The method of claim 1 , wherein the rotating and capturing steps are simultaneous.

10. The method of claim 1 , wherein the imaging device comprises a matrix camera or a multi-line camera.

11. The method of claim 1 , further comprising illuminating, using an illumination device, the body during the capturing step.

12. The method of claim 11 , wherein the illumination device comprises a beam source which emits electromagnetic radiation in a visible wavelength range and/or in a near IR wavelength range and/or in a near UV wavelength range.

13. The method of claim 11 , wherein the illumination device comprises a beam source which emits monochromatic radiation.

14. The method of claim 11 , wherein the illumination device comprises a beam source which emits white light.

15. The method of claim 11 , wherein the body is diffusely illuminated.

16. The method of claim 1 , wherein the second individual image overlaps the first individual image by at least 50%.

17. An inspection device for optical examination of a transparent body, comprising:
an optical imaging device, wherein the imaging device has a depth of focus on the body that is a function of a wall thickness of the body, and a ratio of the depth of focus to the wall thickness is less than 5;
a computer unit;
an illumination device for illuminating the body; and
a rotating device for rotating the body, wherein the computer unit is configured to control the imaging device, the illumination device, and the rotating device to:
a) capture a first individual image of the body at a first rotational position using the imaging device;
b) transmit the individual image to the computer unit as a first digital image;
c) rotate the body about an axis to a second rotational position;
d) capture a second individual image of the body using the imaging device at the second rotational position so that the second individual image at least partially overlaps the first individual image.

18. The inspection device of claim 17 , wherein the imaging device has a depth of focus on the body that is at least 1 cm.

19. The inspection device of claim 17 , wherein the imaging device has a depth of focus on the body that is less than 1 cm.

20. The inspection device of claim 17 , wherein the computer unit is further configured to control the imaging device, the illumination device, and the rotating device to:
e) transmit the second individual image to the computer unit as a second digital image;
f) compare the first and second images to produce a first difference image;
g) develop the first difference image by cylindrical unfolding to provide a first unfolded difference image; and
h) repeat the steps c) through g) until at least one complete revolution of the body has been completed.

21. An inspection device for optical examination of a transparent body, comprising:
an optical imaging device;
a computer unit;
an illumination device for illuminating the body; and
a rotating device for rotating the body,
wherein the computer unit is configured to control the imaging device, the illumination device, and the rotating device to:
a) capture a first individual image of the body at a first rotational position using the imaging device;
b) transmit the individual image to the computer unit as a first digital image;
c) rotate the body about an axis to a second rotational position;
d) capture a second individual image of the body using the imaging device at the second rotational position;
e) transmit the second individual image to the computer unit as a second digital image;
f) compare the first and second images to produce a first difference image;
g) develop the first difference image by cylindrical unfolding to provide a first unfolded difference image; and
h) repeat the steps c) through g) until at least one complete revolution of the body has been completed.

Assignees

• Schott Schweiz Ag

Inventors

• Kläger Christian
• Wirth Andreas
• Thürk Jürgen

Classifications

• H04N23/56

  provided with illuminating means · CPC title

• H04N23/90

  Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums · CPC title

• G01B11/24 Primary

  for measuring contours or curvatures · CPC title

• G01N21/90

  in a container or its contents (G01N21/91 takes precedence) · CPC title

• G06T7/571

  from focus · CPC title