Method for checking an image inspection system

Patent metadata

Field	Value
Publication number	US-9953435-B2
Application number	US-201615378315-A
Country	US
Kind code	B2
Filing date	Dec 14, 2016
Priority date	Dec 15, 2015
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A method is provided for checking an image inspection system having a camera system with a camera, an illumination apparatus for targeted illumination of a printing substrate, an image processing computer, and a main computer, for quality control of products of a printing substrate processing machine by using the main computer. A reference image is entered and transmitted to the main computer, a current printing image recorded by the camera system is transmitted to the image processing computer, a partial image in a suitable region of the current printing image, not being printed with printing image data, is selected in the image processing computer, the partial image is analyzed by comparison with the reference image in the image processing computer, and the inspection system is assessed based on the analysis of the partial image by the main computer and any defects of the inspection system being found are indicated.

First claim

The invention claimed is:

1. A method for checking an image inspection system used in printing technology, the method comprising the following steps:
providing a camera system having at least one camera, an illumination apparatus for a targeted illumination of a printing substrate, an image processing computer, and a main computer, for quality control of products of a printing substrate processing machine by using the main computer;
using the printing technology inspection system to check printed products being produced in a printing machine for possible errors as part of a performance of a printing application, by:
entering a reference image and transmitting the reference image to the main computer;
using the camera system to record a current printing image and transmitting the current printing image to the image processing computer;
using the image processing computer to select at least one partial image in a suitable region not being printed with printing image data in the current printing image;
analyzing the at least one partial image by comparison with the reference image in the image processing computer by applying statistical methods to a contrast profile; and
using the main computer to assess the inspection system based on a result of the analysis of the at least one partial image, to indicate any defects found in the inspection system and to eliminate found defects in the inspection system to ensure a quality check of printed printing products.

2. The method according to claim 1 , which further comprises carrying out the assessment of the inspection system with respect to potential error sources selected from the group consisting of an alignment of the at least one camera, a state of the illumination, a soiling of a lens of the at least one camera and a calibration of the inspection system.

3. The method according to claim 1 , which further comprises at least one of:
displaying the defects being found on a screen connected to the main computer, or
capturing the defects being found in a protocol stored in a memory connected to the main computer.

4. The method according to claim 3 , which further comprises connecting the main computer to a network for remote data transmission, and transmitting the protocol from the main computer to a remote service computer.

5. The method according to claim 1 , which further comprises selecting the printed areas containing no printing image data as at least one of color measurement fields or registration marks or non-printed areas.

6. The method according to claim 1 , wherein the image inspection system is integrated in a sheet-fed printing machine for carrying out a method for in-line image inspection.

7. The method according to claim 6 , which further comprises using non-printed areas of a current printing image at least at one of gripper bars or a rear sheet edge as suitable regions.

8. The method according to claim 1 , wherein the image inspection system is integrated in a sheet-fed printing machine selected from the group consisting of a sheet-fed offset printing machine, a sheet-fed inkjet printing machine and a sheet-fed toner printing machine, for carrying out a method for in-line image inspection.

9. The method according to claim 1 , wherein the image inspection system is integrated in a web printing machine, for carrying out a method for in-line image inspection.

10. The method according to claim 1 , wherein the image inspection system is integrated in a web printing machine selected from the group consisting of a web offset printing machine, a web inkjet printing machine and a web toner printing machine, for carrying out a method for in-line image inspection.

11. The method according to claim 1 , which further comprises carrying out the method as an automated method performed as part of or parallel to the inspection method at regular intervals.

Assignees

• Heidelberger Druckmasch Ag

Inventors

• Fergen Immanuel
• Soltwedel Frank
• Schumann Frank

Classifications

• G06T7/80 Primary

  Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration · CPC title

• H04N1/0057

  Conveying sheets before or after scanning (arrangements for conveying sheets as part of the scanning operation H04N1/04 and subgroups) · CPC title

• H04N1/00665

  Details specific to handling of web-shaped media, e.g. paper or film rolls · CPC title

• H04N2201/0084

  Digital still camera · CPC title

• B41F33/0036 Primary

  Devices for scanning or checking the printed matter for quality control · CPC title