Heidelberger Druckmaschinen Ag

Gretag-macbeth Ag

Frank Schumann

Wolfgang Geissler

Frank Soltwedel

Christopher Riegel

Immanuel Fergen

Jan Krieger

Stephan Rudzewitz

Peter Ehbets

Manfred Schneider

Thomas Wolf

Frank Muth

Peter Eisele

Robert Lange

Loris De Vries

Werner Huber

Harald Bucher

Michael Kaiser

Peter Elter

Hans Engler

Winfried Berg

Michael Krüger

Robert Mueller

J&uuml;rgen Rautert

Sascha Epp

Bennet Carstensen

Hendrik Schmedt

Daniel Blatt

Karl Wispeintner

Volker Felzen

A method of controlling the quality of printed products by using a computer includes always producing multiple printed products with at least partially identical image content in a printing machine in a course of a print job to be completed. The multiple printed products are recorded by at least one image sensor and are sent to the computer as digital image data. The computer examines and assesses the digital image data in an image inspection process to find print defects and to sort out printed products that have been found to be unusable. The computer assesses the identical image content of the digital image data of at least two consecutive printed products and only takes into consideration such detected print defects that are present on the at least two assessed consecutive printed products.

Method of controlling the quality of printed products by image inspection filtering

A method for determining print defects in a printing operation carried out on an inkjet printing machine for processing a print job includes using a camera system to record and digitize printed products generated during the printing operation, feeding the camera image having been thus generated to a detection algorithm on the computer, alerting a machine control unit when print defects are found, and ejecting the printed product through a waste ejector if necessary. The detection algorithm separates color separations of the camera images, detects the print defects in the color separations, links images of the individual color separations to form a candidate image, filters the candidate image, enters the remaining detected print defects into a list, and forwards the list to the machine control unit of the printing machine.

Method for determining print defects in a printing operation carried out on an inkjet printing machine for processing a print job

A method of inspecting images on printed products by a computer in a printing machine. Printed products are recorded and digitized by an image sensor of an image inspection system in the course of the image inspection process, and the computer compares them to a digital reference image. If deviations are found, the defective printed products are removed. The computer analyzes the deviations found in the course of the image inspection process together with further data from other system parts and from the machine, determines specific defect classes and the causes thereof based on the defects by machine learning processes, assigns the defects found in the image inspection process to the defect classes in a corresponding way, and displays the classified detected defects with their defect classes and causes to an operator of the machine so that the operator can initiate specific measures to eliminate the defect causes.

Printed image inspection method with defect classification

A method for inspecting printed products of a machine for processing printing substrates includes recording and digitizing produced printed products by using at least one image sensor and analyzing the printed products by using a computer to find potential defects. Defects in the printed products are detected by the computer by comparing the recorded and digitized printed image with a digital reference image, analyzing occurring deviations, and marking defective printed products in a manner suitable for removal. The computer spatially subdivides every digitized printed image into regions with deviations, calculates the time required to analyze every one of the regions, and terminates the analysis of a digitized printed image when the time required to analyze the regions exceeds a predefined value of time per digitized printed image.

Method for deterministic image inspection of printed products of a machine for processing printing substrates

A method for image inspection on printed products in a printing material processing machine. Printed products are recorded and digitizing and the recorded images are compared with a digital reference image to find image areas with distorted regions. Suitable rectification factors are calculated and the digital reference image is rectified with suitable rectification factors for the distorted image areas. The modified digital reference image is then compared to images recorded during the production run. If deviations are found, the printed products are found defective and removed. The computer also identifies image areas in the reference image that do not have enough edges for calculating suitable rectification factors and inserts anchors into the image areas. The anchors are printed, recorded and digitized, as they become part of the recorded digital printed image. In that case, the computer calculates the local rectification factors by way of the anchors.

Image inspection method with local image rectification

A method for inspecting images on printed products in a machine for processing printing substrates includes recording and digitizing the produced printed products by using at least one image sensor in an image recording system, comparing the recorded digital printed images having been created in this way with a digital reference image by using the computer, digitally eliminating distortion in the recorded digital printed images beforehand by using the computer and, if the recorded digital distortion-free printed images deviate from the digital reference image, removing printed products having been found to have a defect. For the purpose of digitally eliminating the distortions, the computer divides the print and reference images into respective image parts and adapts the printed image parts pixel by pixel in terms of their positions in the printed image to minimize the difference between the printed image parts and the respective reference image parts.

Method for fast elimination of image distortions while inspecting images on printed products in a printing machine

A method for image inspection of printed products in a printing material processing machine includes using an image sensor to capture and digitize printed products during image inspection by an image capture system, using a computer to carry out a comparison of captured digital printed images with a digital reference image, examining a result of the comparison for image regions with blurry regions in the captured digital printed image, calculating suitable smoothing factors for the blurry image regions, and then carry out smoothing of the digital reference image with the calculated, suitable smoothing factors for the blurry image regions, causing the digital reference image to have a blurriness comparable to the captured digital printed image in the image regions. Printed products detected as faulty are removed upon an occurrence of deviations of the captured digital printed image from the digital reference image.

Method for image inspection of printed products using adaptive image smoothing

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.

Method for checking an image inspection system

A digital image inspection method checks printing material processing machine products by recording digital printed partial images using recording devices and combining partial images in an image processing computer forming a digital overall image causing abutment edges at an overlap. The computer inspects the digital overall image and transmits a result to a machine control computer. The computer creates a new image, only containing detected edges, using edge detection methods after combining partial images forming a digital overall image. The computer uses known positions of abutment edges of recording devices to create a further new image only containing regions with abutment edges of recording devices. The computer overlays the new images, providing a resultant image containing only edges along abutment edges of recording devices. The computer applies the resultant image to the digital overall image, defining masking zones in the resultant digital overall image not being checked by image inspection.

Image inspection method with a plurality of cameras

A method for testing the reliability of an error detection of an image inspection method by using a computer includes producing a defective test image by superposing specific error elements on an error-free reference image, carrying out the image inspection method with the defective test image, comparing the errors found by the image inspection method with the error set to be expected with the aid of the known errors added to the test image, and evaluating the reliability of the image inspection method with the aid of the difference between found and expected errors.

Method for testing the reliability of error detection of an image inspection method

A method for automatically selecting test parameters for an image inspection system using a computer, includes digitizing a reference image or a scanned printed image to determine target values, categorizing the image elements that are present, determining tolerances for the target values based on the categorization, calculating the inspection sensitivity based on target values and the respective tolerances thereof, setting the parameters of the image inspection system based on the inspection sensitivity, and configuring the image inspection using these parameters. An image inspection system for implementing the method is also provided.

Method for automatically selecting test parameters of an image inspection system and image inspection system for implementing the method

An apparatus and a method for evaluating control marks on printing materials by an optical sensor connected to a computer, which interprets overshooting of a predefined intensity threshold as it registers the printing material being a line of a printed control mark. The apparatus is distinguished by the fact that the control mark is registered by a color measuring instrument and that the intensity threshold of the optical sensor is calculated by the computer in dependence on the measured color value registered by the color measuring instrument.

Optimized-intensity control mark measurement and apparatus for performing the measurement

An apparatus in a machine for processing printing material has a register sensor for register measurement between at least two color separations of a printed image printed above one another on a printing material. The register sensor registers optically deviations between the two color separations and forwards the deviations onto a computer. The register sensor contains at least one photodiode having at least two quadrants. The largely rectangular evaluation areas of the photodiode are aligned obliquely in relation to the edges of the conveyed printing material. A register mark to be detected by the register sensor has a plurality of wedge-shaped colored areas pointing in a peripheral direction of the printing material, one of the wedge-shaped colored areas being a reference color used as a reference variable and others of the wedge-shaped colored areas being register colors to be controlled. An alternative register mark has a first field for length calibration; a second field having a wedge of a reference color selected as a reference variable; and a third field containing a register color to be controlled. The may also be provided a measuring field formed as a point-symmetrical field exhibiting a color of a color separation as a full tone.

Register mark to be detected by a register sensor

A measuring apparatus for scanning moving, preferably sheet-like, printing materials in a printing material-processing machine, such as a press for processing sheet material. The apparatus has a measuring device which can be moved, at least in the transport direction of the printing materials. The measuring apparatus is set up in such a way that, during a measuring operation, the measuring device is moved over the moving printing material in the transport direction of the printing material with a differential speed relative to the transport speed of the printing material.

Measuring apparatus having a movable measuring device in a press

An apparatus in a machine for processing printing material has a register sensor for register measurement between at least two color separations of a printed image printed above one another on a printing material. The register sensor registers optically deviations between two color separations lying one above the other on the printing material and forwards the deviations onto a computer. The apparatus includes register marks to be measured by the apparatus. The apparatus is distinguished in that the register sensor contains at least one photodiode having at least two quadrants, and in that the largely rectangular evaluation areas of the photodiode are aligned obliquely in relation to the edges of the conveyed printing material.

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Heidelberg, Germany

Frank Schumann