DE19650008A1 - Method for optical image analysis for quick detection and classification of defects - Google Patents

Method for optical image analysis for quick detection and classification of defects

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Publication number
DE19650008A1
DE19650008A1 DE1996150008 DE19650008A DE19650008A1 DE 19650008 A1 DE19650008 A1 DE 19650008A1 DE 1996150008 DE1996150008 DE 1996150008 DE 19650008 A DE19650008 A DE 19650008A DE 19650008 A1 DE19650008 A1 DE 19650008A1
Authority
DE
Germany
Prior art keywords
optical
defects
filter
wavelet
image analysis
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
DE1996150008
Other languages
German (de)
Inventor
Heiko Schwarzer
Stephan Teiwes
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BERLINER INST fur OPTIK GmbH
Original Assignee
BERLINER INST fur OPTIK GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BERLINER INST fur OPTIK GmbH filed Critical BERLINER INST fur OPTIK GmbH
Priority to DE1996150008 priority Critical patent/DE19650008A1/en
Publication of DE19650008A1 publication Critical patent/DE19650008A1/en
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/8851—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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/36—Textiles
    • G01N33/367—Fabric or woven textiles

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  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Textile Engineering (AREA)
  • Signal Processing (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)

Abstract

The method involves taking pictures of the surface (1) of products using a CCD camera and processing them in an electronic image processing system (3). Before being processed the image information to be processed is subjected to prefiltering with coherent light (4). The optical prefilter can be a light refracting element acting as a Wavelet filter or wavelet fractional power filter. The optical filter can be an electronic addressable spatial light modulator

Description

Die Erfindung betrifft ein Verfahren und eine Vorrichtung zur optischen Bildanalyse für die schnelle Detektion und Klassifikation von Fehlern in Oberflächenprodukten, insbesondere in Textilgeweben.The invention relates to a method and a device for optical image analysis for the rapid detection and classification of defects in surface products, especially in textile fabrics.

Das bevorzugte Anwendungsgebiet der Erfindung ist die automatisierte Qualitätskontrolle von Textilgeweben und anderen Oberflächen in der industriellen Fertigung.The preferred field of application of the invention is automated Quality control of textile fabrics and other surfaces in industrial Production.

Die automatisierte Qualitätskontrolle von Textilgeweben und anderen Oberflächenprodukten geschieht bisher mit elektronischen Bildverarbeitungssystemen. Dazu werden Bilder von Textilgeweben bewegter Stoffbahnen mit CCD-Kameras aufgezeichnet, einem elektronischen Bildverarbeitungssystem zugeführt und dort ausgewertet.The automated quality control of textile fabrics and others So far, surface products have been done with electronic Image processing systems. Images of textile fabrics are moving Fabric webs recorded with CCD cameras, an electronic one Image processing system fed and evaluated there.

Elektronische Bildverarbeitungssysteme verfügen typischerweise über eine Spezialhardware (elektronischer Signalprozessor) und eine Bildverarbeitungssoftware. Die aufgezeichneten Gewebebilder werden mit digitalen berechneten Bildverarbeitungsoperationen untersucht, die digitale Merkmale liefern, anhand derer gegebenenfalls eine Fehlerdetektion vorgenommen werden kann.Electronic image processing systems typically have one Special hardware (electronic signal processor) and one Image processing software. The recorded tissue images are digital calculated image processing operations that provide digital features, on the basis of which an error detection can be carried out if necessary.

Auf der Basis der aktuell verfügbaren Technologie ist die digitale, rein elektronische Bildverarbeitung für viele Anwendungen, insbesondere für die Qualitätskontrolle strukturierter Textilgewebe zu langsam. Gefordert ist die Verarbeitung von Bildern mit möglichst großer Pixelanzahl und mit Bildraten von mehr als 20-25 Bildern pro Sekunde (Videotakt).Based on the currently available technology, the digital is purely electronic Image processing for many applications, especially for quality control structured textile fabric too slow. The processing of images is also required the largest possible number of pixels and with frame rates of more than 20-25 frames per Second (video clock).

Der Erfindung lag deshalb die Aufgabe zugrunde, die Verarbeitungsgeschwindigkeit zu erhöhen, d. h. mit dem optischen Prozessor mindestens 25 Bilder pro Sekunde zu verarbeiten.The invention was therefore based on the object, the processing speed to increase, d. H. with the optical processor at least 25 frames per second to process.

Diese Aufgabe wird durch ein Verfahren und eine Vorrichtung mit den Merkmalen der Ansprüche 1 und 2 gelöst.This object is achieved by a method and a device with the features of Claims 1 and 2 solved.

Der Anspruch 3 gibt eine zweckmäßige Ausgestaltung der Merkmale im Anspruch 2 wieder.Claim 3 gives an expedient embodiment of the features in claim 2 again.

Ein Ausführungsbeispiel der Erfindung ist in der Abbildung dargestellt und wird im folgenden näher beschrieben.An embodiment of the invention is shown in the figure and is in following described in more detail.

Bilder von Gewebeproben 1 werden mit einer CCD-Kamera aufgezeichnet und über ein elektrisch adressierbares Flüssigkristall-Display 2 in den optischen Prozessor 3 eingegeben. Das Display 2 ist transparent und wird mit einem Laserstrahl 4 durchleuchtet. Auf diese Weise lassen sich Bilder, die im industriellen Prozeß im inkohärenten Licht aufgezeichnet werden, in kohärent beleuchtete Bilder umwandeln. Die kohärente Beleuchtung ist zur kohärenten optischen Filterung erforderlich. Zur optischen Fiterung dient ebenfalls ein adressierbares Flüssigkristall-Display 5. Dieses ist mit einem Computer gekoppelt. Der Computer steuert bzw. programmiert die Filterfunktion des Display 5.Images of tissue samples 1 are recorded with a CCD camera and entered into the optical processor 3 via an electrically addressable liquid crystal display 2 . The display 2 is transparent and is illuminated with a laser beam 4 . In this way, images that are recorded in the industrial process in incoherent light can be converted into coherently illuminated images. Coherent lighting is required for coherent optical filtering. An addressable liquid crystal display 5 also serves for optical filtering. This is coupled to a computer. The computer controls or programs the filter function of the display 5 .

Als optische Filter dienen spezielle Bandpaßfilter (Waveletfilter) sowie Kombinationen dieser Waveletfilter mit sogenannten Korrelationsfiltern (Fractional-Power-Filter), die den Charakteristiken typischer Fehler in Gewebetexturen angepaßt sind.Special bandpass filters (wavelet filters) and combinations serve as optical filters this wavelet filter with so-called correlation filters (fractional power filter), the are adapted to the characteristics of typical defects in fabric textures.

Das Ergebnis der optischen Filterung wird mit einer CCD-Kamera 6 aufgezeichnet und somit werden fehlerhafte Strukturen auf dem gefilterten Bild 7 deutlich hervorgehoben und nichtfehlerhafte Strukturen absorbiert
Mit der optischen Filtertechnik ist es möglich, Defekte in Textilgeweben deutlich sichtbar und damit leicht detektierbar zu machen sowie verschiedene Fehlertypen voneinander zu unterscheiden.The result of the optical filtering is recorded with a CCD camera 6 and thus defective structures are clearly emphasized on the filtered image 7 and non-defective structures are absorbed
With optical filter technology, it is possible to make defects in textile fabrics clearly visible and thus easily detectable, and to differentiate between different types of defects.

Die Verarbeitungsgeschwindigkeit ist durch die Bildrate des Flüssigkristall-Displays 2 zur Bildeingabe beschränkt. Verarbeitungsraten mit der aktuellen Technologie liegen bei 25 Bildern pro Sekunde. Schnellere Displays sind in Entwicklung und werden die Leistung des optischen Prozessors entsprechend erhöhen.The processing speed is limited by the frame rate of the liquid crystal display 2 for image input. Processing rates with the current technology are 25 frames per second. Faster displays are under development and will increase the performance of the optical processor accordingly.

Der optische Prozessor ist flexibel einsetzbar. Durch die Display-Technologie können beliebige Bilder in den Prozessor eingegeben und durch ein steuerbares optisches Filterelement dem Analyseproblem angepaßt und flexibel verarbeitet werden.The optical processor can be used flexibly. Thanks to the display technology any images entered into the processor and through a controllable optical Filter element adapted to the analysis problem and processed flexibly.

Claims (3)

1. Verfahren zur optischen Bildanalyse für die Ermittlung von Fehlern in Oberflächen von Produkten, bei dem durch eine CCD-Kamera Bilder von der Oberfläche aufgezeichnet und in einem elektronischen Bildverarbeitungssystem auswertet werden, dadurch gekennzeichnet, daß die zu analysierende Bildinformation vor einer elektronischen Verarbeitung kohärent-optisch vorgefiltert wird.1. A method for optical image analysis for the determination of defects in surfaces of products, in which images of the surface are recorded by a CCD camera and evaluated in an electronic image processing system, characterized in that the image information to be analyzed is coherently prior to electronic processing. is optically pre-filtered. 2. Vorrichtung zur Durchführung des Verfahrens nach Anspruch 1, dadurch gekennzeichnet, daß als optischer Vorfilter ein diffraktiv wirkendes, d. h. auf Lichtbeugung beruhendes Element vorgesehen ist, das eine Wavelet-Filterung bzw. eine Wavelet-Korrelations­ filterung realisiert.2. Device for carrying out the method according to claim 1, characterized, that as an optical pre-filter a diffractive, d. H. based on light diffraction Element is provided that a wavelet filtering or a wavelet correlation filtering realized. 3. Vorrichtung nach Anspruch 2, dadurch gekennzeichnet, daß das optische Filterelement in Form eines elektronisch adressierbaren räumlichen Lichtmodulators ausgeführt ist.3. Device according to claim 2, characterized, that the optical filter element in the form of an electronically addressable spatial Light modulator is executed.
DE1996150008 1996-11-21 1996-11-21 Method for optical image analysis for quick detection and classification of defects Withdrawn DE19650008A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE1996150008 DE19650008A1 (en) 1996-11-21 1996-11-21 Method for optical image analysis for quick detection and classification of defects

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE1996150008 DE19650008A1 (en) 1996-11-21 1996-11-21 Method for optical image analysis for quick detection and classification of defects

Publications (1)

Publication Number Publication Date
DE19650008A1 true DE19650008A1 (en) 1998-05-28

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2242497A1 (en) * 2003-06-03 2005-11-01 Universitat Politecnica De Catalunya Device for measuring formation in paper using wavelets, has charge coupled device camera catching image of paper illuminated by transmission, and computer analyzing image and utilizing algorithms based on mathematical theory of wavelets
CN109781735A (en) * 2018-12-26 2019-05-21 中电科信息产业有限公司 A kind of quick-fried pearl on-line measuring device and detection method

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2707544C3 (en) * 1976-02-23 1981-01-29 Greenwood Mills, Inc., Greenwood, S.C. (V.St.A.) Coherent scanning device with testing of a surface area of a textile web
EP0704692A1 (en) * 1994-09-27 1996-04-03 Basler GmbH Procedure and device for quality control of an object

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2707544C3 (en) * 1976-02-23 1981-01-29 Greenwood Mills, Inc., Greenwood, S.C. (V.St.A.) Coherent scanning device with testing of a surface area of a textile web
EP0704692A1 (en) * 1994-09-27 1996-04-03 Basler GmbH Procedure and device for quality control of an object

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2242497A1 (en) * 2003-06-03 2005-11-01 Universitat Politecnica De Catalunya Device for measuring formation in paper using wavelets, has charge coupled device camera catching image of paper illuminated by transmission, and computer analyzing image and utilizing algorithms based on mathematical theory of wavelets
CN109781735A (en) * 2018-12-26 2019-05-21 中电科信息产业有限公司 A kind of quick-fried pearl on-line measuring device and detection method

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