System and method for detecting flaws in continuous web materials

• US 5,068,799 A
• Filed: 04/24/1985
• Issued: 11/26/1991
• Est. Priority Date: 04/24/1985
• Status: Expired due to Fees

• Current Assignee: Georgia Gulf Corporation
• Original Assignee: Georgia Gulf Corporation
• Inventors: Jarrett, Harold M. Jr.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): TRANS, VINCENT N
• Application Number:
  US06/726,529
• Time in Patent Office: 2,407 Days
• Field of Search: 364/507, 364/900, 364/551, 364/552, 364/570, 364/572, 364/724, 364/726, 324/238, 324/240, 356/429, 356/430, 356/431, 356/237, 356/238, 356/239, 382/30, 382/31
• US Class Current: 702/40
• CPC Class Codes: G01N 2021/8887 based on image processing techniques
• CPC Class Codes: G01N 21/89 in moving material, e.g. running paper or textiles G01N21/90, G01N21/91, G01N21/94 take precedence
• CPC Class Codes: G01N 2201/102 Video camera
• CPC Class Codes: G06T 2207/20076 Probabilistic image processing
• CPC Class Codes: G06T 2207/30124 Fabrics; Textile; Paper
• CPC Class Codes: G06T 7/0004 Industrial image inspection

Abstract

A method and apparatus for detecting flaws in continuous web material illuminated by a light source and optically scanned to produce a digitalized electronic image of said material. The digitized image data representative of the continuous web material is stored in memory. The image data is also applied to a digital signal processor which identifies areas of the image which represent potential flawed areas of the continuous web material. A variety of spatial matched filters are employed to detect the flaws. Information concerning the locations of the potential flaws is transferred to a computer which analyzes in detail portions of the stored image in the vicinity of the identified areas. The processing performed in the computer verifies the presence of flaws in the material.

Claims

1. A method of detecting flaws in continuous web material which is illuminated and which is scanned by an optical scanning system to produce digitized output signals representative of said material, said method comprising the steps of:

processing said digitized output signals utilizing digital matched filters corresponding to flaw patterns known to be present in said material to identify signals present therein which are representative of flaws in said material; and

generating first output signals indicative of the locations of said flaws in said material.

2. The method of claim 1 which further comprises the step of:

processing said digitized output signals utilizing information contained in said first output signals which is indicative of potential flaw locations; and

verifying the existence of flaws at said identified locations.

3. The method of claim 1 which further comprises the steps of:

storing said digital output signals; and

processing said stored signals and said first output signals to verify the existence of flaws in said material corresponding to locations in a memory which contain data representing potential flaws.

4. A method of detecting flaws in continuous web material which is illuminated and which is scanned by an optical scanning system to produce digitized output signals representative of said material, said method comprising the steps of:

applying said digitized output signals representative of said material to a digital signal processor;

storing said digitized output signals in a memory;

processing said digitized output signals in said digital signal processor by means of digital matched filters corresponding to flaw patterns known to be present in said material to identify locations in said memory which contain data representing potential flaws; and

processing signals stored in said memory and signals which have been identified by said digital signal processor as containing data representing potential flaws in said computer to verify the existence of flaws at those locations.

5. A method of detecting flaws in continuous web material which is illuminated and which is scanned by an optical scanning system to produce digitized output signals representative of said material, said method comprising the steps of:

storing said digitized output signals in a memory;

analyzing said digitized output signals by means of predetermined digital matched filters corresponding to predetermined flaw types to provide first output signals indicative of the locations of potential flaws in said material;

analyzing in detail said stored digitized output signals at locations indicated by said first output signals to identify and classify actual flaws present at said locations in said material.

6. The method of claim 5 wherein the first analyzing step further comprises:

analyzing unflawed material by means of said matched filters to provide calibration signals corresponding to each point in said material; and

comparing output signals from said matched filters to said calibration signals to identify points in said stored image which correspond to potential flaws.

7. A system for detecting flaws in continuous web material which is illuminated and which is scanned by an optical scanning system to produce digitized output signals representative of said material, said system comprising:

digital signal processing means comprising digital matched filters corresponding to flaw patterns known to be present in said material coupled to said optical scanning system for processing said digitized output signals utilizing said matched filters to identify signals present therein which are representative of flaws in said material, and for providing output signals indicative of the locations of said flaws in said material.

8. The system of claim 7 which further comprises:

microprocessor means coupled to said digital signal processing means for process said digitized output signals utilizing information contained in said output signals which is indicative of potential flaw locations, an for verifying the existence of flaws at said identified locations.

9. The system of claim 7 which further comprises:

microprocessor means, including memory means for storing said digitized output signals, coupled to said digital signal processing means for storing said digital output signals and for processing said stored signals and information contained in said output signals which are indicative of locations in said memory which contain data representing potential flaws, and for verifying the existence of flaws in said material corresponding to said identified memory locations.

10. A system for detecting flaws in continuous web material which is illuminated and which is scanned by an optical scanning system to produce digitized output signals representative of said material, said system comprising:

memory means for storing said digitized output signals;

digital signal processing means for processing applied digitized output signals by means of digital matched filters corresponding to flaw patterns known to be present in said material to identify locations in said memory which contain data representing potential flaws;

controller means for transferring said digitized output signals to said memory and to said digital signal processor; and

computer means, for processing signals stored in said memory means in accordance with output signals derived form said digital signal processing means which are indicative of locations in said memory which contain data representing potential flaws, and for verifying the existence of flaws at said identified memory locations.

11. A method of detecting flaws in continuous web material which is illuminated and which is scanned by an optical scanning system to produce digitized output signals representative of said material, said method comprising the steps of:

analyzing unflawed material by means of digital matched filters to provide calibration signals corresponding to said unflawed material;

storing said calibration signals in a first portion of a memory;

storing said digitized output signals in a second portion of said memory;

processing said digitized output signals by means of said digital matched filters to generate flaw location signals indicative of potential flaws locations in said material; and

processing said digitized output signals stored in said second portion of said memory and said calibration signals stored in said first portion of said memory by means of a computer in regions surrounding said potential flaw locations by comparing said digitized output signals to said calibration signals in order to verify the existence of flaws at those locations.

12. A method of detecting flaws in continuous web material which is illuminated an which is scanned by an optical scanning system to produce digitized output signals representative of said material, said method comprising the steps of:

analyzing unflawed material by means of digital matched filters corresponding to predetermined flaw types to provide calibration signals corresponding to said material;

storing said calibration signals in memory;

analyzing said digitized output signals by means of said digital matched filters to provide first output signals;

comparing said first output signals to said calibration signals to identify locations in said material which correspond to potential flaws; and

re-analyzing said digitized output signals at said identified locations to verify and classify actual flaws present at said locations in said material.

13. A system for detecting flaws in continuous web material which is illuminated and which is scanned by an optical scanning system to produce digitized output signals representative of said material, said system comprising:

digital signal processing means comprising predetermined digital matched filters coupled to said optical scanning system for processing said digitized output signals utilizing said filters to identify signals present therein which are representative of flaws in said material, and for providing output signals indicative of the locations of said flaws in said material; and

microprocessor means coupled to said digital signal processing means for processing said digitized output signals utilizing information contained in said output signals which is indicative of potential flaw locations, and for verifying the existence of flaws at said identified locations.

14. A system for detecting flaws in continuous web material which is illuminated an which is scanned by an optical scanning system to produce digitized output signals representative of said material, said system comprising:

digital signal processing means comprising predetermined digital matched filters coupled to said optical scanning system for processing said digitized output signals utilizing said filters to identify signals present therein which are representative of flaws in said material, and for providing output signals indicative of the locations of said flaws in said material; and

microprocessor means, including memory means for storing said digitized output signals, coupled to said digital signal processing means for storing said digital output signals and for processing said stored signals and information contained in said output signals which are indicative of locations in said memory which contain data representing potential flaws, and for verifying the existence of flaws in said material corresponding to said identified memory locations.

15. A system for detecting flaws in continuous web material which is illuminated an which is scanned by an optical scanning system to produce digitized output signals representative of said material, said system comprising:

digital signal processing means comprising digital matched filters for processing unflawed material to provide calibration signals corresponding thereto and for processing said digitized output signals to generate flaw location signals indicative of potential flaw locations in said continuous web material;

first memory means for storing said calibration signals;

second memory means for storing said digitized output signals; and

computer means for processing said digitized output signals stored in said second memory means in regions surrounding said potential flaw locations by comparing said digitized output signals to said calibration signals in order to verify the existence of flaws at those locations.