Web inspection system and method therefor

• US 4,173,441 A
• Filed: 03/28/1977
• Issued: 11/06/1979
• Est. Priority Date: 03/28/1977
• Status: Expired due to Term

• Current Assignee: Van Dorn Co. (Crown Holdings Incorporated)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Wolf, William E.
• Primary Examiner(s): McGraw, Vincent P.
• Application Number:
  US05/781,879
• Time in Patent Office: 953 Days
• Field of Search: 356/200, 356/430, 356/431, 250/563
• US Class Current: 356/431
• CPC Class Codes: G01N 21/8915 non-woven textile material

Abstract

An inspection system for web materials, including electronic means responsive to means scanning the web for detecting a plurality of nonuniform appearance features of the web; means for discriminating these appearance features as to class to identify the significant electrical signal components thereof; means for electrically dividing the web into overlapping areas; means for counting the number of occurrences of the significant signal components over a series of scans within each of the overlapping areas; means for comparing each count with predetermined values to electrically define nonuniform appearance features according to area; and means for combining these nonuniform appearance features to recognize the occurrence of a visual defect class as it occurs within each overlapping area.

Claims

1. An inspection system for web materials that includes electronic means responsive to means scanning the web for detecting a plurality of different nonuniform appearance features of the web, said electronic means comprising:

means for electrically discriminating said appearance features as to a predefined class to identify the significant electrical signal components thereof;

means for electrically dividing the web into frames;

means for counting the number of occurrences of said significant signal components over a series of scans within each of said frames;

means for comparing each count of the number of occurrences of said significant signal components within each frame with predetermined values to electrically define nonuniform appearance features according to frame; and

means for combining said electrically defined nonuniform features to recognize the occurrence of a visual defect class as it occurs within each said scanned frame.

2. In an inspection system for web materials that includes electronic means responsive to means scanning the web for detecting a preselected plurality of different nonuniform appearance features of the web to form an extracted single-scan feature set, the improvement comprising:

circuit means for dividing the web into separate but overlapping frames aligned in the web motion direction and transverse thereto;

circuit means to accumulate in separate sums the respective values of the extracted single-scan features of said preselected plurality occurring in each said overlapping frame;

means for discriminating said separate sums;

means for composing respective binary lane feature status words from said discriminated sums, wherein each status word has a bit position assignment corresponding to the lane in which a significant appearance feature occurs;

means for combining according to lane the bits of said lane feature status words into a predetermined logic statement, said logic statement defining a distinctive defect class; and

means for determining the presence of said defect class according to the resultant truth value of said logic statement pertaining to each said frame.

3. In a method of inspecting a web that includes electro-optically scanning the web and generating electrical output signals representative of different nonuniform appearance features of the web and discriminating said output signals to form signals representing extracted single-scan features, the improvement comprising:

electrically dividing the web into separate overlapping frames;

accumulating in separate sums the respective values of said extracted single-scan features in each said overlapping frame;

discriminating said separate sums to form binary lane feature status words;

combining the bits of said lane feature status words into a predetermined logic statement, said logic statement defining a distinctive defect class; and

determining the presence of said defect class according to the resultant truth value of said logic statement pertaining to each said frame.