JPS5474792A - Surface defect inspection method of steel plates - Google Patents

Surface defect inspection method of steel plates

Info

Publication number
JPS5474792A
JPS5474792A JP14251577A JP14251577A JPS5474792A JP S5474792 A JPS5474792 A JP S5474792A JP 14251577 A JP14251577 A JP 14251577A JP 14251577 A JP14251577 A JP 14251577A JP S5474792 A JPS5474792 A JP S5474792A
Authority
JP
Japan
Prior art keywords
defect
image
signal processing
processing part
signal
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.)
Granted
Application number
JP14251577A
Other languages
Japanese (ja)
Other versions
JPS6142221B2 (en
Inventor
Takeshi Katayama
Kenichi Sakamoto
Tadao Kawaguchi
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.)
Nippon Steel Corp
Original Assignee
Nippon Steel Corp
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 Nippon Steel Corp filed Critical Nippon Steel Corp
Priority to JP14251577A priority Critical patent/JPS5474792A/en
Publication of JPS5474792A publication Critical patent/JPS5474792A/en
Publication of JPS6142221B2 publication Critical patent/JPS6142221B2/ja
Granted legal-status Critical Current

Links

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
    • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles

Landscapes

  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)

Abstract

PURPOSE:To identify the kinds of defects and perform judgement of defect harmful rate by considering power spectrum distribution in frequency space. CONSTITUTION:The image of a defect is formed in an image pickup part 45 by an optical system 44 and is converted to an electric signal 4a which is then sent to a signal processing part 46. In the signal processing part 46, it undergoes necessary preprocessing such as mean value, trend removal, etc. for the defect image information, after which two-dimensional Fourier transformation processing is accomplished. The output 4b of the signal processing part 46 is the frequency space image corresponding to the defect image and the characteristic parameters DFw, DFr, Rw, Rr having beforehand been selected based on this two-dimensional spectrum distribution pattern are operated. The signal 4c of the magnitude thereof is then outputted to respective level discrimination parts 48. In a defect judgement part 49, the kind and size of the defect are judged from the mutual relationship of the levels of the respective parameters.
JP14251577A 1977-11-28 1977-11-28 Surface defect inspection method of steel plates Granted JPS5474792A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP14251577A JPS5474792A (en) 1977-11-28 1977-11-28 Surface defect inspection method of steel plates

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14251577A JPS5474792A (en) 1977-11-28 1977-11-28 Surface defect inspection method of steel plates

Publications (2)

Publication Number Publication Date
JPS5474792A true JPS5474792A (en) 1979-06-15
JPS6142221B2 JPS6142221B2 (en) 1986-09-19

Family

ID=15317140

Family Applications (1)

Application Number Title Priority Date Filing Date
JP14251577A Granted JPS5474792A (en) 1977-11-28 1977-11-28 Surface defect inspection method of steel plates

Country Status (1)

Country Link
JP (1) JPS5474792A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5754844A (en) * 1980-09-19 1982-04-01 Nippon Steel Corp Flaw signal processing apparatus
US5533139A (en) * 1992-05-29 1996-07-02 Eastman Kodak Company Coating density analyzer and method using image processing

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6314021U (en) * 1986-07-14 1988-01-29
JPS6314020U (en) * 1986-07-14 1988-01-29
JPS6314019U (en) * 1986-07-14 1988-01-29

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5059081A (en) * 1973-09-26 1975-05-22
JPS5080885A (en) * 1973-11-15 1975-07-01
US3944978A (en) * 1974-09-09 1976-03-16 Recognition Systems, Inc. Electro-optical method and apparatus for making identifications
JPS51145387A (en) * 1975-06-10 1976-12-14 Toshiba Corp Fault detecting device
JPS5292579A (en) * 1976-01-28 1977-08-04 Toyo Boseki Method of discriminating defects of sheet

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5059081A (en) * 1973-09-26 1975-05-22
JPS5080885A (en) * 1973-11-15 1975-07-01
US3944978A (en) * 1974-09-09 1976-03-16 Recognition Systems, Inc. Electro-optical method and apparatus for making identifications
JPS51145387A (en) * 1975-06-10 1976-12-14 Toshiba Corp Fault detecting device
JPS5292579A (en) * 1976-01-28 1977-08-04 Toyo Boseki Method of discriminating defects of sheet

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5754844A (en) * 1980-09-19 1982-04-01 Nippon Steel Corp Flaw signal processing apparatus
US5533139A (en) * 1992-05-29 1996-07-02 Eastman Kodak Company Coating density analyzer and method using image processing

Also Published As

Publication number Publication date
JPS6142221B2 (en) 1986-09-19

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