US3779649A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and an electro-optical system for inspecting material
Assignee: SIRA INST GB
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Filing: 1971-12-10
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Granted: 1973-12-18
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Expires: 1991-12-10
Abstract
Abstract A method of, and system for, automatically inspecting a surface of material such as strip or sheet metal in order to detect flaws in the surface. The surface is moved beneath an optical scanner which receives light reflected from sequential parts of said surface. The reflected light is converted in an electrical waveform composed of a series of pedestals each corresponding to the reflectivity of a part of the surface representing one scan. An analogue comparison waveform is derived from each of the pedestals, by inter alia a special filtering operation and this waveform provides a reference by which the pedestals are examined for flaw indicative information. Various techniques are employed to assess the quality of the pedestals and to generally improve the validity of the flaw detecting operation.
Inventors
- 👤 H Bertoya
- 👤 D Ross
- 👤 R Brook
- 👤 A Allnutt
- 👤 R Semos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:05
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/89
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
86 words
In a system for inspecting material having means for collecting electromagnetic radiation influenced by the presence of said material and means for producing a first electrical waveform dependent on said collected radiation the improvement comprising: means for deriving a second electrical waveform having the same general shape as that of the first waveform but modified in respect of sudden transitions in said first waveform; and means for comparing the first and second waveforms to produce a signal indicative of the characteristics of the material under investigation.
Claim 2
Dependent Claim
86 words
In a system for inspecting material having means for collecting electromagnetic radiation influenced by the presence of said material and means for producing a first electrical waveform dependent on said collected radiation the improvement comprising: means for deriving a second electrical waveform having the same general shape as that of the first waveform but modified in respect of sudden transitions in said first waveform; and means for comparing the first and second waveforms to produce a signal indicative of the characteristics of the material under investigation.
Claim 3
Dependent Claim
13 words
A system according to claim 1, wherein said deriving means includes a filter.
Claim 4
Dependent Claim
13 words
A system according to claim 2, wherein the filter is a low-pass filter.
Claim 5
Dependent Claim
131 words
In a system for inspecting material having means for collecting electromagnetic radiation influenced by the presence of said material and means for producing a first electrical waveform dependent on said collected radiation; said first waveform being in the form of a series of square wave pedestals each having a top containing information indicative of the characteristics of the material under investigation; the improvement comprising: means for deriving a second electrical waveform composed of a series of square wave pedestals each having the same general shape as an associated pedestal of the first waveform but being modified in respect of sudden transitions in the top of said associated pedestal constituting said information; and means for comparing the first and second waveforms to ascertain the presence of said information in the first waveform.
Claim 6
Dependent Claim
131 words
In a system for inspecting material having means for collecting electromagnetic radiation influenced by the presence of said material and means for producing a first electrical waveform dependent on said collected radiation; said first waveform being in the form of a series of square wave pedestals each having a top containing information indicative of the characteristics of the material under investigation; the improvement comprising: means for deriving a second electrical waveform composed of a series of square wave pedestals each having the same general shape as an associated pedestal of the first waveform but being modified in respect of sudden transitions in the top of said associated pedestal constituting said information; and means for comparing the first and second waveforms to ascertain the presence of said information in the first waveform.
Claim 7
Dependent Claim
13 words
A system according to claim 4, wherein said deriving means includes a filter.
Claim 8
Dependent Claim
34 words
A systeM according to claim 5, wherein said filter is a low-pass filter and there is further provided means for selectively controlling the cut-off frequency of said filter during the period of each pedestal.
Claim 9
Dependent Claim
47 words
A system according to claim 4, wherein the comparison means produces a signal whenever information indicative of flaws in the material is present in the first waveform and there is further provided means for providing a digital indication of the total duration of said comparison means signal.
Claim 10
Dependent Claim
43 words
A system according to claim 7, wherein said digital indication providing means is composed of a source of regularly recurrent timing pulses, a counter and means for controlling the flow of timing pulses to the counter in accordance with the comparison means signal.
Claim 11
Dependent Claim
79 words
A system according to claim 4, wherein the deriving means produces a second waveform which has a peak level which is substantially the same as the peak level of the associated pedestal and the comparison means produces an electrical pulse having a time duration proportional to the duration of time that a transition from the peak level of one of the pedestals containing said information differs from the corresponding part of the peak level of the associated comparison waveform.
Claim 12
Dependent Claim
50 words
A system according to claim 4, and further comprising means for automatically assessing the quality of each of the pedestals by examining each pedestal in respect of a number of specific features and means for inhibiting the system from operating should any of said features fall below a pre-determined standard.
Claim 13
Dependent Claim
60 words
A system according to claim 4, wherein the material is in the form of a sheet one surface of which is subjected to inspection and there is provided means for detecting the presence of the terminal ends of the sheet and moves sensitive to said detecting means for inhibiting the system from operating when radiation is collected adjacent said ends.
Claim 14
Dependent Claim
26 words
A system according to claim 4, wherein there is provided means for selectively removing polarized components of the radiation prior to collection by said collection means.
Claim 15
Dependent Claim
45 words
A system according to claim 4, wherein there is provided at least one attenuating means for attenuating at least one of the first and second waveforms to establish a pre-determine relationship between the peak levels of the associated pedestals of the first and second waveforms.
Claim 16
Dependent Claim
16 words
A system according to claim 13, wherein said at least one attenuating means is manually adjustable.
Claim 17
Dependent Claim
102 words
In a system for inspecting material having means for collecting electromagnetic radiation influenced by the presence of said material and means for producing a first electrical waveform from the collected radiation; the improvement comprising: means for deriving an analogue comparison waveform from said first waveform, the comparison waveform having the same general shape as the first waveform with a peak level in predetermined relationship to the peak level of the first waveform; and means for comparing the comparison waveform with the first waveform to ascertain the presence of information in the top of the first waveform indicative of flaws in the material.
Claim 18
Dependent Claim
102 words
In a system for inspecting material having means for collecting electromagnetic radiation influenced by the presence of said material and means for producing a first electrical waveform from the collected radiation; the improvement comprising: means for deriving an analogue comparison waveform from said first waveform, the comparison waveform having the same general shape as the first waveform with a peak level in predetermined relationship to the peak level of the first waveform; and means for comparing the comparison waveform with the first waveform to ascertain the presence of information in the top of the first waveform indicative of flaws in the material.
Claim 19
Dependent Claim
71 words
An electronic system for processing a first waveform produced by material inspection equipment to extract information therefrom; said system comprising means for receiving said first waveform and for producing a second waveform having the same general shape as that of the first waveform but modified in respect of sudden transitions in said first waveform and means for comparing said first and second waveforms to produce a signal indicative of said information.
Claim 20
Dependent Claim
71 words
An electronic system for processing a first waveform produced by material inspection equipment to extract information therefrom; said system comprising means for receiving said first waveform and for producing a second waveform having the same general shape as that of the first waveform but modified in respect of sudden transitions in said first waveform and means for comparing said first and second waveforms to produce a signal indicative of said information.
Claim 21
Dependent Claim
149 words
In an electronic system for processing a first waveform composed of a series of square-wave pedestals produced by material inspection equipment to extract information contained in the peak levels of the pedestals the improvement comprising: a low-pass filter with an input for receiving the first waveform and an output producing a comparison waveform from each of the Pedestals; means for altering the cut-off frequency of the filter from a higher value to a lower value just after the leading edge of each pedestal has occurred and from the lower value back to the higher value just before the lagging edge of each pedestal has occurred to thereby ensure that the leading and lagging edges of each pedestal are preserved in the associated comparison waveform; and means for comparing each pedestal with its associated comparison waveform to ascertain the presence of said information in the peak level of the pedestal.
Claim 22
Dependent Claim
149 words
In an electronic system for processing a first waveform composed of a series of square-wave pedestals produced by material inspection equipment to extract information contained in the peak levels of the pedestals the improvement comprising: a low-pass filter with an input for receiving the first waveform and an output producing a comparison waveform from each of the Pedestals; means for altering the cut-off frequency of the filter from a higher value to a lower value just after the leading edge of each pedestal has occurred and from the lower value back to the higher value just before the lagging edge of each pedestal has occurred to thereby ensure that the leading and lagging edges of each pedestal are preserved in the associated comparison waveform; and means for comparing each pedestal with its associated comparison waveform to ascertain the presence of said information in the peak level of the pedestal.
Claim 23
Independent Claim
80 words
A method of inspecting materials, said method comprising collecting electromagnetic radiation influenced by the presence of said material; producing a first electrical waveform from the collected radiation; deriving a second electrical waveform having the same general shape as that of the first waveform but modified in respect of sudden transitions in said first waveform; and comparing the first and second waveforms to detect the presence of information in the first waveform indicative of the characteristics of the material under investigation.
Claim 24
Independent Claim
80 words
A method of inspecting materials, said method comprising collecting electromagnetic radiation influenced by the presence of said material; producing a first electrical waveform from the collected radiation; deriving a second electrical waveform having the same general shape as that of the first waveform but modified in respect of sudden transitions in said first waveform; and comparing the first and second waveforms to detect the presence of information in the first waveform indicative of the characteristics of the material under investigation.
Claim 25
Dependent Claim
29 words
A method according to claim 18, wherein said second waveform is an analogue waveform with a peak level in pre-determined relationship to the peak level of the first waveform.
Claim 26
Independent Claim
102 words
A method of processing a first waveform composed of a series of square-wave pedestals produced by material inspection equipment to extract information contained in the peak levels of the pedestals; said method comprising producing an analogue comparison waveform from each of the pedestals, the comparison waveform having the same general shape as the associated pedestal with a peak level in pre-determined relationship to the peak level of the associated pedestals but modified in respect of sudden transitions in the top of the pedestal representing said information; and comparing the comparison waveform with its associated pedestal to detect the presence of said information.
Claim 27
Independent Claim
102 words
A method of processing a first waveform composed of a series of square-wave pedestals produced by material inspection equipment to extract information contained in the peak levels of the pedestals; said method comprising producing an analogue comparison waveform from each of the pedestals, the comparison waveform having the same general shape as the associated pedestal with a peak level in pre-determined relationship to the peak level of the associated pedestals but modified in respect of sudden transitions in the top of the pedestal representing said information; and comparing the comparison waveform with its associated pedestal to detect the presence of said information.
References Cited (Backward Citations)
US3280692A
Cited
US3612702A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-17 | 1977-06-18 | 1977-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-17 | 1981-06-18 | 1981-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-17 | 1985-06-18 | 1985-12-18 | $7700.00 | Window Closed / Lapsed |