Patent US5094544A successfully refreshed from Google Patents.
US5094544A
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US
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Scanning infrared thermometer with DC offset and emissivity correction
Assignee: Fluke Corp
•
Filing: 1990-10-19
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Granted: 1992-03-10
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Expires: 2010-10-19
Abstract
Abstract A scanning infrared sensor (10) in which the scanner (21), detector (32) and temperature converter (35) are all contained in proximity with one another in a single housing assembly (18) enables correction of both emissivity based on emissivity settings (41) for each of a plurality of spot targets (16') along a scan line (16) and correction for DC offset errors based on reference temperature measurement (45) of hot and cold references (34, 36). Correction is performed before digital conversion by an A/D converter (56) by a nulling circuit (46), a programmable gain circuit (50) and a bias circuit (62) to produce corrected digital temperature signals on a plurality of output ports (26) respectively associated to a plurality of spot targets (16') along a scan line (16) on a target (12) which are individually connectable with a multiple temperature display (27), a temperature recorder (28) and a process control (30).
Inventors
- 👤 Steven A. Ignatowicz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:07
CPC Classifications
G; G01; G01J; G01J5/00; G01J5/52; G01J5/02; G01J5/026; G01J5/04; G01J5/48; G01J5/53; G01J5/80; G01J2005/0092
Claims Analysis
Total Claims: 81
Claim 1
Independent Claim
144 words
In a scanning infrared thermometer having an optical system for collecting light from a target and means including a photoelectrical detector for converting the collected light to an analog radiation temperature signal having a magnitude related to temperature, the improvement being a correction circuit, comprising: means for altering the analog temperature signal to produce a corrected analog temperature signal in which errors due to emissivity are reduced including a reference, and means for correcting for emissivity; means responsive to the reference for automatically correcting for DC offset fluctuations prior to correction by said emissivity correcting means; means including an analog to digital converter for converting the corrected analog temperature signal to generate a corresponding corrected digital temperature signal representative of the magnitude of the corrected analog temperature signal; and means responsive to the corrected digital temperature signal for displaying the temperature of the target.
Claim 2
Dependent Claim
144 words
In a scanning infrared thermometer having an optical system for collecting light from a target and means including a photoelectrical detector for converting the collected light to an analog radiation temperature signal having a magnitude related to temperature, the improvement being a correction circuit, comprising: means for altering the analog temperature signal to produce a corrected analog temperature signal in which errors due to emissivity are reduced including a reference, and means for correcting for emissivity; means responsive to the reference for automatically correcting for DC offset fluctuations prior to correction by said emissivity correcting means; means including an analog to digital converter for converting the corrected analog temperature signal to generate a corresponding corrected digital temperature signal representative of the magnitude of the corrected analog temperature signal; and means responsive to the corrected digital temperature signal for displaying the temperature of the target.
Claim 3
Dependent Claim
53 words
The scanning infrared thermometer of claim 1 in which said emissivity correcting means includes means for preselecting an emissivity setting according to the emissivity characteristics of a target, and means responsive to the preselected emissivity setting for altering the analog temperature signal to produce a corrected temperature signal corrected for different emissivity settings.
Claim 4
Dependent Claim
46 words
The scanning infrared thermometer of claim 2 including means for concurrently determining the temperature of a plurality of spots on a target, and in which said emissivity setting preselecting means includes means for individually preselecting an emissivity setting for each of the spots of the target.
Claim 5
Dependent Claim
25 words
The scanning infrared thermometer of claim 1 in which emissivity correcting means includes means for automatically, proportionately altering the magnitude of the analog temperature signal.
Claim 6
Dependent Claim
33 words
The scanning infrared thermometer of claim 4 in which said automatically, proportionably altering means includes a programmable gain circuit, and means for automatically controlling said programmable gain circuit to correct for circuit instability.
Claim 7
Dependent Claim
33 words
The scanning infrared thermometer of claim 4 in which said automatically, proportionately altering means includes a programmable gain circuit, and means for automatically controlling said programmable gain circuit to correct for component variations.
Claim 8
Dependent Claim
46 words
The scanning infrared thermometer of claim 4 in which said proportional altering means includes a programmable gain circuit connected between the detector and the analog to digital converter, and a controller responsive to changes in emissivity for selectively changing the gain of the programmable gain circuit.
Claim 9
Dependent Claim
24 words
The scanning infrared thermometer of claim 7 in which said DC fluctuations correcting means is connected between the detector and the proportionally altering means.
Claim 10
Dependent Claim
47 words
The scanning infrared thermometer of claim 1 in which said DC offset fluctuations correcting means includes a nulling circuit connected between the detector and the analog to digital converter, and a controller responsive to changes in emissivity for selectively changing the DC offset of the nulling circuit.
Claim 11
Dependent Claim
31 words
The scanning infrared thermometer of claim 1 in which said digital temperature signal generating means includes a memory encoded with linearizing data for producing a linearized and corrected digital temperature signal.
Claim 12
Dependent Claim
19 words
The scanning infrared thermometer of claim 10 in which said linearizing data is in a direct look-up table format.
Claim 13
Dependent Claim
15 words
The scanning infrared thermometer of claim 10 in which said memory is a static memory.
Claim 14
Dependent Claim
31 words
The scanning infrared thermometer of claim 10 in which said memory is encoded with data for selectively producing linearizing data for display of temperature selectively in Celsius degrees and Fahrenheit degrees.
Claim 15
Dependent Claim
36 words
The scanning infrared thermometer of claim 1 including a bias circuit for selectively biasing the analog to digital converter to selectively alter the corrected digital temperature signal in accordance with a relatively cold reference temperature signal.
Claim 16
Dependent Claim
45 words
The scanning infrared thermometer of claim 1 in which said corrected temperature signal producing means includes a controller responsive to at least one reference temperature signal circuit for changing at least one of the analog temperature signals in accordance with control signals from said controller.
Claim 17
Dependent Claim
20 words
The scanning infrared thermometer of claim 15 in which said controller is responsive to a relatively cold reference temperature signal.
Claim 18
Dependent Claim
20 words
The scanning infrared thermometer of claim 16 in which said controller is responsive to a relatively hot reference temperature signal.
Claim 19
Dependent Claim
20 words
The scanning infrared thermometer of claim 15 in which said controller is responsive to a relatively hot reference temperature signal.
Claim 20
Dependent Claim
48 words
The scanning infrared thermometer of claim 1 including means for causing said optical system to scan for individual measurement of a plurality of discrete spots on a target, and said emissivity correcting includes means for correcting for emissivity at least once per complete scan of the scanning means.
Claim 21
Dependent Claim
37 words
The scanning infrared thermometer of claim 19 in which the emissivity fluctuation correcting means includes means for correcting for fluctuations in emissivity individually for each spot per scan in accordance with preselected emissivity settings for such spot.
Claim 22
Dependent Claim
67 words
The scanning infrared thermometer of claim 1 including a housing assembly for protectively enclosing in proximity the corrected analog temperature signal producing means and the corrected digital temperature signal generating means, and an interface including a plurality of output ports connected with said corrected digital signal generating means and mounted to the housing for respectively receiving therefrom corrected digital temperature signals for a plurality of different spots.
Claim 23
Dependent Claim
24 words
The scanning infrared thermometer of claim 21 including means mounted within the housing assembly for linearizing the converted digital temperature signals for each spot.
Claim 24
Dependent Claim
19 words
The scanning infrared thermometer of claim 21 in which said temperature displaying means is mounted to the housing assembly.
Claim 25
Dependent Claim
38 words
The scanning infrared thermometer of claim 21 in which said housing assembly is formed of a single housing within which all of the corrected analog temperature providing means and the corrected digital temperature signal generating means are enclosed.
Claim 26
Dependent Claim
73 words
The scanning infrared thermometer of claim 24 in which said analog temperature signal producing means includes means for concurrently providing corrected analog temperature signals for each of a plurality of samples for each of a plurality of spots on the target, and said corrected digital temperature signal generating means includes means responsive to each of the corrected analog temperature signals for providing an average corrected digital temperature signal for each of said spots.
Claim 27
Dependent Claim
73 words
The scanning infrared thermometer of claim 1 in which said analog temperature signal producing means includes means for concurrently providing corrected analog temperature signals for each of a plurality of samples for each of a plurality of spots on the target, and said corrected digital temperature signal generating means includes means responsive to each of the corrected analog temperature signals for providing an average corrected digital temperature signal for each of said spots.
Claim 28
Dependent Claim
117 words
In a scanning infrared thermometer having a scanning optical system for collecting light from a target and means including a photoelectrical element for converting the collected light to an analog temperature signal with a magnitude related to temperature, the improvement being a correcting circuit, comprising: means for automatically altering the analog temperature signal to correct for DC offset errors from the detector to produce a first order corrected analog temperature signal; means including an analog to digital converter for converting the corrected analog temperature signal to a corresponding corrected digital temperature signal representative of magnitude of the corrected analog temperature signal; and means responsive to the corrected digital temperature signal for displaying the temperature of the target.
Claim 29
Dependent Claim
117 words
In a scanning infrared thermometer having a scanning optical system for collecting light from a target and means including a photoelectrical element for converting the collected light to an analog temperature signal with a magnitude related to temperature, the improvement being a correcting circuit, comprising: means for automatically altering the analog temperature signal to correct for DC offset errors from the detector to produce a first order corrected analog temperature signal; means including an analog to digital converter for converting the corrected analog temperature signal to a corresponding corrected digital temperature signal representative of magnitude of the corrected analog temperature signal; and means responsive to the corrected digital temperature signal for displaying the temperature of the target.
Claim 30
Dependent Claim
25 words
The scanning infrared thermometer of claim 27 in which said analog temperature signal altering means alters the analog signal in accordance with a reference signal.
Claim 31
Dependent Claim
37 words
The scanning infrared thermometer of claim 28 in which said altering means includes a nulling circuit, and means for controlling the nulling circuit to produce a null output when the optical system is sensing a reference target.
Claim 32
Dependent Claim
27 words
The scanning infrared thermometer of claim 29 in which said altering means includes means for introducing an offset to the input of the analog to digital converter.
Claim 33
Dependent Claim
27 words
The scanning infrared thermometer of claim 27 in which said altering means includes means for introducing an offset to the input of the analog to digital converter.
Claim 34
Dependent Claim
23 words
The scanning infrared thermometer of claim 27 including means for proportionately altering the magnitude corrected analog signal to further correct it for emissivity.
Claim 35
Dependent Claim
30 words
The scanning infrared thermometer of claim 27 in which said analog temperature altering means includes means for altering the DC offset in accordance with a relatively hot temperature reference signal.
Claim 36
Dependent Claim
31 words
The scanning infrared thermometer of claim 27 in which said digital temperature signal generating means includes a memory encoded with linearizing data for producing a linearized and corrected digital temperature signal.
Claim 37
Dependent Claim
19 words
The scanning infrared thermometer of claim 34 in which said linearizing data is in a direct look-up table format.
Claim 38
Dependent Claim
15 words
The scanning infrared thermometer of claim 34 in which said memory is a static memory.
Claim 39
Dependent Claim
31 words
The scanning infrared thermometer of claim 34 in which said memory is encoded with data for selectively producing linearizing data for display of temperature selectively in Celsius degrees and Fahrenheit degrees.
Claim 40
Dependent Claim
45 words
The scanning infrared thermometer of claim 27 in which said corrected temperature signal producing means includes a controller responsive to at least one reference temperature signal circuit for changing at least one of the analog temperature signals in accordance with control signals from said controller.
Claim 41
Dependent Claim
20 words
The scanning infrared thermometer of claim 38 in which said controller is responsive to a relatively cold reference temperature signal.
Claim 42
Dependent Claim
20 words
The scanning infrared thermometer of claim 39 in which said controller is responsive to a relatively hot reference temperature signal.
Claim 43
Dependent Claim
20 words
The scanning infrared thermometer of claim 38 in which said controller is responsive to a relatively hot reference temperature signal.
Claim 44
Dependent Claim
55 words
The scanning infrared thermometer of claim 27 including means for causing said optical system to scan for simultaneous measurement of a plurality of discrete spots on a target, and said corrected analog temperature signal producing means includes means for correcting for fluctuations in DC offset at least once per complete scan of the scanning means.
Claim 45
Dependent Claim
67 words
The scanning infrared thermometer of claim 27 including a housing assembly for protectively enclosing in proximity the corrected analog temperature signal providing means and the corrected temperature digital temperatures signal generating means, and an interface having a plurality of output ports connected with said corrected digital signal generating means and mounted to the housing for respectively receiving therefrom corrected digital temperature signals for the plurality of spots.
Claim 46
Dependent Claim
23 words
The scanning infrared thermometer of claim 43 including means for linearizing the converted digital temperature signals for each spot mounted within the housing.
Claim 47
Dependent Claim
18 words
The scanning infrared thermometer of claim 44 in which said temperature displaying means is mounted to the housing.
Claim 48
Dependent Claim
185 words
In a scanning infrared thermometer having a scanning optical system for collecting light from a target and means including a photoptical detector for converting the collected light to an analog temperature signal with a magnitude related to the temperature of the target, the improvement, comprising: a correcting circuit responsive to the analog temperature signal circuitry for producing a corrected analog temperature signal corrected for errors due to at least one of (a) variations in DC offset of the light converting means and (b) errors due to target emissivity, at least once per complete scan of the scanning optical system; a linearizing circuit responsive to the corrected analog temperature signal for producing a linearized corrected digital temperature signal; a controller responsive to the linearized, corrected temperature signal for controlling the correcting circuit; a housing assembly for protectively enclosing together in proximity the correcting circuit linearizing circuit and the controller; and an output interface including an output terminal mounted to and accessibly from the outside of the housing, and means for producing a representation of the linearized, corrected temperature signal at said output terminal in digital form.
Claim 49
Dependent Claim
185 words
In a scanning infrared thermometer having a scanning optical system for collecting light from a target and means including a photoptical detector for converting the collected light to an analog temperature signal with a magnitude related to the temperature of the target, the improvement, comprising: a correcting circuit responsive to the analog temperature signal circuitry for producing a corrected analog temperature signal corrected for errors due to at least one of (a) variations in DC offset of the light converting means and (b) errors due to target emissivity, at least once per complete scan of the scanning optical system; a linearizing circuit responsive to the corrected analog temperature signal for producing a linearized corrected digital temperature signal; a controller responsive to the linearized, corrected temperature signal for controlling the correcting circuit; a housing assembly for protectively enclosing together in proximity the correcting circuit linearizing circuit and the controller; and an output interface including an output terminal mounted to and accessibly from the outside of the housing, and means for producing a representation of the linearized, corrected temperature signal at said output terminal in digital form.
Claim 50
Dependent Claim
21 words
The scanning infrared thermometer of claim 46 in which said correcting circuit corrects for both emissivity errors and DC offset errors.
Claim 51
Dependent Claim
29 words
The scanning infrared thermometer of claim 46 in which said correcting circuitry includes a nulling circuit responsive to a relatively cold reference signal to correct for zero offset errors.
Claim 52
Dependent Claim
43 words
The scanning infrared thermometer of claim 46 in which said correcting circuitry includes a programmable gain circuit responsive to different emissivity settings for different locations on the target to proportionally alter the magnitude of the analog temperature signal for each said different location.
Claim 53
Dependent Claim
52 words
The scanning infrared thermometer of claim 46 including means for producing a corrected, linearized digital temperature signals for a plurality of different spots on the target, and in which said output interface has a plurality of input-output parts for receiving the corrected, linearized digital temperature signals for said plurality of spots, respectively.
Claim 54
Dependent Claim
32 words
The scanning infrared thermometer of claim 46 in which said controller includes means for selecting different emissivity settings for different ones of said spots on the target where temperature is being measured.
Claim 55
Dependent Claim
159 words
In a scanning infrared thermometer having a scanning optical system for collecting light from a target and a detector circuit including a photoelectrical device for converting the collected light to an analog temperature signal having a magnitude related to temperature, the improvement being a correcting circuit, comprising: means for altering the analog temperature signal to correct for DC offset errors from the detector circuit to produce a corrected analog temperature signal; means for altering the magnitude of the analog temperature signal to correct for magnitude errors caused by at least two of emissivity effects, circuit stability and component variations; means including an analog to digital converter for converting the corrected analog temperature signal to a corresponding corrected digital temperature signal representative of the magnitude of the corrected analog temperature signal; and means responsive to the corrected digital temperature signal for outputting the signal in digital format to at least one of a display, a recorder and a process controller.
Claim 56
Dependent Claim
159 words
In a scanning infrared thermometer having a scanning optical system for collecting light from a target and a detector circuit including a photoelectrical device for converting the collected light to an analog temperature signal having a magnitude related to temperature, the improvement being a correcting circuit, comprising: means for altering the analog temperature signal to correct for DC offset errors from the detector circuit to produce a corrected analog temperature signal; means for altering the magnitude of the analog temperature signal to correct for magnitude errors caused by at least two of emissivity effects, circuit stability and component variations; means including an analog to digital converter for converting the corrected analog temperature signal to a corresponding corrected digital temperature signal representative of the magnitude of the corrected analog temperature signal; and means responsive to the corrected digital temperature signal for outputting the signal in digital format to at least one of a display, a recorder and a process controller.
Claim 57
Dependent Claim
23 words
The scanning infrared thermometer of claim 52 in which said offset correcting means alters the analog signal in accordance with the reference signal.
Claim 58
Dependent Claim
81 words
The scanning infrared thermometer of claim 52 in which said offset correcting means includes a nulling circuit, and means for controlling the nulling circuit to produce a null output prior to an input to the analog to digital converter when the optical system is sensing a relatively cold reference target, and means to introduce an offset signal at an input of the analog to digital converter which is generated in response to an independent temperature signal from the cold reference target.
Claim 59
Dependent Claim
31 words
The scanning infrared thermometer of claim 54 in which the analog termination signal magnitude adjusting means includes a programmable gain amplifier responsive to the controlling means responsive to an emissivity reference.
Claim 60
Dependent Claim
22 words
The scanning infrared thermometer of claim 55 in which the controlling means is also responsive to a relatively hot temperature reference target.
Claim 61
Dependent Claim
30 words
The scanning infrared thermometer of claim 55 in which said digital temperature generating means includes a memory encoded with linearizing data for producing a linearized and corrected digital temperature signal.
Claim 62
Dependent Claim
19 words
The scanning infrared thermometer of claim 57 in which said linearizing data is in a direct look-up table format.
Claim 63
Dependent Claim
28 words
The scanning infrared thermometer of claim 58 in which said memory is encoded to produce temperature readings selectively in standard temperature scales of degrees Celsius and degrees Fahrenheit.
Claim 64
Dependent Claim
24 words
The scanning infrared thermometer of claim 59 in which said memory includes address lines which are connected directly to digital converter data output lines.
Claim 65
Dependent Claim
29 words
The scanning infrared thermometer of claim 60 in which the controlling means is also responsive to a relatively hot temperature reference target when in view of the optical system.
Claim 66
Dependent Claim
25 words
The scanning infrared thermometer of claim 61 in which the controlling means is also responsive to an independent temperature signal from the hot reference target.
Claim 67
Dependent Claim
29 words
The scanning infrared thermometer of claim 60 where the controlling means integrates the cold reference readings over successive scan cycles to reduce system noise while controlling the nulling circuit.
Claim 68
Dependent Claim
27 words
The scanning infrared thermometer of claim 63 in which the controller and programmable gain amplifier are responsive to a plurality of emissivity settings along the scan line.
Claim 69
Dependent Claim
21 words
The scanning infrared thermometer of claim 64 in which the controlling means is also responsive to a relatively hot temperature reference.
Claim 70
Dependent Claim
31 words
The scanning infrared thermometer of claim 65 where the controlling means integrates the hot reference readings over successive scan cycles to reduce a system noise while controlling the programmable gain circuit.
Claim 71
Dependent Claim
25 words
The scanning infrared thermometer of claim 65 in which the controlling means is also responsive to an independent temperature signal from the hot reference target.
Claim 72
Dependent Claim
42 words
The scanning infrared thermometer of claim 67 the improvement being means to select discrete measurement spots from a thermal image including a controller to select samples during successive scans into at least one composite measurement, and means to output the composite measurements.
Claim 73
Dependent Claim
25 words
The scanning infrared thermometer of claim 68 in which the optical system, correcting means, and output means are contained in a single protective housing assembly.
Claim 74
Dependent Claim
17 words
The scanning thermometer of claim 69 including means to output the composite measurement as an analog signal.
Claim 75
Dependent Claim
26 words
The scanning thermometer of claim 70 including means to output a discrete binary signal respectively representing the composite measurement being above and below a reference setpoint.
Claim 76
Dependent Claim
21 words
The scanning infrared thermometer of claim 65 in which the controlling means is responsive to an independent hot temperature reference signal.
Claim 77
Dependent Claim
43 words
The scanning infrared thermometer of claim 64 including means to pick out discrete measurement spots from a thermal image including computing means to select samples along successive scan lines to determine one or more composite measurements, and means to output the composite measurements.
Claim 78
Dependent Claim
25 words
The scanning infrared thermometer of claim 73 in which the optical system, correcting means, and output means are contained in a single protective housing assembly.
Claim 79
Dependent Claim
17 words
The scanning thermometer of claim 73 including means to output the composite measurements as an analog signal.
Claim 80
Dependent Claim
27 words
The scanning infrared thermometer of claim 75 including means to output a discrete binary signal respectively representing the composite measurement being above and below a reference setpoint.
Claim 81
Dependent Claim
27 words
The scanning infrared thermometer of claim 54 in which the controller and programmable gain amplifier are responsive to a plurality of emissivity settings along the scan line.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1995-03-10 | 1995-09-09 | 1996-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-10 | 1999-09-09 | 2000-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-10 | 2003-09-09 | 2004-03-10 | $7700.00 | Window Closed / Lapsed |