Radiometric system
First Claim
1. A radiometric system for simultaneously measuring the temperature and the emissivity of a radiating body in accordance with theoretical data derived for an ideal linear detector, the system comprising:
- idealized ratio pyrometer means for generating two idealized brightness pyrometer signals in response to radiation received from the radiating body, each of the brightness pyrometer signals having respective components related to an associated constant factor, emissivity, and temperature of the radiating body, and producing an idealized ratio output signal independent of emissivity and indicative of the temperature of the radiating body; and
emissivity circuit means operatively connected to the ratio pyrometer means for comparing the ratio output signal with one of the brightness pyrometer signals, and producing an output signal independent of the temperature and indicative of the emissivity of the radiating body.
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Abstract
A radiometric system for simultaneously measuring the temperature and the emissivity of a radiating body in accordance with theoretically derived data, the system comprising a pair of idealized brightness pyrometers suitably coupled to one another to constitute an idealized ratio pyrometer which produces temperature measurements in conformity with the theoretically derived data, and including means for comparing output signals from the ratio pyrometer with corresponding output signals from one of the brightness pyrometers to produce emissivity measurements of the radiating body.
18 Citations
21 Claims
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1. A radiometric system for simultaneously measuring the temperature and the emissivity of a radiating body in accordance with theoretical data derived for an ideal linear detector, the system comprising:
- idealized ratio pyrometer means for generating two idealized brightness pyrometer signals in response to radiation received from the radiating body, each of the brightness pyrometer signals having respective components related to an associated constant factor, emissivity, and temperature of the radiating body, and producing an idealized ratio output signal independent of emissivity and indicative of the temperature of the radiating body; and
emissivity circuit means operatively connected to the ratio pyrometer means for comparing the ratio output signal with one of the brightness pyrometer signals, and producing an output signal independent of the temperature and indicative of the emissivity of the radiating body.
- idealized ratio pyrometer means for generating two idealized brightness pyrometer signals in response to radiation received from the radiating body, each of the brightness pyrometer signals having respective components related to an associated constant factor, emissivity, and temperature of the radiating body, and producing an idealized ratio output signal independent of emissivity and indicative of the temperature of the radiating body; and
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2. a radiometric system as set Forth in claim 1 wherein the ratio pyrometer means includes first and second brightness pyrometer means for receiving respective radiation intnesities emitted simultaneously from the radiating body and producing proportionate output signals in conformity with theoretical data derived for an ideal linear detector.
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3. A radiometric system as set forth in claim 2 wherein the emissivity circuit means includes signal comparing means operatively connected to the ratio pyrometer means for receiving corresponding output signals produced by the ratio pyrometer means and said brightness pyrometer means, respectively, and producing a ratio output signal having a temperature component substantially equal to one and an emissivity component proportionate to the emissivity of the radiating body.
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4. A radiometric system as set forth in claim 2 wherein the emissivity circuit means includes signal enhancing means operatively connected to the ratio pyrometer means for effectively eliminating the constant factor components of respective output signals produced by the ratio pyrometer means and said one of the brightness pyrometer means and producing an output signal substantially independent of the constant factor components.
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5. A radiometric system as set forth in claim 2 wherein the first and second brightness pyrometer means include respective first and second radiation selecting means for receiving radiation emitted from the radiating body and restricting passage thereof to radiation intensities associated with respective wavelengths of interest, the wavelengths being suitably close to one another in the spectrum to represent an emissivity ratio substantially equal to one.
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6. A radiometric system as set forth in claim 5 wherein the first and second brightness pyrometer means include respective first and second radiation detecting means operatively coupled to the first and second radiation selecting means, respectively, for receiving radiation intensities therefrom and producing corresponding exponentially variable output signals having respective components related to an associated constant factor, emissivity, and temperature of the radiating body.
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7. A radiometric system as set forth in claim 6 wherein the first and second brightness pyrometer means include respective first and second signal linearizing means operatively connected to the first and second radiation detecting means, respectively, for receiving the exponentially variable output signals therefrom and producing corresponding linearly variable signals having respective components related to an associated constant factor, emissivity and temperature of the radiating body.
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8. A radiometric system as set forth in claim 7 wherein the first and second brightness pyrometer means include respective first and second signal idealizing means operatively connected to the first and second signal linearizing means, respectively, for receiving the linearly variable output signals therefrom and producing corresponding idealized output signals in conformity with theoretical data derived for an ideal linear detector, each of the idealized output signals having respective components related to an associated constant factor, emissivity, and temperature of the radiating body, the emissivity components of corresponding idealized output signals produced by the first and second idealizing means being substantially equal to one another.
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9. A radiometric system as set forth in claim 8 wherein the ratio pyrometer means includes signal ratio means operatively connected to the first and second linearizing means, respectively, for receiving the idealized output signals therefrom and producing a corresponding idealized ratio output signal independent of emissivity and indicative of the temperature of the radiating body.
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10. A radiometric system as set forth in claim 9 and including a temperature indicating means operatively connected to the signal ratio means for receiving the idealized ration output signal therefrom and displaying a coRresponding temperature of the radiating body.
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11. A radiometric system as set forth in claim 9 wherein the emissivity circuit means includes signal conforming means operatively connected to one of the signal idealizing means for receiving the output signal therefrom as an input signal and producing a corresponding output signal having a temperature component substantially equal to the temperature component of the output signal produced by the signal ratio means.
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12. A radiometric system as set forth in claim 11 wherein the signal conforming means includes signal reducing means for decreasing the magnitude of the input signal received from the signal idealizing means and producing an output signal having corresponding constant factor, emissivity, and temperature components uniformly reduced in magnitude accordinly, the resulting temperature component being equal in magnitude to the temperature component of the output signal produced by the signal ratio means.
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13. A radiometric system as set forth in claim 11 wherein the emissivity circuit means includes signal comparing means operatively connected to the signal conforming means and to the signal ratio means for receiving corresponding output signals therefrom as respective input signals, the signal comparing means including ratio circuit means for effectively cancelling the subtantially equal temperature components of the respective input signals and producing a ratio output signal having respective components related to an associated constant factor and the emissivity of the radiating body.
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14. A radiometric system as set forth in claim 13 wherein the ratio circuit means includes signal subtracting means for comparing the respective idealized linearly variable input signals and extracting the difference as an output signal equivalent to obtaining the ratio of corresponding exponentially variable signals.
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15. A radiometric system as set forth in claim 13 wherein the emissivity circuit means includes signal enhancing means operatively connected to the signal comparing means for removing the constant factor component of the output signal received therefrom and amplifying the remaining emissivity component.
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16. A radiometric system as set forth in claim 15 wherein the signal enhancing means includes negative signal generating means for removing the constant factor component by combining it with an oppositely polarized signal of equal magnitude.
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17. A radiometric system as set forth in claim 15 wherein the signal enhancing means includes signal restoring means for amplifying the remaining emissivity component to equal the emissivity component of the corresponding output signal produced by said one of the brightness pyrometer means.
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18. A radiometric system as set forth in claim 17 wherein the emissivity circuit means includes signal delinearizing means operatively connected to the signal enhancing means for receiving the linearly variable output signal therefrom and producing a corresponding exponentially variable output signal in conformity with the exponentially variable signal produced by the associated radiation detecting means.
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19. A radiometric system as set forth in claim 18 wherein the signal delinearizing means includes antilog circuit means for producing an exponentially variable signal equal to the emissivity component of the corresponding output signal produced by the associated radiation detecting means in proportion to radiation intensity received from the radiating surface.
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20. A radiometric system as set forth in claim 18 and including emissivity indicating means operatively connected to the signal delinearizing means for receiving the exponentially variable output signal therefrom and displaying the corresponding value of emissivity.
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21. A method of idealizing the output of an actual radiation detector to conform with the output of an ideal linear detector, the method comprising the steps of:
- calculating the output of an ideal lindear detector receiving a particular Wavelength of black body radiation at a series of selected temperatures;
plotting the calculated values to obtain an ideal detector output versus black body temperature curve;
finding a Tn curve equation having a constant factor component and an exponentially variable temperture factor component which conforms closely to the plotted curve of calculated values;
taking the log 10 of the equation to obtain a calculated value equation of a linear curve having a slope equal to n;
measuring the output of an actual detector receiving the particular wavelength of black body radiation at a series of selected temperatures;
plotting the measure values to obtain an actual detector output versus black body temperature curve;
finding a Tnm curve equation having a constant factor component and an exponentially variable temperature factor component which conforms closely to the plotted curve of measured values;
taking the log 10 of the equation to obtain a resulting measured value equation of a linear curve having a slope equal to nm; and
dividing the resulting measured value equation by the factor m to obtain a measured value equation of a linear curve having a slope equal to n.
- calculating the output of an ideal lindear detector receiving a particular Wavelength of black body radiation at a series of selected temperatures;
Specification