Predictive temperature measurement system
First Claim
Patent Images
1. A thermometer for measuring the temperature of an object, comprising:
- a sensor which, when positioned to sense the temperature of the object, provides a time varying temperature signal in response to the temperature of the object;
a processor connected so as to sample the temperature signal a predetermined number of times, to determine the average value, the first derivative, and the second derivative of the temperature signal based upon the predetermined number of samples acquired, and to combine the average value, first derivative, and second derivative to calculate an estimate of the temperature of the object and provide an estimated final temperature signal, wherein the processor comprises a finite impulse response (FIR) filter configured to calculate the temperature estimate; and
a display connected with the processor to receive and display the estimated final temperature signal.
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Abstract
A method and device for rapidly predicting the temperature of an object through a sensor reading of the object'"'"'s temperature by using a processor comprising finite impulse response (FIR) filters to determine the average value, the first derivative, and the second derivative of the sensed temperature based upon a predetermined number of temperature samples, apply a respective weighting factor to each of the average value, the first derivative, and the second derivative respectively, and calculate a temperature estimate by combining the weighted average value, the first derivative, and second derivative together with an offset factor.
97 Citations
25 Claims
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1. A thermometer for measuring the temperature of an object, comprising:
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a sensor which, when positioned to sense the temperature of the object, provides a time varying temperature signal in response to the temperature of the object;
a processor connected so as to sample the temperature signal a predetermined number of times, to determine the average value, the first derivative, and the second derivative of the temperature signal based upon the predetermined number of samples acquired, and to combine the average value, first derivative, and second derivative to calculate an estimate of the temperature of the object and provide an estimated final temperature signal, wherein the processor comprises a finite impulse response (FIR) filter configured to calculate the temperature estimate; and
a display connected with the processor to receive and display the estimated final temperature signal. - View Dependent Claims (2)
a first finite impulse response filter configured to calculate the average value based on the last predetermined number of samples acquired by the processor;
a second finite impulse response filter configured to calculate the first derivative based on the last predetermined number of samples acquired by the processor; and
a third finite impulse response filter configured to calculate the second derivative based on the last predetermined number of samples acquired by the processor.
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3. A thermometer for measuring the temperature of an object, comprising:
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a sensor which, when positioned to sense the temperature of the object, provides a time varying temperature signal in response to the temperature of the object;
a processor connected so as to sample the temperature signal a predetermined number of times, to determine the average value, the first derivative, and the second derivative of the temperature signal based upon the predetermined number of samples acquired, and to combine the average value, first derivative, and second derivative to calculate an estimate of the temperature of the object and provide an estimated final temperature signal;
wherein the processor further applies a separate weighting factor to each of the average value, the first derivative, and the second derivative prior to combining the average value, the first derivative, and the second derivative to calculate the temperature estimate;
wherein the processor further adds an ambient temperature offset coefficient to the sum of the weighted average value, first derivative, and second derivative to calculate the temperature estimate; and
a display connected with the processor to receive and display the estimated final temperature signal. - View Dependent Claims (4)
the sensor further provides an initial signal corresponding to the ambient temperature; and
the processor further determines the square of the ambient temperature, applies a separate weighting factor to each of the ambient temperature and the square of the ambient temperature, and combines the weighted value of the ambient temperature with the weighted square of the value of the ambient temperature to calculate the ambient temperature offset coefficient.
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5. A method for measuring the temperature of an object, comprising the steps of:
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sensing the temperature of the object;
providing a time varying temperature signal responsive to sensing the temperature of the object;
sampling the temperature signal a predetermined number of times;
determining the average value of the temperature signal based upon the predetermined number of samples acquired;
determining the first derivative of the temperature signal based upon the predetermined number of samples acquired;
determining the second derivative of the temperature signal based upon the predetermined number of samples acquired; and
calculating an estimate of the temperature of the object by combining the average value, the first derivative, and the second derivative. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
applying a first weighting factor to the average value;
applying a second weighting factor to the first derivative; and
applying a third weighting factor to the second derivative.
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7. The method of claim 5 wherein the step of sampling the temperature signal a predetermined number of times comprises sampling the temperature signal around twenty-one times over a time frame of approximately two seconds.
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8. The method of claim 5 comprising the further steps of:
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repeatedly sampling the temperature signal; and
repeatedly recalculating the temperature estimate based on the last predetermined number of samples obtained as each new sample is acquired.
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9. The method of claim 5 comprising the further step of displaying the temperature estimate on a display.
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10. The method of claim 9 wherein the step of displaying the temperature estimate is performed after the temperature of the object has been sensed for a predetermined length of time.
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11. The method of claim 9 wherein the step of displaying the temperature estimate is performed only when the last value of the first derivative calculated by the processor lies in a predetermined range of values.
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12. The method of claim 9 wherein the step of displaying the temperature estimate is performed only when the last value of the second derivative calculated by the processor lies in a predetermined range of values.
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13. The method of claim 9 wherein the step of displaying the temperature estimate is performed only when the maximum difference between selected temperature estimates calculated by the processor is less than a predetermined value.
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14. The method of claim 9 wherein the step of calculating an estimate of the temperature of the object comprises the further step of:
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averaging a predetermined number of the temperature estimates calculated by the processor to calculate a final temperature estimate; and
whereinthe step of displaying the temperature estimate is comprised of displaying the final temperature estimate.
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15. The method of claim 5 further comprising the step of providing the sampled temperature signals to at least one FIR filter and thereby performing the steps of determining the average value of the temperature signal, determining the first derivative of the temperature signal, and determining the second derivative of the temperature signal by the FIR filter.
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16. The method of claim 15 wherein the step of providing the sampled temperature signal to at least one FIR filter comprises the steps of:
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providing the sampled temperature signals to a first FIR for calculating the average value based on a predetermined number of sample values acquired;
providing the sampled temperature signals to a second finite impulse response filter for calculating the first derivative based on a predetermined number of sample values acquired; and
providing the sampled temperature signals to a third finite impulse response filter for calculating the second derivative based on a predetermined number of sample values acquired.
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17. The method of claim 15 wherein:
the step of providing an FIR filter comprises applying weights to the average value, the first derivative, and the second derivative based on a predetermined number of sample values acquired.
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18. The method of claim 17 further comprising the step of combining the weighted average value, the weighted first derivative, and the weighted second derivative to determine the estimated temperature of the object.
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19. The method of claim 6 comprising the further steps of:
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sensing the ambient temperature;
determining the square of the value of the ambient temperature;
applying a fourth weighting factor to the ambient temperature;
applying a fifth weighting factor to the square of the ambient temperature; and
whereinthe step of calculating the estimate of the temperature of the object comprises combining the weighted average value, the weighted first derivative, and the weighted second derivative with the weighted ambient temperature and the weighted square of the ambient temperature.
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20. A thermometer for measuring the temperature of a biological subject, comprising:
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a sensor which, when positioned to sense the temperature of the subject, provides a time varying temperature signal in response to the temperature of the subject;
a processor comprising a finite impulse response filter connected so as to sample the temperature signal a predetermined number of times, to determine the average value, the first derivative, and the second derivative of the temperature signal based upon the predetermined number of samples acquired, the processor also configured to combine the average value, first derivative, and second derivative to calculate an estimate of the temperature of the subject and provide an estimated final temperature signal;
wherein the processor comprises;
a first finite impulse response filter configured to calculate the average value based on the last predetermined number of samples acquired by the processor;
a second finite impulse response filter configured to calculate the first derivative based on the last predetermined number of samples acquired by the processor; and
a third finite impulse response filter configured to calculate the second derivative based on the last predetermined number of samples acquired by the processor; and
a display connected with the processor to receive and display the estimated final temperature signal.
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21. A thermometer for measuring the temperature of a biological subject, comprising:
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a sensor which, when positioned to sense the temperature of the subject, provides a time varying temperature signal in response to the temperature of the subject;
a processor comprising a finite impulse response filter connected so as to sample the temperature signal a predetermined number of times, to determine the average value, the first derivative, and the second derivative of the temperature signal based upon the predetermined number of samples acquired, the processor also configured to combine the average value, first derivative, and second derivative to calculate an estimate of the temperature of the subject and provide an estimated final temperature signal;
wherein the processor further adds an ambient temperature offset coefficient to the sum of the weighted average value, first derivative, and second derivative to calculate the temperature estimate; and
a display connected with the processor to receive and display the estimated final temperature signal. - View Dependent Claims (22)
the sensor further provides an initial signal corresponding to ambient temperature; and
the processor further determines the square of the ambient temperature, applies a separate weighting factor to each of the ambient temperature and the square of the ambient temperature, and combines the weighted value of the ambient temperature with the weighted square of the value of the ambient temperature to calculate the ambient temperature offset coefficient.
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23. A thermometer for measuring the temperature of a biological subject, comprising:
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a sensor which, when positioned to sense the temperature of the subject, provides a time varying temperature signal in response to the temperature of the subject;
a processor comprising a finite impulse response filter connected so as to sample the temperature signal a plurality of times to calculate an estimate of the temperature of the subject and provide an estimated final temperature signal; and
a display connected with the processor to receive and display the estimated final temperature signal. - View Dependent Claims (24, 25)
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Specification