Infrared thermometer
View Patent ↗An infrared ear thermometer includes a detector head housing, a heat sink, a recess formed in the heat sink, a thermopile sensor mounted within the recess, a thermistor, and temperature determination circuitry. The recess defines an aperture that limits the field of view of the thermopile sensor. The thermal capacities and conductivities of the heat sink and the thermopile sensor are selected so that the output signal of the thermopile sensor stabilizes during a temperature measurement. A method of determining temperature using the ear thermometer takes successive measurements, stores the measurements in a moving time window, averages the measurements in the moving window, determines whether the average has stabilized, and outputs an average temperature. A method of calculating a subject's temperature determines the temperature of a cold junction of the thermopile, looks up a bias and slope of the thermopile based upon the temperature of the cold junction, measures the output of the thermopile, and calculates the subject's temperature based upon a linear relationship between the output and the subject's temperature. The linear relationship is defined by the bias and the slope.
1. A method of detecting human body temperature, the method comprising:
placing a temperature detector against a forehead to take plural temperature measurements, the temperature detector comprising a radiation sensor which views a target surface area of the forehead, the temperature detector further comprising an extension for placement against the forehead, wherein the extension forms an air pocket isolating a portion of the forehead from air flow outside the air pocket; and
providing a resulting temperature reading by analyzing the plural temperature measurements made during the step of placing, wherein analyzing the plural temperatures measurements comprises:
storing a plurality of most recent temperature measurements in a moving time window;
successively calculating an average of up to all of the plurality of stored measurements;
calculating the difference between successive averages;
determining whether the difference is less than a predetermined value; and
outputting a calculated average temperature.
2. The method of claim 1 , wherein successively calculating the average of up to all of the plurality of stored measurements comprises discarding readings from the time window.
3. The method of claim 2 , wherein the discarded readings are selected from a group consisting of peak readings, high readings, and low readings.
4. The method of claim 1 , further comprising moving the time window upon determining that the difference is not less than the predetermined value, and wherein successively calculating the average of up to all of the plurality of stored measurements is performed upon determining that the difference is not less than the predetermined value.
5. The method of claim 1 , wherein outputting the calculated average temperature is performed upon determining that the difference is less than the predetermined value.
6. The method of claim 1 , wherein the stored plurality of most recent temperature measurements in the moving time window comprises calculated temperatures.
7. The method of claim 1 , wherein the radiation sensor comprises a thermopile sensor.
8. A method of detecting human body temperature, the method comprising:
detecting temperature at a forehead through plural temperature measurements, wherein the plural temperature measurements are made using a temperature detector comprising a radiation sensor which views a target surface area of the forehead, the temperature detector further comprising an extension for placement against the forehead. wherein the extension forms an air pocket isolating a portion of the forehead from air flow outside the air pocket: and
computing a body temperature as a function of ambient temperature and the detected temperature, wherein computing the body temperature comprises:
storing a plurality of most recent temperature measurements in a moving time window;
successively calculating an average of up to all of the plurality of stored measurements;
calculating the difference between successive averages;
determining whether the difference is less than a predetermined value; and
outputting a calculated average temperature.
9. The method of claim 8 , wherein successively calculating the average of up to all of the plurality of stored measurements comprises discarding readings from the time window.
10. The method of claim 9 , wherein the discarded readings are selected from a group consisting of peak readings, high readings, and low readings.
11. The method of claim 8 , further comprising moving the time window upon determining that the difference is not less than the predetermined value, and wherein successively calculating the average of up to all of the plurality of stored measurements is performed upon determining that the difference is not less than the predetermined value.
12. The method of claim 8 , wherein outputting the calculated average temperature is performed upon determining that the difference is less than the predetermined value.
13. The method of claim 8 , wherein the stored plurality of most recent temperature measurements in the moving time window comprises calculated temperatures.