Enhanced cooker hood with sensors for remote temperature measurement and presence detection
A device including a sensor is disclosed. In one embodiment, the sensor includes a thermal infrared sensor or a sensor based on CMOS-SOI-MEMS technology (also referred to as “TMOS”). The sensor is capable of performing at least two functions at the same time. The first is remote temperature measurement and the second is presence detection. The sensor passively collects infrared information and a microprocessor coupled to the sensor determines the temperature as well as presence.
1. A device comprising:
an infrared sensor having a field of view;
a processor coupled to the infrared sensor, the processor including:
a temperature determination circuit configured to determine a temperature of one or more objects on or adjacent to a heat generating structure within the field of view of the infrared sensor;
a presence determination circuit configured to detect presence within the field of view of the infrared sensor;
a compensation circuit configured to compensate the temperature based on a temperature of the processor and characteristics of the one or more objects on or adjacent to the heat generating structure in the field of view of the infrared sensor,
wherein the characteristics of the one or more objects include a type of a material and emissivity of the material, and
wherein the presence determination circuit is disabled in response to determining that the temperature compensated by the compensation circuit is below a safety temperature threshold.
2. The device according to claim 1 , wherein the sensor includes a CMOS-SOI transistor.
3. The device according to claim 1 , wherein compensating the temperature by the compensation circuit includes adjusting the temperature of the one or more objects based on an increased temperature of the processor caused by a heat flow from the one or more objects on and adjacent to the heat generating structure.
4. The device according to claim 1 , wherein the presence determination circuit is enabled in response to determining that the temperature compensated by the compensation circuit is above the safety temperature threshold.
5. The device according to claim 1 , wherein the sensor includes a first surface that is facing the heat generating structure, further comprising a lens on the first surface of the sensor to be arranged between the sensor and the heat generating structure,
wherein the lens coupled to the sensor adjusts the field of view of the sensor.
6. The device according to claim 5 , wherein the lens includes a semi-spherical lens.
7. A system, comprising,
a heat generating source;
a support structure above and aligned with the heat generating source, the support structure having a first surface facing the heat generating source;
a device on the first surface of the support structure, the device including:
a sensor having a field of view, the sensor configured to collect infrared data of one or more objects within the field of view, the sensor facing the heat generating source, the infrared data indicative of an intensity of infrared light;
a temperature determination circuit coupled to the sensor, the temperature determination circuit configured to determine temperature of the one or more objects within the field of view;
a compensation circuit configured to compensate temperature based on a temperature of a processor and emissivity of the one or more objects within the field of view; and
a presence determination circuit configured to detect presence within the field of view of the sensor,
wherein the presence determination circuit is disabled in response to determining that the temperature compensated by the compensation circuit is below a safety temperature threshold.
8. The system according to claim 7 , wherein the compensation circuit compensates a temperature of an object within the field of view of the sensor based on the following formula:
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wherein a temperature of an object is T obj , a collected infrared data from the object is Tobj raw , ε is emissivity of the object, Offset is an amount of offset which is a constant, a temperature of device is T asic , m, c, k, Ga, Fb are known coefficients, k corr is a correlation coefficient, and if i==0 then Tobj(° C.) i-1 =25 (° C.).
9. The system according to claim 8 , wherein the compensation circuit compensates temperature based on the correlation coefficient k corr by additionally adjusting the correlation coefficient k corr to the emissivity of the object.
10. The system according to claim 7 , wherein the presence determination circuit is enabled in response to determining that the temperature compensated by the compensation circuit is above the safety temperature threshold.
11. The system according to claim 7 , wherein a central point of an active area of the sensor is aligned with a central point of the heating generating source.
12. The system according to claim 11 , wherein the sensor includes a first surface that is facing the heat generating source, further comprising a lens on the first surface of the sensor to be arranged between the sensor and the heat generating source,
wherein the lens coupled to the sensor narrows the field of view of the sensor.
13. A method comprising:
receiving first infrared data from one or more objects within a field of view of a sensor;
determining a first temperature of the one or more objects using the first infrared data;
compensating the first temperature of the one or more objects based on a first temperature of a processor and characteristics of the one or more objects within the field of view of the sensor;
in response to determining that the first temperature of the one or more objects compensated based on the first temperature of the processor and the characteristics of the one or more objects within the field of view of the sensor is below a safety temperature threshold, disabling a presence determination circuit;
receiving second infrared data from the one or more objects within the field of view of the sensor;
determining a second temperature of the one or more objects using the second infrared data;
compensating the second temperature of the one or more objects based on a second temperature of the processor and the characteristics of the one or more objects within the field of view of the sensor;
in response to determining that the second temperature of the one or more objects compensated based on the second temperature of the processor and the characteristics of the one or more objects within the field of view of the sensor is above the safety temperature threshold:
enabling the presence determination circuit;
applying, by the presence determination circuit, a first low pass filter to the second infrared data and applying a second low pass filter to the second infrared data, the second low pass filter being different from the first low pass filter;
determining, by the presence determination circuit, presence signals based on a difference between an outcome of applying the first low pass filter to the second infrared data and an outcome of applying the second low pass filter to the second infrared data;
comparing, by the presence determination circuit, the presence signals with a difference of a presence threshold and a hysteresis threshold; and
determining, by the presence determination circuit, a presence of a subject within the field of view based on the comparing the presence signals with the difference of the presence threshold and the hysteresis threshold.
14. The method of claim 13 , determining that the subject is present when the presence signals are greater than the difference of the presence threshold and the hysteresis threshold.
15. The method of claim 13 , determining that the subject is absent when the presence signals are smaller than the difference of the presence threshold and the hysteresis threshold.
16. The method of claim 14 , further comprising:
transmitting a notification signal in response to the presence signals being greater than the difference of the presence threshold and the hysteresis threshold.