Auto detection system based on thermal signals

There is provided an auto detection system including a thermal detection device and a host. The host controls an indication device to indicate a prompt message or detection results according to a slope variation of voltage values or 2D distribution of temperature values detected by the thermal detection device, wherein the voltage values include the detected voltage of a single pixel or the sum of detected voltages of multiple pixels of a thermal sensor.

BACKGROUND

1. Field of the Disclosure

This disclosure generally relates to an auto detection system and, more particularly, to an auto detection system that performs the electronic device control and message prompting based on thermal signals.

2. Description of the Related Art

In the image processing technology nowadays, it is able to perform various automatic controls according to images acquired by an image sensor, e.g., performing the ID recognition using images to accordingly control the corresponding electronic devices.

However, the privacy protection is gradually considered an important issue. Accordingly, in a public area, unless being used as a monitor device, the image sensor is no longer suitable to be used as an automatic control means. In addition, although a pyroelectric infrared (PIR) motion sensor has been broadly applied to the lamp control means as an automatic switch to save power by turning off the lamp in an area when there is no person in that area, the PIR motion sensor can lose its function when an object in the detected area thereof has no motion due to that the PIR motion sensor is essentially functioned to detect a moving object.

Accordingly, the present disclosure provides an auto detection system without using an image sensor or a PIR motion sensor and can be applied to the human detection in an elevator, the urine-wet detection, the stove detection, the hair temperature detection and the skin temperature detection.

SUMMARY

The present disclosure provides an auto detection system that identifies whether there is a person in an elevator cabin according to the slope of digital values, the fluctuation of digital values and the variation of temperatures outputted by a thermal sensor chip.

The present disclosure further provides an auto detection system that identifies a urine-wet condition of a diaper according to the slope of digital values outputted by a thermal sensor chip.

The present disclosure further provides an auto detection system that controls a display to show a 2D temperature distribution of multiple temperature values outputted by a thermal sensor chip as a reference for a user in cooking.

The present disclosure provides an auto detection system including an elevator cabin, at least one thermal detection device and a host. The at least one thermal detection device is configured to output digital values and object temperatures at a predetermined frequency. The host receives the digital values and the object temperatures, and is configured to calculate a slope between two digital values, calculate a fluctuation degree of multiple digital values, calculate a temperature variation of the object temperatures, and identify whether the elevator cabin has a person therein or not according to the slope, the fluctuation degree and the temperature variation.

The present disclosure further provides an auto detection system including a diaper, a thermal detection device and a host. The thermal detection device is arranged on the diaper and configured to output digital values at a predetermined frequency. The host receives the digital values and is configured to calculate a slope between two digital values, and generate a prompt signal when the slope calculated according to continuous digital values is within a predetermined range for a predetermined time interval.

The present disclosure further provides an auto detection system including a stove, a thermal detection device and a host. The thermal detection device has a field of view covering the stove and is configured to output object temperatures at a predetermined frequency. The host receives the object temperatures and is configured to control at least one of an extraction fan, the stove and a display device according to the object temperatures.

In the present disclosure, the thermal sensor includes a single thermopile sensor (i.e. outputting one voltage signal once) or a thermopile sensor array (i.e. outputting multiple voltage signals per frame). The thermal detection device includes an addition circuit used to perform the binning on multiple voltage signals outputted by multiple pixels of the thermal sensor. The voltage sum is then processed by the analog-digital-conversion so as to improve the signal-to-noise ratio and accuracy.

DETAILED DESCRIPTION OF THE EMBODIMENT

The present disclosure provides an auto detection system that performs the electronic device control or the message prompting according to voltage signals or values outputted by a single thermopile sensor or a thermopile sensor array without using an image sensor or a pyroelectric infrared (PIR) motion sensor thereby solving the problems of privacy protection and steady object detection.

Referring toFIG. 1, it is a cross-sectional view of a package of thermal sensor array10according to one embodiment of the present disclosure. The package of thermal sensor array10includes a circuit board11, a sensor array integrated circuit13, a package15and a filter17. The sensor array integrated circuit13has multiple sensing elements (or called pixels)130arranged in a matrix, e.g.,FIGS. 3A to 3Dshowing 8×8 sensing elements. The filter17is used to block light spectrum outside far infrared light. When the sensing elements130absorb far infrared light, a potential difference is formed at two terminals of the element to output a voltage signal as a detected signal. Each of the sensing elements130is, for example, a thermopile sensor, wherein the principle of a thermopile sensor that receives far infrared light to output a voltage signal is known to the art and thus details thereof are not described herein. Accordingly, the multiple sensing elements130of the package of thermal sensor array10output multiple voltage signals or voltage values to form a frame.

It should be mentioned that althoughFIG. 1shows only one set of sensor array integrated circuit13, the present disclosure is not limited thereto. In the case that a larger detection range is required, the package of thermal sensor array10includes multiple sets of sensor array integrated circuits13to output multiple sets of voltage signals or voltage values, and details thereof are referred to a U.S. patent application Ser. No. 16/294,873, file on Mar. 6, 2019 and entitled “FAR INFRARED SENSOR APPARATUS HAVING MULTIPLE SENSING ELEMENT ARRAYS INSIDE SINGLE PACKAGE”, assigned to the same assignee of the present disclosure, and the full disclosure of which is incorporated herein by reference.

Referring toFIG. 2, it is a schematic block diagram of a thermal detection device200according to one embodiment of the present disclosure. The thermal detection device200is formed as, for example, a chip package that is encapsulated by a casing to form a device similar to a camera, but not limited to. The thermal detection device200includes a thermal sensor201, a row decoder202, a column decoder (shown as col. decoder)203, an amplifier204, an addition circuit (shown as addition ckt.)205, an analog-to-digital converter (ADC)206, a first calibration calculating circuit207, a second calibration calculating circuit208, and an ambient temperature sensor (shown as ambient T sensor)209.

The thermal sensor201includes, for example, the package of thermal sensor array10mentioned above. According to control signals of the row decoder202and the column decoder203, voltage signals or voltage values Vobj of every pixel are sequentially readout (by scanning and sampling procedure) from the thermal sensor201, wherein the method of scanning a pixel array according to the control signals of a row decoder and a column decoder is known to the art and thus details thereof are not described herein.

In the present disclosure, the thermal sensor201is used to detect far infrared light generated from the object within a field of view thereof. The ambient temperature sensor209is selected from, for example, the temperature meter other than the far infrared sensor. The ambient temperature sensor209is used to detect ambient temperature surrounding the thermal detection device200and output voltage signals or voltage values Vamb to the ADC206, wherein by using different types of temperature meters, the ambient temperature sensor209generates a current signal at first and then the current signal is converted to the voltage signal Vamb. The detection frequency of the thermal sensor201is arranged to be identical to or different from the detection frequency of the ambient temperature sensor209.

The amplifier204is, for example, a programmable game amplifier (PGA) that is used to amplify the voltage signal or value Vobj outputted by the thermal sensor201. It should be mentioned that althoughFIG. 2shows only one amplifier204, the present disclosure is not limited thereto. The thermal detection device200includes multiple amplifiers204respectively coupled to one pixel row for amplifying the voltages on the connected pixel row.

The addition circuit205is used to perform the binning or summation of values of multiple voltage signals generated by the thermopile sensor array, if being adopted, to achieve the purposes of improving the signal-to-noise (SNR) and increasing amplitude of the voltage signal to improve the resolution. In the present disclosure, a pixel number or pixel region that the addition circuit205performs the binning thereof is determined according to different applications. For example, inFIG. 3A, the addition circuit205performs the binning of voltage signals of all pixels (e.g., 8×8 pixel array being taken as an example herein) to obtain one voltage sum to be outputted to the ADC206; inFIG. 3B, the addition circuit205performs the binning of voltage signals of a central 4×4 window and the voltage signals of other pixels outside the 4×4 window is maintained as they are, e.g., obtaining one voltage sum associated with the 4×4 window and 48 voltage signals associated with every single pixel to be outputted to the ADC206; inFIG. 3C, the pixel array is divided into 16 regions and the addition circuit205performs the binning of 4 voltage signals at each region to obtain 16 voltage sums to be outputted to the ADC206; and inFIG. 3D, the pixel array is divided into 4 regions and the addition circuit205performs the binning of 16 voltage signals at each region to obtain 4 voltage sums to be outputted to the ADC206. It is appreciated that the binning shown inFIGS. 3A to 3Dis only intended to illustrate but not to limit the present disclosure.

The ADC206is used to convert each voltage signal Vobj or each voltage sum from the addition circuit205to a digital code, each digital code has a digital value. The ADC206is further used to convert the voltage signal or voltage value Vamb into the digital signal. The ADC206may generate a number of digital values associated with Vobj different from a number of digital values associated with Vamb within the same time interval.

The first calibration calculating circuit207is used to convert the digital value associated with the voltage signals without the binning to the temperature signal, e.g., the digital value associated with one voltage signal Vobj or Vamb corresponding to one temperature value or the digital values associated with multiple voltage signals Vobj or Vamb corresponding to one identical temperature value (in the case that the resolution of digital value being larger than the resolution of temperature value). The thermal detection device200preferably further has a memory210used to previously record the corresponding relationship or algorithm between the digital value (or digital code) and the temperature value such that when the digital value of one voltage signal Vobj or Vamb is received from the ADC206, a corresponding temperature value Tobj or Tamb is calculated by the first calibration calculating circuit207.

The second calibration calculating circuit208is used to convert the digital value associated with the voltage sum obtained by the binning (e.g., adding the values of multiple voltage signals) to the temperature signal, e.g., the digital value associated with one voltage sum corresponding to one temperature value or the digital values associated with multiple voltage sums corresponding to one identical temperature value. As the binned voltage sum and the voltage signal without the binning have different conditions, the second calibration calculating circuit208is further provided to perform the conversion from digital values to temperature values. The memory210preferably further records the corresponding relationship or algorithm between the digital value (or digital code) of voltage sum and the object temperature Tobj such that when the digital value of one voltage sum is received from the ADC206, a corresponding temperature value is calculated by the second calibration calculating circuit208. In one non-limiting aspect, the second calibration calculating circuit208outputs only the object temperature Tobj without outputting the ambient temperature Tamb.

The thermal detection device200includes, for example, a multiplexer or a switching element used to transfer the digital value of voltage signals to the first calibration calculating circuit207, and transfer the digital value of voltage sums to the second calibration calculating circuit208. In one non-limiting aspect, the thermal detection device200includes two ADC used to convert the digital signal of Vobj and Vamb, respectively.

Accordingly, the thermal detection device200outputs digital values (associated with Vobj only), object temperatures Tobj and ambient temperatures Tamb at predetermined frequencies identical to or different from one another, wherein the predetermined frequency is, for example, 1 to 3 times per second according to different applications. In the present disclosure, the digital value outputted by the thermal detection device200includes the detection result of the thermal sensor201to be used later (described below by an example) without the detection result of the ambient temperature sensor209. The detection result of the ambient temperature sensor209is outputted as ambient temperature Tamb, which is converted by the first calibration calculating circuit207.

The thermal detection device200of the present disclosure further includes other circuits such as a power management circuit and an oscillation circuit, and details thereof are known to the art and thus not described herein. Different applications of the thermal detection device200are described hereinafter.

Referring toFIG. 4, it is a schematic block diagram of an auto detection system400according to one embodiment of the present disclosure. The auto detection system400includes a thermal detection device200and a host40coupled to each other in a wired or wireless manner to communicate therebetween. The thermal detection device200may use that shown inFIG. 2, and is arranged, for example, on an electronic device46to output digital values, object temperatures Tobj and ambient temperatures Tamb according to the detection result thereof. The host4is a computer device equipped with a central processing unit (CPU) and/or a microcontroller unit (MCU) such as, for example, a desktop computer, a notebook computer, a tablet computer, a smart phone, a central server or the like. The host4is directly integrated with a display device42and/or a speaker44, or coupled with the display device42and/or the speaker44in a wired or wireless manner. In this way, the host4receives the digital values, object temperatures Tobj and ambient temperatures Tamb from the thermal detection device200to control the display device42, the speaker42and/or the electronic device46, which is, for example, a device that the thermal detection device200is applied to.

Referring toFIG. 5, it is a schematic diagram of the application of an auto detection system400according to a first embodiment of the present disclosure. In the first embodiment, at least one thermal detection device200(e.g.,5thermal detection devices being shown inFIG. 5at different positions) is arranged at a ceiling or close to the ceiling of an elevator cabin50, and each thermal detection device200has its own field of view FOV (for simplification only one being shown). In the first embodiment, as the auto detection system400is used to detect whether the elevator cabin50has a person therein or not, the FOV of the thermal detection device200preferably covers only an inside area of the elevator cabin50without covering the area outside an entrance (i.e. outside the elevator) of the elevator cabin50. In the present disclosure, the thermal detection device200is preferably arranged at two sides above the entrance or at a central area of the ceiling of the elevator cabin50. Preferably, the field of view FOV of the thermal detection device200does not cover the entrance of the elevator cabin50to reduce the influence from the opening and closing of the cabin door.

As mentioned above, each thermal detection device200outputs digital values, object temperatures Tobj and ambient temperatures Tamb respectively at a predetermined frequency to the host40. The host40is located, for example, at a central control room, a guardroom or held by a staff outside the elevator cabin50for the staff to monitor whether there is a person in the elevator cabin50or not via the display device42, the speaker44, lamps or other indicating means. In the present disclosure, the display device42does not show the inner image of the elevator cabin50, and the indication of whether there is a person in the elevator cabin50or not is shown by words or graphs on the display device42for the privacy protection.

In the first embodiment, the thermal detection device200includes a single thermopile sensor or a thermopile sensor array. For the thermopile sensor array case, the thermal detection device200has a pixel array (e.g.,201) for outputting multiple voltage signals Vobj (or called a frame) every sampling period. As mentioned above, the addition circuit205is used to sum up a part or all of the multiple voltage signals Vobj (more specifically the amplified voltage signals) to generate a voltage sum(s). The ADC206is used to convert the voltage signal Vobj and the voltage sum into the digital value. The first calibration calculating circuit207is used to convert and output the object temperature Tobj according to the digital value associated with the voltage signal Vobj. The second calibration calculating circuit208is used to convert and output the object temperature Tobj according to the digital value associated with the voltage sum. It is appreciated that the resolution of the digital value is determined by the resolution of the ADC206, e.g., 0-255, but not limited to.

After receiving the detection result from the thermal detection device200, the host40calculates a slope between two digital values, a fluctuation degree of multiple digital values and a temperature variation of the object temperatures Tobj corresponding to each thermal detection device200, and then identifies whether the elevator cabin50has a person therein or not according to the calculated slope, fluctuation degree and temperature variation. The host40performs the identification according to the outputted parameter of each thermal detection device200, respectively, to obtain multiple identification results. The method of identifying the existence of a person according to one thermal detection device200is illustrated hereinafter.

Referring toFIG. 6, it is a schematic diagram of a variation of the object temperature Tobj when there is a person and no person in an elevator cabin50. It is seen fromFIG. 6that when a person enters or leaves the elevator cabin50, the object temperature Tobj changes to have a temperature variation, e.g., ΔT1, ΔT2and ΔT3, wherein values of ΔT1, ΔT2and ΔT3are identical to or different from each other according to the human height, human body temperature, ambient temperature or other environmental conditions. When the temperature variation (increment or decrement) exceeds a temperature threshold, it is able to identify a person in/out. In the present disclosure, the temperature variation is, for example, a difference between two adjacent (in timeline) object temperatures Tobj outputted by the thermal detection device200, two object temperatures Tobj separated by a predetermined time interval, or a difference between a current object temperature (e.g., at time t2) outputted by the thermal detection device200and a recorded object temperature (e.g., at time t1) stored when the elevator cabin50has no person therein.

In other words, the host40preferably includes a memory401used to record an object temperature Tobj when there is no person in the elevator cabin50(e.g., at time t1) as a reference temperature to avoid error caused by the ambient temperature variation. The host40updates the reference temperature every predetermined time when the elevator cabin50continuously has no person therein, or the host40updates the reference temperature (e.g., at time t3) after a person(s) enters and leaves the elevator cabin50to increase the identification accuracy.

However, it is noticed that there are many reasons that can influence the object temperature Tobj. Accordingly, the present embodiment further uses other detected parameters in addition to the object temperature Tobj to identify whether the elevator cabin50has a person therein or not.

Referring toFIG. 7A, it is a schematic diagram of the digital value (associated with the voltage signal Vobj or voltage sum) fluctuation (indicated by solid line) and the slope variation (indicated by dotted line) when there is no person in an elevator cabin50. The reason of using the digital value to perform the identification is that the resolution of digital value can be set to be larger than the resolution of temperature value to obtain more accurate identification result.

In the first embodiment, the host40calculates a slope between two digital values, wherein said two digital values are two adjacent (in timeline) digital values outputted by the thermal detection device200. As mentioned above, the thermal detection device200is set to output 1 to 3 digital values per second. When the slope between two digital values exceeds a slope threshold value or a slope threshold range, e.g., TH1and TH2inFIG. 7A, it means that the door of the elevator cabin50is opened and a person might enter or leave the elevator cabin50. It is seen fromFIG. 7Athat when the door of the elevator cabin50opens and closes, the slope have an obvious change (e.g., exceeding a threshold).

In addition, to increase the identification accuracy, the host40further identifies whether a fluctuation degree of multiple digital values exceeds a code variation threshold. For example, the fluctuation degree is preferably a standard deviation, shown as Stdev inFIG. 7A, of multiple digital values within a predetermined time interval after the slope between the two digital values exceeds the slope threshold. In one aspect, Stdev is a standard deviation of multiple digital values within the predetermined time interval after the slope changes back to be within a predetermined threshold range (e.g., between TH1and TH2). It is seen fromFIG. 7Athat the slope exceeds the predetermined threshold range when the cabin door opens and then goes back to be within the predetermined threshold range after the cabin door closes.

Referring toFIG. 7Btogether, it is a schematic diagram of the digital value fluctuation (indicated by solid line) and the slope variation (indicated by dotted line) when there is a person in an elevator cabin50. It is seen fromFIGS. 7A and 7Bthat the slope between two digital values exceeds the predetermined threshold range (e.g., between TH1and TH2) when the door of the elevator cabin50opens (no matter whether there is a person entering or leaving) and then goes back to be within the predetermined threshold range after the cabin door closes. Accordingly, it is not easy to identify the entering/leaving person only according to the slope variation. But it is seen fromFIGS. 7A and 7Bthat when there is a person in the elevator cabin50, the fluctuation degree Stdev of multiple digital values (e.g.,FIG. 7B) within a predetermined time interval (e.g., 3-10 seconds, but not limited to) is larger than the fluctuation degree Stdev when there is nobody in the elevator cabin50(e.g.,FIG. 7A). The reason is considered that the person in the elevator cabin50causes a larger disturbance to the temperature. Accordingly, the first embodiment performs the human identification using 3 parameters to effectively improve the identification accuracy. In the case ofFIGS. 7A and 7B, a code variation threshold is set, for example, as 1.0 code.

It should be mentioned that the fluctuation degree is not limited to be calculated by using the standard deviation, and may be obtained by calculating other parameters that can be used to indicate the fluctuation of the digital values.

Referring toFIG. 8, it is an operational flow chart of an auto detection system400according to a first embodiment of the present disclosure, including the steps of: generating temperature values and digital codes (Step S81); comparing a code slope with a slope threshold THa (Step S82); comparing a code fluctuation with a code variation threshold THb (Step S83); comparing a temperature variation with a temperature threshold THc (Step S84); and identifying whether an elevator cabin has a person or not (Steps S85-S86), wherein THa, THb and THc indicate a single value or a value range, respectively.

Referring toFIGS. 4 to 8together, the thermal detection device200firstly sends the detected digital values (i.e. values of digital codes) and object temperatures Tobj to the host40, Step S81.

In this embodiment, the host40identifies the elevator cabin50having a person therein only when the slope between two digital values exceeds a slope threshold or threshold range (referring toFIGS. 7A and 7B), the fluctuation degree Stdev of multiple digital values exceeds a code variation threshold or threshold range (referring toFIGS. 7A and 7B), and the temperature variation exceeds a temperature threshold or threshold range (referring toFIG. 6), Step S82-S85. When any one of the Steps S82-S84is not true, the elevator cabin50is identified having no person therein, Step S86.

No matter what is the identification result, the host40indicates whether the elevator cabin50has a person or not via a coupled indication device (e.g., display device42, speaker44and/or lamp), or via a coupled mobile device (e.g., smart phone or smart watch).

In this embodiment, the host40further detects whether the temperature in the elevator cabin50is normal or abnormal according to the ambient temperature Tamb. If the ambient temperature Tamb is too high or too low, a warning message is indicated via the indication device or the mobile device. In addition, the host40further adjusts the slope threshold, the code variation threshold and/or the temperature threshold according to the ambient temperature Tamb to eliminate the interference brought by the environment change.

In one non-limiting embodiment, if the auto detection system400includes more than one thermal detection device200. When identifying that the elevator cabin50has a person therein according to one of the multiple thermal detection devices200, the host40identifies that the elevator cabin50is occupied by a person(s). The host40is not necessary to identify the elevator cabin50being occupied after all thermal detection devices200are identified to have a person therein.

In one non-limiting embodiment, if the auto detection system400includes a thermopile sensor array. When identifying that the elevator cabin50has a person therein according to a predetermined number of pixels or pixel regions (e.g., sub-regions shown inFIGS. 3C-3D) of a pixel array of the thermopile sensor array, the host40identifies that the elevator cabin50is occupied by a person(s), wherein the predetermined number is smaller than a pixel number or a region number of the pixel array. The host40is not necessary to identify the elevator cabin50being occupied after all pixels or pixel regions are identified to have a person therein. The method of identifying a person based on each pixel or pixel region is referred toFIG. 8.

In another non-limiting aspect, one pixel of the thermopile sensor array is turned on at first, and when the object temperature Tobj detected by the one pixel exceeds a temperature threshold, the rest pixels are then turned on.

In the first embodiment, after the elevator cabin50is identified to have a person in Step S85, the host40continuously identifies whether the person leaves or not according the digital values and object temperatures Tobj sent from the thermal detection device200based on the Steps S82and S83. For example inFIG. 7B, when the cabin door is opened and a person leaves the elevator cabin50, the curves inFIG. 7Bchange toFIG. 7Ato cause the fluctuation degree Stdev to be smaller than THb. In this way, the host40confirms that the elevator cabin50has no person therein. The host40further confirms that a person leaves the elevator cabin50according toFIG. 6. As mentioned above, the host40updates the reference temperature of the elevator cabin50(as shown inFIG. 6temperatures at times t1and t3having different values) to be used in the next round of identification.

In other aspects, the auto detection system400further includes at least one thermal detection device200arranged outside the elevator cabin50to monitor the elevator shaft to identify whether there is a person in the elevator shaft.

Referring toFIG. 9, it is a schematic diagram of an auto detection system400according to a second embodiment of the present disclosure. In this embodiment, the auto detection system400is applied to the urine-wet detection of a diaper. Compared with the conventional urine-wet detection by using a moisture sensor, the casing of the auto detection system400of the present disclosure does not have an opening to allow the moisture to come in such that an enclosed structure is formed without being influenced by the sweat moisture. The thermal detection device200is arranged at different positions to be suitable for male products or female products.

The auto detection system400of this embodiment also includes a thermal detection device200and a host40coupled to each other. As shown inFIG. 9, the thermal detection device200is arranged on the diaper90and used to output digital values at a predetermined frequency. In this embodiment, the auto detection system400outputs or does not output object temperatures Tobj according to different applications. The thermal detection device200also includes a single thermopile sensor or a thermopile sensor array without particular limitations. When the thermal detection device200adopts the thermopile sensor array, the thermal detection device200also performs the aforementioned binning procedure on a part of or all multiple voltage signals outputted by the thermal sensor201thereof.

The host40communicates with the thermal detection device200in a wired or wireless manner. Examples of the thermal detection device200and the host40have been described above, and thus only the operating method thereof are described hereinafter.

Referring toFIG. 10, it is an operational flow chart of an auto detection system400according to a second embodiment of the present disclosure, including the steps of: generating digital codes (Step S101); comparing a code slope with a slope threshold THs (Step S102); conforming whether a continuous time exceeds a time threshold THt (Step S103); and determining whether to give a warning or not (Steps S104-S105).

Step S101: The thermal detection device200disposed in the diaper90has, for example, a press button or a switch. When the diaper90is worn on a human body, the thermal detection device200is activated to operate by using the press button or the switch; or the thermal detection device200starts to operate after a connection between the thermal detection device200and the host40is accomplished. Then, the host40receives the digital values generated by the ADC206of the thermal detection device200. In this embodiment, the digital values are associated with the voltage signal or the voltage sum depending on the type of the thermopile sensor being used. As it is possible to set the digital values to have higher resolution than the object temperatures Tobj, the digital value is selected for the urine-wet detection. According to different implementation, the host40further receives object temperatures Tobj from the thermal detection device200for double check or other identifications.

Step S102: After receiving the digital values sequentially, the host40(e.g., the processor thereof) calculates a slope between two digital values to be compared with a slope threshold THs. In one aspect, a time interval for calculating the slope between the two digital values is between, for example, 0.5 and 1.5 seconds i.e., a period of outputting the digital values is between 0.5 and 1.5 seconds. Preferably, when a different time interval is selected, the slope threshold THs is also changed. When the slope is larger than the slope threshold THs, the Step S103is entered; otherwise the Step S105is entered and no warning is provided.

In another aspect, the host40identifies whether the calculated slope is between a predetermined range, e.g., larger than the slope threshold THs and smaller than another slope threshold. The another slope threshold is for preventing error due to the slope variation caused by other reasons since the urine temperature is generally between a predetermined range.

Step S103: When identifying that the slope between two digital values is larger than a slope threshold THs or within a predetermined range, the host40then identifies whether the slopes between multiple sets of two digital values within a predetermined time interval (e.g., 5-7 seconds) are continuously larger than the slope threshold THs or within the predetermined range. When the calculated multiple slopes are larger than the slope threshold THs or within the predetermined range longer than the time interval THt, the Step S104is entered; otherwise the Step S105is entered and no warning is provided. In this embodiment, the urine-wet is confirmed only when multiple slopes are larger than the slope threshold THs or within the predetermined range for a predetermined time interval so as to avoid error due to the sensor falling off or diaper being taken off.

In another aspect, the predetermined ranges of the slope in Steps S102and S103are different. For example, in Step S103the predetermined range is set as THl1<slope<Thu1, and in Step S103the predetermined range is set as THl2<slope<Thu2, wherein Thu1>Thu2and THl1<THl2, but not limited thereto.

Step S104: The host40generates a prompt signal to the indication device, e.g., the display device42and/or the speaker44, or to a mobile device, e.g., a smart phone, to indicate a prompt message, e.g., changing a new diaper.

In some aspects, the thermal detection device200further outputs object temperatures Tobj or ambient temperatures Tamb to the host40. The host40generates a warning signal when the object temperatures Tobj or the ambient temperatures Tamb exceed a predetermined range. For example, when the object temperatures Tobj or the ambient temperatures Tamb are too high, e.g., much higher than the urine temperature (e.g., Tobj or Tamb=40 to 45 degrees), the host40informs the indication device or the mobile device, using the warning signal, to generate a warning message such as images or sounds.

In addition, the host40of the second embodiment further double checks the urine-wet condition in conjunction with the fluctuation, difference, slope, waveform or the standard deviation of the object temperatures Tobj and/or the digital values within a predetermined time interval.

In addition, the host40of the second embodiment further identifies the wearing state of the diaper90according to whether the object temperature Tobj and/or the digital value is within a predetermined operation range.

Referring toFIG. 11, it is a schematic diagram of an auto detection system400according to a third embodiment of the present disclosure. In this embodiment, the auto detection system400is applied to the stove detection in the kitchen, e.g., overheating, forgetting to turn off the stove, cooking assistance or the like. The auto detection system400includes at least one thermal detection device200. A number of the thermal detection device200is determined according to the area to be detected without particular limitations.

The auto detection system400of this embodiment also includes a thermal detection device200and a host40coupled to each other. The thermal detection device200has a field of view FOV covering the stove100and outputs object temperatures Tobj at a predetermined frequency. It should be mentioned that althoughFIG. 11shows that the thermal detection device200is arranged right above the stove100, the present disclosure is not limited thereto. The thermal detection device200may be arranged at any suitable angle as long as the FOV thereof covers the stove100, and the stove100is not limited to heat a pot.

The host40is coupled to the thermal detection device200in a wired or wireless manner to receive object temperatures Tobj for controlling an extraction fan, the stove fire, a display device and/or other equipment in the kitchen according to the object temperatures Tobj. The host40is wired or wirelessly coupled to the electronic device46or integrated therein.

In one non-limiting aspect, the host40and the thermal detection device200are both integrated in the extraction fan. The host40is used to turn on the extraction fan when identifying that the object temperature Tobj exceeds a room temperature threshold (indicating the stove being turned on). The host40is further used to automatically adjust the wind strength of the extraction fan according to a variation of the object temperature Tobj (indicating the stove changing). In the case that the host40are separated from the extraction fan, the host400still automatically controls the extraction fan in a wired or wireless manner or informs a user to turn on the extraction fan via a display device42.

In another non-limiting aspect, the host40is further used to control the indication device (e.g., including the display device42and/or speaker44) to show a warning message when identifying that the object temperature Tobj exceeds a high temperature threshold, wherein the indication device is embedded in the host40or the electronic device46, or separated therefrom.

In another non-limiting aspect, the host40turns off the stove when identifying that the FOV of the thermal detection device200does not have any movement of a human body for a predetermined time interval. In this aspect, the thermal detection device200preferably includes a thermopile sensor array for outputting a thermal frame containing multiple object temperatures Tobj (e.g., each pixel outputting one object temperature) at a predetermined frequency. The host40controls the display device according to the thermal frame to show the multiple object temperatures by a 2-dimensional (2D) image, as shown inFIGS. 12A and 12Bfor example. InFIG. 12A, each rectangular region indicates a detected value of one pixel or one pixel region. For example, the display device42directly shows the object temperatures Tobj (e.g., values in every rectangular region inFIG. 12A) at the corresponding regions. In other aspects, the display device42shows high/low temperatures by different colors or brightness asFIG. 12Bwithout showing values of the object temperatures Tobj.

In this way, the host40performs various identifications and gives a corresponding prompt message according to the thermal frame or the 2D image. For example, if the thermal frame or the 2D image does not contain the movement of a heating object (e.g., including a human body or heated shovel), it is identified that the FOV of the thermal detection device20does not have movement of a human body.

For example, in preheating a pot, when identifying that at least one of the multiple object temperatures Tobj of the thermal frame is larger than or equal to a heating threshold, the host40controls the indication device to indicate the message of a target temperature being reached so as to remind the user to put ingredients in the pot. For example, when identifying that the uniformity of the multiple object temperatures Tobj of the thermal frame is lower than a uniformity threshold, the host40controls the indication device to show the message of nonuniform temperature to remind the user to turn over the ingredients.

If the display device42shows a current temperature distribution real-timely asFIGS. 12A and 12B, the user can know the current operation temperature through the display device42.

In one non-limiting aspect, the thermal detection device200further outputs ambient temperatures Tamb to the host40. When identifying that the ambient temperatures Tamb exceed a predetermined temperature threshold, the host40controls the cooling equipment such as a cooling fan or air conditioner to decrease the temperature in the kitchen.

It is appreciated that the numbers, including temperatures, digital values, pixel numbers and thresholds, mentioned in the above embodiments are only intended to illustrate but not to limit the present disclosure. Although the above embodiments are described in the way that the host40informs only the display device, a speaker and/or a mobile device as examples, the present disclosure is not limited thereto. In other aspects, the host40informs other electronic devices in a smart home according to the calculated and identified results.

For example, the thermal detection device200of the present disclosure is arranged on a hair dryer for detecting the hair temperature during operation to accordingly adjust the wind strength and/or the wind temperature, e.g., by adjusting the current flowing through the heating wire of the hair dryer. When the hair temperature (e.g., identified by the host40according to the object temperature Tobj) exceeds a predetermined temperature threshold, the wind strength and/or the wind temperature is decreased to prevent the hair from being damaged. On the contrary, the wind strength and/or the wind temperature is increased.

For example, the thermal detection device200of the present disclosure is arranged on an electric radiator for detecting the skin temperature during operation to accordingly adjust the radiation temperature and/or the wind temperature, e.g., by adjusting the current flowing through the heating wire of the electric radiator. When the skin temperature (e.g., identified by the host40according to the object temperature Tobj) exceeds a predetermined temperature threshold, the radiation temperature and/or the wind temperature is decreased to improve the user experience. On the contrary, the radiation temperature and/or the wind temperature is increased.

In one aspect, the thermal detection device200of the present disclosure is used as an optical sensor320or520inFIGS. 13-19to be arranged on a circuit board and covered by a front cover.

FIGS. 13, 14, 15 and 16are schematic diagrams of an optical sensor assembly300according to one embodiment of the present disclosure. The optical sensor assembly300includes a circuit board310(e.g., a printed circuit board or a flexible circuit board), an optical sensor320, a connector330, and a front cover340.FIG. 13is a side view of the circuit board310, the optical sensor320, and the connector330.FIG. 14is a rear view of the front cover340.FIG. 15is a front view of the front cover340attached to the circuit board310.FIG. 16is another view of the circuit board310on which the front cover340is not yet attached. The connector330is attached to a back surface352of the circuit board310, and the front cover340is attached to a front surface351of the circuit board310.

The optical sensor320is positioned on and electrically connected to the circuit board310. The connector330is positioned on the circuit board310. The connector330is used to transmit electrical signals to and from the optical sensor320. In addition, the connector330is used to transmit electrical signals between the optical sensor320and an external electronic device that adopts the optical sensor assembly300. The front cover340is attached to the circuit board310and covers the optical sensor320. The front cover340includes an optical element345used to allow incident light of a predetermined wavelength to transmit through the optical element345and condense the incident light onto the optical sensor320. The optical element345is a convex lens or a Fresnel lens.

In one embodiment, an outer surface353of the optical element345is a plane surface, and the convex lens or the Fresnel lens is formed at an inner surface354of the optical element345.

However, the present disclosure is not limited thereto. In one non-limiting aspect, the optical element345is a transparent layer used to guide incident light to the optical sensor320without condensing or diverging the incident light.

It should be mentioned that althoughFIG. 15shows that the outer surface353of the optical element345is substantially parallel to the front surface351of the circuit board310, the present disclosure is not limited thereto. According to an incident direction of the incident light, the outer surface353of the optical element345is preferably tilted to be perpendicular to the incident direction.

In one embodiment, the front cover340, including the optical element345, is made of polypropylene or polyethylene. The whole front cover340, including the optical element345, is produced via injection molding as a single piece. However, the present disclosure is not limited thereto. In one non-limiting aspect, the optical element345is formed separately from the front cover340, and then squeezed into the front cover340.

In another embodiment, the optical element345includes at least one of a polypropylene film, a polyethylene film, a silicon film, a germanium film, and a diamond-like carbon film.

In one embodiment, the optical sensor320is a far infra-red thermal sensor used to detect a temperature of a thermal source. The aforementioned predetermined wavelength of the incident light is in a range from 8 micrometers to 12 micrometers, and the optical element345is used to allow the incident light to transmit through the optical element345with a transmittance in a range from 20% to 80%.

In another embodiment, the optical sensor320is an ambient light sensor. The aforementioned predetermined wavelength of the incident light is in a range from 390 nanometers to 700 nanometers.

The optical sensor320generates electrical signals by detecting the incident light penetrating the optical element345. The connector330transmits the electrical signals to a processor of an electronic device for predetermined control.

In one non-limiting aspect, the front cover340further includes at least one alignment peg341(e.g., two alignment pegs341being shown inFIG. 14), and the circuit board310includes at least one alignment hole342(e.g., two alignment hole342being shown inFIG. 15) used to receive the at least one alignment peg341, and the at least one alignment peg341is formed integrally with the front cover340. The front cover340further includes at least one screw hole343used to receive at least one screw for attaching and fixing the front cover340to the circuit board310.

In the embodiment shown inFIGS. 14, 15 and 16, the front cover340includes two alignment pegs341and two screw holes343, and the circuit board310includes two alignment holes342. In another embodiment, the front cover340includes more or less alignment pegs341and more or less screw holes343, and the circuit board310includes more or less alignment holes342.

The front cover340further includes a receiving cavity347used to accommodate the optical sensor320attached on the circuit board310. The front cover340is attached to the circuit board310via a water-proof and dust-proof adhesive, so that the circuit board310, the adhesive, and the front cover340around the receiving cavity347form a sealed enclosure for accommodating and protecting the optical sensor320from various hazards of the ambient environment, such as water, dust, electrical damage and mechanical damage. In the aspect that the front cover340is combined with the circuit board310via adhesive, the at least one screw hole343is not implemented.

It should be mentioned that although the front cover340is shown to have curved edges between two protruding ends, it is only to illustrate but not to limit the present disclosure. In other embodiments, the front cover340has other shapes such as a rectangular shape according to a receiving opening of the electronic device adopting the optical sensor assembly300.

FIGS. 17, 18 and 19are schematic diagrams of an optical sensor assembly500according to another embodiment of the present disclosure. The optical sensor assembly500includes a circuit board510(e.g., a printed circuit board or a flexible circuit board), an optical sensor520, a connector540, a front cover530, and a back cover550.FIG. 17is a side view of the circuit board510, the optical sensor520, the connector540, the front cover530, and the back cover550.FIG. 18is a rear view of the circuit board510, the connector540, the front cover530, and the back cover550.FIG. 19is a front view of the front cover530.

In one non-limiting embodiment, when the circuit board510is fixed or sealed well with the front cover530to prevent dust and water from contacting the optical sensor520, the back cover550is not implemented.

The optical sensor520is attached to a front surface581of the circuit board510, and the optical sensor520is electrically connected with the circuit board510. The front cover530includes a receiving cavity560used to receive at least the optical sensor520. In one non-limiting embodiment, the receiving cavity560receives both the circuit board510and the optical sensor520. The front cover530further includes an optical element531used to allow incident light of a predetermined wavelength to transmit through the optical element531and condense the incident light onto the optical sensor520. The optical element531is a convex lens or a Fresnel lens.

In one embodiment, an outer surface583of the optical element531is a plane surface, and the convex lens or the Fresnel lens is formed at an inner surface584of the optical element531.

However, the present disclosure is not limited thereto. In one non-limiting aspect, the optical element531is a transparent layer used to guide incident light to the optical sensor520without condensing or diverging the incident light.

In one embodiment, the optical sensor520is a far infra-red thermal sensor used to detect a temperature of a thermal source. The aforementioned predetermined wavelength of the incident light is in a range from 8 micrometers to 12 micrometers, and the optical element531is used to allow the incident light to transmit through the optical element531with a transmittance in a range from 20% to 80%.

In another embodiment, the optical sensor520is an ambient light sensor. The aforementioned predetermined wavelength of the incident light is in a range from 390 nanometers to 700 nanometers.

The front cover530further includes a curved sheet533, a planar frame535connected to and surrounding the curved sheet533, and a wall structure570positioned on the curved sheet533. In another embodiment, the wall structure570is connected to the planar frame535. The receiving cavity560is positioned in and formed by the wall structure570. The optical element531is a part of the curved sheet533. In one embodiment, the curved sheet533has a plane surface within a region of the optical element531, and the rest part of the curved sheet533has a curved surface.

The optical sensor520is aligned with the optical element531. Preferably, the optical element531is parallel to a sensing surface585of the optical sensor520. In one aspect, the whole curved sheet533is transparent to the incident light. In another aspect, the curved sheet533is transparent to the incident light only within a region of the optical element531, and the rest part of the curved sheet533is opaque or semi-opaque to the incident light.

In one embodiment, the optical element531and the optical sensor520are neither parallel nor perpendicular to the planar frame535, as shown inFIG. 17. The angle difference between the planar frame535and the optical element531is determined based on design requirements of the optical sensor assembly500.

In another embodiment, the optical element531and the optical sensor520are parallel to the planar frame535. The optical element531is a part of the curved sheet533. The circuit board510is attached to the wall structure570. The shapes of the curved sheet533and the wall structure570are arranged such that the optical element531, the optical sensor520, and the circuit board510(determined by a tile angle of the outer loop wall572) are all parallel. When the tile angle is changed, a light receiving angle of the optical element531and optical sensor520is also altered.

The wall structure570includes an inner loop wall571surrounding the optical element531and an outer loop wall572surrounding the inner loop wall571. The inner loop wall571and the outer loop wall572have different heights at different edges of the front cover530, e.g., lower at an upper edge and higher at a lower edge to cause the optical sensor520to have an angle difference with respect to the planar frame535.

One end of the inner loop wall571is connected to the curved sheet533and another end of the inner loop wall571has an opening576. One end of the outer loop wall572is connected to the curved sheet533and another end of the outer loop wall572has an opening577. The area of the circuit board510is between the area of the opening576of the inner loop wall571and the area of the opening577of the outer loop wall572. In other words, the area of the circuit board510is larger than the area of the opening576of the inner loop wall571, and the area of the circuit board510is smaller than the area of the opening577of the outer loop wall572so as to be accommodated in the outer loop wall572.

The receiving cavity560includes a first cavity561for receiving the optical sensor520and a second cavity562for receiving the circuit board510. The first cavity561is positioned in the inner loop wall571. The second cavity562is positioned in the outer loop wall572.

To enhance the mechanical strength, the wall structure570further includes a plurality of ridge walls573connecting the inner loop wall571, the outer loop wall572and the curved sheet533. Each of the ridge walls573has an indent574on an edge575of that ridge wall573connecting the inner loop wall571and the outer loop wall572. The second cavity562is formed by the indents574of all of the ridge walls573.

In one non-limiting embodiment, the indents574and the second cavity562are not implemented. In this case, the circuit board510is attached to the inner loop wall571and the ridge walls573to seal the first cavity561.

In one non-limiting embodiment, the ridge walls573are not implemented. In this case, the opening577of the outer loop wall572defines the second cavity562.

In one non-limiting embodiment, the inner loop wall571is not implemented. In another one non-limiting embodiment, the outer loop wall572is not implemented. In another one non-limiting embodiment, both of the inner loop wall571and the outer loop wall572are not implemented.

According toFIG. 18, there are spaces between the ridge walls573, the inner loop wall571and the outer loop wall572. However, the present disclosure is not limited thereto. In one non-limiting embodiment, the ridge walls573fill all the spaces between the inner loop wall571and the outer loop wall572so that the wall structure570is a thick and solid loop wall surrounding the optical element531and the first cavity561.

In one embodiment, the front cover530, including the optical element531, is made of polypropylene or polyethylene. The front cover530, including the optical element531and the wall structure570, is produced via injection molding as a single piece. However, the present disclosure is not limited thereto. In one non-limiting aspect, the optical element531is formed separately and has different materials from the front cover530, and then combined with the front cover530.

In another embodiment, the optical element531includes at least one of a polypropylene film, a polyethylene film, a silicon film, a germanium film, and a diamond-like carbon film.

The connector540is attached to a back surface582of the circuit board510, and the connector540is electrically connected to the circuit board510. The connector540is used to transmit electrical signals to and from the optical sensor520. In addition, the connector540is used to transmit electrical signals between the optical sensor520and an external electronic device that adopts the optical sensor assembly500. The back cover550is attached to the outer loop wall572, for example, via a water-proof and dust-proof adhesive. The back cover550is used to seal the opening577of the outer loop wall572. The back cover550has an opening555used to expose an end545of the connector540.

The optical sensor520generates electrical signals by detecting the incident light penetrating the optical element531. The connector540transmits the electrical signals to a processor of an electronic device for predetermined control.

In one embodiment, the circuit board510is attached to the inner loop wall571and the ridge walls573, for example, via a water-proof and dust-proof adhesive. In this way, the circuit board510, the inner loop wall571, the curved sheet533, and the optical element531form a sealed enclosure for accommodating and protecting the optical sensor520from various hazards of the ambient environment, such as water, dust, electrical damage and mechanical damage. The outer loop wall572and the back cover550provide additional protection for the optical sensor520against the hazards of the ambient environment.

In one embodiment, the optical sensor assembly500is applied to an electronic device. The front cover530further includes at least one latching hook532configured for attaching the optical sensor assembly500to the other parts of the electronic device. In the embodiment shown inFIGS. 17, 18 and 19, the front cover530includes two latching hooks532. In another embodiment, the front cover530includes more or less latching hooks532.

In one non-limiting embodiment, the optical sensor assembly500is attached to the electronic device by other means such as screws or adhesive, and the at least one latching hook532is not implemented.

It should be mentioned that although the front cover530is shown to have a rectangular appearance, it is only to illustrate but not to limit the present disclosure. In other embodiments, the front cover530has other shapes such as a circular or ellipse shape according to a receiving opening of the electronic device adopting the optical sensor assembly500.

In the present disclosure, the type of the connector330and540is not particularly limited as long as it is combinable to another connector of an electronic device that adopts the optical sensor assembly300and500.

As mentioned above, in an auto detection system, using an image sensor has a privacy concern and using a PIR motion sensor is unable to detect a steady object. Therefore, the present disclosure further provides an auto detection system using a thermopile sensor (FIG. 4) and operating methods thereof (FIGS. 8 and 10) that have broad applications such as the human detection in an elevator, the urine-wet detection, the stove detection, the hair temperature detection and the skin temperature detection.