CN110645607B

CN110645607B - Range hood with thermal image detection function and control method thereof

Info

Publication number: CN110645607B
Application number: CN201811401689.3A
Authority: CN
Inventors: 陈瑞昌; 张志任; 刘崇猷
Original assignee: Taiwan Sakura Corp
Current assignee: Taiwan Sakura Corp
Priority date: 2018-06-27
Filing date: 2018-11-22
Publication date: 2021-01-05
Anticipated expiration: 2038-11-22
Also published as: CN110645607A; CN209484687U; TW202001156A; TWI673458B

Abstract

A range hood with thermal image detection function and a control method thereof. The range hood is suitable for detecting the thermal image distribution of the heating device. The range hood includes a thermal image detection circuit, a control circuit and an exhaust circuit. The thermal image detection circuit can obtain the temperature plane distribution data of the heating device. The control circuit obtains a first detection result of the thermal image detection circuit in a first sampling period, and starts the exhaust circuit to operate when the first detection result meets a slow start condition. And the control circuit obtains a second detection result of the thermal image detection circuit in a second sampling period, and starts the exhaust circuit to operate when the second detection result meets a quick start condition, wherein the second sampling period is less than the first sampling period. Therefore, the invention can automatically start the exhaust operation of the range hood according to the thermal image detection result.

Description

Range hood with thermal image detection function and control method thereof

Technical Field

The present invention relates to an exhaust device, and more particularly, to a range hood with thermal image detection function and a control method thereof.

Background

The range hood is common household electrical appliance in the existing kitchen. The main working side of the oil smoke exhauster is to discharge the oil smoke generated in the cooking process out of the room through the rotation of the fan. Generally, a range hood is provided with a plurality of buttons with different fan rotation speeds for users to press to start operation according to requirements. However, this manual activation method requires the cooking device to be released while the person is cooking, so that the cooking device can be manually activated by pressing the button. Similarly, when cooking is completed, the hood must be turned off again by manually pressing the button.

Disclosure of Invention

The embodiment of the invention provides a range hood with a thermal image detection function and a control method thereof, which can enable the range hood to relatively automatically execute intelligent operation control according to a thermal image detection result.

The embodiment of the invention provides a range hood with a thermal image detection function, which is suitable for detecting the thermal image distribution of a heating device. The range hood includes a thermal image detection circuit, a control circuit and an exhaust circuit. The thermal image detection circuit is provided with a plurality of thermal image detectors to obtain temperature plane distribution data of the heating device, wherein the temperature plane distribution data comprises a plurality of temperature detection values, and any temperature detection value is the temperature detection result of the image detector. The control circuit is electrically connected with the thermal image detection circuit and the exhaust circuit. The control circuit obtains a first detection result of the thermal image detection circuit in a first sampling period, and starts the exhaust circuit to operate when the first detection result meets a slow start condition. And the control circuit obtains a second detection result of the thermal image detection circuit in a second sampling period, and starts the exhaust circuit to operate when the second detection result meets a quick start condition, wherein the second sampling period is less than the first sampling period.

The embodiment of the invention provides a control method of a range hood, which is suitable for detecting thermal image distribution of a heating device, the range hood is provided with a thermal image detection circuit, the thermal image detection circuit is provided with a plurality of thermal image detectors to obtain temperature plane distribution data of the heating device, wherein the temperature plane distribution data comprises multipoint temperature detection values, and any temperature detection value is a temperature detection result of the image detectors. And obtaining a second detection result of the thermal image detection circuit in a second sampling period, and starting the exhaust circuit to operate when the second detection result meets a quick start condition, wherein the second sampling period is less than the first sampling period.

In summary, the range hood with thermal image detection function and the control method thereof provided by the embodiments of the present invention can relatively determine slow start or fast start of the exhaust operation according to different usage conditions of the cooking heat source through thermal image detection, so that not only manpower operation can be reduced, but also automatic start operation can be accurately provided.

For a better understanding of the nature and technical content of the present invention, reference should be made to the following detailed description of the invention and the accompanying drawings, which are provided for illustration purposes only and are not intended to limit the scope of the invention.

Drawings

Fig. 1 is a schematic view of a range hood with thermal image detection provided in an embodiment of the present invention.

Fig. 2 is a distribution diagram of a thermal image detection circuit according to an embodiment of the invention.

FIG. 3A is a schematic view of a thermal image frame according to an embodiment of the invention.

FIG. 3B is a schematic view of a thermal image frame according to an embodiment of the invention.

Fig. 4 is a control flow chart of the range hood according to the embodiment of the present invention.

Fig. 5 is a flow chart of slow start operation of the range hood according to the embodiment of the present invention.

Fig. 6 is a flow chart of the quick start operation of the range hood according to the embodiment of the present invention.

Fig. 7 is a flow chart of the high temperature protection operation of the range hood according to the embodiment of the present invention.

Fig. 8 is a flow chart of the automatic closing operation of the range hood according to the embodiment of the present invention.

Detailed Description

The embodiment of the invention provides a range hood with a thermal image detection function and a control method thereof. Specifically, the heating device and the range hood in the kitchen equipment are usually used together, however, the range hood of the embodiment can generate active and large-area heat source change detection for various cooking behaviors in the heating device by integrating the temperature detection function of thermal induction besides the basic function operation of discharging the oil fume, and the operation of the range hood is relatively automatically started or closed according to the detection result, so that the inconvenience of manual operation of the range hood is effectively reduced, the temperature change of various heat sources of the heating device in the cooking process can be more accurately judged, and the range hood can provide various intelligent controls accordingly. The heating device may be a gas oven, an induction cooker, or other various cooking devices for cooking, and the following explanation will be made on the gas oven for convenience.

[ example of a Range hood having thermal image detection function ]

Referring to fig. 1, fig. 1 is a schematic view of a range hood with thermal image detection function according to an embodiment of the present invention. The range hood 1 with the thermal image detection function of the present embodiment can provide a friendly operation of intelligent control by wide-area detection of the heat source temperature. In one embodiment, the range hood 1 may include a thermal image detection circuit 10, a control circuit 12, and an exhaust circuit 14. The thermal image detection circuit 10 is electrically connected to the control circuit 12, and the control circuit 12 is electrically connected to the exhaust circuit 14. The thermal image detection circuit 10 can detect the temperature of the heat source generated by the gas stove, and the temperature detection range can cover the range of the heating region provided by the gas stove. In an embodiment, the thermal image detection circuit 10 has a plurality of thermal image detectors 101, and the thermal image detectors 101 are disposed above the gas stove in a planar arrangement as shown in fig. 2, for example, so that various heat source temperature changes of each heating area can be effectively detected by the wide-area arrangement. However, the number and distribution of the thermal image detectors 101 in the present invention are not limited thereto, and the present invention may be applied as long as the change in the heating temperature of the gas furnace can be detected smoothly. The thermal image detector 101 may be, for example, a thermal image capable of converting the intensity of thermal radiation emitted from the surface of the object to be detected into a thermal image with a relatively different temperature distribution, and in an embodiment, the thermal image detector 101 may be an infrared thermal image detector, but the invention is not limited thereto.

The control circuit 12 can provide relatively intelligent human-based operation control according to the detection result of the thermal image detection circuit 10. In one embodiment, the control circuit 12 can further determine the usage status of the gas stove, such as whether the gas stove is cooking or the amount of fire power used during cooking, based on the detection result of the thermal image detection circuit 10. When the control circuit 10 knows the usage of the gas stove, it can control the range hood 1 to automatically start or stop operation. In one embodiment, when the control circuit 12 knows to start cooking, it can output a driving signal to the exhaust circuit 14 to start the operation of the exhaust circuit 14. In one embodiment, when the control circuit 12 knows that the high temperature continues to rise during cooking and is harmful to the pot, the control circuit 12 can also warn the relevant person or wirelessly control the gas stove to be turned off. In one embodiment, when the control circuit 12 knows that cooking is finished, it can output a driving signal to the exhaust circuit 14 to stop the operation of the exhaust circuit 14.

The exhaust circuit 14 may include, for example, a drive circuit 141 and a fan circuit 143. The driving circuit 141 is electrically connected to the fan circuit 143, and controls the fan circuit 143 according to a driving signal output by the control circuit 12. In one embodiment, when the driving circuit 141 receives the driving signal representing the activation, the fan circuit 143 is controlled to activate, so as to enable the range hood 1 to start exhausting smoke. When the driving circuit 141 receives the driving signal representing stopping, the fan circuit 143 is controlled to stop operation, so that the range hood 1 is turned off to stop exhausting. It should be noted that the control circuit 12 may further provide driving signals with different rotation speeds to control the fan circuit 143 to operate at different motor rotation speeds through the driving circuit 141.

It should be noted that in an embodiment, the control circuit 12 reads a plurality of temperature plane distribution data of the detection result of the thermal image detection circuit 10 through a plurality of sampling cycles, and performs statistical and analytical correlation calculation on the plurality of temperature plane distribution data, so as to obtain various dynamic and static cooking behavior modes of the gas stove at present. For example, in a single sampling period, the control circuit 12 obtains all the detection results of all the thermal image detectors 101 at the same time, that is, each thermal image detector 101 outputs a temperature detection value, and the temperature detection value reflects the temperature variation of the heat source image at the corresponding detection position of the thermal image detector 101. For example, the temperature plane distribution data formed by all the outputs of the thermal image detector 101 for the thermal image detection circuit 10 can be as shown in fig. 3A and 3B. For the thermal image in fig. 3A, the hot spot 301 represents the detection result of a certain thermal image detector 101, and the color shade of the hot spot 301 or the size of the hot spot may vary with the temperature of the heat source. As can be seen by comparing fig. 3A and 3B, the distribution area and density of the hot spot 301 in fig. 3B are more obvious than those in fig. 3A. Therefore, it can be known to the control circuit 12 that the gas stove is cooking by analyzing and calculating the data related to the thermal images in FIG. 3A and FIG. 3B, and the temperature is increased with the cooking time, for example, from FIG. 3A to FIG. 3B.

In an embodiment, the control circuit 12 may further include a slow start circuit 121, a fast start circuit 123, a high temperature protection circuit 125, and an auto-close circuit 127. The slow start circuit 121 and the fast start circuit 123 are used to determine when to start the operation of the exhaust circuit 14. The slow start circuit 121 may detect the use condition of cooking with slow fire in a gas stove, for example. The quick start circuit 123 may detect the use of gas stove cooking on a big fire, for example. The high temperature protection circuit 125 is used to determine whether the cooker on the gas stove is heated after the exhaust circuit 14 is started, and determine whether to output the prompt message according to the determination result. The automatic shutdown circuit 127 determines whether the cooking on the gas stove should be stopped after the exhaust circuit 14 is started, and determines whether to control the exhaust circuit 14 to stop operating according to the determination result. The determination processing method of each circuit in the control circuit 12 is only an example, and the present invention is not limited thereto.

In this embodiment, the slow start circuit 121 obtains the first detection result of the thermal image detection circuit 10 in the first sampling period, and when the first detection result meets the slow start condition, the slow start circuit 121 starts the exhaust circuit 14 to operate. For example, the first sampling period includes a plurality of sampling periods, so that the first detection result may have a plurality of sampling data of temperature profile data, and the slow start condition is, for example, a default heat source density driving variation corresponding to the gas stove set for cooking with small fire. Therefore, after the slow start circuit 121 performs the statistics and analysis calculation on the first detection result, if the first detection result matches the default heat source density driving force variation, the slow start circuit 121 may control the exhaust circuit 141 to start operation.

The fast start circuit 123 obtains a second detection result of the thermal image detection circuit 10 in a second sampling period, and when the second detection result meets a fast start condition, the fast start circuit 123 starts the operation of the exhaust circuit 14. For example, the second sampling period is a single sampling period, so the second detection result is a sampling data of a single piece of temperature plane distribution data, and the fast start condition is a preset high temperature start value, for example. Therefore, when the quick start circuit 123 determines that the high temperature average value of the temperature detection values with the highest temperature at the front M points in the temperature plane distribution data in the second detection result is greater than the preset high temperature start value, the quick start circuit 123 may control the exhaust circuit 14 to start operation. Since the fast start circuit 123 only needs to determine that a single sampling data of a single sampling period is much smaller than a plurality of sampling data of a plurality of sampling periods that the slow start circuit 121 needs to determine, the determination time required by the fast start circuit 123 to start the exhaust circuit 14 is much shorter than that of the slow start circuit 121, so that the fast start circuit has a fast start effect.

The high temperature protection circuit 125 outputs a prompt message when the detection result of the thermal image detection circuit 10 meets a high temperature protection condition after the exhaust circuit 14 is started, so that a person or a gas stove can stop heating operation according to the prompt message. For example, the high temperature compliance condition is that a high temperature average value of the temperature detection values with the highest temperature at the first N points in the temperature plane distribution data complies with an abnormal high temperature value, or that a slope formed by each of the highest temperature values in a plurality of continuous temperature plane distribution data complies with a predetermined rising slope value.

The auto-shut down circuit 127 controls the exhaust circuit 14 to operate at a slow speed for a predetermined time and shut down or shut down directly after the exhaust circuit 14 is started and when the detection result of the thermal image detection circuit 10 meets a shut-down condition, which is not limited in the present invention. For example, the shutdown condition is that a slope formed between each of the highest temperature values in the plurality of consecutive temperature plane distribution data conforms to a predetermined descending slope value.

[ operation example of Range hood with thermal image detection function ]

Referring to fig. 4 in conjunction with fig. 1, fig. 4 is a flow chart illustrating the operation of the range hood according to the embodiment of the present invention. The operation method of the range hood 1 described in this embodiment can be performed manually or automatically according to the setting conditions, but the invention is not limited thereto. The flow shown in fig. 4 may perform the following steps, for example, in conjunction with the architecture of fig. 1.

In step S401, the range hood 1 starts the thermal image detection function. Specifically, when the range hood 1 is powered on, the thermal image detection circuit 10 can obtain the operating power to start the temperature detection, but the exhaust circuit 14 is not started to operate.

In step S403, the range hood 1 performs slow start detection. In step S403, the control circuit 12 determines whether the slow start condition is satisfied according to the detection result of the thermal image detection circuit 10, and then determines to start the operation of the exhaust circuit 14. The specific determination manner of step S403 will be described in detail later.

In step S405, the range hood 1 performs a quick start detection. In this step S405, the control circuit 12 determines whether the fast start condition is satisfied according to the detection result of the thermal image detection circuit 10, and then determines to start the operation of the exhaust circuit 14. The specific determination manner of step S405 will be described in detail later.

In step S407, it is determined whether the exhaust circuit 14 is activated. Whether the exhaust circuit 14 is started or not can be known according to the judgment result of one of the steps S403 or S405, and it is sufficient that one of the steps S403 or S405 judges that the exhaust circuit 14 is started or not. If the determination in step S407 is no, step S403 and step S405 are repeatedly executed. The execution of steps S403 and S405 is not limited to a sequential execution order, and may be performed simultaneously, for example.

In step S409, after the exhaust circuit 14 is activated, the high temperature detection is further activated. In this step S409, the control circuit 12 determines whether the high temperature protection condition is satisfied according to the detection result of the thermal image detection circuit 10, and then determines whether to perform a subsequent procedure of high temperature protection. The specific determination manner of step S409 will be described in detail later.

In step S411, auto-off detection is initiated. In step S411, the control circuit 12 determines whether the shutdown condition is satisfied according to the detection result of the thermal image detection circuit 10, and then determines whether to perform a subsequent procedure of shutting down the exhaust circuit 14. The specific determination method of S411 will be described in detail later.

In step S413, it is determined whether to turn off the exhaust circuit 14. The step S413 can know whether to shut down the operation of the exhaust circuit 14 according to the execution result of the step S411, and if not, the step S413 returns to the step S409 to continue the execution. And stops when the judgment in the judgment step S413 is yes.

In step S415, the exhaust operation is stopped, and in step S415, when the control circuit 12 is determined to be turned off according to the detection result of the thermal image detection circuit 10, the control circuit 12 controls the exhaust circuit 14 in the start operation to stop the operation.

[ operation example of Slow Start detection ]

Referring to fig. 5 in conjunction with fig. 1, fig. 5 is a flowchart illustrating a slow start operation of a range hood according to an embodiment of the present invention. The slow start operation of the range hood 1 described in this embodiment is further described with reference to S403 in fig. 4, but the invention is not limited thereto. The flow shown in fig. 5 may perform the following steps, for example, in conjunction with the architecture of fig. 1.

In step S501, the thermal image array data is read. Specifically, the thermal image detection circuit 10 reads a piece of temperature plane distribution data according to the control of the control circuit 12, and the piece of temperature plane distribution data may be similar to the thermal image distribution shown in fig. 3A or fig. 3B.

In step S503, the temperature distribution amount is calculated. In this step S503, the control circuit 12 calculates the distribution condition of each temperature from the first detection result of the piece of temperature plane distribution data according to the execution result of the step S501. For example, in step S503, the number of hot spots at each temperature in the temperature plane distribution data is counted and the number of hot spots with the same temperature is accumulated.

In step S505, offset monitoring is performed. In step S505, the control circuit 12 can track the accumulated number of hot spots at a certain temperature by offset monitoring according to the calculation result in step S503, for example, can track the peak value with the largest accumulated number of hot spots.

In step S507, it is determined whether the monitored data is sufficient. In step S507, it is determined whether the number of pieces of temperature plane distribution data read in step S501 matches the number set in the first sampling period, for example, the first sampling period may be set to read 10 pieces of temperature plane distribution data.

In step S509, data analysis is performed. In step S509, the peak value with the largest accumulated number of hot spots in each piece of temperature plane distribution data in the first sampling period is tracked and analyzed, so as to obtain the heat source density driving variation.

In step S511, it is determined whether the slow start condition is satisfied. In step S511, the density trend obtained in step S509 is compared with a slow start condition, such as a default heat source density trend change corresponding to a gas stove cooking with slow fire, but the invention is not limited thereto.

In step S513, the control circuit 12 starts the operation of the exhaust circuit 14. In step S513, when the density trend comparison obtained in step S509 matches the slow start condition, the operation of the exhaust circuit 14 is automatically started. If the comparison result of S511 is not matched, the process returns to step S501 to continue.

[ operating example for quick Start detection ]

Referring to fig. 6 in conjunction with fig. 1, fig. 6 is a flow chart illustrating a quick start operation of a range hood according to an embodiment of the present invention. The fast start operation of the range hood 1 described in this embodiment is further described with reference to S405 in fig. 4, but the invention is not limited thereto. The flow shown in fig. 6 may perform the following steps, for example, in conjunction with the architecture of fig. 1.

In step S601, the thermal image array data is read. Specifically, the thermal image detection circuit 10 reads a piece of temperature plane distribution data according to the control of the control circuit 12, and the piece of temperature plane distribution data may be similar to the thermal image distribution shown in fig. 3A or fig. 3B.

In step S603, the data with the highest temperature at the M points before the reading is performed. In this step S603, the control circuit 12 performs data reading on the top M-point temperature highest data of this piece of temperature plane distribution data according to the execution result of step S601. For example, the value of M is 5 points, but the invention is not limited thereto.

In step S605, a high temperature average value is calculated. In step S605, the control circuit 12 calculates an average value of the M-point temperature values read in step S603, and obtains a high-temperature average value.

In step S607, it is determined whether the high temperature start condition is satisfied. The high temperature start condition in step S607 is, for example, a preset high temperature start value, and is determined to be satisfied when the high temperature average value is greater than or equal to the preset high temperature start value, otherwise, is not satisfied.

In step S609, the control circuit 12 starts the operation of the exhaust circuit 14. In step S609, the operation of the exhaust circuit 14 is automatically started when it is determined in step S607 that the high temperature start condition is satisfied. If the determination result of the SS607 is not met, the process returns to step S601 to continue.

[ working example of high temperature protection test ]

Referring to fig. 7 in conjunction with fig. 1, fig. 7 is a flow chart of the high temperature protection operation of the range hood according to the embodiment of the present invention. The high temperature protection operation of the range hood 1 described in this embodiment is further described with reference to step S409 in fig. 4, but the invention is not limited thereto. The flow shown in fig. 7 may perform the following steps, for example, in conjunction with the architecture of fig. 1.

In step S701, the thermal image array data is read. Specifically, the thermal image detection circuit 10 reads a piece of temperature plane distribution data according to the control of the control circuit 12, and the piece of temperature plane distribution data may be similar to the thermal image distribution shown in fig. 3A or fig. 3B.

In step S703, a climbing slope is detected. In step S703, the control circuit 12 obtains the highest temperature value of each point of the plurality of pieces of temperature plane distribution data according to the execution result of step S701, and determines and compares the obtained highest temperature values with the high temperature protection condition. The high temperature protection condition is, for example, a predetermined slope change or a value greater than a predetermined rising slope. That is, when the slope formed by the connection among the obtained maximum temperature values is consistent with the change of the preset slope or is larger than the preset rising slope value, the high temperature abnormality can be determined.

In step S705, a quick determination check is performed. The execution manner in step S705 is similar to the operation manner in fig. 6, and only the fast-meeting condition in step S607 is changed to the high-temperature protection condition, which may be, for example, an abnormal high-temperature value, and the abnormal high-temperature value is greater than the preset high-temperature start value. Therefore, when the high temperature average value is greater than or equal to the abnormal high temperature value, it is determined that the high temperature abnormality occurs.

In step S707, it is determined whether the high temperature is abnormal. In step S707, if a high-temperature abnormality occurs according to any of the execution results of step S703 or step S705, the control circuit 12 directly determines that the high-temperature abnormality occurs.

In step S709, a prompt message is output. In step S709, when it is determined in step S707 that the high temperature abnormality is satisfied, the control circuit 12 outputs a prompt message. In one embodiment, the gas stove may further include a prompt circuit electrically connected to the control circuit, wherein the prompt circuit is configured to output an audio signal or display a prompt message related to the audio signal to inform a relevant person of abnormal high temperature during the cooking process. In addition, in an embodiment, the control circuit 12 can further wirelessly output the prompt message to the gas stove, so that the gas stove can stop the heating operation of the gas stove after wirelessly receiving the prompt message, thereby preventing the abnormal high temperature from continuously rising.

[ operating example for automatic closing ]

Referring to fig. 8 in conjunction with fig. 1, fig. 8 is a flow chart illustrating an automatic closing operation of a range hood according to an embodiment of the present invention. The automatic closing operation of the range hood 1 described in this embodiment is further described with reference to S411 in fig. 4, but the invention is not limited thereto. The flow shown in fig. 8 may perform the following steps, for example, in conjunction with the architecture of fig. 1.

In step S801, the thermal image array data is read. Specifically, the thermal image detection circuit 10 reads one or more pieces of temperature plane distribution data according to the control of the control circuit 12, and the piece of temperature plane distribution data may be similar to the thermal image distribution shown in fig. 3A or fig. 3B.

In step S803, a falling slope is detected. In step S803, the control circuit 12 obtains the highest temperature value of each point of the plurality of pieces of temperature plane distribution data according to the execution result of step S801, and compares the obtained highest temperature values with a shutdown condition, such as a predetermined slope change or a predetermined falling slope value. That is, when the slope of the connection between the obtained maximum temperature values is consistent with the predetermined slope variation or is smaller than the predetermined descending slope value, it is determined that the shutdown phenomenon occurs.

In step S805, it is determined whether to turn off. In step S805, the control circuit 12 can know whether or not the shutdown is performed based on the execution result of step S803. If yes in step S805, step S807 is executed, and if no in step S805, step S801 is executed.

In step S807, the rotation speed is reduced. When the control circuit 12 is turned off in step S807 according to the determination of step S805, the control circuit 12 controls the exhaust circuit 14 in operation to reduce the rotation speed and operate for a predetermined time.

In step S809, it is determined whether the predetermined time has expired. If the determination in step S809 is yes, step S811 is executed, and if the determination in step S809 is not yes, step S809 continues to be executed.

In step S811, the operation is stopped. In step S811, the control circuit 12 controls the exhaust circuit 14 to stop operation, so that the range hood enters a closed state where exhaust is stopped.

In another embodiment, when the determination in step S805 is yes, the control circuit 12 may also directly control the exhaust circuit 14 to stop operating.

[ efficacy of example ]

In summary, the range hood with thermal image detection function and the control method thereof provided by the embodiments of the present invention can automatically start or automatically close the exhaust related operation according to the result of thermal image detection without human intervention. And also provides overheat detection in the cooking process, thus effectively protecting the cooker from being damaged due to high temperature.

The above description is only an example of the present invention, and is not intended to limit the scope of the present invention.

Claims

1. A range hood with thermal image detection function is characterized in that the range hood is suitable for detecting the thermal image distribution of a heating device and comprises:

a thermal image detection circuit having a plurality of thermal image detectors for obtaining a temperature plane distribution data of the heating device, wherein the temperature plane distribution data includes a plurality of temperature detection values, and any one of the temperature detection values is a temperature detection result of the image detector;

an exhaust circuit; and

a control circuit electrically connected to the thermal image detection circuit and the exhaust circuit;

the control circuit obtains a first detection result of the thermal image detection circuit in a first sampling period, and starts the exhaust circuit to operate when the first detection result meets a slow start condition;

the control circuit obtains a second detection result of the thermal image detection circuit in a second sampling period, and starts the exhaust circuit to operate when the second detection result meets a quick start condition;

wherein the second sampling period is less than the first sampling period.

2. The range hood according to claim 1, wherein the first detection result is a trend change of heat source density corresponding to a plurality of temperature plane distribution data, the slow start condition is a default trend change of heat source density corresponding to the heating device cooking with small fire, the second detection result is a high temperature average value of temperature detection values having the highest temperatures of the first several points of the multi-point temperature detection values in the temperature plane distribution data, and the fast start condition is a preset high temperature start value.

3. The range hood as set forth in claim 1, wherein the control circuit outputs a prompt message when the control circuit meets a high temperature protection condition according to the detection result of the thermal image detection circuit after the exhaust circuit is started, so that the heating device can stop heating operation according to the prompt message.

4. The range hood according to claim 3, wherein the high temperature protection condition is that a high temperature average value of temperature detection values having the highest temperatures at the first points of the multi-point temperature detection values in the temperature plane distribution data conforms to an abnormal high temperature value, and the high temperature protection condition is that a slope formed between each of the highest temperature values in a plurality of consecutive temperature plane distribution data conforms to a predetermined rising slope value.

5. The range hood as set forth in claim 3, wherein the control circuit controls the exhaust circuit to operate at a slow speed for a predetermined time and then to be turned off when the control circuit conforms to a turn-off condition according to the detection result of the thermal image detection circuit after the exhaust circuit is turned on, wherein the turn-off condition is that a slope formed between each of the highest temperature values in the plurality of continuous temperature plane distribution data conforms to a predetermined falling slope value.

6. A control method of a smoke exhaust ventilator is characterized in that the control method is suitable for detecting thermal image distribution of a heating device, the smoke exhaust ventilator is provided with a thermal image detection circuit, the thermal image detection circuit is provided with a plurality of thermal image detectors to obtain temperature plane distribution data of the heating device, the temperature plane distribution data comprises multipoint temperature detection values, and any temperature detection value is a temperature detection result of the image detector, the method comprises the following steps:

obtaining a first detection result of the thermal image detection circuit in a first sampling period, and starting an exhaust circuit of the range hood to operate when the first detection result meets a slow starting condition; and

obtaining a second detection result of the thermal image detection circuit in a second sampling period, and starting the exhaust circuit to operate when the second detection result meets a quick start condition;

wherein the second sampling period is less than the first sampling period.

7. The control method of claim 6, further comprising:

the first detection result is the heat source density trend change corresponding to a plurality of temperature plane distribution data, the slow starting condition is the default heat source density trend change corresponding to the heating device cooking with small fire, the second detection result is a high-temperature average value of the temperature detection values with the highest temperature of the first points of the multi-point temperature detection values in the temperature plane distribution data, and the fast starting condition is a preset high-temperature starting value.

8. The control method as claimed in claim 6, wherein after the exhaust circuit is started, when the range hood meets a high temperature protection condition according to the detection result of the thermal image detection circuit, the range hood outputs a prompt message so that the heating device can stop heating operation according to the prompt message.

9. The control method according to claim 8, wherein the high temperature compliance condition is a high temperature average value of temperature detection values having highest temperatures at first points of the plurality of point temperature detection values in the temperature plane distribution data, a compliance with an abnormal high temperature value, and the high temperature compliance condition is a condition that a slope formed between each highest temperature value in a plurality of consecutive temperature plane distribution data conforms to a preset rising slope value.

10. The control method as claimed in claim 8, wherein a control circuit of the range hood is configured to control the exhaust circuit to operate at a slow speed for a predetermined time and then shut down when the control circuit satisfies a shut down condition according to a detection result of the thermal image detection circuit after the exhaust circuit is activated, wherein the shut down condition is that a slope formed between each of maximum temperature values in a plurality of consecutive temperature plane distribution data satisfies a predetermined descending slope value.