Thermal imaging camera

Abstract

The present invention relates to a thermal imaging camera, comprising a processor and a storage unit storing instructions executable by the processor, the thermal imaging camera comprising: a shutter controller for controlling the opening and closing of a shutter of the thermal imaging camera; a microphone for measuring a sound source during the period of controlling the opening and closing of the shutter of the thermal imaging camera; the storage unit storing a mapping table; and the control unit for judging whether an erroneous operation of the shutter has occurred by judging whether the measured sound source is consistent with an operating sound source of the shutter, and in the case of an erroneous operation, inferring a correction offset by referring to the mapping table, and correcting the captured thermal image by means of the inferred correction offset.

Description

Technical Field

[0001] The present invention relates to a thermal imaging camera, and more particularly to a device capable of more accurately detecting erroneous operation occurring in a shutter of a thermal imaging camera. Background Art

[0002] Generally, in order to calibrate the thermal imaging sensor in a thermal imaging camera regularly or at any time, the shutter needs to operate normally. If the shutter is not operated properly, the best thermal imaging image cannot be obtained. For example, if an erroneous operation occurs at the time when the sensor calibration is required, such as the shutter is in an open state, the correction offset value will be calculated incorrectly, so that the movement of the photographed object appears as a ghost. On the contrary, if the calibration is performed in the state where the shutter is closed, the correction offset value can be calculated normally, but if the shutter is not opened due to an erroneous operation, but continues to be closed, the image can only present a monochrome picture.

[0003] Regarding this problem, Korean Patent Publication No. 10-2021-0070907, which discloses a thermal imaging state monitoring sensor, uses a method of comparing the difference between the average response values ​​of two shutter images with a reference value to determine whether there is an erroneous operation. The determination of erroneous operation according to this prior art includes the following steps.

[0004] 1. Obtain a first average response value for a first shutter image captured by a thermal imaging image sensor in a thermal imaging camera.

[0005] 2. Obtain a second average response value for a second shutter image captured by the thermal imaging image sensor in the thermal imaging camera.

[0006] 3. Compare the first average response value and the second average response value.

[0007] 4. Confirm whether the difference in the response values ​​is greater than a predetermined value.

[0008] 5. If the value is large, it is considered a shutter error and displayed to the user.

[0009] According to this prior art, even after obtaining the first shutter image and the second shutter image, if an erroneous operation occurs in the shutter closed state and the shutter cannot be opened, since the difference between the average response value of the first shutter image and the average response value of the second shutter image is less than a predetermined value, there is a problem that it is no longer possible to automatically detect whether the shutter has been erroneously operated. In addition, when photographing a fixed object with a constant temperature, even if an erroneous operation occurs in which the shutter cannot be closed, since the difference between the average response value of the first shutter image and the average response value of the second shutter image is less than a predetermined value, there is also a problem that it is no longer possible to automatically detect whether the shutter has been erroneously operated.

[0010] Therefore, in order to determine whether the shutter is operating normally, it is necessary to move away from the method of simply seeking the difference in the average response value of the shutter image, and require a new solution that can more accurately detect the malfunction state of the shutter in the thermal imaging camera and notify the user. Summary of the invention

[0011] The technical problem to be achieved by the present invention is to provide a thermal imaging camera that can more accurately monitor the operating state of the shutter of the thermal imaging camera even without calculating the difference in average response values ​​of shutter images in order to calibrate the thermal imaging sensor in the thermal imaging camera periodically or at any time.

[0012] The technical problem to be achieved by the present invention is to provide a thermal imaging camera capable of detecting maloperation of the thermal imaging camera by utilizing the operating sound of a mechanical shutter in order to calibrate a thermal imaging sensor in the thermal imaging camera periodically or at any time.

[0013] In order to achieve the technical problem, a thermal imaging camera according to an embodiment of the present invention includes a processor and a storage unit storing instructions executable by the processor, the thermal imaging camera including: a shutter controller for controlling the opening and closing of the shutter of the thermal imaging camera; a microphone for measuring the sound source during the control of the opening and closing of the shutter of the thermal imaging camera; the storage unit for storing a mapping table; the control unit for determining whether an erroneous operation of the shutter has occurred by determining whether the measured sound source is consistent with an operating sound source of the shutter, and in the event of an erroneous operation, inferring a correction offset by referring to the mapping table, and correcting the captured thermal image by means of the inferred correction offset.

[0014] The mapping table may include data pairs that perform a one-to-one matching between the temperature measured by the temperature sensor and the correction offset.

[0015] If the specific temperature does not exist in the mapping table, the control unit may infer the correction offset for the specific temperature by interpolating data pairs of temperature and correction offset included in the mapping table.

[0016] The mapping table may be generated through a pre-calibration process and stored in the storage unit before the thermal imaging camera is shipped out of the factory.

[0017] The control unit may estimate the correction offset only when the temperature measured by the temperature sensor satisfies a temperature variation condition, wherein the temperature measured varies more than a reference value compared to a previous temperature.

[0018] The temperature variation condition may be checked at every predetermined period.

[0019] When the erroneous operation of the shutter does not occur, the control unit may calculate the correction offset through the opening and closing operation of the shutter, and store the calculated correction offset in a mapping table.

[0020] The control unit may calculate a correction offset in each predetermined correction cycle and store it in a mapping table, wherein the correction cycle is applied differently to a first interval from when the power of the thermal imaging camera is turned on to when the thermal imaging sensor is stabilized and to a second interval when the thermal imaging sensor reaches a stable state.

[0021] The correction period of the first interval may be shorter than the correction period of the second interval.

[0022] The erroneous operation of the shutter may refer to an error in which the shutter cannot be opened and fixed in a closed state. After resetting the thermal imaging camera, the control unit controls the shutter to remain open, and only refers to the mapping table to infer the correction offset when the temperature measured by the temperature sensor satisfies a temperature change condition, wherein the temperature change condition is a condition in which the measured temperature changes by more than a reference value compared to the existing temperature.

[0023] According to the present invention, there is an advantage that the operating sound of the mechanical shutter in the thermal imaging camera can be used to more accurately detect the erroneous operation of the shutter of the thermal imaging camera.

[0024] Furthermore, according to the present invention, there is also an advantage that it is possible to distinguish whether the erroneous operation of the shutter is an erroneous operation in the shutter open state or an erroneous operation in the shutter closed state, thereby taking different measures according to the respective states. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a block diagram showing the structure of a thermal imaging camera according to an embodiment of the present invention.

[0026] Figure 2 is a diagram illustrating a hardware structure of a computing device that implements a thermal imaging camera.

[0027] Figure 3 FIG. 4 is a flow chart schematically illustrating a process of detecting shutter misoperation by a thermal imaging camera according to an embodiment of the present invention.

[0028] Figure 4 is shown in more detail Figure 3 Flowchart of the process.

[0029] Figure 5 This is a graph comparing the center frequency and level of the sound source measured by a microphone with that of a reference sound source.

[0030] Figure 6The present invention is a flowchart showing an operation process of a thermal imaging camera that can temporarily cope with a misoperation of a mechanical shutter.

[0031] Figure 7 It is shown Figure 6 A flowchart of a situation in which a mapping table is pre-generated before a product leaves the factory.

[0032] Figure 8 Illustrated in Figure 6 The situation in which a mapping table is generated by a controller of a thermal imaging camera during operation.

[0033] Fig. 9 The present invention is a flowchart showing an operation process of a thermal imaging camera that can temporarily cope with a situation in which a mechanical shutter cannot be opened in a closed state but is fixed. DETAILED DESCRIPTION

[0034] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0035] Figure 1 1 is a block diagram showing the structure of a thermal imaging camera 100 according to an embodiment of the present invention. The thermal imaging camera 100 may include a control unit 110, a storage unit 115, a mechanical shutter 120, a shutter controller 125, a thermal imaging sensor 130, a microphone 140, a display device 150, a speaker 155, and a temperature sensor 160.

[0036] The control unit 110 (or processor 110) functions as a controller for controlling the operations of other components of the thermal imaging camera 100, and can generally be implemented as a central processing unit (CPU), a microprocessor, etc. In addition, the storage unit 115 (or internal memory 115) serves as a storage medium for storing results executed by the control unit 110 or storing data required for the operation of the control unit 110, and can be implemented as a volatile memory or a non-volatile memory.

[0037] The mechanical shutter 120 is a physical shutter composed of a single or multiple blades, and will inevitably generate a sound source when it is opened and closed. The opening and closing operation of the mechanical shutter 120 is implemented by a shutter controller 125. As is known to all, the shutter controller 125 can be implemented by a rotary motor, a linear motor, or a variety of actuators in other forms.

[0038] The thermal imaging sensor 130 has a function of detecting the thermal imaging input to the thermal imaging camera 100 and outputting it as data in the open state or the closed state of the mechanical shutter 120. As is well known, the thermal imaging sensor uses infrared rays (rather than visible light) to generate images. For example, the thermal imaging sensor 130 receives infrared energy and uses the data of the infrared energy to generate an image through a digital or analog image output function.

[0039] However, if the surrounding environment changes, which changes the temperature of the sensor, the thermal imaging sensor 130 needs to be calibrated to obtain the best imaging image. The change in the surrounding environment is detected by using the measurement values ​​of the temperature sensor integrated in the thermal imaging sensor, the temperature sensor for measuring the sensor temperature, the temperature sensor for measuring the shutter temperature, and the temperature sensor for measuring the temperature around the lens. At this time, in order to calibrate the thermal imaging sensor, the shutter 120 operated before the thermal imaging camera is used.

[0040] When calibrating the thermal imaging sensor 130, first, an image is captured with the shutter closed. In this way, the control unit 110 calculates a separate calibration offset value for each pixel constituting the thermal imaging sensor 130 based on the imaging value of the thermal imaging. After the calculation is completed, the shutter is opened again, and at this time, the previously obtained separate calibration offset can be reflected to obtain a clear thermal image.

[0041] The microphone 140 is a component that converts an external sound wave signal into an electrical signal, and receives an operation sound source input of the mechanical shutter 120 when the mechanical shutter 120 operates, that is, when the mechanical shutter 120 is to be switched to an open state and / or when the mechanical shutter 120 is to be switched to a closed state.

[0042] The display device 150 is a device that can provide pixels to the user, such as a liquid crystal display (LCD) or a light-emitting diode (LED), and can display an imaging reminder according to the control of the control unit 110. In addition, the speaker 155 is a device that converts an electrical signal into a sound wave generated by vibration, and can output a sound reminder according to the control of the control unit 110.

[0043] The operations performed by organically combining the above components will be described in detail below.

[0044] First, the control unit 110 controls the mechanical shutter 120 to close by means of a control signal to the shutter controller 125. As described above, when the mechanical shutter 120 is closed, the thermal imaging camera 100 uses the thermal imaging sensor 130 to capture thermal images.

[0045] Afterwards, the control unit 110 calculates the correction offset of the thermal pixels included in the thermal image. Specifically, the control unit 110 calculates a separate correction offset according to the pixels included in the captured thermal image. For example, the separate correction offset can be stored in the storage unit 115 in the form of a matrix according to the position of the pixel.

[0046] As described above, after calculating the correction offset, the control unit 110 controls the mechanical shutter 120 to open through the shutter controller 125, and then shoots the external thermal image for the second time through the thermal imaging sensor 130. At this time, the control unit 110 applies the correction offset in the thermal image taken for the second time, so as to obtain a clear thermal image. Specifically, the control unit 110 applies the separate correction offset according to the pixels included in the thermal image taken for the second time. In particular, it is necessary to apply the separate correction offset so that the position of the pixels included in the thermal image taken once corresponds to the position of the pixels included in the thermal image taken for the second time.

[0047] In the present invention, the mechanical shutter 120 generates an inherent sound source according to its inherent characteristics. This inherent sound source can be pre-acquired and pre-stored in the storage unit 115 for the mechanical shutter 120 as a reference sound source. More specifically, if the difference between the operation sound source when the shutter is opened and the operation sound source when the shutter is closed is actually enough to distinguish them from each other, the operation sound source when the shutter is opened and the operation sound source when the shutter is closed can be stored separately. However, this is not limited to this. If the operation sound source when opening or closing is actually not much different, it can also be stored as one operation sound source.

[0048] The microphone 140 is an element that measures the sound source at at least one of the time point when the mechanical shutter 120 is closed and the time point when it is opened. Preferably, the microphone 140 can measure the sound source within a predetermined time, including before and after the generation time point of the control signal for conversion to the open / closed state, and provide the measurement to the control unit 110. Since the operation of the shutter 120 is performed in the control unit 110 based on the input signal of various sensors or the sensor surrounding temperature information, the control unit 110 can determine the operation time point of the shutter and the input time point of the microphone 140.

[0049] The control unit 110 determines whether the sound source measured by the microphone 140 is consistent with the shutter operation sound source (i.e., the reference sound source) stored in the storage unit 115. At this time, the control unit 110 can prevent errors caused by the external environment by removing a common sound source corresponding to noise from the measured sound source.

[0050] Finally, if the measured sound source is inconsistent with the reference sound source or the shutter sound source is not generated, the control unit 110 outputs a reminder about the erroneous operation of the mechanical shutter 120. In particular, the control unit 110 may output the reminder as an image through the display device 150 or as a sound through the speaker 155. In addition, the control unit 110 may also output the reminder as a message to a user at a remote location through a network.

[0051] According to the judgment result, if the measured sound source is consistent with the reference sound source (if the shutter sound source is generated normally), the above process is repeated in the next calibration step of the thermal imaging sensor 130 and the shutter is sensed to determine whether there is any erroneous operation.

[0052] Furthermore, if the measured sound source is inconsistent with the shutter operation sound source, the control unit 110 distinguishes whether the mechanical shutter 120 is erroneously operated in the open state or erroneously operated in the closed state and gives a warning, or gives a warning without distinguishing whether an erroneous operation occurs.

[0053] If the mechanical shutter 130 is in an open state by mistake, the latest correction offset cannot be accurately calculated. Therefore, in this case, as a temporary measure, the control unit 110 can also perform correction for the thermal pixel by applying the correction offset before the mistake to the currently captured thermal image.

[0054] In addition, the temperature sensor 160 can detect the temperature of a specific location, and can be implemented by various components such as thermocouples, resistance temperature detectors (RTDs), thermistors, etc. The temperature sensor 160 can be disposed on the thermal imaging sensor 130 or near the mechanical shutter 120, or on both sides at the same time.

[0055] In addition, in order to cope with the situation where the mechanical shutter 120 may be misoperated in the future, the control unit 110 may pre-measure the correction offset with a predetermined correction cycle and store it in the form of a mapping table in the storage unit 115. Such a cycle may be different depending on whether the temperature detected by the temperature sensor 160 is stabilized (normal state). For example, when the power of the thermal imaging camera 100 is turned on, before the temperature of the temperature sensor 160 is stabilized, the correction offset may be measured with a short cycle (e.g., 20 seconds, 40 seconds, 1 minute, etc.), and after the temperature is stabilized, the correction offset may be measured with a longer cycle (e.g., 4 minutes and 30 seconds, 10 minutes, etc.).

[0056] The mapping table may store data pairs that match the relationship between temperature and correction offset in a one-to-one manner. Therefore, although the correction offset cannot be obtained for all temperature values, for temperatures between the currently measured temperature values, the control unit 110 can calculate the correction offset by using a variety of interpolation techniques. As such interpolation techniques, various known techniques such as linear interpolation, nearest interpolation, bi-cubic interpolation, and area interpolation can be used.

[0057] As described above, when the mechanical shutter 120 operates normally, such a mapping table can be generated by the correction offset measurement performed by the control unit 110, but is not limited thereto. Therefore, the mapping table can also be generated by a pre-calibration process before the thermal imaging camera 100 is shipped and stored in the storage unit 115.

[0058] Figure 2 is a diagram illustrating a hardware structure of a computing device 200 that implements the thermal imaging camera 100 .

[0059] The computing device 200 has a bus 220, a processor 230, an internal memory 240, a storage 250, an input / output interface 210, and a network interface 260. The bus 220 is a data transmission path for the processor 230, the internal memory 240, the storage 250, the input / output interface 210, and the network interface 260 to send and receive data to each other. However, the method of connecting the processor 230 and the like to each other is not limited to the method of connecting with the bus. The processor 230 is an operation processing device such as a central processing unit (CPU) or a graphics processing unit (GPU). The internal memory 240 is an internal memory such as a random access memory (RAM) or a read-only memory (ROM). The storage 250 is a storage device such as a hard disk, a solid state drive (SSD) or a memory storage card. In addition, the storage 250 can be an internal memory such as a random access memory (RAM) or a read-only memory (ROM).

[0060] The input / output interface 210 is an interface for connecting the computing device 200 and an input / output device. For example, a keyboard, a mouse, etc. are connected to the input / output interface 210 .

[0061] The network interface 260 is an interface for connecting the computing device 200 to an external device in a communicable manner to send and receive transmission data packets. The network interface 260 can be a network interface for connecting to a wired line or a network interface for connecting to a wireless line. For example, the computing device 200 can be connected to other computing devices 200-1 through the network 50.

[0062] The memory 250 stores program modules that implement various functions of the computing device 200. The processor 230 implements various functions corresponding to these program modules by executing each of these program modules. When executing the modules, the processor 230 may read these modules from the internal memory 240 and then execute them.

[0063] However, the hardware structure of the computing device 200 is not limited to Figure 2 For example, each program module may also be stored in the internal memory 240. In this case, the computing device 200 may not have the memory 250.

[0064] As described above, the thermal imaging camera 100 includes at least a processor 230 and an internal memory 240 storing instructions that can be executed by the processor 230. In particular, Figure 1 The thermal imaging camera 100 is operated by the processor 230 executing instructions including various functional blocks or steps included in the thermal imaging camera 100 .

[0065] Figure 3 FIG. 1 is a flow chart schematically illustrating a process of detecting shutter maloperation by the thermal imaging camera 100 according to an embodiment of the present invention.

[0066] First, when the mechanical shutter 120 is operated to calibrate the thermal imaging sensor 130, the control unit 110 collects external sound sources before and after the operation of the shutter through the microphone 140 (S31). At this time, in order to improve accuracy, the control unit 110 can remove the common sound source determined as noise from the external sound source.

[0067] Furthermore, the control unit 110 compares the collected external sound source with the shutter operation sound source (i.e., reference sound source) stored in the storage unit 115 (S31). According to the comparison result, if the similarity between the two sound sources exceeds a predetermined threshold, the control unit 110 determines that the mechanical shutter 120 has performed a correct opening and closing operation. On the contrary, according to the comparison result, if the similarity is lower than the threshold, the control unit 110 provides an indication of a shutter malfunction of the thermal imaging camera 100 (S35).

[0068] Can be Figure 4 The flowchart is more specific Figure 3these processes in .

[0069] First, the control unit 110 controls the mechanical shutter 120 to close by a control signal to the shutter controller 125 (S41). When the mechanical shutter 120 is closed as described above, the thermal imaging sensor 130 captures a thermal image of the thermal imaging camera 100 (S42).

[0070] Afterwards, the control unit 110 calculates the correction offset related to the thermal image (S43). Specifically, the control unit 110 calculates a separate correction offset according to the pixels included in the captured thermal image. For example, the separate correction offset can be stored in the storage unit 115 in an array form based on the position of the pixel.

[0071] As described above, after calculating the correction offset, the control unit 110 controls the mechanical shutter 120 to open through the shutter controller 125 (S44), and performs secondary photography of the external thermal image through the thermal imaging sensor 130 (S45). At this time, the control unit 110 applies the calculated individual correction offset according to the pixels included in the secondary photographed thermal image, thereby obtaining a corrected clear thermal image (S46).

[0072] In addition, the microphone 140 measures the sound source during a predetermined time period, and the predetermined time includes before and after the time point of conversion to the open / closed state (S51, S56). At this time, the control unit 110 determines whether the measured sound source is consistent with the operating sound source of the shutter stored in the storage unit 115 (i.e., the reference sound source) (S52, 57). This consistency can be determined based on whether the similarity (correlation) between the two compared sound sources exceeds a predetermined threshold. In other words, this is the same concept as whether the difference in the feature values ​​of the two sound sources is less than a predetermined reference value. As a result, if it is determined to be consistent, the normal process of shooting thermal imaging is performed (S42, S45).

[0073] Specifically, the above consistency can be determined by comparing the frequency (Hz) or level (dB) of the measured sound source with the reference sound source. In addition, in order to achieve more accurate judgment, the frequency (Hz) and level (dB) of the sound source can also be taken into account at the same time. Figure 5 It is a graph comparing the center frequencies and levels of the sound source 15 measured by the microphone 140 and the reference sound source 10 . Figure 5 exemplifies a case where the frequency f1 of the measured sound source 15 is greater than the frequency f0 of the reference sound source 10 , and the level L1 of the measured sound source 15 is less than the level L0 of the reference sound source 10 .

[0074] For example, when the difference between the frequency of the measured sound source and the frequency of the reference sound source exceeds a first reference value, and the difference between the level of the sound source and the level of the reference sound source exceeds a second reference value, the control unit 110 may determine that the two sound sources are inconsistent (i.e., an erroneous operation has occurred in the operation of the mechanical shutter 120). This is because, if there is only a frequency similarity or a level similarity between the two sound sources, the measured sound source may be caused by external noise rather than by the operation of the mechanical shutter 120.

[0075] If the above similarity judgment results are inconsistent, it means that the shutter has been misoperated, so the control unit 110 outputs a misoperation reminder (S53, S58). In particular, after the step of notifying the misoperation reminder when performing shutter closing control (S53), the thermal imaging sensor 130 performs a secondary shooting of the external thermal image (S54), and the control unit 110 applies the existing correction offset obtained before the misoperation and stored in the storage unit 115 to the thermal image (specifically, each pixel included in the thermal image) of the secondary shooting (S55).

[0076] Although in Figure 4 In the example, it is shown that whether the shutter has an erroneous operation is determined in both the closing operation and the opening operation of the mechanical shutter 120, but it is obvious that it is also possible to determine whether the shutter has an erroneous operation only in either the closing operation or the opening operation.

[0077] According to the above Figure 4 In the embodiment, whether the measured sound source is consistent with the reference sound source is determined to determine whether the mechanical shutter 120 is operated incorrectly, thereby providing a reminder to the user. Figure 6 In the embodiment, not only is it provided to determine whether the mechanical shutter 120 is misoperated or not, but also it is provided that even if the misoperation occurs, an operation process of the thermal imaging camera can be temporarily dealt with.

[0078] First, the control unit 110 performs the opening and closing operation of the mechanical shutter 120 (S61). At this time, the microphone 140 collects the sound source within a predetermined time including before and after the time point of conversion to the open / closed state (S62). At this time, the control unit 110 analyzes the characteristic value (for example, level, center frequency, bandwidth, etc.) of the collected sound source (S63). If the predetermined analysis result of the difference between the characteristic value of the collected sound source and the characteristic value of the reference sound source (operation sound source) determines that an erroneous operation has occurred in the mechanical shutter 120 ("Yes" of S64), the control unit 110 performs step S68, otherwise ("No" of S64) performs step S65. Since the judgment on whether there is such an erroneous operation (that is, whether the measured sound source is consistent with the reference sound source) is the same as the above judgment on Figure 4 The same as described in , so repeated description will be omitted.

[0079] If the erroneous operation does not occur (No in S64), the control unit 110 calculates the correction offset using the shutter opening and closing operation (S65). The calculation of the correction offset using the shutter opening and closing operation is similar to the calculation of the correction offset using the shutter opening and closing operation described above. Figure 4 The same as the embodiment.

[0080] Specifically, after the control unit 110 closes the mechanical shutter 120 through a control signal to the shutter controller 125 , the thermal imaging sensor 130 takes a thermal image of the thermal imaging camera 100 and calculates the correction offset of the thermal image.

[0081] Then, after the control unit 110 opens the mechanical shutter 120 by means of a control signal to the shutter controller 125, the correction offset is applied to the thermal image currently captured by the thermal imaging camera 100 (secondary capture) (S66). At this time, in order to obtain a clear thermal image, the control unit 110 applies the calculated individual correction offset to correct the captured thermal image according to the pixels included in the secondary captured thermal image (current thermal image).

[0082] The thermal image to which the correction offset is applied may be finally sent in a manner of being stored in the storage unit 115, transmitted over a network, or displayed to a user on the display device 150 (S67).

[0083] If an erroneous operation of the mechanical shutter 120 occurs in step S64 (Yes in S64), the mechanical shutter 120 cannot be opened or closed normally, so the control unit 110 refers to the mapping table pre-stored in the storage unit 115 to estimate (interpolate) the correction offset (S68).

[0084] As described above, such a mapping table can be generated by the control unit 110 and stored in the storage unit 115 during the normal operation of the mechanical shutter 120 , or can be generated and pre-stored in the storage unit 115 through a pre-calibration process before the thermal imaging camera 100 is shipped.

[0085] Specifically, the following Figure 7 Example Figure 6 In the case where the mapping table is pre-generated before the product leaves the factory during operation, Figure 8 Example Figure 6 During the operation of , the mapping table is generated by the control unit 110.

[0086] Reference Figure 7 The shutter operation (S71), sound source collection (S72) and sound source analysis (S73) process are similar to Figure 6 The same, therefore repeated description is omitted.

[0087] In step S74, the control unit 110 determines whether an erroneous operation of the mechanical shutter 120 occurs (S74). Specifically, the erroneous operation is exemplified as an error in which the mechanical shutter 120 is fixed in an open state and cannot be closed normally.

[0088] At this time, if the erroneous operation does not occur ("No" in S74), Figure 6 Similarly, the process of calculating the correction offset using the operation of opening and closing the shutter (S75), applying the correction offset to the photographed thermal image (S76), and transmitting the image (S77) is performed.

[0089] If the erroneous operation occurs (Yes in S74 ), the control unit 110 measures the temperature of the thermal imaging sensor 130 or the mechanical shutter 120 through the temperature sensor 160 ( S78 ), and determines whether the measured temperature satisfies the temperature change condition ( S79 ).

[0090] The temperature change condition refers to a condition where the temperature of the thermal imaging camera 100 changes by more than a reference value compared to the current temperature (e.g., a difference of more than 0.5 degrees), and can be checked at each predetermined period (e.g., 4 minutes and 30 seconds). Therefore, even if there is a temperature change, if the period has not yet arrived, or even if the period has arrived, if the magnitude of the temperature change is less than the reference value, the correction offset may not be changed and the current correction offset may be directly applied.

[0091] However, if the temperature variation condition is satisfied, the current correction offset level is unreliable, and therefore the correction offset is estimated (interpolated) with reference to a mapping table pre-stored in the storage unit 115 when the product is shipped ( S80 ).

[0092] This inferred correction offset is applied to the currently captured thermal image (S76), and a corrected thermal image is finally sent by application of the correction offset (S77).

[0093] Figure 8 Illustrated in Figure 6 The situation in which a mapping table is generated by the control unit 110 during the operation.

[0094] First, the shutter operation (S81), sound source collection (S82), sound source analysis (S83), judgment of the occurrence of erroneous operation (S84), calculation of correction offset using the shutter opening and closing operation (S85), application of the correction offset to the captured thermal image (S87) and sending the image (S88) are similar to the process in Figure 7 The same as in the above description, so repeated description is omitted.

[0095] but, Figure 8The embodiment illustrates a case where the mapping table is generated by the control section 110 when the operation of the mechanical shutter 120 is normal, and therefore in step S85, a process of adding (recording) the calculated correction offset to the mapping table is also required (S86).

[0096] That is, the control unit 110 may add the calculated correction offset to the mapping table stored in the storage unit 115 at each predetermined correction cycle (S86). In such a mapping table, the more correction offsets are added to a specific temperature, the more accurately the correction offset can be inferred (interpolated) in an emergency.

[0097] The calibration cycle is applied differently to a first section from when the thermal imaging camera 100 is powered on until the thermal imaging sensor 130 is stabilized and a second section after the thermal imaging sensor 130 reaches a stable state (normal state).

[0098] For example, in the first interval, since the thermal imaging sensor 130 is in a state that is not yet stable, a shorter calibration cycle (for example, 20 seconds, 40 seconds, 1 minute, etc.) can be applied. In the second interval, since the thermal imaging sensor 130 is in a state that is stable to a certain extent, a longer calibration cycle (for example, 4 minutes and 30 seconds, 10 minutes, etc.) can be applied.

[0099] Then, when the erroneous operation occurs in step S84, the control unit 110 infers (interpolates) the correction offset (S89) by referring to the mapping table stored in the storage unit 115. The inferred correction offset is applied to the currently captured thermal image (S87), and the corrected thermal image is finally sent by applying the correction offset (S88).

[0100] In addition, if Figure 7 and Figure 8 As shown, the erroneous operation of the mechanical shutter 120 may also cause the mechanical shutter 120 to be fixed in an open state and unable to close, but it may also cause the mechanical shutter 120 to be fixed in a closed state and unable to open. As described above, Fig. 9 The operation process of the thermal imaging camera is shown, which can temporarily cope with the situation even when the mechanical shutter 120 is fixed in the closed state.

[0101] First, the shutter operation (S91), sound source collection (S92), sound source analysis (S93), calculation of correction offset using shutter opening and closing operation (S95), storage of the calculated correction offset in a mapping table (S96), application of the correction offset to the captured thermal image (S97), and sending of the image (S98) are similar to the process described in the embodiment of the present invention. Figure 8 The same as in the above description, so repeated description is omitted.

[0102] However, in Fig. 9 In the embodiment of the present invention, in step S94, it is determined whether an erroneous operation of the mechanical shutter 120 being fixed in the closed state occurs (S94). If the erroneous operation does not occur (No in S94), steps S95 to S98 are normally executed.

[0103] On the contrary, if the erroneous operation occurs ("Yes" in S94), the mechanical shutter 120 cannot be opened and the thermal image cannot be taken normally. Therefore, the control unit 110 performs a process of completely resetting the thermal imaging camera 100 itself (S101). If the erroneous operation of opening and closing the mechanical shutter 120 is caused by a problem caused by the controller or wiring, the erroneous operation problem can also be solved by such a reset.

[0104] As described above, after the reset, the control unit 110 controls the mechanical shutter 120 to remain in the open state (S102), considering that if the mechanical shutter 120 is in the closed state again, it may not be opened again.

[0105] Then, the control unit 110 measures the temperature of the thermal imaging sensor 130 or the mechanical shutter 120 through the temperature sensor 160 ( S103 ), and determines whether the measured temperature satisfies the temperature variation condition ( S104 ).

[0106] The temperature change condition refers to a condition where the temperature of the thermal imaging camera 100 changes by more than a reference value compared to the current temperature (e.g., a difference of more than 0.5 degrees), and can be checked at each predetermined period (e.g., 4 minutes and 30 seconds). Therefore, even if there is a temperature change, if the period has not yet arrived, or even if the period has arrived, if the magnitude of the temperature change is less than the reference value, the current correction offset can be directly applied without changing the correction offset.

[0107] However, if the temperature variation condition is satisfied (Yes in S104 ), the current correction offset level is unreliable, so the correction offset is estimated (interpolated) with reference to the mapping table generated by the control unit 110 when the mechanical shutter 110 is operating normally ( S105 ).

[0108] This inferred correction offset is applied to the currently captured thermal image (S97), and a corrected thermal image is finally transmitted by application of the correction offset (S98).

Claims

1. A thermal imaging camera, comprising a processor and a storage unit storing instructions executable by the processor, the thermal imaging camera comprising: A shutter controller, controlling the opening and closing of the shutter of the thermal imaging camera; a microphone for measuring a sound source during the opening and closing of a shutter of the thermal imaging camera; The storage unit stores a mapping table; The control unit determines whether an erroneous operation of the shutter occurs by determining whether the measured sound source is consistent with the operating sound source of the shutter. In the event of an erroneous operation, the control unit infers a correction offset by referring to the mapping table, and corrects the captured thermal image by using the inferred correction offset.

2. The thermal imaging camera according to claim 1, wherein: The mapping table includes data pairs that perform a one-to-one matching between the temperature measured by the temperature sensor and the correction offset.

3. The thermal imaging camera according to claim 2, wherein: If the specific temperature does not exist in the mapping table, the control unit infers the correction offset for the specific temperature by interpolating data pairs of temperature and correction offset included in the mapping table.

4. The thermal imaging camera according to claim 1, wherein: The mapping table is generated through a pre-calibration process and stored in the storage unit before the thermal imaging camera is shipped out of the factory.

5. The thermal imaging camera according to claim 4, wherein: The control unit estimates the correction offset only when the temperature measured by the temperature sensor satisfies the temperature change condition. The temperature variation condition is a condition in which the measured temperature varies more than a reference value compared with a current temperature.

6. The thermal imaging camera according to claim 5, wherein: The temperature variation condition is checked at every predetermined period.

7. The thermal imaging camera according to claim 1, wherein: When the erroneous operation of the shutter does not occur, the control unit calculates a correction offset through the opening and closing operation of the shutter, and stores the calculated correction offset in a mapping table.

8. The thermal imaging camera according to claim 7, wherein: The control unit calculates the correction offset in each predetermined correction cycle and stores it in a mapping table. The correction cycle is applied differently to a first section until the power of the thermal imaging camera is turned on and the thermal imaging sensor is stabilized and to a second section until the thermal imaging sensor reaches a stable state.

9. The thermal imaging camera according to claim 8, wherein: The correction period of the first interval is shorter than the correction period of the second interval.

10. The thermal imaging camera according to claim 1, wherein: The shutter misoperation refers to the error that the shutter cannot be opened and fixed in the closed state. The control unit controls to keep the shutter open after resetting the thermal imaging camera, and refers to the mapping table to infer the correction offset only when the temperature measured by the temperature sensor satisfies the temperature change condition, The temperature variation condition is a condition in which the measured temperature varies more than a reference value compared with a current temperature.

Images