An infrared temperature measurement device calibration method, infrared temperature measurement method and system

Abstract

The application discloses an infrared temperature measuring device calibration method, and the infrared temperature measuring device comprises a thermoelectric element and a thermistor, and the method comprises the following steps: setting a calibration environment temperature, a first calibration temperature and a second calibration temperature of a target object; obtaining a first measurement voltage of the thermoelectric element based on the first calibration temperature, and obtaining a second measurement voltage of the thermoelectric element based on the second calibration temperature; calculating a sensitivity coefficient of the thermoelectric element based on the first measurement voltage, the second measurement voltage, the first calibration temperature and the second calibration temperature; calculating an actual environment temperature based on the sensitivity coefficient of the thermoelectric element, the target calibration temperature and the corresponding measurement voltage; and calculating a zero-power resistance value of the thermistor based on the actual environment temperature, a thermistor measurement value and a thermistor constant. The scheme can improve the accuracy of infrared temperature measuring device parameter calibration, thereby improving the accuracy of infrared temperature measurement.

Description

Technical Field

[0001] This invention relates to the field of infrared temperature measurement technology, specifically to a calibration method for infrared temperature measurement equipment, an infrared temperature measurement method, and a system. Background Technology

[0002] Thermocouple devices can be fabricated using the thermoelectric effect principle, and several thermocouples connected in series can be used to create a thermopile sensor. Infrared thermometry uses a thermopile sensor to sense the temperature difference on the surface of an object, converts the temperature difference into voltage, and thus obtains the surface temperature of the object.

[0003] Infrared temperature measurement equipment contains two sensors: a thermistor to measure the ambient temperature and a thermopile to measure the target temperature. Because different thermistors and thermopiles have different constant parameters, each product needs to be calibrated during manufacturing.

[0004] Existing equipment parameter calibration methods involve sequentially measuring two blackbodies and calculating the corresponding parameter values, assuming the equipment temperature matches the ambient temperature. This calibration method requires a temperature-controlled chamber. However, errors in the chamber's control equipment or human error can lead to discrepancies between the actual and set temperatures. Furthermore, the product's own temperature can vary depending on its placement and duration, ultimately resulting in measurement errors. When the ambient temperature deviates during calibration, the temperature measurement results for the target object will exhibit significant errors. Summary of the Invention

[0005] In view of the above problems, this solution proposes a calibration method, infrared temperature measurement method and system for infrared temperature measurement equipment. It can calculate the actual ambient temperature of the constant temperature room based on the actual measurement values ​​during the calibration process, and reduce the measurement error caused by such ambient temperature deviation through algorithms, thereby improving the accuracy of infrared temperature measurement.

[0006] According to a first aspect of the present invention, a calibration method for an infrared temperature measuring device is provided. The infrared temperature measuring device includes a thermistor and a thermopile. First, a calibration ambient temperature, a first calibration temperature of a target object, and a second calibration temperature are set.

[0007] Then, the first measurement voltage of the thermopile is obtained based on the first calibration temperature, and the second measurement voltage of the thermopile is obtained based on the second calibration temperature; and the sensitivity coefficient of the thermopile is calculated based on the first measurement voltage, the second measurement voltage, the first calibration temperature and the second calibration temperature.

[0008] Next, based on the sensitivity coefficient, the target calibration temperature, and the corresponding measurement voltage, the actual ambient temperature is calculated; finally, based on the actual ambient temperature, the thermistor measurement value, and the thermistor constant, the zero-power resistance value of the thermistor is calculated.

[0009] The above calibration method calculates the actual ambient temperature of the constant temperature chamber based on the thermistor and thermopile voltage measurements during the calibration process, and then calibrates the zero-power resistance value of the thermistor based on the actual ambient temperature. This method can reduce the impact of ambient temperature deviation on product calibration.

[0010] Alternatively, in the above calibration method, the sensitivity coefficient K of the thermopile can be calculated using the following formula:

[0011]

[0012] T t2 The second calibration temperature, T t1 The first calibration temperature, The first measured voltage, This is the second measured voltage.

[0013] Alternatively, in the above calibration method, the actual ambient temperature T can be calculated using the following formula. r :

[0014]

[0015] or

[0016]

[0017] Alternatively, in the above calibration method, the zero-power resistance value R of the thermistor is calculated using the following formula. 25 :

[0018]

[0019] Among them, R T Here, B is the measured value of the thermistor, and T is the thermistor constant. r T represents the actual ambient temperature. a To calibrate the ambient temperature, T a =25.

[0020] According to a second aspect of the present invention, an infrared temperature measurement method based on an infrared temperature measuring device is provided, comprising: calculating the current ambient temperature value based on the thermistor measurement value of the infrared temperature measuring device, the thermistor constant, and the zero-power resistance value of the thermistor obtained by the calibration method described above;

[0021] The target object's temperature is calculated based on the thermopile's output voltage, the thermopile sensitivity coefficient obtained using the calibration method described above, and the current ambient temperature.

[0022] Optionally, in the above infrared thermometry method, the current ambient temperature T is calculated using the following formula. at :

[0023]

[0024] Among them, R T This represents the current measured value of the thermistor, and B is the thermistor constant.

[0025] Alternatively, in the above infrared thermometry method, the temperature value T of the target object can be calculated using the following formula. t :

[0026]

[0027] Where Vout is the output voltage value, K is the calibrated thermopile sensitivity coefficient value, and T at The ambient temperature is the current temperature. According to a third aspect of the present invention, an infrared temperature measurement system is provided, comprising: a calibration module, a measurement module, and a calculation module.

[0028] The calibration module can calibrate the sensitivity coefficient of the thermopile and the zero-power resistance value of the thermistor according to the calibration method described above.

[0029] The measurement module can measure the thermistor value and the thermopile output voltage value. The calculation module can calculate the current ambient temperature value based on the thermistor value obtained by the measurement module, the thermistor constant, and the zero-power resistance value of the thermistor calibrated by the calibration module. Based on the current ambient temperature value, the sensitivity coefficient calibrated by the calibration module, and the output voltage value measured by the measurement module, the calculation module can calculate the temperature value of the target object.

[0030] According to the present invention, the actual ambient temperature is calculated by using a formula based on the measured values ​​of the thermistor and the voltage measured values ​​of the thermopile during the calibration process. Then, the corresponding zero-power resistance value of the thermistor is calculated based on the actual ambient temperature during calibration. This ensures that the product calibration results are not affected by the ambient temperature deviation during calibration, thereby reducing measurement errors when the product measures the temperature of the target object.

[0031] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0032] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0033] Figure 1 A flowchart illustrating an infrared temperature measurement device calibration method 100 according to an embodiment of the present invention is shown.

[0034] Figure 2 A schematic diagram of an infrared temperature measurement system 200 according to an embodiment of the present invention is shown. Detailed Implementation

[0035] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0036] In the production of infrared temperature measurement equipment, blackbodies are frequently used as the target object for temperature measurement. A blackbody is an idealized object that absorbs all incoming electromagnetic radiation without any reflection or transmission. That is, a blackbody has an absorption coefficient of 1 and a transmission coefficient of 0 for any wavelength of electromagnetic wave. During measurement, the blackbody is typically placed in a constant-temperature water bath, and adjusting the temperature of the bath changes the temperature of the blackbody.

[0037] Existing infrared temperature measurement devices acquire the temperature of a target object through an infrared temperature sensor. This sensor includes a thermistor for measuring the ambient temperature and a thermopile for measuring the temperature of the target object. The thermistor's resistance value R... T and ambient temperature T a The relation is:

[0038]

[0039] Where R 25 The B value is a constant of the thermistor, and R is measured. T The value of T can be used to calculate the current ambient temperature T. a .

[0040] Thermopile output voltage Vout, ambient temperature T a and target temperature T t The relation is:

[0041] Vout=K*[(T t +273.15) 4 -(T a +273.15) 4 ]

[0042] Where K is the thermopile sensitivity coefficient, and T a The resistance R of the thermistor has been measured. TBy calculating and then measuring the value of Vout, the current target temperature T can be calculated. t The value. But in reality, due to the R value of each sensor... 25 Since the values ​​of K and R are different, the target object temperature calculated using the above formula will have a certain deviation. Therefore, during production, it is necessary to perform a calibration operation on each product to calculate the corresponding R for each product. 25 And K.

[0043] When calibrating a product, a constant-temperature chamber is required, typically set at 25 degrees Celsius. Two constant-temperature water baths and a blackbody within them are needed as the target objects for temperature measurement. The water bath temperatures are typically set at 37 degrees Celsius and 42 degrees Celsius. With the equipment temperature and ambient temperature consistent, the two blackbodies are measured sequentially. Since the ambient temperature and the target object temperature are known, the R value corresponding to the current equipment can be calculated using the aforementioned formula. 25 And the K value.

[0044] Existing calibration methods require operation in a temperature-controlled chamber. Errors in the chamber's control equipment or operator-induced measurement errors can lead to discrepancies between the actual and set temperatures, affecting the accuracy of product parameter calibration. Furthermore, as the product remains in the chamber longer, discrepancies may arise between the product's internal temperature and the ambient temperature, further contributing to measurement errors.

[0045] To reduce product measurement errors, this solution provides a calibration method, infrared temperature measurement method, and system for infrared temperature measurement equipment. During product calibration, the actual ambient temperature value is calculated based on the thermopile voltage measurement value during the calibration process. Then, the parameters of the thermistor are determined based on the actual ambient temperature value, thereby improving the accuracy of product calibration. This also reduces the error in measuring the temperature of the target object during infrared temperature measurement.

[0046] Infrared thermometers mainly consist of an optical system, a photodetector, a signal amplifier and processor, and a display unit. They convert infrared radiation energy into electrical signals for output. Infrared thermometers can communicate with computers for statistical analysis of measurement data. Before leaving the factory, infrared thermometers must be calibrated to accurately display the temperature of the target object.

[0047] Figure 1 A flowchart illustrating a calibration method 100 for an infrared temperature measurement device according to an embodiment of the present invention is shown. Figure 1 As shown, the method 100 begins with step S110, which sets the calibration ambient temperature, the first calibration temperature of the target object, and the second calibration temperature.

[0048] When calibrating infrared thermometers, a temperature-controlled chamber with a stable ambient temperature is typically required. The temperature of the chamber is generally set at the calibration ambient temperature (25 degrees Celsius) to maintain stability, with a tolerance of ±1 degree Celsius. Additionally, two temperature-controlled water baths are needed. The blackbody is placed in these baths as the temperature measurement target. The water bath temperatures can be set to a first calibration temperature (37 degrees Celsius) and a second calibration temperature (42 degrees Celsius). The temperature calibration in this embodiment is merely exemplary; the calibration value can be adjusted according to the application scenario and applicable scope of the infrared thermometer.

[0049] Then, step S120 is executed to obtain the first measurement voltage of the thermopile based on the first calibration temperature, and the second measurement voltage of the thermopile based on the second calibration temperature.

[0050] A thermopile consists of multiple thermocouples. When the temperature of the measuring ends of each thermocouple rises, a thermoelectric potential is generated between the thermocouples. The sum of the voltages at the output end can be obtained as the final measured voltage.

[0051] In one embodiment of the present invention, the target blackbody temperature is 37 degrees Celsius during the first measurement, and the thermopile measurement voltage is MV. (37,Tr) During the second measurement, the target blackbody temperature was 42 degrees Celsius, and the thermopile measurement voltage was MV. (42,Tr) T r This refers to the actual ambient temperature of the constant temperature room.

[0052] Next, step S130 is executed to calculate the sensitivity coefficient of the thermopile based on the first measurement voltage, the second measurement voltage, the first calibration temperature, and the second calibration temperature.

[0053] Based on the thermopile's output voltage Vout and ambient temperature T a and the target object temperature T t Relationship:

[0054] Vout=K*[(T t +273.15) 4 -(T a +273.15) 4 ]

[0055] The following two equations can be derived:

[0056] MV (Tt1,Tr) =K*[(T t1 +273.15) 4 -(T r +273.15) 4 ]

[0057] MV(Tt2,Tr) =K*[(T t2 +273.15) 4 -(T r +273.15) 4 ]

[0058] Where K is the thermopile sensitivity coefficient, and T r The actual ambient temperature of the constant temperature room, T t2 The second calibration temperature, T t1 For the first calibration temperature, MV (Tt1,Tr) For the first measured voltage, MV (Tt2,Tr) This is the second measurement voltage. The thermopile sensitivity coefficient K can be calculated by solving the above equation:

[0059]

[0060] Then, step S140 is executed to calculate the actual ambient temperature based on the thermopile sensitivity coefficient, the target calibration temperature, and the corresponding measurement voltage.

[0061] That is, the calculated thermopile sensitivity coefficient K is substituted into any of the above equations to calculate the actual ambient temperature T during calibration. r ,Right now:

[0062]

[0063] or After calculating the actual ambient temperature, step S150 can be executed to calculate the zero-power resistance value of the thermistor based on the actual ambient temperature, the measured value of the thermistor, and the thermistor constant.

[0064] Because the resistance of the thermistor changes with temperature, R 25 This refers to the zero-power resistance value of the thermistor at room temperature (25 degrees Celsius). Since the actual ambient temperature may change during calibration, the corresponding R... 25 It will also change accordingly.

[0065] Based on the resistance value R of the thermistor T and ambient temperature T r Relationship:

[0066]

[0067] The thermistor value R was measured. T The calculated actual ambient temperature T r The zero-power resistance value R of the thermistor can be calculated by substituting the thermistor constant B into the following formula. 25 :

[0068]

[0069] Among them, R T Here, B is the measured value of the thermistor, and T is the thermistor constant. r T represents the actual ambient temperature. a To calibrate the ambient temperature, T a =25.

[0070] After calibrating the infrared thermometer, it can be used for infrared temperature measurement. To obtain accurate temperature readings, the distance between the thermometer and the test target must be within a suitable range. The resistance R of the thermistor is then measured. T And the output voltage value Vout of the thermopile.

[0071] First, based on the thermistor measurement value R of the infrared temperature measurement device T Thermistor constant B, and the zero-power resistance value R of the thermistor obtained by the above calibration method. 25 Calculate the current ambient temperature value T at .

[0072] The current ambient temperature T can be calculated using the following formula. at :

[0073]

[0074] Among them, R T Here, B represents the current measured value of the thermistor, and B is the thermistor constant. The value of B can be calculated by measuring the resistance at 25 degrees Celsius and 50 degrees Celsius (or 85 degrees Celsius): B = T1T2Ln(R T1 / R T2 The value of B is calculated as (T2 - T1), where T1 = 298.15 K and T2 = 323.15 K. The B value is positively correlated with the product's temperature coefficient of resistance; that is, the larger the B value, the larger the temperature coefficient of resistance. The B value is generally between 2000 and 6000.

[0075] Then, based on the thermopile's output voltage value Vout, the thermopile sensitivity coefficient value K obtained by the above calibration method, and the current ambient temperature value T... at The temperature value T of the target object was calculated. t :

[0076]

[0077] Using the above calibration method, several infrared thermometers were used to measure the temperature of the target object, and the following measurement results were obtained:

[0078]

[0079]

[0080]

[0081] The above measurement results show that, with a calibration ambient temperature of 25.8 degrees Celsius and calibration blackbody temperatures of 37 and 42 degrees Celsius, although there is a deviation of 0.8 degrees Celsius in the calibration ambient temperature, the maximum error of the final product measurement result is 0.23 degrees Celsius, and good measurement results have been obtained.

[0082] Figure 2 A schematic diagram of an infrared temperature measurement system 200 based on an infrared temperature measurement device according to an embodiment of the present invention is shown. Figure 2 As shown, the system 200 includes a calibration module 210, a measurement module 220, and a calculation module 230.

[0083] The calibration module 210 is used to calibrate the sensitivity coefficient of the thermopile and the zero-power resistance value of the thermistor.

[0084] When calibrating the parameters of the infrared temperature measuring device, the calibration module 210 can perform parameter calibration based on the calibration method provided in the embodiments of the present invention.

[0085] First, set the calibration ambient temperature, the first calibration temperature of the target object, and the second calibration temperature. Then, obtain the first measurement voltage of the thermopile based on the first calibration temperature, and the second measurement voltage of the thermopile based on the second calibration temperature. Next, calculate the sensitivity coefficient of the thermopile based on the first measurement voltage, the second measurement voltage, the first calibration temperature, and the second calibration temperature. Subsequently, the actual ambient temperature can be calculated based on the sensitivity coefficient, the target calibration temperature, and the corresponding measurement voltage. Finally, the zero-power resistance value of the thermistor is calculated based on the calculated actual ambient temperature, the thermistor measurement value, and the thermistor constant.

[0086] The measurement module 220 is used to measure the thermistor value and the output voltage value of the thermopile.

[0087] The calculation module 230 is used to calculate the current ambient temperature value based on the thermistor value obtained by the measurement module 220, the thermistor constant, and the zero-power resistance value of the thermistor calibrated by the calibration module 210. Based on the calculated current ambient temperature value, the sensitivity coefficient calibrated by the calibration module 210, and the output voltage value measured by the measurement module 220, the calculation module 230 calculates the temperature value of the target object.

[0088] The calibration method for infrared temperature measurement equipment provided by this invention calculates the actual ambient temperature using a formula based on the measured values ​​of the thermistor and the voltage measured value of the thermopile during the calibration process. Then, the corresponding zero-power resistance value of the thermistor is calculated based on the actual ambient temperature during calibration. This ensures that the product calibration results are not affected by the ambient temperature deviation during calibration, thereby reducing measurement errors when the product measures the temperature of the target object.

[0089] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0090] Similarly, it should be understood that, in order to streamline this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into this detailed description, wherein each claim itself is a separate embodiment of the invention.

[0091] Those skilled in the art will understand that modules, units, or components of the devices disclosed in the examples herein can be arranged in the devices described in this embodiment, or alternatively, can be located in one or more devices different from the devices in this example. The modules in the foregoing examples can be combined into a single module or, in addition, can be divided into multiple sub-modules.

[0092] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0093] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0094] Furthermore, some of the embodiments are described herein as methods or combinations of method elements that can be implemented by a processor of a computer system or by other means of performing functions. Therefore, a processor having the necessary instructions for implementing a method or method element forms means for implementing that method or method element. Furthermore, the elements described herein in the apparatus embodiments are examples of means for implementing functions performed by elements for the purposes of carrying out the invention.

[0095] As used herein, unless otherwise specified, the use of ordinal numbers such as “first,” “second,” “third,” etc., to describe ordinary objects merely indicates different instances of similar objects and is not intended to imply that the objects being described must have a given order in time, space, ordering, or any other manner.

[0096] Although the invention has been described with respect to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and edibility purposes, and not for the purpose of interpreting or limiting the subject matter of the invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the invention is illustrative rather than restrictive, and the scope of the invention is defined by the appended claims.

Claims

1. A calibration method for an infrared temperature measuring device, wherein the infrared temperature measuring device comprises a thermistor and a thermopile, characterized in that, include: Set the calibration ambient temperature, the first calibration temperature and the second calibration temperature of the target object; A first measurement voltage of the thermopile is obtained based on the first calibration temperature, and a second measurement voltage of the thermopile is obtained based on the second calibration temperature. The thermopile sensitivity coefficient is calculated based on the first measurement voltage, the second measurement voltage, the first calibration temperature, and the second calibration temperature, including the following steps: The sensitivity coefficient K of the thermopile is calculated using the following formula: ； This is the second calibration temperature. The first calibration temperature, The first measured voltage, The second measured voltage; Based on the thermopile sensitivity coefficient, target calibration temperature, and corresponding measurement voltage, the actual ambient temperature is calculated, including the following steps: The actual ambient temperature is calculated using the following formula. : ； or ； The zero-power resistance value of the thermistor is calculated based on the actual ambient temperature, the measured value of the thermistor, and the thermistor constant, including the following steps: The zero-power resistance value of the thermistor is calculated using the following formula. : ； in, The thermistor measurement value, where B is the thermistor constant. This refers to the actual ambient temperature. To calibrate the ambient temperature, .

2. An infrared temperature measurement method based on an infrared temperature measuring device, characterized in that, include: The current ambient temperature value is calculated based on the thermistor measurement value of the infrared temperature measuring device, the thermistor constant, and the zero-power resistance value of the thermistor obtained by the calibration method as described in claim 1. The target object temperature is calculated based on the thermopile's output voltage, the thermopile sensitivity coefficient obtained by the calibration method described in claim 1, and the current ambient temperature.

3. The infrared temperature measurement method according to claim 2, characterized in that, The steps for calculating the current ambient temperature based on the thermistor measurement value, thermistor constant, and the zero-power resistance value of the thermistor from the infrared temperature measurement device include: The current ambient temperature value is calculated using the following formula. : ； in, This represents the current measured value of the thermistor, and B is the thermistor constant.

4. The infrared temperature measurement method according to claim 3, characterized in that, The temperature value of the target object is calculated using the following formula. : ； Where Vout is the output voltage value, and K is the calibrated thermopile sensitivity coefficient value. This represents the current ambient temperature.

5. An infrared temperature measurement system, characterized in that, include: A calibration module is used to calibrate the sensitivity coefficient of the thermopile and the zero-power resistance value of the thermistor, wherein the calibration module is used to calibrate the sensitivity coefficient of the thermopile and the zero-power resistance value of the thermistor according to the calibration method described in claim 1. The measurement module is used to measure the thermistor value and the output voltage value of the thermopile; The calculation module is used to calculate the current ambient temperature value based on the thermistor value obtained by the measurement module, the thermistor constant, and the zero-power resistance value of the thermistor calibrated by the calibration module. Based on the current ambient temperature value, the sensitivity coefficient calibrated by the calibration module, and the output voltage value measured by the measurement module, the calculation module is used to calculate the temperature value of the target object.

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