CN114878003A - Infrared temperature measurement method based on response rate correction - Google Patents
Infrared temperature measurement method based on response rate correction Download PDFInfo
- Publication number
- CN114878003A CN114878003A CN202210278769.4A CN202210278769A CN114878003A CN 114878003 A CN114878003 A CN 114878003A CN 202210278769 A CN202210278769 A CN 202210278769A CN 114878003 A CN114878003 A CN 114878003A
- Authority
- CN
- China
- Prior art keywords
- temperature
- response rate
- infrared
- coke
- focal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000004044 response Effects 0.000 title claims abstract description 155
- 238000000034 method Methods 0.000 title claims abstract description 59
- 238000012937 correction Methods 0.000 title claims abstract description 49
- 238000009529 body temperature measurement Methods 0.000 title claims abstract description 32
- 239000000571 coke Substances 0.000 claims abstract description 60
- 230000005855 radiation Effects 0.000 claims abstract description 46
- 230000008859 change Effects 0.000 claims abstract description 40
- 238000001514 detection method Methods 0.000 claims abstract description 12
- 238000013507 mapping Methods 0.000 claims abstract description 5
- 230000008569 process Effects 0.000 claims description 24
- 230000004907 flux Effects 0.000 claims description 10
- 230000036760 body temperature Effects 0.000 claims description 9
- 238000012935 Averaging Methods 0.000 claims description 3
- 238000002474 experimental method Methods 0.000 claims description 3
- 238000004861 thermometry Methods 0.000 claims description 2
- 230000000007 visual effect Effects 0.000 claims description 2
- 230000005457 Black-body radiation Effects 0.000 description 4
- 238000003384 imaging method Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000012886 linear function Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 230000035807 sensation Effects 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J5/10—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors
- G01J5/12—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using thermoelectric elements, e.g. thermocouples
- G01J5/14—Electrical features thereof
- G01J5/16—Arrangements with respect to the cold junction; Compensating influence of ambient temperature or other variables
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J5/0022—Radiation pyrometry, e.g. infrared or optical thermometry for sensing the radiation of moving bodies
- G01J5/0025—Living bodies
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Abstract
The invention provides an infrared temperature measurement method based on responsivity correction, which comprises the following steps: step S1: calibrating the relation between temperature and radiation energy at different constant temperature box temperatures in a laboratory by an off-line calibration method; step S2: the method comprises the steps that the change of the ambient temperature, which causes the change of the coke temperature, is obtained based on the relation between the temperature calibrated in a laboratory and the radiation energy, so that the difference of response rate is caused, the response values measured aiming at the target radiation with the same temperature are different, and the measured temperature is also an inaccurate conclusion; step S3: calibrating the actual response rate characteristics of the infrared temperature measuring instrument at different focal temperatures, thereby obtaining the discrete relation between the response rate and the focal temperature; step S4: and taking the response rate corresponding to a certain coke temperature as a reference, linearly correcting the response rate in the coke temperature change interval and mapping the response rate to the reference response rate, so that the infrared temperature measuring instrument keeps consistent detection stability and accuracy.
Description
Technical Field
The invention relates to the technical field of infrared temperature measurement, in particular to an infrared temperature measurement method based on responsivity correction.
Background
The existing infrared temperature measurement method is to deploy a constant temperature black body as a temperature calibration source on a temperature measurement site, radiate a target to be measured and the constant temperature black body to a temperature measuring instrument through the same environment, receive the difference of radiation energy of the target to be measured and the constant temperature black body, and calculate the temperature of the temperature calibration source and the response rate to obtain the real-time temperature of the target to be measured.
And part of human body infrared thermometers are inconvenient to deploy constant-temperature black bodies on site as temperature calibration sources, the relationship between the target radiation energy of the black bodies at a plurality of temperature points and the temperature is calibrated in advance through a laboratory, a theoretical relationship curve between the target radiation energy of the black bodies and the temperature is obtained through correlation fitting, and as shown in figure 1, when the actual target is measured in temperature, the radiation energy value of the target to be measured is received, and the actual temperature of the target to be measured is obtained through conversion calculation of the temperature curve.
The temperature measuring method can be applied to actual engineering, but after the temperature measuring instrument is started in a cold state or restarted in a power-off state, the temperature of the focal plane of the temperature measuring detector in the temperature measuring instrument does not reach thermal balance within a period of time, namely the temperature of the focal plane is not stable, and under the condition that the temperature of the focal plane is unstable, the temperature of a target measured by the temperature measuring method is inaccurate, so that the temperature measuring precision and accuracy are affected in the whole temperature measuring process. One obvious characteristic of the uncooled long-wave infrared detector is that the response rate of the detector to target detection changes along with the change of the coke temperature, and particularly, the change of the coke temperature is caused by the influence of environmental factors such as environmental temperature, humidity, air flow, wind direction and the like, so that the output response rate changes, wherein the change depends on the manufacturing process, detection materials, packaging types, whether a TEC refrigerator is provided or not and the like of a detector manufacturer. The change of the response rate causes the change of the output response value after receiving the radiation energy, and directly influences the misjudgment of the temperature measurement data.
Patent document CN112067138A (application number: 202010942723.9) discloses a temperature measurement and calibration method and a temperature measurement and calibration device for an infrared detector, which include the following steps: detecting and marking the position of a dead point through a gray difference value between adjacent pixel points in a black body background image acquired by an infrared detector; the method comprises the steps that an infrared detector obtains black body images of black bodies with different temperatures, eliminates abnormal calibration points in the black body images and obtains a temperature calibration model; and obtaining a temperature compensation model through the black body temperature value and the black body real temperature value acquired by the infrared detector, and correcting the temperature according to the temperature compensation model.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide an infrared temperature measurement method based on responsivity correction.
The invention provides an infrared temperature measurement method based on responsivity correction, which comprises the following steps:
step S1: calibrating the relation between temperature and radiation energy at different constant temperature box temperatures in a laboratory by an off-line calibration method;
step S2: the method comprises the steps that the change of the ambient temperature, which causes the change of the coke temperature, is obtained based on the relation between the temperature calibrated in a laboratory and the radiation energy, so that the difference of response rate is caused, the response values measured aiming at the target radiation with the same temperature are different, and the measured temperature is also an inaccurate conclusion;
step S3: calibrating the actual response rate characteristics of the infrared temperature measuring instrument at different focal temperatures, thereby obtaining the discrete relation between the response rate and the focal temperature;
step S4: and taking the response rate corresponding to a certain coke temperature as a reference, linearly correcting the response rate in the coke temperature change interval and mapping the response rate to the reference response rate, so that the infrared temperature measuring instrument keeps consistent detection stability and accuracy.
Preferably, the step S1 adopts: in the calibration process, the temperature measuring instrument is placed in a constant temperature box, the constant temperature boxes are respectively set to be at preset temperatures, meanwhile, the black body is placed in front of the temperature measuring instrument to radiate within a preset range, and the temperature of the black body is respectively set to be at preset values; and after the temperature of each thermostat is stable, recording the AD value of the radiation energy conversion of the human body infrared temperature measuring instrument and the current blackbody temperature value, and obtaining a plurality of groups of relationships between the AD value and the temperature of the target radiation energy.
Preferably, the response rate includes: the responsivity of the focal plane array unit of the uncooled infrared long-wave detector is defined as the ratio of the output voltage of each array unit to the corresponding incident radiation flux value.
Preferably, the step S3 adopts: and (3) obtaining the numerical relation between the actual response rate and the coke temperature through an experiment, and obtaining the relation between the response rate and the coke temperature through a least square fitting method.
Preferably, the step S3 adopts: setting constant temperature as a preset value in a thermostat, setting 2 black bodies to be placed in a visual field in a preset range in front of an infrared temperature measuring instrument in parallel, wherein the placed distance is consistent with the distance between the black bodies and a target in the actual temperature measuring process, setting the temperatures of the 2 black bodies to be T1 and T2 respectively, ensuring that T1 and T2 have certain temperature difference, and averaging the radiation gray values of the corresponding areas of the 2 black bodies obtained after the infrared temperature measuring instrument receives incident radiation to obtain an AD1 value and an AD2 value respectively; thereby obtaining the response rate at the coke temperature; and acquiring the coke temperature of the detector chip in real time, starting a response rate acquisition program when the preset temperature is changed every time the coke temperature is changed, and calculating the response rate to obtain the discrete relation between the response rate and the coke temperature so as to obtain the response rate corresponding to the continuous coke temperature.
Preferably, the response rate at the focal temperature adopts:
R＝(AD2-AD1)/(T2-T1)
preferably, the discrete relationship between the responsivity and the coke temperature is as follows:
Y＝K*T+B
wherein Y represents a response rate; t represents the coke temperature; k represents a coefficient; b represents a constant.
Preferably, the step S3 adopts: the temperature range of the coke temperature is set to be 0-60 ℃, the interval is 0.5 ℃, if the temperature range of the coke temperature is set to be smaller, the interval is smaller, the change range of the response rate is smaller, and the precision of the correction coefficient is higher.
Preferably, the step S4 adopts: linearly correcting and mapping the response rate in the focal temperature change interval to the reference response rate by using the correction coefficient Rb/Rt; wherein Rb represents a reference response rate; rt represents the corresponding response rate at each calibration focal temperature in the focal temperature change interval.
Preferably, the step S4 adopts: the output response rate is corrected in the process of changing the focal temperature, namely under the condition of the same incident radiation flux value, the output response value of the detector is corrected, so that the infrared human body temperature measuring instrument always keeps a stable response rate characteristic in the process of changing the focal temperature and even after the infrared human body temperature measuring instrument is stabilized, the output response value AD value of the target radiation to be measured is corrected, and the infrared temperature measuring instrument keeps consistent detection stability and accuracy.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention solves the problem that the temperature measuring process can be started only after the temperature is stable after the temperature is started for the first time or is started in a cold state, and simultaneously, the invention does not need to adjust the working parameters of the detector, such as gain, bias voltage, integral time and the like, which can influence the output dynamic range and the working state consistency of the detector in a complicated way and can cause the problems of the change of the integral brightness and contrast of output imaging or image flicker. The operation method of temperature measurement calibration is simplified, and the temperature measurement efficiency of the infrared temperature measurement instrument is improved;
2. the temperature measurement method based on the response rate correction carries out correction compensation aiming at the situation that the response rates are inconsistent in the process of the variation of the coke temperature, reduces the error of an output response value caused by the temperature drift of the coke temperature after the correction compensation, improves the accuracy and precision of temperature measurement, and simultaneously reduces the image non-uniformity variation caused by the inconsistency of the response rates, so that the image imaging effect is better;
3. the correction parameters of the responsivity can be reused for the same batch of detectors with the same characteristics and the same model, and can be applied in the equipment production process in batch without recalibration and repeated calculation. The batch production and the production efficiency of the human body infrared temperature measuring instrument are improved.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a theoretical plot of radiant energy versus target temperature.
FIG. 2 is a graph of radiant energy versus temperature for different focal temperatures.
FIG. 3 is a diagram of response rate calibration.
FIG. 4 is a plot of detector responsivity versus focal temperature.
FIG. 5 is a graph showing the relationship between the pre-and post-responsivity correction and the coke temperature.
FIG. 6 is a graph of radiation energy versus temperature after responsivity correction.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.
Example 1
With the popularization and application of infrared thermal imagers, infrared temperature measuring instruments are used more and more in the fields of monitoring, fire fighting, industrial detection, medical use and the like, but the coke temperature is changed in a cold start process or a period of time after power failure restart of the temperature measuring instrument, and generally, the coke temperature gradually rises to be balanced and stable in a space environment at room temperature and a period of time after start. In the process, along with the change of the coke temperature, the response rate gradually tends to be stable, and the error of the response output caused by the temperature drift is gradually reduced to zero.
Therefore, after the temperature measurement device is started for the first time or is started for a cold time, the temperature measurement process needs to be started after the coke temperature is stable for a period of time, and the waiting time depends on external factors such as the temperature, the humidity, the airflow, the wind direction and the like of the environment. If the temperature measuring instrument always keeps accurate temperature measurement when power-on is needed in the cold start-up change process, the working parameters of the detector, such as gain, bias voltage, integration time and the like, need to be adjusted to ensure the consistency of the response rate output when the coke temperature rises. The working parameters of the infrared detector are adjusted in a segmented manner to ensure the consistency of the output response of the detector under black body radiation with the same configuration temperature, because the parameters such as gain, bias voltage, integration time and the like are specific to all array units of the infrared detector, the completely consistent response rate characteristic of all array units of the detector in the process of the rise of the focal temperature is difficult to ensure, the method is complex to operate, and the consistency of the dynamic range and the working state of the output of the detector is influenced after the working parameters of the detector are adjusted, so that the integral brightness and the contrast of the output imaging are changed or image flicker is caused.
In the temperature measurement process of the human body infrared thermometer, a constant temperature black body is not used as a temperature calibration source, and the relation between the temperature and the radiation energy is calibrated in a laboratory by an off-line calibration method.
The infrared human body temperature measuring instrument is mainly used in an indoor thermostat environment, the temperature measuring target is mainly the body surface temperature of a human body, and the temperature measuring range is 20-50 ℃. Therefore, in the calibration process, the temperature measuring instrument is placed in the constant temperature box, the temperature of the constant temperature box is respectively set to be 20 degrees, 25 degrees and 30 degrees, meanwhile, the black body is placed in front of the temperature measuring instrument to radiate, and the temperature of the black body is respectively set to be 28 degrees, 30 degrees, 32 degrees, 34 degrees, 36 degrees, 38 degrees, 40 degrees, 42 degrees, 44 degrees, 46 degrees, 48 degrees and 50 degrees. After the thermostat is set to a stable temperature, the human body infrared temperature measuring instrument is started, radiation of the black body at different temperatures is adjusted in sequence, after the temperature of the black body and the temperature of the coke are stabilized, the AD value of radiation energy conversion of the human body infrared temperature measuring instrument and the current black body temperature value are recorded, 3 groups of relations between the target radiation energy AD value and the temperature are obtained, wherein curves in the attached drawing 2 are acquired and calibrated respectively corresponding to the thermostat temperatures of 20 degrees, 25 degrees and 30 degrees, the abscissa is the temperature of the black body, the light sensation value of the ordinate is actually the output response AD value, and the relation curve graph 2 is obtained through curve fitting. It can be seen from the figure that 3 curves do not overlap, and even if blackbody radiation with the same temperature is set, the response values obtained on the 3 curves are different, and it can be seen that the response rates on the 3 curves are different, and when target temperature measurement is performed, if the radiation AD value of the target to be measured is 4500, 3 target temperatures are obtained on the corresponding temperature curve. This occurs because the infrared detectors have non-uniform responsivities with the same configuration and the target radiation. The infrared detector's burnt temperature can change along with ambient temperature's change, set for 3 different temperatures when the thermostated container, burnt temperature is stable after infrared thermoscope work period back, also can stabilize on 3 different burnt temperatures, the response rate that different burnt temperatures correspond is actually different, it is not completely unanimous, because ambient temperature's change, lead to the change of burnt temperature, thereby arouse the difference of response rate, the response value that target radiation to the same temperature measured out is also different, the temperature that measures like this is also inaccurate.
Generally, the responsivity of an uncooled infrared long-wave detector focal plane array unit is defined as the ratio of the output voltage of each array unit to the corresponding incident radiation flux value. In a specific experiment process, the radiant flux received by an infrared thermometer detector array unit and the output voltage of a single pixel are difficult to measure, and the difficulty in obtaining accurate numerical values of the two quantities is higher, so that the response rate of the detector pixel is difficult to measure by directly utilizing the ratio of the incident radiant flux to the output voltage. Radiation can be performed by blackbody targets with different temperatures dlt _ T, the response output of receiving different incident radiation is converted to a gray difference value dlt _ AD, and the response rate R of the focal plane detector pixel can be approximately represented as R ═ dlt _ AD/dlt _ T.
And calibrating the response rate of the infrared thermometer, and calibrating the actual response rate characteristics of the infrared thermometer at different focal temperatures. The uncooled long-wave infrared detector chip is mostly vacuum-packaged in a closed container made of ceramics, metal and the like, and heat exchange with the outside is isolated, so that detection efficiency is improved. However, the detector chip is also heated in a working state, so that after the infrared thermometer is powered on, under the influence of the ambient temperature and self heating, the focal temperature of the detector chip is gradually increased and stabilized, and is usually higher than the ambient temperature after stabilization. In order to be compatible with the influence of wide-range changes of the focal temperature on the responsivity, the response characteristic of the infrared detector when the focal temperature rises from 0 ℃ to 60 ℃ needs to be actually measured. As shown in fig. 3, a calibration diagram is schematically shown, in an oven, the temperature of the oven is set to be 25 degrees, 2 black bodies are arranged in a front field of view of the infrared thermometric instrument in the left-right direction, the arrangement distance is consistent with the distance between the black bodies and a target in the actual thermometry process, the temperatures of the 2 black bodies are respectively set to be T1-20 degrees and T2-40 degrees, and a certain temperature difference exists, and the radiation gray values of the left and right 2 areas obtained after the infrared thermometric instrument receives incident radiation are respectively averaged to obtain an AD1 value and an AD2 value. The response rate at the scorched temperature at this time, R, is (AD2-AD 1)/(T2-T1). And the focal temperature of the detector chip can be acquired in real time, according to the acquired focal temperature, when the focal temperature changes by 0.5 ℃, a response rate acquisition program is started, the discrete relation between the response rate and the focal temperature is obtained by calculating the response rate R (AD2-AD1)/(T2-T1), if the temperature of the incubator is set to be 25 ℃, the focal temperature cannot reach 60 ℃ after being stabilized, the temperature of the incubator can be set to be 30 ℃ or higher for calibration, the curve of the response rate along with the change of the focal temperature can cover the change interval of the focal temperature from 0 ℃ to 60 ℃, so that the numerical relation between the actual response rate and the focal temperature is obtained, and the curve of the relation between the response rate and the focal temperature is obtained by a least square fitting method and is shown in fig. 4. As can be seen from the graph, the response rate gradually decreases as the focus temperature rises, and an inflection point appears around 23 degrees, and then the magnitude of the change in response rate is larger in the case of a unit change in focus temperature. In general, since the change trend of the response rate is a piecewise linear relationship, the response rate corresponding to the continuous focal temperature is obtained by expressing Y to K to T + B by an approximate linear relationship function.
Correcting the response rate of the infrared thermometer, wherein the change trend of the response rate is in a piecewise linear relation and gradually decreases along with the rise of the coke temperature, the response rate in a coke temperature change interval can be linearly corrected and mapped onto the reference response rate by taking the response rate corresponding to a certain coke temperature as a reference, a group of correction coefficients Rb/Rt are used for expressing and relating to the coke temperature, Rt is the response rate corresponding to each calibrated coke temperature in the coke temperature change interval, and Rb is the reference response rate. In the invention, the actual using environment and condition of the thermometer are combined, the human body thermometer is arranged in the thermostat for use, the temperature of the thermostat is set to be 25 ℃ which is basically consistent with the temperature of the normal temperature environment, therefore, through multiple times of experimental verification of a plurality of instruments and equipment, under the environment of 25 ℃ of the constant temperature box, the infrared temperature measuring instrument is stable from cold start to the coke temperature, the stabilized coke temperature can not exceed 60 ℃, the response rate corresponding to the 60 deg.c of the temperature is used as the reference response rate in the process of the response rate correction, through the calibrated numerical value table of the responsivity and the coke temperature, the coke temperature is inquired from 0 to 60 ℃, a numerical value table of the responsivity and the coke temperature is arranged every 0.5 ℃, 121 correction coefficients in total are obtained by calculation, in order to reduce correction errors, and when the coke temperature is within the range of 0-60 and is an integral multiple of 0.5, directly calling the calibrated correction coefficient. In other cases, if the coke temperature is in the coke temperature interval corresponding to 121 correction coefficients, because the change trend of the response rate along with the coke temperature is in a piecewise linear relationship, the response rate corresponding to the coke temperature which is a decimal multiple of 0.5 can be obtained through a linear function relation by using two coefficients in the 121 correction coefficients, and then the reference response rate is used for dividing to obtain other correction coefficients.
In the embodiment of the invention, the temperature range of 0-60 ℃ is set for the coke temperature calibration, the interval is 0.5 ℃, if the set coke temperature range is smaller, the interval is smaller, the response rate change range is smaller, and the precision of the correction coefficient is higher. Of course, the calibration data content and the storage space are also increased, and the temperature calibration range and the interval can be adjusted according to the actual situation.
Meanwhile, the responsivity describes the inherent characteristics of the infrared detector, and the 121 correction coefficients can be reused for the same batch of detectors with the same characteristics in the same model, do not need to be calibrated and calculated again, and can be applied to the equipment production process in batches. In actual use, the response rate after correction is the pixel self response rate Rt and the correction coefficient is Rb, and fig. 5 shows a curve of the response rate before and after correction along with the change of the focal temperature. The response rate before and after correction is represented as an average response rate of a certain area in an image or an entire image, actually, one image is composed of n pixels, the response rate of each pixel is not exactly the same as the average response rate, for example, under a certain focal temperature obtained through the calibration, the response rate of the first pixel is R1, the response rate of the second pixel is R2, and the response rate of the nth pixel is Rn, the correction process can also be represented as a first step, under the focal temperature, the response rate of each pixel is corrected to R _ avg (summation and averaging of the response rates of the pixels), that is, the sum of the response rates of the pixels is multiplied by a correction coefficient R _ avg/Rn R _ avg, so that the response rates of all the pixels are basically consistent. And secondly, correcting the average response rate at the focal temperature to the reference response rate, namely multiplying the average response rate by a correction coefficient Rb/R _ avg ═ Rb, and maintaining the response rate of all pixels on the reference response rate after correction, so that the correction method also reduces the image non-uniformity caused by the non-uniformity of the response rate among the pixels, thereby ensuring better image uniformity and better imaging effect.
Application of infrared thermometer response rate. Since the detector output responsivity is originally defined as the ratio of the output voltage of each array element to the corresponding incident radiation flux value. In the embodiment of the invention, assuming that the incident radiation flux value of the target to be measured is I, the output voltages of the detector array units are O1 and O2 under the condition that different focal temperatures correspond to non-responsivity, respectively, so that the ratio of the responsivity is R1/R2 — O1/O2, and the output voltage of the detector array unit can be linearly expressed by an AD value, so that R1/R2 — AD1/AD 2. Therefore, the output response rate is corrected in the process of changing the focal temperature, namely, the output response value (AD value) of the detector is corrected under the condition of the same incident radiation flux value, so that the infrared human body temperature measuring instrument always keeps a stable response rate characteristic in the process of changing the focal temperature and even after the infrared human body temperature measuring instrument is stable, the output response value AD value of the target radiation to be measured is corrected, and the infrared temperature measuring instrument keeps consistent detection stability and accuracy. If R1 corresponds to the response rate during the focus temperature change, R2 corresponds to the stabilized reference response rate, AD1 is the output response value corresponding to the R1 response rate, and AD1 'is the output response value corresponding to the R2 reference response rate, AD1 is actually inaccurate, and AD 1' is corrected to be accurate, then the R1 response rate correction is mapped to R2, that is, the AD1 value correction is mapped to the AD1 'value, so that AD 1' is equal to AD1, i.e. the response rate correction coefficient is equal to AD1, R2/R1. As can be seen from fig. 4, the lower the focus temperature, the higher the response rate, so that after cold start, the received radiant energy response value AD1 becomes larger in the case of blackbody radiation at the same temperature, and after the focus temperature is stabilized, the received radiant energy response value becomes smaller in the case of blackbody radiation at the same temperature, so that the corrected AD 1' is reduced from the AD1 value, and the reduced portion corresponds to the response rate. It can be known from fig. 2 that the 3 temperature curves are not overlapped, which is caused by the inconsistency of the response rates, and after the response rate correction is performed, that is, the output response value (AD value) of the detector is corrected, it can be ensured that the 3 temperature curves are overlapped to form one temperature measurement curve, as shown in fig. 6, and the response rates output by the detector are basically consistent with the change of the focal temperature. When the target is to be detected, no matter the cold start or the hot start or the fluctuation of the coke temperature, the temperature of the target to be detected is accurately obtained by obtaining the AD value corresponding to the target radiation energy and converting the AD value within the detection temperature range or the detection dynamic range of the detector.
In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.
Claims (10)
1. An infrared temperature measurement method based on responsivity correction is characterized by comprising the following steps:
step S1: calibrating the relation between temperature and radiation energy at different constant temperature box temperatures in a laboratory by an off-line calibration method;
step S2: the method comprises the steps that the change of the ambient temperature, which causes the change of the coke temperature, is obtained based on the relation between the temperature calibrated in a laboratory and the radiation energy, so that the difference of response rate is caused, the response values measured aiming at the target radiation with the same temperature are different, and the measured temperature is also an inaccurate conclusion;
step S3: calibrating the actual response rate characteristics of the infrared temperature measuring instrument at different focal temperatures, thereby obtaining the discrete relation between the response rate and the focal temperature;
step S4: and taking the response rate corresponding to a certain coke temperature as a reference, linearly correcting the response rate in the coke temperature change interval and mapping the response rate to the reference response rate, so that the infrared temperature measuring instrument keeps consistent detection stability and accuracy.
2. The infrared temperature measurement method based on responsivity correction as claimed in claim 1, wherein the step S1 employs: in the calibration process, the temperature measuring instrument is placed in a constant temperature box, the constant temperature boxes are respectively set to be at preset temperatures, meanwhile, the black body is placed in front of the temperature measuring instrument to radiate within a preset range, and the temperature of the black body is respectively set to be at preset values; and after the thermostat is set to have stable temperature, recording the AD value converted by the radiation energy of the human body infrared temperature measuring instrument and the current blackbody temperature value, and obtaining a plurality of groups of relationships between the AD value and the temperature of the target radiation energy.
3. The infrared thermometry method based on responsivity correction of claim 1, wherein the responsivity comprises: the responsivity of the focal plane array unit of the uncooled infrared long-wave detector is defined as the ratio of the output voltage of each array unit to the corresponding incident radiation flux value.
4. The infrared temperature measurement method based on responsivity correction as claimed in claim 1, wherein the step S3 employs: and (3) obtaining the numerical relation between the actual response rate and the coke temperature through an experiment, and obtaining the relation between the response rate and the coke temperature through a least square fitting method.
5. The infrared temperature measurement method based on the responsivity correction as claimed in claim 4, wherein the step S3 adopts: setting constant temperature as a preset value in a thermostat, setting 2 black bodies to be placed in a visual field in a preset range in front of an infrared temperature measuring instrument in parallel, wherein the placed distance is consistent with the distance between the black bodies and a target in the actual temperature measuring process, setting the temperatures of the 2 black bodies to be T1 and T2 respectively, ensuring that T1 and T2 have certain temperature difference, and averaging the radiation gray values of the corresponding areas of the 2 black bodies obtained after the infrared temperature measuring instrument receives incident radiation to obtain an AD1 value and an AD2 value respectively; thereby obtaining the response rate at the coke temperature; and acquiring the coke temperature of the detector chip in real time, starting a response rate acquisition program when the preset temperature is changed every time the coke temperature is changed, and calculating the response rate to obtain the discrete relation between the response rate and the coke temperature so as to obtain the response rate corresponding to the continuous coke temperature.
6. The infrared temperature measurement method based on the responsivity correction as claimed in claim 5, wherein the responsivity at the focal temperature adopts:
R＝(AD2-AD1)/(T2-T1)
7. the infrared temperature measurement method based on responsivity correction as claimed in claim 5, wherein the discrete relationship between responsivity and focal temperature is as follows:
Y＝K*T+B
wherein Y represents a response rate; t represents the coke temperature; k represents a coefficient; b represents a constant.
8. The infrared temperature measurement method based on responsivity correction as claimed in claim 1, wherein the step S3 employs: the temperature range of the coke temperature is set to be 0-60 ℃, the interval is 0.5 ℃, if the temperature range of the coke temperature is set to be smaller, the interval is smaller, the change range of the response rate is smaller, and the precision of the correction coefficient is higher.
9. The infrared temperature measurement method based on responsivity correction as claimed in claim 1, wherein the step S4 employs: linearly correcting and mapping the response rate in the focal temperature change interval to the reference response rate by using the correction coefficient Rb/Rt; wherein Rb represents a reference response rate; rt represents the corresponding response rate at each calibration focal temperature in the focal temperature change interval.
10. The infrared temperature measurement method based on responsivity correction as claimed in claim 1, wherein the step S4 employs: the output response rate is corrected in the process of changing the focal temperature, namely under the condition of the same incident radiation flux value, the output response value of the detector is corrected, so that the infrared human body temperature measuring instrument always keeps a stable response rate characteristic in the process of changing the focal temperature and even after the infrared human body temperature measuring instrument is stabilized, the output response value AD value of the target radiation to be measured is corrected, and the infrared temperature measuring instrument keeps consistent detection stability and accuracy.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210278769.4A CN114878003A (en) | 2022-03-21 | 2022-03-21 | Infrared temperature measurement method based on response rate correction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210278769.4A CN114878003A (en) | 2022-03-21 | 2022-03-21 | Infrared temperature measurement method based on response rate correction |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114878003A true CN114878003A (en) | 2022-08-09 |
Family
ID=82666901
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210278769.4A Pending CN114878003A (en) | 2022-03-21 | 2022-03-21 | Infrared temperature measurement method based on response rate correction |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114878003A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117490859A (en) * | 2023-11-01 | 2024-02-02 | 中国航空工业集团公司北京长城计量测试技术研究所 | Ambient temperature compensation method and device for radiation thermometer |
-
2022
- 2022-03-21 CN CN202210278769.4A patent/CN114878003A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117490859A (en) * | 2023-11-01 | 2024-02-02 | 中国航空工业集团公司北京长城计量测试技术研究所 | Ambient temperature compensation method and device for radiation thermometer |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111351583A (en) | Temperature correction method for infrared temperature measurement and infrared thermal imager | |
| CN109655162A (en) | Thermal infrared imager temperature measurement correction system and method | |
| CN112393808B (en) | Temperature compensation method and system for thermal camera | |
| CN103528694B (en) | A kind of method of temperature of infrared heat image instrument measuring target object | |
| CN111307293B (en) | Infrared human body temperature measurement system and temperature measurement method thereof | |
| CN111780879B (en) | Infrared temperature measurement system and temperature measurement method | |
| CN106679817B (en) | A method of for Calibration of Infrared Thermal Imager | |
| US20010040216A1 (en) | Method and apparatus for correction of microbolometer output | |
| US20100289901A1 (en) | Thermographic camera | |
| CN113375815B (en) | Object surface temperature measuring method and system combining CCD and thermal infrared imager | |
| CN111024238A (en) | Radiation calibration and temperature measurement method for uncooled temperature measurement thermal imager | |
| CN111272290B (en) | Temperature measurement thermal infrared imager calibration method and device based on deep neural network | |
| CN111256835B (en) | Temperature measurement thermal infrared imager calibration method and device of hyper-parameter polynomial physical model | |
| US20160018266A1 (en) | Digital temperature determination using a radiometrically calibrated and a non-calibrated digital thermal imager | |
| TWI716229B (en) | High-precision non-contact temperature measuring device | |
| CN110361094B (en) | Non-uniformity correction method and device for staring type focal plane array | |
| CN114878003A (en) | Infrared temperature measurement method based on response rate correction | |
| CN111024237A (en) | Non-contact wide-temperature-difference infrared temperature measuring method | |
| US20240159594A1 (en) | Calibration mechanism for thermal imaging systems | |
| CN113984220B (en) | Differential blackbody radiation temperature difference correction method based on equivalent emissivity | |
| CN112611482A (en) | Method for calibrating temperature sensor of intelligent equipment | |
| CN106500856A (en) | A kind of adaptive correction method that thermal infrared imager scale function is applied to actual measuring environment | |
| US11543298B1 (en) | Temperature calibration method for a temperature measuring device | |
| US20230123056A1 (en) | Temperature measuring device having a temperature calibration function | |
| JP7318049B1 (en) | How to correct the temperature measurement of a black body under temperature fluctuations of the thermosensitive element |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |