Calibration system of infrared thermometer

Abstract

The utility model discloses a calibration system of an infrared thermometer, which is applied to an optical temperature measurement technology and comprises an infrared light source, a ray casting converter, an infrared detector and an information processor, the center of the infrared light source, the optical axis of the ray casting converter and the center of the infrared detector are aligned; wherein the infrared light source emits an infrared radiation signal to the light projection conversion device; the light ray projection conversion device is used for focusing and projecting the received infrared radiation signal or converting the received infrared radiation signal into parallel light rays and projecting the parallel light rays to the infrared detector, so that the optical lens is calibrated during clear imaging; and the infrared detector is used for receiving the infrared radiation signal and sending the infrared radiation signal to the information processor. According to the calibration system, the problem of low temperature measurement precision in the prior art can be solved, and the temperature measurement precision of the calibration system of the infrared thermometer can be effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of optical temperature measurement, and in particular to a calibration system for an infrared thermometer. Background Art

[0002] The infrared focal plane array is composed of hundreds of thousands or even millions of pixels, and the properties of each pixel are different. When forming an infrared temperature measurement system, in order to focus the infrared radiation signal radiated by external objects on the infrared focal plane array for imaging, it is necessary to add an optical lens outside the infrared focal plane array. However, the addition of the optical lens will make the infrared radiation signal intensity obtained by the pixels at different positions different, which requires the calibration of the infrared temperature measurement system.

[0003] When calibrating the infrared temperature measurement system, the relative illumination needs to be calibrated. Relative illumination refers to the ratio of the light intensity received by pixels at other positions compared to the central pixel. When calibrating related technologies, they are not within the clear imaging range of the optical lens, resulting in the relative illumination curve actually calibrated being different from the relative illumination curve during normal clear imaging. When used, the calibration of pixels at the edge positions will be over-compensated, which will have a certain impact on the imaging and temperature measurement effects.

[0004] In view of this, improving the temperature measurement accuracy of the infrared temperature measurement system is a technical problem that needs to be solved by technicians in the relevant field.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present application, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Utility Model Content

[0006] The present application provides a calibration system for an infrared thermometer, which can effectively improve the temperature measurement accuracy of the infrared temperature measurement system.

[0007] In order to solve the above technical problems, the embodiment of the utility model provides a calibration system of an infrared thermometer, comprising an infrared light source, a light projection converter, an infrared detector and an information processor; the center of the infrared light source, the optical axis of the light projection converter, and the center of the infrared detector are aligned;

[0008] Wherein, the infrared light source emits an infrared radiation signal to the light projection conversion device;

[0009] The light projection conversion device is used to focus and project the received infrared radiation signal or convert it into parallel light and project it to the infrared detector, so that the optical lens can be calibrated when the image is clear;

[0010] The infrared detector is used to receive infrared radiation signals and send the infrared radiation signals to the information processor.

[0011] Exemplarily, the infrared light source includes a first black body and a second black body, and the first black body and the second black body have different temperatures.

[0012] Exemplarily, it also includes a horizontally movable base;

[0013] The first black body and the second black body are placed on the horizontal movable base, and the spatial positions of the first black body and the second black body are adjusted during the movement of the horizontal movable base.

[0014] Exemplarily, the horizontal movable base includes a fixed base, a guide rail base, a guide rail, a first bearing platform and a second bearing platform;

[0015] The guide rail base is installed and fixed on the fixed base, and the guide rail is connected to the first bearing platform and the second bearing platform;

[0016] The guide rail base is provided with a slide groove, the side wall of the slide groove is provided with a limit pin, the guide rail is installed in the slide groove and slides along the extension direction of the slide groove.

[0017] Exemplarily, a vertical moving device is also included, and the infrared detector is mounted and fixed on the vertical moving device, and the spatial position is adjusted when the vertical moving device moves in the vertical direction.

[0018] Exemplarily, the vertical moving device is a lifting platform;

[0019] The lifting platform comprises a slot, and the infrared detector is fixed in the slot.

[0020] Exemplarily, a display for displaying a relative illumination curve and a temperature measurement image is also included.

[0021] Exemplarily, the infrared detector further includes a baffle switch

[0022] Exemplarily, the light projection converter is a collimator;

[0023] Wherein, the optical axis of the collimator objective lens, the center of the infrared light source and the center of the infrared detector are aligned.

[0024] Exemplarily, the light projection converter is a teleconverter;

[0025] Wherein, the optical axis of the teleconverter, the center of the infrared light source and the center of the infrared detector are aligned.

[0026] It can be seen from the above technical solution that the infrared light emitted by the infrared light source is focused and projected or transformed into parallel light and projected onto the infrared detector through the light projection conversion device. In this way, during the calibration process, it can be within the clear imaging range of the optical lens, so that the relative illumination during normal imaging can be calibrated, and the deviation of the relative illumination during calibration can be reduced, making the image effect clearer, making the non-uniformity correction effect better, reducing the temperature measurement differences of pixels at different positions of the product, and effectively improving the temperature measurement effect of the infrared temperature measurement system.

[0027] The technical features mentioned above, the technical features to be mentioned below, and the technical features shown separately in the drawings can be combined with each other arbitrarily, as long as the combined technical features are not contradictory. All feasible feature combinations are technical contents clearly recorded in this application. Any of the multiple sub-features contained in the same sentence can be applied independently, and does not have to be applied together with other sub-features.

[0028] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present utility model, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is a schematic diagram of the correction system structure in the related art;

[0031] Figure 2 A schematic structural diagram of an exemplary implementation of a calibration system for an infrared thermometer provided in an embodiment of the utility model;

[0032] Figure 3 A structural schematic diagram of another implementation of a calibration system for an infrared thermometer provided in an embodiment of the utility model;

[0033] Figure 4 A schematic diagram of a simplified optical path structure of a calibration system for an infrared thermometer provided in an embodiment of the utility model;

[0034] Figure 5 A schematic diagram of an optical path simulation layout of a calibration system of an infrared thermometer provided in an embodiment of the utility model;

[0035] Figure 6 Another schematic diagram of the optical path simulation layout of the calibration system of the infrared thermometer provided in the embodiment of the utility model;

[0036] Figure 7 A schematic diagram of another optical path simulation layout of the calibration system of the infrared thermometer provided in the embodiment of the utility model;

[0037] Figure 8 A schematic diagram of a relative illumination curve for close-range calibration provided by an embodiment of the utility model;

[0038] Fig. 9 A schematic diagram of a relative illumination curve with collimator calibration provided in an embodiment of the utility model;

[0039] Fig.10 A schematic diagram for comparing relative illumination curves provided in an embodiment of the utility model;

[0040] Fig.11 The embodiment of the utility model provides Fig.10 A magnified schematic diagram of the edge position;

[0041] Fig.12 A schematic diagram of a temperature measurement image after close-range calibration provided by an embodiment of the utility model;

[0042] Fig.13 A schematic diagram of another temperature measurement image after close-range calibration provided by an embodiment of the utility model;

[0043] Fig.14 A schematic diagram of a temperature measurement image after calibration of a collimator provided in an embodiment of the utility model;

[0044] Fig.15 A schematic diagram of another temperature measurement image after calibration of the collimator provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Among them, the terms "first", "second", "third", "fourth", etc. in the specification and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations of the two are intended to cover non-exclusive inclusions. The term "exemplary" means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments.

[0046] Any object with a temperature higher than absolute zero will emit infrared radiation energy. The higher the temperature of the object, the stronger the infrared radiation. The infrared thermometer gathers the infrared radiation energy of the object to be measured through its optical system, focuses it on the photodetector and converts it into a corresponding electrical signal. The signal is converted into the temperature value of the object to be measured after passing through the amplifier and signal processing circuit and correction according to the algorithm and target emissivity in the instrument. The infrared detector of the infrared thermometer is an infrared focal plane array integrated with hundreds of thousands or even millions of pixel units, which can present infrared images in real time. However, due to the non-uniformity of the optical device itself, the working state will also introduce non-uniformity. In addition, the influence of the optical system, such as the uneven distribution of radiation caused by the lens and the radiation of the lens barrel itself, will also cause obvious non-uniformity in the original output image of the infrared thermometer. Among them, the non-uniformity of the optical device itself refers to the defects and non-uniformity of the semiconductor materials used in the optical device, as well as the deviations in the process, which lead to different responses of each pixel. The non-uniformity introduced by the working state, such as the uneven temperature of the focal plane device, the change of the driving signal on the readout circuit, and the 1 / f noise introduced by the surface current of the semiconductor.

[0047] At present, infrared thermometers are calibrated before leaving the factory to correct the non-uniformity of the infrared thermometer. The correction method assumes that the response of the unit in the focal plane is linear, that is, Vij=kijQ+bij, where Q is the amount of radiation incident on each pixel, kij is the slope of the line, and bij is the intercept. In this way, as long as the response values ​​of high-temperature objects and low-temperature objects are collected for each pixel point, the relative values ​​of kij and bij for each pixel point can be calculated, thereby correcting the response rate and offset. When calibrating the product, the relative illumination deviation caused by the optical lens needs to be calibrated, such as Figure 1 As shown, the calibration system of the related art includes a uniform plate 10, a calibrated product 11, a mounting and fixing platform 12, and an information processing platform 13. The two-point calibration is performed by placing the lens close to the uniform plate 10, and the distance between the lens and the uniform plate 10 is about 3 cm. During calibration, data acquisition is required for the uniform plate 10, but the area of ​​the uniform plate 10 is not large enough, so it can only be calibrated at a close distance, and the close distance is not within the clear imaging range of the optical lens. Whether the imaging is clear will affect the relative illumination; moreover, when the uniform plate 10 is very close to the detector, the structure of the lens itself and the detector structure will be projected onto the infrared focal plane, which will affect the K value data finally calibrated. The K value data contains the shape of the relative illumination curve, which affects the effect of non-uniformity correction. In the case of poor uniformity, the temperature measurement difference of pixels at different positions will become larger.

[0048] In view of this, the utility model can calibrate the product when the lens is clearly imaging through a light projection converter, can calibrate the relative illumination during normal imaging, and reduce the impact of the lens structure. After introducing the technical solution of the utility model, various non-limiting implementation methods of the utility model are described in detail below. In order to better illustrate the utility model, numerous specific details are given in the specific implementation methods below. Those skilled in the art should understand that the utility model can also be implemented without these specific details. In other examples, methods, means, components and circuits well known to technicians in the relevant field are not described in detail in order to highlight the main purpose of the utility model.

[0049] First, see Figure 2 , Figure 2 This is a schematic diagram of a structure of an implementation of a calibration system for an infrared thermometer provided in this embodiment. The calibration system for an infrared thermometer in this embodiment may include the following contents:

[0050] The calibration system of the infrared thermometer may include an infrared light source 21, a light projection converter 22, an infrared detector 23 and an information processor 24. The center of the infrared light source 21, the optical axis of the light projection converter 22 and the center of the infrared detector 23 are aligned.

[0051] Among them, the infrared light source 21 can be any object that can radiate infrared signals, which is used to emit infrared radiation signals to the light projection conversion device 2. The light projection conversion device 2 is used to focus and project the received infrared radiation signals to the infrared detector. Since a focusing and projection process is performed, the optical lens can be clearly imaged. The light projection conversion device 2 can also convert the received infrared radiation signal into parallel light and project it to the infrared detector. The parallel light is equivalent to infinitely magnifying the uniform plate, which can also make the lens clearly imaged, and will not be affected by the structure of the lens itself or other structures of the infrared detector. In this way, the infrared thermometer can be calibrated within the clear imaging range of the optical lens. The infrared detector 23 is used to receive infrared radiation signals and convert the infrared radiation signals into electrical signals and send them to the information processor 24. The information processor 24 can power the infrared detector 23 and communicate with the infrared detector 23. At the same time, any calibration method recorded in the relevant technology is used to perform corresponding data acquisition and data processing. This embodiment does not impose any restrictions on the data acquisition and data processing of the information processor 24.

[0052] In the technical solution provided in this embodiment, the infrared light emitted by the infrared light source is focused and projected or transformed into parallel light and projected onto the infrared detector through a light projection conversion device. In this way, during the calibration process, it can be within the clear imaging range of the optical lens, so that the relative illumination during normal imaging can be calibrated, and the deviation influence of the relative illumination during calibration can be reduced, making the image effect clearer, making the non-uniformity correction effect better, reducing the temperature measurement difference of pixels at different positions of the product, and effectively improving the temperature measurement effect of the infrared temperature measurement system.

[0053] Exemplarily, this embodiment also provides an exemplary implementation structure of the infrared light source 21. The infrared light source 21 of this embodiment may include a first black body and a second black body, and the first black body and the second black body have different temperatures. By using two black bodies with different temperatures, the infrared thermometer can be calibrated more conveniently and quickly.

[0054] In order to further improve the calibration efficiency, two black bodies can be placed on a horizontal moving base, that is, the system also includes a horizontal moving base, the first black body and the second black body are placed on the horizontal moving base, and the first black body and the second black body adjust their spatial positions during the movement of the horizontal moving base. In this way, the two black bodies can move freely in the horizontal direction, quickly adjust the optical path system, and avoid the tedious steps of disassembling and replacing the infrared light source.

[0055] In order to prevent the vibration generated during the movement from affecting the stability of the optical path and other optical components, the present embodiment also provides an exemplary structure of a horizontal movable base, which may include the following contents: the horizontal movable base includes a fixed base, a guide rail base, a guide rail, a first bearing platform and a second bearing platform; the guide rail base is installed and fixed on the fixed base, the guide rail is connected to the first bearing platform and the second bearing platform, the first bearing platform is used to carry the first black body, the second bearing platform is used to carry the second black body, the guide rail base is provided with a slide groove, the side wall of the slide groove is provided with a limit pin, the guide rail is installed in the slide groove, and slides along the extension direction of the slide groove. In this way, during the sliding process of the first bearing platform and the second bearing platform installed on the guide rail along the extension direction of the slide groove on the guide rail base, the vibration can be transmitted to the guide rail through the limit pin, so as to prevent the vibration from being directly transmitted to the guide rail and causing damage to the guide rail, and at the same time, it can prevent the vibration from affecting the use and reliability of the first bearing platform and the second bearing platform and the optical devices thereon.

[0056] In order to further improve the convenience of adjusting the optical path, based on the above embodiment, the calibration system of the infrared thermometer may further include a vertical moving device, the infrared detector 23 is mounted and fixed on the vertical moving device, and the spatial position is adjusted during the vertical movement of the vertical moving device. In this embodiment, the vertical moving device at least has the function of moving up and down in the vertical direction and can fix the infrared detector 23, thereby driving the infrared detector 23 to move up and down. Exemplarily, the vertical moving device may be a lifting platform, the lifting platform includes a slot, and the infrared detector 23 is fixed in the slot.

[0057] In order to further improve the user experience, the calibration system of the infrared thermometer may further include a display, which may be used to display the relative illumination curve and the temperature measurement image.

[0058] In order to further improve the user experience and to adapt to temperature measurement defects, the infrared detector 23 may also include a baffle switch. The baffle may be built between the infrared detector 23 and the optical lens. When it is necessary to reset the detector parameters and / or calibrate the image, the opening and closing of the baffle may be adjusted automatically or manually.

[0059] The above embodiment does not limit the light projection converter 2. This embodiment provides two parallel implementation methods. Exemplarily, the light projection converter 2 can use a teleconverter. Accordingly, the optical axis of the teleconverter, the center of the infrared light source 1 and the center of the infrared detector 3 are aligned. Exemplarily, the light projection converter 2 can also use a collimator. The optical axis of the collimator objective lens, the center of the infrared light source 1 and the center of the infrared detector 3 are aligned. By changing the light into parallel light, it is equivalent to changing the uniform plate to infinity. A collimator is added between the uniform plate and the product. The light is first adjusted to parallel light and then incident on the product lens. The relative illumination during normal imaging can be calibrated, so that the non-uniformity correction effect is better, which will reduce the temperature measurement difference of pixels at different positions of the product.

[0060] In order to verify the effectiveness of this technical solution, this embodiment also provides an exemplary infrared thermometer calibration system, see Figure 3 , which may include the following:

[0061] The calibration system of the infrared thermometer may include a first black body 211, a second black body 212, a horizontally movable base 213, a collimator 220, a bracket 221, an infrared detector 23, a lifting platform 230, and an information processor 24 with a display screen. The first black body 211 and the second black body 212 have different temperatures and can be translated forward and backward; the collimator 220 is fixed on the bracket 221, and the optical axis of the objective lens, the center of the black body facing it, and the center of the infrared detector are aligned; the infrared detector 23 is fixed in the card slot of the lifting platform 230 and can move up and down. The information processor 24 supplies power to the infrared detector 23 and performs data acquisition and data processing.

[0062] Use optical simulation software such as Zemax to calibrate the optical path of the infrared thermometer system, such as Figure 4 As shown, the simulation is performed and the simulation results are shown in Figures 5 to 7 Based on the above optical system, a 256*192 focal plane array, a 3.2mm focal length and a lens with an F number of 1.1 were used for testing. Without adding a collimator, calibration was performed at a close distance, that is, 3cm between the lens and the uniform plate. The relative illumination curve obtained is shown in the figure below. Figure 8 As shown in Figure 2, after adding parallel light tubes for calibration, the relative illumination curve is as follows: Fig. 9 As shown, the two calibration values ​​are compared, that is, the K value of the collimator is divided by the K value at close distance, and the comparison result is as follows Fig.10 As shown, Fig.11 The curve from the edge to the center is intercepted. The curve fluctuations include the difference between pixels and the fluctuation of the collected data. It can be seen that at the edge, after adding the collimator, the relative illumination curve has been significantly improved. Further, using 30℃ black body and 80℃ black body as infrared light sources, the focal length of the lens is 3.2mm, the F number is 1.1, and the product distance is 1m for temperature measurement.

[0063] Use the K value calibrated at a close distance (i.e. 3cm) to measure the temperature. The temperature measurement results are as follows Fig.12 and Fig.13 As shown in the figure, non-uniform deviation occurs at the corners, and the temperature measurement range is 1.84℃ and 3.88℃ respectively. This is caused by the calibrated relative illumination curve not being applicable at the edge. When the K value calibrated by adding a parallel light tube is used for temperature measurement, the temperature measurement results are as follows Fig.14 and Fig.15 As shown in the figure, the temperature measurement range is 0.8℃ and 0.84℃ respectively. It can be seen that the K value calibrated by the collimator can significantly reduce the difference in temperature measurement non-uniformity when measuring temperature in real usage scenarios.

[0064] The above is a detailed introduction to the calibration system of an infrared thermometer provided by the utility model. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the utility model, the utility model can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the utility model.

Claims

1. A calibration system for an infrared thermometer, characterized in that: It includes an infrared light source, a light projection converter, an infrared detector and an information processor; the center of the infrared light source, the optical axis of the light projection converter and the center of the infrared detector are aligned; Wherein, the infrared light source emits an infrared radiation signal to the light projection conversion device; The light projection conversion device is used to focus and project the received infrared radiation signal or convert it into parallel light and project it to the infrared detector, so that the optical lens can be calibrated when the image is clear; The infrared detector is used to receive infrared radiation signals and send the infrared radiation signals to the information processor.

2. The calibration system of the infrared thermometer according to claim 1, characterized in that: The infrared light source includes a first black body and a second black body, and the first black body and the second black body have different temperatures.

3. The calibration system of the infrared thermometer according to claim 2, characterized in that: Also included is a horizontally movable base; The first black body and the second black body are placed on the horizontal movable base, and the spatial positions of the first black body and the second black body are adjusted during the movement of the horizontal movable base.

4. The calibration system of the infrared thermometer according to claim 3, characterized in that: The horizontal movable base comprises a fixed base, a guide rail base, a guide rail, a first bearing platform and a second bearing platform; The guide rail base is installed and fixed on the fixed base, and the guide rail is connected to the first bearing platform and the second bearing platform; The guide rail base is provided with a slide groove, the side wall of the slide groove is provided with a limit pin, the guide rail is installed in the slide groove and slides along the extension direction of the slide groove.

5. The calibration system of the infrared thermometer according to claim 1, characterized in that: It also includes a vertical moving device, the infrared detector is installed and fixed on the vertical moving device, and adjusts the spatial position during the vertical moving device moving in the vertical direction.

6. The calibration system of the infrared thermometer according to claim 5, characterized in that: The vertical moving device is a lifting platform; The lifting platform comprises a slot, and the infrared detector is fixed in the slot.

7. The calibration system of the infrared thermometer according to claim 1, characterized in that: A display for displaying relative illumination curves and temperature measurement images is also included.

8. The calibration system of the infrared thermometer according to claim 1, characterized in that: The infrared detector also includes a baffle switch.

9. The calibration system of an infrared thermometer according to any one of claims 1 to 8, characterized in that: The light projection converter is a collimator; Wherein, the optical axis of the collimator objective lens, the center of the infrared light source and the center of the infrared detector are aligned.

10. The calibration system of an infrared thermometer according to any one of claims 1 to 8, characterized in that: The light projection converter is a teleconverter; Wherein, the optical axis of the teleconverter, the center of the infrared light source and the center of the infrared detector are aligned.

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