Non-contact visual temperature measuring device

Abstract

The utility model relates to temperature measuring device technical field discloses a kind of non-contact visual temperature measuring device, including coaxially arranged shell and inner shell, inner shell is located in shell, and inner shell is equipped with plasma generator, and one end of inner shell is equipped with gas source, and other end is equipped with outlet, cavity is formed between shell and inner shell, two infrared temperature sensors are equipped at the outlet of cavity, two infrared temperature sensors are symmetrically arranged at the two sides of cavity, two infrared temperature sensors are oppositely inclined, the included angle of optical axis of infrared temperature sensor and horizontal plane is α, 15 °≤α≤25 °. Can be in the treatment process to human skin temperature fast measurement, effectively prevent skin scald. The visual temperature measuring device can be applied to other close-range non-contact human skin temperature measurement application scenarios that cannot be installed to the center of temperature measuring head, improve the use range, reduce use cost.

Description

Technical Field

[0001] This utility model relates to the field of temperature measurement device technology, specifically to a non-contact visual temperature measurement device. Background Technology

[0002] The infrared temperature sensor used for temperature measurement operates on the principle of the pyroelectric effect, converting the infrared radiation from the human body or other objects into an electrical signal, which is then calculated to determine the object's surface temperature. Conventional non-contact human body temperature measurement solutions typically place the infrared temperature sensor at the center of the measuring head, with a small field of view, suitable for single-point (small-area) sampling of the skin surface. However, when applied to plasma therapy devices, because it involves surface irradiation, all points within the irradiated surface must meet the requirement of not exceeding the skin's maximum tolerable temperature of 41°C. Therefore, an infrared temperature sensor with a large field of view is needed, suitable for temperature acquisition and measurement within a certain area at close range. Furthermore, since the plasma therapy device's outlet center is the treatment area, and the jet is formed and emitted outwards through the central space, such as... Figure 3 As shown, if the temperature sensor is installed in the center, it will block the plasma jet and reduce the treatment effect. At the same time, the sensor is also affected by the high temperature at the outlet, which makes it impossible to guarantee the accuracy of temperature measurement. Utility Model Content

[0003] This invention addresses the existing technical problems by providing a non-contact visual temperature measurement device.

[0004] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A non-contact visual temperature measurement device includes a coaxially arranged outer shell and an inner shell. The inner shell is located inside the outer shell and is equipped with a plasma generator. One end of the inner shell is equipped with a gas source and the other end is equipped with an outlet. A cavity is formed between the outer shell and the inner shell. Two infrared temperature sensors are provided at the outlet of the cavity. The two infrared temperature sensors are symmetrically arranged on both sides of the cavity and are inclined relative to each other. The angle between the optical axis of the infrared temperature sensor and the horizontal plane is α, where 15°≤α≤25°.

[0005] Based on the above technical solution, the present invention can be further improved as follows:

[0006] Preferably, the inner shell has multiple air guide holes on its side wall, the air guide holes are located at the end near the air source and are connected to the cavity, and the outer shell has multiple air outlet holes on its side wall, the air outlet holes are located at the end near the outlet.

[0007] Preferably, the cavity includes a first guide section, a second guide section, and a third guide section arranged sequentially. The first guide section is connected to the air guide hole, and the second guide section is in the shape of a trumpet with a gradually increasing opening.

[0008] Preferably, a laser rangefinder is also installed at the outlet of the cavity.

[0009] Preferably, the plasma generator includes an anode and a cathode, with an insulating air ring between the anode and the cathode, an insulating flow guide block installed on the outside of the anode, the insulating flow guide block being installed on a support plate inside the inner shell, and the support plate having air blowing holes.

[0010] Preferably, the distance between the outlet and the object to be tested is 1cm-10cm.

[0011] The beneficial effects of this invention are as follows: by installing infrared temperature sensors on both sides of the cavity outlet, the plasma jet is not affected, ensuring the therapeutic effect. Furthermore, the influence of high temperatures on the infrared temperature sensors is avoided, guaranteeing measurement accuracy. By rapidly measuring human skin temperature during treatment, skin burns are effectively prevented. This visual temperature measurement device can be applied to other short-range, non-contact human skin temperature measurement scenarios where it is impossible to install the sensor at the exact center of the temperature head, thus expanding its application range and reducing operating costs. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the visual temperature measurement device of this utility model;

[0013] Figure 2 This is a schematic diagram showing the installation of the infrared temperature sensor of this utility model.

[0014] Figure 3 This is a schematic diagram of a visual temperature measurement device in the prior art.

[0015] The attached diagram is labeled as follows: 1. Outer shell; 2. Inner shell; 3. Insulating guide block; 4. Insulating air ring; 5. Anode; 6. Cathode; 7. Cavity; 8. Infrared temperature sensor; 9. Air guide hole; 10. Laser rangefinder sensor; 11. Air outlet; 12. Object to be measured; 13. Air blowing hole. Detailed Implementation

[0016] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0017] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model.

[0018] like Figure 1 and Figure 2 As shown, this utility model discloses a non-contact visual temperature measurement device, including a coaxially arranged outer shell 1 and an inner shell 2. The inner shell 2 is located inside the outer shell 1 and contains a plasma generator. One end of the inner shell 2 has a gas source, and the other end has an outlet. A cavity 7 is formed between the outer shell 1 and the inner shell 2. The cavity 7 is annular, and two infrared temperature sensors 8 are provided at the outlet of the cavity 7. The two infrared temperature sensors 8 are symmetrically arranged on both sides of the cavity 7 to ensure sufficient and unobstructed passage space for the central plasma jet area, thus ensuring the treatment effect. The two infrared temperature sensors 8 are inclined relative to each other, and the angle between the optical axis of the infrared temperature sensor 8 and the horizontal plane is α, where 15°≤α≤25°. This ensures that within the effective treatment area, as the object to be measured 12 moves, the temperature measurement range remains within the imaging area of ​​the infrared temperature sensor 8. In this embodiment, the object to be measured 12 is human skin, and the effective treatment area is the range of 1cm-10cm between the outlet and the object to be measured 12. This ensures that within the treatment distance, the target imaging point falls more often in the area with higher image plane sampling accuracy. At the same time, through a complementary approach, it can ensure that when the human body is tilted to one side, the temperature points obtained by binocular measurement can be used for mutual calibration after image registration, and the temperature of the jet irradiation area can still be sampled.

[0019] In this embodiment, the distance between the two infrared temperature sensors 8 is B, and the angle between the optical axes of the two infrared temperature sensors 8 is θ. This angle determines the effective temperature measurement distance; the larger the angle, the smaller the temperature measurement distance, and vice versa. In this embodiment, the angle θ is 25°, and the optical center distance B is 128mm. P represents the relative position of the object 12 to be measured, and its distance to the outlet of the inner shell 2 should be between 1cm and 10cm to ensure that the object to be measured is within the optical field of view of the two infrared temperature sensors 8. See [link to relevant documentation]. Figure 2 As shown.

[0020] The inner shell 2 has multiple air guide holes 9 on its side wall, located near the air source and communicating with the cavity 7. The outer shell 1 has multiple air outlet holes 11 on its side wall, located near the outlet. Air flows into the cavity 7 through the air guide holes 9 and out through the air outlet holes 11, thus cooling the infrared temperature sensor 8, ensuring its measurement accuracy, and extending its service life.

[0021] The cavity 7 includes a first guide section, a second guide section, and a third guide section arranged sequentially. The first guide section is connected to the air guide hole 9, the second guide section is in the shape of a trumpet with a gradually increasing opening, and the third guide section is connected to the air outlet 11. By setting multiple connected guide sections, the cooling airflow is evenly distributed, avoiding the problem of measurement drift or image jitter of the infrared temperature sensor 8 caused by airflow disturbance. This achieves both cooling of the infrared temperature sensor 8 and ensures the measurement accuracy of the infrared temperature sensor 8.

[0022] Furthermore, a laser rangefinder 10 is installed at the outlet of the cavity 7 to measure the distance between the object to be tested 12 and the outlet, ensuring that the object to be tested 12 is within the effective treatment area.

[0023] The plasma generator includes an anode 5 and a cathode 6, with an insulating air ring 4 between the anode 5 and the cathode 6. An insulating guide block 3 is installed on the outside of the anode 5, and the insulating guide block 3 is mounted on a support plate inside the inner shell 2. The support plate has air blowing holes 13. Working gas is introduced through the air blowing holes 13, and a voltage is applied between the anode 5 and the cathode 6. The gas is ionized to form a plasma gas flow, which is ejected through the outlet and acts on the surface of the target object to achieve a therapeutic effect.

[0024] The working process of this non-contact visual temperature measurement device is as follows:

[0025] S1: Image preprocessing and contour extraction, extracting the contour of the target region from the original infrared image;

[0026] Specifically, this includes preprocessing the infrared image, which includes threshold segmentation, morphological processing (dilation, erosion), image smoothing (smoothing filtering), and edge enhancement (Laplacian detection).

[0027] Specifically, threshold segmentation: binarize the original infrared image and extract the high-temperature region;

[0028] Dilation operation: fills holes in the target region and improves image connectivity;

[0029] Image smoothing: Use median filtering or Gaussian filtering to reduce noise;

[0030] Laplacian edge detection: Extracting target edge information;

[0031] Contour extraction: Obtain the boundary of the target region;

[0032] ROI boundary calculation and effective temperature measurement point statistics: Determine the region of interest and count the number of effective temperature points within it.

[0033] Since the thermal plasma heat source is active radiation in a fixed direction, the energy is mainly concentrated along the axis of the exit path. Therefore, after the target surface is irradiated, the central temperature is relatively high and uniform within the region, forming a significant temperature difference with the surrounding area. From the frequency domain perspective, the target area only has high-frequency information at the edges, while the central area often has low-frequency information (the grayscale changes in infrared images are relatively flat). Therefore, the central area of ​​the image obtained by infrared measurement should be approximately connected. The dilation algorithm can effectively fill the holes generated after thresholding, increasing the connectivity of the image. Then, edge calculation is performed after filtering and smoothing and the Laplacian algorithm to calculate the position of the target edge points. The Laplacian operator is an isotropic (rotationally axisymmetric) edge detection operator that is independent of direction and is very sensitive to noise. Therefore, the image must be smoothed before edge detection.

[0034] Preprocessing images can enhance image quality, remove noise interference, improve target recognition accuracy, and provide clear boundaries for subsequent registration.

[0035] S2: Image registration. Based on the target area image, the two images are aligned spatially to ensure that temperature points can be compared and fused in the same coordinate system. The two images refer to the two images formed after extracting the target area from the original infrared image data collected by the two infrared temperature sensors 8. Because there are two infrared temperature sensors 8, two infrared image data will be collected in the same acquisition.

[0036] Since the discharge zone of the plasma generator is in the center, the heat decreases radially, and the temperature distribution shown in the thermal map is centrally symmetrical, the classic ICP algorithm is used here. The centroid of the image is used as the feature point to complete the point set registration of the binocular image, ensuring the spatial consistency of the binocular image, ensuring the comparability of temperature points, eliminating the temperature measurement deviation caused by visual differences, and supporting stable image matching in dynamic scenes.

[0037] To verify the accuracy of the algorithm, a blackbody was used as the target object and tested close to the treatment outlet end face. The temperature data obtained by the infrared temperature sensor 8 was read. The above work can only ensure that the raw data of the infrared temperature sensor 8 is used correctly and effectively. The data points obtained by collecting the temperature can effectively reflect the true temperature of the object 12 and the accuracy is qualified. However, it cannot eliminate the measurement error. According to previous research, the measurement error of the infrared temperature sensor 8 is affected by the emissivity of the object surface, the measurement distance and the ambient temperature. The accuracy of the infrared temperature sensor 8 largely depends on calibration.

[0038] S3: Temperature point selection and weighted calculation; calculate the objective function and iteratively find the parameter combination that maximizes the value. The objective function is a weighted temperature estimation model, specifically:

[0039] , To screen temperatures, Represents a high-precision temperature point. This represents a low-precision temperature point.

[0040] Due to the inherent characteristics of the infrared temperature sensor 8, the temperature measurement accuracy varies across different areas of the image. The accuracy is higher at the center (±1℃) and slightly lower around the perimeter (±1.5℃). To ensure the final measurement accuracy, the algorithm assigns an influence factor based on the coordinates of the temperature measurement points. Screening temperature for: Among them, screening temperature This is a calculated weighted fusion temperature value, used to reflect the overall temperature of the target area; that is, the output fusion temperature value. Represents a high-precision temperature point. This represents a low-precision temperature point. The formula can be understood as follows: points with higher precision have a higher influence factor, while points with lower precision have a lower influence factor. This allows the final temperature calculation to primarily utilize points with higher precision. When image quality is poor or the image is too far off-center, it becomes necessary to introduce lower-precision points. The higher-precision temperature points will be prioritized based on their influence factors, thus reducing the impact of lower-precision points and ensuring the accuracy of infrared temperature measurement points.

[0041] By introducing an influence factor mechanism, the central region has high precision and the edge region has low weight. When the image shifts or quality deteriorates, the influence of low precision points is automatically reduced. By using objective function and parameter optimization strategy, the optimal weight configuration is achieved, thereby significantly improving the temperature measurement stability and reliability under complex conditions.

[0042] This step involves inputting the infrared image data of the current frame, calculating the weighted average temperature using an objective function, achieving the optimal temperature estimate for the current frame, and then outputting the fused temperature value of the current frame.

[0043] S4: Error compensation and temperature correction; error compensation includes ambient temperature compensation and distance compensation.

[0044] Regarding ambient temperature compensation: The infrared temperature sensor 8 is housed inside the outer casing 1. Due to the high radiation temperature from the heat source at the outlet (generally 50℃~70℃), the infrared temperature sensor 8 may malfunction or experience reduced temperature measurement accuracy under these operating ambient temperatures. Therefore, the infrared temperature sensor 8 is mounted on the cavity 7. After entering the generator, the gas source splits into two airflows. One airflow enters the cavity 7 and passes through the surface of the infrared temperature sensor 8, cooling its surface before diffusing to the outside of the outer casing 1, ensuring that the infrared temperature sensor 8 operates within the normal temperature range and is less affected by the heat source. The other airflow enters between the cathode 6 and the anode 5, participates in the discharge process, and blows out the generated plasma to form a plasma gas flow. Simultaneously, due to the directional flow of gas within the cavity 7, thermal equilibrium can be achieved quickly. Setting the operating temperature measurement point within this area provides a more accurate reflection of the ambient temperature, and the subsequent infrared temperature measurement algorithm module in the visual temperature measurement device also performs well after compensation.

[0045] Regarding distance compensation: To obtain accurate distance, a laser rangefinder 10 is installed at the exit of cavity 7 to measure the distance between the infrared sensor and the temperature measuring surface. ,in For the corrected temperature value, This is the original temperature value. This is the distance coefficient. The ambient temperature deviation is compensated for. The infrared temperature measurement error caused by the distance is compensated for, and the temperature is obtained after compensation. By compensating for the infrared temperature measurement error caused by the distance and the ambient temperature deviation, and compensating for each, the compensated target temperature is obtained, thus accurately reflecting the temperature of the object 12 being measured, improving the authenticity and consistency of the temperature measurement results.

[0046] S5: Algorithm optimization and verification, calculating the objective function and finding the parameter combination that maximizes the value through iterative steps;

[0047] Calculate the image boundary and count the number of valid temperature measurement points within the boundary, then set an error deviation. A decay operator ,according to , Calculate the objective function , By continuously iterating to obtain When taking the maximum value ( , ), at this time , The optimal parameters are used to obtain different temperature point sets at different target distances, satisfying the trade-off between the size of the calculation point set and the accuracy of the values. By continuously iterating and optimizing the objective function, the algorithm's adaptive capability is improved.

[0048] This step involves inputting multiple sets of standard sample data, evaluating the stability of the parameters through an objective function, optimizing and verifying the overall algorithm, and outputting the optimal parameter combination to ensure the system maintains high-precision temperature measurement.

[0049] S6: Outputs the compensated temperature image or temperature data. It provides an intuitive temperature image for easy viewing of the measurement results.

[0050] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A non-contact visual temperature measuring device, characterized by, The device includes a coaxially arranged outer shell (1) and an inner shell (2). The inner shell (2) is located inside the outer shell (1). A plasma generator is provided inside the inner shell (2). One end of the inner shell (2) is provided with a gas source, and the other end is provided with an outlet. A cavity (7) is formed between the outer shell (1) and the inner shell (2). Two infrared temperature sensors (8) are provided at the outlet of the cavity (7). The two infrared temperature sensors (8) are symmetrically arranged on both sides of the cavity (7). The two infrared temperature sensors (8) are arranged at an angle relative to each other. The angle between the optical axis of the infrared temperature sensor (8) and the horizontal plane is α, where 15°≤α≤25°.

2. The non-contact visual temperature measurement device according to claim 1, characterized in that, The inner shell (2) has multiple air guide holes (9) on its side wall. The air guide holes (9) are located at the end near the air source and are connected to the cavity (7). The outer shell (1) has multiple air outlet holes (11) on its side wall. The air outlet holes (11) are located at the end near the outlet.

3. The non-contact visual thermometry device of claim 2, wherein, The cavity (7) includes a first guide section, a second guide section and a third guide section arranged in sequence. The first guide section is connected to the air guide hole (9), and the second guide section is in the shape of a trumpet with a gradually increasing opening.

4. The non-contact visual thermometry device of claim 1 or 3, wherein, A laser rangefinder (10) is also installed at the outlet of the cavity (7).

5. The non-contact visual thermometry device of claim 4, wherein, The plasma generator includes an anode (5) and a cathode (6). An insulating air ring (4) is provided between the anode (5) and the cathode (6). An insulating guide block (3) is installed on the outside of the anode (5). The insulating guide block (3) is installed on a support plate inside the inner shell (2). The support plate is provided with air blowing holes (13).

6. The non-contact visual thermometry device of claim 1, wherein, The distance between the outlet and the object to be tested (12) is 1cm-10cm.

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