Automatic inspection method for batch high and low temperature working test of thermal imager

Abstract

The invention discloses a thermal imager batch high and low temperature working test automatic inspection method, and relates to thermal imager inspection. The automatic inspection device comprises a high and low temperature test box, a heating module, a collimator, a parallel guide rail, a thermal imager bracket, a hard disk video recorder, a video acquisition module, a serial port server and a power supply control board. The parallel guide rail is designed to drive the collimator to move in the high-low temperature test box, the problem that personnel need to enter the high-low temperature test box for operation is avoided, and the thermal imager output video is recorded and collected in real time by controlling the temperature setting in the high-low temperature test box, the movement of the parallel guide rail and the communication of the thermal imager. Whether the thermal imager responds to the sent communication instruction is judged through the image processing module, and the power supply of the abnormal thermal imager is cut off in time, so that the thermal imager is prevented from being damaged; inspection personnel do not need to participate in the whole inspection process, and the working intensity of the personnel is reduced.

Description

Technical Field

[0001] The invention relates to thermal imager inspection, and in particular to an automatic inspection method for batch high and low temperature working tests of thermal imagers, which does not require personnel participation in the operation process, reduces personnel workload, and improves efficiency. Background Art

[0002] In actual applications, thermal imagers may face various extreme temperature environments, such as hot deserts, cold polar regions, etc. Therefore, it is necessary to complete the high and low temperature test of thermal imagers in the factory inspection test to check whether the thermal imagers meet the requirements of the specifications. The high and low temperature test of thermal imagers is to place the thermal imagers in specific high and low temperature environments to test their product performance under different temperature conditions.

[0003] The existing high and low temperature test inspection method of thermal imagers requires people to enter the high and low temperature test box under high and low temperature environments, move the thermal imager to align with the collimator, and then operate the product to perform functional performance tests. During the high and low temperature test, people choose the opportunity to enter the high and low temperature test box according to the above operation, which is inefficient and increases the workload of inspectors.

[0004] Invention patent CN114518501A proposes a high and low temperature working and stress screening detection device for infrared detector components. This invention is a high and low temperature working detection method for infrared detector components. Since the infrared detector component is the core component of the thermal imager, there is a big difference between the detection technology of the detector and the detection technology of the thermal imager. Therefore, it is necessary to design and develop a special high and low temperature working test method based on the characteristics of the thermal imager. Summary of the invention

[0005] The present invention aims to solve the problem that the existing thermal imager inspection process relies on manual operation, is difficult, and cannot inspect the characteristics of the thermal imager. It provides an automatic inspection method for batch high and low temperature working tests of thermal imagers that does not require human participation in the operation process, reduces human workload, and improves efficiency.

[0006] The invention discloses an automatic inspection method for batch high and low temperature working tests of thermal imagers, characterized in that the inspection method is applied to an automatic inspection device, which comprises a high and low temperature test box, a heating module, a collimator, parallel guide rails, a thermal imager bracket, a hard disk recorder, a video acquisition module, a serial port server and a power control board. The high and low temperature test box is a hollow box, the parallel guide rails and the thermal imager bracket are arranged in parallel in the high and low temperature test box, and the thermal imager to be inspected is installed on the thermal imager bracket; the collimator is installed on the parallel guide rails and slides along the parallel guide rails, the light emitting aperture of the collimator is at the same height as the optical window of the thermal imager to be inspected, and the heating module is installed at the target position of the collimator; the video signal of the thermal imager to be inspected is respectively connected to the hard disk recorder and the video acquisition module, the communication, control and fire control signals of the thermal imager to be inspected are connected to the serial port server, the video acquisition module is connected to the serial port server, the power supply of the thermal imager to be inspected is connected to the power control board, and the high and low temperature test box, the heating module, the parallel guide rails and the power control board are respectively connected to the serial port server.

[0007] The high and low temperature test chamber provides different ambient temperatures for the thermal imager to be tested. The serial port server controls the power on and off, temperature setting, insulation time and temperature change rate of the high and low temperature test chamber; the heating module provides a radiation source for the thermal imager; when the temperature is higher than the set value, the heating module stops heating; the moving step interval of the parallel guide rail is the center interval of the thermal imager bracket; the power control board provides power to the thermal imager, sets the voltage, and provides abnormal protection for voltage and current; the hard disk recorder saves the video image of the high and low temperature test process of the thermal imager; the video acquisition module acquires the output image of the thermal imager to be tested in real time; after the current thermal imager video image is detected to be normal, the video acquisition module switches to the video channel of the next thermal imager.

[0008] The specific inspection steps are as follows: Step 1: Set the test parameters, including test temperature, test humidity, holding time, continuous working time of the thermal imager, reheating temperature and reheating holding time. The heating module, parallel guide rails and the thermal imager to be tested in the high and low temperature test chamber start working according to the parameters; Step 2: The high and low temperature test chamber is heated to the set temperature according to the temperature parameters; Step 3: After the temperature in the high and low temperature test chamber reaches the standard, it enters the insulation state, and the thermal imager to be tested is kept in the high and low temperature test chamber until thermal equilibrium is reached; Step 4: After the thermal imager to be inspected has reached its holding time, start the thermal imager to be inspected, and simultaneously turn on the image detection function and the timing function; Step 5: When the image to be tested enters the normal working state, the timing stops, and this moment is the start time. During the working period of the thermal imager to be tested, the voltage and current of the thermal imager are detected and recorded to monitor the power consumption; Step 6: Use a hard disk recorder to record the entire inspection process of the thermal imager to be inspected; Step 7: Collect and judge whether the image of the thermal imager to be inspected is normal through real-time or scheduled acquisition; if there is a flower screen, ink painting, flickering screen, poor uniformity or bright line, it is judged that the image of the thermal imager is abnormal, otherwise it is normal; Step 8: Turn on the heating module and set a suitable temperature difference to provide a heat source for the target; Step 9: The moving mechanism on the parallel rail drives the collimator to move through the parallel rail, so that the collimator is aligned with the large objective lens of the thermal imager to be inspected; according to the inspection items specified in the specification, the thermal imager to be inspected is inspected item by item. The inspection items and methods are as follows: a) Field of view switching time detection: The video acquisition module continuously acquires the image signal of the thermal imager to be inspected and records the time of acquiring the current frame. After the field of view switching is completed, the similarity of adjacent frames of the acquired images is compared and analyzed one by one. The time when the similarity starts to deteriorate is recorded as the field of view switching start time T1, and the time when the similarity becomes high again is recorded as the field of view switching completion time T2. The switching time Dt=T2-T1; b) Thermal imager focus function test: adjust the focal length of the thermal imager to be tested, first change the focus value to the minimum, then the focus division value to 1, and adjust the focus plane to the maximum value in the positive direction in sequence, and collect thermal images in sequence at each focus plane value state. After the adjustment is completed, analyze the clarity of the collected images. When the clarity of the collected target image changes from small to large and then to small, and the corresponding target changes from blurry to clear and then to blurry, it is judged that the movement of the focus mechanism adjustment process is normal, otherwise it is abnormal; at the same time, detect and analyze the image, find out the focal plane value Fm corresponding to the clearest image in the focusing process, and compare it with the standard focal plane value Fb. If |Fm-Fb|<10, the best focal plane of the thermal imager meets the requirements, otherwise it does not meet the requirements; c) Thermal imager polarity adjustment function test: collect images before and after the thermal imager adjusts its polarity, and analyze whether the grayscale value of the image target is reversed before and after the polarity change. If reversed, the polarity adjustment function is normal, otherwise it is abnormal; d) Thermal imager fire control function test: send fire control commands to the thermal imager to be tested, and receive fire control inverse codes. First, determine whether the control communication is normal through the inverse codes. Then collect fire control images, identify fire control characters, and determine whether the displayed characters are consistent with the set values. If the communication is normal and the characters are consistent with the set values, the fire control function of the thermal imager to be tested is normal. e) Thermal imager brightness, gain and edge enhancement adjustment function test: collect images before and after the thermal box is adjusted, then make a difference between the images collected before and after to obtain a difference image, and then calculate the average grayscale of the difference image. If the average grayscale is greater than 10, the adjustment function is normal, otherwise it is abnormal; f) Test the function of each thermal imager to be tested in turn according to the above methods and steps; Step 10: Determine whether the continuous working time of the thermal imager to be tested reaches the set value. If it does not reach the set value, repeat step 8. If it reaches the set value, exit the test step and complete the temperature test. Step 11: Count and sort the results detected in steps 1 to 10, draw conclusions, and store them in a database; Step 12: After the test is completed, turn off the thermal imager to be tested, wait for the high and low temperature test chamber to return to temperature, and turn off the heat source.

[0009] The automatic inspection method for batch high and low temperature working tests of thermal imagers of the present invention has a scientific design and is easy to use. The parallel guide rails are designed to drive the parallel light tubes to move in the high and low temperature test box, thereby avoiding the problem that personnel need to enter the high and low temperature test box for operation. The temperature setting in the high and low temperature test box, the movement of the parallel guide rails and the communication of the thermal imager are controlled to record and collect the output video of the thermal imager in real time. The image processing module is used to judge whether the thermal imager responds to the sent communication command, and the power supply of the abnormal thermal imager is cut off in time to avoid damage to the thermal imager. The whole inspection process does not require the participation of inspection personnel, thereby reducing the work intensity of the personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a top view of the structure of the inspection device of the present invention.

[0011] Figure 2 The following is a flow chart of the inspection steps.

[0012] Among them, there are a high and low temperature test chamber 1, a heating module 2, a parallel light tube 3, a parallel guide rail 4, a thermal imager 5 for inspection, a thermal imager bracket 6, a hard disk recorder 7, a video acquisition module 8, a serial port server 9, and a power control board 10. DETAILED DESCRIPTION

[0013] Embodiment 1: A method for automatically testing batch high and low temperature working tests of thermal imagers, the method is applied to an automatic testing device, the automatic testing device comprises a high and low temperature test chamber, a heating module, a collimator, parallel guide rails, a thermal imager bracket, a hard disk recorder, a video acquisition module, a serial port server and a power control board, the high and low temperature test chamber is a hollow box, the parallel guide rails and the thermal imager bracket are arranged in parallel in the high and low temperature test chamber, the thermal imager to be tested is installed on the thermal imager bracket; the collimator is installed on the parallel guide rails and slides along the parallel guide rails, The light-emitting aperture of the collimator is at the same height as the optical window of the thermal imager to be tested. The focal length of the collimator is 2m, the diameter is 130mm, and the length is 400mm. The heating module is installed at the target position of the collimator. The heating module is a heating sheet with a size of 30mmX30mm and a temperature difference range of 0-85℃. The video signal of the thermal imager to be tested is respectively connected to the hard disk recorder and the video acquisition module. The communication, control and fire control signals of the thermal imager to be tested are connected to the serial port server. The video acquisition module model is E413-S00, which is connected to the serial port server model Moxa Uport1650-16. The power supply of the thermal imager to be tested is connected to the power control board model LM2596. The high and low temperature test chamber, heating module, parallel guide rails and power control board are respectively connected to the serial port server.

[0014] The high and low temperature test chamber provides different ambient temperatures for the thermal imager to be tested. The serial port server controls the power on and off, temperature setting, insulation time and temperature change rate of the high and low temperature test chamber; the heating module provides a radiation source for the thermal imager; when the temperature is higher than the set value, the heating module stops heating; the moving step interval of the parallel guide rail is the center interval of the thermal imager bracket; the power control board provides power to the thermal imager, sets the voltage, and provides abnormal protection for voltage and current; the hard disk recorder saves the video image of the high and low temperature test process of the thermal imager; the video acquisition module acquires the output image of the thermal imager to be tested in real time; after the current thermal imager video image is detected to be normal, the video acquisition module switches to the video channel of the next thermal imager.

[0015] The specific inspection steps are as follows: Step 1: Set the test parameters, where the test temperature is set to -43℃ to 57℃ according to the specific thermal imager model, the test humidity is also set according to the specific thermal imager model, the insulation time is usually set to 4 hours, the thermal imager continuous working time is 4 hours, the reheating temperature and reheating insulation time are both set to 1 to 2 hours, and the high and low temperature test chamber, parallel guide rails and the thermal imager to be tested start working according to the parameters; Step 2: The high and low temperature test chamber is heated to the set temperature according to the temperature parameters; Step 3: After the temperature in the high and low temperature test chamber reaches the standard, it enters the insulation state, and the thermal imager to be tested is kept in the high and low temperature test chamber until thermal equilibrium is reached; Step 4: After the thermal imager to be inspected has reached its holding time, start the thermal imager to be inspected, and simultaneously turn on the image detection function and the timing function; Step 5: When the image to be tested enters the normal working state, the timing stops, and this moment is the start time. During the working period of the thermal imager to be tested, the voltage and current of the thermal imager are detected and recorded to monitor the power consumption; Step 6: Use a hard disk recorder to record the entire inspection process of the thermal imager to be inspected; Step 7: Collect and judge whether the image of the thermal imager to be inspected is normal through real-time or scheduled acquisition; if there is a flower screen, ink painting, flickering screen, poor uniformity or bright line, it is judged that the image of the thermal imager is abnormal, otherwise it is normal; Step 8: Turn on the heating module and set the temperature difference to 20°C to provide a heat source for the target; Step 9: The moving mechanism on the parallel rail drives the collimator to move through the parallel rail, so that the collimator is aligned with the large objective lens of the thermal imager to be inspected; according to the inspection items specified in the specification, the thermal imager to be inspected is inspected item by item. The inspection items and methods are as follows: a) Field of view switching time detection: The video acquisition module continuously acquires the image signal of the thermal imager to be inspected and records the time of acquiring the current frame. After the field of view switching is completed, the similarity of adjacent frames of the acquired images is compared and analyzed one by one. The time when the similarity starts to deteriorate is recorded as the field of view switching start time T1, and the time when the similarity becomes high again is recorded as the field of view switching completion time T2. The switching time Dt=T2-T1; b) Thermal imager focus function test: adjust the focal length of the thermal imager to be tested, first change the focus value to the minimum, then the focus division value to 1, and adjust the focus plane to the maximum value in the positive direction in sequence, and collect thermal images in sequence at each focus plane value state. After the adjustment is completed, analyze the clarity of the collected images. When the clarity of the collected target image changes from small to large and then to small, and the corresponding target changes from blurry to clear and then to blurry, it is judged that the movement of the focus mechanism adjustment process is normal, otherwise it is abnormal; at the same time, detect and analyze the image, find out the focal plane value Fm corresponding to the clearest image in the focusing process, and compare it with the standard focal plane value Fb. If |Fm-Fb|<10, the best focal plane of the thermal imager meets the requirements, otherwise it does not meet the requirements; c) Thermal imager polarity adjustment function test: collect images before and after the thermal imager adjusts its polarity, and analyze whether the grayscale value of the image target is reversed before and after the polarity change. If reversed, the polarity adjustment function is normal, otherwise it is abnormal; d) Thermal imager fire control function test: send fire control commands to the thermal imager to be tested, and receive fire control inverse codes. First, determine whether the control communication is normal through the inverse codes. Then collect fire control images, identify fire control characters, and determine whether the displayed characters are consistent with the set values. If the communication is normal and the characters are consistent with the set values, the fire control function of the thermal imager to be tested is normal. e) Thermal imager brightness, gain and edge enhancement adjustment function test: collect images before and after the thermal box is adjusted, then make a difference between the images collected before and after to obtain a difference image, and then calculate the average grayscale of the difference image. If the average grayscale is greater than 10, the adjustment function is normal, otherwise it is abnormal; f) Test the function of each thermal imager to be tested in turn according to the above methods and steps; Step 10: Determine whether the continuous working time of the thermal imager to be tested reaches the set value. If it does not reach the set value, repeat step 8. If it reaches the set value, exit the test step and complete the temperature test. Step 11: Count and sort the results detected in steps 1 to 10, draw conclusions, and store them in a database; Step 12: After the test is completed, turn off the thermal imager to be tested, wait for the high and low temperature test chamber to return to temperature, and turn off the heat source.

Claims

1. A method for automatic inspection of batch high and low temperature working tests of thermal imagers, characterized in that The inspection method is applied to an automatic inspection device, which includes a high and low temperature test chamber, a heating module, a collimator, parallel guide rails, a thermal imager bracket, a hard disk recorder, a video acquisition module, a serial port server and a power control board. The high and low temperature test chamber is a hollow box, and the parallel guide rails and the thermal imager bracket are arranged in parallel in the high and low temperature test chamber. The thermal imager to be inspected is installed on the thermal imager bracket; the collimator is installed on the parallel guide rails and slides along the parallel guide rails. The light output aperture of the collimator is at the same height as the optical window of the thermal imager to be inspected, and the heating module is installed at the target position of the collimator; the video signal of the thermal imager to be inspected is respectively connected to the hard disk recorder and the video acquisition module, the communication, control and fire control signals of the thermal imager to be inspected are connected to the serial port server, the video acquisition module is connected to the serial port server, the power supply of the thermal imager to be inspected is connected to the power control board, and the high and low temperature test chamber, the heating module, the parallel guide rails and the power control board are respectively connected to the serial port server; The specific inspection steps are as follows: Step 1: Set the test parameters, including test temperature, test humidity, holding time, continuous working time of the thermal imager, reheating temperature and reheating holding time. The heating module, parallel guide rails and the thermal imager to be tested in the high and low temperature test chamber start working according to the parameters; Step 2: The high and low temperature test chamber is heated to the set temperature according to the temperature parameters; Step 3: After the temperature in the high and low temperature test chamber reaches the standard, it enters the insulation state, and the thermal imager to be tested is kept in the high and low temperature test chamber until thermal equilibrium is reached; Step 4: After the thermal imager to be inspected has reached its holding time, start the thermal imager to be inspected, and simultaneously turn on the image detection function and the timing function; Step 5: When the image to be tested enters the normal working state, the timing stops, and this moment is the start time. During the working period of the thermal imager to be tested, the voltage and current of the thermal imager are detected and recorded to monitor the power consumption; Step 6: Use a hard disk recorder to record the entire inspection process of the thermal imager to be inspected; Step 7: Collect and judge whether the image of the thermal imager to be inspected is normal through real-time or scheduled acquisition; if there is a flower screen, ink painting, flickering screen, poor uniformity or bright line, it is judged that the image of the thermal imager is abnormal, otherwise it is normal; Step 8: Turn on the heating module and set a suitable temperature difference to provide a heat source for the target; Step 9: The moving mechanism on the parallel rail drives the collimator to move through the parallel rail, so that the collimator is aligned with the large objective lens of the thermal imager to be inspected; according to the inspection items specified in the specification, the thermal imager to be inspected is inspected item by item. The inspection items and methods are as follows: a) Field of view switching time detection: The video acquisition module continuously acquires the image signal of the thermal imager to be inspected and records the time of acquiring the current frame. After the field of view switching is completed, the similarity of adjacent frames of the acquired images is compared and analyzed one by one. The time when the similarity starts to deteriorate is recorded as the field of view switching start time T1, and the time when the similarity becomes high again is recorded as the field of view switching completion time T2. The switching time Dt=T2-T1; b) Thermal imager focus function test: adjust the focal length of the thermal imager to be tested, first change the focus value to the minimum, then the focus division value to 1, and adjust the focus plane to the maximum value in the positive direction in sequence, and collect thermal images in sequence at each focus plane value state. After the adjustment is completed, analyze the clarity of the collected images. When the clarity of the collected target image changes from small to large and then to small, and the corresponding target changes from blurry to clear and then to blurry, it is judged that the movement of the focus mechanism adjustment process is normal, otherwise it is abnormal; at the same time, detect and analyze the image, find out the focal plane value Fm corresponding to the clearest image in the focusing process, and compare it with the standard focal plane value Fb. If |Fm-Fb|<10, the best focal plane of the thermal imager meets the requirements, otherwise it does not meet the requirements; c) Thermal imager polarity adjustment function test: collect images before and after the thermal imager adjusts its polarity, and analyze whether the grayscale value of the image target is reversed before and after the polarity change. If reversed, the polarity adjustment function is normal, otherwise it is abnormal; d) Thermal imager fire control function test: send fire control commands to the thermal imager to be tested, and receive fire control inverse codes. First, determine whether the control communication is normal through the inverse codes. Then collect fire control images, identify fire control characters, and determine whether the displayed characters are consistent with the set values. If the communication is normal and the characters are consistent with the set values, the fire control function of the thermal imager to be tested is normal. e) Thermal imager brightness, gain and edge enhancement adjustment function test: collect images before and after the thermal box is adjusted, then make a difference between the images collected before and after to obtain a difference image, and then calculate the average grayscale of the difference image. If the average grayscale is greater than 10, the adjustment function is normal, otherwise it is abnormal; f) Test the function of each thermal imager to be tested in turn according to the above methods and steps; Step 10: Determine whether the continuous working time of the thermal imager to be tested reaches the set value. If it does not reach the set value, repeat step 8. If it reaches the set value, exit the test step and complete the temperature test. Step 11: Count and sort the results detected in steps 1 to 10, draw conclusions, and store them in a database; Step 12: After the test is completed, turn off the thermal imager to be tested, wait for the high and low temperature test chamber to return to temperature, and turn off the heat source.

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