Infrared imaging circuit board fault detection method, device and system capable of suppressing interference

Abstract

The invention discloses an infrared imaging circuit board fault detection method, device and system capable of suppressing interference, and the method comprises the steps: driving an infrared camera to collect at least one frame of infrared image as a reference image when a to-be-detected circuit board is in a power-off state; after the to-be-tested circuit board is electrified, driving an infrared camera to acquire an infrared image as a real-time thermal imaging image; performing differential operation on the real-time thermal imaging image and the reference image to obtain a to-be-detected image after the environmental thermal interference is eliminated; and performing thermal anomaly fault detection on the to-be-detected circuit board based on the to-be-detected image. On the basis of not needing additional hardware equipment, ambient light interference is effectively eliminated, the fault detection precision is improved, and the adaptability of environmental conditions is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of image data processing, and particularly to an infrared imaging circuit board fault detection method, device, and system for suppressing interference. Background Art

[0002] With the continuous development of infrared imaging technology, its applications in multiple fields have gradually increased. Especially in the fault detection of electronic devices and circuit boards, infrared imaging has become an effective diagnostic tool. In circuit board fault diagnosis, an infrared camera can help engineers detect potential short circuits, overheating areas, or other abnormal phenomena by detecting the thermal distribution of the circuit board. The core advantage of infrared thermal imaging is its ability to non-contactingly monitor the circuit board in real time, quickly locate the fault point, thereby improving the fault troubleshooting efficiency and reducing human intervention.

[0003] However, through research by the applicant, it is found that during the infrared imaging process, the problem of ambient light interference always exists. Especially in a complex test environment, the influence of reflected light sources may cause unnecessary heat sources to appear in the image, thereby affecting the imaging accuracy. For example, materials such as metals, glass, and shielding covers on the circuit board to be tested may reflect the surrounding ambient light or infrared radiation, resulting in false heat sources in the image. This interference may not only lead to the failure of short circuit detection but also affect the fault diagnosis of other circuit boards, and even delay the maintenance and repair of equipment in case of emergency.

[0004] Specifically in the application scenario of circuit boards, when the infrared camera is aimed at the circuit board to be tested, components such as metal pads, chip packages, and shielding covers on the surface of the circuit board will all reflect ambient light. For example, the reflected light from hand operations or surrounding objects may be captured by the infrared camera, forming additional heat source signals that interfere with the true circuit board thermal imaging signal. The influence of this reflected light source may cause relatively large measurement errors, especially in short circuit detection and cases where the temperature difference is small.

[0005] Therefore, how to effectively identify and remove ambient light interference in infrared imaging, especially during the circuit board fault diagnosis process, remains an urgent technical problem to be solved. Summary of the Invention

[0006] Based on the above situation, the main object of the present invention is to provide an infrared imaging circuit board fault detection method, device, and system for suppressing interference, so as to effectively identify and remove ambient light interference in infrared imaging during the circuit board fault diagnosis process.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] In the first aspect, an embodiment of the present invention discloses an infrared imaging circuit board fault detection method for suppressing interference, including:

[0009] Step S100: When the circuit board to be tested is in a power-off state, drive an infrared camera to collect at least one frame of infrared image as a reference image, and the reference image is an infrared image of environmental heat source reflection interference.

[0010] Step S200: After the circuit board to be tested is powered on, drive the infrared camera to collect an infrared image as a real-time thermal imaging image, and the real-time thermal imaging image is an infrared image of the circuit board to be tested in the powered-on working state.

[0011] Step S300: Perform a differential operation on the real-time thermal imaging image and the reference image to obtain a test image after eliminating environmental heat interference, and the test image is an infrared image used for thermal anomaly detection of the circuit board to be tested.

[0012] Step S400: Perform thermal anomaly fault detection on the circuit board to be tested based on the test image.

[0013] Optionally, the acquisition timing of the reference image satisfies: the power-off time of the circuit board to be tested exceeds the thermal equilibrium time constant of the reference image, and the relative spatial position between the environmental heat source and the circuit board conforms to the preset detection tooling constraint conditions.

[0014] Optionally, in step S300, for the shielding cover area of the circuit board to be tested, a weighted differential algorithm is used to calculate the image difference, and the weighting coefficient K is calculated according to the following formula:

[0015] K = 1 + α·(Tenv - Tref)

[0016] Where α is the material reflectivity correction factor of the shielding cover area, Tenv is the current ambient temperature, and Tref is the ambient temperature at the time of collecting the reference image.

[0017] Optionally, before step S100, it further includes:

[0018] Control the circular polarizing filter in the infrared camera to rotate to a polarization angle orthogonal to the direction of the reflected light from the circuit board surface or other interference sources.

[0019] Optionally, step S100 includes:

[0020] Control the shutter of the infrared camera to be in an incompletely blocked state, so that the environmental heat source can enter the sensor of the infrared camera through reflection;

[0021] Drive the infrared camera to collect a reference image, and the reference image contains the information of the environmental heat source reflected in the incompletely blocked state.

[0022] In a second aspect, an embodiment of the present invention discloses an infrared imaging circuit board fault detection device for suppressing interference, including:

[0023] A reference image acquisition module, configured to drive an infrared camera to collect at least one frame of infrared image as a reference image when the circuit board to be tested is in a power-off state, and the reference image is an infrared image of environmental heat source reflection interference;

[0024] A real-time thermal imaging module, configured to drive an infrared camera to collect an infrared image as a real-time thermal imaging image after the circuit board to be tested is powered on, and the real-time thermal imaging image is an infrared image of the circuit board to be tested in a powered-on working state;

[0025] An interference elimination module, configured to perform a differential operation on the real-time thermal imaging image and the reference image to obtain a tested image after eliminating environmental heat interference, and the tested image is an infrared image for performing thermal anomaly detection on the circuit board to be tested;

[0026] A fault detection module, configured to perform thermal anomaly fault detection on the circuit board to be tested based on the tested image.

[0027] Optionally, it further includes:

[0028] A polarization angle control module, configured to control the circular polarization filter in the infrared camera to rotate to a polarization angle orthogonal to the direction of the reflected light from the circuit board surface or other interference sources.

[0029] Optionally, the reference image acquisition module includes:

[0030] A shutter control unit, configured to control the shutter of the infrared camera to be in an incompletely blocked state, so that the environmental heat source can enter the sensor of the infrared camera through reflection;

[0031] A driving unit, configured to drive the infrared camera to collect a reference image, and the reference image includes environmental heat source information reflected in the incompletely blocked state.

[0032] In a third aspect, an embodiment of the present invention discloses a computer-readable storage medium, on which a computer program is stored, and the computer program stored in the storage medium is used to be executed by a processor to implement the method disclosed in the first aspect above.

[0033] In a fourth aspect, an embodiment of the present invention discloses an infrared imaging circuit board fault detection system for suppressing interference, including:

[0034] An infrared camera, configured to collect infrared images of the circuit board to be tested;

[0035] A controller, configured to be executed by a processor to implement the method disclosed in the first aspect above, or include the device disclosed in the second aspect above as claimed.

[0036] Beneficial effects:

[0037] An infrared imaging circuit board fault detection method, device, and system for suppressing interference according to an embodiment of the present invention can effectively eliminate interference caused by ambient light or heat source reflection by collecting a reference image in a power-off state of the circuit board and performing differential operations after the circuit board is powered on. Through the collection of the reference image, the system can capture the reflection information of the ambient heat source without the heat source of the circuit board itself. Then, by performing a difference with the real-time thermal imaging image, the influence of ambient light or reflected heat source on the image is subtracted, thereby ensuring that only real thermal anomalies are detected, and further improving the accuracy of circuit board fault detection. This differential method can significantly improve the accuracy of fault location. Especially when dealing with highly reflective areas such as shielding covers and metal pads, it can accurately locate the fault area of the circuit board and avoid errors caused by environmental interference.

[0038] In addition, this method removes the interference of ambient light through software processing (image differential operation), avoiding the need to rely on additional hardware (such as complex filters or special sensors). The implementation of this method reduces the complexity and cost of the device, enabling efficient and accurate fault detection based on existing infrared cameras. And because the nature of ambient light interference is diverse and may vary in different test environments, this method can flexibly adapt according to different environmental conditions by collecting reference images. This makes the method highly adaptable and can be widely applied in different circuit boards and test environments, ensuring accurate detection of circuit board fault points under various working conditions.

[0039] In summary, the solution of the embodiment of the present invention not only effectively eliminates ambient light interference, improves fault detection accuracy, but also enhances the adaptability to environmental conditions without the need for additional hardware devices. And by effectively eliminating ambient light interference and improving detection accuracy, the detection personnel can accurately identify the fault area of the circuit board in a short time, thereby improving the overall fault troubleshooting efficiency.

[0040] Other beneficial effects of the present invention will be described in the specific implementation manner through the introduction of specific technical features and technical solutions. Those skilled in the art should be able to understand the beneficial technical effects brought by the described technical features and technical solutions through these introductions. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The embodiments of the present invention will be described below with reference to the drawings. In the drawings:

[0042] Figure 1 It is a schematic diagram of a thermal imaging example of a circuit board to be tested at a certain moment disclosed in this embodiment;

[0043] Figure 2 It is a flowchart of an infrared imaging circuit board fault detection method for suppressing interference disclosed in this embodiment;

[0044] Figure 3 Schematic structural diagram of an infrared imaging circuit board fault detection device for suppressing interference disclosed in this embodiment;

[0045] Figure 4 Schematic principle diagram of an infrared imaging circuit board fault detection system for suppressing interference disclosed in this embodiment. Detailed implementation manners

[0046] The present invention will be described below based on embodiments, but the present invention is not limited to these embodiments only. In the following detailed description of the present invention, some specific details are described in detail. In order to avoid obscuring the essence of the present invention, well-known methods, processes, procedures, and components are not described in detail.

[0047] In addition, those of ordinary skill in the art should understand that the drawings provided herein are all for illustrative purposes and the drawings are not necessarily drawn to scale.

[0048] Unless the context clearly requires otherwise, the words "including", "comprising", and the like in the whole specification and claims should be construed in an inclusive sense rather than an exclusive or exhaustive sense; that is, the meaning of "including but not limited to".

[0049] In the description of the present invention, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0050] In order to effectively identify and remove ambient light interference from infrared imaging during the circuit board fault diagnosis process, this embodiment discloses an infrared imaging circuit board fault detection method for suppressing interference. Please refer to Figure 1 , Figure 1 Schematic diagram of a thermal imaging example of a circuit board to be tested at a certain moment disclosed in this embodiment. During the process of fault detection of the circuit board to be tested, the circuit board to be tested can be thermally imaged by an infrared camera. Through the thermal imaging picture, areas with abnormal colors can be found, so as to facilitate the user to determine the temperature abnormal area of the circuit board to be tested, so as to determine whether there are faults such as short circuits and overheating in the circuit board.

[0051] Please refer to Figure 2 , Figure 2 Flowchart of an infrared imaging circuit board fault detection method for suppressing interference disclosed in this embodiment. The method includes step S100, step S200, step S300, and step S400, where:

[0052] Step S100: When the circuit board to be tested is in a powered-off state, drive an infrared camera to collect at least one frame of infrared image as a reference image. In step S100, first ensure that the circuit board to be tested is in a powered-off state. The infrared camera will be driven to collect at least one frame of infrared image, and this image serves as the reference image. In this embodiment, the reference image mainly reflects the reflection influence of various heat sources in the environment (such as air temperature changes, infrared radiation emitted by surrounding devices, body temperature of staff, etc.) on the circuit board to be tested. Therefore, the so-called reference image is actually an infrared image of the reflection interference of environmental heat sources.

[0053] In this process, the heat source signals in the reference image do not originate from the heat generation of the circuit board itself, but enter the sensor of the infrared camera through the reflection of environmental heat sources. Therefore, these thermal signals can be regarded as interference signals of ambient light, and their role is to provide a reference for subsequent removal of environmental interference.

[0054] In the specific implementation process, when performing step S100, the circuit board to be tested needs to be in a powered-off state. This is because in the powered-off state, the circuit board itself does not generate heat, avoiding the heat source interference of the circuit board and enabling more accurate capture of the interference signals brought by the reflection of environmental heat sources. At this time, there is no current flowing through the circuit board to be tested, and all thermal imaging signals only come from the reflection of external environmental heat sources.

[0055] It should be noted that to ensure the accuracy of the reference image, the acquisition timing of the reference image needs to be precisely controlled. In the powered-off state, the temperature of the circuit board should reach thermal equilibrium with the temperature of the surrounding environment. At this time, the temperature change on the surface of the circuit board to be tested will be mainly caused by external heat sources rather than the heat generated by the circuit board itself. Therefore, before collecting the reference image, the circuit board to be tested needs to maintain a powered-off state for a period of time to stabilize its temperature and balance it with the environmental temperature. This time should be long enough to ensure that the reflection influence of environmental heat sources becomes the main component of the image.

[0056] In an optional embodiment, the infrared camera can be driven to collect multiple consecutive frames of images when the ambient temperature around the circuit board to be tested is stable, and take their average value as the reference image to improve the stability and accuracy of the image.

[0057] Step S200: After the circuit board to be tested is powered on, drive the infrared camera to collect an infrared image as a real-time thermal imaging image. In this embodiment, the so-called real-time thermal imaging image is an infrared image of the circuit board to be tested in the powered-on working state.

[0058] Different from the acquisition of the reference image in step S100, the real-time thermal imaging image in step S200 reflects the thermal distribution of the circuit board under test in the working state. Specifically, after the circuit board under test is powered on, components, pads, chips, etc. inside the circuit board will generate heat due to current flow, and this heat will cause the surface temperature of the circuit board to rise. The infrared camera obtains the real-time thermal imaging image of the circuit board under test in the working state by detecting the temperature changes on the surface of the circuit board.

[0059] The heat sources of the circuit board can include normal temperature rise, that is, the natural heat when the circuit board is working, or abnormal temperature rise caused by short circuit, overheating or other faults. Through these temperature differences, the infrared camera can accurately capture potential fault points on the circuit board, helping engineers to detect and locate problems in time and further improving the efficiency of fault diagnosis.

[0060] It should be noted that the real-time thermal imaging image collected in step S200 will be different from the reference image collected in step S100. The reference image mainly reflects the influence of ambient light and external interference heat sources on the circuit board, while in step S200, the image mainly reflects the heat and heat sources generated due to current flow after the circuit board is powered on. In order to identify potential fault points from it, it is necessary to distinguish and remove the interference components of the two through subsequent image processing, such as differential operation.

[0061] Step S300, perform a differential operation on the real-time thermal imaging image and the reference image to obtain the image under test after eliminating environmental thermal interference. In this embodiment, the image under test refers to the infrared image used for thermal anomaly detection of the circuit board under test. The so-called differential operation refers to comparing the reference image collected in step S100 with the real-time thermal imaging image collected in step S200 to eliminate the interference signal caused by environmental heat sources.

[0062] Specifically, the reference image mainly reflects the reflection influence of heat sources in the environment (such as radiation from surrounding equipment, human body heat, air temperature changes, etc.) on the surface of the circuit board in the power-off state of the circuit board under test. The reflection signals of these environmental heat sources do not come from the working state of the circuit board itself, so they belong to the ambient light interference components. The real-time thermal imaging image reflects the heat change generated in the working state caused by current flow after the circuit board under test is powered on. In order to accurately detect the fault points on the circuit board, it is necessary to remove these ambient light interference parts from the real-time image and only retain the heat source signals generated by the circuit board itself.

[0063] To achieve precise detection of circuit board fault points and remove the ambient light interference part from the real-time image, only the heat source signal generated by the circuit board itself is retained. In step S300, first, the ambient heat source reflection signal in the reference image is compared with the signal in the real-time thermal imaging image through differential operation. Specifically, the ambient light interference signal reflected in the reference image is subtracted from the real-time thermal imaging image to obtain a difference image. This difference image mainly reflects the temperature changes caused by current flow and fault points when the circuit board is powered on, removing the irrelevant thermal signals caused by ambient light reflection.

[0064] The image to be measured obtained through differential operation can eliminate the interference of ambient light and reduce the influence of external heat source reflection on the image. At this time, the heat source signal in the image to be measured more accurately represents the actual working state of the circuit board, including normal temperature rise and abnormal temperature rise caused by faults (such as short circuits, overheating, etc.). Therefore, the image to be measured can be used for subsequent fault detection and thermal anomaly diagnosis.

[0065] The image to be measured obtained through step S300 can provide more accurate heat source information for subsequent fault detection, helping engineers quickly locate the fault area on the circuit board, thereby improving the efficiency of fault diagnosis.

[0066] In order to enable more precise processing of regions with different thermal characteristics and improve the accuracy and efficiency of fault detection, in an alternative embodiment, the weighted differential algorithm can further include applying different weight coefficients to different temperature regions. Since different components on the circuit board may have different thermal distribution characteristics, there may be significant differences in temperature changes and heat source reflection among these components. For example, components such as metal pads, chip packages, and shielding covers on the circuit board usually have high thermal conductivity and reflectivity, and the temperature changes in these regions will have a greater impact on the thermal imaging image.

[0067] Therefore, different weight coefficients can be applied according to the temperature distribution of different regions of the circuit board to adapt to the thermal distribution characteristics of each component of the circuit board. In the weighted differential algorithm, a larger weight coefficient can be applied to the high-temperature regions (such as fault regions or overheating regions) on the circuit board, while a smaller weight coefficient is used for the low-temperature regions (such as normal working regions).

[0068] In this embodiment, based on the weighted difference processing of the temperature region, the environmental interference in the high-temperature region can be effectively reduced while maintaining the image accuracy in the low-temperature region. Through this method, the environmental interference can be effectively removed specifically for the high-temperature region of the circuit board, reducing the generation of false signals, thereby improving the accuracy and efficiency of fault detection. That is, the adjustment of the weight coefficient enables more precise processing of regions with different thermal characteristics, and can effectively remove environmental interference specifically for the high-temperature region on the basis of maintaining the overall image accuracy, improving the accuracy and efficiency of fault detection.

[0069] Step S400, perform thermal anomaly fault detection on the circuit board to be tested based on the image to be tested. In the specific implementation process, common thermal imaging image analysis methods in the prior art can be used to determine whether there is a fault in the circuit board by identifying the temperature differences in the image. Specifically, the image to be tested shows the temperature distribution of each region of the circuit board, and analyzing these temperature distributions helps to distinguish normal temperature rise from abnormal overheating regions. By analyzing the temperature differences, it can be accurately determined whether there is a fault in the circuit board. Common fault types include short circuits, overheating, or other circuit problems, which usually cause the temperature of local regions to rise, thereby generating obvious thermal anomaly signals.

[0070] In order to ensure that the reference image is collected at the correct time to improve the accuracy of the reference image and further enhance the effect of suppressing environmental light interference, in an optional embodiment, the acquisition timing of the reference image satisfies: the power-off time of the circuit board to be tested exceeds the thermal equilibrium time constant τ of the reference image, and the relative spatial position between the environmental heat source and the circuit board conforms to the preset detection fixture constraint conditions. In this embodiment, the acquisition timing of the reference image needs to meet the following two key conditions:

[0071] 1. The power-off time of the circuit board to be tested exceeds the thermal equilibrium time constant τ of the reference image

[0072] In order to ensure that the reference image reflects the stable environmental interference signal rather than the heat source influence of the circuit board itself, the circuit board to be tested should be in the power-off state and maintained for a certain period of time. The power-off time should exceed the thermal equilibrium time constant τ of the circuit board. The thermal equilibrium time constant τ represents the time required for the surface temperature of the circuit board to reach the same as the environmental temperature. During this time, the temperature of the circuit board will gradually adjust to the temperature balance with the surrounding environment. Therefore, the image collected during this period mainly reflects the reflection signal caused by environmental light and is not affected by the heat source of the circuit board itself.

[0073] Ensuring that the circuit board to be tested is in a thermal equilibrium state helps to accurately capture the interference signal from the environment in the reference image without being interfered by the internal heat generation of the circuit board, thereby improving the effect of subsequent differential operations.

[0074] 2. The relative spatial position between the environmental heat source and the circuit board conforms to the preset constraints of the detection tooling

[0075] The acquisition of the reference image also needs to ensure that the reflection effect of the environmental heat source can stably enter the sensor of the infrared camera. To ensure that the reflection signal of the environmental heat source can accurately be reflected in the reference image, the relative spatial position between the circuit board and the environmental heat source needs to conform to the preset constraints of the detection tooling. For example, ensure that factors such as the angle, distance, and illumination between the infrared camera and the circuit board are not blocked or interfered by reflections from other objects. Through this control, unnecessary reflection interference in the acquired reference image can be avoided, further ensuring the accuracy of the acquired image.

[0076] In this embodiment, the requirements for the timing of acquiring the reference image are that the power-off time of the circuit board exceeds its thermal equilibrium time constant τ, and the relative position between the environmental heat source and the circuit board conforms to the preset constraints of the detection tooling. This requires waiting for the thermal equilibrium of the circuit board after power-off to ensure that the environmental interference of the reference image is minimized, and the calculation method based on the thermal equilibrium time constant can increase the accuracy of image acquisition.

[0077] To precisely process images of different regions, thereby improving the accuracy of detecting thermal anomaly faults, in an alternative embodiment, in step S300, for the shielded area of the circuit board to be measured, a weighted difference algorithm is used to calculate the image difference, and the weighting coefficient K is calculated according to the following formula:

[0078] K = 1 + α·(Tenv - Tref)

[0079] where α is the material reflectivity correction factor for the shielded area, Tenv is the current ambient temperature, and Tref is the ambient temperature at the time of acquiring the reference image.

[0080] Specifically, the shield is usually a metal material on the circuit board, with high thermal conductivity and reflectivity. Since these metal surfaces are prone to reflecting heat sources in the surrounding environment (such as equipment radiation, human body temperature, etc.), in the acquired infrared image, the shielded area may have a stronger reflection signal than other areas. This signal will interfere with the actual heat source signal, especially during thermal anomaly detection, which may lead to misjudgment.

[0081] To solve this problem, the weighted difference algorithm can appropriately adjust the image of this area by calculating the weighting coefficient K for the shielded area. By adjusting the weighting coefficient, the environmental interference caused by the high reflectivity of the shielded area can be reduced, thereby more accurately detecting the true temperature change in this area, especially the temperature rise related to circuit faults. In the specific implementation process:

[0082] First, determine the regional reflection characteristics. Specifically, by pre - analyzing the thermal characteristics of different regions on the circuit board (especially the shield area), determine the reflectivity correction factor α for each region. The reflectivity of the metal material in the shield area is usually high, so a larger α value needs to be set to compensate for the influence of environmental interference in this region.

[0083] Secondly, perform weighted processing on the temperature difference. During the differential operation, weight the temperature difference in the shield area. Specifically, the difference value between the real - time thermal imaging image and the reference image is adjusted according to the weighting coefficient K, so that the environmental interference signal in this region is effectively suppressed.

[0084] Finally, calculate the image difference. Process the weighted difference image to remove the interference signal reflected by the environmental heat source, and only retain the heat source signal of the circuit board itself, especially the real temperature change in the shield area.

[0085] In this embodiment, the core idea of the weighted differential algorithm is that when performing differential operations, different weight coefficients are applied to different regions, and the weight coefficients are adjusted according to the material reflectivity correction factor and the environmental temperature, so that different regions can effectively suppress interference for the high - reflection regions of the circuit board according to their thermal distribution characteristics, ensuring the imaging quality.

[0086] By applying a weighting coefficient during differential calculation, especially in the shield area, the interference signal caused by the reflection of the environmental heat source can be effectively reduced. The shield area usually has a strong reflection signal in the infrared image due to the high reflectivity of the metal, and this signal does not represent the real heat source of the circuit board, which is likely to affect the accuracy of fault detection.

[0087] Through the weighted differential algorithm, these interferences can be effectively suppressed, and the accuracy of temperature changes in each region of the circuit board can be improved. Especially during thermal anomaly detection, the weighted differential algorithm can ensure that the thermal imaging signals in the shield area and other special regions more accurately reflect the actual working state of the circuit board, avoiding misjudgment caused by environmental reflection interference.

[0088] To further improve the accuracy of the infrared imaging image, in an optional embodiment, before step S100, it further includes: controlling the circular polarizing filter in the infrared camera to rotate to a polarization angle orthogonal to the direction of the reflected light from the circuit board surface or other interference sources.

[0089] Specifically, a circularly polarized filter is a common optical component mainly used to adjust the polarization state of light. Its basic principle is to allow light waves in a specific direction to pass through the filter, thereby filtering out light waves in other directions. In infrared imaging, a large number of heat sources in the environment (such as working equipment, surrounding objects, and staff) will be reflected onto the circuit board surface in different ways and finally reflected into the infrared camera. These reflected lights often interfere with the thermal signals of the circuit board itself, thus affecting the accuracy of the image.

[0090] By using a circularly polarized filter, most of the reflected light can be effectively filtered out during the image acquisition process, especially those reflected lights that are inconsistent with the surface direction of the circuit board. The polarization function of the circularly polarized filter can reduce the interference of ambient light, enabling the image obtained by the infrared camera to more truly reflect the actual temperature change on the circuit board surface.

[0091] In the specific implementation process, the circularly polarized filter in step S100 needs to be rotated to a specific angle, which is orthogonal to the reflection direction of the circuit board surface or other interference sources. Specifically, the polarization direction of the circularly polarized filter should form a 90-degree angle with the incident direction of the reflected light. The selection of this rotation angle can minimize the interference signals caused by the reflection of ambient light sources, ensuring that the infrared camera only receives signals related to the thermal radiation of the circuit board itself.

[0092] Because the thermal signals of many ambient reflection light sources may be very similar to the heat generation signals of the circuit board itself and are difficult to distinguish, in this embodiment, the use of a circularly polarized filter helps to eliminate the interference brought by the reflection light source in the image, especially those lights that are not perpendicularly incident on the surface of the circuit board to be measured in the environment. By filtering out these interfering light sources, the infrared camera can more accurately capture the thermal signals of the circuit board itself.

[0093] In addition, through the action of the polarization filter, the collected image can more clearly present the heat source distribution of the circuit board and reduce the impact of ambient light on the image quality. Especially when there are multiple interference sources in the image (for example, heat reflections from surrounding equipment or operators), the polarization filter can effectively improve the clarity and accuracy of the image. Moreover, it can adapt to different working environments. Especially in high-reflection circuit boards and complex test environments, its good anti-interference ability enables the infrared imaging system to provide more reliable images.

[0094] To ensure the reliability of the reference image and make the subsequent infrared image analysis more accurate, in an optional implementation, step S100 includes: controlling the shutter of the infrared camera to be in an incompletely blocked state, so that the ambient heat source can be reflected into the sensor of the infrared camera; driving the infrared camera to collect the reference image, and the reference image contains the ambient heat source information reflected in the incompletely blocked state.

[0095] Specifically, during the process of obtaining the infrared imaging reference image, the reflection of environmental heat sources will interfere with the thermal imaging image of the circuit board to be measured. Therefore, in order to more accurately capture the influence of environmental heat sources when collecting the reference image, the shutter of the infrared camera is not fully blocked, allowing a certain amount of environmental heat source signals to enter the sensor. Thus, the reference image can more completely contain the interference information of environmental heat sources, so as to more precisely eliminate environmental thermal interference in subsequent image differential processing.

[0096] In this embodiment, by controlling the shutter of the infrared camera to be in an incompletely blocked state, environmental heat sources can enter the sensor of the infrared camera through reflection, allowing a certain amount of environmental heat source signals to enter, improving the ability of the reference image to capture environmental thermal interference, making the subsequent interference elimination process more accurate, that is, enhancing the accuracy of environmental heat source interference information;

[0097] In addition, by adjusting the shutter, it can adapt to complex environments. Specifically, in different detection environments (such as laboratories, production lines, etc.), this method can flexibly adjust the blocking ratio of the shutter to adapt to the influence of heat sources in different environments, improving the applicability of detection.

[0098] In summary, this embodiment ensures the reliability of the reference image, making the subsequent infrared image analysis more accurate, and providing more stable thermal imaging data support for circuit board fault detection.

[0099] This embodiment also discloses an infrared imaging circuit board fault detection device for suppressing interference. Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of an infrared imaging circuit board fault detection device for suppressing interference disclosed in this embodiment. The device includes: a reference image acquisition module 100, a real-time thermal imaging module 200, an interference elimination module 300, and a fault detection module 400, where:

[0100] The reference image acquisition module 100 is used to drive the infrared camera to collect at least one frame of infrared image as the reference image when the circuit board to be measured is in a power-off state. The reference image is an infrared image with interference from the reflection of environmental heat sources;

[0101] The real-time thermal imaging module 200 is used to drive the infrared camera to collect infrared images as real-time thermal imaging images after the circuit board to be measured is powered on. The real-time thermal imaging images are infrared images of the circuit board to be measured in the powered-on working state;

[0102] The interference elimination module 300 is used to perform differential operation on the real-time thermal imaging image and the reference image to obtain a measured image after eliminating environmental thermal interference. The measured image is an infrared image used for thermal anomaly detection of the circuit board to be measured;

[0103] The fault detection module 400 is used to perform thermal anomaly fault detection on the circuit board to be tested based on the image to be tested.

[0104] In an alternative embodiment, it further includes:

[0105] A polarization angle control module, configured to control the circular polarization filter in the infrared camera to rotate to a polarization angle orthogonal to the direction of the reflected light from the circuit board surface or other interference sources.

[0106] In an alternative embodiment, the reference image acquisition module 100 includes:

[0107] A shutter control unit, configured to control the shutter of the infrared camera to be in an incompletely occluded state, so that the environmental heat source can enter the sensor of the infrared camera through reflection;

[0108] A driving unit, configured to drive the infrared camera to acquire a reference image, and the reference image contains the environmental heat source information reflected in the incompletely occluded state.

[0109] This embodiment also discloses an infrared imaging circuit board fault detection system for suppressing interference. Please refer to Figure 4 , Figure 4 which is a schematic diagram of the principle of an infrared imaging circuit board fault detection system for suppressing interference disclosed in this embodiment. The system includes: an infrared camera 100 and a controller 200, where:

[0110] The infrared camera 100 is used to acquire the infrared image of the circuit board 300 to be tested;

[0111] The controller 200 is configured to be executed by a processor to implement the method disclosed in the above embodiment, or includes the device disclosed in the above embodiment.

[0112] According to an infrared imaging circuit board fault detection method, device and system disclosed in an embodiment of the present invention, by acquiring a reference image in the power-off state of the circuit board and performing differential operations after the circuit board is powered on, the interference caused by ambient light or heat source reflection can be effectively eliminated. Through the acquisition of the reference image, the system can capture the reflection information of the environmental heat source without the heat source of the circuit board itself. Then, by performing a difference with the real-time thermal imaging image, the influence of ambient light or reflected heat source on the image is subtracted, so as to ensure that only real thermal anomalies are detected, thereby improving the accuracy of circuit board fault detection. This differential method can significantly improve the accuracy of fault location. Especially when dealing with high-reflection areas such as shielding covers and metal pads, it can accurately locate the fault area of the circuit board and avoid errors caused by environmental interference.

[0113] In addition, this method removes the interference of ambient light through software processing (image differential operation), avoiding the need to rely on additional hardware (such as complex filters or special sensors). The implementation of this method reduces the complexity and cost of the device, enabling efficient and accurate fault detection based on existing infrared cameras. Moreover, due to the diverse nature of ambient light interference and its possible variations in different test environments, this method can flexibly adapt according to different environmental conditions by collecting reference images. This makes the method highly adaptable and able to be widely applied in different circuit boards and test environments, ensuring accurate detection of fault points on the circuit board under various working conditions.

[0114] In summary, the solution of the embodiment of the present invention, without the need for additional hardware devices, not only effectively eliminates ambient light interference, improves the accuracy of fault detection, but also enhances the adaptability to environmental conditions. And by effectively eliminating ambient light interference and improving the detection accuracy, the detection personnel can accurately identify the fault area of the circuit board in a short time, thus improving the overall fault troubleshooting efficiency.

[0115] In addition, the present invention also provides a computer-readable storage medium, such as a chip, an optical disc, etc. A program for execution is stored on the computer-readable storage medium, and when the program for execution is executed, the method described in any one of the above is implemented.

[0116] It should be noted that the computer-readable storage medium described in the embodiments of the present disclosure is not limited to the above-given embodiments. For example, it can also be an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the embodiments of the present disclosure, the computer-readable storage medium can be any tangible medium that contains or stores a program, and the program can be used by or in combination with an instruction execution system, apparatus, or device.

[0117] Those skilled in the art can understand that, on the premise of no conflict, the above-mentioned preferred solutions can be freely combined and superimposed. Among them, the flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and this module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, as well as the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions. The numbering of each step in this article is only for convenience of description and reference, and is not used to limit the order before and after. The specific execution order is determined by the technology itself, and those skilled in the art can determine various allowed and reasonable orders according to the technology itself.

[0118] It should be noted that in the present invention, step numbers (letter or number numbers) are used to refer to certain specific method steps, only for the purpose of convenient description and brevity, and by no means to limit the order of these method steps by letters or numbers. Those skilled in the art can understand that the order of relevant method steps should be determined by the technology itself and should not be unduly restricted by the existence of step numbers. Those skilled in the art can determine various allowed and reasonable step orders according to the technology itself.

[0119] Those skilled in the art can understand that, on the premise of no conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0120] It should be understood that the above-mentioned embodiments are merely exemplary and not restrictive. Without departing from the basic principles of the present invention, various obvious or equivalent modifications or substitutions made by those skilled in the art to the above details will be included within the scope of the claims of the present invention.

Claims

1. A method for detecting faults in a circuit board using infrared imaging with interference suppression, characterized in that: include: Step S100, when the circuit board to be tested is in a power-off state, driving the infrared camera to collect at least one frame of infrared image as a reference image, wherein the reference image is an infrared image with reflection interference from an environmental heat source; Step S200, after the circuit board to be tested is powered on, driving the infrared camera to collect an infrared image as a real-time thermal imaging image, wherein the real-time thermal imaging image is an infrared image of the circuit board to be tested in a powered-on working state; Step S300, performing a differential operation on the real-time thermal imaging image and the reference image to obtain an image to be tested after eliminating environmental thermal interference, wherein the image to be tested is an infrared image used to perform thermal anomaly detection on the circuit board to be tested; Step S400: performing thermal abnormality fault detection on the circuit board to be tested based on the image to be tested.

2. The method for suppressing ambient light interference in infrared thermal imaging according to claim 1, characterized in that: The acquisition timing of the reference image satisfies that: the power-off time of the circuit board to be tested exceeds the thermal equilibrium time constant (τ) of the reference image, and the relative spatial position of the environmental heat source and the circuit board meets the preset detection tooling constraint conditions.

3. The infrared imaging circuit board fault detection method according to claim 1, characterized in that: In the step S300, a weighted difference algorithm is used to calculate the image difference of the shielding cover area of ​​the circuit board to be tested, and the weighted coefficient K is calculated according to the following formula: K = 1 + α (Tenv - Tref) Wherein, α is the material reflectivity correction factor of the shielding cover area, Tenv is the current ambient temperature, and Tref is the ambient temperature when the reference image is collected.

4. The infrared imaging circuit board fault detection method according to any one of claims 1 to 3, characterized in that: Before step S100, the method further includes: The circular polarizing filter in the infrared camera is controlled to rotate to a polarization angle that is orthogonal to the direction of light reflected from the circuit board surface or other interference sources.

5. The infrared imaging circuit board fault detection method according to any one of claims 1 to 3, characterized in that: The step S100 includes: Controlling the baffle of the infrared camera to be in an incompletely shielded state so that the ambient heat source can enter the sensor of the infrared camera by reflection; The infrared camera is driven to acquire the reference image, wherein the reference image contains information of the ambient heat source reflected and entering in an incompletely blocked state.

6. An infrared imaging circuit board fault detection device with interference suppression, characterized in that: include: A reference image acquisition module (100) is used to drive an infrared camera to collect at least one frame of infrared image as a reference image when the circuit board to be tested is in a power-off state, wherein the reference image is an infrared image with reflection interference from an environmental heat source; A real-time thermal imaging module (200) is used to drive the infrared camera to collect an infrared image as a real-time thermal imaging image after the circuit board to be tested is powered on, wherein the real-time thermal imaging image is an infrared image of the circuit board to be tested in a powered-on working state; An interference elimination module (300) is used to perform a differential operation on the real-time thermal imaging image and the reference image to obtain an image to be tested after eliminating environmental thermal interference, wherein the image to be tested is an infrared image used to perform thermal anomaly detection on the circuit board to be tested; A fault detection module (400) is used to perform thermal anomaly fault detection on the circuit board to be tested based on the image to be tested.

7. The infrared imaging circuit board fault detection device according to claim 6, characterized in that: Also includes: The polarization angle control module is used to control the circular polarization filter in the infrared camera to rotate to a polarization angle orthogonal to the direction of light reflected from the circuit board surface or other interference sources.

8. The infrared imaging circuit board fault detection device according to claim 6, characterized in that: The reference image acquisition module (100) comprises: A baffle control unit, used to control the baffle of the infrared camera to be in an incompletely shielded state, so that the ambient heat source can enter the sensor of the infrared camera by reflection; A driving unit is used to drive the infrared camera to acquire the reference image, wherein the reference image contains information of ambient heat sources reflected and entering in an incompletely blocked state.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer program stored in the storage medium is used to be executed by a processor to implement the method according to any one of claims 1 to 5.

10. An infrared imaging circuit board fault detection system with interference suppression, characterized in that: include: Infrared camera, used to collect infrared images of the circuit board to be tested; A controller, configured to be executed by a processor to implement the method according to any one of claims 1 to 5, or comprising the device according to any one of claims 6 to 8.

Images