Thermal insulation fireproof cable fire resistance detection method combining image recognition and infrared thermal imaging technology

Abstract

The invention relates to a method for detecting fire resistance of a heat-insulating fireproof cable by combining image recognition and an infrared thermal imaging technology. The detection device comprises a flamethrower, a high-temperature-resistant base plate, a cable fixing bolt, an infrared thermal imager and an image analysis host. The cable is installed on the high-temperature-resistant base plate through the cable fixing bolt, and the flamethrower is aligned with a jetting point to conduct flame jetting. The infrared thermal imager collects infrared thermal imaging images on the surface of the cable and sends the infrared thermal imaging images to the image analysis host, and the image analysis host analyzes the images, extracts temperature distribution characteristics and inputs the temperature distribution characteristics into the fire resistance detection model. The model predicts the high-temperature service life and the risk point position of the cable. According to the method, the accuracy and efficiency of fire resistance detection are improved, meanwhile, damage to the cable is avoided, and the method has important practical value.

Description

Technical Field

[0001] The present invention relates to the field of cable detection, and in particular to a fire resistance detection method for heat-insulated fireproof cables combining image recognition and infrared thermal imaging technology. Background Art

[0002] Traditional methods for testing the fire resistance of thermally insulated fireproof cables rely on direct observation and contact temperature measurement. These methods have many limitations, such as the inability to monitor the temperature distribution of the entire cable surface in real time, being easily disturbed by environmental factors, and possibly causing damage to the cable. In addition, traditional methods make it difficult to accurately predict the service life and potential risk points of cables under high temperature conditions, resulting in the inability to provide a scientific basis for cable maintenance and replacement.

[0003] Infrared thermography, also known as thermal imaging or infrared imaging, is a technology that uses infrared radiation to detect and measure the temperature distribution on the surface of an object. Based on the relationship between the thermal radiation energy emitted by the surface of an object and its temperature, it can be used for high temperature detection.

[0004] For example, CN117351020A discloses an online detection method and system based on the appearance of refractory materials, which collects refractory material production images at different stages in the refractory material forming process, and simultaneously collects thermal imaging images of the refractory materials in the drying stage and the sintering stage, analyzes the structural variation values ​​of the refractory materials at different stages in the refractory material forming process; analyzes the temperature variation values ​​of the refractory materials in the drying stage and the sintering stage; analyzes the defect potential value of the refractory material formed body; presets a defect potential threshold value of the refractory material formed body, and destroys the refractory material formed bodies that are greater than the defect potential threshold value.

[0005] It is mainly used to detect refractory materials during the production process and analyze the possible locations of defects. However, there is currently no thermal imaging analysis method for actual fire resistance testing of cables. Since thermal imaging is easily interfered by external air temperature, how to overcome the interference is one of the main problems that need to be solved. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a fire-resistant detection device for heat-insulated fireproof cables combining image recognition and infrared thermal imaging technology, including a flamethrower, a high-temperature resistant pad, a cable fixing bolt, an infrared thermal imager and an image analysis host;

[0007] The heat-insulating fireproof cable is installed on the high-temperature resistant pad through the cable fixing bolt, and the flamethrower is aimed at the injection point on the high-temperature resistant pad to spray the flame to perform the fire resistance test of the cable;

[0008] The infrared thermal imager collects infrared thermal imaging images of the cable surface during the detection process, and sends the collected thermal imaging images to the image analysis host;

[0009] The image analysis host analyzes the collected thermal imaging images, obtains the temperature distribution of the cable surface during the processed detection process, and inputs it into the fire resistance detection model;

[0010] The fire resistance detection model predicts the high-temperature service life of the cable and the location of the risk point based on the input cable surface temperature.

[0011] Also included are: a first adjustment bracket mounted on the bottom of the flamethrower for adjusting the height and horizontal position of the flamethrower to ensure accurate alignment of the flame spray;

[0012] A second adjustment bracket is installed at the bottom of the infrared thermal imager and is used to adjust the height and horizontal position of the infrared thermal imager to ensure accurate alignment of the infrared thermal imager;

[0013] The heat-insulating flame shield is arranged below the infrared thermal imager and slidably fixed on the second adjustment bracket to block the flame and heat generated by the flamethrower, protect the infrared thermal imager from damage, and reduce interference with the infrared thermal imaging detection results.

[0014] The high temperature resistant pad is provided with a plurality of cable fixing bolts for fixing the cables to be tested, wherein:

[0015] The fixing method of the cable to be tested meets the following test requirements to ensure the stability and safety of the cable during the test;

[0016] 1) The arrangement of the cables to be tested between the fixing bolts should avoid unnecessary stress concentration to simulate actual use conditions;

[0017] 2) The bending radius of the cable to be tested meets the minimum bending radius requirements specified by the cable manufacturer to prevent damage to the cable during the test;

[0018] 3) The cable fixing bolt allows the cable to expand naturally in a high temperature environment, reducing the mechanical stress caused by thermal expansion;

[0019] 4) The design and layout of the cable fixing bolts take into account the thermal conductivity characteristics of the cable to ensure the accuracy of the test results;

[0020] 5) The structure of the cable fixing bolt allows for quick installation and removal of cables to improve testing efficiency.

[0021] The device further comprises:

[0022] The water spray system is used to spray water on the cable after the flame spray stage to simulate the sprinkler effect in an actual fire situation. The water spray system includes evenly distributed water spray nozzles located above the cable to ensure that the cable surface is evenly covered with water mist during the water spraying process. The system is also equipped with a pressure regulator to control the water pressure to simulate sprinkler conditions of different intensities; a flow meter is used to accurately measure the water spray flow rate; and a timer controls the start and end time and interval period of the water spraying.

[0023] A mechanical impact device, used for applying mechanical impact to the cable during the flame spraying and / or water spraying stage to simulate the physical impact occurring in a fire, wherein the mechanical impact device comprises a mechanical arm for generating impact and a control unit for controlling the impact strength and frequency, the strength and frequency of the mechanical impact being adjusted according to a predetermined test procedure; the mechanical impact device comprises an impact hammer made of a heat-resistant material, used for applying mechanical impact to the cable, and a driving mechanism, which is connected to the impact hammer and controls its swing and impact strength; the control unit is used for programming and controlling the impact frequency and strength of the impact hammer to simulate different mechanical impacts occurring in a fire situation; and there is also a supporting structure for fixing the driving mechanism to ensure the stability of the entire device when applying impact.

[0024] The infrared thermal imager collects infrared thermal imaging images of the cable surface during the detection process, and sends the collected thermal imaging images to the image analysis host, specifically including:

[0025] Before flame spraying, an infrared thermal imager is used to perform preliminary imaging of the unheated cable to determine the position and range of the cable on the high-temperature resistant pad; the image analysis host receives the preliminary image and uses image processing software to detect and mark the outline of the cable to determine the exact position of the cable in the image; based on the position of the cable in the image, the image analysis host sets the area of ​​interest, which corresponds to the actual size and shape of the cable.

[0026] The specific treatment methods before flame spraying are:

[0027] First, place the cable in a constant temperature box for constant temperature treatment, take it out after the temperature stabilizes, and then fix the cable to be tested on a high temperature resistant pad;

[0028] The temperature of the thermostat is set at 40-60°C, and the constant temperature treatment time is 10 minutes or more;

[0029] After the cables are fixed, an infrared thermal imager is used to collect images immediately, and the collected thermal images are sent to the image analysis host;

[0030] The image analysis host processes the collected thermal imaging images, uses the temperature difference between the cable and the high-temperature resistant pad to separate the cable area from the thermal imaging image, and sets the area of ​​interest, which corresponds to the actual size and shape of the cable.

[0031] When collecting infrared images, the infrared thermal imager collects infrared thermal imaging images of the cable surface at a predetermined time interval to ensure that the temperature change process of the cable under the action of the flame is captured. After the surface temperature of the measured cable reaches the initial temperature of the measurement, the flamethrower is started to spray flames for measurement;

[0032] The infrared thermal imager continues to collect infrared thermal imaging images of the cable surface at predetermined time intervals, and sends the collected thermal imaging images to the image analysis host in real time;

[0033] After receiving the thermal imaging image, the image analysis host performs preprocessing to remove hot air and other environmental interference in the thermal imaging image, including background subtraction, image denoising and contrast enhancement to improve image quality and highlight the temperature changes on the cable surface. After preprocessing, the thermal imaging image of the preset area of ​​interest is segmented;

[0034] The image analysis host analyzes the image of the area of ​​interest to obtain the two-dimensional distribution data of the cable surface temperature distribution in each thermal imaging image; and further obtains the temperature data of the cable surface at different measurement moments based on this; and obtains a data cube, in which each moment corresponds to a two-dimensional distribution data of the cable surface temperature distribution;

[0035] The image analysis host inputs the data cube into the fire resistance detection model, and the fire resistance detection model calculates the predicted high temperature service life and risk location of the cable to be tested;

[0036] Among them, the method of background subtraction in the preprocessing is: first, the measurement of the complete steps is performed without setting up cables, and infrared thermal imaging background images at different times are collected to form a time series background image, that is, each thermal imaging background image corresponds to a measurement moment, and it is used as the thermal imaging background image; when performing background subtraction, the thermal imaging background image at the corresponding moment is used as the background to be subtracted from the thermal imaging image actually measured to obtain the thermal imaging image after background subtraction.

[0037] The image analysis host inputs the data cube into the fire resistance detection model, and the fire resistance detection model calculates the predicted high temperature service life and risk location of the cable to be tested as follows:

[0038] The image analysis host extracts features from the data cube, extracting the temperature peak, average temperature, uniformity of temperature distribution, location of hotspot areas, and diffusion speed;

[0039] Peak temperature: In each time point slice, the highest temperature point on the cable surface is determined by finding the maximum pixel value;

[0040] Temperature mean: In each time point slice, the average value of all pixel values ​​is calculated to obtain the average temperature of the cable surface;

[0041] Temperature gradient: Calculate the temperature change rate of each pixel in the slices at consecutive time points, and determine the rate and direction of temperature change by central difference method or gradient operator;

[0042] Hot spot distribution: Identify areas with temperatures above a preset threshold in slices at consecutive time points, and determine the location and diffusion pattern of the hot spot areas through clustering algorithms or connected domain analysis;

[0043] Temperature uniformity: Calculate the standard deviation or variance of the cable surface temperature to assess the consistency of the temperature distribution;

[0044] Build a fire resistance detection model that includes:

[0045] Input layer: receives feature vectors extracted from the data cube, each feature vector contains all the features extracted above;

[0046] Feature extraction layer: It consists of a series of convolutional layers, which are used to automatically learn and extract spatial features in the temperature distribution image;

[0047] Dimensionality reduction layer: It consists of pooling layers and is used to reduce the spatial dimension of features while retaining the most important features;

[0048] Feature fusion layer: It is composed of fully connected layers and is used to fuse and nonlinearly transform the learned features;

[0049] Sequence analysis layer: composed of recurrent neural networks or long short-term memory networks, used to analyze temperature change patterns in time series data;

[0050] Risk assessment layer: It consists of specific algorithms, using support vector machines or extreme learning machines, to assess the potential risk locations of cables at high temperatures;

[0051] Life prediction layer: It consists of regression algorithms, using linear regression, decision tree regression or neural network regression to predict the high temperature service life of the cable;

[0052] Output layer: Convert the results of the risk assessment layer and the life prediction layer into specific prediction values, and output the predicted high-temperature service life and risk location of the cable.

[0053] Use historical data to train the model and minimize the loss function by adjusting the model parameters;

[0054] The trained model is applied to the data cube to predict the high temperature service life and risk locations of the cables.

[0055] A method for detecting fire resistance of a heat-insulated fireproof cable combining image recognition and infrared thermal imaging technology, using the heat-insulated fireproof cable fireproof detection device, comprises the following steps:

[0056] Step 1: Preheating treatment: preheat the cable to be tested to 40-60°C in a constant temperature box for at least 10 minutes to distinguish the cable temperature from the temperature of the high temperature resistant pad;

[0057] Step 2: Install the cable to be tested, fix the heat-insulated and fire-proof cable to the high-temperature resistant pad through the cable fixing bolts, ensure that the cable layout meets the test requirements, avoid stress concentration, and maintain an appropriate bending radius;

[0058] Step 3: Initial imaging: Use an infrared thermal imager to perform preliminary imaging of the preheated cable to determine the position and range of the cable on the high temperature resistant pad;

[0059] Step 4: Flame spraying: start the flame sprayer to spray flames at the cable to simulate the fire resistance of the cable under fire conditions;

[0060] Step 5: Image acquisition: the infrared thermal imager collects infrared thermal imaging images of the cable surface at predetermined time intervals and sends them to the image analysis host in real time;

[0061] Step 6: Image preprocessing: the image analysis host preprocesses the received thermal imaging image, including background subtraction, image denoising, contrast enhancement, and removal of hot air and other environmental interference;

[0062] Step 7: Feature extraction, extracting features such as temperature peak, average temperature, temperature gradient, hot spot distribution and temperature uniformity from the preprocessed image;

[0063] Step 8: Data cube construction, the extracted features are combined into a data cube, and the two-dimensional temperature distribution data at each time point is used as a slice of the data cube;

[0064] Step 9: Model training: Use historical test data to train the fire resistance detection model and optimize the model parameters to minimize the prediction error;

[0065] Step 10: Performance prediction: input the data cube into the trained fire resistance detection model. The model analyzes the data cube and predicts the high-temperature service life and risk location of the cable. The fire resistance detection model outputs the prediction results, including the predicted high-temperature service life of the cable and the location of potential risk points, for users to evaluate the fire resistance performance of the cable.

[0066] Step 2 also includes:

[0067] Step 2-1: Before flame spraying, adjust the position of the heat insulation flame shield to ensure that it is properly fixed on the second adjustment bracket and located below the infrared thermal imager;

[0068] Step 2-2: Based on the flame characteristics of the flamethrower and the field of view of the infrared thermal imager, fine-tune the angle and direction of the thermal shield to minimize the direct impact of the flame and heat on the infrared thermal imager.

[0069] The beneficial effects of the present invention are:

[0070] Infrared thermal imaging technology is used to determine the detection range in advance by imaging the unheated cable, ensuring the accuracy and repeatability of the detection. This method of pre-determining the detection range allows the test to focus more on the key parts of the cable and improves the accuracy of the measurement. During the image acquisition process, the background subtraction technology effectively eliminates the interference of the flame and heat generated by the flamethrower on the infrared thermal imager, ensuring the authenticity and reliability of the image data. When determining the cable range, no additional equipment is required. Only the thermal imager itself can achieve positioning, which is more precise than using additional external imaging equipment, more accurate measurement, and lower cost.

[0071] The present invention provides a novel fire resistance detection device and method for heat-insulated fireproof cables by combining image recognition and infrared thermal imaging technology, which can effectively overcome the shortcomings of traditional methods. The device can monitor the temperature changes of cables under the action of flames in real time without contact, and predict the high-temperature service life and risk point location of cables through accurate temperature distribution analysis. In addition, the method improves the safety and accuracy of the test, reduces potential damage to the cable, and provides an efficient and reliable solution for evaluating the fire resistance performance of cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0073] Attached Figure 1 It is a front schematic diagram of the device of the present invention;

[0074] Attached Figure 2 It is a side schematic diagram of the device of the present invention;

[0075] Attached Figure 3 It is a structural diagram of the model of the present invention.

[0076] Wherein: flamethrower 1, high temperature resistant pad 2, cable fixing bolt 3, infrared thermal imager 4, first adjustment bracket 5, second adjustment bracket 6, heat insulation flame shield 7, cable to be tested 8. DETAILED DESCRIPTION

[0077] Embodiment 1:

[0078] See also Figure 1 and Figure 2 The present invention provides a fire-resistant detection device for heat-insulated fireproof cables that combines image recognition and infrared thermal imaging technology, including a flamethrower 1, a high-temperature resistant pad 2, a cable fixing bolt 3, an infrared thermal imager 4, and an image analysis host;

[0079] The heat-insulating fireproof cable is installed on the high-temperature resistant pad 2 through the cable fixing bolt 3, and the flamethrower 1 sprays the flame at the spraying point on the high-temperature resistant pad 2 to perform the fire resistance test of the cable;

[0080] The infrared thermal imager 4 collects infrared thermal imaging images of the cable surface during the detection process, and sends the collected thermal imaging images to the image analysis host;

[0081] The image analysis host analyzes the collected thermal imaging images, obtains the temperature distribution of the cable surface during the processed detection process, and inputs it into the fire resistance detection model;

[0082] The fire resistance detection model predicts the high-temperature service life of the cable and the location of the risk point based on the input cable surface temperature.

[0083] It also includes: a first adjustment bracket 5, mounted on the bottom of the flamethrower 1, for adjusting the height and horizontal position of the flamethrower 1 to ensure accurate alignment of the flame spray;

[0084] A second adjustment bracket 6 is installed at the bottom of the infrared thermal imager 4 and is used to adjust the height and horizontal position of the infrared thermal imager 4 to ensure accurate alignment of the infrared thermal imager 4;

[0085] The heat-insulating flame shield 7 is arranged below the infrared thermal imager 4 and is slidably fixed on the second adjustment bracket to block the flame and heat generated by the flamethrower 1, protect the infrared thermal imager 4 from damage, and reduce interference with the infrared thermal imaging detection results.

[0086] The high temperature resistant pad 2 is provided with a plurality of cable fixing bolts 3 for fixing the cables to be tested, wherein:

[0087] The fixing method of the cable to be tested meets the following test requirements to ensure the stability and safety of the cable during the test;

[0088] 1) The arrangement of the cables to be tested between the fixing bolts should avoid unnecessary stress concentration to simulate actual use conditions;

[0089] 2) The bending radius of the cable to be tested meets the minimum bending radius requirements specified by the cable manufacturer to prevent damage to the cable during the test;

[0090] 3) The cable fixing bolt 3 allows the cable to expand naturally in a high temperature environment, reducing the mechanical stress caused by thermal expansion;

[0091] 4) The design and layout of the cable fixing bolt 3 take into account the thermal conductivity characteristics of the cable to ensure the accuracy of the test results;

[0092] 5) The structure of the cable fixing bolt 3 allows for quick installation and removal of the cable to improve testing efficiency.

[0093] The device further comprises:

[0094] The water spray system is used to spray water on the cable after the flame spray stage to simulate the sprinkler effect in an actual fire situation. The water spray system includes evenly distributed water spray nozzles located above the cable to ensure that the cable surface is evenly covered with water mist during the water spraying process. The system is also equipped with a pressure regulator to control the water pressure to simulate sprinkler conditions of different intensities; a flow meter is used to accurately measure the water spray flow rate; and a timer controls the start and end time and interval period of the water spraying.

[0095] A mechanical impact device, used for applying mechanical impact to the cable during the flame spraying and / or water spraying stage to simulate the physical impact occurring in a fire, wherein the mechanical impact device comprises a mechanical arm for generating impact and a control unit for controlling the impact strength and frequency, the strength and frequency of the mechanical impact being adjusted according to a predetermined test procedure; the mechanical impact device comprises an impact hammer made of a heat-resistant material, used for applying mechanical impact to the cable, and a driving mechanism, which is connected to the impact hammer and controls its swing and impact strength; the control unit is used for programming and controlling the impact frequency and strength of the impact hammer to simulate different mechanical impacts occurring in a fire situation; and there is also a supporting structure for fixing the driving mechanism to ensure the stability of the entire device when applying impact.

[0096] The infrared thermal imager 4 collects infrared thermal imaging images of the cable surface during the detection process, and sends the collected thermal imaging images to the image analysis host, specifically including:

[0097] Before flame spraying, the unheated cable is preliminarily imaged using an infrared thermal imager 4 to determine the position and range of the cable on the high temperature resistant pad 2; the image analysis host receives the preliminarily imaged image and uses image processing software to detect and mark the outline of the cable to determine the exact position of the cable in the image; based on the position of the cable in the image, the image analysis host sets an area of ​​interest that corresponds to the actual size and shape of the cable.

[0098] The specific treatment methods before flame spraying are:

[0099] First, place the cable in a constant temperature box for constant temperature treatment, take it out after the temperature stabilizes, and then fix the cable to be tested on the high temperature resistant pad 2;

[0100] The temperature of the thermostat is set at 40-60°C, and the constant temperature treatment time is 10 minutes or more;

[0101] After the cables are fixed, an infrared thermal imager 4 is immediately used to collect images, and the collected thermal imaging images are sent to an image analysis host;

[0102] The image analysis host processes the collected thermal imaging image, uses the temperature difference between the cable and the high temperature resistant pad 2 to separate the cable area from the thermal imaging image, and sets the area of ​​interest, which corresponds to the actual size and shape of the cable.

[0103] When collecting infrared images, the infrared thermal imager 4 collects infrared thermal imaging images of the cable surface at a predetermined time interval to ensure that the temperature change process of the cable under the action of the flame is captured. After the surface temperature of the measured cable reaches the initial temperature of the measurement, the flame sprayer 1 is started to spray flame for measurement;

[0104] The infrared thermal imager 4 continues to collect infrared thermal imaging images of the cable surface at predetermined time intervals, and sends the collected thermal imaging images to the image analysis host in real time;

[0105] After receiving the thermal imaging image, the image analysis host performs preprocessing to remove hot air and other environmental interference in the thermal imaging image, including background subtraction, image denoising and contrast enhancement to improve image quality and highlight the temperature changes on the cable surface. After preprocessing, the thermal imaging image of the preset area of ​​interest is segmented;

[0106] The image analysis host analyzes the image of the area of ​​interest to obtain the two-dimensional distribution data of the cable surface temperature distribution in each thermal imaging image; and further obtains the temperature data of the cable surface at different measurement moments based on this; and obtains a data cube, in which each moment corresponds to a two-dimensional distribution data of the cable surface temperature distribution;

[0107] The image analysis host inputs the data cube into the fire resistance detection model, and the fire resistance detection model calculates the predicted high temperature service life and risk location of the cable to be tested;

[0108] Among them, the method of background subtraction in the preprocessing is: first, the measurement of the complete steps is performed without setting up cables, and infrared thermal imaging background images at different times are collected to form a time series background image, that is, each thermal imaging background image corresponds to a measurement moment, and it is used as the thermal imaging background image; when performing background subtraction, the thermal imaging background image at the corresponding moment is used as the background to be subtracted from the thermal imaging image actually measured to obtain the thermal imaging image after background subtraction.

[0109] The image analysis host inputs the data cube into the fire resistance detection model, and the fire resistance detection model calculates the predicted high temperature service life and risk location of the cable to be tested as follows:

[0110] The image analysis host extracts features from the data cube, extracting the temperature peak, average temperature, uniformity of temperature distribution, location of hotspot areas, and diffusion speed;

[0111] Peak temperature: In each time point slice, the highest temperature point on the cable surface is determined by finding the maximum pixel value;

[0112] Temperature mean: In each time point slice, the average value of all pixel values ​​is calculated to obtain the average temperature of the cable surface;

[0113] Temperature gradient: Calculate the temperature change rate of each pixel in the slices at consecutive time points, and determine the rate and direction of temperature change by central difference method or gradient operator;

[0114] Hot spot distribution: Identify areas with temperatures above a preset threshold in slices at consecutive time points, and determine the location and diffusion pattern of the hot spot areas through clustering algorithms or connected domain analysis;

[0115] Temperature uniformity: Calculate the standard deviation or variance of the cable surface temperature to assess the consistency of the temperature distribution;

[0116] Establish a fire resistance detection model, which includes, for example Figure 3 As shown:

[0117] Input layer: receives feature vectors extracted from the data cube, each feature vector contains all the features extracted above;

[0118] Feature extraction layer: It consists of a series of convolutional layers, which are used to automatically learn and extract spatial features in the temperature distribution image;

[0119] Dimensionality reduction layer: It consists of pooling layers and is used to reduce the spatial dimension of features while retaining the most important features;

[0120] Feature fusion layer: It is composed of fully connected layers and is used to fuse and nonlinearly transform the learned features;

[0121] Sequence analysis layer: composed of recurrent neural networks or long short-term memory networks, used to analyze temperature change patterns in time series data;

[0122] Risk assessment layer: It consists of specific algorithms, using support vector machines or extreme learning machines, to assess the potential risk locations of cables at high temperatures;

[0123] Life prediction layer: It consists of regression algorithms, using linear regression, decision tree regression or neural network regression to predict the high temperature service life of the cable;

[0124] Output layer: Convert the results of the risk assessment layer and the life prediction layer into specific prediction values, and output the predicted high-temperature service life and risk location of the cable.

[0125] Use historical data to train the model and minimize the loss function by adjusting the model parameters;

[0126] The trained model is applied to the data cube to predict the high temperature service life and risk locations of the cables.

[0127] Embodiment 2:

[0128] A method for detecting fire resistance of a heat-insulated fireproof cable combining image recognition and infrared thermal imaging technology, using the heat-insulated fireproof cable fireproof detection device, comprises the following steps:

[0129] Step 1: Preheating treatment: preheat the cable to be tested to 40-60°C in a constant temperature box for at least 10 minutes to distinguish the cable temperature from the temperature of the high temperature resistant pad 2;

[0130] Step 2: Install the cable to be tested, fix the heat-insulated and fire-proof cable to the high-temperature-resistant pad 2 through the cable fixing bolt 3, ensure that the cable layout meets the test requirements, avoid stress concentration, and maintain an appropriate bending radius;

[0131] Step 3: Initial imaging: using an infrared thermal imager 4 to perform preliminary imaging on the preheated cable to determine the position and range of the cable on the high temperature resistant pad 2;

[0132] Step 4: flame spraying, start the flame sprayer 1 to spray flames towards the cable to simulate the fire resistance performance of the cable under fire conditions;

[0133] Step 5: Image acquisition, the infrared thermal imager 4 acquires infrared thermal imaging images of the cable surface at predetermined time intervals and sends them to the image analysis host in real time;

[0134] Step 6: Image preprocessing: the image analysis host preprocesses the received thermal imaging image, including background subtraction, image denoising, contrast enhancement, and removal of hot air and other environmental interference;

[0135] Step 7: Feature extraction, extracting features such as temperature peak, average temperature, temperature gradient, hot spot distribution and temperature uniformity from the preprocessed image;

[0136] Step 8: Data cube construction, the extracted features are combined into a data cube, and the two-dimensional temperature distribution data at each time point is used as a slice of the data cube;

[0137] Step 9: Model training: Use historical test data to train the fire resistance detection model and optimize the model parameters to minimize the prediction error;

[0138] Step 10: Performance prediction: input the data cube into the trained fire resistance detection model. The model analyzes the data cube and predicts the high-temperature service life and risk location of the cable. The fire resistance detection model outputs the prediction results, including the predicted high-temperature service life of the cable and the location of potential risk points, for users to evaluate the fire resistance performance of the cable.

[0139] Step 2 also includes:

[0140] Step 2-1: Before flame spraying, adjust the position of the heat-insulating flame shield 7 to ensure that it is correctly fixed on the second adjustment bracket and is located below the infrared thermal imager 4;

[0141] Step 2-2: According to the flame characteristics of the flamethrower 1 and the field of view of the infrared thermal imager 4, fine-tune the angle and direction of the heat-insulating flame baffle 7 to minimize the direct impact of the flame and heat on the infrared thermal imager 4.

[0142] Thus far, the description of the above-described embodiments is provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the present disclosure. The individual elements or features of a specific embodiment are generally not subject to the limitations of the specific embodiment, but when applicable, they can be interchanged and used for selected embodiments even if not specifically shown or described. In many respects, the same element or feature also can be changed. This variation is not considered to be a departure from the present disclosure, and all such modifications are intended to be included in the scope of the present disclosure.

[0143] Example embodiments are provided so that the present disclosure will be thorough and the scope will be fully conveyed to those skilled in the art. In order to thoroughly understand the embodiments of the present disclosure, numerous details are set forth, such as examples of specific parts, devices, and methods. Obviously, for those skilled in the art, it is not necessary to use specific details, the example embodiments can be implemented in many different forms, and neither should be construed as limiting the scope of the present disclosure. In certain example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0144] Here, specialized vocabulary is used only for the purpose of describing specific example embodiments, and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a" and "the" used herein may be intended to include plural forms as well. The terms "including" and "having" are inclusive, and therefore specify the presence of the claimed features, wholes, steps, operations, elements and / or components, but do not exclude the presence or additional presence of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof. Unless the order of execution is clearly indicated, the method steps, processing and operations described herein are not interpreted as necessarily needing to be performed in the specific order discussed and shown. It should also be understood that additional or optional steps may be adopted.

Claims

1. A fire-resistant detection device for heat-insulated fire-resistant cables combining image recognition and infrared thermal imaging technology, characterized in that It comprises a flamethrower (1), a high temperature resistant pad (2), a cable fixing bolt (3), an infrared thermal imager (4) and an image analysis host; The heat-insulating fireproof cable is installed on the high-temperature resistant pad (2) through the cable fixing bolt (3), and the flame sprayer (1) is aimed at the spray point on the high-temperature resistant pad (2) to spray flames to perform fire resistance detection of the cable; the infrared thermal imager (4) collects infrared thermal imaging images of the cable surface during the detection process, and sends the collected thermal imaging images to the image analysis host; The image analysis host analyzes the collected thermal imaging images, obtains the temperature distribution of the cable surface during the processed detection process, and inputs it into the fire resistance detection model; The fire resistance detection model predicts the high-temperature service life of the cable and the location of the risk point based on the input cable surface temperature.

2. The fire resistance detection device for heat-insulated fireproof cables according to claim 1, characterized in that: The device further comprises: A first adjustment bracket (5) mounted on the bottom of the flamethrower (1) for adjusting the height and horizontal position of the flamethrower (1) to ensure accurate alignment of the flame spray; A second adjustment bracket (6), mounted on the bottom of the infrared thermal imager (4), for adjusting the height and horizontal position of the infrared thermal imager (4) to ensure accurate alignment of the infrared thermal imager (4); The heat-insulating flame shield (7) is arranged below the infrared thermal imager (4) and is slidably fixed on the second adjustment bracket, and is used to block the flame and heat generated by the flamethrower (1), protect the infrared thermal imager (4) from damage, and reduce interference with infrared thermal imaging detection results.

3. The fire resistance detection device for heat-insulated fireproof cables according to claim 1, characterized in that: The high temperature resistant pad (2) is provided with a plurality of cable fixing bolts (3) for fixing the cables to be tested, wherein: The fixing method of the cable to be tested meets the following test requirements to ensure the stability and safety of the cable during the test; 1) The arrangement of the cables to be tested between the fixing bolts should avoid unnecessary stress concentration to simulate actual use conditions; 2) The bending radius of the cable to be tested meets the minimum bending radius requirements specified by the cable manufacturer to prevent damage to the cable during the test; 3) The cable fixing bolt (3) allows the cable to expand naturally in a high temperature environment, reducing the mechanical stress caused by thermal expansion; 4) The design and layout of the cable fixing bolt (3) take into account the thermal conductivity characteristics of the cable to ensure the accuracy of the test results; 5) The structure of the cable fixing bolt (3) allows for quick installation and removal of the cable to improve testing efficiency.

4. The fire resistance detection device for heat-insulated fireproof cables according to claim 1, characterized in that: The device further comprises: The water spray system is used to spray water on the cable after the flame spray stage to simulate the sprinkler effect in an actual fire situation. The water spray system includes evenly distributed water spray nozzles located above the cable to ensure that the cable surface is evenly covered with water mist during the water spraying process. The system is also equipped with a pressure regulator to control the water pressure to simulate sprinkler conditions of different intensities; a flow meter is used to accurately measure the water spray flow rate; and a timer controls the start and end time and interval period of the water spraying. A mechanical impact device, used for applying mechanical impact to the cable during the flame spraying and / or water spraying stage to simulate the physical impact occurring in a fire, wherein the mechanical impact device comprises a mechanical arm for generating impact and a control unit for controlling the impact strength and frequency, the strength and frequency of the mechanical impact being adjusted according to a predetermined test procedure; the mechanical impact device comprises an impact hammer made of a heat-resistant material, used for applying mechanical impact to the cable, and a driving mechanism, which is connected to the impact hammer and controls its swing and impact strength; the control unit is used for programming and controlling the impact frequency and strength of the impact hammer to simulate different mechanical impacts occurring in a fire situation; and there is also a supporting structure for fixing the driving mechanism to ensure the stability of the entire device when applying impact.

5. The fire resistance detection device for heat-insulated fireproof cables according to claim 1, characterized in that: The infrared thermal imager (4) collects infrared thermal imaging images of the cable surface during the detection process, and sends the collected thermal imaging images to the image analysis host, which specifically includes: Before flame spraying, an infrared thermal imager (4) is used to perform preliminary imaging of the unheated cable to determine the position and range of the cable on the high temperature resistant pad (2); an image analysis host receives the preliminary image and uses image processing software to detect and mark the outline of the cable to determine the exact position of the cable in the image; based on the position of the cable in the image, the image analysis host sets an area of ​​interest, which corresponds to the actual size and shape of the cable.

6. The fire resistance detection device for heat-insulated fireproof cables according to claim 5, characterized in that: The specific treatment methods before flame spraying are: First, place the cable in a constant temperature box for constant temperature treatment, take it out after the temperature stabilizes, and then fix the cable to be tested on a high temperature resistant pad (2); The temperature of the thermostat is set at 40-60°C, and the constant temperature treatment time is 10 minutes or more; After the cable is fixed, an infrared thermal imager (4) is immediately used to collect images, and the collected thermal imaging images are sent to an image analysis host; The image analysis host processes the collected thermal imaging image, utilizes the temperature difference between the cable and the high temperature resistant pad (2), separates the cable area from the thermal imaging image, and sets an area of ​​interest, which corresponds to the actual size and shape of the cable.

7. The fire resistance detection device for heat-insulated fireproof cables according to claim 6, characterized in that: When collecting infrared images, the infrared thermal imager (4) collects infrared thermal imaging images of the cable surface at a predetermined time interval to ensure that the temperature change process of the cable under the action of the flame is captured. After the surface temperature of the measured cable reaches the initial temperature of the measurement, the flame sprayer (1) is started to spray the flame for measurement; The infrared thermal imager (4) continues to collect infrared thermal imaging images of the cable surface at predetermined time intervals, and sends the collected thermal imaging images to the image analysis host in real time; After receiving the thermal imaging image, the image analysis host performs preprocessing to remove hot air and other environmental interference in the thermal imaging image, including background subtraction, image denoising and contrast enhancement to improve image quality and highlight the temperature changes on the cable surface. After preprocessing, the thermal imaging image of the preset area of ​​interest is segmented; The image analysis host analyzes the image of the area of ​​interest to obtain the two-dimensional distribution data of the cable surface temperature distribution in each thermal imaging image; and further obtains the temperature data of the cable surface at different measurement times based on this; A data cube is obtained, in which each moment corresponds to a two-dimensional distribution data of the cable surface temperature distribution; The image analysis host inputs the data cube into the fire resistance detection model, and the fire resistance detection model calculates the predicted high temperature service life and risk location of the cable to be tested; Among them, the method of background subtraction in the preprocessing is: first, the measurement of the complete steps is performed without setting up cables, and infrared thermal imaging background images at different times are collected to form a time series background image, that is, each thermal imaging background image corresponds to a measurement moment, and it is used as the thermal imaging background image; when performing background subtraction, the thermal imaging background image at the corresponding moment is used as the background to be subtracted from the thermal imaging image actually measured to obtain the thermal imaging image after background subtraction.

8. The fire resistance detection device for heat-insulated fireproof cables according to claim 7, characterized in that: The image analysis host inputs the data cube into the fire resistance detection model, and the fire resistance detection model calculates the predicted high temperature service life and risk location of the cable to be tested as follows: The image analysis host extracts features from the data cube, extracting the temperature peak, average temperature, uniformity of temperature distribution, location of hotspot areas, and diffusion speed; Peak temperature: In each time point slice, the highest temperature point on the cable surface is determined by finding the maximum pixel value; Temperature mean: In each time point slice, the average value of all pixel values ​​is calculated to obtain the average temperature of the cable surface; Temperature gradient: Calculate the temperature change rate of each pixel in the slices at consecutive time points, and determine the rate and direction of temperature change by central difference method or gradient operator; Hot spot distribution: Identify areas with temperatures above a preset threshold in slices at consecutive time points, and determine the location and diffusion pattern of the hot spot areas through clustering algorithms or connected domain analysis; Temperature uniformity: Calculate the standard deviation or variance of the cable surface temperature to assess the consistency of the temperature distribution; Build a fire resistance detection model that includes: Input layer: receives feature vectors extracted from the data cube, each feature vector contains all the features extracted above; Feature extraction layer: It consists of a series of convolutional layers, which are used to automatically learn and extract spatial features in the temperature distribution image; Dimensionality reduction layer: composed of pooling layers, used to reduce the spatial dimension of features while retaining the most important features; Feature fusion layer: composed of fully connected layers, used to fuse and nonlinearly transform learned features; Sequence analysis layer: composed of recurrent neural networks or long short-term memory networks, used to analyze temperature change patterns in time series data; Risk assessment layer: It consists of specific algorithms, using support vector machines or extreme learning machines, to assess the potential risk locations of cables at high temperatures; Life prediction layer: It consists of regression algorithms, using linear regression, decision tree regression or neural network regression to predict the high temperature service life of the cable; Output layer: Convert the results of the risk assessment layer and the life prediction layer into specific prediction values, and output the predicted high-temperature service life and risk location of the cable. Use historical data to train the model and minimize the loss function by adjusting the model parameters; The trained model is applied to the data cube to predict the high temperature service life and risk locations of the cables.

9. A method for detecting fire resistance of heat-insulated fireproof cables by combining image recognition and infrared thermal imaging technology, using the fire resistance detection device for heat-insulated fireproof cables according to claim 8, characterized in that: The steps include: Step 1: preheating treatment, preheating the cable to be tested to 40-60°C in a constant temperature box for at least 10 minutes to differentiate the cable temperature from the temperature of the high temperature resistant pad (2); Step 2: Install the cable to be tested, and fix the heat-insulated and fire-proof cable to the high-temperature resistant pad (2) through the cable fixing bolt (3), ensuring that the cable layout meets the test requirements, avoids stress concentration, and maintains an appropriate bending radius; Step 3: Initial imaging: using an infrared thermal imager (4) to perform preliminary imaging on the preheated cable to determine the position and range of the cable on the high temperature resistant pad (2); Step 4: flame spraying, starting the flame sprayer (1) to spray flames towards the cable to simulate the fire resistance performance of the cable under fire conditions; Step 5: Image acquisition, the infrared thermal imager (4) acquires infrared thermal imaging images of the cable surface at predetermined time intervals and sends them to the image analysis host in real time; Step 6: Image preprocessing: the image analysis host preprocesses the received thermal imaging image, including background subtraction, image denoising, contrast enhancement, and removal of hot air and other environmental interference; Step 7: Feature extraction, extracting features such as temperature peak, average temperature, temperature gradient, hot spot distribution and temperature uniformity from the preprocessed image; Step 8: Data cube construction, the extracted features are combined into a data cube, and the two-dimensional temperature distribution data at each time point is used as a slice of the data cube; Step 9: Model training: Use historical test data to train the fire resistance detection model and optimize the model parameters to minimize the prediction error; Step 10: Performance prediction: input the data cube into the trained fire resistance detection model. The model analyzes the data cube and predicts the high-temperature service life and risk location of the cable. The fire resistance detection model outputs the prediction results, including the predicted high-temperature service life of the cable and the location of potential risk points, for users to evaluate the fire resistance performance of the cable.

10. The fire resistance detection method of heat insulation and fireproof cable combining image recognition and infrared thermal imaging technology according to claim 9 is characterized in that Step 2 also includes: Step 2-1: Before the flame is sprayed, adjust the position of the heat-insulating flame shield (7) to ensure that it is properly fixed on the second adjustment bracket and is located below the infrared thermal imager (4); Step 2-2: According to the flame characteristics of the flamethrower (1) and the field of view of the infrared thermal imager (4), the angle and direction of the heat-insulating flame shield (7) are finely adjusted to minimize the direct impact of the flame and heat on the infrared thermal imager (4).

Images