阅读说明：本技术 热红外探伤设备、检测方法及其用于风机叶片的作业方法 (Thermal infrared flaw detection equipment, detection method and operation method for fan blade ) 是由 王忠波 张栋 于 2019-09-02 设计创作，主要内容包括：本发明提供了热红外探伤设备、检测方法及其用于风机叶片的作业方法。本发明所涉及的设备可与图像计算机、热红外激励光源、三脚架、云台附件配套使用,构成热红外探伤系统。通过运行于图像计算机中的检测软件,可辅助人工完成被测物的内外部缺陷检测。本发明所涉及的设备所用的检测方法采用了局部增强的算法,并且利用超声波距离传感器进行缺陷尺寸检测以及确定最佳成像位置。本发明所涉及的设备用于风机叶片的作业方法是将上述设备安装在回型升降台上,从而一次升降即可完成对整个叶片的360度检测。本发明所涉及的设备结构简单、成本低廉,除风机叶片无损探伤之外,还可用于与风机叶片同类的复合材料的红外探伤。(The invention provides thermal infrared flaw detection equipment, a detection method and an operation method for a fan blade. The equipment can be matched with an image computer, a thermal infrared excitation light source, a tripod and a tripod head accessory to form a thermal infrared flaw detection system. The detection software running in the image computer can assist in manually completing the detection of the internal and external defects of the detected object. The detection method used by the device adopts a locally enhanced algorithm, and utilizes an ultrasonic distance sensor to detect the defect size and determine the optimal imaging position. The operation method of the device for the fan blade, which is related by the invention, is characterized in that the device is arranged on a clip-type lifting platform, so that 360-degree detection of the whole blade can be completed by one-time lifting. The device has simple structure and low cost, and can be used for infrared flaw detection of composite materials similar to the fan blades besides nondestructive flaw detection of the fan blades.)

1. A thermal infrared flaw detection device is characterized in that: including thermal infrared camera module, visible light camera module, ultrasonic wave distance sensor module, network relay module, network AD collection module, wireless giga net router module and power supply system, can form a complete set general image computer, thermal infrared excitation light source, tripod, with manual or electronic cloud platform annex, can be used to the thermal infrared of fan blade and other similar conforming materials and detect a flaw.

2. The thermal infrared flaw detection apparatus of claim 1, wherein: the mechanical structure design of the thermal excitation light source device can be matched with at least one external excitation light source, a tripod and a tripod head, the thermal excitation light sources with different sizes can be fixed through the clamp, and the equal-angle inclination of the double light sources can be realized through the scale turntable and the connecting rod, so that the imaging range of light on the thermal infrared camera is gathered.

3. A detection method for the thermal infrared flaw detection apparatus according to claim 1, characterized in that: the method enhances the quality of the thermal infrared image by using a local image enhancement algorithm, can effectively overcome the illumination influence and inhibit image noise, and presents more fine internal structure details of the measured object.

4. A detection method used in the thermal infrared flaw detection apparatus according to claim 1, characterized in that: the ultrasonic distance sensor is used for testing the distance between the ultrasonic distance sensor and a tested object, so that the influence of strong sunlight can be overcome, and the optimal imaging position can be found through distance measurement in use.

5. A detection method used in the thermal infrared flaw detection apparatus according to claim 1, characterized in that: and calibrating the camera at different imaging distances, and calculating the physical size corresponding to the image pixel through calibration data and interpolation during detection.

6. A method of operating a fan blade with the thermal infrared flaw detection apparatus of claim 1, comprising: the thermal infrared flaw detection device and the accessories thereof in the claim 1 are fixed by using a clip-type lifting platform, and the detection of the fan blade can be completed in 360 degrees in one lifting process.

Technical Field

The invention relates to the field of thermal infrared imaging and detection, in particular to equipment and a method for detecting internal defects of fan blades and other similar composite materials by using a thermal infrared imaging means.

Background

At present, the technical means of nondestructive testing of the quality of the fan blade mainly comprises infrared thermal imaging, ultrasonic scanning, X-ray imaging, laser interference imaging and the like. Among them, the infrared thermal imaging detection technology can detect several typical defects of the glass fiber blade. And, the larger the defect size, the shallower the depth, and the larger the maximum surface temperature difference formed during cooling, the easier it is to detect using an infrared thermal imager.

For the glass fiber reinforced composite material for manufacturing the wind turbine blade, the thermal imaging technology is a relatively applicable nondestructive testing method, and is particularly suitable for the defects of common layering and glue permeation types. Compared with other detection methods, the method has the characteristics of non-contact, simplicity in operation, low cost, easiness in real-time observation and the like, and is more suitable for field detection of the fan blade.

The infrared thermal imaging nondestructive detection technology is characterized in that according to the basic principle of infrared radiation, the internal energy flow condition of an object is measured by an infrared radiation analysis method, an infrared thermal imager is used for displaying a detection result, and defects are visually judged. The method is based on the heat conduction theory and the infrared thermal imaging theory. When the temperature of the object differs from the ambient temperature, a flow of heat is generated inside the object. If heat is injected into the object, a part of the heat flow is necessarily diffused inward, so that the temperature distribution of the surface of the object is changed.

1. For a defect-free object, when the heat flow is uniformly injected, the heat flow can be uniformly diffused to the inside or from the surface, so that the temperature field distribution of the surface is also uniform;

2. when the inside of an object has a heat insulation defect, heat flow can be blocked at the defect, heat accumulation is caused, and a local hot area with high temperature appears on the surface;

3. when the inside of the object contains the defect of heat conductivity, a local cold area with lower temperature is generated on the surface of the object.

As can be seen from the above three cases, when there is a defect inside the object, a temperature difference is formed between the defective area and the non-defective area of the object. And the temperature difference depends on the thermophysical properties of the material of the object, but also on the size of the defect, the distance from the surface and its thermophysical properties. Due to the existence of the local temperature difference of the object, the infrared radiation intensity is inevitably different, and the change condition of the temperature can be detected by using the thermal infrared imager so as to judge the condition of the defect.

Thermal infrared inspection has been popular as a real known technique for decades and has been widely used in various industries such as wind turbine blade inspection, aircraft skin inspection, silicon wafer internal inspection, and the like. When the technology is applied, the defect detection is generally carried out by adopting a method of combining external heat source excitation and thermal infrared camera imaging, and then the display is carried out by adopting an image enhancement method. Therefore, the innovativeness of the thermal infrared flaw detection method is not reflected in the comprehensive application of the common technical means, but reflected in more specific implementation details. Particularly, for the field detection of the fan blade, the influence of strong sunlight and strong wind in the environment and the influence of convenience of high-altitude operation are considered.

The infrared flaw detection equipment in the prior patent or the prior document has problems designed in some details, so that the actual detection effect is not ideal. For example, some devices employ a global image enhancement algorithm, such as a global image histogram equalization algorithm or a frequency domain algorithm based on fourier analysis, so that noise and details of an image are amplified together, and as a result, the image enhancement result is severely distorted, a large amount of pockmarks or pseudo details occur, the image enhancement result performs poorly in field applications, and users are misled.

When detecting fan blades in the field, the influence of wind is not negligible. Some infrared flaw detection equipment adopts a hot air gun as a heat source, and actually, the air blowing equipment based on air flow can easily take away heat by strong wind in the field, so that the imaging effect is poor. Some of the infrared devices in the patents use a laser distance measuring sensor as a basis for distance measurement, but actual measurement shows that the laser sensor is unstable or non-operative in strong sunlight.

The infrared flaw detection device in the prior patent uses a distance sensor to control the distance between the device and the measured object, but lacks measurement of the physical size of the defect of the measured object. In an actual detection scenario, a user needs to estimate the defect size to evaluate the severity of the defect, and record the severity in a detection report. Because current infrared inspection equipment generally adopts single infrared camera formation of image and improper laser rangefinder sensor range finding, so generally lack effective defect measurement function.

In addition, the height of the installed fan blades is very high, the height of a small fan is about 30-50 meters, and the height of the blades of some large fans can reach hundreds of meters. Currently, an effective detection method is lacked to improve the detection efficiency. In practical application scenarios and some patent documents, inspection is usually performed by means of basket operation. The operation mode has safety risk, and can only detect the single surface of the blade in the same hoisting mode, even can only detect the local width of the single surface, and cannot cover the width of the blade. Some documents suggest that the high-altitude detection is carried out by using a large-load tethered unmanned aerial vehicle, which is an idea that is not tested by practical application. The unmanned aerial vehicle is influenced by low-altitude air turbulence, is difficult to stabilize at a fixed position, and shakes all around to realize relative stability under the control of a control system. In such a shake, the focusing system for infrared imaging is hardly stable in principle, so that effective imaging is hardly possible. In addition, the drone cannot be too close to the blades to avoid collisions, with the effective distance recommended by the manufacturer being 2 meters away. This is too demanding for the control personnel of the drone in actual operation. At present, the price of a mooring unmanned aerial vehicle is high, the price of a wind power blade is not very high, the loss is large if collision or even falling occurs, and both detection parties cannot accept the price. Therefore, the aerial detection means based on the nacelle operation needs to be improved, and the detection means based on the tethered unmanned aerial vehicle is basically not feasible.

When manufacturing fan blades, the blade shells are usually made of glass fiber reinforced resin, the blade tips and the blade main beams are made of carbon fibers with higher strength, and the front edge, the rear edge and the shearing part are usually made of sandwich structure composite materials (namely sandwich core materials). These composites are not unique to fan blades and are also found in other areas such as aircraft skin manufacturing. Therefore, the method is mainly used for infrared flaw detection of the fan blades and the like, and can also be used for detection scenes of other similar composite materials.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, provide thermal infrared flaw detection equipment which is successfully applied on site, and provide a detection and operation method which can be applied on the site of fan blade detection.

In order to achieve the purpose, the invention adopts the following technical scheme:

according to an aspect of the present invention, there is provided an integrated thermal infrared flaw detection apparatus including

The visible light camera module has the functions of a full-high-definition resolution color image sensor, electric zooming, electric self-focusing, network communication and the like, and is used for acquiring an appearance image of a measured object;

the thermal infrared camera module has the functions of a thermal infrared image sensor with the resolution of not less than 384 x 288, electric focusing, network communication and the like, and is used for acquiring a thermal infrared temperature image of a measured object;

the ultrasonic distance sensor has the functions of measuring distance through ultrasonic waves and outputting current analog signals and is used for measuring the distance between equipment and a measured object;

the network relay module is provided with a plurality of relay output ports and a network control function and is used for controlling a power supply switch of a heat source through a network;

the network AD acquisition module is provided with a plurality of AD conversion input ports and is used for acquiring analog current signals transmitted by the distance sensor, converting the analog current signals into digital signals and communicating through a network;

the wireless gigabit network router circuit board has the functions of high-speed wireless gigabit communication, a plurality of wired network ports and the like, and is used for networking network components;

the 12V direct current stabilized voltage power supply is used for supplying power to electrical components in the equipment;

the 220V input three-phase connector provides external power for the equipment;

the two 220V output three-phase sockets can provide power for an external heat source and realize on-off control of the external heat source.

In actual use, the device is used with an external heat source, an image computer (preferably a tablet computer with a touch screen) and an associated pan-tilt-head-support. The external devices are standard parts and can be purchased in a customized mode on the market to serve as accessories of the external devices. The thermal infrared flaw detection equipment and peripheral accessories and detection software thereof are referred to as a thermal infrared flaw detection system in the disclosure.

During detection, an external heat source can be electrically connected to a 220V three-phase output port of the thermal infrared flaw detection equipment. Two high power output ports may be connected to 2-4 kilowatt heat sources (typically kilowatt halogen lamps). In one embodiment, the power per outlet is up to 2.5 kilowatts.

The thermal infrared flaw detection equipment and the heat source are fixed on an external tripod head through a support, and the tripod head is correspondingly fixed on a lifting tripod or other lifting platforms. The cradle head can be used for adjusting the up-down pitching and the horizontal tilting of the equipment so as to be beneficial to adjusting to the optimal imaging posture. The cradle head and the lifting platform can be manual or electric. During actual field test, manual cloud platform and support transportation and equipment more easily, electronic cloud platform then remote control more easily.

And when in detection, the image computer is independently powered or is powered by a battery. It communicates with the device via a wireless network. Because the bandwidth of wireless communication can reach giga, smooth transmission of double-spectrum image data and other data is guaranteed. Running in the image computer is high-performance detection software. The following functions can be realized through the software:

1) controlling the switch of the heat source. The detection software sends a switch instruction through a network to control the action of the network relay, so that the switch of the heat source is controlled;

2) the distance to the object to be measured is measured. The detection software reads the numerical value of the input channel of the AD module through the network, so that the current value output by the distance sensor is obtained, converted into an actual distance numerical value through calculation, and finally displayed on a screen;

3) acquiring video data of a visible light camera, and storing the video data as an image file, an image sequence file or a video file;

4) acquiring video data of a thermal infrared camera, performing enhanced display on each frame of image, and displaying the image as a pseudo-color image;

5) the thermal infrared image and the enhanced image thereof can be saved as an image file, an image sequence file or a video file;

6) when the defect image data is accumulated enough, the detection software can further provide a function of auxiliary image recognition to automatically identify the defect position;

7) the action of the electric cradle head or other peripheral components can be controlled.

According to one embodiment of the invention, after the thermal infrared flaw detection system is assembled and powered on in the field, the following technical steps are used for detection:

the method comprises the following steps: adding the image computer into a wireless network of the equipment router, running detection software and checking that each function is correct;

step two: moving the system to a detection point, finding the optimal imaging distance according to the numerical value fed back by the distance sensor, and then opening a heat source;

step three: opening visible light video stream and thermal infrared video stream in detection software, and starting an image enhancement function;

step four: and inspecting the appearance defects of the object to be inspected according to the visible light video and inspecting the internal defects of the object to be inspected according to the thermal infrared video stream. From experience in practical applications, the inspection can be carried out after 5-10 seconds of heating. Under strong sunlight irradiation, some blade parts can be inspected immediately even by unequal heating;

step five: if a defect is found, a picture, a sequence of pictures or a video file may be saved for recording and the size of the defect may be measured for reporting.

In the steps, some technical means are adopted, and some defects in the prior art are overcome:

first, the ultrasonic sensor is not affected by strong sunlight, which overcomes the weakness of most laser sensors.

Second, we require the device to operate near the optimal imaging distance in use. By using a light source as a heat source, there is an optimal spot location. Therefore, the heating efficiency is highest when working near this distance: thermal radiation is attenuated too far away and the light source is not focused too close. Before the imaging device is delivered to a factory for use, the optimal imaging distance is found through theoretical analysis and experiments, and then the imaging distance is as close as possible to the imaging distance in the field use, so that the highest heat radiation efficiency can be ensured.

Third, we introduce the physical measurement function of defects. Before equipment leaves a factory, calibrating a camera at different distances to obtain a physical size corresponding to a pixel at the current distance. In the use of the device, the size of the defect in the image can be roughly measured by measuring the object distance and combining interpolation calculation.

Further, the image enhancement algorithm is improved, so that the image enhancement function in the invention is obviously superior to the algorithm function in the prior patent. Different from the practice in the prior patent, a local enhancement algorithm is mainly adopted, and parameter optimization is performed on imaging of composite materials such as fan blades and the like under strong sunlight.

It is well known that human vision is sensitive to high frequency image signals. The basic principle of image enhancement is to reduce the low-frequency area and highlight the high-frequency area, so as to strengthen the details and achieve the purpose of enhancement. The method of the prior patent adopts a global high-frequency signal enhancement method, which enhances the details in the image, but inevitably amplifies the noise at the same time. Under the action of the algorithm, high-degree pockmark noise appears in the real-time image, the quality of the image is seriously influenced, and some pseudo defects are possibly generated. In addition, due to uneven outdoor illumination, the brightness of each part of the image is different. The global enhancement algorithm is applied to the whole image, which causes the image quality of some local areas to be deteriorated. On the contrary, the local enhancement algorithm considers the uneven brightness of the system, removes noise through low-pass filtering to a certain degree, amplifies local high-frequency signals through local calculation, and finally obtains an enhanced image with clear details and more natural characteristics. Commonly used algorithms for local enhancement include Adaptive Histogram Equalization (AHE) algorithms, Automatic Contrast Enhancement (ACE) algorithms, and the like. The optimal parameters are summarized through a large number of pictures actually measured on site, so that the imaging effect on the composite materials of the fan blades is the best.

Because the locally enhanced algorithm is adopted and the performance is fully optimized, the requirement on the imaging quality of the thermal infrared camera is reduced, and the configuration requirement on the computer is not high, the cheaper thermal infrared camera and the image computer can be adopted, so that the cost of the equipment is obviously reduced.

When the infrared flaw detection operation of the wind power blade is carried out on the site of the fan, in order to overcome the limitation of the existing method, the invention provides that the return type lifting platform is used for hanging the equipment and the accessories, so that the detection of the fan blade can be carried out more efficiently.

According to one embodiment of the invention, a blade of a fan is adjusted to be vertical to the ground on the fan site, and a return type lifting platform is built around the blade. The clip-type lifting platform comprises a clip-type platform main body surrounding a fan blade, a guide wheel assembly, a winch, a safety lock and an electric cabinet, and an anti-collision device is arranged outside the clip-type lifting platform. When the device works, the straight fence body in a shape like a Chinese character 'hui' penetrates through the wind power blade and can freely lift up and down. There are mature devices on this type of platform market. The invention proposes to hang our equipment on such a device by means of a movable support. When the platform rises to a certain height, the staff can detect the two sides of the fan blade on the return type platform. Therefore, the detection of the whole blade can be completed by one-time lifting, and the working efficiency is obviously improved.

Drawings

FIG. 1 is a schematic view showing the composition of electrical components of a thermal infrared flaw detection apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the thermal infrared inspection system according to an embodiment of the present invention;

FIG. 3 is a schematic view of a camera calibration according to an embodiment of the present invention;

FIG. 4 is a schematic mechanical structure diagram of a thermal infrared flaw detection apparatus according to an embodiment of the present invention;

FIG. 5 is a mechanical schematic diagram of a thermal infrared flaw detection apparatus according to another embodiment of the present invention;

fig. 6 is a schematic mechanical structure diagram of a clip-type lifting platform used in an embodiment of the present invention.

Wherein the reference numerals are as follows:

1. a thermal infrared flaw detector; 11. a visible light camera module; 12. an ultrasonic distance sensor module; 13. a thermal infrared camera module; 14. kilomega network wireless router circuit board; 15. a 12V direct current stabilized power supply; 16. a 220V input three-phase plug; 17. a network AD acquisition module; 18. a network relay acquisition module; 191 and 192, 220V output three-phase sockets.

21. An image computer; 22 and 23, a thermal excitation light source; 24. fan blades, etc.

3. Calibration target

41. A tripod; 42. a thermally activated light source; 43. a visible light camera; 44. an ultrasonic distance sensor; 45. a thermal infrared camera; 46. a heat source fixture; 47. a dial scale; 48. a holder.

51. A tripod; 52. a thermally activated light source; 53. a visible light camera; 54. an ultrasonic distance sensor; 55. a thermal infrared camera; 56. a holder; 57. a bracket shell.

61. A platform body; 611. a side rail body; 612. a straight hurdle body; 613. 614, an anti-collision mechanism; 615. balancing weight; 616. a safety rack; 617. a stability maintaining frame; 62. a guiding component; 63. a winch; 64. a safety lock; 65. an electric cabinet.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repetitive description will be omitted.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the subject matter of the present disclosure can be practiced without one or more of the specific details, or with other methods, components, devices, steps, and the like. In other instances, well-known structures, methods, devices, implementations, materials, or operations are not shown or described in detail to avoid obscuring aspects of the disclosure.

As shown in fig. 1, a thermal infrared flaw detection apparatus 1 according to an embodiment of the present invention is in an all-in-one machine form, and includes a visible light camera module 11, a thermal infrared camera module 13, an ultrasonic distance sensor module 12, a gigabit wireless router circuit board 14, a 12V dc regulated power supply module 15, a network AD acquisition module 17, a network relay module 18, and 220V input three-phase plugs 16, 220V output three-phase sockets 191 and 192.

The image acquisition resolution of the visible light camera module 11 is 1920 × 1080 or more, that is, a high-definition camera, and has functions of ethernet communication, optical zooming, automatic focusing, manual focusing and the like. The visible light camera is used for shooting the appearance of a measured object and saving images as photos or video files.

The thermal infrared camera module 13 is used for shooting a thermal infrared temperature image of the measured object, and the internal defect of the measured object can be detected by using the temperature image. The light wave with a wavelength of 2.0 to 1000 μm is called thermal infrared. When infrared rays are transmitted on the ground, the infrared rays are absorbed by Atmospheric composition substances (particularly H2O, CO2, CH4, N2O, O3 and the like), the intensity is obviously reduced, the infrared rays only have better transmittance (Transmission) in two wave bands of 3-5 microns of medium waves and 8-12 microns of long waves, which are known as Atmospheric windows (Atmospheric windows), and most of thermal infrared imagers detect the two wave bands and calculate and display the surface temperature distribution of an object. In one embodiment of the present disclosure, we select a thermal infrared camera module with an acceptance spectrum of 8-14 μm to capture thermal infrared images of an atmospheric window segment of the object under test. In other embodiments, other thermal infrared camera modules with a receiving spectrum close to the atmospheric window band may be selected. Theoretically, the higher the acquisition resolution of the thermal infrared camera, the better. However, due to the price factor of the commercial product, we select a camera module with a resolution of 384 x 288 in one embodiment, and 640 x 480 in another embodiment. Through practical tests, the camera with the former resolution ratio can basically meet the precision requirement of field detection. The imaging effect of the latter camera is better, and especially the imaging is clearer when the shooting direction of the camera is not perpendicular to the surface of the measured object, which is attributed to the improvement of the resolution. In an embodiment of the disclosure, the thermal infrared camera module has a network communication function so as to facilitate networking.

The ultrasonic distance sensor 12 is for measuring a distance between the thermal infrared flaw detection device and the surface of the measured object, so that the user can control an optimum infrared imaging distance and estimate an approximate size of a defect in the image of the measured object from the current distance. In this embodiment, the optimal distance for infrared imaging is typically between 30-60 centimeters, depending on the radiation characteristics of the heat source. In order to measure the size of the defect, calibration of camera imaging at different distances is also required before the equipment leaves the factory. The embodiment of the invention adopts the ultrasonic sensor, and can overcome the defects of the laser distance sensor sold in the market. This is because a general laser sensor employs the optical distance measurement principle of TOF and may fail in strong sunlight. The ultrasonic sensor is not influenced by sunlight and works stably after field measurement.

The gigabit network wireless router circuit board 14 mainly plays a role of a network communication hub, and ensures that each networking component can perform high-speed network communication in a wired or wireless manner. Since the present system involves the transmission of image data, sufficient network communication bandwidth is required. According to the current state of the art and market products, one embodiment of the present disclosure is to select a gigabit wireless router with more than 3-4 wired LAN ports. A thermal infrared camera 13, a visible light camera 11, a network AD module 17 and a network relay module 18 in the equipment are all connected to a LAN port of the wireless router through Ethernet cables so as to realize the internal networking of the equipment. The external computer communicates with these internal components over a wireless network.

The 12V DC regulated power supply 15 is mainly used for supplying power to each internal electrical component of the equipment. In one embodiment, all internal dc electrical components are unified to a 12V supply. The 220V input three-phase plug 16 provides power to the dc regulated power supply 15 and provides ac power to the 220V output receptacles 191 and 192. The network relay module 18 is responsible for controlling the on and off of the output, and each AC output channel of the network relay module has the load capacity of about 2500W.

The network AD acquisition module 17 mainly functions to acquire the distance signal of the ultrasonic distance sensor 12. The ultrasonic distance sensor 12 outputs a 4-20ma direct current analog signal, transmits the signal to the AD module 17, and then converts the signal into a corresponding digital signal. An external computer can access the AD module 17 through a wireless network to obtain a specific digital value of the current and then convert the digital value into a corresponding distance value.

Fig. 2 is a schematic view of an inspection scene of the thermal infrared inspection apparatus according to an embodiment of the present invention. Wherein, the image computer 21 runs detection software, and communicates and controls with each networking component in the device in a wireless communication mode. The detection software can capture double-spectrum images of the visible light camera and the thermal infrared camera at the same time, and enhance and display the images to help a user to observe whether defects exist. The image enhancement algorithm mainly enhances the thermal infrared image, needs to adapt to the imaging characteristic of the composite material, enhances the internal defects and other internal structures of the composite material clearly, has certain inhibition on image noise, and has high real-time performance. Therefore, image enhancement algorithms are the core competitiveness of the present system. The image enhancement algorithm of the embodiment can achieve a processing speed of more than 25 frames/second on a machine of a common Inte I3 processor, namely the processing time for completing the thermal infrared image enhancement of one frame is within 40ms, and the image enhancement algorithm is remarkably superior to similar commercial equipment from the processing speed to the processing result. The detection software has the practical functions of controlling the on-off of a heat source, controlling the electric focusing of a camera, reading the current distance value and the like.

As shown in fig. 2, heat sources 22 and 23 are used to heat the test object 24 during the test. In actual measurement, the heating time is generally 5-10 seconds, and the maximum heating time does not exceed 30 seconds. If the outdoor wind power is large, the temperature of the object to be detected is ensured not to be reduced by continuously heating in the detection process. In one embodiment, the heat source may be a halogen lamp with a wattage or higher, or a special infrared bulb, and the light is collected by a light-collecting lamp cover. Under the outdoor windy condition, the lamp shade needs certain length to shelter from the bulb to prevent that the bulb heat from losing fast. Heat sources such as a hot air blower or a hot air gun which convects heat through air are not suitable for outdoor strong wind use scenes through field tests, and the effect of thermal infrared imaging is poor indirectly.

As shown in fig. 3, the checkerboard-like calibration targets are used for the calibration process of the thermal infrared camera. Before the equipment leaves a factory, the thermal infrared camera is calibrated once by using a conventional calibration algorithm at regular intervals, for example, 0.1 meter, and the relationship between the lens parameters, the camera image coordinate system and the world coordinate system at the distance can be obtained. The simplified calibration algorithm is to assume that the central axis of the camera lens is perpendicular to the calibration target, and directly calibrate the relationship between the image pixel and the actual physical size. And respectively calibrating different distance points within the range of 0.3-1.5 meters, and recording the calibration results into an electronic form. In practical application, according to the current distance, the physical size corresponding to each pixel can be obtained through interpolation calculation in the table. So that the location of the defect can be measured to some extent. Although the measurement result is rough, the measurement result can meet the use requirement of actual working conditions.

The mechanical structure design of one embodiment of the present invention is shown in fig. 4. This design is a universal design that can accommodate a variety of different thermal excitation source assemblies. The thermal excitation source 42 is held by a heat source holder 46 and fixed to the cabinet of the thermal infrared flaw detection apparatus. The fixture 46 can be adjusted up, down, left, and right to accommodate different sizes of thermally activated light sources. The related connecting rod device is driven by adjusting the knob on the dial 47, so that the two thermal excitation light sources 47 are obliquely opened at equal angles, the light source directions can be concentrated on the visual field area of the thermal infrared camera, and more efficient heating and imaging are realized. The tripod 41 is used for supporting the whole equipment and can adjust the height; the pan/tilt head 48 can be used to adjust the pitch and rotation of the entire thermal infrared inspection apparatus. The ultrasonic distance sensor 44 is used for measuring an imaging distance; the thermal infrared camera 45 and the visible light camera 43 are used for imaging the inside and outside of the object to be measured.

The mechanical structure design of another embodiment of the present invention is shown in fig. 5. This design is a simplified machining-oriented design that can accommodate a thermal excitation source assembly of a fixed size. The thermally activated light source 52 is fixed to the bracket housing 57 together with the thermal infrared device case. If the thermal excitation light source is replaced, the dimensions of the holder housing 57 need to be adjusted for rework assembly while maintaining the mechanical design of the other components. The tripod 51 is used for supporting the whole equipment and can adjust the height; the pan/tilt head 56 can be used to adjust the pitch and rotation of the entire thermal infrared inspection apparatus. The ultrasonic distance sensor 54 is used to measure an imaging distance; the thermal infrared camera 55 and the visible light camera 53 are used for imaging the inside and outside of the object to be measured.

As shown in fig. 6, a conventional clip-type lifting platform can be used for on-site efficient detection of fan blades. The infrared flaw detection equipment and the accessories thereof can be hung on the lifting platform. Wherein, the platform main body 61 is provided with a guide wheel assembly 62, a winch 63, a safety lock 64 and an electric cabinet 65. An operator may stand on the platform 61 for inspection. The counterweight 615 may ensure stability of the entire platform. The movable wheel at the front end of the anti-collision device 614 is in contact with the wind power base, so that the whole platform can be prevented from being in direct contact with the wind power base, and potential safety hazards are reduced. The straight fence body 612 is in a shape of a Chinese character 'hui', and penetrates through the wind power blade when the equipment works, so that an operator can detect the blade on the straight fence body 12 in 360 degrees.

The safety frame 616 is provided with the guide wheel assembly 62, the winch 63 and the safety lock 64. The two winches 63 and the two safety locks 64 are respectively arranged to form two sets of winch units. After the winch 63 is started, four steel wire ropes are hung from the fan frame, each set of winch unit needs two steel wire ropes, and one of the two steel wire ropes is used for the winch 63 and is used as a hoisting steel wire rope; the other is used for a safety lock 64 as a safety cable. Therefore, the whole device can rise stably, and the problems of inclination and safety are avoided. The whole rectangular-square-shaped platform is firstly assembled on the ground, and then a winch 63, a safety lock 64 and an electric cabinet 65 are installed after a platform main body 61 is assembled, and the equipment and accessories thereof are fixed on the platform main body 61. And then, moving the whole returning platform to the lower part of the blade, and hanging the steel wire rope. After the hoist 63 is started, the loop type platform is smoothly raised.

Through using this kind of returning the type platform to carry out hot infrared flaw detection, can ensure the formation of image stability at the in-process of detecting a flaw, be favorable to pressing close to the blade with the best formation of image distance and form an image to can show the efficiency that promotes blade detection, be applicable to present all types of fan blade and detect.