CN104359429B - Contact area measurement system based on image measuring technique - Google Patents

Abstract

The present application discloses a method for measuring contact area based on image measurement technology. The method includes the following steps: after the light source provides light, adjust the light range and scatter the light to provide a uniform light field for the contact body; load the contact body to form a contact area ;Using the camera to shoot the contact body loaded under the uniform light field, collecting the image of the contact part; analyzing the image of the contact part, identifying the boundary, determining the contact width and calculating the contact area between the contact bodies. The application also discloses a contact area measurement system based on image measurement technology, the system cooperates with contact bodies to measure the contact area between contact bodies, the system includes: backlight module, image acquisition module and contact area recognition module . The method and system have the advantages of non-contact, high precision, continuous and high-temperature environment measurement, and can automatically complete the measurement of the contact area under various working conditions.

Description

Contact Area Measurement System Based on Image Measurement Technology

technical field

This application relates to the fields of engineering structure design and image measurement, in particular, it relates to a contact area measurement system based on image measurement technology.

Background technique

Contact is very common in engineering applications, such as the meshing between two gears, the process of rolling a steel plate by the rolls of a rolling mill, the rolling of a wheel on a rail, and the contact of a bridge roller seat, etc.

The contact form of two objects is divided into point contact and line contact. The former is like the contact between a sphere and a plane, and the latter is like the contact between a cylinder and a plane. The two contact models are shown in Figure 1. In order to study the mechanical behavior of contact structures, such as measuring the contact strength of contact bodies, researchers need to measure the contact area between contact bodies. Since the contact area is blocked and cannot be directly observed, the measurement of the contact area becomes very difficult.

The development of the method of measuring the contact area has gone through two stages. The representative methods of the first stage are the indentation method and the scratch method. These methods measure the contact area by observing the traces left by the contact body during the contact process. The object is unloaded after contact loading, and the contact area is calculated by observing and measuring the geometric dimensions of the indentation and scratches left by the compressed object due to compression deformation. There are two obvious defects in this type of method: first, the indentation method and the scratch method cannot be continuously measured due to the continuous loading and unloading experimental method; second, the measurement resolution is very low. When the contact area is relatively small, the indentation method cannot Marks and scratches are often not visible.

In order to solve the defects of the above two methods, the method of measuring the contact area has been developed to the second stage, which is represented by the pressure paper method and the piezoelectric film method. In this method, a sensor is placed between two contact bodies, and the contact area of the contact object is measured. Convert to other information for measurement. The pressure paper method is to place two pieces of pressure paper (one is filled with dye capsules, and the other is attached with a color developer) between the contact bodies. The contact area on a layer of pressure paper will appear red, and finally the contact area is calculated by measuring the area of the red area. The piezoelectric film method is to place an electronic sensor or a sensitive grid between two contacting objects. When the object is contacted and pressed, the contact area will generate an electrical signal. The contact area can be measured by analyzing the position where the electrical signal is generated. This type of method for measuring the contact area solves the problem that the indentation method and the scratch method cannot be continuously measured, and greatly improves the measurement accuracy. However, this new method also has its own problems: first, pressure paper and piezoelectric film cannot be used in extreme experimental environments such as high temperature; second, the arrangement of sensing media in the contact area may change the properties of the interface, thereby Change the local mechanical properties of the contact area and affect the authenticity of the experimental results. From this point of view, the existing contact area measurement methods either have high requirements for the measurement environment, or have poor measurement accuracy, and are difficult to meet the measurement requirements of various contact areas.

Contents of the invention

The invention proposes a continuous measurement method for the contact area that can be used in different environments, and simultaneously designs and implements a corresponding measurement system. Based on image measurement technology, the method acquires the contact area by collecting and analyzing the images of the contact parts, and realizes continuous high-precision measurement. The measurement system built based on this method is simple in operation, low in consumption, and the data processing can be completed automatically. Aiming at the shortcomings of the existing techniques and methods for measuring the contact area, such as the inability to meet the measurement in high-temperature environments, the inability to observe continuously, the influence of the mechanical properties of the contact body itself, and the low accuracy, the present invention proposes a method that can meet the needs of different environments. The continuous measurement method of the contact area and the corresponding measurement system are provided at the same time.

The invention provides a method for measuring contact area based on image measurement technology, the method comprising the following steps:

After the light source provides light, adjust the light range and scatter the light to provide a uniform light field for the contact body;

Loading the contact body to form a contact area;

Use the camera to shoot the contact body loaded under the uniform light field, and collect the image of the contact part;

The image of the contact part is analyzed, the boundary is identified, the contact width is determined and the contact area between the contact bodies is calculated.

Preferably, after the light source provides the light, adjust the light range and scatter the light to provide a uniform light field for the contact body, further: after the light source provides the light, use the moving aperture to adjust the irradiation range, use the white screen to scatter the light, Provide a uniform light field for the contact body.

Preferably, the analyzing the image of the contact part, performing boundary recognition, determining the contact width and the contact area between the contact bodies, further includes:

When the contact body is a contact body formed by a sphere and a cube, the contact area is circular, the determined contact width is the diameter d of the contact area, and the contact area is equal to π×(d/2) ² ;

When the contact body is a contact body formed by a cylinder and a cube, the contact area is a rectangle, and the contact area is equal to the determined contact width multiplied by the length of the cylinder.

The present invention also provides a contact area measurement system based on image measurement technology. The system cooperates with the contact body to measure the contact area between the contact bodies. The system includes: a backlight module, an image acquisition module and a contact area identification module, in,

The backlight module, coupled to the contact body, is used to provide a uniform light field for the contact body;

The contact body is respectively coupled with the backlight module and the image acquisition module, and is used to form a contact area in the light field of the backlight module, and the image of the contact part is collected by the image acquisition module;

The image acquisition module is respectively coupled to the contact body and the contact area recognition module, and is used to collect the contact part image of the contact body and send it to the contact area recognition module;

The contact area identification module is coupled with the image acquisition module, and is used to receive the image of the contact part sent by the image acquisition module to perform boundary identification to obtain the contact width and calculate the contact area between the contact bodies.

Preferably, the backlight module includes: a light source, a moving aperture and a white screen, wherein,

The light source is coupled to the moving aperture and used to provide light;

The moving aperture is respectively coupled to the light source and the white screen, and is used to adjust the irradiation area of the light source;

The white screen is respectively coupled with the moving aperture and the contact body, and is used to scatter the light to the contact body, and at the same time, the white screen is also used as a white background.

Preferably, the image acquisition module is further provided with a camera, the camera is respectively coupled with the contact body and the contact area recognition module, and is used to collect the image of the contact part of the contact body and send it to the contact area Identification module.

Preferably, the contact body is further a contact body formed by a cylinder and a cube; or is further a contact body formed by a sphere and a cube.

Preferably, the contact body is further a contact body formed by graphite cylinders and graphite square bricks; or further is a contact body formed by graphite balls and graphite square bricks.

Compared with the prior art, the contact area measurement method and system based on image measurement technology described in this application has the advantages of non-contact, high precision, continuous and high-temperature environment measurement, and can automatically complete various The measurement of the contact area under these working conditions achieves the following effects:

1) The contact area measurement method and system based on image measurement technology provided by the present invention can isolate the measurement system from the object to be measured, thus solving the problem that the contact area cannot be measured under extreme conditions such as high temperature;

2) The contact area measurement method and system based on the image measurement technology provided by the present invention realizes the measurement mode of continuous shooting, and also realizes the real-time acquisition in the loading process;

3) The contact area measurement method and system based on the image measurement technology provided by the present invention, the measurement accuracy can reach the sub-pixel level.

Description of drawings

The drawings described here are used to provide a further understanding of the application and constitute a part of the application. The schematic embodiments and descriptions of the application are used to explain the application and do not constitute an improper limitation to the application. In the attached picture:

Figure 1 is a schematic diagram of point contact and line contact;

Fig. 2 is a schematic flow chart of the contact area measurement method based on the image measurement technology provided by the present invention;

Fig. 3 is a schematic structural diagram of a contact area measurement system based on image measurement technology provided by the present invention;

Fig. 4 is the calibration picture of graphite line contact;

Figure 5 is the image collected by the graphite line contact experiment and the contact body profile after its boundary identification;

Fig. 6 is the variation curve of graphite line contact half-width with load;

Figure 7 is the image collected from the graphite point contact experiment in a high temperature environment and the contour of the contact body after its boundary is identified;

Fig. 8 is the curve of graphite point contact radius changing with load under high temperature environment.

detailed description

Certain terms are used, for example, in the description and claims to refer to particular components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not use the difference in name as a way to distinguish components, but use the difference in function of components as a criterion for distinguishing. As mentioned throughout the specification and claims, "comprising" is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. In addition, the term "coupled" herein includes any direct and indirect electrical coupling means. Therefore, if it is described that a first device is coupled to a second device, it means that the first device may be directly electrically coupled to the second device, or indirectly electrically coupled through other devices or coupling means. connected to the second device. The subsequent description of the specification is a preferred implementation mode for implementing the application, but the description is for the purpose of illustrating the general principle of the application, and is not intended to limit the scope of the application. The scope of protection of the present application should be defined by the appended claims.

The present application will be described in further detail below in conjunction with the accompanying drawings, but it is not intended to limit the present application.

Embodiment one:

In this embodiment, taking the measurement of the contact area between the cylindrical member made of graphite material and the square brick as an example, the specific implementation of the present invention is described in detail, and the specific implementation is as follows:

As shown in Figure 3, this embodiment provides a contact area measurement system based on image measurement technology, the system cooperates with the contact body 302, and is used to measure the contact area between the contact bodies, including: a backlight module 301, an image acquisition module 303 and contact area identification module 304 .

The function of the backlight module 301 is to provide a uniform light field for the contact body 302 . The function of the light source 3011 is to provide light on the back side of the contact body 302 . The moving aperture 3012 is composed of two movable blocking objects, which can reasonably adjust the irradiation area of the light source. The white screen 3013 has two functions. The first is to scatter the light emitted by the light source 3011. The reason for scattering the light is to make the outline of the contact body in the photographed picture clearer, because in the measurement process, the photographed area needs light intensity Evenly distributed light field, for the linear light source provided by LED lamps, no matter how you adjust the light source position and light intensity, it cannot meet the requirements, and this effect can be achieved by scattering the light; the second function is to play The function of a white background cloth makes the color difference of the contact area captured by the camera obvious and the outline clearer. There are two requirements for the white screen 3013. First, the distribution of material properties is uneven. The uneven distribution of material properties here means that the material is not isotropic. Scattering will occur when the screen is white, which can meet the requirements of scattering light, and secondly, the color of the object is white, which can meet the requirements of it as a white background cloth.

The contact body 302 is coupled to the backlight module 301 and the image acquisition module 303 respectively, and is used to form a contact area in the uniform light field of the backlight module 301 , and the image acquisition module 303 collects an image of the contact part. The contact body 302 is further a contact body formed by a cylinder and a cube; or further a contact body formed by a sphere and a cube. In this embodiment, the contact body 302 is a contact body formed by a graphite cylinder and a graphite square brick, and a line contact is formed between the contact bodies. Of course, the form of the contact body 302 is not specifically limited here. The contact body 302 can also be a contact body formed by a triangular pyramid and a plane, or a contact body formed by an elliptical cylinder and a plane, depending on the actual situation.

The image collection module 303 is coupled to the contact body 302 and the contact area identification module 304 respectively, and is used to collect the contact site image of the contact body 302 and send it to the contact area identification module 304 . In this embodiment, a camera 3031 is further provided in the image acquisition module 303, and the further camera 3031 is an IPX-16M3-L high-resolution camera. The function of the image acquisition module 303: to continuously photograph the contact body loaded under the uniform light field to obtain digital image information. Before shooting the contact body 302, the camera and lens used in the module must be adjusted first. In order to meet the requirements of post-processing calculation, it is necessary to accommodate the entire characteristic part of the contact body (such as more than half of a cylinder or sphere) into the in the picture. After selecting the shooting area, adjust the focus so that the contact area presents a clear image. Because the resolution unit of the picture collected by the camera 3031 is a pixel, it is necessary to calibrate the contact area after the image is adjusted to be clear, so that the resolution unit of the collected picture is converted into a standard length unit. After the focal length is adjusted, the aperture should be adjusted as large as possible on the premise that the outline of the contact body 302 can be recognized as a whole. This can increase the light intensity of the background of the white screen 3013, making the gray difference between the contact body 302 and the background more obvious and easy to identify. After the camera lens is adjusted, the camera acquisition speed can be set to collect images in real time during the experiment.

The contact area identification module 304 is coupled with the image acquisition module 303, and is used to receive the image of the contact part sent by the image acquisition module 303 and perform boundary identification to obtain the contact width, and calculate the contact area between the contact bodies. In this embodiment, it is For the contact between a cylinder and a cube, the contact area is a cuboid, and the contact area can be calculated by multiplying the measured contact width by the length of the cylinder. The function of the contact area recognition module 304 is to recognize the boundary of the image collected by the image collection module. In images, boundaries represent the end of one feature region and the start of another feature region. The internal features or attributes of the areas separated by the boundary are consistent, but the internal features or attributes of different areas are quite different. The boundary recognition is realized by using the difference in certain image characteristics between the object and the background. This difference includes grayscale, color, etc. Boundary recognition is really all about detecting where changes in image properties occur. The boundary feature in the present invention is the gray value of the image. The gray value on the bright side of the boundary is relatively large, and the gray value on the other side of the boundary is small. One side of the boundary is the end point of the region with a larger gray value, and the other side is the gray value. The starting point of the region with a small value. The image captured by the camera 3031 is a grayscale image, and the captured image is read into the software to obtain the grayscale value of each pixel. The grayscale value of the contact part is low, while the grayscale value of the white screen 3013 is high, and the grayscale value on both sides of the boundary The difference is huge. After the boundary is identified, the contour of the contact body can be obtained. The "connected" part of the contour is the contact area of the contact object. The contact area between the contact bodies can be obtained through the obtained contact area width (there are two contact bodies, upper and lower. The contact area of the upper contact body and the lower contact body is actually one. When performing boundary recognition on the image, the contour of the upper contact body and the lower contact body will be recognized, and there will be an overlapping area between the two contours are connected together, and this connected part is the contact area of the two contact bodies).

This embodiment also provides a contact area measurement method based on image measurement technology, as shown in Figure 2, the method includes the following steps:

Step 201: the light source provides light, adjusts the light range and scatters the light, and provides a uniform light field for the contact body;

Step 202: loading a contact body to form a contact area;

Step 203: Use a camera to photograph the contact body loaded under a uniform light field, and collect an image of the contact part;

Step 204: Analyzing the image of the contact part, identifying the boundary, determining the contact width, and calculating the contact area between the contact bodies.

In step 204, the contact half-width between the contact bodies can also be obtained as a function of load variation curve.

Step 201 is further: after the light source provides light, use the moving aperture to adjust the irradiation range, use the white screen to scatter the light, and provide a uniform light field for the contact body.

Step 203, further:

The IPX-16M3-L high-resolution camera is used to shoot the contact body loaded under the uniform light field, and the image of the contact part is collected.

Step 204, further:

When the contact body is a contact body formed by a sphere and a cube, the contact area is circular, the determined contact width is the diameter d of the contact area, and the contact area is equal to π×(d/2) ² ;

When the contact body is a contact body formed by a cylinder and a cube, the contact area is a rectangle, and the contact area is equal to the determined contact width multiplied by the length of the cylinder. The size of the graphite cylinder in this embodiment is Φ50×60 mm, and the size of the graphite square brick is 100×100×60 mm. The loading equipment is MTS810 material performance testing machine. Before this embodiment, first set up the light source 3011, moving aperture 3012, and white curtain 3013 in the backlight module. A4 white paper. After the construction of each part of the backlight module 301 is completed, an IPX-16M3-L high-resolution camera is set up on a tripod outside the environmental chamber.

After the camera is set up, enter the image acquisition module 303 . Adjust the focal length of the camera to take a clear picture of the graphite end surface, and paste a calibration paper with scale on the cylinder end surface. At this time, a picture is taken to calibrate the resolution of the object surface. The calibration picture of the graphite contact body 302 is shown in FIG. 4 . After shooting, take off the pasted calibration paper and adjust the camera aperture to the maximum. After the camera is debugged, turn on the testing machine for loading at a loading speed of 0.1mm/min, and at the same time turn on the image acquisition system of the high-resolution camera at an acquisition speed of 0.2fps. When the load reaches 50KN, stop the testing machine loading and camera image acquisition at the same time.

After the image collection in this embodiment is completed, the image collected in this embodiment is imported into the contact area identification module 304, and software is used to identify the boundary of the contact body in the image. In the image obtained after boundary identification, the outline of the contact body is displayed in white, while the remaining area is displayed in black. The intersection point between the boundary of the graphite cylinder and the outline of the graphite brick is the contact point between the two. The image collected in this embodiment and the image after boundary identification The profile of the contact body is shown in Figure 5. The part between the two contact points is the contact width between the graphite cylinder and the graphite brick. The contact area of the graphite line contact can be obtained by obtaining the contact width. Fig. 6 is the change result of the contact half-width during the continuous loading process of the graphite contact body obtained by this embodiment.

Embodiment two:

In this embodiment, taking the measurement of the contact area between a spherical member made of graphite material and a square brick in a high-temperature environment as an example, the specific implementation of the present invention in a high-temperature environment is described in detail.

As shown in Figure 3, this embodiment provides a contact area measurement system based on image measurement technology, the system cooperates with the contact body 302, and is used to measure the contact area between the contact bodies, including: a backlight module 301, an image acquisition module 303 and contact area identification module 304 .

The function of the backlight module 301 is to provide a uniform light field for the contact body 302 . The function of the light source 3011 is to provide light on the back side of the contact body 302 . The moving aperture 3012 is composed of two movable blocking objects, which can reasonably adjust the irradiation area of the light source. The white screen 3013 has two functions. The first is to scatter the light emitted by the light source 3011. The reason for scattering the light is to make the outline of the contact body in the photographed picture clearer, because in the measurement process, the photographed area needs light intensity Evenly distributed light field, for the linear light source provided by LED lamps, no matter how you adjust the light source position and light intensity, it cannot meet the requirements, and this effect can be achieved by scattering the light; the second function is to play The function of a white background cloth makes the color difference of the contact area captured by the camera obvious and the outline clearer. The requirements for the white screen 3013 are the same as those in the first embodiment.

The contact body 302 is coupled to the backlight module 301 and the image acquisition module 303 respectively, and is used to form a contact area in the uniform light field of the backlight module 301 , and the image acquisition module 303 collects an image of the contact part. The contact body 302 is further a contact body formed by a cylinder and a cube, or a contact body formed by a sphere and a cube. In this embodiment, the contact body 302 is a contact body formed by graphite balls and graphite square bricks, and a point contact is formed between the contact bodies. Of course, the form of the contact body 302 is not specifically limited here. The contact body 302 can also be a contact body formed by a triangular pyramid and a plane, or a contact body formed by an elliptical cylinder and a plane, depending on the actual situation.

The image collection module 303 is coupled to the contact body 302 and the contact area identification module 304 respectively, and is used to collect the contact site image of the contact body 302 and send it to the contact area identification module 304 . In this embodiment, a camera 3031 is further provided in the image acquisition module 303, and the further camera 3031 is an IPX-16M3-L high-resolution camera. The function of the image acquisition module 303: to continuously photograph the contact body loaded under the uniform light field to obtain digital image information. Before shooting the contact body 302, the camera and lens used in the module must be adjusted first. In order to meet the requirements of post-processing calculation, it is necessary to accommodate the entire characteristic part of the contact body (such as more than half of a cylinder or sphere) into the in the picture. After selecting the shooting area, adjust the focus so that the contact area presents a clear image. Because the resolution unit of the picture collected by the camera 3031 is a pixel, it is necessary to calibrate the contact area after the image is adjusted to be clear, so that the resolution unit of the collected picture is converted into a standard length unit. After the focal length is adjusted, the aperture should be adjusted as large as possible on the premise that the outline of the contact body 302 can be recognized as a whole. This can increase the light intensity of the background of the white screen 3013, making the gray difference between the contact body 302 and the background more obvious and easy to identify. After the camera lens is adjusted, the camera acquisition speed can be set to collect images in real time during the experiment.

The contact area identification module 304 is coupled with the image acquisition module 303, and is used to receive the contact site image sent by the image acquisition module 303 and perform boundary identification to obtain the contact width, and calculate the contact area between the contact bodies (such as in this embodiment) For the contact between a sphere and a cube, the contact width is actually the diameter d of the contact area (circle), and π×(d/2) ² is the area of the contact area). The function of the contact area recognition module 304 is to recognize the boundary of the image collected by the image collection module. In the image, the boundary represents the end point of a feature area and the starting point of another feature area. The internal features or attributes of the area separated by the boundary are consistent, but the internal features or attributes of different areas are quite different. Boundary recognition It is achieved by using the difference between the object and the background in certain image characteristics. This difference includes grayscale, color, etc. Boundary recognition is really all about detecting where the properties of an image change. The image captured by the camera 3031 is a grayscale image, and the captured image is read into the software to obtain the grayscale value of each pixel. The grayscale value of the contact part is low, while the grayscale value of the white screen 3013 is high, and the grayscale value on both sides of the boundary The difference is huge. After the boundary is identified, the contour of the contact body can be obtained. The "connected" part of the contour is the contact area of the contact object. The contact area between the contact bodies can be obtained through the obtained contact area width (there are two contact bodies, upper and lower. The contact area of the upper contact body and the lower contact body is actually one. When performing boundary recognition on the image, the contour of the upper contact body and the lower contact body will be recognized, and there will be an overlapping area between the two contours are connected together, and this connected part is the contact area of the two contact bodies).

This embodiment also provides a contact area measurement method based on image measurement technology, as shown in Figure 2, the method includes the following steps:

Step 201: the light source provides light, adjusts the light range and scatters the light, and provides a uniform light field for the contact body;

Step 202: loading a contact body to form a contact area;

Step 203: Use a camera to photograph the contact body loaded under a uniform light field, and collect an image of the contact part;

Step 204: Analyzing the image of the contact part, performing boundary recognition, determining the contact width, and then calculating the contact area between the contact bodies.

In step 204, the contact half-width between the contact bodies can also be obtained as a function of load variation curve.

Step 201 is further: after the light source provides light, adjust the light range by moving the aperture, and use the white screen to scatter the light to provide a uniform light field for the contact body.

Step 203, further:

The IPX-16M3-L high-resolution camera is used to shoot the contact body loaded under the uniform light field, and the image of the contact part is collected.

Step 204, further:

When the contact body is a contact body formed by a sphere and a cube, the contact area is circular, the determined contact width is the diameter d of the contact area, and the contact area is equal to π×(d/2) ² ;

When the contact body is a contact body formed by a cylinder and a cube, the contact area is a rectangle, and the contact area is equal to the determined contact width multiplied by the length of the cylinder.

The diameter of graphite balls in this embodiment is 40mm, and the graphite square bricks and loading equipment are the same as those in Embodiment 1. The heating equipment is MTS8651 environment box. In order to ensure the quality of the captured images, the observation window of the environmental chamber uses ultra-clear quartz glass that can withstand high temperatures of 1600 °C. Before the measurement, it is necessary to set up the light source 3011 in the backlight module, the moving aperture 3012 and the white curtain 3013 in the environmental chamber. In this embodiment, the light source 3011 uses a 500-degree high-temperature-resistant lamp, the moving aperture 3012 is composed of a low-carbon steel block wrapped with asbestos, and the white curtain 3013 is made of high-temperature-resistant paper made of ceramic fibers. After the construction of each part of the light source module is completed, set up the IPX-16M3-L high-resolution camera with a tripod outside the environmental chamber.

After setting up the camera, enter the image acquisition module. Turn on the high-temperature-resistant lamp, align the surface of the calibration object prepared in advance with the contact surface, adjust the focal length of the camera to take a clear picture of the surface of the calibration object, and take a picture at this time for calibration object surface resolution. After shooting, take out the calibration object and adjust the camera aperture to the maximum. After the camera is debugged, turn on the heating device of the environmental chamber and raise the temperature to 200°C. When the temperature of the environmental chamber is stable, turn on the testing machine for loading at a loading speed of 0.1mm/min, and at the same time turn on the image acquisition system of the high-resolution camera at an acquisition speed of 0.2fps. When the load reaches 12KN, stop the testing machine loading and camera image acquisition at the same time.

In this embodiment, the flow of the contact area recognition module under high temperature conditions is the same as that of Embodiment 1. Figure 7 shows the image collected by the high temperature experiment and the contact body profile after the boundary recognition of the image, and Figure 8 shows the graphite contact body obtained through the experiment. Variation results of the contact radius during continuous loading.

Compared with the prior art, the contact area measurement method and system based on image measurement technology described in this application has the advantages of non-contact, high precision, continuous and high-temperature environment measurement, and can automatically complete various The measurement of the contact area under these working conditions achieves the following effects:

The contact area measurement method and system based on image measurement technology provided by the present invention can isolate the measurement system from the object to be measured, thus solving the problem that the contact area cannot be measured at high temperature; the contact area based on image measurement technology provided by the present invention The area measurement method and system realizes the measurement mode of continuous shooting, and also realizes the real-time acquisition during the loading process; the contact area measurement method and system based on the image measurement technology provided by the present invention, the measurement accuracy can reach the sub-pixel level.

The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various Various other combinations, modifications and environments, and can be modified by the above teachings or the technology or knowledge in the related field within the scope of the application concept described herein. However, modifications and changes made by those skilled in the art do not depart from the spirit and scope of the present application, and should all be within the protection scope of the appended claims of the present application.

Claims (3)

1. A contact area measurement system based on image measurement technology, the system cooperates with contact bodies to measure the contact area between contact bodies, it is characterized in that, comprising: backlight module, image acquisition module and contact area identification module, in, The backlight module, coupled to the contact body, is used to provide a uniform light field for the contact body; The backlight module includes: a light source, a moving aperture and a white screen, the light source, coupled with the moving aperture, is used to provide light on the back of the contact body, The moving aperture is composed of two movable blocking objects, coupled with the white screen, and used to adjust the irradiation area of the light source, The white screen is used to scatter the light to the contact body, and the white screen is also used as a white background, and the constituent materials of the white screen are mixed with impurities or uneven agglomerates, so that the light Scattering occurs when passing through the white screen; The contact body is respectively coupled with the backlight module and the image acquisition module, and is used to form a contact area in the light field of the backlight module, and the image of the contact part is collected by the image acquisition module; The image acquisition module is respectively coupled to the contact body and the contact area recognition module, and is used to collect the contact part image of the contact body and send it to the contact area recognition module; The contact area identification module is coupled with the image acquisition module, and is used to receive the image of the contact part sent by the image acquisition module to perform boundary identification to obtain the contact width and calculate the contact area between the contact bodies. The gray value is used to obtain the contour of the contact body, and the connected part of the contour is the contact area of the contact body. The contact width is obtained through the contact area, and the contact area between the contact bodies is calculated through the contact width. 2 . The contact area measurement system based on image measurement technology according to claim 1 , wherein the contact body is further a contact body formed by a cylinder and a cube; or is further a contact body formed by a sphere and a cube. 3 . 3. The contact area measurement system based on image measurement technology according to claim 1, characterized in that, the contact body is further a contact body formed by a graphite cylinder and a graphite square brick; or is further a graphite ball and a graphite square brick contacts formed.