Pressure measuring device and system for pressure-sensitive paper

Abstract

According to the pressure measuring device and system for the pressure-sensitive paper provided by the embodiment of the invention, uniform pressure is applied to the pressure-sensitive paper through the pressure applying module and the actual pressure value borne by the sample pressure-sensitive paper, and image data is acquired in an optimized acquisition environment. And constructing a pressure measurement and calculation model by using the corresponding image data, and measuring the image data of the pressure-sensitive paper subjected to pressure in production practice according to the pressure measurement and calculation model to obtain the pressure value of the measured pressure-sensitive paper. According to the system, by optimizing the collection environment, it is ensured that collected image data of sample pressure-sensitive paper and pressure-sensitive paper stressed in production practice are not affected by environmental factors, and the consistency of image data obtained by a computer is guaranteed. Pressure measurement is carried out on the image data through the analysis model, a pressure value is output, the detection precision of pressure measurement is improved, and the efficiency of image acquisition is improved. And the pressure applying module in sampling can ensure the uniformity and consistency of a pressure applying sample. The system can monitor the production process of the pressure-sensitive paper and improve the production efficiency and the yield of products.

Description

Technical Field

[0001] The present application relates to the technical field of pressure-sensitive paper, and in particular to a pressure measuring device and system for pressure-sensitive paper. Background Art

[0002] Pressure-sensitive paper is usually composed of multiple layers, each of which plays a specific role. Figure 1 As shown, pressure-sensitive paper is made of two special materials, L sheet and K sheet. The PET (polyethylene terephthalate) substrate layer in L sheet and K sheet is used as the bottom material to provide stability and support for the entire structure, and the PET substrate layer has a glossy surface treatment; the color-forming layer (a type of coating surface) of the L sheet may change (such as color change) when subjected to pressure or other stimuli, thereby displaying certain information or patterns, and the color-developing layer (a type of coating surface) of the K sheet is the layer that can change color when subjected to external stimuli (such as pressure, temperature, etc.). In pressure-sensitive paper, the color-developing layer usually contains special dyes or pigments, which react with the color-forming layer or other substances when subjected to pressure, thereby displaying colors. Glossy surface usually refers to a treatment method for the surface of a material to give it a smooth and bright appearance.

[0003] The microcapsules carrying the coloring substance on the L sheet break, and the coloring substance reacts chemically with the color developer at the corresponding position on the K sheet, showing red. The degree of microcapsule rupture is determined by the pressure applied. The greater the pressure, the more microcapsules are destroyed and the higher the color density. Conversely, the lower the color density.

[0004] like Figure 2 As shown in the figure, the horizontal axis represents the color gradient and the vertical axis represents the pressure. The ideal pressure-sensitive paper should have a good linear performance of the pressure within its effective working range. Of course, one type of pressure-sensitive paper cannot cover all pressure areas. Often different pressure ranges (such as 0.1MPa~1Mpa, or 1MPa~2.5MPa, etc., 1MPa=10kg / cm 2 ), there are different pressure-sensitive papers corresponding to them, which are divided into different grades.

[0005] Pressure-sensitive paper can well display the pressure applied to the detection surface of the measured object in the form of a two-dimensional distribution. However, due to its own structure, the sensitivity of pressure-sensitive paper to pressure varies greatly due to the influence of the type of microcapsules and the control of the production process. It is also greatly affected by the ambient temperature. Therefore, how to effectively eliminate the influence of various factors to estimate the pressure value more accurately is a difficult problem in the industry. Different products often cannot be estimated using the same color plate or standard value.

[0006] However, traditional pressure-sensitive paper pressure testing relies on the inspector to visually confirm the color concentration and determine whether the surface pressure applied to the inspection surface of the object to be measured is qualified. There is a large error in personal experience and subjective judgment, resulting in low detection accuracy; the previous detection method requires analysis of each piece, and for modern mass production, the data analysis process is boring and time-consuming; the traditional mapping method is greatly affected by environmental factors, resulting in large differences in mapping results and low mapping efficiency; the existing analysis system is often only applicable to the products of specific pressure-sensitive paper manufacturers, limiting the user's choice; there is a lack of effective means to monitor the production stability of pressure-sensitive paper products, which is not conducive to improving product quality. Summary of the invention

[0007] The purpose of the present application is to solve the technical problems of low pressure measurement accuracy and low collection efficiency of pressure-sensitive paper in the prior art. Therefore, the present application provides a pressure measurement device and system for pressure-sensitive paper, which can improve the accuracy, stability and reliability of pressure measurement.

[0008] The present application provides a pressure measuring device for pressure-sensitive paper, comprising:

[0009] A plurality of pressure-sensitive papers in the same group, the pressure-sensitive papers are used to measure pressure values ​​and display colors in response to the pressure values; the plurality of pressure-sensitive papers include sample pressure-sensitive papers and measurement pressure-sensitive papers; the sample pressure-sensitive papers are used to construct a pressure measurement calculation model, and the measurement pressure-sensitive papers are used to measure the pressure value of the external structure;

[0010] Assay components, including:

[0011] Pressure module, image acquisition module, analysis module;

[0012] A pressure module is used to apply pressure to the sample pressure-sensitive paper, so that the force applied to each part of the sample pressure-sensitive paper is the same;

[0013] Obtain the displayed color of the sample pressure-sensitive paper and the corresponding actual pressure value;

[0014] An image acquisition module is used to acquire image data of the sample pressure-sensitive paper and the test pressure-sensitive paper under the same acquisition environment, wherein the image data represents the depth of color displayed by the sample pressure-sensitive paper and the test pressure-sensitive paper;

[0015] The analysis module constructs a pressure measurement calculation model by determining the actual pressure value of the sample pressure-sensitive paper and the corresponding image data, and measures the image data of the pressure-sensitive paper according to the pressure measurement calculation model to obtain the pressure value of the pressure-sensitive paper.

[0016] By adopting the above technical scheme, uniform pressure is applied to the pressure-sensitive paper through the pressure-applying module, and the image data of the sample pressure-sensitive paper and the measurement pressure-sensitive paper are collected under the same collection environment to ensure that the image collection is not affected by environmental factors. Then, the image data is pressure-measured through the analysis module, and the pressure value is output to improve the detection accuracy of the pressure measurement and the efficiency of image collection. The pressure-applying module can ensure the uniformity and consistency of the pressure-applied sample, and the production process of the pressure-sensitive paper can be monitored to improve the production efficiency and the yield rate of the product.

[0017] In some embodiments, a pressure measurement calculation model is constructed using actual pressure values ​​received by the sample pressure-sensitive paper and corresponding image data, and the model parameters of the pressure measurement calculation model are optimized so that the difference between the average pressure value calculated by the pressure measurement calculation model and the actual pressure value is less than a predetermined threshold.

[0018] By adopting the above technical scheme, a pressure measurement calculation model is established according to the actual applied pressure value and image data, and the difference between the average pressure value calculated by the pressure measurement calculation model and the actual pressure value is optimized to be less than a predetermined threshold value. This can reduce the error between the calculated average pressure value and the actual pressure value, improve the accuracy of pressure measurement, and predict the color development of pressure-sensitive paper under different actual pressure values ​​through the pressure measurement calculation model, thereby providing a more reliable reference basis in practical applications.

[0019] In some embodiments, N gradient pressures are applied to the pressure-sensitive paper, and for each gradient pressure value, M sample pressure-sensitive papers are selected to apply pressure according to the gradient pressure value to obtain image data of N*M sample pressure-sensitive papers, where the gradient pressure value represents the actual pressure value, and N and M represent positive integers;

[0020] According to the linear relationship between the color of the pressure-sensitive paper and the pressure value, the image data of N*M sample pressure-sensitive papers and the corresponding N*M calculated pressure values ​​are obtained;

[0021] According to the N*M calculated pressure values, N pressure average values ​​corresponding to the N gradient pressures are obtained;

[0022] According to the average pressure value and the corresponding gradient pressure value, the model parameters of the pressure measurement calculation model are optimized so that the difference between the average pressure value calculated by the pressure measurement calculation model and the actual pressure value is less than a predetermined threshold value, the optimized model parameters are determined, and the final pressure measurement calculation model is obtained.

[0023] By adopting the above technical scheme, by applying gradient pressure to the pressure-sensitive paper and optimizing the model parameters according to the calculated average pressure value and the corresponding gradient pressure value, the relationship between the average pressure value and the applied gradient pressure can be determined. In practical applications, the average pressure value can be determined based on the applied gradient pressure to predict the pressure value of the pressure-sensitive paper, providing strong support for the production and application of pressure-sensitive paper.

[0024] In some embodiments, the model parameters of the pressure measurement calculation model are optimized through statistical software and optimization formulas, the optimized model parameters are determined, and the final pressure measurement calculation model is obtained. The optimization formula represents the value of the model parameter when the difference between the average pressure value calculated by the pressure measurement calculation model and the actual pressure value is minimized.

[0025] By adopting the above technical solution, in practical applications, the model parameters can be optimized by inputting the optimization formula into the statistical software through statistical software, which is simple to operate, efficient and has a wide range of applications.

[0026] In some embodiments, the pressure module includes: a platform, a pressure unit, a control unit and a guide rail;

[0027] A support platform, used for carrying the sample pressure-sensitive paper;

[0028] The pressure-applying unit is slidably connected to the guide rail through the control unit. The control unit slides on the guide rail to drive the pressure-applying unit to move up and down, so that the pressure-applying unit applies pressure to the sample pressure-sensitive paper.

[0029] By adopting the above technical solution, the pressure module applies pressure to the pressure-sensitive paper, and the pressure unit is driven by the control unit and the guide rail to apply pressure to the pressure-sensitive paper, so that the size and time of the applied pressure can be accurately controlled.

[0030] In some embodiments, the control unit is connected to the pressure unit through a universal flange. When the control unit slides on the guide rail and drives the pressure unit to apply pressure to the sample pressure-sensitive paper, the universal flange eliminates the axis deviation of the pressure.

[0031] By adopting the above technical solution, the universal flange is set between the control unit and the pressure unit to eliminate the axial offset force of the applied pressure, so that the pressure on each part of the pressure-sensitive paper is the same, ensuring the uniformity and consistency of the sample pressure-sensitive paper and the test pressure-sensitive paper.

[0032] In some embodiments, the image acquisition module includes: a loading platform, an environment monitoring unit, a light source, an imaging unit, and a motion unit disposed in a light shielding light box;

[0033] A loading platform for placing a plurality of test pressure-sensitive papers;

[0034] The imaging unit is arranged on the moving unit, and the moving unit drives the imaging unit to perform three-dimensional movement to position the pressure-sensitive paper for measurement, and the imaging unit collects image data of the pressure-sensitive paper for measurement;

[0035] The light source provides lighting for the imaging unit, and the environment monitoring unit is used to monitor and measure the collection environment of the image data of the pressure-sensitive paper.

[0036] In some embodiments, after the measuring pressure-sensitive paper to be collected is positioned by a motion unit, the imaging unit is driven by the motion unit to move in a first direction so that the height parameters of the imaging unit are the same when collecting images of multiple measuring pressure-sensitive papers. The first direction represents the direction perpendicular to the plane where the measuring pressure-sensitive paper is located.

[0037] In some embodiments, the environment monitoring unit includes a sensor that acquires temperature data, humidity data, and light intensity data in real time.

[0038] By adopting the above technical scheme, the environmental monitoring unit, light source, imaging unit and motion unit in the image acquisition module can ensure the consistency of the environment during image acquisition, avoid the influence of other factors, ensure the reliability and stability of image acquisition, and can acquire multiple measuring pressure-sensitive papers at one time, thereby improving the acquisition efficiency, and can position the measuring pressure-sensitive papers without confusion; the motion unit drives the imaging unit to move in the first direction to ensure the height parameters during image acquisition, can ensure the height and depth of field of image acquisition, ensure the consistency of the environment when acquiring image data, and thus ensure the accuracy of pressure measurement and reduce errors.

[0039] An embodiment of the present application also provides a pressure measuring system for pressure-sensitive paper, including the pressure measuring device for pressure-sensitive paper mentioned above.

[0040] The embodiment of the present application provides a pressure measurement device and system for pressure-sensitive paper, which applies uniform pressure to the pressure-sensitive paper through a pressure module, and collects image data of the sample pressure-sensitive paper and the measured pressure-sensitive paper under the same collection environment to ensure that the image collection is not affected by environmental factors, and then uses an analysis module to perform pressure measurement on the image data and output a pressure value, thereby improving the detection accuracy of the pressure measurement and the efficiency of image collection. The pressure module can ensure the uniformity and consistency of the pressure sample, and can monitor the production process of the pressure-sensitive paper, thereby improving the production efficiency and the yield rate of the product; the problem of low accuracy of traditional visual inspection by inspectors is solved, and the standardization of the inspection results does not rely on the inspector's judgment, and the repeatability and reproducibility of the measurement system are improved. The image acquisition module can greatly control the acquisition environment and ensure the consistency and efficiency of the acquired images; it can adapt to different standardized pressure-sensitive papers, which enables pressure-sensitive paper user companies to adopt some low-cost but high-quality pressure-sensitive papers, breaking the monopoly of individual companies and providing effective verification and inspection methods for the quality of products of different models; it solves the problem of inconvenient monitoring of the production stability of pressure-sensitive paper products; it can be used for production monitoring of pressure-sensitive paper companies, and can provide companies with effective quantitative analysis methods to improve their product quality; it can be applied to different image acquisition modes to meet the needs of different companies for cost control and utilization of existing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of the structure of a pressure-sensitive paper according to an embodiment of the present application;

[0042] Figure 2 A schematic diagram of a curve showing a linear relationship between color and pressure according to an embodiment of the present application;

[0043] Figure 3 A schematic diagram of the structure of a pressure measuring device for pressure-sensitive paper according to an embodiment of the present application;

[0044] Figure 4 This is a schematic diagram of the structure of a pressure-applying module according to an embodiment of the present application;

[0045] Figure 5 A schematic diagram of a pressure applying unit according to an embodiment of the present application;

[0046] Figure 6 A schematic diagram of an image acquisition module according to an embodiment of the present application;

[0047] Figure 7This is a schematic diagram of the structure of the image acquisition module in an embodiment of the present application;

[0048] Figure 8 A standard sample image reserved for the image acquisition module in the embodiment of the present application for calibration;

[0049] Fig. 9 This is an actual production sample diagram in the embodiment of this application;

[0050] Fig.10 It is a curve fitting diagram of the pressure measurement calculation model of the embodiment of the present application;

[0051] Fig.11 This is a general working flow diagram of the pressure measurement system diagram of an embodiment of the present application;

[0052] Fig.12 A schematic diagram of a flow chart for establishing a pressure measurement calculation model according to an embodiment of the present application;

[0053] Fig.13 A schematic diagram of a process for optimizing parameters of a pressure measurement calculation model according to an embodiment of the present application;

[0054] Fig.14 A schematic diagram of the use process of a pressure measuring device according to an embodiment of the present application;

[0055] Description of reference numerals:

[0056] 100. Pressure measuring device;

[0057] 11. Pressure module;

[0058] 110, support platform; 111, pressure-sensitive paper; 112, pressure-applying unit; 113, control unit; 114, guide rail;

[0059] 12a, image acquisition module;

[0060] 120, loading platform; 121, environmental monitoring unit; 123, light source; 124, imaging unit; 125, motion unit; 126, light shielding light box; c, camera; d, lens;

[0061] 12b. Scanner;

[0062] 13. Analysis module;

[0063] 14. Mobile terminal. DETAILED DESCRIPTION

[0064] The following specific embodiments illustrate the implementation of the present application, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Although the description of the present application will be introduced in conjunction with some embodiments, this does not mean that the features of this application are limited to the implementation. On the contrary, the purpose of introducing the application in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the present application. In order to provide a deep understanding of the present application, the following description will include many specific details. The present application can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present application, some specific details will be omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0065] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0066] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0067] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0068] In the description of the present application, it should be understood that in the present application, "electrical connection" can be understood as physical contact and electrical conduction between components; it can also be understood as a form in which different components in the circuit structure are connected through physical lines such as printed circuit board (PCB) copper foil or wires that can transmit electrical signals. "Coupled through..." can be understood as electrical conduction through air by indirect coupling. Indirect coupling can be understood as contactless coupling, in which it can be understood by those skilled in the art that the coupling phenomenon refers to the phenomenon that there is close cooperation and mutual influence between the input and output of two or more circuit elements or electrical networks, and energy is transmitted from one side to the other through interaction. In order to make the purpose, technical solution and advantages of the present application clearer, the implementation method of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0069] Traditional pressure detection of pressure-sensitive paper relies on the inspector to visually compare the color concentration of the test pressure-sensitive paper with the standard comparison color card to determine whether the surface pressure applied to the inspection surface of the object to be measured is qualified or not. There is a large error in personal experience and subjective judgment, and lack of quantitative analysis, resulting in low detection accuracy, and there is no way to ensure the consistency of judgment under multiple samples; and the simple device of some manufacturers requires analysis of each piece, and the data analysis process is boring and time-consuming, which seriously affects production efficiency; the traditional image collection method is greatly affected by environmental factors, resulting in large differences in image collection results and low efficiency; the existing analysis system is often only applicable to the products of specific pressure-sensitive paper manufacturers, limiting the user's choice range;

[0070] The lack of effective means to monitor the production stability of pressure-sensitive paper products is not conducive to improving product quality.

[0071] Based on the above technical problems, the embodiment of the present application provides a pressure measurement device for pressure-sensitive paper, including: pressure-sensitive paper and a measurement component. Specifically, the same group of multiple pressure-sensitive papers, the pressure-sensitive papers are used to measure pressure values ​​and display colors in response to the pressure values; the multiple pressure-sensitive papers include sample pressure-sensitive papers and measurement pressure-sensitive papers; the sample pressure-sensitive papers are used to construct a pressure measurement calculation model, and the measurement pressure-sensitive papers are used to measure the pressure value of the external structure.

[0072] Among them, the same group of pressure-sensitive papers refers to pressure-sensitive papers with high similarity and small differences, which meet the uniformity requirement. In the embodiment of the present application, there is no restriction on the types of pressure-sensitive papers belonging to the same group. For example, they can be from the same manufacturer, the same specification model, the same batch, etc.

[0073] In the prior art, pressure-sensitive paper has a great difference in sensitivity to pressure due to its own structure, the type of microcapsules, and the control of the production process. It is also greatly affected by the ambient temperature. Therefore, how to effectively eliminate the influence of various factors to estimate the pressure value more accurately is a difficult problem in the industry. Different products often cannot use the same color palette or standard value for estimation, and different products are not compatible with each other.

[0074] The embodiments of the present application can adapt to different standardized pressure-sensitive papers, which enables pressure-sensitive paper user companies to use some low-cost but high-quality pressure-sensitive papers, breaking the monopoly of individual companies and providing effective verification and inspection means for the quality of products of different models.

[0075] Please refer to Figure 3 , Figure 3 FIG. 1 is a schematic diagram of a pressure measuring device 100 for pressure-sensitive paper according to an embodiment of the present application. Figure 3 As shown, the measuring component includes: a pressure module 11, an image acquisition module 12a and an analysis module 13, wherein the analysis module 13 has a communication function and can transmit the collected image data to a mobile terminal 14 (such as a smart phone) in a wired or wireless form, so that the user can flexibly process and evaluate the surface pressure (i.e., the pressure value of the external structure) applied to the inspection surface of the measured object, and finally provide the user with a reference in the form of a report.

[0076] Among them, the pressure application module 11 is used to apply pressure to the sample pressure-sensitive paper, and the force applied to each part of the sample pressure-sensitive paper is the same; the user or the system can obtain the displayed color of the sample pressure-sensitive paper and the corresponding actual pressure value; the image acquisition module 12a is used to collect image data of the sample pressure-sensitive paper and the measured pressure-sensitive paper under the same acquisition environment, and the image data represents the depth of the displayed color of the sample pressure-sensitive paper and the measured pressure-sensitive paper. Figure 3 Shown in FIG. 1 is a schematic diagram of an image acquisition module.

[0077] The analysis module 13 constructs a pressure measurement calculation model by determining the actual pressure value of the sample pressure-sensitive paper and the corresponding image data, and measures the image data of the pressure-sensitive paper according to the pressure measurement calculation model to obtain the pressure value of the pressure-sensitive paper.

[0078] Specifically, the pressure module 11 can control the magnitude of the applied pressure and the time for which the pressure is maintained, and can even monitor the entire process curve of the applied pressure to ensure uniformity and consistency of the standard pressure sample.

[0079] The image acquisition module 12a in the embodiment of the present application can batch-acquire image data of multiple pressure-sensitive papers after the colors are revealed. Compared with the prior art method of acquiring image data through a scanner 12b, the acquisition efficiency is greatly improved. Compared with the scanner method, the acquired image data has high accuracy and small errors. For example, it takes 10 minutes to acquire an image through a scanner, while in the present application, it only takes 3 minutes from the time the image acquisition module 12a acquires the image until the pressure measurement result is obtained, which greatly improves the efficiency, significantly improves the acquisition accuracy, and reduces the error.

[0080] It is known that ordinary cameras have low precision and medium efficiency. Because of differences in height, lighting, etc., the consistency of the photos taken will be relatively weak; Scanner: Because of the line scanning mode and the controlled light source, the precision is higher than that of ordinary cameras, but there is a contradiction between high precision and low efficiency of image acquisition. A good scanner can automatically segment pictures, which will facilitate image acquisition. If multiple samples need to be scanned, the scanning time will be prolonged, and the timeliness of the production site cannot be well met; Mobile camera equipment (mobile phone): The imaging pixels are high, but the consistency is poor. It cannot be used as an ideal image acquisition tool; Industrial camera: Under the condition of defined light source, lens height, etc., the image acquisition efficiency is high and the consistency is strong. Therefore, in the embodiments of the present application, for the efficiency and quality of image acquisition, an industrial camera can be used.

[0081] Furthermore, the analysis module 13 constructs a pressure measurement calculation model according to the actual pressure value and the image data, and optimizes the model according to the actual pressure value to ensure the accuracy of the calculated pressure value of the pressure-sensitive paper.

[0082] In the embodiment of the present application, uniform pressure is applied to the pressure-sensitive paper through a pressure-applying module, and image data of the sample pressure-sensitive paper and the measurement pressure-sensitive paper are collected under the same collection environment to ensure that image collection is not affected by environmental factors. The image data is then pressure-measured through an analysis module to output a pressure value, thereby improving the detection accuracy of the pressure measurement and the efficiency of image collection. The pressure-applying module can ensure the uniformity and consistency of the pressure-applied sample, and can monitor the production process of the pressure-sensitive paper to improve production efficiency and product yield.

[0083] Figure 4 is a schematic diagram of the structure of the pressure module of the embodiment of the present application, such as Figure 4 As shown, the pressure module 11 includes: a base 110, a pressure unit 112, a control unit 113 and a guide rail 114; the base 110 is used to carry the pressure-sensitive paper 111, and the pressure-sensitive paper can be a sample pressure-sensitive paper or a measurement pressure-sensitive paper. In actual applications, the pressure module 11 can be used to apply pressure to the measurement pressure-sensitive paper for testing or production monitoring.

[0084] Optionally, the pressure unit 112 is slidably connected to the guide rail 114 via the control unit 113 , and the control unit 113 slides on the guide rail 114 to drive the pressure unit 1 to move up and down, so that the pressure unit 1 applies pressure to the sample pressure-sensitive paper.

[0085] like Figure 4 As shown, the support platform 110 provides a horizontal surface for placing a pressure measuring sheet (i.e., pressure-sensitive paper), a pressure-applying unit 112 applies a given pressure to the pressure measuring sheet, a control unit 113 can control the pressure magnitude, and a guide rail 114 ensures that the pressure is applied in a consistent direction.

[0086] Specifically, the support platform 110 needs to have good flatness and hardness; when the pressure unit 112 applies pressure to the sample pressure-sensitive paper, it is necessary to ensure that the pressure-sensitive paper is evenly stressed and the pressure is controllable (controlled by a pressure gauge). The pressure unit 112 has a universal flange to ensure that when moving on the guide rail 114, the downward pressure on the pressure unit 112 is uniform and consistent with the plane of the support platform 110. If the user uses many product models, it can also be changed to a high-precision control machine to control the amount of pressure applied and the time the pressure is maintained. It can even monitor the entire process curve of the pressure application to ensure the uniformity and consistency of the standard pressure sample. Exemplarily, standard pressure-sensitive paper can be divided into continuous pressure: the pressure is gradually increased during the pressure application process, the pressure setting value is reached in 5 seconds, and the pressure is maintained for 2 minutes; instantaneous pressure: the pressure is gradually increased during the pressure application process, the pressure setting value is reached in 5 seconds, and the pressure is maintained for 5 seconds.

[0087] Furthermore, Figure 5 is a schematic diagram of a pressure applying unit according to an embodiment of the present application, such as Figure 5 As shown, the material and surface roughness of the pressure unit 112 will have a great influence on the performance of the pressure-sensitive paper 111 after being subjected to pressure, which is determined by the material characteristics of the pressure-sensitive paper 111. Therefore, a suitable pressure unit is selected to ensure that the pressure-sensitive paper 111 is subjected to uniform force and improve the accuracy of pressure measurement.

[0088] The pressure module 11 in the embodiment of the present application applies pressure to the pressure-sensitive paper, and drives the pressure unit 112 to apply pressure to the pressure-sensitive paper 111 through the control unit 113 and the guide rail 114, so that the size and time of the applied pressure can be accurately controlled, and uniform pressure can be ensured. The pressure-sensitive paper is uniformly stressed. Under a known pressure, the pressure-sensitive paper is evenly colored without special blank spaces or areas with intensive stress. At the same time, the effective area is large enough to meet the requirements of image analysis and modeling. Under different pressures, the color difference is obvious.

[0089] Optionally, the control unit 113 is connected to the pressure unit 112 via a universal flange. When the control unit 113 slides on the guide rail 114 and drives the pressure unit 112 to apply pressure to the sample pressure-sensitive paper 111, the universal flange eliminates the axis deviation of the pressure.

[0090] Specifically, by providing a universal flange between the control unit 113 and the pressure-applying unit 112, the axial offset force of the applied pressure is eliminated, so that the pressure on each part of the pressure-sensitive paper is the same, thereby ensuring the uniformity and consistency of the sample pressure-sensitive paper and the measured pressure-sensitive paper.

[0091] Figure 6 is a schematic diagram of an image acquisition module according to an embodiment of the present application, such as Figure 6 As shown, the image acquisition module 12a includes: a loading platform 120 arranged in a light-shielding light box 126, an environment monitoring unit 121, a light source 123, an imaging unit 124 and a motion unit 125.

[0092] Among them, the loading platform 120 is used to place multiple measuring pressure-sensitive papers; the imaging unit 124 is set on the moving unit 125, and the moving unit 125 drives the imaging unit 124 to perform three-dimensional movement to position the measuring pressure-sensitive paper, and the imaging unit 124 collects image data of the measuring pressure-sensitive paper; the light source 123 provides lighting for the imaging unit 124, and the environmental monitoring unit 121 is used to monitor the collection environment of the image data of the measuring pressure-sensitive paper.

[0093] Specifically, multiple pressure-sensitive papers 111 can be placed on a grid-shaped loading platform 120 at the same time. The environmental monitoring unit 121 can monitor the light intensity, ambient temperature and humidity below the camera. The light source 123 is an adjustable and triggerable light source, which provides stable, reliable and consistent lighting during image acquisition. The imaging unit 124 includes a camera c and a lens d. The above parameters need to be consistent with the settings when the pressure measurement calculation model is established and calibrated, and cannot be changed at will. The motion unit 125 can accurately locate the position of the camera during image acquisition to ensure the consistency of the camera during image acquisition (i.e., light intensity and field of view or field of view (FOV)). The light-shielding light box 126 can play a supporting and shading role without being affected by the brightness of the external environment.

[0094] Furthermore, Figure 7 is a schematic diagram of the structure of the image acquisition module of the embodiment of the present application, such as Figure 7 As shown, the imaging unit 124 includes a camera c and a lens d. The light source 123 can be set below the imaging unit 124, and the light source 123 can be set in a circular shape. The light source 123 does not affect the up and down movement of the imaging unit 124. Multiple pressure-sensitive papers 111 can be placed on the loading platform 120 at one time, and the imaging unit can be driven to perform three-dimensional movement through the motion unit 125.

[0095] For example, Figure 7As shown, a motion unit 125 is disposed on the side of the imaging unit 124 to drive the imaging unit 124 to perform two-dimensional motion along the X direction and the Z direction, and a motion unit 125 is disposed at the bottom of the loading platform 120 to drive the imaging unit 124 to perform one-dimensional motion along the Y direction; alternatively, the motion unit 125 can be disposed on the side of the imaging unit 124 to realize driving the imaging unit 124 to perform three-dimensional motion.

[0096] like Figure 6 and Figure 7 As shown, after the measuring pressure-sensitive paper to be collected is positioned by the moving unit 125, the moving unit 125 drives the imaging unit 124 to move in the first direction, so that the height parameters of the imaging unit are the same when collecting images of multiple measuring pressure-sensitive papers. The first direction represents the direction perpendicular to the plane where the measuring pressure-sensitive paper is located (i.e., the Z direction).

[0097] In some optional embodiments, the environment monitoring unit 121 includes a sensor that acquires temperature data, humidity data, and light intensity data in real time.

[0098] In the embodiment of the present application, the environmental monitoring unit 121, the light source 123, the imaging unit 124 and the motion unit 125 in the image acquisition module 12a are used to ensure the consistency of the environment during image acquisition, avoid the influence of other factors, ensure the reliability and stability of image acquisition, and can acquire multiple measuring pressure-sensitive papers at one time, thereby improving the acquisition efficiency, and can position the measuring pressure-sensitive papers without confusion; the imaging unit is driven by the motion unit to move in the first direction to ensure the height parameters during image acquisition, and the height and depth of field of image acquisition can be guaranteed, thereby ensuring the consistency of the environment when acquiring image data, thereby ensuring the accuracy of pressure measurement and reducing errors.

[0099] The embodiment of the present application can automatically sense the position of the pressure-sensitive paper, adjust the position of the camera (lens d) to automatically take pictures, and transmit the corresponding image data of different positions to the storage and computing center of the analysis module 13. The carrier platform 120 has a position mark, which can track the pressure-sensitive paper to ensure the traceability of the pressure-sensitive paper without confusion; it can control the following parameters to ensure the consistency of the image acquisition environment: 1) the consistency of the camera's own parameter settings, 2) the consistency of the imaging environment: including lighting, illumination, 3) the height and depth of field of the camera. The image data with strong consistency is collected to ensure that the pressure measurement calculation model of the analysis module has high accuracy and small errors.

[0100] Figure 8 This is a standard sample image reserved for the image acquisition module for calibration in the embodiment of the present application. Fig. 9 This is an actual production sample diagram in the embodiment of this application. Figure 8As shown in the figure, the sample image requires: under a known pressure, the sample is evenly colored, without any special blanks or areas with intensive force; at the same time, the effective area is large enough to meet the requirements of image analysis and modeling; under different pressures, the color difference is obvious. Fig. 9 As shown, the actual production sample does not have certain properties and uniformity. There may be some places that are not stressed or are heavily stressed, with certain differences. At this time, the image acquisition requires the ability to fully reflect the real situation in the image. Therefore, white balance and effective field of view are very important. For relatively large production samples, you can take multiple shots and then import them into the analysis software in the same batch, so as to ensure the consistency of the analysis results.

[0101] The analysis module 13 in this application is described in detail below. Figure 3 As shown in , the analysis module 13 is provided with a processor and a memory storing reference information corresponding to the measured object. The processor controls the control unit of the image acquisition module 12a and the transmission and acquisition of the two-dimensional image applied to the inspection surface of the measured object; the analysis module 13 also includes a memory, which can save the collected image data and classify it (for example, by channel, time, type, etc.); the analysis module 13 has a communication function, which can transmit the collected image data to a mobile terminal 14 (such as a smart phone) in a wired or wireless form, so that the user can flexibly process and evaluate the surface pressure applied to the inspection surface of the measured object, and finally provide the user with a report for reference; the analysis module 13 has the function of carrying data processing software, and the collected image data needs to be processed by software with a specific algorithm to provide effective pressure distribution information and data statistics.

[0102] The following is a detailed description of the process in which the analysis module 13 in the embodiment of the present application determines the actual pressure value of the sample pressure-sensitive paper and the corresponding image data, constructs a pressure measurement calculation model, and measures the image data of the pressure-sensitive paper according to the pressure measurement calculation model to obtain the pressure value of the pressure-sensitive paper.

[0103] Optionally, a pressure measurement calculation model is constructed using the actual pressure value exerted on the sample pressure-sensitive paper and the corresponding image data, and the model parameters of the pressure measurement calculation model are optimized so that the difference between the average pressure value calculated by the pressure measurement calculation model and the actual pressure value is less than a predetermined threshold.

[0104] Specifically, an appropriate amount of sample pressure-sensitive paper is selected, an actual pressure value is applied to the sample pressure-sensitive paper to obtain image data, an average pressure value corresponding to the image data is obtained through a pressure measurement calculation model, and the model parameters of the pressure measurement calculation model are optimized according to the pressure average value and the actual pressure value to obtain a final pressure measurement calculation model so that the difference between the average pressure value calculated by the pressure measurement calculation model and the actual pressure value is less than a predetermined threshold.

[0105] Exemplarily, N gradient pressures are applied to the pressure-sensitive paper. For each gradient pressure value, M sample pressure-sensitive papers are selected and pressure is applied according to the gradient pressure value to obtain image data of N*M sample pressure-sensitive papers, where the gradient pressure value represents the actual pressure value, and N and M represent positive integers. Based on the linear relationship between the color displayed by the pressure-sensitive paper and the pressure value, the image data of N*M sample pressure-sensitive papers and the corresponding N*M calculated pressure values ​​are obtained. Based on the N*M calculated pressure values, N pressure average values ​​corresponding to the N gradient pressures are obtained. Based on the pressure average values ​​and the corresponding gradient pressure values, the model parameters of the pressure measurement calculation model are optimized so that the difference between the pressure average value calculated by the pressure measurement calculation model and the actual pressure value is less than a predetermined threshold value, the optimized model parameters are determined, and the final pressure measurement calculation model is obtained.

[0106] In the embodiments of the present application, there is no limitation on the specific form of the gradient pressure. The gradient value of the gradient pressure should be arranged according to a certain rule (such as linear, logarithmic, exponential, etc.), and the size of each gradient value should be clearly recorded.

[0107] In an embodiment of the present application, a pressure measurement calculation model is established based on the actual applied pressure value and image data, and the difference between the average pressure value calculated by the pressure measurement calculation model and the actual pressure value is optimized to be less than a predetermined threshold value, thereby reducing the error between the calculated average pressure value and the actual pressure value, improving the accuracy of pressure measurement, and predicting the color development of pressure-sensitive paper under different actual pressure values ​​through the pressure measurement calculation model, thereby providing a more reliable reference basis in practical applications; and by applying gradient pressure to the pressure-sensitive paper and optimizing the model parameters based on the calculated average pressure value and the corresponding gradient pressure value, the relationship between the average pressure value and the applied gradient pressure can be determined. In practical applications, the average pressure value can be determined based on the applied gradient pressure to predict the pressure value to which the pressure-sensitive paper is subjected, thereby providing strong support for the production and application of pressure-sensitive paper.

[0108] Furthermore, the model parameters of the pressure measurement calculation model are optimized through statistical software and optimization formulas, the optimized model parameters are determined, and the final pressure measurement calculation model is obtained. The optimization formula represents the value of the model parameter when the difference between the average pressure value calculated by the pressure measurement calculation model and the actual pressure value is minimized.

[0109] In practical applications, statistical software can be used to optimize model parameters by inputting optimization formulas into the statistical software. This method is simple to operate, efficient and has a wide range of uses.

[0110] In the process of measuring the pressure of pressure-sensitive paper, it is necessary to measure the pressure value of the external structure of the pressure-sensitive paper to detect whether the external structure meets the requirements. However, manufacturers of pressure-sensitive paper generally provide users with standard color cards to determine the pressure of the pressure-sensitive paper. However, due to the image acquisition environment and artificial visual errors, users cannot obtain accurate pressure values ​​when using it. Therefore, in the prior art, since it is impossible to obtain the linear relationship between the color displayed by the standard pressure-sensitive paper and the received pressure value, the accuracy of pressure-sensitive paper measurement is poor and the error is high.

[0111] Optionally, a linear relationship between the displayed color and the pressure value is established, and after the actual pressure value is applied by the above-mentioned pressure-applying unit, a sample pressure-sensitive paper is obtained, and the corresponding image data is used to obtain the corresponding calculated pressure value according to the linear relationship, and the pressure average value of the calculated pressure value is obtained. The parameters in the linear relationship are optimized according to the pressure average value and the actual pressure value to obtain an optimized linear relationship. Thereafter, the optimized linear relationship is used to measure the pressure value of the pressure-sensitive paper, which can improve accuracy and reduce errors.

[0112] The parameters may be optimized by least square method, maximum likelihood estimation or other optimization methods so that the error between the average pressure value and the actual pressure value is less than a preset threshold value. For example, the preset threshold value may be 5% of the actual pressure value.

[0113] It is known that there is a linear relationship between the color and pressure of pressure-sensitive paper. The color depth of pressure-sensitive paper after color development can reflect the magnitude P of the applied pressure, and the color depth is linearly related to the pressure magnitude. Due to the existence of systematic errors and random errors, although the color depth is linearly related to the pressure magnitude, the theoretical calculated pressure value is not directly proportional to the color depth, but there is an error. This error includes systematic error constants and random errors. Systematic errors may come from batch differences in drawing, analysis or pressure-sensitive paper itself. Random errors may be caused by a variety of uncontrollable factors, such as ambient temperature, humidity, etc. By optimizing parameters, the difference between the theoretical calculated pressure value and the actual pressure value can be reduced, thereby improving the accuracy of the pressure measurement calculation model. The pressure measurement calculation model can fit the linear relationship curve between the average pressure value and the actual pressure value, and a more accurate pressure measurement calculation model can be established, which can be used to predict the color development of pressure-sensitive paper under different actual pressure values, thereby providing a more reliable reference basis in practical applications.

[0114] Optionally, according to the linear relationship between the displayed color and the pressure value (pressure measurement calculation model), after applying the actual pressure value through the above-mentioned pressure-applying unit, the sample pressure-sensitive paper is obtained, the corresponding image data is obtained according to the linear relationship The corresponding calculated pressure value, and the pressure average value of the calculated pressure value is obtained. Since there is a linear relationship between the displayed color and the pressure value, there is also a linear relationship between the actual pressure value and the displayed color, but the slope and the intercept are different. Therefore, a linear relationship between the actual pressure value and the calculated pressure value is established (pressure measurement calculation model), and the pressure average value is obtained according to the calculated pressure value. Then, the model parameters in the linear relationship are optimized according to the pressure average value and the actual pressure value to obtain an optimized pressure measurement calculation model, and then the optimized pressure measurement calculation model is used to measure the pressure value of the pressure-sensitive paper.

[0115] Specifically, by comparing the difference between the fitting curve and the actual pressure value, the response performance of the pressure-sensitive paper to different pressures can be evaluated. If the fitting curve is highly consistent with the actual pressure value, it means that the color rendering performance of the pressure-sensitive paper is stable and can accurately reflect the pressure intensity. On the contrary, if the fitting curve is significantly different from the actual pressure value, it may mean that there are batch differences in the pressure-sensitive paper or the color rendering performance is unstable, which requires further improvement or screening.

[0116] The embodiment of the present application can also perform press calibration and optimization, and the fitting curve (fitting curve of the pressure measurement calculation model) can be used as a reference for press calibration. By comparing the difference between the fitting curve and the actual pressure value, the setting parameters of the press can be adjusted to make the pressure applied more accurate and stable. The fitting curve can also be used to optimize the control algorithm of the press to improve the accuracy and stability of pressure control. In the production process of pressure-sensitive paper, the fitting curve can be used to control and monitor the product quality. By real-time monitoring of the difference between the fitting curve and the actual pressure value, problems in the production process, such as unstable quality of pressure-sensitive paper, press failure, etc., can be discovered in time, and corresponding measures can be taken to correct them. The fitting curve can also be used to establish a quality traceability system, trace the source of product quality problems, and provide a basis for quality improvement. In addition, by comparing the difference between the predicted value of the pressure measurement calculation model and the actual pressure value, the accuracy and applicability of the corresponding model can be evaluated. The fitting curve of the pressure measurement calculation model also has a wide range of application value in the fields of scientific research and product development. For example, when developing a new type of pressure-sensitive paper or pressure sensor, the fitting curve can be used to evaluate the performance differences of different materials, providing a basis for material selection and performance optimization. In addition, the pressure measurement calculation model can also be used to study the relationship between pressure and the color development performance of pressure-sensitive paper, providing experimental data support for a deeper understanding of the color development mechanism of pressure-sensitive paper. By comparing the fitting curves and model parameters of different batches of pressure-sensitive paper, their consistency can be evaluated. The pressure intensity of the actual pressure value applied can be estimated by the color depth of the pressure-sensitive paper, which can be used for the calibration and verification of pressure measurement equipment.

[0117] The establishment of the pressure measurement calculation model in this application is described below with a specific embodiment.

[0118] Prerequisites for establishing the pressure measurement calculation model:

[0119] 1) Define the parameter related to the color depth as ρ. The color depth of a good quality pressure-sensitive paper after color development can reflect the magnitude of the pressure applied to it, and the color depth is linearly related to the pressure (a type of pressure value) P = kρ

[0120] 2) The image acquisition module can truly convert the color depth of the pressure-sensitive paper into a digital image (image data), and the calculated pressure calculated by the analysis module is Y;

[0121] 3) There are differences in batches of pressure-sensitive paper products, and the pressure actually applied to the pressure-sensitive paper by the set press machine will also be different each time, and it will not be the same every time. The theoretical value calculated by the color depth of the pressure-sensitive paper will be different from the actual set pressure value;

[0122] 4) The theoretically calculated pressure Y is not directly proportional to the color depth, but has an error. This error has a systematic error constant b and a random error E; therefore, this relationship can be expressed as Y = k*ρ + B + E (1).

[0123] Based on the premise of the above model establishment, the following definition is made: the set pressure intensity (actual pressure value) applied to the pressure-sensitive paper is P = (P1, P2, P3, ..., P N ), and P1 is the minimum value, P N is the maximum value, any one of which has a pressure of P i . Each group pressure P i M samples will be made, and the pressure of the rth sample corresponding to each group of samples calculated by the software is Y ir , where Y i =(Y i1 ,Y i2 ,...,Y iM ), the average value is As shown in Table 1, after completing all the tests, N*M groups of data (Pi, Yi) can be obtained. According to formula (2), Y i and ρ i Linear correlation, where E i Represents the i-th random error:

[0124] Y i =k*ρ i +B+E i ; (2)

[0125] (Linear correlation), then Pi and Yi also have a similar linear relationship, as shown in formula (3):

[0126] Y i =K*P i +b+e i ; (3)

[0127] Among them, the random error e i The goal of this application is to optimize the values ​​of K and b so that the average value The difference with the actual pressure Pi is the smallest, and this difference is calculated using the least squares method, as shown in formula (4):

[0128]

[0129] make Now, we can use formula (2) to find K and b so that L is minimum.

[0130]

[0131] K (such as formula (3)) and b (such as formula (4)) can be obtained by formula (2).

[0132]

[0133] In actual work, you can use an Excel spreadsheet (as shown in Table 1) to input formula (4) for automatic calculation.

[0134] Table 1

[0135]

[0136] By adjusting the values ​​of K and b in groups 1-2, the pressure measurement calculation model can be optimized so that the relative difference between the average pressure value of each group of calculated pressure values ​​and the actual pressure value is kept within 5%, thus establishing the pressure measurement calculation model.

[0137] In actual practice, by adjusting the model parameters through K and b calculations in the software, and then exporting the batch output values, a more optimized result can be obtained.

[0138] Fig.10 The curve fitting diagram of the pressure measurement calculation model of the embodiment of the present application is shown as follows: Fig.10 As shown, the X-axis is the actual pressure value P i (Mpa), the Y axis is the calculated pressure value Y calculated for each group of samples i The blue dots are the average pressure values ​​corresponding to each pressure level. The blue slash is the pressure measurement calculation model obtained by interpolation calculation (Y=K*P+b). The pressure characteristics of high-quality pressure-sensitive paper reflect a typical linear relationship.

[0139] Below through Figure 11-Figure 14 , the establishment and use of the pressure measurement calculation model in the embodiments of the present application are explained.

[0140] Fig.11 The overall working flow diagram of the pressure measurement system of the embodiment of the present application is as follows: Fig.11 As shown, the image acquisition environment settings include camera position, light source parameters, camera parameters, etc. After the settings are completed, the consistency of the image acquisition environment can be guaranteed. At the same time, the sample pressure-sensitive paper or the measurement pressure-sensitive paper is placed in the image acquisition module for image acquisition, and the image is stored and processed in the image processing software to obtain image data and export batch processing results. The establishment process of the pressure measurement calculation model in the embodiment of the present application is as follows Fig.12As shown, the image acquisition environment is set up, and the sample pressure-sensitive paper is obtained through the pressure-applying module. Specifically, the sample pressure-sensitive paper can be obtained by applying gradient pressure to the standard paper sample, and the sample pressure-sensitive paper is subjected to image acquisition in the image acquisition module. The color image can also be classified and stored for later tracing. The color image is processed into image data through image processing software, and the pressure measurement calculation model is calibrated through the image data. After the final pressure measurement calculation model is obtained, the model data is saved.

[0141] Further, such as Fig.13 As shown, the analysis module establishes a pressure measurement calculation model through image data, obtains image data (pictures) from the image acquisition module, and then annotates, stores and imports the pictures, such as Fig.10 As shown in the figure, the minimum pressure fitting and the maximum pressure fitting are performed, and the error analysis results are fed back. After multiple fittings, the optimized pressure measurement calculation model is obtained and saved. Fig.14 As shown, after the program is opened, the engineer first updates the database and sets the parameters. For example, parameters are selected for temperature, humidity and illumination, and the parameter data is input to establish a pressure measurement calculation model. After that, the operator uses the pressure measurement calculation model to read the pressure and enters the pressure reading mode. After selecting parameters such as temperature, humidity, illumination, manufacturer and model, the image data to be measured is input to obtain a pressure report. The report content may include mean, maximum value, abnormal points, etc.

[0142] An embodiment of the present application also provides a pressure measuring system for pressure-sensitive paper, including the pressure measuring device for pressure-sensitive paper mentioned above.

[0143] The embodiment of the present application provides a pressure measuring device and system for pressure-sensitive paper, which applies uniform pressure to the pressure-sensitive paper through a pressure-applying module, and collects image data of the sample pressure-sensitive paper and the measured pressure-sensitive paper under the same collection environment to ensure that the image collection is not affected by environmental factors. Then, the image data is pressure-measured through an analysis module to output a pressure value, thereby improving the detection accuracy of the pressure measurement and the efficiency of image collection. The pressure-applying module can ensure the uniformity and consistency of the pressure-applied sample, and can monitor the production process of the pressure-sensitive paper to improve production efficiency and product yield.

[0144] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and modifications of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and modifications.

Claims

1. A pressure measuring device for pressure-sensitive paper, characterized in that: include: A plurality of pressure-sensitive papers of the same group, the pressure-sensitive papers being used to measure pressure values ​​and to develop colors in response to the pressure values; the plurality of pressure-sensitive papers comprising sample pressure-sensitive papers and measurement pressure-sensitive papers; The sample pressure-sensitive paper is used to construct a pressure measurement calculation model, and the measurement pressure-sensitive paper is used to measure the pressure value of the external structure; Assay components, including: Pressure module, image acquisition module, analysis module; The pressure module is used to apply pressure to the sample pressure-sensitive paper, and the force applied to each part of the sample pressure-sensitive paper is the same; Obtaining the displayed color of the sample pressure-sensitive paper and the corresponding actual pressure value; The image acquisition module is used to acquire image data of the sample pressure-sensitive paper and the measurement pressure-sensitive paper under the same acquisition environment, wherein the image data represents the depth of color displayed by the sample pressure-sensitive paper and the measurement pressure-sensitive paper; The analysis module constructs a pressure measurement calculation model by determining the actual pressure value of the sample pressure-sensitive paper and the corresponding image data, and measures the image data of the measurement pressure-sensitive paper according to the pressure measurement calculation model to obtain the pressure value of the measurement pressure-sensitive paper.

2. The pressure measuring device for pressure-sensitive paper according to claim 1, characterized in that: The pressure measurement calculation model is constructed based on the actual pressure value of the sample pressure-sensitive paper and the corresponding image data, and the model parameters of the pressure measurement calculation model are optimized so that the difference between the average pressure value calculated by the pressure measurement calculation model and the actual pressure value is less than a predetermined threshold.

3. The pressure measuring device for pressure-sensitive paper according to claim 2, characterized in that: Applying N gradient pressures to the pressure-sensitive paper, for each gradient pressure value, selecting M sample pressure-sensitive papers to apply pressure according to the gradient pressure value, and obtaining image data of N*M sample pressure-sensitive papers, wherein the gradient pressure value represents the actual pressure value, and N and M represent positive integers; According to the linear relationship between the color of the pressure-sensitive paper and the pressure value, the image data of the N*M sample pressure-sensitive papers and the corresponding N*M calculated pressure values ​​are obtained; Obtaining N pressure average values ​​corresponding to the N gradient pressures according to the N*M calculated pressure values; According to the pressure average value and the corresponding gradient pressure value, the model parameters of the pressure measurement calculation model are optimized so that the difference between the pressure average value calculated by the pressure measurement calculation model and the actual pressure value is less than a predetermined threshold value, and the optimized model parameters are determined to obtain the final pressure measurement calculation model.

4. The pressure measuring device for pressure-sensitive paper according to claim 3, characterized in that: The model parameters of the pressure measurement calculation model are optimized through statistical software and optimization formulas, the optimized model parameters are determined, and the final pressure measurement calculation model is obtained. The optimization formula represents the value of the model parameter when the difference between the average pressure value calculated by the pressure measurement calculation model and the actual pressure value is minimized.

5. The pressure measuring device for pressure-sensitive paper according to claim 1, characterized in that: The pressure module comprises: a support platform, a pressure unit, a control unit and a guide rail; The support platform is used to support the sample pressure-sensitive paper; The pressure-applying unit is slidably connected to the guide rail via the control unit. The control unit slides on the guide rail to drive the pressure-applying unit to move up and down, so that the pressure-applying unit applies pressure to the sample pressure-sensitive paper.

6. The pressure measuring device for pressure-sensitive paper according to claim 5, characterized in that: The control unit is connected to the pressure unit via a universal flange. When the control unit slides on the guide rail and drives the pressure unit to apply pressure to the sample pressure-sensitive paper, the axis deviation of the pressure is eliminated via the universal flange.

7. The pressure measuring device for pressure-sensitive paper according to claim 1, characterized in that: The image acquisition module includes: a loading platform, an environment monitoring unit, a light source, an imaging unit and a motion unit arranged in a light-shielding light box; The loading platform is used to place a plurality of the measurement pressure-sensitive papers; The imaging unit is arranged on the moving unit, the moving unit drives the imaging unit to perform three-dimensional movement to position the measuring pressure-sensitive paper, and the imaging unit collects image data of the measuring pressure-sensitive paper; The light source provides lighting for the imaging unit, and the environment monitoring unit is used to monitor the collection environment of the image data of the pressure-sensitive paper.

8. The pressure measuring device for pressure-sensitive paper according to claim 7, characterized in that: After the measuring pressure-sensitive paper to be collected is positioned by the moving unit, the imaging unit is driven by the moving unit to move in the first direction so that the height parameters of the imaging unit are the same when collecting images of the multiple measuring pressure-sensitive papers. The first direction represents the direction perpendicular to the plane where the measuring pressure-sensitive paper is located.

9. The pressure measuring device for pressure-sensitive paper according to claim 8, characterized in that: The environmental monitoring unit includes a sensor for acquiring temperature data, humidity data and light intensity data in real time.

10. A pressure measuring system for pressure-sensitive paper, characterized in that: A pressure measuring device comprising the pressure-sensitive paper according to any one of claims 1 to 9.

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