Burette reading calibration method and device, experimental instrument equipment and storage medium

Abstract

The invention relates to a burette reading calibration method and device, experimental instrument equipment and a computer equipment storage medium. The method comprises the following steps: shooting a liquid level change image of the burette in real time by using a camera; the liquid level position is recognized from the liquid level change image according to the optical coding mark, and the lowest point of the liquid level concave surface and the corresponding observation reading are determined according to the liquid level position; calculating a relative position and a shooting angle between the camera and the burette according to the liquid level change image, camera parameters of the camera and instrument parameters of the burette; correcting the observation reading according to the refractive index parameter of the burette wall, the relative position and the shooting angle to obtain a calibration reading; burette reading information is generated according to the calibration reading, and the burette reading information is displayed at the liquid level position; according to the technical scheme, the teaching efficiency and effect of the titration experiment are improved.

Description

Technical Field

[0001] The present application relates to the field of computer technology, and in particular to a method and device for calibrating burette readings, experimental instruments and equipment, and a computer equipment storage medium. Background Art

[0002] The burette is an important instrument in chemical experiments. In the laboratory environment, accurate burette reading is a key step in chemical analysis. Conventional burette reading methods mainly rely on manual operation. The burette liquid level reading requires visual observation of the lowest point of the concave meniscus. Due to the influence of the operator's perspective (looking down / upward) and ambient light, the general error range can reach ±0.05mL. In addition, burettes made of different materials (such as glass and plastic) require the operator to adjust the reading compensation due to the difference in refractive index, which can easily lead to reading deviation.

[0003] In experimental teaching, teachers need to repeatedly guide students to correct their reading methods and constantly calibrate the burette readings, which makes standardization difficult to achieve and takes up a lot of teaching time. In addition, there are parallax errors, which seriously affect teaching efficiency and effectiveness. Summary of the Invention

[0004] In order to solve one of the above-mentioned defects, the present application provides a method and device for calibrating burette readings, experimental instruments and equipment, and computer equipment storage medium to improve the teaching efficiency and effect of titration experiments.

[0005] A method for calibrating a burette reading, comprising:

[0006] Using a camera to capture real-time images of the liquid level changes in the burette; wherein the burette is provided with an optical coding mark;

[0007] identifying a liquid level position from the liquid level change image according to the optical coding mark, and determining the lowest point of the concave surface of the liquid surface and its corresponding observation reading according to the liquid level position;

[0008] Calculating the relative position and shooting angle between the camera and the burette according to the liquid level change image, the camera parameters of the camera, and the instrument parameters of the burette;

[0009] Correcting the observed reading according to the refractive index parameter of the burette wall, the relative position, and the shooting angle to obtain a calibration reading;

[0010] Burette reading information is generated based on the calibration reading and displayed at the liquid level position.

[0011] In one embodiment, identifying the liquid level position from the liquid level change image according to the optical coding mark, and determining the lowest point of the concave liquid surface and its corresponding observation reading according to the liquid level position include:

[0012] Obtain each frame of liquid level change image captured by the camera, and input the liquid level change image into a pre-trained deep learning model to obtain the liquid level position;

[0013] Performing edge detection on the liquid surface position to identify a concave line of the liquid surface;

[0014] The observation reading is determined based on the lowest point of the concave line of the liquid surface and the scale line of the burette.

[0015] In one embodiment, calculating the relative position and shooting angle between the camera and the burette according to the liquid level change image, the camera parameters of the camera, and the instrument parameters of the burette includes:

[0016] Identifying a burette image from the liquid level change image; wherein the burette image includes an image of all or part of the burette;

[0017] Obtaining camera parameters of the camera; wherein the camera parameters include focal length, principal point coordinates and distortion coefficient;

[0018] Obtaining instrument parameters of the burette; wherein the instrument parameters include the size and capacity of the burette;

[0019] The coordinate parameters of the reference point on the burette image are determined according to the instrument parameters, and the relative position and shooting angle between the camera and the burette are calculated according to the coordinate parameters and the camera parameters.

[0020] In one embodiment, determining the coordinate parameters of a reference point on the burette image according to the instrument parameters, and calculating the relative position and shooting angle between the camera and the burette according to the coordinate parameters and the camera parameters, includes:

[0021] Selecting a plurality of reference points on the burette image;

[0022] Determine the first coordinate of each reference point on the coordinate system according to the instrument parameters;

[0023] The rotation matrix and translation vector of the camera are calculated according to the first coordinates and the camera parameters, and the relative position and shooting angle between the camera and the burette are determined according to the rotation matrix and the translation vector.

[0024] In one embodiment, the observed reading is corrected to obtain a calibration reading according to the refractive index parameter of the burette wall and the relative position and shooting angle, comprising:

[0025] Obtaining a second coordinate of the liquid level position on the coordinate system;

[0026] Acquire a third coordinate of the camera on the coordinate system according to the relative position;

[0027] Determine the refractive index parameter of the burette wall according to the material used for the burette;

[0028] An optical path model is constructed according to the shooting angle, the second coordinate, the third coordinate and the refractive index parameter, and a calibration reading of the burette is obtained by performing tube wall refractive index compensation on the observed reading according to the optical path model.

[0029] In one embodiment, generating burette reading information based on the calibration reading and displaying the burette reading information at the liquid level position includes:

[0030] Generate corresponding burette reading information from the calibration reading of each frame of liquid level change image;

[0031] using tracking technology to identify the optical coding mark and determine the target display position of the burette reading information;

[0032] The burette reading information is displayed according to the target display position.

[0033] In one embodiment, the method for calibrating the burette reading further comprises:

[0034] Obtaining corresponding solution parameters based on calibration readings identified in each frame of liquid level change image;

[0035] Fitting a titration curve on a titration curve graph according to the calibration readings and their corresponding solution parameters;

[0036] The titration curve is dynamically displayed on a display interface.

[0037] In one embodiment, the method for calibrating the burette reading further comprises:

[0038] A camera is used to capture the reading image of the potentiometric titrator in real time, and the corresponding reading is identified from the reading image; when the reading reaches the titration end point, a titration end point prompt is generated, and the reading image and the titration end point prompt are displayed in real time.

[0039] In one embodiment, the method for calibrating the burette reading further comprises:

[0040] A camera is used to capture an image of the sample solution in the conical flask in real time, and the color of the sample solution is identified from the sample solution image. When a color change is detected in the sample solution to which the indicator is added, a titration end point prompt is generated and placed at the position of the conical flask for real-time display.

[0041] A burette reading calibration device comprising:

[0042] An image capture module, configured to capture images of liquid level changes in a burette using a camera in real time; wherein the burette is provided with an optical coding mark;

[0043] a reading recognition module, configured to recognize the liquid level position from the liquid level change image according to the optical coding mark, and determine the lowest point of the concave surface of the liquid surface and its corresponding observation reading according to the liquid level position;

[0044] a viewing angle calculation module, configured to calculate the relative position and shooting angle between the camera and the burette based on the liquid level change image, the camera parameters of the camera, and the instrument parameters of the burette;

[0045] a parameter correction module, configured to correct the observed reading according to the refractive index parameter of the burette wall and the relative position and shooting angle to obtain a calibration reading;

[0046] An information display module is used to generate burette reading information according to the calibration reading and display the burette reading information at the liquid level position.

[0047] An experimental instrument for titration experiments, comprising a burette, a conical flask, a camera, and a terminal device;

[0048] The burette is provided with an optical coding mark for titrating the solution;

[0049] The conical flask is used to carry the sample solution;

[0050] The camera is used to capture images in real time;

[0051] The terminal device is configured to perform the steps of the burette reading calibration method.

[0052] A computer-readable storage medium storing at least one instruction, at least one program, code set, or instruction set, which is loaded and executed by the processor for performing the steps of the calibration method for the burette reading.

[0053] The technical solution of the above embodiment uses a camera to capture an image of the liquid level changes in the burette in real time and identify the liquid level position, determines the lowest point of the concave liquid surface and its corresponding observation reading based on the liquid level position; calculates the viewing angle between the camera and the liquid surface position based on the instrument parameters of the burette and the scale value corresponding to the observation reading; corrects the observation reading based on the refractive index parameters of the burette wall and the viewing angle to obtain a calibration reading and generate burette reading information, and displays the burette reading information at the liquid level position based on the optical coding mark on the burette; this technical solution can automatically and accurately identify the concave liquid surface and calibrate the burette reading in titration experiment teaching, can assist students in reading correctly, and does not require teachers to repeatedly calibrate the burette reading, meets the requirements of laboratory teaching efficiency and operational standardization, and improves the teaching efficiency and effectiveness of titration experiments.

[0054] Additional aspects and advantages of the present application will be given in part in the following description, which will become apparent from the following description, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0056] Figure 1 This is a schematic diagram of an example application scenario of the calibration method for burette readings;

[0057] Figure 2 is a flow chart of a method for calibrating a burette reading according to an embodiment;

[0058] Figure 3 is a schematic diagram of an example observation reading;

[0059] Figure 4 This is a schematic diagram of an example process for determining observation readings;

[0060] Figure 5 The following is a diagram of an example burette image;

[0061] Figure 6 This is a schematic diagram of an example of the refraction effect of the burette wall;

[0062] Figure 7 This is a diagram of an example burette reading information;

[0063] Figure 8 is a schematic diagram of an example titration curve;

[0064] Figure 9 The present invention is a schematic structural diagram of a burette reading calibration device according to an embodiment. DETAILED DESCRIPTION

[0065] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and are not to be construed as limiting the present application.

[0066] Those skilled in the art will understand that, unless otherwise stated, the singular forms "a," "an," "the," and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of this application refers to the presence of the stated features, integers, steps, and operations, but does not preclude the presence or addition of one or more other features, integers, steps, and operations.

[0067] This application aims to solve the defects in the calibration of burette readings in the burette teaching experiment, and proposes a calibration method for burette readings. Figure 1 As shown, Figure 1 This is a schematic diagram of an example of an application scenario of a calibration method for burette readings. As shown in the figure, in the titration experiment teaching scenario, it mainly includes experimental instruments such as burettes and conical flasks. Optical coding marks are printed on the surface of the burettes. In order to avoid interfering with conventional experiments, the optical coding marks can be printed with ultraviolet fluorescent ink. The specific printing shape and area are determined according to the use requirements. In addition, some other related supporting equipment not shown in the figure can also be included. In the technical solution of this application, cameras are used, such as terminal devices such as smart phones, computers, and wearable devices. These can be configured with or connected to cameras for use. For example, the calibration method for burette readings of this application can be configured on the terminal device as a software program (App), so that when titration teaching is carried out, it can assist teachers in calibrating the burette readings for students, so that teachers no longer need to constantly calibrate the burette readings, reduce teaching time waste, and the teaching process can be standardized, improving teaching efficiency and effectiveness. Generally, smart phones, AR glasses or VR wearable devices can be used to use augmented reality (AR) or virtual reality (VR) technology in real time to obtain images that can assist students in reading and observing real-time data changes in experiments.

[0068] refer to Figure 2 As shown, Figure 2 is a flow chart of a method for calibrating a burette reading according to an embodiment, comprising:

[0069] Step S10: Using a camera to capture images of the liquid level changes in the burette in real time.

[0070] For example, a smartphone or wearable device can be used to capture real-time video images of the titration experiment site. The video images include images of the liquid level changes in the burette, images of the titration experiment operation, and real-time images of the conical flask of the sample solution during the titration process.

[0071] Step S20: identifying the liquid level position from the liquid level change image according to the optical coding mark, and determining the lowest point of the concave liquid surface and its corresponding observation reading according to the liquid level position.

[0072] Specifically, the area where the burette is located in the video image can be identified based on the printed optical coding mark; for example, the burette can be quickly and accurately identified from the liquid level change image in a laboratory environment with special lighting requirements using ultraviolet fluorescent ink, and the liquid level position can be identified from the liquid level change image using image processing, and the liquid level position can be determined in combination with the volume scale value on the burette to determine the observation reading corresponding to the lowest point of the concave surface of the liquid surface, such as Figure 3 As shown, Figure 3 This is an example diagram of observation readings, where the scale of the horizontal line coinciding with the lowest point of the concave surface of the liquid surface is the observation reading.

[0073] In one embodiment, the liquid level position is identified from the liquid level change image according to the optical coding mark, and the lowest point of the liquid concave surface and its corresponding observation reading are determined according to the liquid level position, such as Figure 4 As shown, Figure 4 Here is an example diagram of the process of determining observation readings, which may include the following:

[0074] S201, obtaining each frame of liquid level change image captured by a camera, and inputting the liquid level change image into a pre-trained deep learning model to obtain the liquid level position.

[0075] For example, a convolutional neural network can be used to pre-train a deep learning model based on deep learning to identify the liquid level position of the liquid level change image.

[0076] S202: Perform edge detection on the liquid surface position to identify the concave line of the liquid surface.

[0077] Specifically, after the liquid surface position of the liquid surface change image is identified, the liquid surface concave line is identified from the image using an edge detection algorithm.

[0078] S203, determining an observation reading according to the lowest point of the concave surface line of the liquid surface and the scale lines of the burette.

[0079] Specifically, the corresponding observation reading, ie, the titration volume reading, can be determined according to the horizontal correspondence between the lowest point of the concave surface line of the liquid surface and the scale line of the burette.

[0080] Step S30 , calculating the relative position and shooting angle between the camera and the burette according to the liquid level change image, the camera parameters of the camera, and the instrument parameters of the burette.

[0081] In this step, when a camera is used to capture a video image of the burette during the titration process, the camera is positioned at a certain distance from the burette and at a certain shooting angle. The angle here generally refers to the angle between the central axis of the camera and the horizontal line between the center point of the camera and the burette. At this time, an image of the burette is obtained based on the image of the liquid level change. The specific object size of the burette can be obtained through the instrument parameters of the burette. The burette image and its object size, combined with the camera parameters, can be used to calculate the relative position and shooting angle between the camera and the burette.

[0082] In one embodiment, calculating the relative position and shooting angle between the camera and the burette based on the liquid level change image, the camera parameters of the camera, and the instrument parameters of the burette may include:

[0083] S301 , identifying a burette image from the liquid level change image; wherein the burette image includes a full or partial image of the burette.

[0084] For example, the burette image is identified from the liquid level change image. Here, what is needed is to identify the entire or partial image of the burette, and to cut out the identified burette image.

[0085] S302: Obtain camera parameters of the camera.

[0086] Specifically, these camera parameters may include focal length, principal point coordinates, and distortion coefficients. Since the camera parameters of a camera affect the imaging geometry, they can be obtained based on this. For example, smartphones and wearable devices can obtain the camera parameters of the camera, including focal length, principal point coordinates, distortion coefficients, and sensor information.

[0087] S303: Obtain instrument parameters of the burette.

[0088] Specifically, these instrument parameters include the dimensions of the burette, such as outer diameter, length, and capacity; the actual dimensions of the burette can be used as a reference for calculating the relative position and shooting angle between the camera and the burette.

[0089] S304 , determining coordinate parameters of a reference point on the burette image according to the instrument parameters, and calculating a relative position and a shooting angle between the camera and the burette according to the coordinate parameters and camera parameters.

[0090] Specifically, a three-dimensional coordinate system can be established, and for example, a world coordinate system can be used; reference points are selected on the burette, and the coordinate parameters determined by these reference points are combined with the camera parameters and the pixel size of the reference points on the burette image to calculate the camera pose parameters, thereby obtaining the relative position and shooting angle between the camera and the burette.

[0091] In one embodiment, the process of determining the coordinate parameters of the reference point on the burette image according to the instrument parameters, and calculating the relative position and shooting angle between the camera and the burette according to the coordinate parameters and the camera parameters may include the following:

[0092] (1) Select multiple reference points on the burette image.

[0093] Specifically, a section of the burette image of the liquid level change image can be intercepted at the liquid level position, and then the four vertices of the burette image are selected as reference points. Figure 5 As shown, Figure 5 This is a sample burette image diagram. In the figure, four reference points, p1, p2, p3, and p4, are selected.

[0094] (2) Determine the first coordinate of each reference point on the coordinate system based on the instrument parameters.

[0095] Specifically, after selecting the reference points, the coordinate parameters corresponding to each reference point are determined based on the instrument parameters. The inner and outer diameters of the burette are known. The burette is placed vertically when in use. The length corresponding to each scale can be determined by the volume scale value on the burette combined with the inner diameter size. The width value can be determined based on the outer diameter size of the burette, thereby determining the coordinate parameters corresponding to each reference point. For example, Figure 5 In the spatial coordinate system, the relative coordinates of the four reference points p1, p2, p3, and p4 are known, so the actual coordinate parameters of each reference point can be calculated.

[0096] (3) Calculating the rotation matrix and translation vector of the camera according to the first coordinates and camera parameters, and determining the relative position and shooting angle between the camera and the burette according to the rotation matrix and translation vector.

[0097] For example, a section of the burette determined by four reference points p1, p2, p3, and p4 is rectangular, as shown in FIG. Figure 5 As shown in the left figure, since the image of the burette taken by the camera is rotated at a certain angle, the burette formed by the four reference points is an irregular rectangle p1', p2', p3', p4', as shown in Figure 5As shown in the right figure, by solving the correspondence method from 3D to 2D points, such as the PnP (Perspective-n-Point) algorithm, combined with the first coordinate of the known reference point on the burette and the camera parameters, the camera's rotation matrix and translation vector can be calculated. Then, the distance between the camera and the burette is determined based on the translation vector to determine the relative position. The rotation matrix can be converted into Euler angles to obtain the shooting angle between the camera and the burette.

[0098] For example, when the camera is facing the burette, the actual dimensions of the rectangle p1p2p3p4 are known. One side is H, and based on the pixel width h occupied by the rectangle in the image and the camera's focal length f (in pixels), the distance between the camera and the glassware is D = (H × f) / h. At a certain shooting angle α, the relationship between the length H and the pixel width h is D = (H × f × cosα) / h. The camera's central axis is at an angle α with the burette's horizontal line of sight. The rectangle p1p2p3p4 appears as a trapezoid in the image. By establishing a corresponding geometric model based on the ratio and angle of the trapezoid's upper and lower sides, the camera's tilt angle and distance relative to the trapezoid's midpoint can be calculated. Based on the tilt angle and distance, the camera's shooting angle and relative position relative to the burette can be determined.

[0099] In one embodiment, during the titration experiment, the burette is vertically clamped on the bracket, and the correct reading requires the operator to look directly at the concave line of the liquid surface, with the line of sight tangent to the concave surface of the liquid surface. In actual operation, the operator also needs to master the method of looking directly at the concave line of the liquid surface. The technical solution of the present application can further calibrate the observation position. For example, the technical solution of the present application can also include the following:

[0100] The sight deviation angle is calculated based on the first coordinate of the reference point of the burette image and the position of the concave line of the liquid surface in the burette image, the adjustment direction of the camera is calculated based on the deviation angle, and corresponding prompt information is generated for display. Figure 5 In the example, when the four reference points p1', p2', p3', and p4' in the burette image form a regular rectangle, the camera position is completely perpendicular to the burette, and when the concave line of the liquid surface is at the center of the burette image, the central axis of the camera is facing the concave line of the liquid surface. At this time, the observation position is the most accurate observation position. Therefore, the camera position can be used to simulate the observation position of the human eye, and the deviation between the operator's current observation position and the most accurate observation position is calculated in real time. Adjustment prompts (such as up, down, left, right, etc.) are generated for the operator to adjust the observation position and its observation angle. For example, using AR glasses, the operator can adjust the observation position by raising his head, turning his head, etc.

[0101] As in the solution of the above embodiment, the shooting position of the camera is used to simulate the observation position of the human eye, and the image of the burette is used to detect whether the line of sight is tangent to the concave surface line of the liquid surface. This can be used to train students in how to find the correct observation position during teaching, and avoid looking down or up at the burette reading.

[0102] As in the solution of the above embodiment, the coordinate parameters are determined using the instrument parameters of the burette. The relative position and shooting angle between the camera and the burette can be determined by combining the camera parameters and the burette image. When using a smartphone or wearing a wearable device, the relative position and observation angle of the current student observing the burette can be simulated in real time.

[0103] Step S40 , correcting the observed reading according to the refractive index parameter of the burette wall, the relative position, and the shooting angle to obtain a calibration reading.

[0104] In this step, since the burette is mainly made of glass, its wall has a refraction effect, such as Figure 6 middle, Figure 6 This diagram illustrates the refractive effect of a burette wall. The refractive index of the wall affects the reading of the burette. The camera in the diagram simulates the viewing position of the human eye, requiring compensation for the refractive index when calculating the reading. In this application's technical solution, the refractive index parameters of the burette wall are determined based on the burette material. Combined with the relative position and shooting angle between the camera and burette, the observed reading identified from the liquid level change image is corrected for visual errors and compensated for the refractive index to produce a calibrated reading.

[0105] In one embodiment, the observed reading is corrected to obtain a calibration reading according to the refractive index parameter of the burette wall and the relative position and shooting angle, comprising:

[0106] The method comprises the steps of: obtaining a second coordinate of the liquid surface position in a coordinate system; obtaining a third coordinate of the camera in the coordinate system based on the relative position; determining a refractive index parameter of a burette wall based on a material used for the burette; constructing an optical path model based on the shooting angle, the second coordinate, the third coordinate, and the refractive index parameter; and performing wall refractive index compensation on an observed reading based on the optical path model to obtain a calibrated reading of the burette.

[0107] Specifically, such as Figure 6In the figure, after selecting the reference point, the second coordinate P2 of the lowest point of the concave surface of the liquid surface in the coordinate system can be determined according to the scale value of the burette, and the third coordinate P3 of the camera in the coordinate system can be determined according to the relative position between the camera and the burette. Thereafter, an optical path model is constructed according to the shooting angle α, the second coordinate P2, the third coordinate P3, and the refractive index parameter, that is, the optical path model of the light from the bottom of the concave surface line of the liquid surface to the camera. Based on this optical path model, the observed reading can be compensated for the refractive index of the tube wall, thereby obtaining the calibration reading of the burette.

[0108] In the technical solution of the present application, accurate calibration readings are obtained after correction by correcting the intuitively obtained observation readings, and the errors between the readings are presented, thereby allowing students to better grasp the errors in the readings during the titration experiment, thereby enabling students to continuously master the method of accurate reading and avoid errors during the readings.

[0109] Step S50: generating burette reading information according to the calibration reading, and displaying the burette reading information at the liquid level position.

[0110] In this step, the user can visually observe the observation reading of the burette and also obtain accurate calibration readings. Therefore, the required burette reading information can be generated based on the calibration readings. Then, the optical coding mark printed on the burette is used to place the burette reading information to be displayed at the liquid surface position. For example, when using a wearable device, the burette reading information can be displayed at the liquid surface position in real time following the optical coding mark, thereby achieving a follow-up display effect.

[0111] In one embodiment, generating burette reading information based on the calibration reading and displaying the burette reading information at the liquid level position may include:

[0112] S501, generating corresponding burette reading information from the calibration reading of each frame of liquid level change image.

[0113] Specifically, for each frame of the liquid level change image, the calibration reading obtained after correction is generated, and the corresponding burette reading information is generated. For example, the accurate reading value can be directly generated, and the error value between the current directly observed observation reading and the calibration reading can also be generated. Further, other information content related to the reading can also be generated.

[0114] S502: Using tracking technology to identify the optical coding mark and determine the target display position of the burette reading information.

[0115] For example, AR motion tracking technology can be used to identify the optical coding mark printed on the burette in real time, combined with the identified liquid level position, and then the target display position where the burette reading information needs to be displayed is determined based on the optical coding mark.

[0116] S503: Display the burette reading information according to the target display position.

[0117] For example, when using a smartphone, a display interface can be generated based on the image of the liquid level change, and the burette reading information can be superimposed on the display interface according to the target display position for display. When using a wearable device, such as AR glasses, the burette reading information can be projected onto the target display position. The user can observe the burette through the AR glasses and obtain accurate readings and other information related to the readings in real time; Figure 7 As shown, Figure 7 This is an example diagram of burette reading information. If the reading based on direct observation is 1.67ml, and the reading is calibrated after calibration, as shown in the figure: 1.65ml is the actual reading, with an error of 0.02ml. The concave surface of the liquid surface can be automatically identified through a smartphone or wearable device to assist students in reading correctly.

[0118] Since reading is one of the important contents of titration experiments, different teachers have different experiences, so there will be parallax errors. The reading of the liquid level in the burette requires observing the lowest point of the concave surface of the liquid surface with the naked eye. It is affected by the observation angle (such as looking down, looking up, etc.) and ambient light, and the error range is large. During teaching, teachers need to repeatedly guide students to correct their reading methods, which takes up a lot of time, has low teaching efficiency, and is difficult to achieve standardized teaching, making it difficult to ensure teaching quality.

[0119] Based on the solutions of the above embodiments, during the titration experiment, students can use smartphones or wearable devices, etc., and use software to obtain accurate readings of the titration process in real time, avoiding reading deviations caused by adjusting reading compensation; at the same time, in experimental teaching, teachers do not need to repeatedly guide students to correct reading methods and calibrate burette readings. The standardization of reading calibration can be achieved through software recognition, and students can obtain accurate readings in real time, thereby greatly improving the teaching efficiency and effectiveness in titration experiments.

[0120] In one embodiment, in order to further improve the teaching assistance effect, the technical solution of the present application may further include the following steps:

[0121] The corresponding solution parameters are obtained according to the calibration readings identified in each frame of the liquid level change image; a titration curve is fitted on the titration curve graph according to the calibration readings and their corresponding solution parameters; and the titration curve is dynamically displayed on the display interface. Figure 8 As shown, Figure 8 This is a schematic diagram of an example titration curve. The titration curve is obtained by fitting the solution parameter coordinate points calculated in each frame, so that the dynamic change process of the titration curve can be displayed in real time during the titration experiment.

[0122] As in the above-mentioned embodiment, the titration curve and endpoint judgment logic can be automatically calculated and dynamically displayed through a smart phone or wearable device, thereby assisting students in deeply mastering the titration process during the titration experiment, enhancing the training effect of the experiment, and improving the teaching assistance effect.

[0123] In one embodiment, the calibration method of the burette reading of the present application may include the following scheme when dynamically displaying the titration curve:

[0124] A camera is used to capture the reading image of the potentiometric titrator in real time, and the corresponding reading is identified from the reading image; when the reading reaches the titration end point, a titration end point prompt is generated, and the reading image and the titration end point prompt are displayed in real time.

[0125] For example, during the titration process, a camera is used to capture the reading image of the potentiometric titrator in real time to obtain the corresponding reading. When the reading is about to reach the end point, the reading image and the titration end point prompt content are displayed in real time, thereby deepening the students' training effect on the titration experiment process.

[0126] In one embodiment, the burette reading calibration method of the present application may further include the following scheme when dynamically displaying the titration curve:

[0127] A camera is used to capture an image of the sample solution in the conical flask in real time, and the color of the sample solution is identified from the sample solution image. When a color change is detected in the sample solution to which the indicator is added, a titration end point prompt is generated and placed at the position of the conical flask for real-time display.

[0128] For example, during the titration process, the metering point or end point of the titration curve can be calculated based on the color change (indicator color). By displaying relevant prompts in real time according to the color presented in the sample solution, students can be reminded in real time during the titration experiment to pay attention to each key link of the experimental process, thereby improving teaching efficiency and enhancing the titration experiment teaching training effect.

[0129] The following describes an embodiment of the burette reading calibration device of the present application, with reference to Figure 9 , Figure 9 The present invention is a schematic structural diagram of a burette reading calibration device according to an embodiment, comprising:

[0130] An image capturing module 10 is used to capture images of liquid level changes in a burette in real time using a camera; wherein the burette is provided with an optical coding mark;

[0131] a reading recognition module 20 for identifying the liquid level position from the liquid level change image according to the optical coding mark, and determining the lowest point of the concave surface of the liquid surface and its corresponding observation reading according to the liquid level position;

[0132] A viewing angle calculation module 30 is configured to calculate the relative position and shooting angle between the camera and the burette based on the liquid level change image, the camera parameters of the camera, and the instrument parameters of the burette;

[0133] a parameter correction module 40 for correcting the observed reading to obtain a calibration reading according to the refractive index parameter of the burette wall and the relative position and shooting angle;

[0134] The information display module 50 is configured to generate burette reading information based on the calibration reading and display the burette reading information at the liquid level.

[0135] The burette reading calibration device of this embodiment can execute a burette reading calibration method provided in the embodiment of the present application. The implementation principle is similar. The actions performed by each module in the burette reading calibration device in each embodiment of the present application correspond to the steps in the burette reading calibration method in each embodiment of the present application. For the detailed functional description of each module in the burette reading calibration device, please refer to the description of the corresponding burette reading calibration method shown in the previous text, and will not be repeated here.

[0136] The following describes an embodiment of the experimental apparatus.

[0137] The experimental instrument equipment of the present application is used for titration experiments, including: a burette, a conical flask, a camera and a terminal device; wherein the burette is provided with an optical coding mark for titrating the solution; the conical flask is used to hold the sample solution; the camera is used to capture images in real time; the terminal device is configured to execute the steps of the burette reading calibration method of any of the aforementioned embodiments.

[0138] Illustratively, the terminal device of this embodiment can be a smart phone or a wearable device. When in use, students can install the corresponding App tool on the terminal device. During the titration experiment, the camera of the terminal device can be used to shoot the burette in real time. The terminal device can display the observed burette reading image in real time and also display the correct reading. This can train students to read accurately, and the entire reading process can be standardized, which not only reduces the teacher's workload, but also avoids the influence of errors and improves teaching effectiveness.

[0139] Embodiments of computer-readable storage media are described below.

[0140] This application provides a technical solution for a computer-readable storage medium for implementing functions related to a burette reading calibration method. The computer-readable storage medium stores at least one instruction, at least one program, code set, or instruction set, which is loaded by a processor to execute the burette reading calibration method of any embodiment.

[0141] In an exemplary embodiment, the computer-readable storage medium may be a non-transitory computer-readable storage medium including instructions, such as a memory including instructions. For example, the non-transitory computer-readable storage medium may be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like.

[0142] The above description is only part of the implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for calibrating burette readings, characterized in that: include: Using a camera to capture real-time images of the liquid level changes in the burette; wherein the burette is provided with an optical coding mark; identifying a liquid level position from the liquid level change image according to the optical coding mark, and determining the lowest point of the concave surface of the liquid surface and its corresponding observation reading according to the liquid level position; Calculating the relative position and shooting angle between the camera and the burette according to the liquid level change image, the camera parameters of the camera, and the instrument parameters of the burette; Correcting the observed reading according to the refractive index parameter of the burette wall, the relative position, and the shooting angle to obtain a calibration reading; Burette reading information is generated based on the calibration reading and displayed at the liquid level position.

2. The method for calibrating a burette reading according to claim 1, wherein: Identifying the liquid level position from the liquid level change image according to the optical coding mark, and determining the lowest point of the concave surface of the liquid surface and its corresponding observation reading according to the liquid level position, including: Obtain each frame of liquid level change image captured by the camera, and input the liquid level change image into a pre-trained deep learning model to obtain the liquid level position; Performing edge detection on the liquid surface position to identify a concave line of the liquid surface; The observation reading is determined based on the lowest point of the concave line of the liquid surface and the scale line of the burette.

3. The method for calibrating a burette reading according to claim 1, wherein: Calculating the relative position and shooting angle between the camera and the burette according to the liquid level change image, the camera parameters of the camera, and the instrument parameters of the burette includes: Identifying a burette image from the liquid level change image; wherein the burette image includes an image of all or part of the burette; Obtaining camera parameters of the camera; wherein the camera parameters include focal length, principal point coordinates and distortion coefficient; Obtaining instrument parameters of the burette; wherein the instrument parameters include the size and capacity of the burette; The coordinate parameters of the reference point on the burette image are determined according to the instrument parameters, and the relative position and shooting angle between the camera and the burette are calculated according to the coordinate parameters and the camera parameters.

4. The method for calibrating burette readings according to claim 3, wherein: Determining coordinate parameters of a reference point on the burette image according to the instrument parameters, and calculating a relative position and a shooting angle between the camera and the burette according to the coordinate parameters and the camera parameters, including: Selecting a plurality of reference points on the burette image; Determine the first coordinate of each reference point on the coordinate system according to the instrument parameters; The rotation matrix and translation vector of the camera are calculated according to the first coordinates and the camera parameters, and the relative position and shooting angle between the camera and the burette are determined according to the rotation matrix and the translation vector.

5. The method for calibrating burette readings according to claim 4, wherein: Correcting the observed reading according to the refractive index parameter of the burette wall and the relative position and shooting angle to obtain a calibration reading includes: Obtaining a second coordinate of the liquid level position on the coordinate system; Acquire a third coordinate of the camera on the coordinate system according to the relative position; Determine the refractive index parameter of the burette wall according to the material used for the burette; An optical path model is constructed according to the shooting angle, the second coordinate, the third coordinate and the refractive index parameter, and a calibration reading of the burette is obtained by performing tube wall refractive index compensation on the observed reading according to the optical path model.

6. The method for calibrating burette readings according to claim 1, wherein: Generating burette reading information based on the calibration reading and displaying the burette reading information at the liquid level position, including: Generate corresponding burette reading information from the calibration reading of each frame of liquid level change image; using tracking technology to identify the optical coding mark and determine the target display position of the burette reading information; The burette reading information is displayed according to the target display position.

7. The method for calibrating a burette reading according to any one of claims 1 to 6, wherein: Also includes: Obtaining corresponding solution parameters based on calibration readings identified in each frame of liquid level change image; Fitting a titration curve on a titration curve graph according to the calibration readings and their corresponding solution parameters; The titration curve is dynamically displayed on a display interface.

8. The method for calibrating a burette reading according to any one of claims 1 to 6, characterized in that: Also includes: Using a camera to capture a reading image of the potentiometric titrator in real time, and identifying a corresponding reading from the reading image; When the reading reaches the titration end point, a titration end point prompt is generated, and the reading image and the titration end point prompt are displayed in real time; or A camera is used to capture an image of the sample solution in the conical flask in real time, and the color of the sample solution is identified from the sample solution image. When a color change is detected in the sample solution to which the indicator is added, a titration end point prompt is generated and placed at the position of the conical flask for real-time display.

9. An experimental instrument for titration experiments, characterized in that: include: burette, conical flask, camera and terminal equipment; The burette is provided with an optical coding mark for titrating the solution; The conical flask is used to carry the sample solution; The camera is used to capture images in real time; The terminal device is configured to execute the steps of the burette reading calibration method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The storage medium stores at least one instruction, at least one program, code set or instruction set, and the at least one instruction, the at least one program, the code set or instruction set is loaded by the processor and executes the steps of the burette reading calibration method according to any one of claims 1 to 7.

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