Sediment space concentration measuring device based on visible light transmittance difference
By aligning a transparent water tank, camera, and searchlight in a dark, enclosed environment, and combining image processing and machine learning algorithms, the problems of light interference and unreasonable equipment placement in traditional methods were solved, enabling high-precision and rapid spatial distribution measurement of sediment concentration.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2026-03-13
AI Technical Summary
Traditional methods for measuring sand content are affected by external light and environmental factors, leading to inaccurate data. Improper equipment placement can cause light deflection or reflection, affecting image quality and measurement accuracy. Furthermore, most of these methods involve contact measurements, which can compromise test precision.
A device for measuring the spatial concentration of sediment based on the difference in visible light transmittance is designed. A closed space is formed by a light-shielding cloth and an iron frame. A transparent water tank, a camera, and a searchlight are aligned at the same horizontal height. The sediment concentration is measured using a non-contact optical method, and the spatial distribution of sediment concentration is inverted by combining image processing and machine learning algorithms.
It achieves reduced external interference in dark and enclosed environments, improves measurement accuracy and image quality, and uses a non-contact method to quickly obtain the spatial distribution of sediment concentration, avoiding the errors and interference of traditional methods, and is suitable for continuous monitoring.
Smart Images
Figure CN223992815U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a device for measuring the spatial concentration of sediment based on the difference in visible light transmittance, belonging to the field of water conservancy engineering. Background Technology
[0002] In the field of water conservancy engineering, especially in studies involving reservoir dredging and the initiation mechanism of river sediment particles, the determination of sediment concentration is a crucial task. Traditionally, sediment concentration measurement methods are mainly divided into two categories: contact and non-contact. Contact measurement methods include sampling and weighing methods and vibration methods. These methods obtain sediment concentration information by directly contacting water samples. Non-contact measurement methods include isotope methods, infrared radiation methods, and ultrasonic methods. These methods do not directly contact the water body but infer sediment concentration by detecting changes in light intensity or sound waves.
[0003] However, most traditional methods are not specifically designed to create a dark, enclosed, and interference-free measurement environment. Therefore, in practice, external light and other environmental factors can affect the measurement results, leading to inaccurate data. Furthermore, in some existing technologies, the placement of various devices is unreasonable, such as the improper positioning of the light source and camera, causing light to be deflected or reflected when passing through the sample, thus affecting image quality and measurement accuracy. Utility Model Content
[0004] This invention addresses the problem of measuring the spatial distribution of suspended sediment concentration. Its purpose is to enable experiments such as reservoir silt scouring and studies on the movement mechanism of sediment particles in pipelines to obtain the spatial distribution of sediment concentration more intuitively, accurately, and quickly. The technical solution of this invention is as follows:
[0005] A device for measuring the spatial concentration of sediment based on the difference in visible light transmittance includes an iron frame, a light-blocking cloth, a wooden table, a transparent water tank, a camera, and a searchlight. The iron frame is covered with the light-blocking cloth to form a closed space. The wooden table is placed in the middle of the closed space, the transparent water tank is placed directly above the wooden table, the searchlight is placed directly behind the transparent water tank, and the camera is placed directly in front of the transparent water tank.
[0006] Furthermore, the camera, searchlight, and transparent water tank are all at the same horizontal level.
[0007] Furthermore, an image processing window is formed on the side of the transparent water tank facing the camera, and the camera lens, the image processing window, and the searchlight are all positioned opposite each other at horizontal height.
[0008] Furthermore, the sediment spatial concentration measurement device also includes:
[0009] Multiple measuring cups are provided, each containing a measurement space for holding sediment samples. Each measuring cup has several measurement marks on its wall. The measuring cups are used to add sediment samples into the transparent water tank.
[0010] Furthermore, the sediment spatial concentration measurement device also includes:
[0011] A camera bracket, wherein the camera is fixed to the top of the camera bracket;
[0012] A light source bracket, wherein the searchlight is fixed to the top of the light source bracket;
[0013] The camera bracket and the light source bracket are located on opposite sides of the wooden table, and the heights of both the light source bracket and the camera bracket are adjustable.
[0014] This invention provides a device for measuring the spatial distribution of sand content, which has at least the following advantages compared to related technologies:
[0015] (1) Dark and enclosed experimental space: By using blackout cloth and iron frames to build a dark and enclosed space, the interference of external light and other environmental factors on the experimental results is effectively eliminated. This solves the problem of inaccurate data caused by external light in traditional methods.
[0016] (2) Optimize equipment layout to improve measurement accuracy: The transparent water tank is placed on a wooden table, while the camera and searchlight are located on opposite sides of the transparent water tank, and all three are aligned at the same horizontal level. This layout ensures that the light can penetrate the water sample vertically to reach the camera, reducing errors caused by angular deviations, while avoiding the impact of reflected or scattered light on image quality.
[0017] (3) Advantages of non-contact measurement: This device uses a non-contact optical method to measure sand content, avoiding the potential impact of traditional contact measurement methods (such as sampling and weighing methods, vibration methods, etc.) on the target being measured. This method not only improves the accuracy of measurement but also allows for faster data acquisition, making it particularly suitable for applications requiring continuous monitoring.
[0018] (4) Improve image quality and analysis accuracy: By carefully designing the location of the searchlight and the enclosed environment, it can be ensured that the captured transmission image has high contrast and clarity, which helps to analyze the R, G, B and gray values using image processing technology and machine learning algorithms, and then invert the spatial distribution of sand content.
[0019] Furthermore, this invention features non-contact and high efficiency. Currently, most sediment concentration measurements are achieved through contact methods, which inevitably affect experimental accuracy. This invention employs a non-contact optical method to measure sediment concentration, fundamentally avoiding interference with the measurement target. Moreover, existing sediment concentration measurement technologies are mostly single-point methods, making it difficult to obtain the spatial distribution of suspended sediment concentration. This invention, however, constructs a correlation between sediment-containing water bodies and pixel values based on image methods, enabling rapid and accurate acquisition of the spatial distribution of sediment concentration, offering unparalleled advantages over single-point measurement methods. Attached Figure Description
[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the structure of a sediment spatial concentration measurement device based on visible light transmittance difference, as provided in an embodiment of this utility model.
[0022] Figure 2 This is a flowchart illustrating a measurement method for a sediment spatial concentration measurement device based on visible light transmittance differences, according to a specific embodiment of this utility model.
[0023] Figure 3 This is a graph showing the relationship between the R, G, and B pixel values and grayscale values of an image and the sand content of a sample, as provided in this embodiment of the present invention.
[0024] Figure 4 This is a comparison chart of the actual and predicted values of sand content given in this embodiment of the utility model;
[0025] Figure 5 This is a diagram illustrating the parameter calibration process of the machine learning algorithm for the sediment content interpretation model, as given in this embodiment of the invention.
[0026] Figure 6 This is a spatial distribution diagram of sediment in a disturbance test provided for an embodiment of the present invention;
[0027] Figure 7 The spatial distribution inversion diagram of sand content is given for an embodiment of this utility model.
[0028] Explanation of reference numerals in the attached figures:
[0029] 1. Camera; 2. Wooden table; 3. Transparent water tank; 4. Sand-containing water sample; 5. Searchlight; 6. Iron frame; 7. Blackout cloth; 8. Image processing window. Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0031] In the description of the embodiments of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0032] In the description of the embodiments of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model based on the specific circumstances.
[0033] In this embodiment of the utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0034] The measuring device of this invention is used to measure the spatial concentration of sediment in a flume experiment. First, uniformly sediment-laden water samples with different concentrations are prepared according to a certain concentration gradient, and images of these samples at different concentrations are captured using camera 1. Then, OpenCV-Python is used to extract the R, G, and B pixel values and grayscale values of the images, constructing a sequence of average R, G, and B pixel values and grayscale values for the uniformly sediment-laden water images at different concentrations. Next, a machine learning algorithm is employed, using the sample sediment concentration as the label sequence and the sequence of average R, G, and B pixel values and grayscale values as the feature vector, to construct a water sediment concentration interpretation model. Finally, a disturbance experiment is conducted in a transparent flume 3, capturing images of the instantaneous sediment disturbance, and the aforementioned interpretation model is used to invert the spatial distribution of sediment concentration, thus realizing the application of the model.
[0035] like Figures 1 to 7 As shown in the accompanying drawings, the specific implementation scheme of a sediment spatial concentration measurement device based on visible light transmittance differences, according to this utility model, will be described in detail below. Figure 2 This is a schematic diagram illustrating the specific implementation steps of this method.
[0036] Step 1: Sample Preparation, including sample preparation and sampling of the test material. The test material used is sediment from the bottom of the Yellow River. First, the sediment is dried in a microwave oven, then ground into powder (to facilitate thorough mixing with water). A specific mass of sediment sample is taken using a measuring cup to establish a suitable sediment concentration gradient. Sampling process: Adjust the analytical balance, place an empty measuring cup, zero the balance, and add an appropriate amount of sediment powder. A total of 1 to 287 cups of samples are taken. To establish a suitable sediment concentration gradient, after preliminary experiments, it was determined that the sampling amount for the first 100 times is approximately 10g, for the 101st to 200th times approximately 20g, and for the 201st time and beyond approximately 30g. Each measuring cup is labeled as 1 to 287, and the weight of sand in each cup is m. i (i = 1, 2, ..., 286).
[0037] Step 2: Setting up the measuring device. For example... Figure 1 As shown, the measuring device of this invention includes an iron frame 6 covered with a light-blocking cloth 7, a transparent water tank 3 containing 3L of clean water, a camera 1, a searchlight 5, and a wooden table 2. The experiment is conducted in a dark, enclosed space. The iron frame 6 is completely covered with the light-blocking cloth 7 to form a dark, enclosed space. The wooden table 2 is placed in the center of the enclosed space, and the transparent water tank 3 containing 3L of clean water is placed directly above the wooden table 2. The searchlight 5 is placed directly behind the transparent water tank 3 to allow sufficient light to penetrate it. The camera 1 is placed directly in front of the transparent water tank 3, ensuring that the camera 1, the transparent water tank 3, and the searchlight 5 are at the same horizontal level for subsequent photographing and focusing. Except for the light source, everything in this experiment is covered with the light-blocking cloth 7 to prevent reflections from objects from affecting the experiment and to ensure uniform incident light.
[0038] Step 3: Photographic Experiment. Photographic experiments were conducted on transparent water tanks 3 with different sand contents. First, without adding any samples, the searchlight 5 was turned on, and the camera 1 was used to photograph the transparent water tank 3, obtaining a transmission image under clear water conditions. Sample number 1 was then poured into the transparent water tank 3, stirred thoroughly, and photographed again using the camera 1, obtaining a transmission image of turbid water. Subsequent samples were then processed in the same manner, resulting in a total of 287 transmission images. Throughout the different sets of photographs, the shutter speed, aperture, ISO, and light source conditions of the camera 1 were kept strictly consistent.
[0039] Step 4, Calculation of sample sand content. Based on the definition of liquid sand content, the sand content corresponding to each image is calculated using equation (1):
[0040]
[0041] In the formula, The sand content of the turbid water in the nth transparent water tank 3 is kg / m³. 3 V0 is the initial volume of clear water in the transparent water tank 3, in meters. 3 m i ρ is the mass of the dry sand sample taken from measuring cup i, in kg (i = 1, 2, ... 286); ρ is the density of the sand sample, in kg / m³. 3 .
[0042] Step 5: Pixel feature analysis of sediment-laden water body image. Based on the OpenCV-python interface program, code is written to extract the R, G, B pixel values and grayscale values of uniform sediment-laden water body image according to a specific image window. Among them, R, G, and B can be obtained by taking original images with a camera, and grayscale values are calculated by formula (2).
[0043] Gray=0.299R+0.587G+0.114B (2)
[0044] In the formula, Gray is the pixel gray value, and R, G, and B are the red light pixel value, green light pixel value, and blue light pixel value, respectively. The values of R, G, B, and Gray are all in the range of 0 to 255.
[0045] The calculated changes in R, G, B, and Gray values of water bodies with different sediment concentrations are as follows: Figure 3 As shown, with the increase of suspended sediment concentration, the light transmittance of the water body decreases, and the R, G, B and gray values of image pixels decrease accordingly. When the concentration is below 100 kg / m³, the light transmittance decreases. 3 The rate of decrease was very significant; and when the sand content reached 600 kg / m³ 3Subsequently, as the image's R, G, B, and grayscale pixel values tend to level off, there is no need to predict subsequent values. Therefore, the maximum predicted value of the inversion model built based on R, G, B, and grayscale values can reach 600 kg / m³. 3 Sand content, such as Figure 4 As shown.
[0046] Step 6: Construction of the Water Sediment Content Interpretation Model. The Support Vector Regression (SVR) algorithm is employed, using the sample sediment content as the label sequence and the average sequence of R, G, B pixel values and grayscale values of the image as the feature vector. 75% of the samples are divided into a training set and 25% into a test set. An SVR model is constructed based on the training set, and the model accuracy is evaluated based on the test set. R... 2 R is used as an evaluation metric to assess model accuracy. 2 The calculation formula is shown in equation (3).
[0047]
[0048] In the formula, R 2 The coefficient of determination for the predicted value; The predicted sediment content is 25%; y i The actual sand content is 25%. This represents the true average sand content of 25%.
[0049] For the SVR model, the choice of kernel function (rbf, poly, sigmoid, etc.) and the settings of parameters such as C (error term penalty factor) and gamma (kernel coefficient) significantly affect the model's accuracy. Therefore, a grid search method is used to obtain the optimal parameter combination scheme, and a sand content interpretation model is constructed based on this. In this experiment, it was found that the model fitting accuracy is higher when using the rbf kernel function. The effects of different error term penalty factors C on model accuracy are as follows: Figure 5 As shown. After training to obtain the optimal model, the model is tested using a test set. When C=100, the model accuracy R is [value missing]. 2 The value of 0.985 indicates that the model has high accuracy.
[0050] Step 7: Spatial Distribution Inversion of Sediment Content. After prolonged settling, the sediment in transparent tank 3 exhibits solid-liquid stratification, with sediment at the bottom and clear water at the top. A syringe filled with clear water is used to jet the sediment at the bottom. The disturbed sediment is dispersed within transparent tank 3. Images of the spatial distribution of the suspended sediment at the moment of impact disturbance are captured using a camera. (See attached image). Figure 6 During the acquisition of jet disturbance images, the environmental optical conditions must be kept strictly consistent with those of the previous sample calibration experiments to avoid affecting the optical image analysis of the images captured in the experiment.
[0051] Using OpenCV-python to perform pixel analysis on the captured images, the R, G, B, and grayscale values of each pixel can be obtained. These values serve as input to the interpretation model constructed in step 6. The interpretation model is then called pixel by pixel to invert the spatial distribution of sediment concentration, resulting in the spatial distribution of suspended sediment concentration at the instantaneous jet disturbance in the transparent water tank 3. Figure 7 As shown.
[0052] This invention provides a device for measuring the spatial distribution of sand content, which has at least the following advantages compared to related technologies:
[0053] (1) Dark and enclosed experimental space: By using the light-blocking cloth 7 and the iron frame 6 to build a dark and enclosed space, the interference of external light and other environmental factors on the experimental results is effectively eliminated. This solves the problem of inaccurate data caused by external light in traditional methods.
[0054] (2) Optimize equipment layout to improve measurement accuracy: The transparent water tank 3 is placed on the wooden table 2, while the camera 1 and the searchlight 5 are located on opposite sides of the transparent water tank 3, and the three are aligned at the same horizontal level. This layout ensures that the light can penetrate the water sample vertically to reach the camera, reducing errors caused by angular deviation, while avoiding the influence of reflected or scattered light on the image quality.
[0055] (3) Advantages of non-contact measurement: This device uses a non-contact optical method to measure sand content, avoiding the potential impact of traditional contact measurement methods (such as sampling and weighing methods, vibration methods, etc.) on the target being measured. This method not only improves the accuracy of measurement but also allows for faster data acquisition, making it particularly suitable for applications requiring continuous monitoring.
[0056] (4) Improve image quality and analysis accuracy: The carefully designed searchlight 5 position and enclosed environment can ensure that the captured transmission image has high contrast and clarity, which helps to analyze R, G, B and gray values using image processing technology and machine learning algorithms, and then invert the spatial distribution of sand content.
[0057] Furthermore, this invention features non-contact and high efficiency. Currently, most sediment concentration measurements are achieved through contact methods, which inevitably affect experimental accuracy. This invention employs a non-contact optical method to measure sediment concentration, fundamentally avoiding interference with the measurement target. Moreover, existing sediment concentration measurement technologies are mostly single-point methods, making it difficult to obtain the spatial distribution of suspended sediment concentration. This invention, however, constructs a correlation between sediment-containing water bodies and pixel values based on image methods, enabling rapid and accurate acquisition of the spatial distribution of sediment concentration, offering unparalleled advantages over single-point measurement methods.
[0058] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.
Claims
1. A device for measuring spatial concentration of sediment based on difference in visible light transmittance, characterized by, The device comprises an iron stand (6), a black cloth (7), a wooden table (2), a transparent water tank (3), a camera (1) and a searchlight (5), the black cloth (7) is covered on the outside of the iron stand (6) to define an enclosed space, the wooden table (2) is placed in the middle of the enclosed space, the transparent water tank (3) is placed right above the wooden table (2), the searchlight (5) is placed right behind the transparent water tank (3), and the camera (1) is placed right in front of the transparent water tank (3).
2. The device for measuring spatial concentration of sediment based on the difference of visible light transmittance according to claim 1, characterized in that, The horizontal height of the camera (1), the searchlight (5) and the transparent water tank (3) is consistent.
3. The device for measuring spatial concentration of sediment based on the difference of visible light transmittance according to claim 2, characterized in that, The side of the transparent water tank (3) facing the camera (1) is formed with an image processing window (8), the lens of the camera (1), the image processing window (8) and the searchlight (5) are all relatively arranged in the horizontal height.
4. The device for measuring spatial concentration of sediment based on difference in visible light transmittance according to any one of claims 1 to 3, characterized in that, Further comprising: a plurality of measuring cups, each of which is formed with a measuring space for containing a sample of the silt, and each of which is provided with a plurality of measuring marks on the cup wall, the measuring cup is used to put the sample of the silt into the transparent water tank (3).
5. The device for measuring spatial concentration of sediment based on difference in visible light transmittance according to any one of claims 1 to 3, characterized in that, Further comprising: a camera support, the camera (1) is fixed to the top end of the camera support; a light source support, the searchlight (5) is fixed to the top end of the light source support; the camera support and the light source support are respectively located on the opposite sides of the wooden table (2), and the height of the light source support and the height of the camera support are both adjustable.