阅读说明：本技术 一种可变倾角容器液位测量装置及方法 (Liquid level measuring device and method for container with variable inclination angle ) 是由 何宇 于 2021-07-08 设计创作，主要内容包括：本发明公开了一种可变倾角容器液位测量装置及方法,涉及自动测量技术领域,用于测量液体容器倾斜时容器内液面实时高度,包括标识盘,所述标识盘在液体容器倾斜时始终浮于液体表面,所述标识盘顶面设有若干圆斑且标识盘顶面与液面处于同一水平面,用于向图像采集模块提供参照；图像采集模块,所述图像采集模块位于液体容器顶部,用于采集标识盘图像信息来计算液位数据。本发明克服目前多数液位传感器只能测量垂直静态液面的缺陷,实现倾斜液位的动态测量,通过对漂浮于液面的标识盘进行定位及数据采集,有效抑制环境影响,计算出可变倾角容器内液体的液位,进而计算出液体容积,解决了姿态试验中,油箱液位测量的难题,实现余油量变化测量。(The invention discloses a device and a method for measuring the liquid level of a container with a variable inclination angle, which relate to the technical field of automatic measurement and are used for measuring the real-time height of the liquid level in the container when the liquid container is inclined, wherein the device comprises an identification disc, the identification disc always floats on the liquid surface when the liquid container is inclined, the top surface of the identification disc is provided with a plurality of circular spots, and the top surface of the identification disc and the liquid level are positioned on the same horizontal plane and are used for providing reference for an image acquisition module; and the image acquisition module is positioned at the top of the liquid container and used for acquiring the image information of the identification disc to calculate the liquid level data. The invention overcomes the defect that most liquid level sensors can only measure vertical static liquid level at present, realizes dynamic measurement of inclined liquid level, effectively inhibits environmental influence by positioning and data acquisition of the marking disc floating on the liquid level, calculates the liquid level of liquid in the container with variable inclination angle, further calculates the liquid volume, solves the problem of liquid level measurement of an oil tank in an attitude test, and realizes change measurement of residual oil quantity.)

1. A variable tilt angle container level measurement device for measuring the real time height of the liquid level in a liquid container (1) when the container is tilted, comprising:

the identification disc (2) is positioned in the liquid container (1) and always floats on the liquid surface when the liquid container (1) is inclined, a plurality of circular spots (201) are arranged on the top surface of the identification disc (2), and the top surface of the identification disc (2) and the liquid surface are in the same horizontal plane and used for providing reference for the image acquisition module (3);

the liquid level monitoring device comprises an image acquisition module (3), wherein the image acquisition module (3) is positioned at the top of the liquid container (1) and is used for acquiring image information of the identification disc (2) to calculate liquid level data.

2. A variable-inclination container level gauge according to claim 1, characterized in that the circular spots (201) on the top surface of the identification disc (2) are uniformly distributed and have the same size.

3. The device for measuring the liquid level of the container with the variable inclination angle according to claim 2, characterized in that the distances between the centers of the plurality of circular spots (201) and the center of the marking disc (2) are equal, and the included angles between the centers of any two adjacent circular spots (201) and the connecting line of the centers of the marking disc (2) are equal.

4. The variable-inclination container liquid level measuring device according to claim 2, wherein a plurality of ribs (202) with the same size are uniformly distributed at the bottom of the identification disc (2), and the density of the ribs (202) is greater than that of the identification disc (2).

5. A variable-inclination container level measuring device according to claim 2, characterized in that the area of the disc surface of the identification disc (2) is in direct proportion to the cross-sectional area of the liquid container (1).

6. A variable-inclination container level measuring device according to claim 1, characterized in that said image acquisition module (3) comprises a camera and an illumination device.

7. The device for measuring the liquid level of the container with the variable inclination angle according to claim 6, characterized in that an output end of the image acquisition module (3) is connected with an image signal receiver, and an output end of the image signal receiver is connected with an information processing module.

8. The variable tilt container level gauge apparatus of claim 7, wherein the information processing module comprises image processing software.

9. A method for measuring the liquid level of a container with a variable inclination angle is characterized by comprising the following steps:

s1: switching on a power supply, completing the installation of the image acquisition module (3), calibrating the marking disc (2), and entering a working state;

s2: initializing image processing software, and inputting calibration data to complete data setting of the image processing software;

s3: inputting an acquisition instruction to the image acquisition module (3), starting the lighting device, and acquiring a real-time image of the identification disc (2) by the camera;

s4: inputting image information acquired by a camera into image processing software, extracting characteristic parameters of the identification disc (2), and calculating to obtain the real-time liquid level in the liquid container (1) through the image processing software;

s5: and acquiring the inclination angle of the liquid container (1) and the size characteristic data of the liquid container (1), and calculating to obtain the volume of the liquid in the liquid container (1).

Technical Field

The invention belongs to the technical field of automatic measurement, and particularly relates to a device and a method for measuring liquid level of a container with a variable inclination angle.

Background

During the posture simulation test of the lubricating oil system, the lubricating oil cavity, the oil tank and other parts need to measure the liquid level height to determine the oil accumulation capacity, so that the matching research of the posture and the lubricating oil system can be realized. On one hand, in the continuous change process of the inclination angle, how to obtain the change of the corresponding liquid level is important for the analysis of the test and the design improvement of key parts; on the other hand, the lubricating oil may overflow and leak under a large inclination angle, and the safety of test equipment and personnel is threatened. Currently, there is no level sensor that can measure the level of an inclined liquid. Therefore, the liquid level measurement can only depend on reading the pre-calibrated scale manually, which wastes time and labor, and has low accuracy and tedious test preparation work.

The camera cooperates with the vision processing algorithm, and the wide application is in fields such as range finding, formation of image, and non-contact measurement, response speed is fast, and the precision is high, can be used to slope container level measurement in theory, actually has the technical difficulty: the test is a dynamic process, the liquid level may fluctuate violently, and oil mist may exist between the camera and the liquid level, so that the liquid level identification and calibration are difficult. In the prior art, no examples and related articles are found for camera signal processing for variable tilt level measurement.

Therefore, the present invention provides a device and a method for measuring a liquid level of a container with a variable inclination angle, so as to solve the problems in the background art.

Disclosure of Invention

The invention aims to provide a device and a method for measuring the liquid level of a container with a variable inclination angle, which aim to solve the problems that the liquid level sensors in the prior art proposed in the background art require vertical measurement and cannot be obliquely installed and used.

According to one aspect of the invention, the invention provides a liquid level measuring device for a container with a variable inclination angle, which is used for measuring the real-time height of the liquid level in the container when the liquid container is inclined, and comprises an identification disc, wherein the identification disc is positioned in the liquid container and always floats on the liquid surface when the liquid container is inclined, the top surface of the identification disc is provided with a plurality of circular spots, and the top surface of the identification disc and the liquid level are positioned at the same horizontal plane and used for providing reference for an image acquisition module; and the image acquisition module is positioned at the top of the liquid container and used for acquiring the image information of the identification disc to calculate the liquid level data.

According to an exemplary embodiment of the present invention, the circular spots on the top surface of the identification disc are uniformly distributed and have the same size.

According to another exemplary embodiment of the invention, the centers of the plurality of circular spots are equidistant from the center of the marking disc, and the included angles between the centers of any two adjacent circular spots and the connecting line of the centers of the marking discs are equal.

According to another exemplary embodiment of the present invention, a plurality of rib plates with the same size are uniformly distributed on the bottom of the logo disc, and the density of the rib plates is greater than that of the logo disc.

According to another exemplary embodiment of the present invention, the area of the face of the identification disc is directly proportional to the cross-sectional area of the liquid container.

According to another exemplary embodiment of the present invention, the image acquisition module comprises a camera and an illumination device.

According to another exemplary embodiment of the present invention, an output end of the image acquisition module is connected to an image signal receiver, and an output end of the image signal receiver is connected to the information processing module.

According to another exemplary embodiment of the present invention, the information processing module comprises image processing software.

According to another aspect of the present invention, there is provided a variable-inclination container liquid level measuring method, comprising the steps of:

s1: switching on a power supply, completing the installation of the image acquisition module, calibrating the identification disc, and entering a working state;

s2: initializing image processing software, and inputting calibration data to complete data setting of the image processing software;

s3: inputting an acquisition instruction to an image acquisition module, starting an illuminating device, and acquiring a real-time image of the identification disc by a camera;

s4: inputting image information acquired by a camera into image processing software, extracting characteristic parameters of the identification disc, and calculating by the image processing software to obtain the real-time liquid level in the liquid container;

s5: and acquiring the inclination angle of the liquid container and the size characteristic data of the liquid container, and calculating to obtain the volume of the liquid in the liquid container.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the liquid level measuring device and method for the variable-inclination-angle container, provided by the invention, the marking disc floating on the liquid level is positioned and data are acquired, so that the environmental influence is effectively inhibited, the liquid level of liquid in the variable-inclination-angle container is calculated, the liquid volume is further calculated, the problem of measuring the liquid level of an oil tank in an attitude test is solved, and the variable measurement of the residual oil quantity is facilitated.

2. The invention overcomes the defect that most liquid level sensors can only measure vertical static liquid level at present, can realize dynamic measurement of inclined liquid level and has strong environmental adaptability.

Drawings

In order to facilitate understanding for those skilled in the art, the present invention will be further described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of the overall structure of a liquid level measuring device for a container with a variable inclination angle;

FIG. 2 is a cross-sectional view of a variable tilt angle container level measurement apparatus;

FIG. 3 is a schematic view of the overall structure of the logo plate;

FIG. 4 is a schematic perspective view;

FIG. 5 is a first embodiment of a liquid volume within a liquid container;

fig. 6 shows a second embodiment of the liquid volume in the liquid container.

In the figure: 1. a liquid container; 2. a logo plate; 201. round spots; 202. a rib plate; 3. and an image acquisition module.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention are further described in detail below by way of examples with reference to the accompanying drawings. In the specification, the same or similar reference numerals denote the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the general inventive concept of the present invention and should not be construed as limiting the invention.

Furthermore, in the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown in schematic form in order to simplify the drawing.

According to a general technical concept of the present invention, as shown in fig. 1-6, a variable-inclination-angle liquid level measuring device for a container is provided, which is used for measuring the real-time height of the liquid level in the container when a liquid container 1 is inclined, and comprises an identification disc 2, wherein the identification disc 2 is positioned in the liquid container 1 and always floats on the liquid surface when the liquid container 1 is inclined, the top surface of the identification disc 2 is provided with a plurality of circular spots 201, the top surface of the identification disc 2 and the liquid level are in the same horizontal plane for providing reference for an image acquisition module 3, and the color of the top surface of the identification disc 2 and the color of the plurality of circular spots 201 are strong contrast colors, so that image processing software can extract characteristic parameters of the identification disc 2; the image acquisition module 3 is positioned at the top of the liquid container 1, comprises a camera and an illuminating device and is used for acquiring image information of the identification disc 2 to calculate liquid level data; the output end of the image acquisition module 3 is connected with an image signal receiver, the output end of the image signal receiver is connected with an information processing module, and the information processing module comprises image processing software.

As shown in fig. 4, firstly, referring to the optical line-of-sight distance measurement principle, the distance between the circular spot 201 on the surface of the marker disc 2 and the camera is determined, the marker disc 2 is vertically placed right in front of the camera lens, and the corresponding relation between each size on the marker disc 2 and the distance of the marker disc 2 is recorded through image analysis and is used as the basis for subsequently judging the distance.

According to the formula:

wherein D is the distance from a certain point to the lens of the camera, A is the visual angle of the camera, and L is the width of the point in the image.

The spot 201 on the surface of the marking disc 2 is spaced from the camera by a distance equal to the product of the cotangent of one half of the viewing angle and one half of the width of the spot.

After the adjustment to the optimal state, the visual angle of the camera is fixed, so that the linear relation between the distance and the width can be approximately considered.

D＝kL

Where k is a coefficient (constant).

As shown in fig. 3, in the illustrated embodiment, a plurality of circular spots 201 with the same size are uniformly distributed on the top surface of the marking disc 2, the number and the shape of the reference pixels are compared with the previously calibrated distance, the relative distance between the four circular spots 201 and the camera can be determined, the camera acquires an image of the marking disc 2 at a certain moment, and when the marking disc 2 inclines along with the liquid level, the circular spots 201 are represented as an ellipse in the image, based on the shortest side of the ellipse.

Preferably, in this embodiment, the distances between the centers of the plurality of circular spots 201 and the center of the label disc 2 are equal, and the included angles between the centers of any two adjacent circular spots 201 and the connecting line between the centers of the label disc 2 are equal.

Preferably, in this embodiment, a plurality of rib plates 202 with the same size are uniformly distributed at the bottom of the logo disc 2, and the density of the rib plates 202 is greater than that of the logo disc 2.

Preferably, in the present embodiment, the area of the plate surface of the identification plate 2 is in direct proportion to the cross-sectional area of the liquid container 1.

A method for measuring the liquid level of a container with a variable inclination angle comprises the following steps:

s1: switching on a power supply, completing the installation of the image acquisition module 3, calibrating the marking disc 2, and entering a working state;

s2: initializing image processing software, and inputting calibration data to complete data setting of the image processing software;

s3: inputting an acquisition instruction to the image acquisition module 3, starting the lighting device, and acquiring a real-time image of the identification disc 2 by the camera;

s4: inputting image information acquired by a camera into image processing software, extracting characteristic parameters of the identification disc 2, and calculating by the image processing software to obtain the real-time liquid level in the liquid container 1;

s5: the inclination angle of the liquid container 1 and the dimensional characteristic data of the liquid container 1 are acquired, and the volume of the liquid in the liquid container 1 is calculated and obtained.

The following describes the image processing method in detail:

the method comprises the following steps: image filtering, namely, in order to obtain a clearer image of the identification disc 2 and eliminate noise influence, a median filtering method is adopted for image processing, namely, pixel points in a certain range are sorted according to the gray scale, and the median value is taken as the gray scale value, so that the method can protect image details to the maximum extent and remove noise; the marking disc 2 is of strong contrast color and is obvious in a container with a limited volume, and even if a small amount of oil mist is generated in an oil tank, a high identification degree can be obtained through filtering.

Step two: edge extraction, namely, realizing image edge detection by adopting a Canny algorithm according to the difference of image gray level, color and texture, and if more than two points with 0 gray level exist in the neighborhood of one point with 0 gray level, the point is not an edge point; if more than two points with the gray scale not being 0 exist in the neighborhood of one point with the gray scale being 0, the point is an edge point; after all points of the image are screened, a single-pixel edge profile is finally obtained.

Step three: and identifying the size, determining the size of the circular spot 201 on the surface of the marking disc 2 in the image according to the coordinates of each edge pixel point in the image, and comparing the linear relation between the previously calibrated distance and the width to obtain the actual distance from the circular spot 201 to the camera lens.

After the distances between the four circular spots 201 and the distances between the circular spots 201 and the camera are obtained, the relative distance between the camera and the plane (namely the liquid level) where the marking disc 2 is located is calculated according to a three-dimensional space four-point positioning method. The specific method comprises the following steps: the center of the plane of the marking disc 2 is taken as the origin, the disc surface is taken as the XY plane, and the coordinates of the four circular spots 201 are respectively (x)₁，y₁，z₁)、(x₂，y₂，z₂)、(x₃，y₃，z₃)、(x₄，y₄，z₄) And the coordinates of the lens position of the camera are (x, y, z), which can be represented by the following formula:

subtracting:

conversion to matrix multiplication:

by calculating the inverse matrix of the left matrix, the position coordinates of the camera lens can be obtained, and finally the distance between the camera and the liquid level can be calculated.

Next, by obtaining the inclination angle and the dimensional volume of the liquid container 1, the liquid level data is matched, and the liquid volume and the relative position of the liquid surface in the liquid container 1 can also be obtained.

As shown in fig. 5 and 6, the liquid container 1 is a regular box or a cylinder in two different embodiments of the liquid volume in the liquid container 1.

In fig. 5 and 6: h is the liquid level height (vertical distance of the camera from the liquid level), C is the inclination angle of the container, E is the length of the bottom surface of the container, F is the width of the bottom surface of the container, G is the height of the container, and the volume of the container is the product of the bottom area S (a calculation formula is determined according to the shape of the liquid container) and the height G.

As shown in fig. 5, in a first embodiment of the liquid volume in the liquid container 1:

when the highest point and the lowest point of the liquid level are respectively positioned on the inner walls of the two liquid containers 1 which are parallel to each other, the liquid volume in the liquid container 1 is half of the column volume between the highest point and the lowest point of the liquid level plus the column volume below the lowest point of the liquid level.

The liquid volume in the liquid container 1 at this time is:

as shown in fig. 6, in a second embodiment of the liquid volume in the liquid container 1:

when the highest point and the lowest point of the liquid level are respectively positioned on the inner walls of the two containers which are vertical to each other, the liquid volume in the liquid container 1 is half of the volume of the residual column between the highest point and the lowest point of the liquid.

The liquid volume in the liquid container 1 at this time is:

the above embodiments are provided to further explain the objects, technical solutions and advantages of the present invention in detail, it should be understood that the above embodiments are only examples of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.