Bubble measurement method and system

Abstract

The invention provides a bubble measurement method. The method comprises the following steps: controlling a bubble generation device to generate a preset number of bubbles; acquiring continuous multi-frame images, which are acquired by a camera device and about the rising motion of the bubbles in the water body within a preset time period; determining the rising displacement and instantaneous speed of the bubbles in each frame of image in the water body by utilizing the positions of the bubbles of the multiple frames of images and the time interval between every two adjacent frames of images; smoothing the instantaneous speeds corresponding to the multiple frames of images to obtain the average speed of the bubbles in the preset time period; based on the average speed of the bubbles, the preset time period and the total displacement amount of the bubbles in the preset time period, the microscopic deformation amount of the bubbles is determined; and obtaining a measurement result of the bubbles based on the average speed and the microscopic deformation quantity of the bubbles in the preset time period. The invention provides a system for bubble measurement.

Description

Technical Field

[0001] The present disclosure relates to the technical fields of fluid mechanics and image processing, and in particular to a method and system for bubble measurement. Background Art

[0002] Bubble motion behavior has important research value in the fields of fluid mechanics, chemical engineering, environmental engineering, etc. The bubble velocity information and bubble deformation information can help researchers understand the flow field characteristics, interfacial mass transfer process and gas-liquid interaction inside the fluid. In wastewater treatment, chemical mass transfer and bubble-induced turbulence research, accurate measurement of bubble motion is particularly important. For example, based on the bubble velocity measurement results, it can help understand the energy consumption and utility of large bubble aeration, and support the energy saving and carbon reduction of large aeration equipment such as membrane bioreactors. Bubble deformation information can provide rich information for bubble dynamics research.

[0003] However, bubbles will deform and flip during their movement, which will significantly affect the accurate measurement of their speed and path. How to effectively measure the bubble deformation and speed of bubbles rising in water is a difficulty in current bubble motion research. Summary of the invention

[0004] In view of this, the present disclosure provides a method and system for bubble measurement.

[0005] The method for bubble measurement provided by the present disclosure includes: controlling a bubble generating device to generate a predetermined number of bubbles; obtaining a continuous multi-frame image of bubbles rising in a water body within a preset time period collected by a camera device; determining the displacement and instantaneous speed of the bubbles in each frame image rising in the water body by using the positions of the bubbles in each of the multi-frame images and the time interval between each two adjacent frames of images; smoothing the instantaneous speeds corresponding to each of the multi-frame images to obtain an average speed of the bubbles within a preset time period; determining the microscopic deformation of the bubbles based on the average speed of the bubbles, the preset time period and the total displacement of the bubbles within the preset time period, wherein the total displacement is obtained by accumulating the displacement of the bubbles in each frame image rising in the water body; and obtaining the measurement result of the bubbles based on the average speed and microscopic deformation of the bubbles within the preset time period.

[0006] According to an embodiment of the present disclosure, the displacement and instantaneous speed of the bubbles rising in the water body in each frame are determined by utilizing the positions of the bubbles in each of the multiple frame images and the time interval between each two adjacent frames, including: based on the bubble boundary, bubble matching is performed on two adjacent frames to determine the positions of the matching bubbles in the two adjacent frames; based on the positions of the matching bubbles in the two adjacent frames and the time interval between the two adjacent frames, the displacement and instantaneous speed of the bubbles rising in the water body in each frame is determined.

[0007] According to an embodiment of the present disclosure, a grid calibration coordinate system is included in multiple frames of images; based on the positions of matched bubbles in two adjacent frames and the time interval between the two adjacent frames, the displacement and instantaneous speed of the bubbles rising in the water body in each frame are determined, including: using the grid calibration coordinate system to calibrate the positions of matched bubbles in two adjacent frames to obtain the grid positions of the bubbles in the two adjacent frames for the grid calibration coordinate system, wherein the positions of the bubbles in the two adjacent frames represent the pixel positions in the pixel coordinate system; based on the grid positions of the bubbles in the two adjacent frames for the grid calibration coordinate system, the displacement of the bubbles between the two adjacent frames is determined; and according to the displacement and the time interval between the two adjacent frames, the instantaneous speed of the bubbles is determined.

[0008] According to an embodiment of the present disclosure, bubble matching is performed on two adjacent frames of images to determine the positions of matching bubbles in the two adjacent frames of images, including: determining a target area of ​​the bubble from a previous frame of image, wherein the target area includes a bubble boundary of the bubble in the previous frame of image; determining an associated target area matching the target area in a subsequent frame of image based on bubble pixels in the target area of ​​the bubble in the previous frame of image; and determining the positions of matching bubbles in the two adjacent frames of images based on the target area and the associated target area.

[0009] According to an embodiment of the present disclosure, based on bubble pixels of a target area of ​​a bubble in a previous frame image, an associated target area matching the target area is determined in a subsequent frame image, including: dividing the target area of ​​the previous frame image into multiple target sub-areas, the target sub-areas including at least a portion of the bubble boundary; determining a correlation coefficient between the target sub-area and each of the multiple candidate sub-areas based on bubble pixels of the target sub-area of ​​each previous frame image and bubble pixels of each of the multiple candidate sub-areas of the subsequent frame image; determining an associated target sub-area with the maximum correlation with the target sub-area of ​​the previous frame image in the subsequent frame image using the multiple correlation coefficients; and obtaining an associated target area based on the multiple associated target sub-areas with the maximum correlation.

[0010] According to an embodiment of the present disclosure, the total displacement of the bubble includes the total displacement of each of the multiple target sub-regions; based on the average speed of the bubble, a preset time period and the total displacement of the bubble in multiple consecutive frames of images, the microscopic deformation of the bubble is determined, including: determining the total displacement of the bubble in the first frame image without deformation based on the average speed and the preset time period; determining the microscopic deformation of the bubble based on the total displacement of each of the multiple target sub-regions of the bubble and the total displacement of the bubble in the first frame image without deformation.

[0011] Another aspect of the present disclosure provides a system for bubble measurement, comprising: an electronic device for executing the steps of the above method; a bubble generating device suitable for generating bubbles and accommodating the movement of the bubbles; and a camera device suitable for capturing images of the bubble movement and sending the images to the electronic device.

[0012] According to an embodiment of the present disclosure, the bubble generating device includes: a transparent container, a sealed cavity is formed in the transparent container, the sealed cavity is suitable for receiving external water and using the gap outside the water to form the bubble; a calibration panel, the calibration panel is drawn with a grid calibration coordinate system, is arranged on the outer wall of the transparent container and makes the grid calibration coordinate system face the camera device.

[0013] According to an embodiment of the present disclosure, a background light source is further provided on a side of the calibration panel facing the transparent container.

[0014] According to an embodiment of the present disclosure, the bubble generating device mechanism also includes: a fixed frame, which is rotatably connected to the transparent container and is suitable for rotating the transparent container to make the bubble move in the opposite direction when the bubble moves to a preset position, so as to repeatedly capture images of the movement of the bubble.

[0015] According to the embodiments of the present disclosure, by controlling the bubble generating device to generate a predetermined number of bubbles, and combining the continuous multi-frame images collected by the camera device, using the position information of the bubbles in the image and the time interval between two adjacent frames of images, the instantaneous velocity of the bubbles can be calculated more accurately, and then the average velocity (i.e., the Reynolds average velocity) that can reflect the movement state of the bubbles in the fluid is obtained through smoothing processing, thereby reducing the error caused by instantaneous velocity fluctuations, effectively solving the problem of bubble deformation interference during bubble velocity measurement, and improving the accuracy and reliability of the data. By combining the average velocity of the bubbles, the preset time period, and the total displacement, the microscopic deformation of the bubbles can be quantified, which helps to understand the slight changes in the shape or volume of the bubbles caused by various factors during the rising process, and provides rich information for the study of bubble dynamics. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0017] Figure 1 A flow chart of a method for bubble measurement according to an embodiment of the present disclosure is schematically shown;

[0018] Figure 2 Schematically shows a flow chart of measuring the average velocity of bubbles according to an embodiment of the present disclosure;

[0019] Figure 3aSchematically shows the position of bubbles in two adjacent frames of images and the corresponding instantaneous speed visualization image effect diagram according to an embodiment of the present disclosure;

[0020] Figure 3b A diagram schematically shows the position of another bubble in two adjacent frames of images and the corresponding instantaneous speed visualization image according to an embodiment of the present disclosure;

[0021] Figure 4 A schematic diagram schematically illustrates a bubble measurement system according to an embodiment of the present disclosure; and

[0022] Figure 5 The figure schematically shows a transparent container rotating according to an embodiment of the present disclosure.

[0023] Reference numerals

[0024] 1. Bubble generating device;

[0025] 11. Transparent container;

[0026] 12. Calibration panel;

[0027] 13. Fixed bracket

[0028] 2. Camera device. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0030] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0031] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0032] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0033] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0034] Figure 1 The flowchart of the bubble measurement method according to the embodiment of the present disclosure is schematically shown.

[0035] like Figure 1 As shown, the method includes: operations S110 to S150.

[0036] In operation S110, the bubble generating device is controlled to generate a predetermined number of bubbles.

[0037] In operation S120, a plurality of continuous frames of images collected by a camera device and showing the bubbles moving upward in a water body within a preset time period are acquired.

[0038] In operation S130, the displacement and instantaneous speed of the bubble in each frame of image rising in the water body are determined by using the positions of the bubbles in each of the multiple frames of image and the time interval between two adjacent frames of image.

[0039] In operation S140, a smoothing process is performed on the instantaneous speeds corresponding to the plurality of frames of images to obtain an average speed of the bubble within a preset time period.

[0040] In operation S150, the microscopic deformation amount of the bubble is determined based on the average speed of the bubble, the preset time period and the total displacement of the bubble within the preset time period, where the total displacement is accumulated according to the displacement of the bubble rising in the water body in each frame image.

[0041] In operation S160, a measurement result of the bubble is obtained based on an average velocity and a microscopic deformation amount of the bubble within a preset time period.

[0042] In some embodiments, the predetermined number of bubbles may be one bubble.

[0043] In some embodiments, the preset time period may be 1 second, 2 seconds, 3 seconds, 5 seconds, 10 seconds, etc. A video of bubbles rising in water may be captured using a camera, and a video editing tool may be used to extract multiple consecutive frames of images from the video, and the time interval between adjacent frames of images may be recorded. For example, for a 960 fps video, the time interval between adjacent frames of images is 1 / 960 seconds.

[0044] In some embodiments, after obtaining the continuous multi-frame images, the multi-frame images can be preprocessed. Preprocessing can include adjusting the brightness and contrast of the multi-frame images to ensure uniform brightness of the images and enhance the contrast between the bubbles and the background. Preprocessing can also include grayscale processing of the multi-frame images to convert the multi-frame images into grayscale images to avoid interference from color noise. Preprocessing can also include correcting the distortion of the multi-frame images to ensure that the images do not produce geometric distortion and the size ratio of the corrected images remains unchanged to ensure the accuracy of displacement measurement.

[0045] In some embodiments, after preprocessing multiple frames of images, the bubbles in the images can be identified using image processing technology, and the positions of the bubbles in each of the multiple frames of images can be determined. The displacement of the bubbles in each frame of image rising in the water body can be determined based on the positions of the bubbles in each of the two adjacent frames of image. The instantaneous speed of the bubbles rising in the water body can be determined based on the displacement of the bubbles in each frame of image rising in the water body and the time interval between each of the two adjacent frames of image.

[0046] In some embodiments, due to the influence of various factors such as image noise, changes in bubble shape, water flow disturbance, etc., the calculated instantaneous velocity may have certain fluctuations and errors. By smoothing the instantaneous velocity, the fluctuations and errors in the instantaneous velocity can be reduced, thereby more accurately describing the motion characteristics of the bubble. The formula for smoothing the instantaneous velocity to obtain the average velocity of the bubble within a preset time period is as follows:

[0047] (1)

[0048] in: is the average speed; T is the preset time period;

[0049] In some embodiments, ideally, if the bubble does not deform during the ascent, the total displacement of the bubble can be determined by the average speed and the preset time period. However, in actual situations, the bubble may be affected by various factors and undergo slight deformation, resulting in a deviation between the actual ascent path or speed of the bubble and the theoretical value. Therefore, by comparing the actual total displacement of the bubble with the theoretical total displacement (i.e., the average speed multiplied by the preset time period), the microscopic deformation of the bubble can be determined. If the actual total displacement is greater than or less than the theoretical total displacement, it may mean that the bubble has undergone deformation such as expansion or contraction during the ascent.

[0050] According to the embodiments of the present disclosure, by controlling the bubble generating device to generate a predetermined number of bubbles, and combining the continuous multi-frame images collected by the camera device, using the position information of the bubbles in the image and the time interval between two adjacent frames of images, the instantaneous velocity of the bubbles can be calculated more accurately, and then the average velocity (i.e., the Reynolds average velocity) that can reflect the movement state of the bubbles in the fluid is obtained through smoothing processing, thereby reducing the error caused by instantaneous velocity fluctuations, effectively solving the problem of bubble deformation interference during bubble velocity measurement, and improving the accuracy and reliability of the data. By combining the average velocity of the bubbles, the preset time period, and the total displacement, the microscopic deformation of the bubbles can be quantified, which helps to understand the slight changes in the shape or volume of the bubbles caused by various factors during the rising process, and provides rich information for the study of bubble dynamics.

[0051] According to an embodiment of the present disclosure, determining the displacement and instantaneous speed of the bubbles in each frame of image rising in the water body by using the positions of the bubbles in each of the multiple frames of image and the time interval between each two adjacent frames of image may include: performing bubble matching on two adjacent frames of image based on the bubble boundary to determine the positions of the matching bubbles in the two adjacent frames of image; determining the displacement and instantaneous speed of the bubbles in each frame of image rising in the water body based on the positions of the matching bubbles in the two adjacent frames of image and the time interval between the two adjacent frames of image.

[0052] In some embodiments, the bubble boundary can be processed for each frame of the image through a pre-trained boundary recognition model to obtain the recognition result of the bubble boundary, thereby achieving accurate segmentation of the bubble boundary.

[0053] In some embodiments, two adjacent frames of images may be matched by using an image displacement matching technique. After determining that the bubble is successfully matched in the two adjacent frames of images, the pixel positions of the matched bubbles in the two adjacent frames of images may be determined, thereby determining the positions of the matched bubbles in the two adjacent frames of images.

[0054] Based on the positions of the matched bubbles in two adjacent frames of images, the pixel displacement of the bubbles in the two adjacent frames of images can be determined. Based on the pixel displacement and time interval of the bubbles in the two adjacent frames of images, the instantaneous velocity of the bubbles can be determined.

[0055] According to an embodiment of the present disclosure, a grid calibration coordinate system is included in the multiple frames of images; based on the positions of the matched bubbles in the two adjacent frames of images and the time interval between the two adjacent frames of images, determining the displacement and instantaneous speed of the bubbles in each frame of image rising in the water body may include: using the grid calibration coordinate system to calibrate the positions of the matched bubbles in the two adjacent frames of images, and obtaining the grid positions of the bubbles in the two adjacent frames of images for the grid calibration coordinate system. The positions of the bubbles in the two adjacent frames of images represent the pixel positions in the pixel coordinate system; based on the grid positions of the bubbles in the two adjacent frames of images for the grid calibration coordinate system, determining the displacement of the bubbles between the two adjacent frames of images; and determining the instantaneous speed of the bubbles according to the displacement and time interval between the two adjacent frames of images.

[0056] In some embodiments, the grid calibration coordinate system can be used to transform the pixel positions of the bubble in the pixel coordinate system representing the positions of the bubbles in two adjacent frames into grid positions in the grid calibration coordinate system, thereby determining the actual displacement of the bubble between the two adjacent frames.

[0057] The instantaneous velocity of the bubble is obtained by dividing the displacement of the bubble between two adjacent frames of images by the time interval between the two frames of images.

[0058] (2)

[0059] (3)

[0060] in: and are the displacement distances of the bubble between the two frames of images along the x-axis (i.e., horizontal direction) and the y-axis (i.e., vertical direction); is the time interval between two frames, and are the component velocities of the bubble along the x-axis and y-axis in the two frames of images respectively.

[0061] The instantaneous velocities of the bubble in the x-axis and y-axis directions are synthesized to obtain the synthesized instantaneous velocity of the bubble.

[0062] According to an embodiment of the present disclosure, the grid calibration coordinate system provides a standardized benchmark for the measurement of bubble positions. Through the grid calibration coordinate system, the pixel positions of bubbles in two adjacent frames of images can be converted into grid positions, making the calibration of bubble positions more accurate and reliable.

[0063] According to an embodiment of the present disclosure, bubble matching is performed on two adjacent frames of images, and determining the positions of matching bubbles in the two adjacent frames of images may include: determining a target area of ​​the bubble from the previous frame of image, the target area including the bubble boundary of the bubble in the previous frame of image; determining an associated target area matching the target area in the next frame of image based on bubble pixels in the target area of ​​the bubble in the previous frame of image; and determining the positions of matching bubbles in the two adjacent frames of images based on the target area and the associated target area.

[0064] In some embodiments, when bubble matching is performed on two adjacent frames of images, bubbles in the previous frame of image may be identified first, and the bubble boundaries thereof may be determined, and the target area may be determined according to the bubble boundaries.

[0065] In some embodiments, pixel features, such as grayscale values, in the bubble target region in the previous frame image are used to match the candidate region in the next frame image to obtain an associated target region that matches the target region.

[0066] In some embodiments, the center position of the bubble in two adjacent frames can be determined based on the target area and the associated target area, and the displacement of the bubble in the two adjacent frames can be determined based on the distance between the center positions of the bubble in the two adjacent frames. The present disclosure is not limited to this, and the displacement of the bubble in the two adjacent frames can also be determined based on the position of the corners in the target area and the associated target area or the position of the bubble boundary area that has not been deformed in the target area and the associated target area. Then, the instantaneous speed of the bubble is determined in combination with the time interval between the two adjacent frames.

[0067] According to an embodiment of the present disclosure, by determining a target area of ​​a bubble in a previous frame image and determining an associated target area in a subsequent frame image, the area that needs to be matched can be reduced, thereby reducing the amount of calculation.

[0068] Figure 2 The flowchart of measuring the average velocity of bubbles according to an embodiment of the present disclosure is schematically shown.

[0069] like Figure 2As shown, from the multiple-frame image 210, two adjacent frame images 220 are acquired in sequence, and based on the bubble pixels of the target area 230 of the bubble in the previous frame image, the associated target area 240 of the bubble in the next frame image that matches the target area is determined in the next frame image; according to the respective positions of the target area 230 of the bubble in the previous frame image and the associated target area 240 of the bubble in the next frame image, the displacement 250 of the bubble is determined, and according to the displacement 250 of the bubble and the time interval 260 between the two adjacent frame images 220, the instantaneous speed 270 of the bubble is determined, and the instantaneous speed of the bubble in each frame image is smoothed to obtain the average speed 280 of the bubble.

[0070] According to an embodiment of the present disclosure, determining an associated target area that matches the target area in a subsequent frame image based on bubble pixels of a target area of ​​a bubble in a previous frame image may include: dividing the target area of ​​the previous frame image into multiple target sub-areas, the target sub-areas including at least a portion of the bubble boundary; determining a correlation coefficient between the target sub-area and each of the multiple candidate sub-areas based on the bubble pixels of the target sub-area of ​​each previous frame image and the bubble pixels of each of the multiple candidate sub-areas of the subsequent frame image; determining an associated target sub-area with the maximum correlation with the target sub-area of ​​the previous frame image in the subsequent frame image using the multiple correlation coefficients; and obtaining an associated target area based on the multiple associated target sub-areas with the maximum correlation.

[0071] In some embodiments, the target area of ​​the previous frame image can be divided into multiple target sub-areas, for example, it can be a target sub-area of ​​15x15 pixels, which is only for illustration, and can also be a target sub-area of ​​other sizes. Each target sub-area can be tracked separately and matched with multiple candidate sub-areas of the next frame image, and the correlation coefficients of the target sub-area and the multiple candidate sub-areas are calculated. The calculation formula of the correlation coefficient is as follows:

[0072] (4)

[0073] in, and Respectively represent the grayscale values ​​of the pixels of the target sub-region and the candidate target sub-region in two adjacent frames of images, and m and n are the displacements of the two adjacent frames of images in the X-axis and Y-axis respectively; and Represent the average grayscale value of the two image pixels respectively; It means to sum the gray values ​​of all pixels in the image.

[0074] The value range of the correlation coefficient is usually between [−1, 1], where 1 means that the target subregion and the candidate subregion are completely similar; -1 means that the target subregion and the candidate subregion are completely dissimilar; and 0 means that there is no obvious linear correlation between the target subregion and the candidate subregion.

[0075] In some embodiments, a target area can be selected in the previous frame image and divided into a uniform grid. Each grid unit represents a small area of ​​the bubble. In the next frame image, a rectangular area of ​​a certain size can be selected as a candidate area, and the candidate area is traversed and searched with candidate sub-areas of the same size as the target sub-area, and the correlation coefficient between each candidate sub-area and the target sub-area is calculated. In the candidate area, the candidate sub-area with the largest correlation coefficient value is found, and the candidate sub-area is the associated target sub-area with the maximum correlation. The displacement of the target sub-area is obtained based on the coordinate difference between the center position of the most associated target sub-area and the target sub-area. Repeat the above steps for each target sub-area to obtain the displacement data of all target sub-areas.

[0076] A plurality of associated target sub-regions are combined to obtain an associated target region. A specific point, such as a center point, can be selected from the target region and the associated target region. The overall displacement of the bubble in two adjacent frames of images is calculated based on the center point of the target region and the center point of the associated target region. The instantaneous velocity of the bubble in each frame of the image is calculated based on this. The instantaneous velocity represents the global velocity of the bubble.

[0077] At the same time, based on the displacement data of all target sub-areas and the time interval between two adjacent frames of images, the instantaneous velocity of all target sub-areas can be obtained. The instantaneous velocity represents the local velocity of the bubble. By visualizing the instantaneous velocity of all target sub-areas, the movement law of the bubble can be intuitively understood.

[0078] Figure 3a and Figure 3b The positions of two different groups of bubbles in two adjacent frames of images and the corresponding instantaneous velocity visualization images according to an embodiment of the present disclosure are schematically shown.

[0079] like Figure 3a and Figure 3b As shown in the figure, the previous frame and the next frame show the position of the bubble at different time points. The grid calibration coordinate system provides a spatial reference system for displacement calculation, which helps to improve the measurement accuracy and ensures that the pixel displacement between two adjacent frames can be directly converted into physical displacement. The visualization image of instantaneous velocity shows the instantaneous velocity of the bubble movement, and the colors represent different speeds: the red area represents the high-speed area, and the blue area represents the low-speed area, which can intuitively show the local and global motion characteristics of the bubble.

[0080] According to the embodiments of the present disclosure, by dividing the target area into multiple target sub-areas and then using the correlation coefficient to determine the associated target sub-area with the maximum correlation with the target sub-area of ​​the previous frame image, the changes of the target sub-area in consecutive frame images can be accurately tracked. Even if the target area undergoes a certain deformation in the consecutive frame images, the most matching associated target sub-area can still be found by calculating the correlation coefficient, thereby improving the tracking accuracy and the robustness of the matching.

[0081] According to an embodiment of the present disclosure, the total displacement of the bubble includes the total displacement of each sub-region of the multiple target sub-regions; based on the average speed of the bubble, the preset time period, and the total displacement of the bubble in multiple consecutive frames of images, the microscopic deformation of the bubble is determined, including: determining the total displacement of the bubble in the first frame of image without deformation according to the average speed and the preset time period. Determine the microscopic deformation of the bubble according to the total displacement of each sub-region of the multiple target sub-regions of the bubble and the total displacement of the bubble in the first frame of image without deformation.

[0082] Without considering the bubble deformation, the total displacement of the bubble in the preset time period can be calculated by multiplying the average speed by the preset time period. The total displacement represents the theoretical total displacement of the bubble if it remains unchanged.

[0083] The total displacement of each of the multiple target sub-regions represents the actual total displacement of the bubble boundary of each part of the deformed bubble. The total displacement of each of the multiple target sub-regions can be accumulated based on the displacement of the target sub-region and the associated target sub-region in each of the two adjacent frames of images.

[0084] The microscopic deformation amount of the bubble boundary of each part of the bubble is obtained by using the difference between the total displacement of each sub-region of the multiple target sub-regions and the total displacement of the bubble in the first frame image without deformation.

[0085] By comparing the sub-region displacement with the total displacement, the microscopic deformation of the bubble during movement can be revealed, providing valuable information for the dynamics study and application of the bubble.

[0086] Figure 4 A schematic diagram of a bubble measurement system according to an embodiment of the present disclosure is schematically shown.

[0087] The present disclosure also provides a system for bubble measurement, such as Figure 4 As shown, the system includes an electronic device, a bubble generating device 1 and a camera 2. The electronic device is used to perform the steps of the above method. The bubble generating device is adapted to generate bubbles and accommodate the movement of the bubbles in response to a control instruction sent by the electronic device. The camera is adapted to capture images of the bubble movement and send the images to the electronic device.

[0088] In some embodiments, the electronic device may include one or more processors and a memory. The memory is used to store one or more computer programs, and the one or more processors execute the one or more computer programs to implement the above-mentioned bubble measurement method.

[0089] In some embodiments, the camera device 2 may be a high frame rate portable camera device, such as a mobile phone or a camera with a high frame rate shooting effect.

[0090] According to the embodiments of the present disclosure, Figure 4 As shown, the bubble generating device 1 includes a transparent container 11 and a calibration panel 12. A sealed cavity is formed in the transparent container 11, and the sealed cavity is suitable for receiving external water and forming bubbles using the gap outside the water. The calibration panel is drawn with a grid calibration coordinate system, which is set on the outer wall of the transparent container 11 and makes the grid calibration coordinate system face the camera device 2.

[0091] In some embodiments, the transparent container 11 may be a transparent water tank, a test tube or a plexiglass container, so that the movement path of the bubbles is clearly visible. The shape of the transparent container 11 may be cylindrical, square or other shapes suitable for experiments or observations.

[0092] In some embodiments, by injecting water into the sealed cavity of the transparent container and controlling the volume of the water, the volume of the remaining pores in the sealed cavity can be controlled, and the size of the bubbles can be controlled by using the volume of the remaining pores in the sealed cavity.

[0093] In some embodiments, the calibration panel 12 can be a permanent mark drawn directly on the outer wall of the transparent container 11, or a detachable sticker or panel so that it can be replaced or adjusted as needed. The grid calibration coordinate system can be two-dimensional, including horizontal and vertical lines, which are used to determine the position and movement trajectory of the bubble. In order to enhance the accuracy of the calibration, the lines on the grid calibration coordinate system can be designed to be equidistant, or designed to a specific scale according to the experimental requirements.

[0094] According to an embodiment of the present disclosure, the bubble generating device 1 provides a place for bubble generation and shooting that is convenient for shooting and calibration through a combination of a transparent container 11 and a calibration panel 12 .

[0095] According to an embodiment of the present disclosure, a background light source is further provided on a side of the calibration panel 12 facing the transparent container.

[0096] In some embodiments, the background light source may be an LED uniform planar light source to ensure uniform light distribution and avoid reflection or shadow interference.

[0097] In some embodiments, the distance between the background light source and the camera device 2 is appropriately adjusted to ensure that the bubbles and the grid calibration coordinate system can be clearly seen in the video. The high-speed photography mode of the high-frame rate portable camera device is fixed (such as using 960 fps or higher) so that the lens is perpendicular to the direction of bubble movement. When shooting, ensure that the background network calibration coordinate system is included in the video for subsequent calibration.

[0098] Figure 5 The figure schematically shows a transparent container rotating according to an embodiment of the present disclosure.

[0099] According to the embodiments of the present disclosure, Figure 5 As shown, the bubble generating device mechanism 1 further includes a fixing frame 13. The fixing frame 13 is rotatably connected to the transparent container 11, and is suitable for rotating the transparent container 11 to make the bubble move in the opposite direction when the bubble moves to a preset position, so as to repeatedly capture images of the bubble movement.

[0100] In some embodiments, the fixing frame 13 can be made of a strong material, such as metal or plastic, to ensure its stability and durability. The connection between the fixing frame 13 and the transparent container 11 can be designed in the form of a bearing or a rotary joint to achieve smooth rotation. The fixing frame 13 can be connected to the middle position of the transparent container 11 to facilitate the rotation of the transparent container 11.

[0101] In some embodiments, a locking mechanism may also be provided on the fixing frame 13 to fix the position of the transparent container 11 when necessary to prevent the transparent container 11 from rotating freely.

[0102] The preset position may be a bubble movement position preset according to experimental requirements. The preset position may be a position where the bubble movement exceeds the network calibration coordinate system. The present disclosure is not limited thereto, and the preset position may also be determined by setting a mark or scale on the transparent container.

[0103] When the bubble moves to a preset position, the moving direction of the bubble can be changed by rotating the transparent container 11. The transparent container 11 can be rotated manually or automatically by an electric drive device.

[0104] According to the embodiments of the present disclosure, by rotatably connecting the fixing frame 13 with the transparent container 11, a flexible and convenient operation mode is provided, which facilitates repeated image acquisition and analysis of the same bubble, thereby obtaining highly accurate repeatable observation results of bubble velocity and deformation, and effectively solving the problem of difficult reproducibility of bubble velocity measurement.

[0105] In related technologies, a relatively complex ultra-high-speed video velocimetry (PTV) technology can be used to measure bubble velocity, but this method usually requires relatively complex and expensive equipment and data analysis software. According to the bubble measurement system of the embodiment of the present disclosure, a video of the movement of bubbles in water can be captured based on a high-frame rate portable camera device in high-speed photography mode, and displacement information can be extracted from multiple frames of images based on image displacement matching technology, thereby realizing the test of the average velocity and deformation of the bubbles, which has the advantages of low cost, easy operation, and easy promotion.

[0106] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A method for bubble measurement, characterized in that: include: Controlling the bubble generating device to generate a predetermined number of bubbles; Acquire a plurality of continuous frames of images collected by a camera device of the bubble making an upward movement in the water body within a preset time period; Determine the displacement and instantaneous speed of the bubble in each frame of image rising in the water body by using the position of the bubble in each of the multiple frames of image and the time interval between two adjacent frames of image; Smoothing the instantaneous speeds corresponding to each of the multiple frames of images to obtain an average speed of the bubble within a preset time period; Determine the microscopic deformation amount of the bubble based on the average speed of the bubble, the preset time period, and the total displacement of the bubble within the preset time period, wherein the total displacement is accumulated according to the displacement of the bubble rising in the water body in each frame of the image; as well as The measurement result of the bubble is obtained based on the average speed and microscopic deformation of the bubble in the preset time period.

2. The method according to claim 1, characterized in that The method of determining the displacement and instantaneous speed of the bubble in each frame of image rising in the water body by using the position of the bubble in each of the multiple frames of image and the time interval between two adjacent frames of image includes: Based on the bubble boundary, bubble matching is performed on two adjacent frames of images to determine the positions of the matched bubbles in the two adjacent frames of images; Based on the positions of the matched bubbles in two adjacent frames of images and the time interval between the two adjacent frames of images, the displacement and instantaneous speed of the bubbles in each frame of image rising in the water body are determined.

3. The method according to claim 2, characterized in that The multiple frames of images contain a grid calibration coordinate system; The method of determining the displacement and instantaneous speed of the bubble rising in the water body in each frame of image based on the positions of the matched bubbles in the two adjacent frames of image and the time interval between the two adjacent frames of image comprises: Using the grid calibration coordinate system, calibrate the positions of the matched bubbles in two adjacent frames of images to obtain the grid positions of the bubbles in the two adjacent frames of images for the grid calibration coordinate system, wherein the positions of the bubbles in the two adjacent frames of images represent the pixel positions in the pixel coordinate system; Determining the displacement of the bubble between two adjacent frames of images based on the grid positions of the bubble in the two adjacent frames of images respectively for the grid calibration coordinate system; and The instantaneous speed of the bubble is determined according to the displacement of the bubble between two adjacent frames of images and the time interval.

4. The method according to claim 2, characterized in that: The step of performing bubble matching on two adjacent frames of images to determine respective positions of the matched bubbles in the two adjacent frames of images includes: Determine a target area of ​​the bubble from a previous frame image, wherein the target area includes a bubble boundary of the bubble in the previous frame image; Based on the bubble pixels of the target area of ​​the bubble in the previous frame image, determining an associated target area matching the target area in the next frame image; Based on the target area and the associated target area, the positions of the matching bubbles in two adjacent frames of images are determined.

5. The method according to claim 4, characterized in that The determining, based on the bubble pixels of the target area of ​​the bubble in the previous frame image, an associated target area matching the target area in the next frame image comprises: Dividing the target area of ​​the previous frame image into a plurality of target sub-areas, wherein the target sub-areas include at least a portion of the bubble boundary; Determine the correlation coefficient between the target sub-region and each of the plurality of candidate sub-regions based on the bubble pixels of the target sub-region of each of the previous frame images and the bubble pixels of each of the plurality of candidate sub-regions of the next frame image; Determining, in the subsequent frame image, an associated target sub-region having the greatest correlation with the target sub-region of the previous frame image by using the plurality of correlation coefficients; and The associated target region is obtained according to the associated target sub-regions with multiple maximum correlations.

6. The method according to any one of claims 1 to 5, characterized in that: The total displacement of the bubble includes the total displacement of each of the plurality of target sub-regions; The determining of the microscopic deformation amount of the bubble based on the average speed of the bubble, the preset time period, and the total displacement of the bubble in the continuous multiple frames of images comprises: Determine, according to the average speed and the preset time period, a total displacement of the bubble in the first frame of image without deformation; The microscopic deformation amount of the bubble is determined according to the total displacement amount of each of the plurality of target sub-areas of the bubble and the total displacement amount of the bubble in the first frame image without deformation.

7. A system for measuring bubbles, characterized in that: include: An electronic device for performing the steps of the method according to any one of claims 1 to 6; a bubble generating device adapted to generate bubbles and contain the movement of said bubbles; as well as A camera device is used to capture images of the bubble movement and send the images to the electronic device.

8. The system according to claim 7, characterized in that The bubble generating device comprises: A transparent container, wherein a sealed cavity is formed in the transparent container, and the sealed cavity is suitable for receiving external water and forming the bubbles by utilizing the gap outside the water; A calibration panel, on which a grid calibration coordinate system is drawn, is disposed on the outer wall of the transparent container so that the grid calibration coordinate system faces the camera device.

9. The system according to claim 8, characterized in that A background light source is also provided on a side of the calibration panel facing the transparent container.

10. The system according to claim 9, characterized in that The bubble generating device mechanism also includes: A fixing frame is rotatably connected to the transparent container and is suitable for rotating the transparent container to make the bubble move in the opposite direction when the bubble moves to a preset position, so as to repeatedly capture images of the movement of the bubble.

Images