Method and system for detection and analysis of foams on liquid surface

Abstract

This disclosure presents a method and system for detecting and analyzing foam on a liquid surface. The method includes: measuring multiple distances between multiple locations on the liquid surface and the depth photography device using a depth photography device and generating a depth map; obtaining a reference depth of the liquid surface; and calculating the foam height or foam coverage at multiple locations on the liquid surface based on the depth map and the reference depth.

Description

[Technical Field]

[0001] This disclosure relates to a method and system for detecting and analyzing foam on a liquid surface that can measure foam height and foam coverage. [Previous Technology]

[0002] In existing technologies, foam generation is a common problem widely found in water treatment facilities, chemical processes, food engineering, and biomedical engineering reaction processes. Foam is often caused by chemical reactions, gas escape, or biological activity, and tends to accumulate on the surface of liquids. Besides affecting visual appeal and reducing the image of facility management, its lightweight nature makes it highly susceptible to wind disturbance and diffusion into the surrounding environment. Furthermore, foam often carries inadequately treated pollutants or pathogens (such as bacteria and viruses), becoming a medium for airborne transmission and posing a potential threat to public health. In addition, foaming in culture and fermentation processes can sometimes adversely affect the process.

[0003] Currently, in most systems, foam control relies heavily on manual observation and reactive measures, including on-site operators noticing foam anomalies and then taking action, or passively accepting reports from third parties. However, in situations where there is no supervision or insufficient human resources, this reactive management model may lead to foam spreading without timely intervention, increasing the risk of pollution. Although some advanced systems have introduced camera monitors, these devices only have passive video monitoring capabilities and require human intervention to monitor the foam situation. [Summary of the Invention]

[0004] In order to solve the above problems, this disclosure proposes a method and system for detecting and analyzing foam on the liquid surface, which can automatically calculate the height of foam on the liquid surface and the coverage rate of foam on the liquid surface.

[0005] The embodiments disclosed herein propose a method for detecting and analyzing foam on a liquid surface, comprising: measuring multiple distances between multiple locations on the liquid surface and the depth imaging device using a depth imaging device and generating a depth map; obtaining a reference depth of the liquid surface; and calculating the foam height at multiple locations on the liquid surface based on the depth map and the reference depth.

[0006] The embodiments disclosed herein propose another method for detecting and analyzing foam on a liquid surface, including: measuring multiple distances between multiple locations on the liquid surface and the depth imaging device using a depth imaging device and generating a depth map; obtaining a reference depth of the liquid surface; and calculating the foam coverage rate of the corresponding liquid surface based on the depth map and the reference depth.

[0007] The embodiments disclosed herein provide a liquid surface foam detection and analysis system, including a depth photography device and a computing device. The depth photography device is used to measure multiple distances between multiple locations on the liquid surface and the depth photography device and to generate a depth map. The computing device obtains a reference depth of the liquid surface and calculates the foam height at multiple locations on the liquid surface based on the depth map and the reference depth.

[0008] In order to make the above-mentioned features and advantages disclosed herein more apparent and understandable, specific embodiments are described below, and detailed descriptions are provided in conjunction with the accompanying drawings.

Implementation Method

[0010] Some embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. Component symbols used in the following description are considered the same or similar components when they appear in different drawings. These embodiments are only a part of this disclosure and do not reveal all possible implementations of this disclosure. More precisely, these embodiments are merely examples of the systems and methods within the scope of this patent application.

[0011] The terms "first" and "second" used in this document do not specifically refer to order or sequence, but are used only to distinguish elements or operations described with the same technical terms.

[0012] Figure 1A is a schematic diagram illustrating a liquid surface foam detection and analysis system according to an embodiment. Referring to Figure 1A, the liquid surface foam detection and analysis system includes a computing device 130 and a depth imaging device 140, which are communicatively connected to each other. Furthermore, the containing device 110 contains a liquid 111, which may be sewage, a chemical solution, etc., and this disclosure does not limit the composition of the liquid 111. The liquid 111 has a liquid surface 111a. The depth imaging device 140 can be positioned directly above or diagonally above the containing device 110, and the field of view of the depth imaging device 140 will include at least a portion of the liquid surface 111a. The position of the computing device 130 is not limited. In this example, foam 112 will form on the liquid surface 111a. This liquid surface foam detection and analysis system can be applied to water treatment plants, food factories, chemical plants, or any type of factory, and this disclosure is not limited thereto.

[0013] The depth imaging device 140 is, for example, a time-of-flight (ToF) sensor, but in other embodiments it may also be an ultrasonic sensor, a structured light sensor, etc., which is not limited to this disclosure. The depth imaging device 140 is used to measure the distance between the liquid surface 111a (or the foam 112 on it) and the depth imaging device 140 and generate a depth map accordingly. For example, the depth imaging device 140 has a two-dimensional viewing angle range (e.g., 58 degrees * 87 degrees), so it can sense the distance (e.g., distance D3) between multiple locations within this viewing angle and the depth imaging device 140. If there is foam at this location, then distance D3 represents the distance between the foam and the depth imaging device 140; if there is no foam at this location, distance D3 represents the distance between the liquid surface 111a and the depth imaging device 140. The distances D3 at these locations can form a depth map.

[0014] The computing device 130 can be a personal computer, laptop computer, server, industrial computer, or any electronic device with computing capabilities. The computing device 130 can be used to obtain the reference depth D_rf of the liquid surface 111a. This reference depth D_rf can be obtained by other devices (e.g., level gauge 120) and transmitted to the computing device, or it can be manually input, or the deepest depth can be extracted from the depth map as the reference depth D_rf. When there is no foam on the liquid surface 111a, the depth imaging device 140 can measure the liquid level as the reference depth D_rf. If foam accumulates and covers the surface, the depth imaging device 140 cannot determine the liquid level, and the level gauge 120 must measure the reference depth D_rf, or a specific value can be manually input. That is, the level gauge is not a necessary component of the liquid surface foam detection and analysis system disclosed herein. The level gauge 120 can be a float-type level gauge, a pressure-type level gauge, an ultrasonic level gauge, a laser level gauge, or a radar level gauge; this invention is not limited to these types. Depending on the type of level gauge, the level gauge 120 can be positioned in different locations; the positions shown in Figure 1A are merely illustrative. For example, a float-type level gauge can be positioned within the receiving device 110 (i.e., the level gauge 120 is positioned below the liquid surface 111a) to measure the depth from the liquid surface 111a to the bottom of the receiving device 110. Since the distance between the depth imaging device 140 and the bottom of the receiving device 110 is known, a reference depth D_rf can be calculated based on this depth difference. Alternatively, the level gauge 120 can be positioned above the depth imaging device 140, or, for another example, between the liquid surface 111a and the depth imaging device 140.

[0015] Based on the aforementioned depth map and reference depth D_rf, the computing device 130 can calculate the foam height or foam coverage at multiple locations on the liquid surface 111a. For example, subtracting the distance D3 in the depth map from the reference depth D_rf yields the foam height at the corresponding location. The computing device 130 can check whether the foam height at each location is greater than a threshold value to determine whether there is foam at that location. When the foam height is greater than the threshold value, it indicates the presence of foam; conversely, when the foam height is less than or equal to the threshold value, it indicates the absence of foam (or such thin foam does not need to be considered). Accordingly, the computing device 130 can calculate the foam coverage. For example, if a total of N locations have their foam heights measured, and M of these locations have foam heights greater than the threshold value, the foam coverage can be M / N*100%, where M and N are positive integers, and M is less than or equal to N. In other embodiments, the depth map and reference depth D_rf can also be input into a machine learning model to segment out areas with foam and then calculate the foam coverage. Figure 1B is a schematic diagram illustrating the calculation of foam coverage based on a depth map according to an embodiment. Referring to Figure 1B, a depth map 190 is shown, where darker areas represent larger distances (D3). This process identifies the presence of foam at each location, and after binarization, a binary image 192 is generated, where white represents the presence of foam and black represents the absence of foam. The calculated foam coverage in the embodiment shown in Figure 1B is 81.25%.

[0016] In the above embodiment, the foam height and foam coverage can be calculated using the depth photography device 140. In the following embodiments, other devices such as image capturing devices are used in conjunction, but these image capturing devices are selectively used and not necessary.

[0017] Figure 1C is a schematic diagram illustrating a liquid surface foam detection and analysis system according to an embodiment. Referring to Figure 1C, the liquid surface foam detection and analysis system includes a containing device 110, a level gauge 120, a computing device 130, a depth imaging device 140, an image capturing device 150, a supplementary lighting device 160, and a foam removal device 170. Similarly, this liquid surface foam detection and analysis system can be applied to water treatment plants, food plants, chemical plants, or any other type of plant, and this disclosure is not limited thereto.

[0018] Figure 1C shows that the containing device 110 is, for example, a water tank, used to contain the liquid 111 to be monitored and analyzed. In some embodiments, the containing device 110 may be omitted. For example, the liquid surface foam detection and analysis system can be set up in places such as rivers, lakes, and ditches, where there is no containing device 110, or the liquid surface foam detection and analysis system can also be set up on a ship to detect and analyze foam on any body of water. In this embodiment, the level gauge 120 is, for example, an underwater level gauge; in other embodiments, the level gauge 120 can be a pressure level gauge or a bubble level gauge, which is not limited to this disclosure. The level gauge 120 is set in the containing device 110 and below the liquid surface 111a, thereby measuring the distance D1 between the level gauge 120 and the liquid surface 111a. Using the level gauge 120 can avoid measurement errors caused by liquid fluctuations or debris on the liquid surface 111a.

[0019] The computing device 130 is communicatively connected to the level gauge 120, the depth imaging device 140, the image capturing device 150, and the foam removal device 170. This communication connection can be achieved using any suitable wired or wireless communication means.

[0020] The depth imaging device 140 is used to measure the distance between the liquid surface 111a (or the foam 112 on it) and the depth imaging device 140 and generate a depth map accordingly. The depth map has been explained above and will not be repeated here.

[0021] The image capturing device 150 is used to capture an image toward the liquid surface 111a. This image may have multiple channels, such as red, green, and blue channels. In other embodiments, the image may have only one channel. The image capturing device 150 may include a charge-coupled device (CCD) sensor, a complementary metal-oxide-semiconductor (CMOS) sensor, or other suitable photosensitive element. In this embodiment, the image capturing device 150 is used to sense infrared light, but in other embodiments it may also sense visible light (or natural light), which is not limited to this disclosure. Using the image capturing device 150 can enhance the depth photography device 140 and improve the accuracy of calculating foam coverage, the calculation of which will be described in the following paragraphs.

[0022] The supplementary lighting device 160 is used to provide a light source to illuminate the liquid surface 111a when the image capturing device 150 captures an image. This supplementary lighting device 160 can be used with the image capturing device 150 to provide visible light or infrared light. When the image capturing device 150 senses infrared light (or visible light), the supplementary lighting device 160 provides infrared light (or visible light) as a supplementary light source. The supplementary lighting device 160 may include a light-emitting diode, a light source, or various light bulbs; this disclosure is not limited thereto. The supplementary lighting device 160 is used to provide a supplementary light source when the ambient light is low, thereby allowing the image capturing device 150 to capture a clearer image.

[0023] The foam removal device 170 is used to remove foam 112 from the liquid surface 111a. For example, the foam removal device may spray a pressurized liquid to break up or inhibit the formation of foam 112. In some embodiments, the foam removal device 170 has a spray nozzle, thereby allowing the foam removal device 170 to spray liquid onto the two-dimensional liquid surface 111a to physically eliminate foam. In some embodiments, the foam removal device 170 may also be used to add chemicals to chemically remove foam.

[0024] In the embodiment of FIG1C, the depth imaging device 140 and the image capturing device 150 can be integrated into one device. However, in other embodiments, the depth imaging device 140 and the image capturing device 150 can also be disposed in different devices. In some embodiments, the depth imaging device 140, the image capturing device 150, and the supplementary lighting device 160 can also be integrated into one device. Furthermore, in the embodiment of FIG1C, the depth imaging device 140, the image capturing device 150, and the supplementary lighting device 160 are disposed on the same crossbar, but in other embodiments, the depth imaging device 140, the image capturing device 150, and the supplementary lighting device 160 can also be disposed on different support structures. This disclosure does not limit the position of each component in FIG1C. Since the depth imaging device 140 and the level gauge 120 are pre-installed in the system, the preset distance D2 between the level gauge 120 and the depth imaging device 140 can be obtained by measurement.

[0025] The computing device 130 obtains the distance D1 between the level gauge 120 and the liquid surface 111a from the level gauge 120, and the distance D3 between the depth imaging device 140 and the liquid surface 111a (or the foam 112 on it) from the depth imaging device 140. Adding this to the preset distance D2 between the level gauge 120 and the depth imaging device 140, the computing device 130 can calculate the foam height D4 corresponding to a certain position. For example, subtracting distances D1 and D3 from the preset distance D2 yields the foam height D4, which can be expressed as the mathematical formula D4 = D2 - D1 - D3. Alternatively, calculating the absolute value of the difference between the preset distance D2 and distance D1 yields the reference depth D_rf (D_rf = |D2 - D1|) in Figure 1A. Similarly, when the level gauge 120 is positioned above the depth imaging device 140, the reference depth D_rf can be calculated in the same manner. Furthermore, when the level gauge 120 is positioned between the liquid surface 111a and the depth imaging device 140, the sum of the distance D1 between the level gauge 120 and the liquid surface 111a and the preset distance D2 between the level gauge 120 and the depth imaging device 140 can be calculated to obtain the reference depth D_rf.

[0026] Specifically, this disclosure discloses a method for detecting and analyzing foam on a liquid surface, wherein the step of calculating the foam height at a plurality of locations on the liquid surface includes measuring a first distance between the level gauge and the liquid surface using a level gauge, wherein the depth map includes a plurality of third distances between the depth imaging device and the locations; obtaining a second distance between the depth imaging device and the level gauge; calculating the absolute value of the difference between the second distance and the first distance to obtain a reference depth; and subtracting one of the third distances from the reference depth to obtain the foam height at a corresponding location on the liquid surface. When the level gauge is mounted on the depth imaging device, the reference depth can be calculated in the same manner. Furthermore, when the level gauge is positioned between the liquid surface and the depth imaging device, the reference depth can be obtained by calculating the sum of the first distance between the level gauge and the liquid surface and the second distance between the level gauge and the depth imaging device.

[0027] In some embodiments, the foam coverage rate can be calculated based on the image acquired by the image capturing device 150. FIG2 is a flowchart of calculating the foam coverage rate based on an image according to an embodiment. FIG3 is a schematic diagram of an image illustrating the calculation of the foam coverage rate according to an embodiment. Referring to FIG2 and FIG3, in step 201, an image is first acquired through the image capturing device 150. The image 310 acquired here includes a foam area 311 and a liquid surface area 312.

[0028] In step 202, a specific region (also called the region of interest, ROI) in the image is captured. Since the relative position between the image capturing device 150 and the receiving device 110 is fixed, and the viewing angle of the image capturing device 150 is also fixed, the specific region in the image can be determined in advance. In addition, an image without foam can be captured in advance as a reference image, and then the specific region is subtracted from this reference image pixel by pixel to obtain image 320. In image 320, the brighter pixels correspond to the foam region 311, while the darker pixels correspond to the liquid surface region 312. The grayscale of the pixels corresponding to the liquid surface region 312 will be close to 0 (becoming the darkest brightness).

[0029] In step 203, a filtering procedure is performed, for example, using Gaussian filtering to reduce noise in image 320. In step 204, a sharpening procedure is performed to enhance the edges in image 320. In step 205, a smoothing procedure is performed, for example, using median filtering. In other embodiments, steps 203-205 may be omitted, or only one or more of steps 203-205 may be performed.

[0030] In step 206, a specific region (i.e., image 320) is binarized according to a grayscale threshold value to obtain a binarized image 330. In this example, for each pixel in image 320, pixels with a grayscale threshold value less than the threshold value are set to the value "1" to obtain the liquid surface region 331, while pixels with a grayscale threshold value greater than or equal to the threshold value are set to the value "0" to obtain the foam region 332. In other embodiments, pixels with a grayscale threshold value less than the threshold value may be set to the value "0", and pixels with a grayscale threshold value greater than or equal to the threshold value may be set to the value "1", which is not limited to this disclosure. In this embodiment, the grayscale threshold value is a fixed value determined experimentally or manually, but in other embodiments it may be a dynamically determined value. For example, the histogram of image 320 can be calculated first, as shown in Figure 4, where the horizontal axis is the grayscale and the vertical axis is the number of pixels. Pixels corresponding to the liquid surface region will form a first peak 410, while pixels corresponding to the foam region will form a second peak 420. An unsupervised learning clustering method, such as k-means, can be performed here to divide these pixels into two clusters. The average of the centroids of the two clusters can be set to the grayscale threshold mentioned above. Alternatively, Otsu's method can be performed on the image 320, but this disclosure is not limited to this.

[0031] In step 207, the foam coverage rate is calculated based on the area of ​​the foam region 332 and the area of ​​the liquid surface region 331. Assuming the area of ​​the foam region 332 is A and the area of ​​the liquid surface region 331 is B, the foam coverage rate is A / (A+B)*100%, where A and B are real numbers.

[0032] Referring again to Figure 1C, the calculated foam coverage and foam height can be used to measure the severity of foaming. When the foam coverage or foam height is too high, a warning can be issued, or the foam removal device 170 can be activated. For example, when the foam height exceeds a height warning value and / or the foam coverage exceeds a coverage warning value, the computing device 130 transmits a warning message to the external device 180 via the Internet or other communication means, and the external device 180 displays the warning message on a graphical interface. This warning message can be presented using any text, image, or sound, and this disclosure is not limited thereto. In some embodiments, the computing device 130 may also record the calculated foam coverage and foam height in a database. In some embodiments, the computing device 130 may also generate a report based on the foam coverage and foam height monitored over a period of time, and provide it to relevant personnel for review. Alternatively, the computing device 130 may also provide a real-time monitoring screen, which users can view through the external device 180 or a mobile phone to obtain the real-time foam height and foam coverage.

[0033] In some embodiments, the liquid surface foam detection and analysis system may also include one or more water quality sensors. These water quality sensors are communicatively connected to the computing device 130 to measure water quality data such as dissolved oxygen, chemical oxygen demand (COD), aeration rate, pH value, temperature, conductivity, and air pressure in the liquid 111. This water quality data may also be recorded in a database. When the water quality data exceeds the warning value, the computing device 130 may also issue a warning message. Alternatively, the reports generated by the computing device 130 may also include this water quality data.

[0034] In some embodiments, the computing device 130 may also generate a control signal to the foam removal device 170 based on the foam height or foam coverage. For example, when the foam height is greater than a height warning value and / or the foam coverage is greater than a coverage warning value, the computing device 130 will set a control signal to activate the foam removal device 170, which will then remove the foam 112 on the liquid surface 111a by physical or chemical means.

[0035] Figure 5 is a flowchart illustrating a method for detecting and analyzing foam on a liquid surface according to an embodiment. Referring to Figure 5, in step 501, the distance between multiple locations on the liquid surface and the depth imaging device is measured by a depth imaging device, and a depth map is created. In step 502, a reference depth of the liquid surface is obtained. In step 503, the foam height at multiple locations on the liquid surface is calculated based on the depth map and the reference depth, or the foam coverage rate of the corresponding liquid surface is calculated. Each step in Figure 5 has been described in detail above and will not be repeated here. It is worth noting that each step in Figure 5 can be implemented as multiple pieces of code or circuits, and this disclosure is not limited thereto. Furthermore, the method in Figure 5 can be used in conjunction with the above embodiments or used alone; in other words, other steps can be added between the steps in Figure 5.

[0036] Figure 6 is a user interface for monitoring foam height according to one embodiment. Referring to Figures 1B and 6, the user interface is displayed on the external device 180, which includes a depth graph 610, a graph 620, a graph 630, and an indicator light 640. The horizontal axis of graph 620 represents time, and the vertical axis represents the foam height at a certain location (the height may be negative due to liquid fluctuations). The horizontal axis of graph 630 represents time, and the vertical axis represents the average foam height. The indicator light 640 is used to indicate whether the foam height exceeds a height warning value.

[0037] Figure 7 illustrates a user interface for monitoring foam coverage according to one embodiment. Referring to Figures 1B and 7, the user interface is displayed on the external device 180, which includes a real-time image 710, a graph 720, and an indicator light 730. The real-time image 710 is a color image captured by the image capturing device 150, used to observe the real-time situation on site. The horizontal axis of the graph 720 represents time, and the vertical axis represents the foam coverage. The indicator light 730 is used to indicate whether the foam coverage exceeds the coverage warning value. Through the user interface of Figures 6 and 7, the user can remotely check the foam height and foam coverage, and can also view the real-time image.

[0038] Figure 8 illustrates the results of the foam generation process according to an embodiment. Referring to Figure 8, foam was artificially generated in an experiment. The horizontal axis of graph 800 represents time, and the vertical axis represents foam coverage. The foam coverage at the first time point is 38%, corresponding to real-time image 810 and depth map 811; the foam coverage at the second time point is 86%, corresponding to real-time image 820 and depth map 821; the foam coverage at the third time point is 78%, corresponding to real-time image 830 and depth map 831; and the foam coverage at the fourth time point is 51%, corresponding to real-time image 840 and depth map 841. The graph and image results in Figure 8 demonstrate the correctness of the method used in calculating the foam coverage in the aforementioned disclosed embodiment.

[0039] This disclosure proposes a liquid surface foam detection and analysis system and method, which can automatically measure foam height and foam coverage, eliminating the cost of manual monitoring. When there is too much foam or the foam is too high, this system and method can also issue a warning in a timely manner or automatically remove the foam. When a level gauge is set to measure the reference depth, errors caused by liquid fluctuations can also be avoided.

[0040] Although this disclosure has been disclosed above with reference to embodiments, it is not intended to limit this disclosure. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the appended claims. [Simplified Explanation of the Diagram]

[0009] Figure 1A is a schematic diagram illustrating a liquid surface foam detection and analysis system according to an embodiment. Figure 1B is a schematic diagram illustrating the calculation of foam coverage based on a depth map according to an embodiment. Figure 1C is a schematic diagram illustrating a liquid surface foam detection and analysis system according to an embodiment. Figure 2 is a flowchart illustrating the calculation of foam coverage based on an image according to an embodiment. Figure 3 is a schematic diagram illustrating the calculation of foam coverage based on an image according to an embodiment. Figure 4 is a histogram illustrating a specific area according to an embodiment. Figure 5 is a flowchart illustrating a foam detection and analysis method according to an embodiment. Figure 6 is a user interface illustrating the monitoring of foam height according to an embodiment. Figure 7 is a user interface illustrating the monitoring of foam coverage according to an embodiment. Figure 8 is a diagram illustrating the relevant results of the foam generation process according to an embodiment.

Claims

1. A method for detecting and analyzing foam on a liquid surface, comprising: measuring multiple distances between multiple locations on a liquid surface and the depth imaging device using a depth imaging device and generating a depth map; obtaining a reference depth of the liquid surface; calculating the foam height corresponding to the locations on the liquid surface based on the depth map and the reference depth; and checking whether the foam height corresponding to each of the locations is greater than a threshold value to determine whether there is foam at the locations, thereby calculating a foam coverage rate.

2. The liquid surface foam detection and analysis method as described in claim 1, wherein the step of obtaining the reference depth of the liquid surface includes: The reference depth is obtained through a level gauge.

3. The liquid level foam detection and analysis method as described in claim 2, wherein the liquid level gauge is a float liquid level gauge, a pressure liquid level gauge, an ultrasonic liquid level gauge, a laser liquid level gauge or a radar liquid level gauge.

4. The liquid surface foam detection and analysis method as described in claim 2, wherein the step of obtaining the reference depth through the liquid level gauge includes: The first distance between the level gauge and the liquid surface is measured, and a second distance between the depth imaging device and the level gauge is obtained. When the level gauge is positioned below the liquid surface or above the depth imaging device, the absolute value of the difference between the first distance and the second distance is calculated to obtain the reference depth. Alternatively, when the level gauge is positioned between the liquid surface and the depth imaging device, the sum of the first distance and the second distance is calculated to obtain the reference depth.

5. The method for detecting and analyzing foam on the liquid surface as described in claim 1, wherein the step of calculating the foam height at certain locations on the liquid surface based on the depth map and the reference depth includes: Subtract the third distance between the positions on the liquid surface recorded by the depth map and the depth imaging device from the reference depth to obtain the foam height at the corresponding positions.

6. The liquid surface foam detection and analysis method as described in claim 5 further includes: An image is captured from the liquid surface by an image capturing device; a specific region of the image is captured; a reference image is subtracted from the specific region pixel by pixel; the specific region is binarized according to a grayscale threshold to obtain at least one liquid surface region and at least one foam region; and a foam coverage rate is calculated based on the area of ​​the at least one foam region and the area of ​​the at least one liquid surface region.

7. The liquid surface foam detection and analysis method as described in claim 6 further includes: After the specific region is captured and before the binarization process is performed, at least one of a filtering procedure, a sharpening procedure, and a smoothing procedure is performed on the specific region.

8. The liquid surface foam detection and analysis method as described in claim 6 further includes: When the height of the foam exceeds a height warning value or the coverage of the foam exceeds a coverage warning value, a warning message is sent to an external device, which then displays the warning message on a graphical interface.

9. A method for detecting and analyzing foam on a liquid surface, comprising: measuring multiple distances between multiple locations on a liquid surface and the depth imaging device using a depth imaging device and generating a depth map; obtaining a reference depth of the liquid surface; calculating the foam height at multiple locations on the liquid surface based on the depth map and the reference depth; and checking whether the foam height corresponding to each of the locations is greater than a threshold value to determine whether there is foam at that location, thereby calculating a foam coverage rate corresponding to the liquid surface.

10. The method for detecting and analyzing foam on a liquid surface as described in claim 9, wherein the step of calculating the foam height at certain locations on the liquid surface includes: A first distance between the level gauge and the liquid surface is measured by a level gauge, and a second distance between the depth imaging device and the level gauge is obtained. When the level gauge is positioned below the liquid surface or above the depth imaging device, the absolute value of the difference between the first distance and the second distance is calculated to obtain the reference depth. Alternatively, when the level gauge is positioned between the liquid surface and the depth imaging device, the sum of the first distance and the second distance is calculated to obtain the reference depth. The reference depth is then subtracted from the third distance between the positions on the liquid surface recorded by the depth map and the depth imaging device to obtain the foam height at the corresponding positions.

11. The liquid surface foam detection and analysis method as described in claim 9 further includes: When the height of the foam exceeds a height warning value or the coverage of the foam exceeds a coverage warning value, a warning message is sent to an external device, which then displays the warning message on a graphical interface.

12. A liquid surface foam detection and analysis system, comprising: a depth imaging device for measuring multiple distances between multiple locations on a liquid surface and the depth imaging device and generating a depth map; and a computing device communicatively connected to the depth imaging device for obtaining a reference depth of the liquid surface and calculating foam heights at the multiple locations on the liquid surface based on the depth map and the reference depth, wherein the computing device checks whether the foam height corresponding to each of the multiple locations is greater than a threshold value to determine whether there is foam at that location, and calculates a foam coverage rate accordingly.

13. The liquid surface foam detection and analysis system as described in claim 12 further includes: A level gauge is used to obtain this reference depth.

14. The liquid level foam detection and analysis system as claimed in claim 13, wherein the liquid level gauge is a float liquid level gauge, a pressure liquid level gauge, an ultrasonic liquid level gauge, a laser liquid level gauge or a radar liquid level gauge.

15. The liquid surface foam detection and analysis system as described in claim 12 further includes: A level gauge is used to measure a first distance between the level gauge and the liquid surface. A computing device is used to obtain a second distance between the depth imaging device and the level gauge. When the level gauge is positioned below the liquid surface or above the depth imaging device, the computing device calculates the absolute value of the difference between the first distance and the second distance to obtain a reference depth. Alternatively, when the level gauge is positioned between the liquid surface and the depth imaging device, the computing device calculates the sum of the first distance and the second distance to obtain the reference depth. The computing device subtracts a third distance between the reference depth and the depth imaging device from each of the positions to obtain the foam height at the corresponding positions.

16. The liquid surface foam detection and analysis system as described in claim 15 further includes: An image capturing device is used to capture an image onto a liquid surface, wherein a computing device is communicatively connected to the image capturing device to capture a specific region of the image, subtract a reference image from the specific region pixel by pixel, binarize the specific region according to a grayscale threshold to obtain at least a liquid surface region and at least a foam region, and calculate a foam coverage rate based on the area of ​​the at least one foam region and the area of ​​the at least one liquid surface region.

17. The liquid surface foam detection and analysis system as described in claim 16 further includes: A supplementary lighting device is used to provide a light source toward the liquid surface when the image capturing device captures the image.

18. The liquid surface foam detection and analysis system as claimed in claim 16, wherein after the specific region is captured and before the binarization process is performed, the computing device performs at least one of a filtering procedure, a sharpening procedure, and a smoothing procedure on the specific region.

19. The liquid surface foam detection and analysis system as claimed in claim 16 further includes an external device communicatively connected to the computing device, wherein when the foam height is greater than a height warning value or the foam coverage is greater than a coverage warning value, the computing device transmits a warning message to the external device, and the external device displays the warning message on a graphical interface.

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