CN114778420A - Method and device for automatically counting algae - Google Patents

Abstract

The invention discloses a method and device for automatic counting of algae, which acquires multiple sub-videos, and the sub-videos are obtained by photographing the algae in the water samples flowing through the micro-channel chip through a microscope and a camera; The displayed algae concentration, and according to the algae concentration displayed in each sub-video, the real concentration of algae in the water sample is calculated. The present invention does not need to observe all the algae samples, only needs to observe some algae samples, the concentration of the algae in the surface water can be calculated according to the statistical law, and the disadvantage that the zoom camera cannot be used in video collection is overcome.

Description

Method and device for automatic counting of algae

technical field

The invention relates to the technical field of algae counting, in particular to a method and device for automatic counting of algae.

Background technique

The phenomenon of algal blooms in surface water from time to time seriously affects the safety of drinking water for the surrounding people. Therefore, timely and accurate counting of the number of algae in the water body can accurately judge the safety of the water body. The conventional method is to fix surface water samples containing algae with reagents, then concentrate them, and then manually count the concentrated samples under a microscope. This method is very time-consuming, so there is a certain lag in judging the actual safety state of the water body.

Since the artificial counting of algae in water bodies lags behind the actual needs of production, the use of artificial intelligence to assist the intelligent counting of algae has become an objective requirement. The current artificial intelligence-based methods are:

Option 1: Place the concentrated water samples after manual pretreatment on glass slides. The slide can be controlled by a computer in its position in space. The third eye can only use the objective lens and an external digital device (which can have a certain digital magnification capability) to obtain the morphology of the algae in the water sample. The digital device is used to automatically and continuously photograph water samples. Artificial intelligence technology is used to automatically count the algae in the captured photos. The disadvantage of this scheme is that it still needs cumbersome manual means to concentrate the water samples. Since the concentration of algae cells in the surface water is unknown, the concentration of algae cells in the concentrated water sample may be extremely high so that different algae overlap each other; at the same time, due to the problem of depth of field of the objective lens, all the algae below the objective lens cannot be photographed Therefore, this method cannot truly reflect the concentration of algal cells in surface water samples. This protocol cannot be used for online algal enumeration in the field due to the need for manual pretreatment of water samples.

Option 2: Pump the water samples that have been pretreated to remove impurities such as particulate matter into several channels. These channels are different in size and are suitable for algae of different sizes to pass through. By taking pictures of algae in different channels with different microscopes, and then counting the pictures with artificial intelligence, the counting results of algae in the water sample can be obtained. This solution is not suitable for water samples with high sediment content or algae agglomeration, otherwise the channel can be blocked. This protocol cannot be used for field online algal counts in inland surface waters. Mainly used for online counting of algae in seawater.

Option 3: Pump the water samples that have been pretreated to remove impurities such as particulate matter into several channels. The diameters of these channels are the same. After the peristaltic pump is used to simultaneously pump the water sample into these channels, the peristaltic pump stops working. A trinocular microscope with a movable stage and a zoomable stage is used to take pictures of algae in any channel, and then the obtained pictures are counted by artificial intelligence. The count results of all channels are compared with each other. The average of two similar results was used as the count result of algae in the water sample. The disadvantage of this scheme is that the number of water samples used is small, the uncertainty of the results is large, and it is time-consuming.

Option 4: The water sample does not need to be pretreated. Pump surface water directly into flow cytometry tubes measuring millimeters in size. There is a large amount of sheath fluid in the flow cytometry tube, which can maintain the water sample stably in the middle of the cell tube. At the same time, the algal cells in the water sample flow through the flow cytometry tube one by one. The algal cells are irradiated with laser light, and the algae are counted by analyzing the properties of forward light and scattered light. At the same time, it is also possible to take pictures of representative algae using ultra-high-sensitivity photosensitive elements after laser irradiation, so as to know the morphology of certain algal cells. The disadvantage of this scheme is that the photos taken can only be black and white, which is difficult to obtain high accuracy even with machine learning. Qualitative analysis of algae using laser, different algae can be confused with each other.

SUMMARY OF THE INVENTION

In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method and device for automatic counting of algae.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

According to the first technical solution of the present invention, a method for automatic counting of algae is provided, the method comprising:

Obtaining a plurality of sub-videos, the sub-videos are obtained by photographing the algae in the water samples flowing through the micro-channel chip through a microscope and a camera;

The algal concentration displayed in each sub-video is calculated by the following formula (1):

X _i =Y _i /(K·t·P) Formula (1)

Among them, t is the duration of the sub-recording, K is the flow rate of the water sample entering the microchannel chip, P is the probability that algae are captured by the camera in the microchannel chip, Y _i is the number of algae captured by the camera, where X _i is the calculated concentration of algae in the water sample when Y _i algae are measured within t time;

According to the algae concentration displayed in each video, the true concentration of algae in the water sample is calculated by the following formula (2):

where x is the true concentration of algae in the water sample, and E(X _{i )} is the mathematical expectation of Xi.

Further, the multiple video recordings are obtained by the following method: pumping the water sample into the microchannel chip, photographing the algae flowing in the microchannel chip through a microscope and a camera to obtain a video, and recording the video at the same time The interval is divided into N video recordings.

Further, the multiple sub-videos are obtained by the following method: pumping the water sample into the micro-channel chip, repeating multiple times to photograph the algae flowing in the micro-channel chip through a microscope and a camera within the time t to obtain the multiple sub-videos. Molecular video.

Further, the water sample is processed by the following method: separating inorganic particles and algae in surface water by precipitation, and dispersing the algae gathered together to form agglomerates by ultrasound or stirring.

Further, the water sample is processed by the following method: separating inorganic particles and algae in surface water by precipitation, and dispersing and diluting the algae gathered together to form agglomerates by ultrasound or stirring.

According to the second technical solution of the present invention, a device for automatic counting of algae is provided, the device includes a water sample storage unit, a sample injection tube, a syringe pump, a microfluidic chip, a camera acquisition unit and a control unit;

The water sample storage unit is used to store water samples, and the water sample storage unit is connected to the inlet end of the microfluidic chip through a sample injection tube, the injection tube is provided with the syringe pump, and the camera collects The unit is arranged on one side of the microfluidic chip, to photograph the algae in the water sample flowing in the microfluidic chip to obtain multiple videos. The camera acquisition unit at least includes a camera and a microscope, and the camera acquisition unit Signal connection with the control unit;

The control unit is configured to receive multiple sub-videos collected from the camera acquisition unit, and calculate the algae concentration displayed in each sub-video by the following formula (1):

X _i =Y _i /(K·t·P) Formula (1)

Among them, t is the duration of the sub-recording, K is the flow rate of the water sample entering the microchannel chip, P is the probability that algae are captured by the camera in the microchannel chip, Y _i is the number of algae captured by the camera, where X _i is the calculated concentration of algae in the water sample when Y _i algae are measured within t time;

According to the algae concentration displayed in each video, the true concentration of algae in the water sample is calculated by the following formula (2):

where x is the true concentration of algae in the water sample, and E(X _{i )} is the mathematical expectation of Xi.

Further, the camera collection unit collects the multiple video recordings by the following method: pumping the water sample into the microchannel chip, photographing the algae flowing in the microchannel chip through a microscope and a camera to obtain a video, and recording the The video is divided into N sub-records at the same time interval;

Further, the camera-collecting unit collects the multiple video recordings by the following method: pumping the water sample into the micro-channel chip, repeating multiple times through the microscope and the camera to conduct the algae flowing in the micro-channel chip within the time t. The multiple sub-videos are obtained by shooting.

Further, the device further includes a water sample pretreatment unit, the water sample pretreatment unit includes a sedimentation mechanism, an ultrasonic or agitation mechanism connected in sequence, and the sedimentation mechanism is used to separate the inorganic particles in the surface water from the algae and then remove the algae. It is delivered to the ultrasonic or stirring mechanism, which is used to break up the algae that have gathered together to form agglomerates.

Further, the water sample preprocessing unit further includes a dilution mechanism connected to the ultrasonic or stirring mechanism, and the dilution mechanism is used for diluting the water sample processed by the ultrasonic or stirring mechanism.

Compared with the prior art, the beneficial effects of the present invention are:

1) It is not necessary to observe all algae samples, but only some algae samples need to be observed, and the concentration of algae in the surface water can be calculated according to statistical laws. It overcomes the disadvantage that the zoom camera cannot be used during video capture.

2) Compared with the solution 1 mentioned in the background art: the flow of the water sample in the detection device is continuous, and the surface water can be continuously pumped into the micro-channel chip, without the need for the control system to control the syringe pump; Water samples are concentrated and samples are constructed on glass slides;

3) Compared with the solution 2 mentioned in the background art: there is only one flow channel and related hardware, and the hardware requirement is significantly reduced;

4) Compared with the solution 3 mentioned in the background art: there is no need to use a zoomable photographic device on the third eye of the microscope, nor a mechanical stage controlled by software, which significantly reduces the technical difficulty and cost, At the same time, there is no need to interrupt the working state of the injection pump.

5) Compared with the solution 4 mentioned in the background art: the counting and qualitative analysis of algae are not carried out by using complex photoelectric (laser) technology and high-sensitivity photosensitive elements, which significantly reduces the technical complexity.

Description of drawings

In the drawings, which are not necessarily to scale, the same reference numbers may describe similar parts in different views. The same reference number with a letter suffix or a different letter suffix may denote different instances of similar components. The drawings illustrate various embodiments generally by way of example and not limitation, and together with the specification and claims serve to explain the disclosed embodiments. Where appropriate, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Such embodiments are illustrative, and are not intended to be exhaustive or exclusive embodiments of the present apparatus or method.

Fig. 1 is a flow chart of a method for automatic counting of algae in an embodiment of the present invention;

2 is a schematic structural diagram of a device for automatic counting of algae in an embodiment of the present invention;

3 is a schematic structural diagram of a device for automatic counting of algae according to an embodiment of the present invention;

FIG. 4 is a schematic working diagram of the microfluidic chip in the embodiment of the present invention.

Detailed ways

Some of the embodiments listed below are only to better illustrate the present invention, but the content of the present invention is not limited to be applied to the listed embodiments. Therefore, those skilled in the art can perform non-essential improvements and adjustments to the embodiments according to the above-mentioned contents of the invention and apply them to other embodiments, which are still within the protection scope of the present invention.

An embodiment of the present invention provides a method for automatic counting of algae. As shown in FIG. 1 , the method starts from step S100 and acquires a plurality of sub-videos, and the sub-videos use a microscope to cooperate with a camera to measure the water samples flowing in the microchannel chip. The algae were photographed.

It should be noted that, the sub-recordings in this embodiment of the present invention may be each video that is cut equally from a continuous video recording at a preset time interval, or each video segment that is collected in sections through a microscope and a camera. The sub-video should contain at least image information of algae.

In some embodiments, the multiple video recordings are obtained by the following method: pumping a water sample into a microchannel chip, photographing the algae flowing in the microchannel chip through a microscope and a camera to obtain a video, and recording the video Divide the video into N parts at the same time interval.

In some embodiments, the multiple sub-videos are obtained by the following method: pumping the water sample into the microfluidic chip, repeating multiple times to photograph the algae flowing in the microfluidic chip within the time t through a microscope and a camera The multiple sub-videos are obtained.

In step S200, the algae concentration displayed in each sub-video is calculated by the following formula (1):

X _i =Y _i /(K·t·P) Formula (1)

Among them, t is the duration of the sub-recording, K is the flow rate of the water sample entering the microchannel chip, P is the probability that algae are captured by the camera in the microchannel chip, Y _i is the number of algae captured by the camera, where X _i is the calculated concentration of algae in the water sample when Y _i algae are measured within t time;

Finally, in step S300, according to the algae concentration displayed in each part of the video, the actual concentration of algae in the water sample is calculated by the following formula (2):

where x is the true concentration of algae in the water sample, and E(X _{i )} is the mathematical expectation of Xi.

In the embodiment of the present invention, the real concentration of algae specifically refers to the real concentration of a certain type of algae. Since the method proposed by the embodiment of the present invention can obtain high-definition video images, the real concentration of each algae in the water sample containing various algae can be calculated in combination with the image recognition technology. Specifically, it is assumed that there are a variety of algae in the water sample, namely A, B, C, and D. According to the size and shape of different algae, each algae A captured by the camera can be calculated through image recognition and comparison technology. The number of , B, C, D, each algae can be calculated according to formula (1) and formula (2) to obtain its corresponding true concentration.

In order to reduce costs, the microscope lens and the stage in the embodiment of the present invention are preferably fixed.

To avoid particles clogging the microchannels, the microchannel chips should be larger than the largest algae in surface water, but modest in size. For example, the microfluidic chip is 0.4mm high and 0.5mm wide.

In order to photograph the algae clearly and meet the requirements of the artificial intelligence technology for the clarity of the sample, the embodiment of the present invention intends to use a high-magnification objective lens, such as a 40X objective lens, with a camera mounted on the third eye to record the algae. The disadvantage of high magnification objectives is their small field of view. Due to the small field of view, it is difficult to record all algae within 0.5mm. Therefore, there is a certain probability that the algae flowing through the microfluidic chip will not be detected by the camera. In order to still accurately measure the number of algae in the water sample under this defect, the following theoretical demonstration is carried out in the embodiment of the present invention:

The algae in the water sample can flow through the microfluidic chip one by one after the pretreatment and dilution treatment and the lower flow rate of the water sample provided by the syringe pump. Without loss of generality, assume that there is only one species of algae in the water sample, and its concentration is x/L. The flow rate of the water sample entering the microchannel chip is KL/min, and the operation time is t min (that is, the duration of the sub-recording, the sub-recording records the flow image of the water sample for a preset operation time t), and the algae in the microchannel chip The probability of being captured by the camera is P. During the operation time, the number of algae captured by the camera is _Yi . Then, according to the measurement results, the concentration of the algae in the water sample can be calculated by the formula shown in formula (1).

If the water sample is continuously detected N times, then the mathematical expectation of Xi is equal to the true concentration x of the _algae in the water sample, namely

It can be seen that the water sample is continuously detected for a long time T min, and the long time is divided into N detection stages. As long as T and N are large enough, as long as the probability P can be determined in advance, even if the camera cannot fully cover the microscopic The width of the flow channel chip is also possible to accurately determine the exact concentration x of the algae. Due to the high magnification objective lens, this scheme can obtain clear images of algae.

Therefore, the concentration and classification of the algae can be accurately determined.

Since the water sample can be diluted, the flow rate of the water sample can be kept low. Even if there are many different algae in the water sample, as long as they enter the field of view of the microscope one by one and are captured by the high-definition microscope camera, the number of algae species in the water sample will be determined. The accuracy of this program will not be affected.

The corresponding P in the above formula is different for different algae. The determination can be made using a suspension of pure cultured algae with a known cell concentration as a water sample. Therefore, the above formula has operability.

The embodiment of the present invention also provides a device for automatic counting of algae. As shown in FIG. 2 , the device includes a water sample storage unit 1 , a sample injection tube 2 , a syringe pump 3 , a microfluidic chip 4 , and a camera acquisition unit 5 and the control unit 6 .

The water sample storage unit 1 is used for storing water samples, and the water sample storage unit 1 is connected to the inlet end of the microfluidic chip 4 through a sample injection tube 2, and the injection tube 2 is provided with the syringe pump 3. The camera collection unit 5 is arranged on one side of the microfluidic chip 4, so as to photograph the algae in the water sample flowing in the microfluidic chip 4 to obtain multiple sub-videos, the camera collection unit 5 At least a camera and a microscope are included, and the camera acquisition unit 5 is signal-connected to the control unit 6;

The control unit is configured to receive multiple sub-videos collected from the camera acquisition unit, and calculate the algae concentration displayed in each sub-video by the following formula (1):

X _i =Y _i /(K·t·P) Formula (1)

Among them, t is the duration of the sub-recording, K is the flow rate of the water sample entering the microchannel chip, P is the probability that algae are captured by the camera in the microchannel chip, Y _i is the number of algae captured by the camera, where X _i is the calculated concentration of algae in the water sample when Y _i algae are measured within t time;

According to the algae concentration displayed in each video, the true concentration of algae in the water sample is calculated by the following formula (2):

where x is the true concentration of algae in the water sample, and E(X _{i )} is the mathematical expectation of Xi.

It should be noted that, the "water sample storage unit" described herein may be specifically implemented as a water tank or other device having a space for accommodating water samples. The way of signal connection between the camera acquisition unit 5 and the control unit 6 includes at least one or a combination of connection through wire, connection through WiFi module, connection through Bluetooth module, and connection through 2G/3G/4G/5G module.

The control unit 6 may be a processor or a device equipped with a data processing chip. Among them, the processor may be a processing device including more than one general-purpose processing device, such as a microprocessor, a central processing unit (CPU), a graphics processing unit (GPU), and the like. More specifically, the processor may be a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a processor running other A processor with a combination of instruction sets. A processor may also be one or more special-purpose processing devices, such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal processor (DSP), a system on a chip (SoC), or the like. The device equipped with the data processing chip can be an office computer or a smart phone.

In some embodiments, the camera-collecting unit collects the multiple sub-videos by the following method: pumping the water sample into the micro-channel chip, and photographing the algae flowing in the micro-channel chip through a microscope and a camera to obtain a video , the video recording is divided into N video recordings at the same time interval;

In some embodiments, the camera acquisition unit acquires the multiple sub-videos by the following method: pumping the water sample into the microfluidic chip, repeating multiple times through the microscope with the camera to scan the microfluidic chip within the time t The multiple sub-videos are obtained by photographing the flowing algae.

In some embodiments, as shown in FIG. 3 , the device further includes a water sample pretreatment unit, and the water sample pretreatment unit includes a sedimentation mechanism 7 and an ultrasonic or stirring mechanism 8 connected in sequence, and the sedimentation mechanism 7 uses After the inorganic particles in the surface water are separated from the algae, they are transported to the ultrasonic or stirring mechanism 8, and the ultrasonic or stirring mechanism 8 is used to break up the algae gathered together to form agglomerates.

It should be noted that the precipitation mechanism 7 is a mechanism that can separate the inorganic particles and algae in the surface water and transport them to the ultrasonic or stirring mechanism 8 . For example, the settling mechanism 7 may be a settling tank. The sedimentation mechanism 7 can transport the water sample after sedimentation treatment to the ultrasonic or stirring mechanism 8 by means of pipeline transportation. The ultrasonic or stirring mechanism 8 indicates that it can be a mechanism that can realize the ultrasonic function alone or realize the stirring function alone or realize the ultrasonic and agitation at the same time. The ultrasonic mechanism that realizes the ultrasonic function alone, for example, an ultrasonic generator is arranged at the lower end of a box body, and the water sample in the box body is ultrasonicated to break up the algae gathered together to form agglomerates. The stirring mechanism alone realizes the stirring function, for example, a stirring tank or a stirring blade is arranged inside a container to stir the water sample inside the container, so as to break up the algae gathered together to form agglomerates. A mechanism to realize ultrasonic and stirring at the same time, for example, in a container, an ultrasonic generator is arranged at the bottom, and a stirring blade is arranged from the top, so as to use ultrasonic and mechanical stirring at the same time to break up the algae gathered together to form agglomerates.

In some embodiments, the water sample preprocessing unit further includes a dilution mechanism 9 connected to the ultrasonic or stirring mechanism, and the dilution mechanism 9 is used for diluting the water sample processed by the ultrasonic or stirring mechanism. The dilution mechanism 9 is any device that can realize the dilution of the water sample processed by the ultrasonic or stirring mechanism. For example, a common water tank with a water filling port, etc.

The technical effects of the device for automatic counting of algae in each embodiment of the present invention are basically the same as those of the previous method for automatic counting of algae, which will not be repeated here.

The following embodiments of the present invention will further illustrate the feasibility and innovation of the present invention in combination with specific experimental methods.

The device shown in Figure 3 was used. The microchannel is 0.5mm wide, 0.4mm high, and has an area of 2×10 ^-7 square meters. When the flow rate of the syringe pump is 0.002ml/min, and the flow rate of the liquid in the microchannel chip is 166μm/s, the time for the algae to flow through the field of view of the objective lens (ie, the field of view of the camera) is about 2 seconds.

Using a camera with a frame rate of 20fps is enough to capture the algae in the field of view within 2 seconds.

Restricted by the field of view of the eyepiece, the area of the image captured by the camera is 300 μm along the length direction and 220 μm perpendicular to the length direction. Therefore, the camera coverage is less than half the width of the microchannel. Therefore, the camera cannot cover the entire width of the runner, so there is a blind spot in the camera's camera range (Figure 4).

In order to count accurately, the camera sampling number N is taken 30 times, each sampling is 5 minutes, and the total sampling time is 150 minutes. The flow rate was 0.002 mL/min. The average number of algae detected within 5 minutes is 1. When the algae flows through the camera's field of view, the probability of being detected is 0.25. Then, according to the above formula, the concentration of the algae in the treated surface water shown in FIG. 1 is calculated as: 4×105/L.

The concentration of algae in this water sample is obtained by summing the concentrations of all algae.

The above description is intended to be illustrative and not restrictive. For example, the above examples (or one or more of them) may be used in combination with each other. For example, other embodiments may be utilized by those of ordinary skill in the art upon reading the above description. Additionally, in the above Detailed Description, various features may be grouped together to simplify the present disclosure. This should not be construed as an intention that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description by way of example or embodiment, with each claim standing on its own as a separate embodiment, and it is contemplated that these embodiments may be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims (10)

1. a method for automatic counting of algae, is characterized in that, described method comprises: Obtaining a plurality of sub-videos, the sub-videos are obtained by photographing the algae in the water samples flowing through the micro-channel chip through a microscope and a camera; The algal concentration displayed in each sub-video is calculated by the following formula (1): X _i =Y _i /(K·t·P) Formula (1) Among them, t is the duration of the sub-recording, K is the flow rate of the water sample entering the microchannel chip, P is the probability that algae are captured by the camera in the microchannel chip, Y _i is the number of algae captured by the camera, where X _i is the calculated concentration of algae in the water sample when Y _i algae are measured within t time; According to the algae concentration displayed in each video, the true concentration of algae in the water sample is calculated by the following formula (2):

where x is the true concentration of algae in the water sample, and E(X _{i )} is the mathematical expectation of Xi. 2. method according to claim 1, is characterized in that, obtain described multiple sub-recordings by the following method: The water sample is pumped into the microfluidic chip, and the algae flowing in the microfluidic chip are photographed by a microscope and a camera to obtain a video, and the video is divided into N sub-videos at the same time interval. 3. method according to claim 1, is characterized in that, obtain described multiple sub-recordings by the following method: The water sample is pumped into the microchannel chip, and the algae flowing in the microchannel chip are photographed repeatedly through a microscope and a camera within a time t to obtain the multiple video recordings. 4. The method according to any one of claims 1-3, wherein the water sample is processed and obtained by the following method: The inorganic particles in the surface water are separated from the algae by precipitation, and the algae gathered together to form agglomerates are broken up by ultrasound or stirring. 5. The method according to any one of claims 1-3, wherein the water sample is processed and obtained by the following method: The inorganic particles in the surface water are separated from the algae by precipitation, and the algae gathered together to form agglomerates are broken up and diluted by ultrasound or stirring. 6. A device for automatic counting of algae, characterized in that the device comprises a water sample storage unit, a sample introduction tube, a syringe pump, a microfluidic chip, a camera acquisition unit and a control unit; The water sample storage unit is used to store water samples, and the water sample storage unit is connected to the inlet end of the microfluidic chip through a sample injection tube, the injection tube is provided with the syringe pump, and the camera collects The unit is arranged on one side of the microfluidic chip, to photograph the algae in the water sample flowing in the microfluidic chip to obtain multiple videos. The camera acquisition unit at least includes a camera and a microscope, and the camera acquisition unit Signal connection with the control unit; The control unit is configured to receive multiple sub-videos collected from the camera acquisition unit, and calculate the algae concentration displayed in each sub-video by the following formula (1): X _i =Y _i /(K·t·P) Formula (1) Among them, t is the duration of the sub-recording, K is the flow rate of the water sample entering the microchannel chip, P is the probability that algae are captured by the camera in the microchannel chip, Y _i is the number of algae captured by the camera, where X _i is the calculated concentration of algae in the water sample when Y _i algae are measured within t time; According to the algae concentration displayed in each video, the true concentration of algae in the water sample is calculated by the following formula (2):

where x is the true concentration of algae in the water sample, and E(X _{i )} is the mathematical expectation of Xi. 7. The device according to claim 6, wherein the camera collection unit collects the plurality of sub-records by the following method: The water sample is pumped into the microfluidic chip, and the algae flowing in the microfluidic chip are photographed by a microscope and a camera to obtain a video, and the video is divided into N sub-videos at the same time interval. 8. The device according to claim 6, wherein the camera collection unit collects the plurality of sub-records by the following method: The water sample is pumped into the microchannel chip, and the algae flowing in the microchannel chip are photographed repeatedly through a microscope and a camera within a time t to obtain the multiple video recordings. 9. The device according to any one of claims 6-8, characterized in that, the device further comprises a water sample pretreatment unit, and the water sample pretreatment unit comprises a sedimentation mechanism, an ultrasonic wave or a stirring mechanism connected in sequence, The precipitation mechanism is used to separate the inorganic particles in the surface water from the algae and transport them to the ultrasonic or stirring mechanism, and the ultrasonic or stirring mechanism is used to break up the algae gathered together to form agglomerates. 10 . The device according to claim 9 , wherein the water sample pretreatment unit further comprises a dilution mechanism connected to the ultrasonic or stirring mechanism, and the dilution mechanism is used to process the ultrasonic or stirring mechanism. 11 . The water sample is then diluted.

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