A method and system for constructing an eutrophication index of water bodies

Abstract

The present invention provides a method and system for constructing a water eutrophication index, relating to the technical field of remote sensing monitoring. The method includes the following steps: obtaining remote sensing image data containing a target water body; processing the remote sensing image data to obtain the reflectance of multiple bands in the area where the target water body is located; constructing a water eutrophication index based on the reflectance of multiple bands. The present invention constructs corresponding water eutrophication indices respectively when the contrast between the target water body and the surrounding environment is obvious and not obvious, and corrects the water eutrophication index when the contrast is not obvious, providing a reference for the study of maintaining water integrity while improving the discrimination accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of remote sensing monitoring, and more specifically to a method and system for constructing a water eutrophication index. Background Art

[0002] At present, the enrichment of nitrogen and phosphorus nutrients in water bodies causes the rapid reproduction of algae and other plankton, resulting in a decrease in the dissolved oxygen in the water bodies and causing water pollution. Such water bodies are called eutrophic water bodies. And processing the remote sensing information of water bodies to obtain the corresponding water body index is one of the means for monitoring water body eutrophication.

[0003] However, in the prior art, a water body index is constructed based on the characteristics of several bands and the water body eutrophication evaluation is realized through the water body index. When the contrast between the water body and the surrounding environment is not obvious in different regions, due to the small number of bands applied, the difference in the overall spectrum may not be significant, and the water body index is not corrected, which affects the subsequent discrimination accuracy.

[0004] Therefore, how to provide a method for constructing a water eutrophication index that can solve the above problems is an urgent problem for those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method and system for constructing a water eutrophication index, which respectively construct corresponding water eutrophication indexes in the cases where the target water body is obvious and not obvious compared with the surrounding environment, and correct the water eutrophication index when the contrast is not obvious, providing a reference for the study of retaining water body integrity while improving the discrimination accuracy.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for constructing a water eutrophication index, comprising the following steps:

[0008] Obtain remote sensing image data including the target water body;

[0009] Process the remote sensing image data to obtain the reflectances of multiple bands in the area where the target water body is located;

[0010] Construct a water eutrophication index according to the reflectances of multiple bands.

[0011] Preferably, the specific processing process for obtaining the reflectances of multiple bands in the area where the target water body is located includes:

[0012] Preprocess the remote sensing image data;

[0013] Construct a classification model, input the preprocessed remote sensing image data into the classification model for recognition, and obtain the reflectance of the blue light band, the reflectance of the green light band, the reflectance of the near-infrared band, the reflectance of the short-wave infrared band of the target water body, and the reflectance of the blue light band, the reflectance of the green light band, the reflectance of the near-infrared band, and the reflectance of the short-wave infrared band of the non-water area adjacent to the target water body;

[0014] Visualize the reflectance of the blue light band, the reflectance of the green light band, the reflectance of the near-infrared band, the reflectance of the short-wave infrared band of the target water body, and the reflectance of the blue light band, the reflectance of the green light band, the reflectance of the near-infrared band, and the reflectance of the short-wave infrared band of the non-water area adjacent to the target water body.

[0015] Preferably, the specific process of constructing the water eutrophication index based on the reflectance of multiple bands includes:

[0016] Judge the relationship between the absolute value of the difference between the reflectance of the near-infrared band of the target water body and the reflectance of the near-infrared band of the non-water area adjacent to the target water body and the preset threshold;

[0017] If it is greater than or equal to, use the reflectance of the near-infrared band and the reflectance of the short-wave infrared band of the target water body to construct a water body index, and the specific expression is:

[0018] NDWI=(Green - NIR) / (Green + NIR)

[0019] In the formula, Green represents the reflectance of the green light band of the target water body, and NIR represents the reflectance of the short-wave infrared band of the target water body.

[0020] Preferably, the specific process of constructing the water eutrophication index based on the reflectance of multiple bands further includes:

[0021] If it is less than, use the reflectance of the blue light band and the reflectance of the green light band of the target water body to construct a water body index, and the specific expression is:

[0022] NDWI=(Blue - NIR) / (Blue + NIR)

[0023] In the formula, Blue represents the reflectance of the blue light band.

[0024] Preferably, it further includes:

[0025] When the absolute value of the difference between the reflectance of the near-infrared band of the target water body and the reflectance of the near-infrared band of the non-water area adjacent to the target water body is less than the preset threshold, correct the water eutrophication index.

[0026] Preferably, the specific process of correcting the water eutrophication index includes:

[0027] Obtain the meteorological parameters of the area where the target water body is located and the water quality parameters of the target water body;

[0028] Construct a correction model based on the meteorological parameters and the water quality parameters;

[0029] Correct the water eutrophication index according to the calculation result of the correction model.

[0030] Preferably, the meteorological parameters include: temperature, humidity and illuminance, and the water quality parameters include: dissolved oxygen, pH value and nitrogen content.

[0031] The present invention also provides a water eutrophication index construction system, including:

[0032] An acquisition module, configured to acquire remote sensing image data including a target water body;

[0033] A processing module, configured to process the remote sensing image data to obtain the reflectance of multiple bands in the area where the target water body is located;

[0034] A construction module, configured to construct a water eutrophication index according to the reflectance of multiple bands.

[0035] Through the above technical solutions, compared with the prior art, the present invention discloses a method and system for constructing a water eutrophication index, constructs corresponding water eutrophication indexes respectively when the contrast between the target water body and the surrounding environment is obvious and not obvious, and corrects the water eutrophication index when the contrast is not obvious, providing a reference for retaining the integrity research of the water body and improving the discrimination accuracy at the same time. Description of the Drawings

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0037] Figure 1 It is the overall flowchart of a method for constructing a water eutrophication index provided by the present invention;

[0038] Figure 2 It is the structural principle block diagram of a water eutrophication index construction system provided by the present invention. Detailed Embodiments

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] See Figure 1 As shown, an eutrophication index construction method for water bodies disclosed in an embodiment of the present invention includes the following steps:

[0041] Obtain remote sensing image data including the target water body;

[0042] Process the remote sensing image data to obtain the reflectance of multiple bands in the area where the target water body is located;

[0043] Construct an eutrophication index for the water body according to the reflectance of multiple bands.

[0044] In a specific embodiment, the specific processing process for obtaining the reflectance of multiple bands in the area where the target water body is located includes:

[0045] Preprocess the remote sensing image data, where the preprocessing process may include processes such as radiometric correction, atmospheric correction, and geometric correction to ensure the accuracy and comparability of the data;

[0046] Construct a classification model, input the preprocessed remote sensing image data into the classification model for identification, and obtain the reflectance of the blue band, green band, near-infrared band, and short-wave infrared band of the target water body, as well as the reflectance of the blue band, green band, near-infrared band, and short-wave infrared band of the non-water area adjacent to the target water body, where the classification model can be a convolutional neural network;

[0047] Visualize the reflectance of the blue band, green band, near-infrared band, and short-wave infrared band of the target water body, as well as the reflectance of the blue band, green band, near-infrared band, and short-wave infrared band of the non-water area adjacent to the target water body.

[0048] In a specific embodiment, the specific process for constructing an eutrophication index for the water body according to the reflectance of multiple bands includes:

[0049] Judge the relationship between the absolute value of the difference between the reflectance of the near-infrared band of the target water body and the reflectance of the near-infrared band of the non-water area adjacent to the target water body and a preset threshold;

[0050] If it is greater than or equal to, a water body index is constructed using the reflectance of the near-infrared band and the reflectance of the short-wave infrared band of the target water body. The specific expression is as follows:

[0051] NDWI = (Green - NIR) / (Green + NIR)

[0052] In the formula, Green represents the reflectance of the green light band of the target water body, and NIR represents the reflectance of the short-wave infrared band of the target water body.

[0053] In a specific embodiment, the specific process of constructing the water eutrophication index based on the reflectance of multiple bands further includes:

[0054] If it is less than, a water body index is constructed using the reflectance of the blue light band and the reflectance of the green light band of the target water body. The specific expression is as follows:

[0055] NDWI = (Blue - NIR) / (Blue + NIR)

[0056] In the formula, Blue represents the reflectance of the blue light band.

[0057] In a specific embodiment, it further includes:

[0058] When the absolute value of the difference between the reflectance of the near-infrared band of the target water body and the reflectance of the near-infrared band of the non-water area adjacent to the target water body is less than a preset threshold, the water eutrophication index is corrected.

[0059] In a specific embodiment, the specific process of correcting the water eutrophication index includes:

[0060] Obtain the meteorological parameters of the area where the target water body is located and the water quality parameters of the target water body;

[0061] Construct a correction model based on the meteorological parameters and the water quality parameters;

[0062] Correct the water eutrophication index according to the calculation result of the correction model.

[0063] In a specific embodiment, the meteorological parameters include: temperature, humidity, and illuminance, and the water quality parameters include: dissolved oxygen, pH value, and nitrogen content.

[0064] Specifically, the specific process of correction includes:

[0065] The meteorological parameters can be the average temperature, average humidity, and average light intensity in the area where the target water body is located within a preset time period;

[0066] Normalize the average temperature, average humidity, average light intensity, dissolved oxygen, pH value, and nitrogen content respectively. At the same time, establish the first correction model between the average temperature and dissolved oxygen, the second correction model between the average humidity and pH value, and the third correction model between the average light intensity and nitrogen content;

[0067] Perform weighted fusion on the first slope, second slope, and third slope corresponding to the first correction model, second correction model, and third correction model to obtain the corresponding coefficients. At the same time, perform weighted fusion on the normalized average temperature, average humidity, and average light intensity to obtain the corresponding meteorological coefficients, and perform weighted fusion on the normalized dissolved oxygen, pH value, and nitrogen content to obtain the corresponding water quality coefficients;

[0068] Perform weighted average fusion on the coefficients, meteorological coefficients, and water quality coefficients again to obtain the final correction coefficient, which is the calculation result of the correction model;

[0069] Use the correction coefficient to correct the water eutrophication index. By adding meteorological conditions and water quality conditions during the correction process, the contrast of the water body is enhanced when the contrast between the target water body and the non-target water body is not obvious, and the discrimination accuracy is improved.

[0070] See Figure 2 As shown, the embodiment of the present invention also provides a system using the method for constructing a water eutrophication index described in any one of the above embodiments, including:

[0071] An acquisition module for acquiring remote sensing image data containing the target water body;

[0072] A processing module for processing the remote sensing image data to obtain the reflectance of multiple bands in the area where the target water body is located;

[0073] A construction module for constructing a water eutrophication index based on the reflectance of multiple bands.

[0074] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0075] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for constructing a water eutrophication index, characterized in that: The following steps are involved: Acquire remote sensing image data containing target water bodies; The remote sensing image data is processed to obtain the reflectance of multiple bands of the target water body area. The specific processing process includes: Preprocessing the remote sensing image data; Constructing a classification model, inputting the preprocessed remote sensing image data into the classification model for identification, and obtaining the reflectivity of the blue light band, the green light band, the near infrared band, and the short-wave infrared band of the target water body, as well as the reflectivity of the blue light band, the green light band, the near infrared band, and the short-wave infrared band of the non-water body area adjacent to the target water body; Visualize the reflectivity of the blue light band, the green light band, the near infrared band, and the short-wave infrared band of the target water body, as well as the reflectivity of the blue light band, the green light band, the near infrared band, and the short-wave infrared band of the non-water body area adjacent to the target water body; The water eutrophication index is constructed based on the reflectance of multiple bands. The specific process includes: Determine the relationship between the absolute value of the difference between the reflectivity of the near infrared band of the target water body and the reflectivity of the near infrared band of the non-water body area adjacent to the target water body and a preset threshold; If it is greater than or equal to, the water body index is constructed using the reflectivity of the near-infrared band and the reflectivity of the short-wave infrared band of the target water body. The specific expression is: NDWI=(Green-NIR) / (Green+NIR) In the formula, Green represents the reflectivity of the green light band of the target water body, and NIR represents the reflectivity of the short-wave infrared band of the target water body; If it is less than, the water body index is constructed using the reflectivity of the blue light band and the reflectivity of the green light band of the target water body. The specific expression is: NDWI=(Blue-NIR) / (Blue+NIR) Where Blue represents the reflectivity of the blue light band.

2. A method for constructing a water eutrophication index according to claim 1, characterized in that: Also includes: When the absolute value of the difference between the reflectivity of the near infrared band of the target water body and the reflectivity of the near infrared band of the non-water body area adjacent to the target water body is less than a preset threshold, the water body eutrophication index is corrected.

3. A method for constructing a water eutrophication index according to claim 2, characterized in that: The specific process of correcting the water eutrophication index includes: Obtain meteorological parameters of the area where the target water body is located and water quality parameters of the target water body; Constructing a correction model based on the meteorological parameters and the water quality parameters; The water body eutrophication index is corrected according to the calculation result of the correction model.

4. A method for constructing a water eutrophication index according to claim 3, characterized in that: The meteorological parameters include: temperature, humidity and illumination; the water quality parameters include: dissolved oxygen, pH value and nitrogen content.

5. A system using the method for constructing a water eutrophication index according to any one of claims 1 to 4, characterized in that: include: An acquisition module, used for acquiring remote sensing image data containing a target water body; A processing module, used for processing the remote sensing image data to obtain the reflectivity of multiple bands of the area where the target water body is located; A building block used to construct a water eutrophication index based on the reflectance of multiple bands.

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