A method for rapid identification of heavy pollution period in pond aquaculture based on satellite remote sensing technology

Abstract

The present invention provides a method for quickly identifying the heavy pollution period of pond aquaculture based on satellite remote sensing technology, including: obtaining satellite remote sensing images of the target area; performing image preprocessing on the satellite remote sensing images to extract target data; analyzing the target data based on a first preset condition to identify the first pond breeding area; obtaining image information of the first pond breeding area within a set time, and performing difference analysis to determine multiple breeding stages of the first pond breeding area within the set time; and recording the image time that meets the second preset condition. Compared with the prior art, the present invention uses satellite remote sensing technology to provide a method for quickly identifying the heavy pollution period of pond aquaculture, which is more efficient and less costly than traditional survey methods, and can provide support for strengthening pollution prevention, daily monitoring and supervision of aquaculture.

Description

Technical Field

[0001] The invention relates to the field of environmental supervision, and in particular to a method for quickly identifying a pond aquaculture heavy pollution period based on satellite remote sensing technology. Background Art

[0002] Aquaculture is one of the basic agricultural industries in my country and also one of the pollution sources of environmental water bodies. With the rapid development of aquaculture in my country, the irregular development of aquaculture in some areas has had an adverse impact on the water environment quality of local river basins and sea areas. Strengthening the supervision of the ecological environment of aquaculture has become one of the areas in which my country has strengthened pollution prevention and control work more comprehensively and deeply.

[0003] Compared with industrial pollution prevention and control, aquaculture pollution prevention and control started late, and the regulatory foundation is particularly weak. There are prominent problems such as unclear data on marine aquaculture projects and unclear pollution discharge rules. A series of effective technical means are urgently needed to fill the gaps in related work on aquaculture pollution prevention and control. As a major breeding method, pond aquaculture has some varieties that usually discharge a small amount of sewage, but they have the characteristics of huge sewage discharge after harvest and pond cleaning, and the sludge at the bottom of the pond is sometimes easily polluted due to improper disposal. At present, some areas have been carrying out the above-mentioned investigation and supervision of the heavy pollution period of pond aquaculture, but the method adopted is only the traditional manual investigation and on-site inquiry method. The breeding ponds are large in number and generally distributed in lake systems and river seashores. The roads are muddy and the environment is harsh. Manual investigations require a lot of manpower but no material and financial resources. In addition, the time of each harvest or pond cleaning by farmers needs to be determined according to the growth situation. The time is not completely fixed, and monitoring and supervision are difficult. This urgently requires a more time-saving, labor-saving and low-cost technology to carry out investigations on pond aquaculture during the heavy pollution period. Summary of the invention

[0004] The invention provides a method for quickly identifying the heavy pollution period of pond aquaculture based on satellite remote sensing technology, so as to facilitate and quickly investigate.

[0005] The present invention provides a method for quickly identifying the heavy pollution period of pond aquaculture based on satellite remote sensing technology, comprising:

[0006] Obtain satellite remote sensing images of the target area;

[0007] Perform image preprocessing on satellite remote sensing images to extract target data;

[0008] Based on the first preset condition, the target data is analyzed to identify the first pond breeding area;

[0009] Obtaining image information of the first pond breeding area within a set time, and performing difference analysis to determine different breeding stages of the first pond breeding area within the set time;

[0010] The time of the image meeting the second preset condition is recorded.

[0011] Furthermore, the image preprocessing at least includes radiation calibration, atmospheric correction, and orthorectification.

[0012] Furthermore, the satellite remote sensing image is a multispectral image of the target area.

[0013] Furthermore, the first preset condition is a characteristic spectral index of the pond breeding area.

[0014] Furthermore, the analyzing the target data based on the first preset condition to identify the first pond breeding area includes:

[0015] Based on the first preset condition, identifying the target data;

[0016] Acquire first pond related information that meets a first preset condition, wherein the first pond related information includes spectral characteristic information of the first pond and spectral geometric shape characteristic information of the first pond;

[0017] The breeding area of ​​the first pond is determined based on the spectral characteristic information of the first pond and the spectral geometric shape characteristic information of the first pond.

[0018] Furthermore, the second preset condition is a pollution threshold spectrum index for pond aquaculture. If the second preset condition is met, it means that the pond aquaculture area is severely polluted at that time.

[0019] Furthermore, the second preset condition includes:

[0020] The near-infrared band reflectivity of the pond breeding area is greater than 0.1.

[0021] Furthermore, the atmospheric correction adopts the FLAASH model.

[0022] Furthermore, the second preset condition includes:

[0023] Determine the surrounding environment of the first pond breeding area, and identify whether there is a second water body area, wherein the second water body area is used to provide water resources to the first pond breeding area;

[0024] If there is a second water body area, image information of the second water body area is obtained, and second spectral feature information of the second water body area is extracted to obtain the spectral feature difference between the first pond breeding area and the second water body area;

[0025] If the spectral characteristic difference meets the preset threshold, the spectral characteristic information of the first pond breeding area is identified and processed to calculate the pollution situation.

[0026] Furthermore, the second preset condition also includes:

[0027] If the spectral feature difference does not meet the preset threshold, the identification and processing of the spectral feature information of the first pond breeding area is stopped, and the spectral feature difference is repeatedly obtained every unit time.

[0028] Compared with the existing technology, the present invention uses satellite remote sensing technology to provide a method for quickly identifying the heavy pollution period of pond aquaculture. Compared with traditional survey methods, it is more efficient and less costly, and can provide support for strengthening pollution prevention, daily monitoring and supervision of aquaculture. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flowchart of an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0032] In recent years, with the launch of a variety of high spatial resolution and high temporal resolution satellites, there are more and more sources of satellite images, which can achieve high-frequency monitoring of breeding areas and facilitate the timely detection of pond aquaculture pollution discharge. This method is more efficient and less costly than traditional manual survey methods, and can provide support for strengthening aquaculture pollution prevention, daily monitoring and supervision.

[0033] The embodiment of the present invention discloses a method for quickly identifying a pond aquaculture heavy pollution period based on satellite remote sensing technology, comprising:

[0034] Obtain satellite remote sensing images of the target area;

[0035] Among them, the staff can select a specific target area and use software and other methods to obtain satellite remote sensing images of the target area;

[0036] Perform image preprocessing on satellite remote sensing images to extract target data;

[0037] Among them, by preprocessing the satellite remote sensing image, the interference information (background data) of the target area is determined, so as to accurately determine the image changes of the target area in different time periods;

[0038] Based on the first preset condition, the target data is analyzed to identify the first pond breeding area;

[0039] Among them, the first preset condition is a characteristic condition of the pond breeding area. Through the first preset condition, the characteristic of the first pond breeding area can be identified to achieve accurate positioning;

[0040] Obtaining image information of the first pond breeding area within a set time, and performing difference analysis to determine multiple breeding stages of the first pond breeding area within the set time;

[0041] Among them, some pond aquaculture species (such as shrimp farming) usually have less sewage discharge, and only a small amount of water is replenished or replaced. However, during the harvest and pond cleaning period, the aquaculture water in the pond will be emptied, and the sewage discharge is very large. After drainage, the spectral characteristics of the aquaculture pond change from aquaculture water to pond material (soil or cement and other building materials). Through this difference analysis, multiple aquaculture stages in the first pond aquaculture area can be effectively identified;

[0042] The time of the image meeting the second preset condition is recorded.

[0043] Among them, the second preset condition is the threshold set for the spectral information of the heavy pollution period. If the second preset condition is met, it means that the area is in a heavy pollution period. Since there are obvious spectral differences between the aquaculture water body and the pond material, the changes in the spectral information of satellite remote sensing images at different times within the monitoring range can be extracted based on this, which plays a role in quickly identifying the heavy pollution period of pond aquaculture and realizing intelligent monitoring.

[0044] The embodiment of the present invention uses satellite remote sensing technology to provide a method for quickly identifying the heavy pollution period of pond aquaculture. Compared with traditional survey methods, it is more efficient and less costly, and can provide support for strengthening pollution prevention, daily monitoring and supervision of aquaculture.

[0045] Optionally, the image preprocessing includes at least radiation calibration, atmospheric correction, and orthorectification.

[0046] Among them, through radiation calibration, atmospheric correction, and orthorectification, the interference information such as atmosphere and radiation can be effectively eliminated, the background value of radiation can be determined, and the spectral information changes caused by pond pollution can be accurately obtained.

[0047] Optionally, the atmospheric correction adopts a FLAASH model.

[0048] Among them, the atmospheric correction step belongs to preprocessing, which must be carried out when analyzing each image and before the reflectance is extracted to be greater than 0.1.

[0049] Optionally, the satellite remote sensing image is a multispectral image of the target area.

[0050] Optionally, the first preset condition is a characteristic spectral index of the pond breeding area.

[0051] In particular, the analyzing the target data based on the first preset condition to identify the first pond breeding area includes:

[0052] Based on the first preset condition, identifying the target data;

[0053] Acquire first pond related information that meets a first preset condition, wherein the first pond related information includes spectral characteristic information of the first pond and spectral geometric shape characteristic information of the first pond;

[0054] The breeding area of ​​the first pond is determined based on the spectral characteristic information of the first pond and the spectral geometric shape characteristic information of the first pond.

[0055] Among them, the specific method for obtaining the first pond breeding area is:

[0056] 1. Extract water bodies based on spectral feature information. Extract areas with NDVI values ​​< 0.25 and near-infrared band reflectance less than 0.1, where the NDVI calculation formula is (near-infrared band reflectance - red light band reflectance) / (near-infrared band reflectance + red light band reflectance).

[0057] 2. Extract ponds from water bodies based on their geometric shape characteristics. Since ponds are regular rectangles, and water bodies such as oceans and rivers do not have this geometric feature, pond breeding areas can be extracted based on this feature.

[0058] Among them, since the pond will be cleaned after harvesting, all the water will be drained at this time and the water area will be reduced. By collecting the spectral characteristic information of the first pond and the spectral geometric shape characteristic information of the first pond, the pollution situation of the pond at different stages and the corresponding water area size can be effectively judged, which is convenient for calculating the pollution impact.

[0059] Optionally, the second preset condition is a pollution threshold spectral index for pond aquaculture. If the second preset condition is met, it means that the pond aquaculture area is severely polluted at that time.

[0060] In particular, the second preset condition includes:

[0061] The near-infrared band reflectivity of the pond breeding area is greater than 0.1.

[0062] Among them, the spectral reflectivity of aquaculture water is relatively low, generally much lower than other landforms. Under normal circumstances, aquaculture water has a strong reflectivity in the blue-green band, and strong absorption in other visible light bands, especially in the near-infrared band, where the absorption is the strongest and the reflectivity is the lowest, which is significantly different from the spectral reflectivity characteristics of the pond material. By setting the second preset condition that the reflectivity of the near-infrared band of the pond aquaculture area is greater than 0.1, the embodiment of the present invention can effectively identify the pollution stage of the pond, and then accurately determine the time of heavy pollution of the pond.

[0063] In particular, the second preset condition includes:

[0064] Determine the surrounding environment of the first pond breeding area, and identify whether there is a second water body area, wherein the second water body area is used to provide water resources to the first pond breeding area;

[0065] Among them, pond water can be provided by surface water resources such as rivers, or by groundwater resources or tap water. If there is a pollution problem in the river water around the pond, the traditional method of directly calculating the pollution degree of the pond water body will mistakenly cause the river water pollution problem to be classified as the pond body, resulting in misjudgment; Based on the above reasons, the embodiment of the present invention identifies the second water body area of ​​the surrounding environment of the first pond breeding area. The second water body area is used to provide water resources to the first pond breeding area, such as rivers, lakes, and if there is a second water body area, it is necessary to consider the second water body area. If there is no second water body area, only the first pond breeding area is imaged and judged (determine whether the near-infrared band reflectivity of the pond breeding area is greater than 0.1. If it is greater than 0.1, the second preset condition is met); It should be noted that there is a distance limit between the second water body area and the first pond breeding area. The distance limit value of the embodiment of the present invention does not exceed 2km;

[0066] If there is a second water body area, image information of the second water body area is obtained, and second spectral feature information of the second water body area is extracted to obtain the spectral feature difference between the first pond breeding area and the second water body area;

[0067] Among them, by distinguishing the second spectral characteristic information from the spectral characteristic information of the first pond breeding area, the spectral characteristic difference between the first pond breeding area and the second water body area can be identified. The spectral characteristic difference belongs to the pollution value caused by the main cause of the pond to the pond breeding. By obtaining the spectral characteristic difference, the cause of pollution caused by the water source can be effectively eliminated;

[0068] If the spectral characteristic difference meets the preset threshold, the spectral characteristic information of the first pond breeding area is identified and processed to calculate the pollution situation.

[0069] Among them, technicians can set the specific value of the preset threshold according to actual conditions. If the spectral characteristic difference meets the preset threshold, it means that the pond pollution is too high, and it is necessary to calculate the pollution situation, and obtain the severe pollution situation of the pond based on the spectral characteristic difference, and then determine the severe pollution period caused by pond farming behavior.

[0070] The embodiment of the present invention can effectively eliminate the pollution caused by the water source through the above method, and then accurately calculate the pollution problems caused by the breeding process.

[0071] In particular, the second preset condition also includes:

[0072] If the spectral feature difference does not meet the preset threshold, the identification and processing of the spectral feature information of the first pond breeding area is stopped, and the spectral feature difference is repeatedly obtained every unit time.

[0073] The staff can set the unit time according to work needs. The embodiment of the present invention sets the unit time to 48 hours. The current spectral feature difference is identified every 48 hours to accurately obtain the changes caused by the pond pollution.

[0074] The processing and packaging process after collecting pollution information in the embodiment of the present invention is as follows:

[0075] 1. Extraction of heavily polluted areas. The extracted areas with reflectance greater than 0.1 are heavily polluted areas. Identify their distribution and calculate the area size of the area.

[0076] 2. Calculation of sewage discharge: The amount of sewage discharged in a heavily polluted area can be calculated by multiplying the area of ​​the heavily polluted area by the depth of the pond.

[0077] To sum up, the embodiments of the present invention utilize satellite remote sensing technology to achieve accurate identification of the target area based on image preprocessing, quickly identify the target water body, and determine the changes in pollution of the water body in different time periods based on spectral information identification. This is more efficient and less costly than traditional survey methods, and can provide support for strengthening pollution prevention and control, daily monitoring and supervision of aquaculture.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the specification of this application, the technicians can still modify or replace the specific implementation mode of the present invention with equivalents, but these modifications or changes do not deviate from the scope of protection of the pending claims of the present application.

Claims

1. A method for rapid identification of heavy pollution period of pond aquaculture based on satellite remote sensing technology, characterized in that: include: Obtain satellite remote sensing images of the target area; Perform image preprocessing on satellite remote sensing images to extract target data; Based on the first preset condition, the target data is analyzed to identify the first pond breeding area; Obtaining image information of the first pond breeding area within a set time, and performing difference analysis to determine multiple breeding stages of the first pond breeding area within the set time; Recording the time of the image meeting the second preset condition; The second preset condition is a pollution threshold spectrum index for pond aquaculture. If the second preset condition is met, it means that the pond aquaculture area is severely polluted at that time. The second preset condition includes: The near-infrared reflectivity of the pond breeding area is greater than 0.1; Determine the surrounding environment of the first pond breeding area, and identify whether there is a second water body area, wherein the second water body area is used to provide water resources to the first pond breeding area; If there is a second water body area, image information of the second water body area is obtained, and second spectral feature information of the second water body area is extracted to obtain the spectral feature difference between the first pond breeding area and the second water body area; If the spectral characteristic difference meets the preset threshold, the spectral characteristic information of the first pond breeding area is identified and processed to calculate the pollution situation; The second preset condition also includes: If the spectral characteristic difference value does not meet the preset threshold value, the identification and processing of the spectral characteristic information of the first pond breeding area is stopped, and the spectral characteristic difference value is repeatedly obtained every unit time; The distance between the second water body area and the first pond breeding area is no more than 2 km.

2. According to claim 1, a method for rapid identification of pond aquaculture heavy pollution period based on satellite remote sensing technology is characterized in that: The image preprocessing at least includes radiation calibration, atmospheric correction, and orthorectification.

3. According to claim 1, a method for rapid identification of pond aquaculture heavy pollution period based on satellite remote sensing technology is characterized in that: The satellite remote sensing image is a multispectral image of the target area.

4. According to claim 1, a method for rapid identification of pond aquaculture heavy pollution period based on satellite remote sensing technology is characterized in that: The first preset condition is the characteristic spectrum and geometric shape characteristic index of the pond breeding area.

5. According to claim 4, a method for rapid identification of pond aquaculture heavy pollution period based on satellite remote sensing technology is characterized in that: The analyzing the target data based on the first preset condition to identify the first pond breeding area includes: Based on the first preset condition, identifying the target data; Acquire first pond related information that meets a first preset condition, wherein the first pond related information includes spectral characteristic information of the first pond and geometric shape characteristic information of the first pond; The breeding area of ​​the first pond is determined based on the spectral characteristic information of the first pond and the spectral geometric shape characteristic information of the first pond.

6. According to claim 2, a method for rapid identification of pond aquaculture heavy pollution period based on satellite remote sensing technology is characterized in that: The atmospheric correction adopts the FLAASH model.

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