Red tide detection method based on AISA aerial hyperspectral image

Abstract

The invention relates to a red tide detection method based on an aerial hyperspectral image. Firstly, an aerial hyperspectral image of a sea area is measured by an airborne hyperspectral imager AISA; then digital quantization values of the wavelengths of 557-584 nm, 530-557 nm, 467 nm and 512 nm are selected from digital quantization values of the image wavelengths of 450-700 nm, and a curve area specific value between the digital quantization values of the wavelengths of 557-584 nm and 530-557 nm and a normalized blue-green waveband difference value between 467 nm and 512 nm are calculated; when the DN curve area specific value is greater than 1.077, and the normalized blue-green waveband difference value is smaller than 0.245, a picture element is a detected-out red tide picture element; and red tide picture elements which are connected into be in a flake shape or in a ribbon shape are decided as a red tide occurrence sea area. Directly according to the digital quantification values of the aerial hyperspectral image, radiometric calibration, atmospheric correction and other pretreatment on the image are not required, and definite and fast detection of red tide occurrence is achieved.

Description

technical field [0001] The invention relates to a red tide detection method based on an aerial hyperspectral image measured by an airborne hyperspectral imager AISA, and belongs to the field of image recognition. Background technique [0002] Red tide is a harmful ecological phenomenon that causes water discoloration caused by the rapid reproduction and accumulation of algae, some protozoa or bacteria in seawater under certain environmental conditions, also known as "water bloom" and "algal bloom". The occurrence of red tide not only destroys the normal ecological structure of the ocean, affects marine fishery resources, and deteriorates the marine environment, but also may poison marine economic animals and humans through the transfer and accumulation of food chains. Therefore, rapid and accurate detection of the occurrence of red tides plays an important role in its control and prevention, and in reducing its harm. [0003] Red tide monitoring mainly includes ship-borne o...

AI Technical Summary

Problems solved by technology

Although the detection of red tide occurrence, the estimation of plankton mass, and the identification of red tide dominant species have been realized based on hyperspectral images, preprocessing such as radiometric calibration and atmospheric correction must be performed on aerial hyperspectral images in these applications.

Among them, the radiation calibration needs to collect the dark current data of the hyperspectral imager synchronously, which increases the steps of on-site operation. At the same time, after the operator changes the band configuration and the frame rate integration time, it is easy to miss the dark current data collection. In addition, the optical properties of the water body in the sea area where the red tide occurs are complex, and the types of aerosols above it are changeable, coupled with the influence of gas absorption effects such as water vapor, carbon dioxide, and ozone, there is great uncertainty and complexity in atmospheric correction In addition, other objects in the ocean such as oil spills, green tides, sea ice, etc. can also interfere with the red tide detection of aerial hyperspectral images, causing misjudgment and affecting the accuracy of red tide detection. It fails to meet the needs of red tide emergency monitoring

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