Identification of jellyfish in marine environment based on polarization

As a new Marine ecological disaster in the world, the inundation of jellyfish has seriously threatened the functions of Marine ecosystem. The body of jellyfish is mainly composed of water. It is composed of two layers, inner and outer. Between the two layers, there is a thick, transparent layer, which makes it difficult to detect jellyfish in the sea. In this article, sea jellyfish is realized by using the way of polarization imaging detection, setting the underwater imaging experiment device, using polarized light lighting actively, and using LED as light source. In the same time, the polaroid and wave plate experiments for different categories of polarized light, and a coaxial optical path to verify the polarization characteristics of background and target, to improve the image contrast. The polarization detector used in this paper can simultaneously image the polarization directions of 0°, 45°, 90° and 135°. In the experiment, four polarized images are fused, and the resulting image has a higher contrast ratio compared with the visible light intensity image and contains more detailed information.