Obtaining water-to-air panoramic images by inverse ray tracing method

The water-to-air images of sea surface and air targets through wavy surface will be distorted. In order to quantitatively analyze the effect of sea surface waveform on image distortion, an ideal water-to-air imaging model was established so as to obtain the panoramic image through the waveform. Firstly, based on the given imaging model, the main-ray inverse tracing method was used to calculate the direction vector of overwater refracted ray corresponding to the underwater incident ray by Snell’s law, and the corresponding relation of objective image between the target point on the celestial sphere and the single pixel point on the imaging target surface was obtained. Then, all the pixel points on the imaging target surface were traversed, and a water-to-air panoramic image was formed. Finally, based on the four kinds of special waveform, the water-to-air panoramic image of sky circular target and background was calculated in MATLAB environment. The calculation results show that the water-to-air panoramic image can be effectively calculated by the inverse ray tracing method and can be quantitatively analyzed the image distortion degree by adjusting the waveform parameters. The main-ray inverse tracing method is suitable for analyzing the distortion characteristics of the water-to-air panoramic image with first-order guided waves, which lays a foundation for studying the distortion characteristics of water-to-air image under more complex waves.