Wave information retrieval from videos captured by a single camera has been increasingly applied in marine observation.However,when the camera observes ocean waves at low grazing angles,the accurate extraction of wave...Wave information retrieval from videos captured by a single camera has been increasingly applied in marine observation.However,when the camera observes ocean waves at low grazing angles,the accurate extraction of wave information from videos will be affected by the interference of the fine ripples on the sea surface.To solve this problem,this study develops a method for estimating peak wave periods from videos captured at low grazing angles.The method extracts the motion of the sea surface texture from the video and obtains the peak wave period via the spectral analysis.The calculation results captured from real-world videos are compared with those obtained from X-band radar inversion and tracking buoy movement,with maximum deviations of 8%and 14%,respectively.The analysis of the results shows that the peak wave period of the method has good stability.In addition,this paper uses a pinhole camera model to convert the displacement of the texture from pixel height to actual height and performs moving average filtering on the displacement of the texture,thus conducting a preliminary exploration of the inversion of significant wave height.This study helps to extend the application of sea surface videos.展开更多
The 40 Gbit/s optical solitons transmission system in photonic crystal fiber was investigated by fast Fourier transform method, and the maximum transmission distance of system was calculated numerically. By the eye pa...The 40 Gbit/s optical solitons transmission system in photonic crystal fiber was investigated by fast Fourier transform method, and the maximum transmission distance of system was calculated numerically. By the eye pattern of system, the transmission performances of system were studied. Results show that when polarization mode dispersion coefficient Dp is smaller than , the influence of the PMD on the transmission distance was neglectable. When the dispersion coefficient D is larger than 1.5 ps/km/nm, the transmission distance decreases rapidly. The positive or negative of three order group-velocity dispersion makes no differences on the system transmission.展开更多
基金The Key R&D Program of Shandong Province under contract No.2023CXPT101.
文摘Wave information retrieval from videos captured by a single camera has been increasingly applied in marine observation.However,when the camera observes ocean waves at low grazing angles,the accurate extraction of wave information from videos will be affected by the interference of the fine ripples on the sea surface.To solve this problem,this study develops a method for estimating peak wave periods from videos captured at low grazing angles.The method extracts the motion of the sea surface texture from the video and obtains the peak wave period via the spectral analysis.The calculation results captured from real-world videos are compared with those obtained from X-band radar inversion and tracking buoy movement,with maximum deviations of 8%and 14%,respectively.The analysis of the results shows that the peak wave period of the method has good stability.In addition,this paper uses a pinhole camera model to convert the displacement of the texture from pixel height to actual height and performs moving average filtering on the displacement of the texture,thus conducting a preliminary exploration of the inversion of significant wave height.This study helps to extend the application of sea surface videos.
文摘The 40 Gbit/s optical solitons transmission system in photonic crystal fiber was investigated by fast Fourier transform method, and the maximum transmission distance of system was calculated numerically. By the eye pattern of system, the transmission performances of system were studied. Results show that when polarization mode dispersion coefficient Dp is smaller than , the influence of the PMD on the transmission distance was neglectable. When the dispersion coefficient D is larger than 1.5 ps/km/nm, the transmission distance decreases rapidly. The positive or negative of three order group-velocity dispersion makes no differences on the system transmission.
