In order to achieve 3D reconstruction of low-contrast and weakly textured ocean wave surfaces, a new stereo matching method for ocean wave images is proposed. Firstly, the binocular imaging system is calibrated, and the stereo image pair is subjected to epipolar correction; then, the corrected image is evenly divided into blocks, and the strongest Moravec feature points in the divided area are extracted; finally, the pyramid image matching strategy is used, combining the minimum the quadratic matching method obtains sub-pixel stereo matching results. Compared with the traditional Moravec feature matching method, the proposed method has higher matching accuracy and shorter matching time.
The 3D ice shape online measurement in the icing growth process is an important means to improve the ability of icing wind tunnel tests. Solving the problem of measuring the cross-sectional profile of the transparent ice body is the basis for the 3D ice shape online measurement during the icing growth process. In this paper, aiming at the problem of incapable of clear imaging in line structured light measurement of transparent ice, a laser excitation radiation imaging method is proposed. The Infrared laser is used for ice excitation imaging, and the reflected light imaging in traditional line structured light measurement is converted into self-luminous imaging. The transparent ice body is clearly imaged, and the cross-sectional profile of the cylindrical ice body is measured, which lays the technical foundation for the further development of 3D ice shape online measurement during the icing growth process.
To solve the problem that the dew point water vapor content in a low-temperature wind tunnel spans six orders of magnitude and the dynamic range of dew point measurement is high, the dew point measurement technology of dualwavelength laser absorption spectrum is studied in this paper. Using the hitran2012 database, the dew point absorption spectrum is simulated. 1854nm laser is selected for high dew point measurement and 2626nm laser for low dew point measurement. Through the combination of two bands, the high dynamic dew point measurement in the range of - 100℃~30℃ is realized, which meets the requirements of the dew point measurement range of low-temperature wind tunnel, and the measurement error is less than 2℃.
High speed photography has been widely applied in explosion mechanics, fluid mechanics, and missile trajectory measurement. However, due to the limitation of electronic system bandwidth, it is difficult for electronic high-speed camera systems to capture high-resolution videos for a long time. To solve this problem, this paper proposes a Bernoulli compression sampling (BCS) based high-speed camera compression and least square regression (LSR) based reconstruction method. In the camera capturing process, a part of the pixels are dropped randomly to achieve fast highspeed camera image compression. In compressed image reconstructing, an image is treated as a 2D linear system.The dropped pixels are reconstructed with LSR upon known pixels. Experimental results show that these methods can achieve fast compression and high quality reconstruction for high-speed camera.
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