High-Speed Imaging Detection System For Small Bubbles In Water And The Technology Studies Of Image Processing

Small scale bubbles are widely in ocean environment, the small bubbles produced by white, microorganism, ships sailing will greatly affect the optical properties of the water. A lot of work has around the tiny bubbles has been carried out, the research of the technology has positive significance for ship wake real-time detection, submarine pipeline and underwater equipment gas-tight testing. The main measurement of the underwater bubble is acoustics and optics, the optical methods consists of high-speed photography, laser hologram, the laser interferometer and laser scattering, all kinds of technology have different advantages, the high-speed photography method is simple, low cost, and can observe real-time state of bubbles.The thesis will introduce high-speed underwater imaging method for detection of underwater small scale air bubbles. Paper first studied the underwater imaging environment, the influence of light absorption and the backward scattering for the underwater imaging quality was analyzed, the theoretical model of bubble imaging was established. Secondly, in order to meet the design parameters, the device parameters of the system was calculated, and on this basis to determine the experiment scheme, build the bubble detection experiment platform and finished the experiment. Due to the actual bubble image were low contrast, The paper also discusses an experimental method of high-speed imaging for small bubbles in water, that is to get a cooperative target in the back of the bubbles, then shoot the bubbles, and the results of the two methods were compared. The experimental results show that the system can complete the underwater bubble detection task, can obtain real-time state of the bubble. The images are clearer and higher in contrast in the case of there is a cooperative target behind the bubbles, and with the imaging rate of the high-speed camera increases, the image quality is significantly reduced.Under certain conditions, the detection method for tiny air bubbles in water has some significance.In the study of image processing technology, based on the comparison of different filtering methods and different edge detection operators, Gaussian homomorphic filter were chosen as the filtering method of the system, Canny operator was been used to extract bubbles edge, used the gradient image to improve image visual effect, highlighted edge of the bubble.