应用于水下能分辨粒径10μm^500μm尾流气泡的成像系统

Underwater imaging system identifying 10μm^500μm wake bubbles

针对尾流气泡成像存在的难点,采用片光源切片扫描与高速摄影相结合的技术手段,研制了一套水下激光成像系统。该系统采用激光片光照明,避免了尾流区气泡图像层叠;设计了3组倍率可切换镜头,实现了对大动态范围(10μm^500μm)粒径小气泡的成像;将镜头分成前后组,以平行光中继,通过片光与前镜组的同步移动,可实现尾流区一定体积内气泡图像的采样,同时还能保证扫描过程中始终成像清晰。此系统通过在海域进行试验,放置深度为5m,气泡由目标船产生,产生气泡粒径范围10μm^2 000μm,结果表明,系统成像效果良好,满足项目技术要求。

Considering ment system was presented based on the combination of high speed photography and laser sheet scanning technology. In this system, laser sheet was used to illuminate the wake zone to avoid the image stacking of bubbles. Because the particle size of bubbles was in a wide range three switchable magnification lenses were designed for the bubbles ima ging. Lenses were split into front and rear groups, with parallel rays transmitting between them. With the sweeping of laser sheet, the image information of bubbles in a volume could be sampled. Moreover, by keeping the front group moving synchronously with the laser sheet, bubbles could always image clearly when the laser sheet swept. The influence on image quali ty, the determination of laser sheet thickness and the system distortion correction, when laser sheet swept, were also discussed. The systems conducted a sea test at No. 760 institute of China ship building industry corporation（CSIC）, the depth of the sea was bubbles step from Objective test ship, the test results show that the image quality is good and this system satisfies technical requirements.