水下超视距百万像素距离能量相关三维闪光成像技术研究

Three dimensional range-intensity correlation imaging is a novel technique that will fill the current gap between short-range high-resolution conventional video cameras without 3D information and long-range low-resolution sonar systems, and it has great potentials in far fast high-resolution 3D sensing for the applications of underwater target detection and recognition, marine in situ detection, underwater vehicles navigation. In order to further extend the detection range of the technology and focus on solving the problem that the depth of field cannot be adjusted for fast high-resolution 3D imaging with large depth of field, the aim of this project is to develop 3D flash range-intensity-correlation megapixel imaging beyond underwater visibility range. By analyzing the impact of water inherent optic property and laser time-domain characteristics on detection range, range accuracy and resolution, a multi-pulse time delay integration method for adjusting depth-of-field to range-resolution ratio as well as a beyond-visibility-range detection enhancement method will be proposed to respectively realize pre-imaging time sequence optimization and post-imaging image enhancement for higher range resolution and accuracy and longer detection range. Furthermore, a fast super-resolution scanning method for large depth of field will be developed. The prototype experimental setup will be performed, and realize 3D flash imaging with >1000x1000 pixels at a frame rate of not less than 25Hz beyond underwater visibility range of 4.8 attenuation lengths.

距离能量相关三维成像是一种新型的三维成像技术，可填补水下摄像机（空间分辨率高但作用距离近、无三维信息）与水下声呐（作用距离远但空间分辨率低）间的技术空白，在水下目标搜寻识别、海洋原位探测、水下潜航器避障等远距离、快速、高分辨率三维探测感知应用中具有巨大技术潜力。为进一步提高该技术的作用距离，并重点解决成像景深不可调导致快速、大景深、高分辨率三维成像难的问题，本项目将开展超视距百万像素距离能量相关三维闪光成像技术的研究，分析水体光学特性及激光时域特性对成像距离、测距准确度和距离分辨率的影响，提出多脉冲延时积分景深距离分辨率比调节技术和超视距探测增强方法，通过成像前系统工作时序创新和成像后图像增强，提高距离分辨率、测距准确度和作用距离，并进一步提出大景深超分辨率快速扫描方法，搭建原理样机，实现探测距离大于水下视距（4.8个衰减长度）、帧频不小于25Hz、百万像素的超视距三维成像。

距离能量相关三维成像是一种新型的三维成像技术，可填补水下摄像机（空间分辨率高但作用距离近、无三维信息）与水下声呐（作用距离远但空间分辨率低）间的技术盲区，在水下目标搜寻识别、海洋原位探测、水下潜航器避障等远距离、快速、高分辨率三维探测感知应用中具有巨大技术潜力。为进一步提高距离能量相关三维成像技术在水下的作用距离，并重点解决成像景深不可调导致快速、大景深、高分辨率三维成像难的问题，本项目开展了超视距百万像素距离能量相关三维闪光成像技术的研究，分析了水体光学特性及激光时域特性对成像距离、测距准确度和距离分辨率的影响，提出了多脉冲延时积分景深距离分辨率比调节技术，重点开展了关联水体光学特性的去水体噪声计算成像、超像素空洞修复等超视距探测增强方法，通过成像前系统工作时序创新和成像后图像增强，提高距离分辨率、测距准确度和作用距离，并研制了原理样机，三维成像帧频25Hz@像素数1024×1024，最大探测距离达到6个衰减长度，大于水下视距4.8个衰减长度。本项目实质上实现了水下激光雷达相机，可以兼顾并超越传统激光扫描雷达与摄像机复合的技术方案，利用单一系统同时获得高对比度的二维强度图像和高分辨率的三维图像，为水下高分辨率光学成像提供了新的手段。