强散射噪声背景下弱光图像信号随机共振提取技术

The laser target imaging signal is easy confused by strong scattering noise in the case of remote transmission through the complex characteristics environment such as atmosphere and underwater, which lead to that the imaging signal is hidden by the same frequency scattering noise and cannot be identified by the conventional photoelectric detection technology. How to realize the extraction, enhancement and identification of the weak imaging signal from the strong scattering noise background has become the science community and research hotspot. This project aims to study the stochastic resonance technology based on spatial modulation instability to realize the extraction and identification of the weak imaging signal. Firstly, the generation mechanism of the scattering noise for the laser transmission in the complex characteristics environment should be theoretically explored, and the statistical distribution model of scattering noise should be built. Secondly, the physical mechanism of optical stochastic resonance via spatial modulation instability should be systematically investigated, and the theoretical model of using optical stochastic resonance technology to extract the weak imaging signal hidden by the strong scattering noise is necessary to be built. Finally, the weak imaging signal extraction and enhancement based on optical stochastic resonance technology for the strong scattering noise will be investigated experimentally. The output image with short response time and high image signal-to-noise ratio can be obtained for the optimization of system parameters. The study of this project will provide an effective technology support for the application areas, such as laser radar, laser remote sensing, oceanic monitor, and contribute to the rapid development of the related fields.

激光目标成像信号在通过大气、水下等复杂特征环境远距离传输时易受到强散射噪声干扰，使得图像信号被同频散射噪声湮没而难以被常规光电探测技术识别。如何实现强散射噪声背景下弱光图像信号的提取、增强和识别已成为当今世界上的科学难题和研究热点。本项目旨在研究基于空域调制不稳定性的光学随机共振技术，实现弱光图像信号提取和识别。首先，理论探究激光在复杂特征环境中传输时散射噪声的产生机制，建立散射噪声统计分布模型；其次，从理论上系统地研究空域调制不稳定性光学随机共振的物理机理，并建立应用光学随机共振技术实现强散射噪声背景下弱光图像信号提取的理论模型；最后，从实验上研究强散射噪声背景下随机共振弱光图像信号提取和增强技术，通过优化系统参数实现响应时间快、图像信噪比高的输出结果。本项目的研究将为激光雷达、激光遥感、海洋监测等应用研究领域提供有效的弱光图像信号提取、增强和识别技术，并促进这些领域的快速发展。

弱光图像重构技术是强散射环境下实现目标高质量、高精度探测和识别的关键技术手段之一，旨在提高散射环境下成像系统的探测能力，在激光雷达，空间光通信和远程光学遥感等领域有着重要应用。当光学图像传输通过混浊介质，吸收和散射会严重衰减图像信号的能量，产生大量的噪声。传统弱光成像技术基于噪声光和信号光的光学特性差异通过滤除噪声提高成像效果，然而当噪声强度远高于信号，以及噪声光和信号光的光学特性相近时，这些基于滤波的成像技术难以有效重构强噪声湮没的弱光图像。然而在某些特殊的非线性系统中，噪声的增强反而使得输出信噪比出现一定程度提升，即呈现随机共振现象。基于光学随机共振的弱光图像重构技术在非线性光学效应下能以耦合噪声的方式增强重构微弱图像信号。该技术有强的噪声图像复原能力，能有效处理与信号光特性相近的散射噪声。本项目围绕基于调制不稳定性的光学随机共振的物理机制和光学随机共振弱光图像重构，开展了基于交叉调制不稳定性、准粒子模型、混沌系统的空域调制不稳定性的机理研究，并分别建立了以背景加性噪声为主和以水下等散射介质产生的乘性噪声为主的弱光图像信号随机共振重构的物理模型，理论模拟了弱光图像信号在加性和乘性噪声湮没下的随机共振重构过程，并分析了各个关键参数的影响。实验搭建了基于强散射介质中乘性噪声的随机共振弱光图像信号重构实验装置，实现了被乘性噪声湮没的弱光图像信号的有效重构。在此基础上，开展了基于空域调制不稳定性随机共振的水下弱光图像重构的理论和实验研究，通过蒙特卡罗算法和准粒子模型分别模拟了光图像信号在浑浊水质下的传输特性和随机共振图像重构过程。实验研究了基于随机共振的浑浊水下弱光图像信号重构，实现了被前向散射噪声湮没的弱光图像信号的有效重构。同时探索了光学随机共振的新机理和新技术，提出利用光诱导光子晶体实现随机共振，证明了光诱导光子晶体能够抑制散射信号，重构噪声湮没图像信号。提出了利用液晶分子在外加电场、磁场下光诱导发生偏转而引起折射率变化的实现液晶中空域调制不稳定性引起的随机共振图像重构方法，以及液晶分子重定向效应引起的光学双稳态随机共振噪声湮没脉冲信号重构方法。本项目的研究结果为光学随机共振应用微弱光信号处理和成像探测等领域以及相关科学前沿、相关战略高技术与交叉学科的创新发展提供了关键理论和技术基础。