复杂场景下偏振导航自适应图像分割算法  

Self-Adaptive Image Segmentation Algorithm for Polarization Navigation under Complex Scenes

作　　者：周钰聪 叶超 林子涵 占春连 高涵 Zhou Yucong;Ye Chao;Lin Zihan;Zhan Chunlian;Gao Han(College of Optical and Electronic Technology,China Jiliang University,Hangzhou 310018,Zhejiang,China)

机构地区：[1]中国计量大学光学与电子科技学院,浙江杭州310018

出　　处：《光学学报》2024年第19期142-152,共11页Acta Optica Sinica

摘　　要：为了在多云天气或含有如建筑物、树木等遮挡物的复杂场景下实现无人机、汽车、船舶等移动载体快速、稳定、自适应的偏振导航定向,提出了一种基于蛇优化(SO)和最大类间方差(Otsu)算法的图像分割算法(SO-Otsu算法)。该方法直接对天空偏振度图像进行分割,通过设计二值化掩模提取有效的天空偏振信息,去除偏振信息中含有遮挡物的异常像素信息点。最后利用保留的有效像素信息点结合天空的瑞利散射模型解算太阳矢量,获得航向角,实现偏振导航定向。相较于传统Otsu算法,SO算法的引入,可以对偏振度图像进行快速自适应阈值计算,将航向角的解算时间有效地缩短了约40%。同时实验证明,该方法在树木、建筑等遮挡物的遮挡率范围为17%~83%的情况下,解算的航向角误差均方根小于0.75°,满足偏振导航的需求。Objective Due to Rayleigh scattering,the distribution pattern of polarized light in the sky varies regularly with the change in the position of the sun.Taking advantage of this distribution,polarized skylight navigation technology can achieve anti-interference and fully autonomous orientation and navigation with no cumulative error,making it widely applied in the areas of aerospace,military operations,and underwater navigation.However,under cloudy weather or complex scenes with obstructions such as trees and buildings,the polarization images of the obstructions do not obey the Rayleigh scattering principle.Therefore,directly using sky polarization images of complex scenes for navigation orientation will reduce navigation accuracy.To solve this issue,various imaging segmentation methods have been proposed for separating sky and occlusion information,but they still have some limitations.For example,the method of using neural networks for obstruction segmentation requires a large amount of data and time for training,making it hard for model application,diagnosis,and repair.Using polarization degree gradient as a threshold to extract effective polarization information often needs to set gradient thresholds manually and requires a large number of experiments,which lacks universality.Therefore,we propose an image segmentation algorithm(SO-Otsu)based on the snake optimization(SO)algorithm and the Otsu method to achieve fast,stable,and self-adaptive polarization navigation of mobile carriers such as drones,cars,and ships under cloudy weather or complex scenes with different obstructions.Methods Before applying the SO-Otsu algorithm to segment obstructions and sky in the polarization images for navigation accuracy improvement,the bilinear interpolation algorithm is first used to extract four images with different angles from images captured by a polarization camera.Then Stokes vectors are used to obtain the sky polarization degree image and polarization azimuth image.By using the Otsu algorithm,the maximum inter-class var

关 键 词：图像处理 偏振导航 定向 瑞利散射 OTSU算法 蛇优化算法 

分 类 号：V249.325[航空宇航科学与技术—飞行器设计]