融合结构光的折反射全景单目视觉测距

Catadioptric omnidirectional monocular visual distance measurement method integrating structured light

无人机在大机动运动时视场变化较大,在弱纹理环境下视觉特征易丢失,这降低了视觉距离测量的精度。针对此问题,本文将折反射全景相机与结构光相结合,进一步提出了融合结构光的折反射全景单目视觉测距方法。在本研究中,为了提高测距方法的精度以及处理速度,首先对结构光进行感兴趣区域(ROI)提取,并运用中值滤波对激光条纹图像进行去噪后,再采用改进的Steger算法进行亚像素级别的结构光光条中心坐标提取。其次,运用最小二乘原理对提取的亚像素点进行曲线拟合,得到结构光的曲线方程。最后,通过理论推导求取空间平面参数,建立测距目标函数,进一步求得距离信息。实验结果表明:在不同场景下,所提出测距方法的测距精度均在3%以内,证明了该方法的有效性。满足无人机在大机动运动条件下以及弱纹理场景中稳定可靠的测距需求,进一步提升了无人机环境感知能力。

The field of view of UAVs varies greatly during large maneuvering movements,and visual fea⁃tures are easily lost in weak texture environments,which greatly reduces the accuracy of visual ranging.To address this problem,this paper combined a catadioptric omnidirectional camera with structured light,and further proposed a catadioptric omnidirectional monocular visual ranging method with fused structured light.In this study,in order to improve the accuracy of the ranging method as well as the processing speed,the region of interest(ROI)of the structured light was first extracted and the median filter was ap⁃plied to denoise the laser streak image,and then the improved Steger algorithm was used for the extraction of the center coordinate of the structured light streak at the sub-pixel level.Second,the least squares prin⁃ciple was applied to curve-fit the extracted sub-pixel points to obtain the curve equation of the structured light.Finally,the spatial plane parameters were derived through theoretical derivation to establish the ranging objective function to further obtain the distance information.In different scenarios,the ranging ac⁃curacy of the proposed ranging method is within 3%,which proves the effectiveness of the method.It meets the demand for stable and reliable ranging of UAVs under large maneuvering conditions and weak texture scenes,and further improves the ability of UAVs to perceive the environment.