基于旋转双棱镜的视场扩大方法和评价

Method and Evaluation of Enlarging Field of View Based on Rotational Double Prisms

旋转双棱镜系统可以通过光束控制来扩大成像视场、增大棱镜顶角,可提高视场角扩大倍率,但同时加剧成像畸变的问题。为了实现大视场实时成像的目的,针对大顶角双棱镜系统提出了一种快速畸变校正和视频拼接的方法。所提方法采用多次相机预标定、建立查表插值重投影算法,配合图像尺度变换及基于搜寻最佳缝合线的多分辨率融合算法,实现对两路旋转双棱镜成像系统的实时畸变校正和拼接。针对视场扩大情况,提出一种基于矢量形式折射定律的视场扩大评价方法,并以视场角扩大因子作为评价指标。仿真结果表明拼接视场水平视场角扩大因子可达1.50,垂直视场角扩大因子可达1.30。实验结果验证了该扩大视场方法的可行性,且可达到30frame/s的实时畸变校正及拼接。

The rotating double-prism system allows the expansion of the imaging field of view and increase of apex angle of prisms through beam control, therefore increasing the magnification of the field of view but aggravating imaging distortion. This paper proposes a fast distortion correction and video mosaic method for large-apex-angle double-prism systems to achieve real-time imaging with a large field of view. The real-time distortion correction and video mosaic of a two-way rotational double-prism imaging system are performed by multiple camera pre-calibrations, the construction of a table-lookup-based interpolation re-projection algorithm, and the application of a multi-resolution fusion algorithm with image scale transform based on the search for the optimal seam. For the expansion of the field of view, we propose an evaluation method of the expanded field of view based on the law of refraction in the vector form, and the field angle expansion factor is used as the evaluation index. The simulation results show that the horizontal and vertical field angle expansion factors of the mosaic field of view can reach 1.50 and 1.30, respectively. The experimental results verify the feasibility of the proposed method and achieve real-time distortion correction and video mosaic at 30 frame/s.