多镜头全景摄像机球面视频无缝生成EI北大核心CSCD

针对多镜头全景摄像机MPC室内标定参数输出的实际场景球面全景视频存在视差伪影问题,提出一种场景自适应的球面全景视频无缝生成方法,主要包括两方面内容:①MPC球面投影参数最优估计。以实际场景视频重叠区域同名像点为观测值,通过最小化球面投影中心到同名像素对应球面空间点的夹角建立误差方程对球面投影参数进行最小二乘估计,从而降低子相机摄影中心与球面投影中心不重合及场景深度变化对MPC球面全景视频输出质量影响。②MPC球面全景视频生成TPS模型构建。以MPC子摄像机视频像素球面重投影几何为全局变换、以视频拼接线上同名像点为控制点建立TPS模型,实现MPC各子摄像机视频到球面拼接视频的像素直接映射,并能最小化视频重叠区域像素拼接误差,仅通过拼接线附近像素简单混合即可消除视差伪影并实现平滑过渡。模拟成像及实际场景试验结果表明,结合场景内容与摄像机内、外参数,本文方法可实现MPC球面全景视频无缝生成且计算简单、高效,完全满足MPC高帧率视频输出要求,具有良好的应用价值。

Seamless spherical video generation for multi-head panoramic camera(MPC)

Multi-head panoramic camera(MPC) is a kind of integrated optical system with ultra-wide field of view and can image an entire hemisphere onto a flat image plane through image stitching technique. But for actual scenes, the spherical video outputted by MPC often generates undesirable visual artifacts. This paper presents a method to generate seamless spherical video suitable for any scene. It mainly includes two aspects:① Estimation of MPC spherical projection parameters. Taking the tie points(pixels) detected in overlapping area as the observation values, those parameters are automatically estimated though minimizing the angle between the spherical projection center and corresponding spherical space points with the least square technique. As a result, the MPC video stitching errors caused by inaccurate calibration parameters, depth change of scene content and the inconsistency between MPC are effectively reduced; ② Establishment of TPS model for MPC spherical video generation. This model is established using the spherical re-projection geometry of MPC video pixels as global transformation and estimated with the salient pixels along selected seam line. As a result, video pixels of MPC sub-cameras can be directly mapped to the stitched spherical video with minimal pixel error in the overlapping area and the visual artifacts are completely eliminated simply by linearly mixing the pixels around selected seam line. The experimental results on stimulated and real scene show that, proposed method can generate seamless spherical Panoramic video for MPC used in various scene. In addition, proposed method is implemented efficient and can meet the requirements of high frame rate video output of MPC, and has good application value.