基于球面透视投影约束的全景环形透镜畸变校正

全景环形透镜将折反射面集成到一起,能无扫描地瞬时得到围绕光轴的360度超大视场,在机器人导航、视频监控和虚拟现实领域得到了广泛的应用.其成像机理是将围绕光轴的视场二次反射投影到环形平面上,图像存在严重的切向和径向畸变.本文根据全景环形透镜的特点采用基于球面透视投影模型对图像进行校正.首先建立含有畸变参量的全景环形透镜校正模型,将空间直线点映射为球面点,然后使用遗传算法将球面点拟合为球面上的最佳大圆,求出变形校正参量,进而校正全景环形像.仿真和真实图像实验表明,环形图像的切向和径向畸变得到了很好的校正.

Panoramic-Annular-Lens Distortion Correction Based on Spherical Perspective Projection Constraint

Panoramic annular lens (PAL) which integrates refraction lens and reflection mirror, can capture the super-view field of the entire 360° around the optical axis instantly. It is widely used in robot navigation, video surveillance and virtual reality. The imaging principle of PAL is to project the view field around the optical axis onto an annular plane through twice reflection. There is serious distortion in the tangential and radial directions on the image. A spherical perspective projection model is proposed to correct the image distortion according to the imaging feature of PAL. Firstly, the PAL correction model which includes distortion parameters is constructed. The points on the spatial line are projected to the points on the sphere under this model. All spherical points are fitted to the best great circle by genetic algorithm. The distortion parameters are obtained during this procedure. Then the panoramic image is corrected. Simulation and real-image experiments demonstrate that the tangential and radial distortions are corrected greatly.