折反射成像的经纬仪模型研究

Study on Theodolite Model of Refraction and Reflection Imaging

折反射全向相机具有能够提供360°视场、安装灵活、结构紧凑、成本低廉等优势。在单视点结构的约束条件下,根据折反射成像的旋转对称性,提出了折反射成像的全新模型。首先,根据折反射成像的投影几何理论,分析并推导出图像点到投影中心之间的距离与空间射线俯仰角的对应关系。其次,根据现有的球面统一模型将空间点投影到图像平面上,得出的图像点坐标在提出的模型中反投影出一条空间射线,对比统一球面模型验证提出的模型的正确性。最后用提出的模型计算图像点的反投影误差,得到误差为0.2个像素以内,实验结果表明,提出的模型能够获得较高的标定精度。提出的经纬仪模型将二维标定化简为一维标定,为折反射全向视觉的研究开辟了新的思路。

Catadioptric omnidirectional camera has the advantages of 360°field of view,flexible installation,compact structure and low cost.Under the constraint of single view structure,according to the rotational symmetry of refraction imaging,a new model of refraction imaging is proposed.Firstly,based on the projecting geometrical theory of catadioptric imaging,the relationship between the pitch angle of spatial ray and the distance from the object to the projection center is analyzed and derived.Secondly,according to the existing spherical unified model,the space points are projected onto the image plane.The coordinates of the image points are projected back to a space ray in the proposed model,and the correctness of the model is verified by comparing the unified spherical model.Finally,the back projection error of image points is calculated with the proposed model,and the error is within 0.2 pixels.The experimental results show that the proposed model can achieve high calibration accuracy.The proposed theodolite model simplifies the two-dimensional calibration into one-dimensional calibration,which opens up a new idea for the research of catadioptric omnidirectional vision.