基于变高单应的单目视觉平面测量方法  

Plane measurement method with monocular vision based on variable-height homography

作　　者：张振[1] 徐枫[1] 沈洁[1] 韩磊[1] 徐立中[1] 

机构地区：[1]河海大学计算机与信息学院,南京211100

出　　处：《仪器仪表学报》2014年第8期1860-1868,共9页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(61374019);中央高校基本科研业务费专项(2014B00714)资助项目

摘　　要：针对河流水面成像测速等应用中采用单台非量测相机的变高平面测量,提出一种基于变高单应的视觉测量方法。方法在三维透视投影模型的基础上,结合水位和比降系数描述的水面高程模型建立图像平面和待测水面间的变高单应关系,解决了现有平面单应方法中控制点布设和水面高程变化的难题。设计了一种像差修正的直接线性变换法求解变高单应,有效改善了非量测相机的测量精度。试验重点分析了存在弱控制的条件下控制点布设、畸变像差、水位误差和倾斜视角对方法的敏感性。结果表明,在控制场布设条件良好的情况下,方法的坐标解算精度可以达到5 mm以上,能够满足中小河流的水面成像测速需求。Aiming at the measurement of variable-height plane with single non-metric camera in applications such as river surface ima-ging velocimetry （RSIV）,a vision measurement method based on variable-height homography （VHH）is proposed.The VHH relation between image plane and water plane is established based on the 3-D perspective projection model and combining with the water surface elevation model described by the coefficients of water level and slopes.The difficulties of ground control point （GCP）deployment and water level variation remaining in existing methods based on planar homography are overcome.A distortion correction direct linear trans-form method is designed to solve the VHH,which efficiently improves the measurement accuracy of non-metric camera.The experiments emphatically analyze the sensitivities of GCP distribution,distortion aberration,water level error and tilt angle to the method under weak-ly controlled conditions.The results show that the coordinate calculation precision of the method can reach 5 mm under well deployed controlling field,which fulfills the requirement of RSIV for medium and small rivers.

关 键 词：单目视觉 平面测量 变高单应 直接线性变换 敏感性分析 

分 类 号：TH815[机械工程—仪器科学与技术]