基于全方位视觉传感器的农业机械定位系统

利用全方位视觉传感器能提供传感器周围360°范围内信息的图像，通过全方位图像可准确获取物体方向角，基于该特点研发一种可以实现农业机械自动导航的定位系统。该系统硬件主要由全方位视觉传感器、人工标识、PC、PC软件和作业车构成。该计算算法首先通过全方位视觉系统的校正，得出相机的成像投影中心；通过图像处理提取人工标识的位置，估算出标识相对于相机的方向角，然后根据圆周角定理和几何关系计算出相机的位置来完成农业机械的定位。在面积为5×3 m2的水泥地面和白炽灯光的实验室中进行试验，平均选取10个位置进行试验，试验结果显示估算点和选取点间距离的平均误差小于3 cm。研究证明该定位系统是可行的。

Localization system of agricultural machinery based on omni-directional vision sensor

The omni-directional vision sensor can provide an image of 360 degree around the sensor and the directional angles of objects obtained from the image are relatively accurate. This study proposed a localization system for agricultural machinery navigation utilizing characters of omni-directional vision sensor. The system consisted of four artificial landmarks, an omni-directional vision sensor, PC, PC software and operating vehicle. The algorithm mainly included that the principal point of camera was obtained via calibration; the landmark positions were extracted by image processing to get the direction angles between landmarks from the image. Camera position was estimated according with circumferential theorem and geometric transformation based on the direction angles. Experiments were conducted on the level cement ground under daylight lamps in a 5 m×3 m rectangular area in the laboratory. Ten test positions were chosen equably. Results showed that the distance mean absolute error between estimated position and test position was less than 3 cm. In conclusion, the system is feasible.