双半球型胶囊机器人弯曲肠道内视觉导航方法

Visual Navigation Method of Dual Hemisphere Capsule Robot inside Curved Intestine Tract

为了实现主被动模态双半球型胶囊机器人在肠道内转弯行走,提出了一种视觉导航方法,首先利用动态调姿模态时胶囊轴线与万向旋转磁场轴线的同轴随动特性,并结合同一俯仰角和两个不同侧摆角下单目摄像头所拍摄的两幅无线传输图像确定摄像头的姿态,然后在摄像机坐标系内提取摄像头对准弯曲肠道时图像的暗区质心像素位置,在万向均匀旋转磁场条件下结合摄像头的姿态信息,通过计算固定坐标系下弯曲肠道图像暗区质心的方位来确定胶囊的视觉导航方位,最终确定胶囊转弯滚动磁场轴线方向,以便实现胶囊在肠道内的视觉辅助导航作业。试验证明该方法可用于胶囊导航,不需要附加传感装置,胶囊结构紧凑,为实现胃肠环境内遍历检查与医疗作业奠定了基础。

To realize the steering locomotion of the dual hemisphere capsule robot with active and passive modes in curved intestinal tract, a visual navigation method is proposed. First, based on the coaxial follow-up characteristics of the capsule axis and the spatial universal rotating magnetic vector during dynamic posture adjustment process, the posture of the embedded monocular camera can be calculated by its two wireless transmission images taken at the same altitude angle but two different azimuth angles. Then, the centroid pixel coordinates of the dark region of the image can be extracted in the camera coordinate when the camera is aligned with the curved intestine, and under the condition of uniform spatial universal rotating magnetic field and by combination with the posture of the camera, the direction of visual navigation of the capsule is derived by calculating the orientation of the centroid of the dark region of the image in the fixed coordinate system, thus the visual navigation of the capsule in the curved intestine tract can be achieved by further calculating the direction of the the spatial universal rotating magnetic vector for rolling locomotion. The test proves that the method can be used for capsule navigation without any additional sensor device, with more effective load volume, the navigation method lays a foundation for all-over inspection and medical operation inside the gastrointest-inal tract of human body.