Real-time endoscopic image orientation correction system using an accelerometer and gyrosensor

The discrepancy between spatial orientations of an endoscopic image and a physician’s working environment can make it difficult to interpret endoscopic images. In this study, we developed and evaluated a device that corrects the endoscopic image orientation using an accelerometer and gyrosensor. The acceleration of gravity and angular velocity were retrieved from the accelerometer and gyrosensor attached to the handle of the endoscope. The rotational angle of the endoscope handle was calculated using a Kalman filter with transmission delay compensation. Technical evaluation of the orientation correction system was performed using a camera by comparing the optical rotational angle from the captured image with the rotational angle calculated from the sensor outputs. For the clinical utility test, fifteen anesthesiology residents performed a video endoscopic examination of an airway model with and without using the orientation correction system. The participants reported numbers written on papers placed at the left main, right main, and right upper bronchi of the airway model. The correctness and the total time it took participants to report the numbers were recorded. During the technical evaluation, errors in the calculated rotational angle were less than 5 degrees. In the clinical utility test, there was a significant time reduction when using the orientation correction system compared with not using the system (median, 52 vs. 76 seconds; P = .012). In this study, we developed a real-time endoscopic image orientation correction system, which significantly improved physician performance during a video endoscopic exam.内镜图像与医师操作场景的空间方位存在偏差，会大幅增加内镜图像的解读难度。本研究开发并评估了一款借助加速度计（accelerometer）与陀螺仪传感器（gyrosensor）实现内镜图像方位校正的装置：从安装于内镜手柄的加速度计与陀螺仪传感器中提取重力加速度与角速度数据，再通过带传输延迟补偿的卡尔曼滤波器（Kalman filter）计算内镜手柄的旋转角度。本研究通过相机开展方位校正系统的技术性能评估，将采集图像得到的光学旋转角度与传感器输出计算得到的旋转角度进行比对。临床实用性测试阶段，15名麻醉科住院医师分别在启用与未启用方位校正系统的情况下，对气道模型开展视频内镜检查；受试者需报告放置于气道模型左主支气管、右主支气管及右肺上支气管处纸片上的数字，研究记录了受试者报告数字的正确率与总耗时。技术评估结果显示，计算得到的旋转角度误差小于5度。临床实用性测试结果表明，启用方位校正系统时，受试者的检查耗时较未启用时显著缩短（中位时长：52秒 vs 76秒；P=0.012）。本研究开发的实时内镜图像方位校正系统，可显著提升医师在视频内镜检查中的操作表现。