摘要
用同心圆做靶面标志,将同心圆靶平行于舵轴固定在舵面上,用单目视觉法实时测出方向舵转动前、后同心圆的位置姿态求转角,取同心圆平行于像面的直径为特征直径。取与特征直径垂直的直径为辅助特征直径,证明了它的像与同心圆透视投影的两个椭圆中心和圆心像点共线,根据共线四点交比不变可求圆心像点。图像处理求出圆心像点位置和两种特征直径的像和它们的原像,可求出靶面的位置姿态和转角。仿真测量结果:测量范围±85°;加标准偏差为2像素的高斯噪声时测角位移的RMS误差小于0.04°。该方法抗噪声能力强;能修正靶面与转轴不平行导致的测量误差,使测量设备安装调节简单。可在停机场实时标定飞机方向舵、升降舵等的角位移传感器。
The concentric circle is taken as target mark. The target parallel to the rudder shaft is fixed on the rudder face Based on monocular vision, a method for measuring object position and orientation is designed to obtain its angular displacement. Take the diameter parallel to the imaging-plane as a characteristic diameter, and take the diameter perpendicular to the characteristic diameter as an auxiliary characteristic diameter. It is proved that the auxiliary characteristic diameter＇s image and two elliptic centers and the projected center are collinear. Based on the invariance of cross ratio, the projected center can be found. Through digital image processing, these characteristic diameter images and their preimages can be obtained. Thus, the relative position and orientation of the concentric circle and its angular displacement can be derived. Simulating test results： measuring range±85° and RMS error less than 0.04° when Gaussian noise level is 2 pixels, Proposed method has strong ability to resist noise. Measurement errors caused by the target-plane deviating from the rudder-axis direction may be corrected. By this method, the angular displacements of rudder can be calibrated.
出处
《光电工程》
CAS
CSCD
北大核心
2013年第10期22-27,共6页
Opto-Electronic Engineering
关键词
光学测量
角位移
单目视觉
同心圆
特征直径
交比
optical measurement
angular displacement
monocular vision
concentric circle
characteristic diameter
cross ratio
