仿生复眼系统标定及测量方法研究

The Method for the Calibration and Measurement of Bionic Compound-eye System

为了实现对近景目标物的三维测量,研制了一种小型仿生复眼系统。介绍了该复眼系统的结构及其参数设计原则,并对该系统采用的标定、三维测量等算法进行研究。首先根据复眼成像特点搭建了标定和测量平台,并分别使用张正友的方法、直接线性变换法、Tsai式两步法三种摄像机标定方法对复眼的中心子眼进行标定,通过比较实验结果发现Tsai式标定方法精度更高,更适用于本复眼系统的标定。然后针对边缘子眼光轴与图像传感器不垂直问题,提出了一种新的图像畸变数学模型,有效的提高了边缘子眼的标定精度。最后建立了多子眼三维探测模型,并探索了多子眼成像对复眼相机测量精度的影响,认为三子眼可获得比双子眼更高的精度和稳定性。实验结果表明,在距离复眼相机150?260 mm范围内,该复眼探测系统的三维测量相对误差在2%左右,在满足仪器小型化的同时能基本实现近景三维测量。

In order to realize close-range measurement, a miniaturized bionic compound-eye system was developed and the design principles of the system structure and parameters were introduced. Besides, the calibration and three-dimensional measurement algorithms were investigated. First, the platform for calibration and measurement was built based on imaging characteristics of the compound-eye. Three kinds of camera calibration methods, including Zhang’s method, the direct linear transformation method and Tsai two-step method, were carried out to calibrate the central sub-eye. By comparing the experimental results, it was determined that Tsai two-step method with high precision and accuracy was suitable for the calibration of the compound-eye system presented. Then, to solve the problem that the edge sub-vision axis was not perpendicular to the image sensor, a new distortion model that effectively improved the edge sub-eye calibration accuracy was proposed. Finally, a multiple sub-eye detection model was established, and its impact on the compound-eye camera measurement accuracy were discussed, from which it was determined that three sub-eye condition had better accuracy and stability than the two-eye. Experimental results indicate that the relative error of the compound eye three-dimensional detection system is about 2%when the object distance ranges from 150～260 mm, and this system could achieve the instrument miniaturization and basic close-range measurement.