多投影仪自由立体显示系统中的特征点检测及几何校正

Feature-Point Detection and Geometry Calibration for an Autostereoscopic Tiled Display System Using Multiple Projectors

几何校正是多投影仪自由立体显示系统实现无缝拼接显示的关键,而特征点检测是多投影仪组合显示进行几何校正的基础.自由立体显示系统中三维立体显示屏幕的各向异性反射特性使得基于亮度阈值分割的特征点检测方法效果不佳,为此,我们提出了基于轮廓检测的特征点检测方法:采用基于Hough变换的圆检测方法检测特征点的位置,以特征点集的凸包为基准插入及补充漏检的特征点,然后使用两次最小二乘直线拟合方法矫正误差.最后,利用特征点网格,实现了自由立体显示系统的几何校正.实验证明,我们的特征点检测方法鲁棒性好,精度较高,自动地实现了投影显示图像的高精度几何校正.

Geometry calibration is a key step to the seamless display of an autostereoscopic tiled display system using multiple projectors,but the robust detection of feature points is more important because the geometry calibration is based on the feature-point detection.Due to the anisotropic refection characteristics of lens sheets for an autostereoscopic display screen,it is very difficult to find a threshold for the threshold-based method to segment those feature images well.In this paper,we propose a robust feature-point detection method for the autostereoscopic tiled display system using multiple projectors.It first detects feature points with the circle detection method based on Hough transform,then,the convex hull of the feature points is computed;undetected feature points are added into the feature-point mesh,and the coordinates of the feature points are updated twice by the linear least square fitting to minimize the errors;and last,based on the feature-point mesh,the geometry calibration is performed for the autostereoscopic tiled display system using multiple projectors.The experimental results show that our feature-point detection approach is robust and precise enough for the geometry calibration.