Department of Information and Communication Engineering, Chaoyang University of Technology, Taichung 413310, Taiwan.
Department of Information Technology, Meiho University, Pingtung 912009, Taiwan.
Sensors (Basel). 2020 Apr 29;20(9):2537. doi: 10.3390/s20092537.
One of the common methods for measuring distance is to use a camera and image processing algorithm, such as an eye and brain. Mechanical stereo vision uses two cameras to shoot the same object and analyzes the disparity of the stereo vision. One of the most robust methods to calculate disparity is the well-known census transform, which has the problem of conversion window selection. In this paper, three methods are proposed to improve the performance of the census transform. The first one uses a low-pass band of the wavelet to reduce the computation loading and a high-pass band of the wavelet to modify the disparity. The main idea of the second method is the adaptive size selection of the conversion window by edge information. The third proposed method is to apply the adaptive window size to the previous sparse census transform. In the experiments, two indexes, percentage of bad matching pixels (PoBMP) and root mean squared (RMS), are used to evaluate the performance with the known ground truth data. According to the results, the computation required can be reduced by the multiresolution feature of the wavelet transform. The accuracy is also improved with the modified disparity processing. Compared with previous methods, the number of operation points is reduced by the proposed adaptive window size method.
一种常见的测量距离的方法是使用相机和图像处理算法，例如眼睛和大脑。机械立体视觉使用两个相机拍摄相同的物体，并分析立体视觉的视差。计算视差最稳健的方法之一是著名的普查变换，它存在转换窗口选择的问题。在本文中，提出了三种方法来改进普查变换的性能。第一种方法使用小波的低通带来减少计算负载，并使用小波的高通带来修改视差。第二种方法的主要思想是通过边缘信息自适应选择转换窗口的大小。第三种提出的方法是将自适应窗口大小应用于先前的稀疏普查变换。在实验中，使用两个指标，即坏匹配像素的百分比 (PoBMP) 和均方根 (RMS)，来评估具有已知地面真实数据的性能。根据结果，小波变换的多分辨率特征可以减少所需的计算量。通过修改视差处理也可以提高准确性。与先前的方法相比，所提出的自适应窗口大小方法减少了操作点数。
