基于拟合误差消除的探地雷达图像鲁棒双曲线识别模型
A Robust Hyperbola Recognition Model with Fitting-Errors-Based Eliminating in GPR B-scan Image
-
摘要: 作为一种无损探测工具,探地雷达已广泛应用于各种场景,但从探地雷达B扫描图像中自动提取信息仍然具有挑战性。本文提出了一种从探地雷达B扫描图像中自动识别和拟合双曲线的鲁棒集成模型。首先,实现了由均值对消、基于梯度的自适应阈值算法和开闭操作组成的图像预处理方法,其中,均值对消抑制杂波和噪声,基于梯度的自适应阈值算法可以将B扫描图像转换为二值图像,然后通过开闭操作去除离散的噪声点;接下来,通过下开口扫描聚类算法识别具有向下开口的点集;之后,利用基于代数距离的双曲线拟合算法对这些点集进行直接拟合;最后,根据这些点集的拟合结果,基于拟合误差的剔除方法去除不具有完全双曲特征的下开口点集,从而实现B扫描图像中所有双曲点集的识别和拟合。由上述方法组成的集成模型能够自动、稳健地从探地雷达B扫描图像中提取信息。在合成数据集和实测数据集上的实验表明了所提出模型方法的有效性。Abstract: As a nondestructive tool, ground-penetrating radar (GPR) has been widely used for the investigation of the subsurface, but it is challenging to automatically extract information from GPR B-scan images. In this paper, a robust integrated model for automatically recognizing and fitting the hyperbolae from GPR B-scan images is proposed, which can eliminate non-hyperbolic clusters. Firstly, the preprocessing method which consists of the mean subtraction operation, the adaptive thresholding algorithm based on gradient, and the opening and closing operations is implemented. The mean subtraction operation is utilized to suppress clutter and noise. And the adaptive thresholding algorithm based on gradient could transform the B-scan image to the binary image. Then the opening and closing operations remove discrete noise points. Next, point clusters with downward-opening are identified by open-scan-clustering algorithm (OSCA). After that, these point clusters are directly fitted by hyperbola fitting algorithm based on algebraic distance. Finally, based on the fitting results of these point clusters, the fitting-errors-based eliminating (FEE) method removes downward-opening point clusters without complete hyperbolic feature, thus all hyperbolic point clusters in the B-scan image could be recognized and fitted. This integrated model consisting of methods above can automatically and robustly extract information from GPR B-scan images. The experiments on synthetic and real datasets indicate the effectiveness of the proposed integrated model.