Abstract: To address the issues occurred in the current sand patch method for measuring mean texture depth (MTD), a novel MTD estimation approach based on 3D point cloud data was proposed. Initially, 300 sets of cement concrete road surface samples with varying degrees of wear were scanned to collect point cloud data, which were then processed through horizontal correction, outlier removal, and Gaussian filtering. Subsequently, the height of the sand patch top surface was determined by using the second derivative of the cumulative percentage of point cloud heights, and subarea division and polynomial surface fitting techniques were employed to generate the sand patch top surface. Finally, the MTD was estimated by calculating the envelope volume between the sand patch top surface and the road surface through the Monte Carlo method. The results indicate that the random sample consensus algorithm （RANSAC）can effectively perform horizontal correction on cement concrete pavement. The combination of outlier removal with a threshold of 3σ and Gaussian filtering with a kernel standard deviation σ=1 and a search radius r=2 mm can accurately remove outliers in the point cloud data while preserving crucial texture details of the road surface. The estimation results for cement concrete road surfaces with different levels of wear exhibit strong correlations with the measured values, with R2 values of 0.957 2, 0.907 8, and 0.919 1, respectively. The overall estimation accuracy is high, and the relative error (-8.06% to 4.75%) is significantly lower than that of existing methods.

Key words: road engineering; mean texture depth (MTD); Monte Carlo method; cement concrete pavement; horizontal correction

摘要： 针对现有铺砂法测量平均纹理深度（MTD）存在的问题，提出了一种基于三维点云数据的MTD估计方法。首先，通过扫描300组不同磨损程度的水泥混凝土路面样本，获取点云数据，并进行水平校正、离群点剔除和高斯滤波处理；然后，利用点云高度累积百分比二阶导数确定铺砂顶面高度，并采用子区域划分和多项式曲面拟合技术生成铺砂顶面；最终，通过蒙特卡罗法计算铺砂顶面与路面之间的包络体积，估算MTD。结果表明：随机采样一致性（RANSAC）算法能够有效地对水泥混凝土路面进行水平校正，经过阈值为3σ的离群点剔除和高斯核标准差σ=1、搜索半径r=2 mm的高斯滤波，能够较精准地去除点云数据中的离群点，同时保留路面的重要纹理细节；不同磨损程度的水泥混凝土路面估计结果与实测值R2分别为0.957 2、 0.907 8、 0.919 1，呈现强相关性，整体估计精度高，相对误差（-8.06%~4.75%）显著低于现有方法。

关键词: 道路工程；平均纹理深度；蒙特卡罗法；水泥混凝土路面；水平校正