基于图像处理技术的低噪声微表处纹理与噪声评价

分析了路面微表处噪声产生机理，设计了5种低噪声微表处，并与普通微表处进行对比，测试了不同微表处的构造深度及其噪声值；基于数字图像处理技术构建微表处纹理三维模型，挖掘相关纹理参数以评价不同微表处的构造和噪声特性；提出凸峰分布概率、凸峰面积占比2种路表纹理参数，并分析了该参数与室内噪声的相关性。分析结果表明：与普通中值级配微表处相比，低噪声级配微表处可降低噪声约3.1 dB；橡胶粉通过提高微表处的弹性和吸声特性降低表面构造和摆值，且掺入中值和低噪声级配微表处可分别降低噪声2.0与6.3 dB；水性环氧树脂通过改善微表处施工和易性，减少路面宏观纹理，且掺入中值级配的微表处能实现与低噪声级配微表处相似的降噪效果；基于表面纹理三维模型计算的像素差平均值与微表处的实际构造深度呈显著的线性关系，相关系数为0.94；中值级配和低噪声微表处的凸峰高度分布分别表现为一次函数和正态函数，级配的调整可显著减小低高度凸峰的分布率，且低高度的凸峰数量增加可丰富细观纹理，进而得出凸峰分布概率能够量化微表处纹理的分布特性；凸峰高度0.25 mm是各种微表处凸峰高度分布曲线的拐点，与所有凸峰高度的面积占比相比，凸峰高度大于0.25 mm的面积占比与微表处的噪声具有显著的线性相关性，相关系数为0.98。

Evaluation of texture and noise of low-noise micro-surface based on image processing technology

The mechanism of noise generation at pavement micro-surface was analyzed, five low-noise micro-surfaces were designed and compared with common micro-surfaces, and the texture depths and noises of different micro-surfaces were tested. A three-dimensional texture model of micro-surfaces was constructed based on the digital image processing technology, and the relevant texture parameters were excavated to evaluate the textures and noise characteristics of different micro-surfaces. Two pavement surface texture parameters, namely the probability of convex peak distribution and the proportion of convex peak area, were proposed, and the correlations between the parameters and indoor noise were analyzed. Analysis results show that compared with the micro-surface with common medium gradation, the micro-surface with low-noise gradation can reduce the noise by 3.1 dB approximately. Rubber powder in micro-surface can reduce the surface structure and pendulum value by improving the elasticity and sound absorption characteristics of micro-surface, and the noise can be reduced by 2.0 and 6.3 dB by mixing into the medium gradation and low-noise gradation, respectively. Water-based epoxy resin in micro-surface can reduce the macroscopic texture of pavement by improving the workability during construction, and the noise can be reduced by mixing into the medium gradation. The noise reduction effect is similar to that of micro-surface with low-noise gradation. The average pixel difference calculated based on the three-dimensional texture model has a significant linear relationship with the actual texture depth of micro-surface, with a correlation coefficient of 0.94. The distributions of convex peak heights of micro-surfaces with the medium gradation and low-noise gradation exhibit a linear function and a normal function, respectively, and the adjustment of the gradation can significantly reduce the distribution of the lower convex peak height. Additionally, an increase in the number of low convex peaks can enrich the texture of micro-surface, and thus the probability of convex peak distribution can quantify the texture distribution characteristics of micro-surface. The convex peak height of 0.25 mm is the inflection point of the probability of convex peak height distribution curve, and the percentage of the area with a convex peak height greater than 0.25 mm has a significant linear correlation with the noise on micro-surface compared with the full range of convex peak height, and the correlation coefficient is 0.98.