基于差分计盒维数及最大熵阈值的裂缝提取  

Road crack extraction based on differential box dimension and maximum entropy threshold

作　　者：刘晟[1] 王卫星[1] 曹霆[1] 杨楠[1] 杨洋[1] 

机构地区：[1]长安大学信息工程学院,陕西西安710064

出　　处：《长安大学学报（自然科学版）》2015年第5期13-21,共9页Journal of Chang’an University(Natural Science Edition)

基　　金：陕西省国际合作重点项目(2013KW03);中央高校基本科研业务费专项资金项目(CHD2013G2241019)

摘　　要：为了解决在公路路面裂缝的识别和检测过程中,边界细节不明显,噪声干扰不易去除,且存在断裂现象等难点问题,提出了一种新的路面裂缝提取方法。首先利用灰度的垂直和水平投影曲线判断裂缝的类型为横向裂缝、纵向裂缝或网状裂缝;继而根据裂缝的走向进行图像的非对称缩小,减少了背景的无用信息,保留了目标特征边缘,同时提高了检测速度;再采用改进分形理论中的差分计盒维数法对灰度图像分割,即通过计算尺度为1时像素点2×2区域的分维数作为裂缝分割的基础;最后提出通过最大熵阈值法确定阈值,并从端点处循环进行8邻域搜索,找到下个端点,进行断点连接,并去除细小孤立分支,准确地提取裂缝。最后与传统方法进行了对比试验。结果表明:对于具有单条或几条裂缝的图像,新方法能令人满意地提取路面裂缝,抗噪性能好,其结果与人工识别的结果较接近。In order to solve the problems of unobvious boundary details, a lot of noise and fractures in the process of highway pavement crack detection and recognition, a new method for extracting pavement cracks was presented. Firstly, according to vertical and horizontal projection curve of the gray value, types of cracks were analyzed to determine whether it is transverse crack, lengthways crack or map crack. Images were reduced asymmetrically based on these types. The analysis speed and detection efficiency were improved significantly. The method not only reduced noise but also preserved edge information. Secondly, according to the fractal characters of crack image, the images were segmented with the improved differential boxcounting algorithm （DBC）. That means the fractal dimension of the image point of 2 × 2 neighbourhood was the basis of the segmentation when the scale was 1. Finally, the maximum entropy threshold method was put forward to determine threshold and search circularly in 8- neighborhood from the endpoint. The next endpoint was found, the breakpoints were connected, and the tiny isolated branches were removed in the crack images. Compared with the traditional methods, this new approach can extract most of the cracks images boundaries. The results are relatively close to the artificial recognition.

关 键 词：道路工程 路面裂缝 图像缩小 分形学 差分计盒维数 最大熵 阈值 

分 类 号：U411[交通运输工程—道路与铁道工程]