陈继清　强虎　徐关文　刘旭　莫荣现　 黄仁智

摘  要： 针对园林喷药机器人在绿篱带、花圃周围难以自动导航的问题，该文提出一种基于Hough变换拟合导航线的方法;利用逐段分解的思想，将弯路分解为多个近视直路;使用该文改进的灰度化因子处理分解后的路段图像;考虑到机器人在工作的时候会有农药或水滴影响图像质量，采用中值滤波强化图像;为了避免光照不均匀的影响，采用基于局部统计的可变阈值法二值化灰度图像;为了加快处理速度，每隔10像素行取一个采样行，采用相对白色像素中点的算法求取导航离散点，最后使用Hough变换拟合导航点，提取导航线。实验结果表明，该文提出的提取導航线的方法具有稳定性好、精度高、算法简单的优点。

关键词： 喷药机器人; 导航线提取; Hough变换; 图像预处理; 图像二值化; 导航离散点

中图分类号： TN820.4?34                           文献标识码： A                      文章编号： 1004?373X（2020）20?0183?04

Extraction of Hough transform based navigation line of garden spraying robot

CHEN Jiqing1，2， QIANG Hu1， XU Guanwen1， LIU Xu1， MO Rongxian1， HUANG Renzhi1

（1. College of Mechanical Engineering， Guangxi University， Nanning 530007， China;

2. Guangxi Key Laboratory of Manufacturing System and Advanced Manufacturing Technology， Nanning 530007， China）

Abstract： In allusion to the problem that the garden spraying robot is difficult to navigate automatically around hedgerow and flower nursery， a method of fitting navigation line based on Hough transform is proposed. The curved path is divided into several myopic straight paths by means of the idea of piecewise decomposition， which is processed by using the improved gray scale factor. Considering that there will be pesticides or water droplets affecting the image quality when the robot is working， the median filtering is used to intensify the image. The gray image is binarized by means of the variable threshold method based on local statistics to avoid the influence of uneven illumination. In order to speed up the processing， a sampling line is taken every 10 pixels， the navigation discrete points are calculated by means of the relative white pixel midpoint algorithm， and the navigation points are fitted by the Hough transform to extract the navigation lines. The experimental results show that the proposed method of extracting the navigation line has the advantages of stability， high accuracy and simple algorithm.

Keywords： spraying robot; navigation line extraction; Hough transform; image preprocessing; image binaryzation; navigation discrete point

0  引  言

随着城市的发展，城市生态功能却逐渐下降，严重影响到居民的生活质量，随着酸雨、雾霾等一系列生态事故的发生，让人们意识到了园林绿化的重要性[1];园林绿化在一定程度上可以减弱噪声对人心理的影响，提高人们的幸福感[2?4]。但是园林的维护需要很大的成本，尤其是杂草的防治。

在现代园林建设中，杂草的防治是一项看起来简单而做起来繁杂的工作，杂草的生长对园林植物生长的好坏和美观有着非常重要的影响，如果不能很好的防治杂草生长，可能会引起园林原有自然景观的退化[5?6]。……