基于根茬检测的秋后残膜回收导航路径提取方法

Method of extraction of navigation path of post-autumn residual film recovery based on stubble detection

针对秋后残膜回收作业视觉导航中的路径规划问题,提出一种作业路径提取方法。提取根茬、残膜和行间茎秆碎叶三类图片的颜色空间特征和纹理特征,按8∶2构成训练集和测试集;以检测根茬为目标,搭建随机森林模型对样本图片进行分类,通过特征重要性和相关性对特征进行降维,使用网格搜索确定随机森林模型的最优模型参数;基于根茬主干保持的直立特点,把检测到的每一个根茬上下顶点作为特征点,通过最小二乘法对所有特征点进行拟合即为作业导航线。试验结果表明,通过特征选择将30维特征降到16维,单幅图像处理时间从0.24 s降到0.16 s。在模型最优参数下,测试集准确率为92.5%。选取450幅10×20像素图片进行分类测试,准确率为91.8%,根茬检测准确率(敏感性)为90.7%。选择200幅ROI区域大小为100×200像素的田间作业图片进行导航线拟合试验,其包括不同天气、不同俯角以及非正常驾驶图片,成功拟合出171幅图像。该根茬检测方法具有较高的稳定性和准确性,可为不同作物根茬检测以及路径提取提供参考。

In view of the path planning problem in the visual navigation of the residual film recovery operation after the autumn,a method of path extraction for residual film recovery operation is proposed.The color space and texture features of the three types of images of stubble,residual film and inter-row noises were extracted to constitute a training set and test set with ratio of 8:2.With the goal of detected root,a Random Forest(RF)model is built to classify the sample images.The feature dimensions are reduced by the feature importance and correlation,the optimal model parameters of the RF model are determined by grid search.Based on the upright characteristics of the stubble,the upper and lower vertices of each stubble are detected as the feature points.All the feature points are fitted by the least square method as the navigation line.The experimental results show that the 30 feature dimensions are reduced to 16 feature dimensions by feature selection,and the processing time of a single image is reduced from 0.24 seconds to 0.16 seconds.Under the optimal parameters of the model,the accuracy of the test set is 92.5%.The classification test was selected for 450 images of 10×20 pixels,the accuracy rate is 91.8%,the accuracy rate(sensitivity rate)of stubble detection is 90.7%.200 field operation images with ROI area size of 100×200 pixels were selected for the navigation line fitting experiment,which included different weather,different depression angles and abnormal driving images,171 images were successfully fitted.The stubble detection method has high stability and accuracy,and can provide reference for root crop detection and path extraction of different crops.