煤岩识别是极薄煤层综采工作面实现智能化开采的核心技术之一。针对极薄煤层开采时煤岩分界线自然裸露在外的特殊情况，提出了一种基于MRU-Net++网络的极薄煤层煤岩图像识别方法。该网络以U-Net++为基础，通过“剪枝”技术对U-Net++结构进行优化，在U-Net++网络性能损失最小的同时减少其复杂度，以提高运算速度；采用MobileNetV2轻量化网络，构建一个基于MobileNetV2的核心骨干网络，替代U-Net++原有的网络架构，显著降低了模型的参数数量，提高了模型分割效率；同时引入含有通道注意力机制的ResNeSt模块来增强对煤岩图像边缘细节特征的提取能力，提高分割精度。利用液压支架上的防爆摄像仪采集极薄煤层综采工作面煤岩图像，获取具有煤岩分布信息的高清煤岩图像并对图像进行预处理，创建含有2 536个样本的极薄煤层综采面煤岩图像数据集。设置消融试验，验证改进部分对网络性能的影响，并将该模型与经典FCN、U-Net、U-Net++网络模型进行对比，利用自适应学习算法训练各网络模型，选择像素准确度(Pixel Accuracy, P_A)、交并比(Intersection over Union, I_OU)及测试时间等关键指标评估模型分割效果。结果显示，MRU-Net++网络模型的平均像素准确度P_AM和交并比I_OUM分别为97.15%和94.16%，模型占用内存25.71 M，每张图像的平均测试时间28.61 ms，充分证明了该方法在极薄煤层特殊环境下进行煤岩识别任务的可行性与有效性。

Coal rock recognition is one of the core technologies to realize intelligent mining in the integrated mining face of extremely thin coal seam. Aiming at the special situation that the coal-rock boundary is naturally exposed during the mining of extremely thin coal seams, an image recognition method based on MRU-Net++ network was proposed for coal-rock image recognition of extremely thin coal seams. The network is based on U-Net++, and the structure of U-Net++ was optimized by the method of “pruning”, which reduces the complexity of U-Net++ network while minimizing the loss of its performance in order to improve the computing speed. MobileNetV2 lightweight network was used to construct a core backbone network based on MobileNetV2, replacing the original network architecture of U-Net++, which significantly reduces the number of parameters of the model and improves the efficiency of the model segmentation. At the same time, the ResNeSt module, which contains the channel attention mechanism, was introduced to enhance the ability of extracting the detailed features of the edges of the coal and rock images, and to increase the segmentation accuracy. The explosion-proof camera on the hydraulic support was used to collect the coal rock images of the comprehensive mining face in the extremely thin coal seam, and the high-definition coal rock images with coal rock distribution information were acquired and preprocessed to create a coal rock image dataset of the comprehensive mining face of the extremely thin coal seam containing 2 536 samples. The ablation test was set up to verify the effect of the improved part on the network performance. The model was compared with the classical FCN, U-Net, and U-Net++ network models and the network models were trained using adaptive learning algorithms. Key indexes such as Pixel Accuracy (P_A), Intersection over Union (I_OU) and test time were selected to evaluate the model segmentation effect. The results show that the Mean Pixel Ascuracy (P_AM) and Mean Intersection over Union (I_OUM) of the MRU-Net++ network model are 97.15% and 94.16%, respectively, the memory occupied by the model is 25.71 M, and the average test time of each image is 28.61 ms, which fully proves the feasibility and effectiveness of the method for the coal rock recognition task under the special environment of extremely thin coal seam.