Mine water inrush is one of the main disasters in coal mines. In recent years, the major accidents in coal mines were all water disasters, causing heavy casualties and property losses. As computer technology has developed, deep learning(Jayapriya and Jacob et al., 2020; Byun and Kim et al., 2021) technology has gradually been applied to mine engineering (Sun and Nieto et al., 2010; Yang and Yue et al., 2018; H. and K., 2020) and water resource engineering(Hrnjica and Bonacci, 2019; Wang and Lin et al., 2019; Wu and Ma et al., 2021). Existing methods have mostly used traditional image recognition, which recognizes water inrush in only a particular scene, but the mine environment is harsh and the image scenes are diverse, so traditional image recognition has difficulty accurately recognizing complex scenes. Compared with traditional image recognition, image recognition algorithms based on deep learning have strong generalization ability and robustness, and they can adapt to image recognition in multiple scenes. However, these applications are based on deep learning with a large number of samples. Small sample sizes result in overfitting problems and low recognition rates. Most importantly, there is little probability of water inrush occurring in mines, so obtaining real samples of water inrush is difficult. To solve this problem, A deep-learning method was used to identify a limited number of water inrush samples using few-shot learning(Liu and Qiu et al., 2022). Few-shot learning refers to classifying new images with a small amount of labeled training data, comparing the predicted images with a small number of images already in the category, and comparing the similarity between them to determine the category of the image.
Among the methods currently in use, Liu et al. (Liu and Li et al., 2021) proposed a coal and coal gangue detection method based on YOLO v4, and Wang (Wang and Wang, 2014) proposed a new method of obtaining coal texture features using a co-occurrence matrix, which was input into the neural network as a feature vector. Zhang et al. (Zhang and Zhang, 2018) summarized the image recognition of coal and rock and pointed out the existing problems. Jing et al. (Li and Yong et al., 2019) proposed a new mine water source discrimination method based on a generative adversarial network using the fluorescence spectrum of water samples. Alfarzaeai et al. (Alfarzaeai and Niu et al., 2020) used a convolutional neural network (CNN) and thermal imaging to identify coal gangue. Lei et al. (Si and Xiong et al., 2020) proposed a coal rock–recognition algorithm based on a deep CNN, which solved the overfitting problem of the CNN and had a good recognition effect on coal rock images. These studies achieved good results in their respective fields, but few scholars have conducted in-depth research on the image recognition of mine water inrush. The main reason is that mine water inrush is extremely contingent, so line storage has very few samples, and large-scale learning is difficult to conduct. Therefore, image recognition based on small samples can well solve the problem of fewer samples.
The original method of few-shot learning uses generative models and data augmentation (A. and A., 2015). This method has also achieved certain results, but overfitting problems, among others, remain. Subsequently, meta-learning (Finn and Abbeel et al., 2017) has proposed a new idea for few-shot learning. Different from the traditional learning model, meta-learning guides learning based on the comparison method. For example, the Siamese neural network proposed by Koch et al. (Koch and Zemel et al., 2015) is a type of meta-learning. Providing an application case, Li et al. (Li and Eigen et al., 2019) proposed a feature-learning module based on the metric-learning algorithm, which specifically extracted "intra-class commonality" and "inter-class uniqueness". The most commonly used matching method in meta-learning is metric learning (Atkeson and Moore et al., 1997)(Atkeson and Moore et al., 1997), which classifies the extracted feature vectors using the distance measurement method. In the metric method, the cosine distance (Vinyals and Blundell et al., 2016) is often used to calculate the similarity of two feature vectors. Because underground conditions are dim, the feature extraction network has difficulty extracting the features of water seepage in the coal wall, and it cannot judge whether it has water inrush. Therefore, in image recognition, focus on the fine-grained classification of images.
Lin et al.(Lin and RoyChowdhury et al., 2015) proposed a bilinear convolutional neural network(Bilinear-CNN), which uses two feature extraction networks and intersects the feature maps in pairs to ensure that the image features are not lost. Considering the small number of mine water inrush samples and the problem of fine-grained image classification, A few-shot learning method was used based on metric classification to classify images and a bilinear neural network to extract feature maps to enhance the recognition rate of the fine-grained images.
This study used the training method of a matching network to obtain the feature vector of the image. then fine-tuned the support and target sets. And explain the fine-tuning effect through experimental comparison. Because all sudden mine water is water flow or water droplets attached to the coal wall, and the coal wall is dark in color and has an uneven surface, recognizing when water is seeping from the surface of the coal wall is difficult. For feature extraction, previous few-shot recognition algorithms have used monolinear neural networks, which are prone to losing many image details. Therefore, this problem was solved by classifying images with such features as fine grained (Gao and Beijbom et al., 2016; Cui and Zhou et al., 2017; Kong and Fowlkes, 2017; Sun and Wang et al., 2018; T. and A. et al., 2018; Wei and Zhang et al., 2018). Furthermore, bilinear neural networks was used for feature extraction during pre-training to enhance the feature channels of the images and recognize the hanging sweat feature of burst mine water. Finally, compared the feature extraction effects of bilinear convolutional neural networks based on resnet8, resnet50 and VGg16 respectively.