基于改进ResNet50模型的大宗淡水鱼种类识别方法

    Freshwater fish species identification method based on improved ResNet50 model

    • 摘要: 针对传统鱼类识别方法存在特征提取复杂、算法可移植性差等不足,该研究提出了一种基于改进ResNet50模型的淡水鱼种类识别方法。研究以鳙鱼、鳊鱼、鲤鱼、鲫鱼、草鱼、白鲢6种大宗淡水鱼为对象,通过搭建淡水鱼图像采集系统获取具有单一背景的淡水鱼图像,同时通过互联网搜索具有干扰背景的淡水鱼图像,共同构建淡水鱼图像数据集;再对淡水鱼图像进行预处理,以增加样本多样性;构建改进ResNet50模型,增加全连接层Fc1以及Dropout,引入迁移学习机制训练模型,同时选择CELU作为激活函数提高神经网络表达能力,通过Adam优化算法更新梯度,并嵌入余弦退火方法衰减学习率。为验证改进ResNet50模型的准确率等性能,对6种淡水鱼进行种类识别,结果表明:在单次验证方法下,选用包含单一背景图像和干扰背景图像构成的淡水鱼图像数据集训练模型,识别准确率为96.94%,比经典模型提高1.22%,单张淡水鱼图像样本的平均检测时间为0.234 5 s;在四折交叉验证下,选用具有单一背景的图像数据集,模型的识别准确率为100%,选用包含单一背景图像和干扰背景图像的淡水鱼图像数据集,模型的识别准确率为96.20%,说明模型具有较好的泛化性能和鲁棒性。针对混淆矩阵的可视化结果表明:改进的ResNet50模型具有通用的结构和训练方式,对不同背景下的淡水鱼进行种类识别具有较高的准确率,可为淡水鱼种类识别提供技术借鉴。

       

      Abstract: Abstract: Species identification of freshwater fish has a wide range of applications in most fields, such as breeding, fishing, and processing. However, most traditional algorithms of fish identification cannot meet the ever-increasingly high requirements in recent years, such as simple feature extraction, high accuracy, and portability. In this study, a new identification algorithm was proposed for the freshwater fish species using an improved ResNet50 model. Six types of freshwater fish were taken as the research objects, including the bighead, bream, carp, crucian, grass carp, and silver carp. An image acquisition system was established for the freshwater fish images with a single background. As such, an image dataset of freshwater fish was constructed to joint those images with interference background on the Internet. A Pytorch framework was then selected to perform image preprocessing of freshwater fish for the sample diversity. An improved ResNet50 model was thus built to identify the freshwater fish species. Firstly, the fully connected layer Fc1 and Dropout were added, while the migration learning was introduced to train the model. Secondly, CELU was selected as the activation function to improve the expression of the neural network. Finally, Adam optimization was used to update the gradient. A cosine annealing was also embedded to attenuate the learning rate. In addition, the hyperparameters of the model were optimized in the multiple model training. Correspondingly, six kinds of freshwater fish were identified to verify the accuracy and performance of the improved ResNet50 model. A single validation test under a four-fold cross-validation model was carried out to train and evaluate the model. The confusion matrix was used to visualize the recognition of each type of fish. The results showed that: the image dataset of freshwater fish consisting of a single and interference background images was selected to train the model under the single validation, where the accuracy rate was 96.94%, 1.22% higher than before. The average detection time was 0.2345s for a single freshwater fish image. The accuracy rate of the model was 100% under the four-fold cross-validation, when the dataset of the freshwater fish image was selected with a single background. By contrast, the accuracy rate of the model was 96.20%, when the dataset of freshwater fish image consisted of a single and interference background, indicating an excellent general performance and robustness. The accuracy, recall and F1 score of each type of freshwater fish were relatively high visualized to the confusion matrix, when the model was trained on the freshwater fish image and a single background dataset, indicating the superior performance of the model. The improved ResNet50 model presented a general structure and training, while a high accuracy rate under different backgrounds. The finding can provide a sound technical reference for the identification of freshwater fish species in intelligent aquaculture.

       

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