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基于改进Faster RCNN的茶叶叶部病害识别
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作者 姜晟 曹亚芃 +3 位作者 刘梓伊 赵帅 张振宇 王卫星 《华中农业大学学报》 CAS CSCD 北大核心 2024年第5期41-50,共10页
针对茶园复杂背景下茶叶叶部病害识别较为困难的问题,提出一种基于改进Faster RCNN算法的茶叶叶部病害识别方法。通过对优化区域建议框的特征提取网络VGG-16、MobileNetV2和ResNet50进行比较,选择识别效果较好的ResNet50作为骨干网络,... 针对茶园复杂背景下茶叶叶部病害识别较为困难的问题,提出一种基于改进Faster RCNN算法的茶叶叶部病害识别方法。通过对优化区域建议框的特征提取网络VGG-16、MobileNetV2和ResNet50进行比较,选择识别效果较好的ResNet50作为骨干网络,增加模型在茶园复杂背景下对茶叶叶部病害特征的提取能力;融入特征金字塔网络(feature pyramid network,FPN)改善小目标漏检问题和病斑的多尺度问题;采用Rank&Sort(RS)Loss函数代替原Faster RCNN中的损失函数,缓解样本分布不均给模型带来的性能影响,进一步提高检测精度。结果显示:改进模型平均精度均值PmA为88.06%,检测速度为19.1帧/s,对藻斑病、白星病、炭疽病、煤烟病识别平均精度分别为75.54%、86.84%、90.42%、99.45%,比Faster RCNN算法分别提高40.98、44.16、13.9和2.43百分点。以上结果表明,基于改进Faster RCNN算法的茶叶叶部病害识别方法能够弱化茶园复杂背景的干扰,准确识别茶园复杂背景下茶叶叶部病害目标。 展开更多
关键词 目标检测 茶叶叶部病害 FPN网络 Rank and Sort loss 区域建议网络
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Adversarial Learning for Distant Supervised Relation Extraction 被引量:7
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作者 Daojian Zeng Yuan Dai +2 位作者 Feng Li R.Simon Sherratt Jin Wang 《Computers, Materials & Continua》 SCIE EI 2018年第4期121-136,共16页
Recently,many researchers have concentrated on using neural networks to learn features for Distant Supervised Relation Extraction(DSRE).These approaches generally use a softmax classifier with cross-entropy loss,which... Recently,many researchers have concentrated on using neural networks to learn features for Distant Supervised Relation Extraction(DSRE).These approaches generally use a softmax classifier with cross-entropy loss,which inevitably brings the noise of artificial class NA into classification process.To address the shortcoming,the classifier with ranking loss is employed to DSRE.Uniformly randomly selecting a relation or heuristically selecting the highest score among all incorrect relations are two common methods for generating a negative class in the ranking loss function.However,the majority of the generated negative class can be easily discriminated from positive class and will contribute little towards the training.Inspired by Generative Adversarial Networks(GANs),we use a neural network as the negative class generator to assist the training of our desired model,which acts as the discriminator in GANs.Through the alternating optimization of generator and discriminator,the generator is learning to produce more and more discriminable negative classes and the discriminator has to become better as well.This framework is independent of the concrete form of generator and discriminator.In this paper,we use a two layers fully-connected neural network as the generator and the Piecewise Convolutional Neural Networks(PCNNs)as the discriminator.Experiment results show that our proposed GAN-based method is effective and performs better than state-of-the-art methods. 展开更多
关键词 Relation extraction generative adversarial networks distant supervision piecewise convolutional neural networks pair-wise ranking loss
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