A Micro-Expression Apex Frame Spotting Method Based on Optical-Flow-Dual-Input Network
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摘要: 微表情顶点帧蕴含着丰富的微表情信息,为了准确地检测出微表情顶点帧,本文提出了一种基于光流特征的神经网络分类,并利用先验知识规则进行取舍的检测方法. 该方法针对固定滑窗大小内的图像进行光流信息提取,利用双输入特征提取网络对x, y方向的光流信息进行时空特征提取,并进行分类,经根据微表情先验知识所设计的取舍规则后处理后,改善了检测准确度. 实验结果表明,在数据集CASMEⅡ上测试,顶点定位率(apex spotting rate,ASR)指标达到了0.945,F1-score指标达到了0.925.Abstract: Micro-expression apex frame contains abundant micro-expression information. In order to spot the apex frame accurately, a neural network classification was proposed based on optical flow characteristics. Taking prior knowledge as rules, a detection method was designed to realize micro-expression apex frame spotting. Firstly, optical flow information was extracted from the image in a fixed size sliding window. And then, the spatial and temporal features of optical flow information in x and y directions was extracted and classified based on dual input network. Finally, according to the trade-off rules based on prior knowledge of micro expression, a post-processing was carried out to improve the detection accuracy. The experimental results on data set CASMEⅡtesting show that the apex spotting rate (ASR) and F1-score can reach up to 0.945 and 0.925 respectively.
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表 1 网络结构检测对比结果
Table 1. Evaluation of network structure
方法 检测结果数量 TP FP FN 单输入结构 100.32 51.97 48.32 0.12 双输入结构 80.82 41.35 40.47 0.05 表 2 后处理方法检测对比结果
Table 2. Evaluation of post-processing
方法 检测结果数量 TP FP FN 后处理模块 80.82 41.350 40.470 0.05 有后处理模块 0.95 0.875 0.074 0.05 表 3 MAE、ASR指标评估
Table 3. MAE and ASR evaluation
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