基于学生人体检测的无感知课堂考勤方法

针对基于人脸识别的课堂考勤系统漏检和低识别率的问题，采用主、从双摄像机设备，提出一种联合学生人体检测和人脸角度筛选的方法。首先通过Mask R-CNN算法检测主摄像机拍摄图中的学生人体位置；然后控制从摄像机（PTZ相机）依次获取每位学生的高质量放大图像；再通过MTCNN算法和FSA-Net算法从中检测并识别出人脸姿态，筛选出每位学生的正脸图像；最后对筛选出的学生正脸图像使用FaceNet算法提取人脸特征，用于支持向量机（SVM）分类器的训练或识别。实验结果表明，与Tiny-face算法相比，人体检测算法在重叠比（IOU）为0.75时平均精度（AP）值提高了约36%且检测耗时减少了57%；与建立多姿态人脸数据库的方法相比，采用人脸角度筛选的方法使识别率提高了4%；多数情况下整个课堂学生识别的准确率接近100%。所提方法简化了学生注册过程，提高了人脸识别率，为解决人脸漏检问题提供了新的思路。

Non-perception class attendance method based on student body detection

Concerning the missed detection and low recognition rate in the class attendance system based on face recognition, a method that combines student body detection and face angle filtering was proposed by applying the master and slave dual-camera device. First, the bodies of students were detected from the photograph of master camera by the Mask R-CNN algorithm. Then, the slave camera (PTZ (Pan/Tilt/Zoom) camera) was controlled to acquire high-quality magnified image of each student in turn. Next, the face poses were detected and recognized in the magnified images through MTCNN (Multi-Task Convolutional Neural Network) algorithm and FSA(Fine-grained Structure Aggregation)-Net algorithm in order to filter the frontal face image of every student. Finally, the FaceNet algorithm was used to extract the features of the filtered student frontal face images for training or recognition of Support Vector Machine (SVM) classifiers. Experimental results showed that, compared with the Tiny-face algorithm, when the Intersection over Union (IOU) was 0.75, the body detection algorithm had the Average Precision (AP) value increased by about 36% and the detection time reduced by 57%; compared with the method of establishing a multi-pose face database, the method of face angle filtering improved the recognition rate by 4%; and the accuracy of student recognition in the entire classroom was close to 100% in most cases. The proposed method simplifies the student registration process, improves the face recognition rate, and provides new ideas for solving the problem of face missed detection.