| Face alignment,as known as face landmark detection,is the process of locating important feature points in areas such as mouth,nose,eyes,and contours in a face image.Face alignment techniques are crucial for tasks such as face recognition,expression recognition,and 3D face reconstruction.However,traditional landmark detection algorithms are often limited,and the model is limited in flexibility to adapt to landmarks of various shapes and locations.With the development of computer vision and deep learning,face landmark detection has become a field of great concern.Research has been extended from frontal face images in a certain environment to face images collected under unconstrained conditions,including factors such as pose,illumination,occlusion,and expression.The popular deep learning models,whether based on heat map prediction or coordinate prediction,are stacked by complex network structures,which are difficult to deploy on devices with limited computing resources.This paper will further study and solve the problem of improving the accuracy of face alignment as much as possible in the case of limited computing resources,and strike a balance between accuracy and inference speed,so as to promote the advancement of face landmark detecting technology.This paper studies a lightweight face alignment algorithm based on multi-scale perception,aiming to improve the inference speed and accuracy of face alignment on edge devices.This paper optimizes the network structure,uses depthwise separable convolution to reduce the size of the model,and uses a multi-scale perception strategy to obtain comprehensive feature information,thereby improving the alignment effect and robustness of the algorithm.The parameters of the model finally proposed in this paper are 6.47 M,and the number of floating-point operations per second is 4.48 G,which is only half of the comparison model,and thanks to the multi-scale perception module,the accuracy is also comparable to the comparison model.Furthermore,this paper proposes an optimization algorithm for face alignment based on prior knowledge.The algorithm adopts the method of predicting the offset between the real landmarks and the prior landmarks,and transforms the detection task into a regression problem,avoiding the problem of designing complex neural networks and feature extraction methods in traditional algorithms.In order to solve the problem that the landmarks of the face with a large head deflection that are difficult to fit,this paper adopts a redesigned weighted loss function and an online hard example mining strategy.The purpose is to adjust the sample weight according to the actual situation and reduce the head.deflection effect.This paper also adopts a method of building an auxiliary classifier to recognize faces of different poses and shapes,which benefit to address the complexity of the training process and the need to normalize faces.These innovative designs and strategies effectively improve the accuracy and stability of the algorithm,and the normalization error in difficult samples in challenging datasets like occlusion,and blurring face images is reduced by about 2% compared with popular models.In order to verify the effectiveness of the algorithm,this paper evaluates it on three challenging datasets: WFLW,300 W and COFW.The experimental results show that the algorithm in this paper is comparable to some SOTA models in terms of accuracy,but the number of parameters and the number of floating-point operations per second of the model are much smaller than the popular models.It shows that the algorithm proposed in this paper has good performance,which is suitable for practical application.This algorithm can significantly improve the computer’s recognition speed and accuracy,thereby providing users with a better user experience.It will play an important role in real-time face recognition,intelligent transportation,virtual reality and other fields,bringing great commercial value.Various fields bring more opportunities and potential.The algorithms proposed in this paper not only bring new breakthroughs in the field of computer vision and machine learning,but also promote the further development of technology,making this paper more capable of realizing various future visions and possibilities. |