Research On Facial Expression Deformation Based On High Precision Digital Image Correlation Method

At present,the relevant research about facial expression is gradually applied to the national security,judicial system,clinical medicine and other fields,but its research is mostly qualitative analysis based on the database.In this paper,the three-dimensional digital image correlation method is used to study the facial expression.Based on the advantages of high accuracy and high adaptability,quantitative analyses are conducted on the facial expressions.It lays foundation for revealing the mechanical behavior of human face and the formation mechanism of facial expressions.In this paper,the theoretical model of error calculation on digital image correlation method is established.Based on the study of different speckle patterns,the objective criterion of the speckle pattern quality is proposed,which is expressed as the optimal gray gradient interval.And the evaluation criterion is verified by numerical simulation and real experiment.Meanwhile,this paper chooses the correlation function that different from others to images matching according to the specific features of the facial muscle measurement.The measurement accuracy of the experimental method is improved with direct current component of the signal.The rigid body displacement caused by the movement of the head is eliminated through the method of coordinate transformation.On this basis,precise calculations and quantitative analyses of the deformation of the muscles in the standard expression and micro expression state are performed.The subject was asked to recall autobiographical memory to induce the basic emotion and then to imitate the specific expression in the standard expression experiment.And the expression inhibition method was used to induce the micro expression.In this paper,we study the behavior of facial expressions about four kinds of specific emotions: joy,anger,sadness and fear.The three-dimensional displacement field is obtained through the whole field calculation and the local calculation.Full field analyses can determine the overall movement of facial muscles and the local analyses of the key parts can carry out a more detailed study.The results show that the movement law of facial micro expression state is basically the same as the normal state except for the displacement amplitude.In this paper,the measurement results of facial expression deformation are basically consistent with the actual situation and conventional cognition.But the difference is that we have made the facial muscle movement laws of these facial expressions from the previous perceptual cognition to the level of accurate calculation and quantitative analysis.