Sound Field Visualization Research Based On Polarization Parametric Imaging Method

Ultrasound has been widely used in product defect detection,biomedical imaging,medical treatment and other fields due to its advantages such as high penetration,good directivity and safety.The fast,non-contact,highly sensitive optical imaging method detects photoacoustic signals,which can be used to deeply image living biological tissues and improve the speed of sound field detection and image contrast.Optical method is used to visualize the sound field distribution of photoacoustic signals,which can quickly measure the sound pressure,the frequency of sound waves,and the characteristics of sound sources.The depth reconstruction results of living biological tissues obtained through image reconstruction algorithms are of great significance in biomedical research.In this paper,the polarization parametric imaging method is used to detect the sound field distribution of ultrasonic waves.Utilizing the birefringence effect caused by the propagation of ultrasonic waves in the medium,the liquid crystal polarization modulation imaging method and the polarization camera imaging method are used to calculate the change of the polarization parameters of the transmitted light to obtain the sound field distribution information of the ultrasonic waves.Liquid crystal polarization modulation imaging experiments and polarization camera imaging experiments were designed.The ultrasonic visualization results were successfully obtained.Compared with the dynamic photoelastic experiment,the results prove the effectiveness of the polarization parametric imaging method.The liquid crystal polarization modulation imaging method overcomes the jitter error caused by rotating the polarizing plate,which has a fast polarization modulation speed,high imaging contrast.The polarization parameter azimuthal angle ? is sensitive to ultrasonic waves.In order to further improve the imaging speed and image contrast,the Stokes parameter,phase difference ?,and orientational angle ? can be calculated by acquiring an image of a polarization camera through the polarization parameter imaging method.The imaging speed is fast and the image contrast is further improved,especially the polarization parameter phase difference ? and the orientational angle ? are very sensitive to ultrasonic sound pressure,which provides a quantitative evaluation imaging method for sound field detection.Polarization parameter imaging technique has the advantages of non-contact measurement,wide bandwidth,large field of view,and fast imaging speed.The polarization parameter phase difference ? and orientational angle ? are very sensitive to ultrasonic sound pressure,which is expected to be used in photoacoustic imaging systems,non-destructive testing of products,Stress analysis and other fields.