Research On Compressed Sensing Based Ultrasound Correlation Imaging

In conventional ultrasound imaging systems,the resolution of an imaging system is related to the size of the aperture,the larger the aperture,the higher the resolution.However,the size of the aperture cannot be increased indefinitely to realistic conditions,as this would not only place higher demands on the manufacturing cost,but also limits the application scenarios for the aperture.In this case,we need to find a suitable ultrasound imaging method that can both improve the resolution and the high signalto-noise ratio.This thesis is inspired by the compressed-sensing-based lensless ghost imaging method,and we would like to introduce the correlation imaging method into the field of ultrasound imaging.From this point of view,an ultrasound correlation imaging method based on compressed sensing is proposed.This method could,to a certain extent,overcome the diffraction limit of the imaging system,improve the imaging quality,and provide useful information for subsequent studies.In this thesis,we investigated the basic theory of ultrasound correlation imaging firstly,and proposed an ultrasound correlation imaging model by analyzing the architecture of lensless ghost imaging.And by incorporating with the theory of compressed sensing,we proposed a compressed-sensing-based ultrasound correlation imaging method,which is capable of achieving the super-resolution imaging by deconvolution.The proofs-of-principle experiments have demonstrated the effectiveness of this imaging method,both in achieving the application of ghost imaging in the mechanical wave field but also another useful option to the ultrasound imaging system.Secondly,the impacts of the different parameters during the emission for the quality of ultrasound correlation image have been analyzed.According to the analysis,it was found that regardless of the signal with which it was emitted,the ultrasound correlation imaging resolution was only correlated with the synthetic wavefront at the target scene.In addition,the arrangement of the arrays and the size of the target scene will also have an impact on the quality of the ultrasound correlation imaging,and the unfavorable parameters will cause excessive smoothing of the ultrasound scattering pattern,which is not conducive to the correlation imaging.Finally,from the point of view of applications,the idea of random modulation in the ultrasound correlation imaging method is applied to the ultrasound array imaging method,which could improve the imaging resolution while improving the imaging frame rate,and it is demonstrated through numerical simulation and experiments that the random modulation method has the ability of super resolution imaging.