Medical Ultrasonic Imaging Research Based On Compressed Sensing

Ultrasonic imaging has been used widely in medical diagnosis,industrial detection,ocean underwater exploration and other fields because of its damage-free,low-cost and real time.With the development of the technology of medical ultrasonic imaging,the needs of high resolution of ultrasonic imaging inevitably causes the increase of ultrasonic data,which raises a higher requirement to the data storage capability and the transducer array element number of medical ultrasonic imaging system.However,the resolution of traditional ultrasonic imaging is limited by transducer array aperture.The thesis applies the Compressive Sensing theory in medical ultrasonic imaging,which can solve the problems better.Firstly,the thesis introduces the rationale of the Compressive Sensing theory,and does deeper analysis of three aspects of the theory:sparse transform of signals,the design of the measurement matrix and signal reconstruction.Then,using it as the basis,the thesis does the following researches directing at the issues of huge amount of data and large transducer array element number resulted from high quality of medical ultrasonic imaging.Aiming at the issue of large data in the medical ultrasonic imaging system,this thesis analyzes the analog information converter structure of random modulating and modulated wideband converter type,which are designed by the theory of Compressive sensing sampling.According to the deficiency of the two structures and characteristics of ultrasonic echo signal in time domain,the thesis builds an ultrasonic imaging model that is based on the analog information converter filter.The experiment verifies that the model can reduce the data volume of the echo signal of ultrasonic imaging system and combining with phased array technology,it can detect the target point correctly.Aiming at the issue of large transducer array element number,the thesis applies the block sparse method which is based on the space of the wavelet domain in ultrasonic imaging by utilizing the specialties of various array elements of ultrasonic imaging system,and designs three kinds of different scanning methods to have sparse sampling analysis according to the characteristics of ultrasonic phased array scanning sampling.Under the condition of undistorted imaging quality,the experiment testifies that comparing with the traditional methods of imaging,the method can dramatically reduce the total data and the number of data received by linear array transducer that imaging needs.In addition,comparing with the spatial frequency domain sparse algorithm,the method improves the effects of ultrasonic imaging.