Research On Ultrasonic Tomography Reconstruction Method Based On Back Propagation Algorithm

This paper introduces the mathematical basis of the tomography imaging, the principle of ultrasonic tomography and the structure of the transmission type ultrasound imaging system. In order to optimize the signal acquisition process, the triangular linear array of ultrasonic probe is designed.The projection data are reconstructed by the filtered back projection algorithm.Parallel beam, fan beam and triangle line array filter back projection algorithm reconstruction formula were derived, while the realization steps of the algorithm are given. Through the theoretical calculation, this paper analyze the effect of probe number and the projection angle of imaging quality. The related iterative reconstruction algorithm of ultrasonic CT is used to reconstruct the image. The ART algorithm, the improved SART algorithm and the SIRT algorithm is introduced, while the steps of the algorithm were given. Through the theoretical calculation, the efficiency of different algorithms and imaging quality were analyzed.The measured organization model is established, while the internal organization of the velocity field and density field is set. And different probe form is set, through the simulation by toolbox k-wave, to get the emission and the received ultrasonic signal. According to the filtered back projection algorithm, in simulation analysis,data rearrangement and interpolation method are used to solve the problem that parallel beam algorithm cannot be applied on the ring probe. On the ring probe, the parallel beam and fan beam reconstruction algorithm are built and compared. And filter back projection algorithm of triangle array is simulated. According to the iterative reconstruction algorithm, a fast algorithm is proposed to obtain the coefficient matrix and improve the image quality, which helps to achieve the reconstruction algorithms. The acquisition data of triangular linear array is simulated by using SIRT algorithm. The feasibility of the proposed scheme is analyzed, and the results of the algorithms are compared and analyzed.