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目的:针对数字化医学超声成像时信号解调操作运算量较大的问题,简化正交解调操作,减少信号解调运算量。创新点:设计一对正交解调数字滤波器,省去传统解调方法中回波信号与载波信号相乘的操作,从而提高解调操作效率,并保证超声成像结果不变。方法:1.针对正交解调表达式特点,将混频操作与低通滤波操作相融合,从而提升正交解调运算效率(图1b);2.利用有限冲激响应滤波器系数对称特性,设计系数对称的解调滤波器(图2);3.进行仿真与在体(in vivo)实验,评估正交解调器效率与精度。结论:针对医学超声成像,提出一种高效的正交解调方法,在降低运算量的同时保证成像精度与传统正交解调方法相近。同传统正交解调方法一样,该方法还可用于旋转相位波束合成技术中。
Objective: To solve the problem of large amount of operation of signal demodulation in digital medical ultrasound imaging, to simplify the operation of orthogonal demodulation and to reduce the amount of signal demodulation. Innovative point: Design a pair of quadrature demodulation digital filter, eliminating the traditional demodulation method of echo signal and carrier signal multiplication operation, thereby enhancing the demodulation efficiency, and to ensure the same ultrasound imaging results. In order to enhance the efficiency of quadrature demodulation (Figure 1b), the symmetry characteristics of finite impulse response filter coefficients are improved by combining the mixing operation with the low-pass filtering operation. , Designing a symmetrical demodulation filter (Figure 2); 3. Performing simulation and in-vivo experiments to evaluate the efficiency and accuracy of the quadrature demodulator. Conclusion: For medical ultrasound imaging, an efficient orthogonal demodulation method is proposed, which can reduce the amount of computation and ensure the imaging accuracy similar to the traditional orthogonal demodulation method. Like traditional orthogonal demodulation methods, this method can also be used in rotating phase beamforming techniques.