Salomonsson G, Löfström B
Ultrason Imaging. 1985 Jul;7(3):225-43. doi: 10.1177/016173468500700303.
Attenuation in tissue decreases both the amplitude and the bandwidth of a reflected ultrasonic signal. Only the amplitude is restored in conventional ultrasonic equipment by amplifying the signal in a time-gain-compensator. This paper describes a method for restoring both the amplitude and bandwidth of the signal and an implemention of this method is proposed. This consists of two main parts: a device for estimating the attenuation and a time-variable circuit. The time-variable circuit is controlled by the estimated attenuation such that its transfer function approximates the inverse of the transfer function of the attenuation within the transducer passband. Its output is then almost independent of the attenuation and contains information on the texture of the tissue. Both the texture and attenuation estimates are displayed graphically. The quality of the image of the texture can be improved by choosing a wideband transducer, since it is almost exclusively dependent of transducer bandwidth.
组织中的衰减会降低反射超声信号的幅度和带宽。在传统超声设备中，仅通过时间增益补偿器对信号进行放大来恢复幅度。本文描述了一种恢复信号幅度和带宽的方法，并提出了该方法的一种实现方式。它主要由两部分组成：一个用于估计衰减的装置和一个时变电路。时变电路由估计的衰减控制，使其传递函数在换能器通带内近似于衰减传递函数的倒数。其输出 then 几乎与衰减无关，并包含有关组织纹理的信息。纹理和衰减估计都以图形方式显示。由于纹理图像的质量几乎完全取决于换能器带宽，因此通过选择宽带换能器可以提高纹理图像的质量。
