Abstract: In medical ultrasound imaging field, in order to obtain high resolution and correct the focusing errors resulting from the sound-velocity inhomogeneities of the tissue, synthetic focusing imaging using the generalized coherence factor is presented. According to the characteristic of synthetic focusing, the echo data is processed by using twice generalized coherence factor. The received aperture data from single transmit array element is used to calculate the generalized coherence factor. The factor is used to weight the sum of received data to obtain single process result. All process results are processed using the generalized coherence factor again. The simulated results show that the method proposed in this paper in the aspects of resolution, contrast and correcting focusing errors is better than conventional DAS（Delay And Sum） and synthetic focusing algorithm.

Key words: ultrasound imaging, sound-velocity inhomogeneities, generalized coherence factor, synthetic focusing

摘要： 在医学超声成像中，为了提高分辨率并修正由生物组织的声速不均匀性引入的聚焦误差，提出将广义相干系数引入到合成聚焦成像中。并针对合成聚焦数据的特点，对回波数据进行双次广义相干系数算法处理。由单个阵元发射，所有阵元接收的数据计算广义相干系数；将接收数据求和后与该系数进行加权，得到单次发射接收信号的处理结果；对各次发射接收信号的处理结果再一次使用广义相干系数进行处理。仿真实验结果表明，该方法在提高图像分辨率、对比度以及校正聚焦误差上都明显优于传统的延时叠加与合成聚焦成像方法。

关键词: 超声成像, 声速不均匀性, 广义相干系数, 合成聚焦