Smith S W, von Ramm O T
Center for Devices and Radiological Health, Food and Drug Administration, Rockville, MD 20857.
Ultrason Imaging. 1988 Jul;10(3):153-70. doi: 10.1177/016173468801000301.
A new online signal processing technique is described to reduce speckle noise in ultrasound images. In the imaging system, a focused piston transducer is divided into thirty-two sectors. In the receive mode, parallel signal processing arranges the sectors into eight maltese crosses. The rf signals of the perpendicular arms of each cross are multiplied in a phase sensitive process. The orthogonal receive mode multiplication is designed to reduce side lobes resulting from the sector shapes while maintaining lateral resolution through the use of the full aperture diameter. The signals from the crosses are then combined via postdetection summation. Six of the eight crosses perform successfully. The six maltese crosses show decorrelated signals equivalent to four independent samples of the speckle noise which decreases noise contrast by a factor of two with no measureable loss of spatial resolution. Post summation compression is included to retain the conventional signal dynamic range. Parallel signal processing maintains the normal image line rate. Images of tissue-mimicking phantoms including speckle targets show improved detectability of simulated lesions.
描述了一种新的在线信号处理技术，用于减少超声图像中的斑点噪声。在成像系统中，一个聚焦活塞换能器被分成32个扇区。在接收模式下，并行信号处理将这些扇区排列成八个马耳他十字。每个十字垂直臂的射频信号在一个相敏过程中相乘。正交接收模式乘法旨在减少扇区形状产生的旁瓣，同时通过使用全孔径直径保持横向分辨率。然后通过检测后求和将来自十字的信号进行组合。八个十字中有六个成功运行。这六个马耳他十字显示出与斑点噪声的四个独立样本等效的去相关信号，这将噪声对比度降低了一半，且空间分辨率没有可测量的损失。包括后求和压缩以保持传统的信号动态范围。并行信号处理保持正常的图像线速率。包括斑点目标的组织模拟体模图像显示出模拟病变的可检测性得到了改善。
