School of Biomedical Science, Huaqiao University, Quanzhou, China.
College of Engineering, Huaqiao University, Quanzhou, China.
J Biophotonics. 2023 Sep;16(9):e202300108. doi: 10.1002/jbio.202300108. Epub 2023 Jun 14.
We proposed a novel method to separate static and dynamic speckles based on spatial frequency domain filtering. First, the raw speckle image sequence is processed frame by frame through 2D Fourier transform, low-pass and high-pass filtering in the spatial frequency domain, and inverse Fourier transform. Then, we can obtain low- and high-frequency image sequences in the spatial domain. Second, we averaged both sequences in the time domain. After the above processing, we obtain the mean intensities of the dynamic and static speckle components in the spatial domain. Finally, we calculated the time-averaged modulation depth to map the 2-D blood flow distribution. Both phantom and vivo experiments demonstrated that the proposed method could effectively suppress the background non-uniformity and has the advantage of high computational efficiency. It also can effectively improve image contrast, contrast-to-noise ratio, and imaging dynamic range.
我们提出了一种基于空域滤波的新方法来分离静态和动态散斑。首先，原始散斑图像序列通过二维傅里叶变换、空域中的低通和高通滤波以及逆傅里叶变换逐帧处理。然后，我们可以得到空域中的低频和高频图像序列。其次，我们在时域中对两个序列进行平均。经过上述处理，我们得到了空域中动态和静态散斑分量的平均强度。最后，我们计算时间平均调制深度以绘制二维血流分布。体模和活体实验均表明，该方法能有效抑制背景不均匀性，且具有计算效率高的优点。它还可以有效提高图像对比度、对比噪声比和成像动态范围。
