Zhang Pengfei, Manna Suman K, Miller Eric B, Jian Yifan, Meleppat Ratheesh K, Sarunic Marinko V, Pugh Edward N, Zawadzki Robert J
UC Davis Eye-Pod Small Animal Ocular Imaging Laboratory, Department of Cell Biology and Human Anatomy, University of California Davis, 4320 Tupper Hall, Davis, CA 95616, USA.
Center for Neuroscience, 1544 Newton Court, University of California Davis, Davis, CA 95618, USA.
Biomed Opt Express. 2019 Jan 15;10(2):552-570. doi: 10.1364/BOE.10.000552. eCollection 2019 Feb 1.
Speckle is an inevitable consequence of the use of coherent light in imaging and acts as noise that corrupts image formation in most applications. Optical coherence tomographic imaging, as a technique employing coherence time gating, suffers from speckle. We present here a novel method of suppressing speckle noise intrinsically compatible with adaptive optics (AO) for confocal coherent imaging: modulation of the phase in the system pupil aperture with a segmented deformable mirror (DM) to introduce minor perturbations in the point spread function. This approach creates uncorrelated speckle patterns in a series of images, enabling averaging to suppress speckle noise while maintaining structural detail. A method is presented that efficiently determines the optimal range of modulation of DM segments relative to their AO-optimized position so that speckle noise is reduced while image resolution and signal strength are preserved. The method is active and independent of sample properties. Its effectiveness and efficiency are quantified and demonstrated by both non-biological and biological applications.
散斑是成像中使用相干光不可避免的结果，在大多数应用中它作为噪声干扰图像形成。光学相干断层扫描成像作为一种采用相干时间选通的技术，也受到散斑的影响。我们在此提出一种用于共焦相干成像的、与自适应光学（AO）内在兼容的抑制散斑噪声的新方法：用分段变形镜（DM）调制系统光瞳孔径中的相位，以在点扩散函数中引入微小扰动。这种方法在一系列图像中产生不相关的散斑图案，使得能够通过平均来抑制散斑噪声，同时保持结构细节。提出了一种方法，该方法能有效地确定DM段相对于其AO优化位置的最佳调制范围，从而在保留图像分辨率和信号强度的同时降低散斑噪声。该方法是主动的，且与样品特性无关。通过非生物和生物应用对其有效性和效率进行了量化和验证。
