This work is concerned with optical imaging in strongly diffusive environments. We consider a typical setting in optical coherence tomography where a sample is probed by a collection of wavefields produced by a laser and propagating through a microscope. We operate in a scenario where the illuminations are in a speckle regime, namely fully randomized. This occurs when the light propagates deep in highly heterogeneous media. State-of-the-art coherent techniques are based on the ballistic part of the wavefield, that is the fraction of the wave that propagates freely and decays exponentially fast. In a speckle regime, the ballistic field is negligible compared to the scattered field, which precludes the use of coherent methods and different approaches are needed. We propose a strategy based on blind source separation and total variation deconvolution to obtain images with diffraction-limited resolution. The source separation allows us to isolate the fields diffused by the different scatterers to be imaged, while the deconvolution exploits the speckle memory effect to estimate the distance between these scatterers. Our method is validated with numerical simulations and is shown to be effective not only for imaging discrete scatterers, but also continuous objects.

翻译：本研究关注强扩散环境下的光学成像问题。我们考察光学相干断层扫描中的典型场景：样本受到由激光产生并经由显微镜传播的波场集合探测。我们在照明处于散斑状态（即完全随机化）的场景下开展工作，这种情况发生于光在高度异质介质中深度传播时。当前最先进的相干技术基于波场的弹道部分，即自由传播且呈指数级快速衰减的那部分波。在散斑状态下，弹道场相较于散射场可忽略不计，这排除了相干方法的使用，因此需要不同的方法。我们提出一种基于盲源分离与全变分去卷积的策略，以获得衍射极限分辨率的图像。源分离使我们能够隔离待成像的不同散射体所扩散的场，而去卷积则利用散斑记忆效应来估计这些散射体之间的距离。我们的方法通过数值模拟得到验证，结果表明其不仅对离散散射体成像有效，对连续物体成像同样有效。