Opt Lett. 2018 Jul 15;43(14):3449-3452. doi: 10.1364/OL.43.003449.
A two-step dual-wavelength phase imaging method with total variation (TV) regularization in digital holographic microscopy (DHM) is presented. The rough height map is first denoised with TV regularization, and then it is used as a guiding map for accurate phase unwrapping. By combining the principle of dual-wavelength interferometry and TV regularization, the problem of phase unwrapping is converted into a minimization problem that can be efficiently solved with the Split Bregman algorithm. The proposed algorithm allows a synthetic wavelength that can be arbitrarily large in principle to a single wavelength, while the accuracy of the phase map can achieve the same level in single-wavelength DHM. Moreover, the unwrapping method is robust to the change of weighting parameters. Comparative topographic measurements of a sample with abrupt steps are illustrated, and the results verified the effectiveness of the method.
提出了一种两步双波长相位成像方法，该方法在数字全息显微镜 (DHM) 中使用全变差 (TV) 正则化。首先用 TV 正则化对粗糙高度图进行去噪，然后将其用作精确相位解包裹的指导图。通过结合双波长干涉原理和 TV 正则化，将相位解包裹问题转换为一个可以用分裂布格曼算法高效求解的最小化问题。所提出的算法允许一个在理论上可以任意大的合成波长转换为单波长，而相位图的精度可以达到单波长 DHM 的相同水平。此外，该解包裹方法对加权参数的变化具有鲁棒性。对具有明显台阶的样品进行了对比形貌测量，结果验证了该方法的有效性。
