Transport of intensity equation (TIE) is a well-established non-interferometric phase retrieval approach that enables quantitative phase imaging (QPI) by simply measuring intensity images at multiple axially displaced planes. The advantage of a TIE-based QPI system is its compatibility with partially coherent illumination, which provides speckle-free imaging with resolution beyond the coherent diffraction limit. However, TIE is generally implemented with a brightfield (BF) configuration, and the maximum achievable imaging resolution is still limited to the incoherent diffraction limit (twice the coherent diffraction limit). It is desirable that TIE-related approaches can surpass this limit and achieve high-throughput [high-resolution and wide field of view (FOV)] QPI. We propose a hybrid BF and darkfield transport of intensity (HBDTI) approach for high-throughput quantitative phase microscopy. Two through-focus intensity stacks corresponding to BF and darkfield illuminations are acquired through a low-numerical-aperture (NA) objective lens. The high-resolution and large-FOV complex amplitude (both quantitative absorption and phase distributions) can then be synthesized based on an iterative phase retrieval algorithm taking the coherence model decomposition into account. The effectiveness of the proposed method is experimentally verified by the retrieval of the USAF resolution target and different types of biological cells. The experimental results demonstrate that the half-width imaging resolution can be improved from 1230 nm to 488 nm with 2.5 × expansion across a 4 × FOV of 7.19 mm², corresponding to a 6.25 × increase in space-bandwidth product from ∼5 to ∼30.2 megapixels. In contrast to conventional TIE-based QPI methods where only BF illumination is used, the synthetic aperture process of HBDTI further incorporates darkfield illuminations to expand the accessible object frequency, thereby significantly extending the maximum available resolution from 2NA to ∼5NA with a ∼5 × promotion of the coherent diffraction limit. Given its capability for high-throughput QPI, the proposed HBDTI approach is expected to be adopted in biomedical fields, such as personalized genomics and cancer diagnostics.

基于强度传输方程的非干涉相位恢复方法是通过对强度图像求解方程来获取相位的一种途径。在图像采集过程中，对聚焦图像的选择是很重要的。但该过程通常是由主观方法来确定，从而导致聚焦定位不准确，进而影响相位恢复结果的精度。首先，提出了一种基于强度传输方程的自适应聚焦相位恢复方法；其次，使用边缘占空比对采集图像进行定位，在求解相位之后进行循环角谱传播，直到边缘占空比定位位置不变，即被认为是定位到了最佳聚焦位置；最后，再使用强度传输方程求解样本的相位。结果证明：该方法不仅提高了相位恢复的准确性而且减少了获取大量图像的次数。在模拟实验中，恢复相位与原始相位的相关系数达到0.9866，均方根误差为0.3050。在实际的微透镜阵列实验中，用所提出的相位恢复方法恢复出的微透镜高度与真实高度误差仅为5.7%，证明了在显微成像领域，所提算法可以定位到最优聚焦位置，有利于自动聚焦技术的发展，进而提高相位恢复的精度。

相位恢复是利用能观测到的强度信息恢复原始相位信息。强度传输方程（TIE）作为一种传统的非干涉相位恢复技术，只需通过测量至少两个相近平面的强度信息即可计算出相位信息。这种方法通常需要通过移动被测物体或摄像机来获取强度图像，不可避免地会产生机械误差。提出了一种新的相位恢复方法：与色散融合的混合相位恢复算法（CD-HPR）。通过设置不同波长的光通过单透镜系统得到物体在同一位置成的像，这样不需要机械运动就能获得聚焦和散焦图像强度，然后结合散焦量与波长之间的关系计算出散焦量，再用强度传输方程计算初始相位信息。角谱迭代算法的使用较好地改进了初始相位值。在仿真实验中，该方法恢复的相位与原始相位之间的均方差为0.1076；同时，通过实验恢复了透镜阵列的相位，实验结果与实际参数的误差为3.4%，证明了该方法的正确性和有效性。该方法扩展了传统方法要求光源为单色的局限性，提高了计算精度。