As an optical misalignment sensing technique, phase diversity can estimate the pupil phase from pairs of simultaneously recorded focused and defocused images, then the misalignment error is obtained.

• 基于相位差法的检测技术，主要是利用在焦面和离焦位置上同时采集的一对图像，对光瞳上的相位分布进行恢复，从而得出子望远镜间的微小失调误差。