As a computational technology, single-pixel microscopic imaging (SPMI) transfers the target’s spatial information into a temporal dimension. The traditional focusing method of imaging before evaluation is not applicable to the SPMI system. We propose a grating-free autofocus strategy derived from the physical mechanism of optical defocus. Maximizing the amplitude information of just one high-frequency point in the spectrum is all that is needed to achieve fast autofocus with the SPMI system. Accordingly, only four patterns need to be cyclically projected, enabling efficient localization of the focal plane based on the measurement data. We demonstrate SPMI autofocus experiments at micrometer and even nanometer depths of field. The proposed method can be extended to achieve SMPI autofocus with invisible optical pattern illumination.

中文翻译：

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用于单像素显微成像的无光栅自动对焦


作为一种计算技术，单像素显微成像（SPMI）将目标的空间信息转换为时间维度。传统的先成像后评估的聚焦方法不适用于SPMI系统。我们提出了一种源自光学散焦物理机制的无光栅自动对焦策略。使用 SPMI 系统实现快速自动对焦只需最大化频谱中一个高频点的幅度信息即可。因此，仅需要循环投影四个图案，从而能够基于测量数据有效地定位焦平面。我们演示了微米甚至纳米景深的 SPMI 自动对焦实验。所提出的方法可以扩展以实现具有不可见光学图案照明的 SMPI 自动对焦。