High-speed all-in-focus 3D imaging technology based on the liquid lens focus scanning

A large open aperture in an optical system can capture high-resolution images but yields a shallow depth of field. To overcome this issue, we propose a method for improving microscopy imaging systems by using a variable-focus liquid lens to achieve 3D focus scanning. Specifically, the focal length of the imaging system was changed by the liquid lens, and a sequence of 12 images was captured in different focal planes. The image scale was adjusted according to the change in focal length, and the phase of the image was corrected by the phase only correction method. Then the in-focus pixels were abstracted by employing the Laplacian operator. Finally, an all-in-focus sharp image was generated, and a depth map was obtained. Additionally, to accelerate the processing speed, the Fast Fourier Transform image processing during phase correction was optimized. Meanwhile, we propose a parallel optimization solution for the original processing flow.