Application of Autofocus Algorithm in Millimeter-Wave Narrowband Holographic 3D Imaging

A single-frequency millimeter-wave imaging system can only acquire two-dimensional information of the target. Moreover, during the imaging process, the position of the reference plane needs to be adjusted in real time according to the distance from the target to the scanning array to maintain high-quality focusing effect. Therefore, in this paper, a single-frequency millimeter wave imaging autofocus algorithm is proposed by using the amplitude value of the inversion image as the basis for evaluating the image focus. The method can realize automatic focusing of narrow-band holographic imaging, and at the same time, for distributed targets in practical application scenarios, the method of multi-focus image fusion of slices is used to realize all-focus inversion imaging of multiple targets. Finally, simulation experiments verify the effectiveness of the method.