  Active Millimeter wave (AMMW) imaging is of interest as it has played
important roles in wide variety of applications, from nondestructive test to
medical diagnosis. Current AMMW imaging systems have a high spatial resolution
and can realize three-dimensional (3D) imaging. However, conventional AMMW
imaging systems based on the synthetic aperture require either time-consume
acquisition or reconstruction. The AMMW imaging systems based on real-aperture
are able to real-time imaging but they need a large aperture and a complex
two-dimensional (2D) scan structure to get 3D images. Besides, most AMMW
imaging systems need the targets keep still and hold a special posture while
screening, limiting the throughput. Here, by using beam control techniques and
fast post-processing algorithms, we demonstrate the AMMW 3D scan real-time
imaging mechanism with a line antenna array, which can realize 3D real-time
imaging by a simple one-dimensional (1D) linear moving, simultaneously, with a
satisfactory throughput (over 2000 people per-hour, 10 times than the
commercial AMMW imaging systems) and a low system cost. First, the original
spherical beam lines generated by the linear antenna array are modulated to fan
beam lines via a bi-convex cylindrical lens. Then the holographic imaging
algorithm is used to primarily focus the echo data of the imaged object.
Finally, the defocus blur is corrected rapidly to get high resolution images by
deconvolution. Since our method does not need targets to keep still, has a low
system cost, can achieve 3D real-time imaging with a satisfactory throughput
simultaneously, this work has the potential to serve as a foundation for future
short-range AMMW imaging systems, which can be used in a variety of fields such
as security inspection, medical diagnosis, etc.
