Three-dimensional microwave imaging method via subaperture approximation

In this paper, we present a fast imaging method based on subaperture approximation (SA) technology for 3-D microwave imaging. Compare to 2-D microwave imaging, one of main problems in 3-D microwave imaging is its high computational cost caused by dimension expansion from 2-D to 3-D. This problem limits the application of 3-D microwave imaging. In practice, many 3-D imaging regions contain no targets or are shadowed by other scatterers, which is the sparse character of 3-D imaging regions. Based on this character, we propose a fast imaging method using the SA technology. The basic concept of the SA technology is using subapertures to pick out the regions of interest, then image in the regions of interest. The computational cost of this method is analyzed, and some experimental results are conducted to demonstrate the feasibility of this method. We find that the computational cost of SA 3-D imaging method is far smaller than that of the 3-D BP imaging method.