Efficient Terahertz Wide-Angle NUFFT-Based Inverse Synthetic Aperture Imaging Considering Spherical Wavefront

Area of Science:

• Electromagnetics
• Imaging Science
• Terahertz Technology

Background:

• Wide-angle imaging is crucial for applications like nondestructive detection.
• Spherical wavefront effects in terahertz imaging require specialized compensation.
• Existing methods may lack efficiency for wide-angle terahertz applications.

Purpose of the Study:

• To develop an efficient wide-angle inverse synthetic aperture imaging method for terahertz applications.
• To accurately model and compensate for spherical wavefront effects.
• To accelerate the image reconstruction process.

Main Methods:

• Establishment of an echo signal model considering spherical wave assumptions.
• Implementation of a wavefront curvature compensation method accelerated by 1D fast Fourier transform (FFT).
• Utilization of fast Gaussian gridding (FGG)-based nonuniform FFT (NUFFT) for accelerated image reconstruction.

Main Results:

• Proof-of-principle experiments validate the proposed imaging method.
• The method demonstrates effectiveness and efficiency compared to the convolution back-projection (CBP) algorithm.
• Accurate reconstruction of wide-angle terahertz inverse synthetic aperture images is achieved.

Conclusions:

• The presented terahertz imaging method is effective and efficient for wide-angle applications.
• The method is suitable for nondestructive detection.
• It provides a viable solution for calculating far-field Radar Cross Sections (RCSs) in the terahertz regime.