Super Sub-Nyquist Single-Pixel Terahertz Imaging Using Hadamard Basis

We present a super sub-Nyquist Hadamard single-pixel terahertz (THz) imaging system in which the THz waves are modulated by a digital micromirror device and a laser driver. Spatial coding of the THz radiation is performed using the cake-cutting (CC)-order Hadamard basis. THz images are reconstructed from a series of coding sequences of the measurement intensity. We prove that with the use of super sub-Nyquist sampling, single-pixel THz imaging with 87% fidelity and a signal-to-noise ratio of more than 23 dB can be achieved using 10% of the CC-order Hadamard basis patterns. The total variation regularization algorithm is shown to have higher robustness to noise than the Hadamard transform and thus offers a good technical solution for single-pixel THz imaging.