Evaluation of the impact of diffraction on image reconstruction in single-pixel imaging systems

In single-pixel coded aperture terahertz-imaging, the individual pixel size in the spatial terahertz modulator is usually comparable to the terahertz wavelength in order to obtain a sufficient spatial image resolution. Therefore, diffraction plays an important role in the imaging process and must be accurately taken into account when the image is computationally retrieved. For this reason, we analyzed the impact of diffraction from the spatial terahertz modulator on the quality of the reconstructed image in single-pixel coded aperture imaging. We observed that the most important fraction of the image information is already contained in the zero order diffracted radiation. Higher diffraction orders do not contain enough information to retrieve the image from them solely, yet can contribute to an improved image quality when added to the zero order information.