Mid-frequency contrast compensation for sparse aperture imaging systems by a larger sub-aperture

Sparse aperture imaging systems (SAISs) always suffer mid-frequency contrast loss because of dispersion and sparsity. This paper introduces an efficient method to enlarge the sub-aperture with the most significant effect on midfrequency contrast compensation. This method is implemented by evaluating the mean square error between the modulation transfer function (MTF) of an SAIS and a monolithic aperture system with matching cutoff frequency. Two array configurations with different sub-apertures enlarged by various magnifications are simulated and their MTFs are analyzed. Subsequently, experiments are conducted by enlarging a sub-aperture within an array configuration at different magnifications. The results confirm the method's effectiveness. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.