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

Abstract

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 mid-frequency 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.