MTF compensation of baseline adjustable optical sparse aperture imaging system

For a single optical sparse aperture imaging system, because of the sub-mirrors’ dispersion and sparsity, the modulation transfer function (MTF) is unlikely to satisfy all frequencies due to inadequate sampling of the discrete sub-apertures. Thus, a baseline adjustable optical sparse aperture imaging system is proposed by expanding the sub-aperture array. Sufficient information from separate frequency regions can be maintained and fused. An improved Wiener filter algorithm based on the system's transfer function and noise features is designed for image restoration. Both the simulation and experiment prove that the proposed method can achieve a satisfactory MTF level and a clear reconstruction effect. The average peak signal to noise ratio is raised from 22.53 dB of degraded images to 29.17 dB of the restored images. The structural similarity index of the results is increased from 0.65 to 0.92. And compared with several conventional algorithms, scores of multiple evaluation indexes of the proposed method is the highest.