Optical Sparse Aperture Research Articles

Non-iterative wavelet-based deconvolution for sparse aperturesystem

Optical sparse aperture imaging is a promising technology to obtain high resolution but with a significant reduction in size and weight by minimizing the total light collection area. However, with the decreasing of collection area, its OTF is also greatly attenuated, and thus the directly imaging quality of sparse aperture system is very poor. In this paper, we focus on the post-processing methods for sparse aperture systems, and propose a non-iterative wavelet-based deconvolution algorithm. The algorithm is performed by adaptively denoising the Fourier-based deconvolution results on the wavelet basis. We set up a Golay-3 sparse-aperture imaging system, where the imaging and deconvolution experiments of the natural scenes are performed. The experiments demonstrate that the proposed method has greatly improved the imaging quality of Golay-3 sparse-aperture system, and produce satisfactory visual quality. Furthermore, our experimental results also indicate that the sparse aperture system has the potential to reach higher resolution with the help of better post-processing deconvolution techniques.

Effect of noise on the performance of image restoration in an optical sparse aperturesystem

The optical sparse aperture system achieves almost the same resolution as a conventionalfull filled aperture telescope but with a lower weight and cost. However, the greatly reducedmodulation transfer function (MTF) causes significant blurring and loss of contrast in theobserved image. The image restoration algorithms can correct the blurring if the actualoptical transfer function (OTF) or point spread function (PSF) is given. Usually, the OTFand PSF captured by experiment is assumed to be the actual OTF and PSF, which areconsidered as the best match for image restoration. However, the noise contained withinthe captured PSF or OTF may prevent successful restoration. Here, we investigatethe restored image by the captured PSF and the calculated PSF based on arrayconfiguration. The calculated PSF produced a better result than the captured PSF.

光学稀疏孔径系统复合阵列构造对系统成像的影响

光学稀疏孔径系统复合阵列构造对系统成像的影响

Experimental study on imaging and image restoration of optical sparse aperture systems

Optical sparse-aperture systems can be designed to obtain a high resolution when imaging an astronomical object. These systems are the arrays synthesized by several small filled imaging systems. A principal experiment is set up for an optical sparse-aperture system by which imaging of an extended complex object is achieved. Image restoration of the direct output by the sparse-aperture system is performed by measuring the point-spread functions (PSF) and by using a Weiner filter. The correlation coefficient is proposed as a criterion to determine the optimal parameter and to evaluate the performance of the algorithms. The results show that among the three kinds of configuration models, the Tri-Arm array configuration can produce the highest resolution and largest correlation coefficient value after the restoration. Accordingly, the experimental data, demonstrate that an optical sparse-aperture system can achieve almost the same resolution and image quality as an equivalent filled system.