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Abstract: This work presents the fabrication and test of microlens arrays for Hartmann–Shack wavefront sensor, which were optimized, in terms of geometry, to be applied to the ophthalmic context. The optimization procedure was previously proposed by the authors and comprised the minimization of the wavefront reconstruction error through the use of genetic algorithm. The results indicated that arrays with 10 and 16 suitably located lenses could perform as good as those with a larger number of microlenses (25 or 36) in a rectangular geometry. In the present work, the sequence consisted in fabricating molds in silicon of the optimized array geometries; replicating the molds on polymer; and testing the final arrays on an optical bench, to comparatively assess the performance of the fabricated arrays. In general, final results corroborate with the ones predicted by simulations. [Copyright &y& Elsevier]

Abstract: In this paper, we propose a computational depth conversion method based on the lenslet model to display the orthoscopic 3D images in 3D integral imaging display. The proposed method permits the synthesis of elemental images for the orthoscopic 3D images at any arbitrary position without any restrictions and requires no additional procedure during the depth conversion process. Due to the lenslet model involved in the depth conversion procedure, the proposed method can broaden the flexibility of 3D image reconstruction in the integral imaging display system. We carry out the preliminary experiments to prove the feasibility of the proposed method. The experimental results reveal that the proposed method is an effective depth conversion method that allows the reconstruction of the orthoscopic 3D images at any arbitrary position. [Copyright &y& Elsevier]

Abstract: This paper describes a novel depth extraction method for 3D objects using the windowing technique in computational integral imaging with a lenslet array. The proposed method includes pickup through a lenslet array with a snapshot, introduction of slice image pairs obtained from the windowing technique, and extraction of depth information using block matching between the slice image pairs. Also, this paper presents a theory of how the windowing technique works for depth extraction and an analysis of how it enables us to have a depth image from low-resolution elemental images. A preliminary optical experiment indicates that the proposed method provides a substantial improvement on the depth extraction technique in computational integral imaging with a lenslet array. [Copyright &y& Elsevier]

Abstract: In this work we propose to optimize the microlens-array geometry for a Hartmann–Shack wavefront sensor. The optimization makes possible that regular microlens arrays with a larger number of microlenses are replaced by arrays with fewer microlenses located at optimal sampling positions, with no increase in the reconstruction error. The goal is to propose a straightforward and widely accessible numerical method to calculate an optimized microlens array for a known aberration statistics. The optimization comprises the minimization of the wavefront reconstruction error and/or the number of necessary microlenses in the array. We numerically generate, sample and reconstruct the wavefront, and use a genetic algorithm to discover the optimal array geometry. Within an ophthalmological context, as a case study, we demonstrate that an array with only 10 suitably located microlenses can be used to produce reconstruction errors as small as those of a 36-microlens regular array. The same optimization procedure can be employed for any application where the wavefront statistics is known. [Copyright &y& Elsevier]

• This optical system is a new type of integrated field of view imaging spectrometer. • The structure can simultaneously obtain high resolution with a wide field of view. • This new structure has the characteristics of simple structure, easy debugging. The currently available area array imaging spectrometer fails to provide high spectral resolution and fast imaging under a wide field of view (FOV). Therefore, this study proposes an integral field imaging spectrometer (IFIS) that uses an image-space telecentric lens (ISTL), a mask, and lenslet array (MLA) as the front structure of the system. The influence of their structural parameters on the optical performance of the system is analyzed by establishing ISTL and MLA models. We selected suitable structural parameters to establish the imaging spectrometer, and provided an experimental demonstration of the system. Our system can achieve a 1.6 nm spectral resolution in a wide FOV of 48.8°. Compared with other spectrometer designs, our system is characterized by a simple structure, wider FOV, and higher spectral resolution. [ABSTRACT FROM AUTHOR]