Considering the limited pixel number and large pixel size of common display panel, the captured elemental images (EIs) array of high density pixels cannot be reconstructed sufficiently in the display process of integral imaging, because of matched display requirement. To solve this problem, this paper presents a novel approach to improve integral imaging resolution by designing a coded sub-pixel mask on common display panel. Specifically, multi-pixels in the captured EIs are displayed in a pixel in the common display panel with time multiplexing along with the corresponding aperture switched on/off of the coded sub-pixel mask periodically, in which the resolution of the reconstructed image is determined by the coded aperture size of the sub-pixel mask rather than the pixel size of the display panel. Then, the mapping relationship between the displayed pixel and the position of the switched on aperture of the coded sub-pixel mask is established theoretically. Computational reconstruction and optical experimental results show that this method can match the pixel number of the captured EIs with that of the display panel and the resolution of integral imaging can be improved significantly.

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To solve the pseudoscopic problem, we propose a one-step integral imaging system with negative refractive index materials, which can avoid the deterioration in resolution inherent to the optical or digital two-step processes. Specifically, the proposed method is based on the novel feature of negative refractive index materials, bending light to a negative angle relative to the surface normal. The pseudoscopic imaging property of the negative refractive index material slab is theoretically investigated. For formation of orthoscopic reconstructed images, the matching condition of the negative index lens array and the positive index lens array is deduced. Two types of conceptual prototypes of integral imaging system with negative refractive index materials are designed. Experimental results show the validity of the proposed method. To the best of our knowledge, this is the first time to explore the application of negative index materials in eliminating the pseudoscopic effect in integral imaging.

A method for improving the viewing quality of integral imaging (II) is proposed, based on using an aperture-tunable lens array (LA). The proposed method uses a liquid crystal (LC) panel without a backlighting unit to tune the aperture of an LA dynamically. The shape and transmittance of the aperture can be controlled arbitrarily by programming the state of the pixels on the LC panel. Adding the temporal multiplexing technique, the viewing quality can be improved by the after-image effect of the human eye. Moreover, the relationships between the lateral resolution and the aperture tuning pattern and the depth of field and the aperture tuning pattern are derived, respectively. The product of the depth of field, the lateral resolution squared, and the lateral viewing range is proposed as a new figure of merit for an II system. Experimental results show the validity of the proposed method.