The Key Technology Of Performance Optimization Of Full Parallax Light Field Displays

Three-dimensional(3D)display technologies have attracted great interest owing to its ablity to display depth cues and correct geometric occlusion of 3D scenes.Full parallax light field display technology can reconstruct continuous viewing and full-color 3D images with full parallax,making it one of the most promising 3D display technologies.Unfortunately,current full parallax light field displays still suffer from image degradation,image flipping and limited viewing angle,which imits their application in various fields.Therefore,it is necessary to carry out the research on the performance improvement of full parallax light field displays to achieve high-quality 3D display effects.The main research contents and innovations of this dissertation are as follows:(1)Image quality enhancement of full parallax light field displaysIn the full parallax light field display,lens aberrations degrade the image quality of reconstructed 3D scenes.A wavefront aberration correction method is proposed to enhance the image quality with a pre-filtering function array.The wavefront aberration characteristic of the lens-array is analyzed and the light field distribution of the reconstructed image is calculated based on the wave optics theory.The pre-filtering function array is used to manipulate the elemental image array(EIA)to reduce the effects of lens aberrations.The validity of the proposed method is confirmed through simulations as well as optical experiments.Simulations demonstrate that the image quality measured in PSNR is increased by more than 2.5 dB.A 45-degree viewing angle integral imaging display with enhanced image quality is achieved.(2)The full parallax light field display without image flippingFor a conventional full parallax light field display,the use of lens arrays inevitably introduces flipped images beyond the field of view.To resolve the issue,the light path of the conventional display is analysed to explain the origin of flipped images and thus a twice-imaging lens array based full parallax light field display is presented.The proposed lens arrangement,which consists of a light-controlling lens array,a field lens array and an imaging lens array,allows the light rays from each elemental image only pass through its corresponding lens unit.The results of the simulation and the optical experiment prove that full-parallax 3D scenes without flipping can be reconstructed in 45° field of view with the proposed method.(3)Field of view enhancement for full parallax light field displaysThe current full parallax light field display suffers from narrow field of view,which limits its application in table-top 3D displays.A field of view enhanced method based on the thin-beam backlight is proposed.An LED light source and a Fresnel lens are used to provide the thin-beam backlight for the display.A lens array with small focal length is optimized to improve the field of view.However,the resolutions dereases as the field of view increases.In view of this contradiction,a beam splitting prism array and an image coding method based on pixel superposition are proposed.A table-top full parallax light field display with a field of view of 90°is achieved.