Research On The Improvement Method Of Three Dimensional Integral Imaging Display Quality

Three-dimensional(3D)display technology is the development trend of next generation display technology,which makes visual information perception more natural and realistic.Integral imaging(II)is considered to be one of the most prominent 3D display techniques.Integral imaging uses lens array to collect and reproduce the light field of the threedimensional scene,affording full color,full parallax and quasi-continuous viewing points within the viewing angle,working with incoherent light and can be viewed with the naked eye.Despite its many advantages,II suffers from the inherent drawbacks such as pseudoscopic effect,limited viewing angle,low viewing resolution and small image depth.Focusing on the improvement method of II display quality,this paper carries out the following research work:The principle of II pickup and display is analyzed.A model of the reconstructed light field degradation is established,considering the angle sampling interval and the size of the angle sampling element,which provides the theoretical basis for II system optimization and design.A one-step II system is proposed based on the novel feature of negative refractive index materials.The pseudoscopic imaging property of the negative refractive index material slab and imaging process of the spherical lens array in the negative refractive index material is theoretically investigated.The parameters of the near-range negative refractive index II system and far-field negative refractive index II system are deduced.Experiments show that the elemental image array captured by the proposed method can be used in the II display directly,which can reproduce three-dimensional image without pseudoscopic effect,avoiding the degradation caused by the two-step pickup method.This conversion process consumes no time,which is helpful for realization of a real-time II system.The lens array is the core component of II system.However,because of its small size,large number of arrays and the large volume,the aberration correction ability is weak,which restricts the II display quality seriously.In this paper,an II resolution enhancement method with metasurface-based lens array is proposed.The design principle of the metasurface is discussed,the phase distribution and aberration characteristics of the single-layer metasurface-based lens array is deduced.The aspherical phase profiles of the double-layer metasurface-based lens array are optimized to improve imaging performance.Experiments shows the metasurface-based lens array is suitable for high resolution II pickup and display.In conventional II system,the viewing angle is limited by the pitch and distance between the lens array and the display device.A three-dimensional II display system with non-uniform prism array is proposed to realize wide viewing angle.The non-uniform prism array can deflect the reconstructed light field to the optical axis of the lens array to eliminate the dislocations between reproduction areas for the elemental lens.Based on the monocentric optical design,we propose a novel three dimensional II display system with improved viewing angle using a monocentric lens array coupled with fiber bundle.The aberrations and viewing angle enhancement of the proposed method is analyzed.The defocused property and filling factor of the monocentric lens array is deduced.The simulation experiment shows that viewing angle more than 80 degree can be achieved by the proposed method.Focusing on relieving the trade-off relationship between the viewing resolution,viewing angle and depth of field,a method based on an aperture-tunable lens array for improving the viewing quality of II is proposed.The proposed method uses a liquid crystal panel to tune the aperture of the lens array dynamically.Thus the spatial sampling rate can be improved.Combining the temporal multiplexing technique,the viewing quality can be improved by the after-image effect of the human eye.For II with aperture-tunable lens array with 2×2 segmentation,the viewing resolution can be improved one time.In spite of many advantages of II,its optimal viewing zone is limited within a narrow range.An II display with tunable directional backlight is proposed.The viewing zone distribution and viewing angle enhancement of the proposed method is analyzed.The display parameters without crosstalk effect is deduced.The tunable directional backlight enables II to control the viewing zone dynamically.The flipped images are elimanated.By using time-sequential operation,the viewing angle of II display is improved.