Studies On Integral Imaging 3D Display

Humans are born with stereoscopic vision.People learned to draw perspectives to show the three dimensional feature of the space on a plane long time ago.But,whether the hand-drawn pictures or photos taken by camera just show the three dimensional feature from a certain angle,lack of depth information.The same problem exists in the modern display devices such as smart phone,tablet PC,HDTV and so on.People hope to see vivid scenery out of the screen but not on a plane.More than 100 years ago,the three dimensional display technology was born,and has been confirmed to be the final goal of display technology.After more than 100 years development,many kinds of 3D display techniques appeared,in which integral imaging is an excellent technique,providing full parallax,continuous viewpoints,full color and real-time 3D display,without using assistant devices,coherent light source and visual fatigue.But,due to the limits of the viewing resolution,viewing angle and depth range,integral imaging should be improved.This thesis studied high-property integral imaging 3D display from 3 aspects:high resolution integral imaging 3D display,2D/3D convertible integral imaging 3D display and integral floating 3D display.The main research works are as follows:1.We introduced the principle and category of integral imaging,and the principle of all-optics integral imaging and computational integral imaging.We introduced the characteristics of the 3 display modes of integral imaging.We analyzed the performance parameters and their relationships.We analyzed the advantages of integral imaging.2.We introduced typical resolution enhanced integral imaging methods,and analyzed the effective area in the elemental image of integral imaging,which influences the viewing resolution.Then we proposed a resolution enhanced integral imaging using two micro-lens arrays with different focal lengths for capturing and display.The method enlarges the elemental image effective area,avoiding pixel waste and increasing accepted information of viewer,that is viewing resolution.The processed elemental image array is displayed through a long focal length micro-lens array,increasing resolution while keeping the viewing angle and 3D image invariable.3.We introduced point light source integral imaging method and its viewing resolution limit,and introduced some improved methods and their disadvantages.We proposed a resolution enhanced integral imaging based on a dense point light source array.We use a 3x3 LED array and a collimating lens to form 9 parallel light rays of different directions,which generate a dense point light source array through the micro-lens array.The point light source number is 4 times of the number of the elemental lenses,so 4 times resolution enhancement is achieved.Compared with previous methods,the proposed method generates a dense point light source array with parallel diverging directions and uniform elemental image size,so the viewing angle keeps the same.We finally analyzed the color separation and blurring effect,reaching that the 2 problems can be avoided when the sizes of the point light source and the display pixel are the same.4.We introduced 2D/3D convertible integral imaging methods,and proposed 3 requirements should meets,and analyzed the principles and properties of typical methods.We proposed a 2D/3D convertible integral imaging display using an edge-lit light guide plate.The device is composed of a flat backlight,an edge-lit light guide plate and a liquid crystal display panel.In 3D mode,the edge light source is turned on,and the light guide plate generates a point light source array to form 3D images.In 2D mode,the flat backlight is turned on to illuminate the 2D images.We can switch different light sources to select different display modes.The advantages of the method are also explained.We analyzed the point light source aberration and point light source density optimization.We chose appropriate parameters to reduce the point light source aberration.We derived the projecting resolution and sampling resolution,and proposed a point light source density optimizing method.5.We introduced the principle of floating display,which can generate 2D image floating in mid-air.We analyzed the properties of several floating display methods.We introduced integral floating 3D display based on a floating lens,and analyzed the disadvantages such as narrow viewing window,imaging distortion and aberration.We proposed an integral floating 3D display using corner cube retro-reflector arrays,which combines integral imaging and floating display using corner cube retro-reflector arrays.The proposed method doesn't have the problems of the previous integral floating display,and can eliminate the depth-resolution limit and enlarge the complete viewing range for real image.We use reflective polarizer and quarter wavelength plate to improve the brightness with augmented reality feature.Highlights of the paper are as follows:1.We proposed a resolution enhanced integral imaging using two micro-lens arrays with different focal lengths for capturing and display.This method doesn't increase system complexity,and increase the obtained information of viewers by enlarging the effective area of elemental image.2.We proposed a resolution enhanced integral imaging based on a dense point light source array.Compared with previous methods,the proposed method generates a dense point light source array with parallel diverging directions and uniform elemental image size,so the viewing angle keeps the same.3.We proposed a 2D/3D convertible integral imaging display using an edge-lit light guide plate.It has advantages such as thin,low-cost,high optical efficiency,easy conversion and high quality in 2D mode.4.We proposed an integral floating 3D display using corner cube retro-reflector arrays,which combines integral imaging and floating display using corner cube retro-reflector arrays.The proposed method doesn't have the problems of the previous integral floating display,and can eliminate the depth-resolution limit and enlarge the complete viewing range for real image.