| Human vision is the most important way for humans to perceive the objective world,and obtain outside information.As an important technology for the presentation of visual information,display technology is devoted to the most realistic reconstruction of information in the objective world,and it is of great significance for satisfying the visual needs of humans.The human visual system(HVS)is composed of binoculars and always perceives the objective world in a three-dimensional(3D)way.It can not only perceive information such as color and brightness in the objective world,but also perceive different perspectives of the objective world at the same time.However,the current mainstream display technology which records and displays information in two-dimension(2D)way,can only record information from a single viewpoint of the objective world,and cannot meet human needs for full recognition of the objective world.The recording and displaying of information in 3D way is the irresistible trend of the development of display technology.With the characteristics of high dynamic,large viewing angle,true color,and high resolution,the true 3D display can realistically restore the objective world in multiple dimensions such as depth,color,brightness,and contrast,and is the future of display technology.And it is of great significance to meet the development of science and technology,also the development of the national economy.The research of visual perception based naked-eye computational 3D display is an important exploration of the true 3D display.This research work is performed based on the current naked-eye 3D display technologies,including viewpoint based autostereoscopic display and light field based autostereoscopic display.By introducting of human visual perception models and computational display technologies,and combined with optical design,the research aims to improve the performance of the naked-eye 3D display in aspects of spatial resolution,angular resolution,temporal resolution,luminance contrast and color,by proposing novel 3D display architectures and 3D content processing methods.This display technology aims to provide viewers with a more vivid,accurate,and highly immersive visual experience.Specifically,the main research points and innovation results of the reasearch are listed as follows:(1)A large depth of field frontal multi-projection 3D display with uniform light field distributionDue to the limited angular resolution,an autostereoscopic display device generally exhibits a certain depth of field(DOF)limitation,and the portions of the 3D scene,which the displayed depth exceeds the DOF,exhibit defocus blur and degenerative display resolution,and this damages the viewer's 3D visual experience.Therefore,in order to improve the DOF and the 3D visual experience of the display,it is necessary to propose a naked-eye 3D display with improved angular resolution.In this paper,a novel approach to achieve 3D display with large DOF and uniform light field distribution based on frontal multi-projection is proposed.For multi-projection autostereoscopic 3D display,a 3D projection screen design scheme based on aberration optimization is proposed.In order to improve the angular resolution of the display and realize the 3D display with dense viewpoint,a multi-period projector array arrangement method utilizing the periodic distribution of viewing zone of autostereoscopic display is designed.The light field constructed by the display system is modeled,and the uniform distribution of light field is achieved by optimizing the arrangement strategy.In order to achieve synchronization control of multiple projectors,a multi-view content synchronous rendering and control method was proposed.Based on those,a 3D display system with a large DOF and uniform light field distribution composed of a lenticular lens based 3D projection screen and 30 projectors is implemented.The display system has a display size of 85 inches(1800 mm × 1200 mm),a spatial resolution of 1200 × 720,a DOF of[-590 mm,590 mm],and a viewing angle 48°,the fluctuation of the intensity distribution at viewing plane is less than 7.65%.(2)Light field diplay with large viewing angle and high spatial resolutionLight field display constructs the light field of objective world by combining of a multi-projection light source and a light-controlling optical device.It can provide viewers with multiple perspectives of the world,and this conforms to the physical laws of the human observing the objective world.Thus,this paper studies the construction method of the light field,and based on those,two kinds of light field display methods are proposed,which are listed as follows.a)A 360-degree light field display based on high-speed projectionIn this paper,a 360-degree light field display designing method based on high-speed projection is proposed.The display is composed of an ultra high-speed projector and a rotating 3D projection screen with direction deflection and directional scattering,and achieve the purpose of building a 360-degree visual light field in a time-division multiplexing way.The 3D projection screen is prepared by laminating a directional deflective microprism array and a holographic function screen(HFS)with the ability of directional diffusion.The spatial resolution of constructed light field depends on the resolution of the projector.The viewing angle of 360 degrees conforms to the physical laws of the human observing the objective world,and enhances the visual performance of the 3D display.The diameter of display area of the proposed 360-degree light field display in this paper is 400 mm,the spatial resolution is 768x768,and the number of viewpoints is 300.b)A high-resolution light field display based on double-layer liquid crystal(LC)polarization modulationTo release the restriction between the spatial resolution and angular resolution of the integrated imaging light field display,a novel high-resolution light field display implementation method based on double-layer LC polarization modulation is proposed in this paper.By designing a display based on double-layer LC polarization modulation with pixel offset,a super-resolution display unit exceeding the physical resolution limition of a single-layer LCD is realized,and combining this with the lense array and the HFS,a high-resolution light field display is achieved.The display builds a light field with both high angular resolution and spatial resolution by increasing the total amount of display pixels.The high-resolution light field display based on double-layer LC polarization modulation built in this paper has a display screen of 15.6 inches,a viewpoints number of 128×128,a viewing angle of 40°×40°,and can display the light field with a spatial resolution of 433x236.(3)Display contrast improvement of multi-projection 3D display through tone mapping based optimizationIn a multi-projection 3D display,the 3D projection screen usually shows a certain reflectivity scattering and transmission scattering,thus the multi-projection 3D display suffers from decreased display local contrast due to the crosstalk of multi-projection 3D contents.For this reason,this paper innovatively proposes a multi-projection 3D light field display contrast optimization method based on tone mapping operator.In this method,the display luminance modeld of multi-projection 3D display light is firstly proposed,then a difference prediction model of luminance and contrast based on human visual perception is introduced,and a multi-view content adjustment operation based on tone mapping operation is adopted to achieve a minimum perceived contrast difference between the display light field and the target light field,thus improving the local contrast of the the constructed light field and the quality of the 3D display.(4)Depth-perception preserved 3D display depth remappingIn the naked-eye 3D display,there exists the defocusing phenomenon caused by the display depth exceeding the DOF of the display.The conventional depth remapping method usually improves the display definition by reducing the display depth of 3D content.A novel depth-perception preserved 3D content remapping method is presented in this paper,and the Cornsweet illusion based depth remapping method is introduced to enhance the depth-perception by augmenting the contrast at area where the depth distribution is discontinus.Then the 3D display quality measurement objective function based on the models of perceptual contrast difference prediction and perceptual depth difference prediction is constructed.By optimizing the objective function,the 3D display achieve the trade-off between definition improvement and the perceptual depth reduction,and finally depth-perception preserved 3D display depth remapping is achieved. |
PDF Full Text Request