Research On Techniques Of Dynamic Holographic Three-dimensional Display Based On Grayscale Images

Holographic display is a kind of display technology that enable the viewer to observe the three-dimensional?3D?scene with naked eyes.It has a potential application and research value in MEMS?Micro-Electro-Mechanical System?,medical treatment,commerce,scientific research,military and entertainment.Two-dimensional?2D?carrying medium is used to project 2D images with binocular parallax in the traditional 3D display technology,like stereo display,integrated imaging and light field.These projected images without depth can't meet the whole visual function of human eyes and will lead to eye strain for a long time to observe.Compared to the traditional 3D display technology,holographic display technology,which store 3D information of an object,can satisfy the requirements of naturalistic observation.These methods for holographic display are divided into two types:3D existing object is recorded by laser and virtual object is simulated in a computer.Using a simple method to solve the rigorous circumstance and cost existing in above methods in order to project holographic 3D images has important research significance and value,a method based on grayscale images is proposed for dynamic holographic display.The main our researches are listed below:?1?Basic theories of computer holography and constructed images are analyzed.Analytical result shows that,kinoform is a kind of phase hologram characterized by without twin image in image-plane,high diffraction efficiency and high peak signal to noise ratio.The iterative fourier algorithm as the optimization algorithm for computer generated hologram is introduced and analyzed.?2?A method based on the intensity curve of a 2D image is proposed for phase conjecture.The gray-level gradient of region of interest is obtained.The phase information is calculated by fitting the gray curve obtained by transforming the different positions of two perpendicular line in 2D intensity image.The continuous phase is quantized to 0 and2p according to the gray gradient values.The numerical simulated results of proposed method and phase retrieval are analyzed.MSE values of proposed method is9.327?10^-7,which is much less than1.5822?10^-6of TIE requires several operations.?3?A holographic display method combing the amplitude of real picture and the actual phase distribution,which is obtained by above method,is proposed in order to reduce speckle noise,eliminate twin image and zero-order image.The numerical reconstruction results of proposed method and dynamic pseudorandom-phase tomographic computer holography?DPP-TCH?are compared.The result shows that,not only the complexity the calculation but also the speckle noise for proposed method are less than that needed for DPP-TCH.?4?The phase modular property of phase-only liquid crystal spatial light modulator?LC-SLM?are measured.A dynamic holographic 3D projection system based on LC-SLM and different carrying mediums is introduced.Experimental results verify that,by proposed method,a vivid holographic reconstructed projection image with real phase information can be observed with naked eyes.