The Study Of Color Computer-generated Holography Based On DMD

With the development of information technology, how to better access and display 3D information has become the hotspot research. Theoretically, computer generated hologram(CGH) uses spatial distribution function of three-dimensional objects to get the hologram calculation of 3D objects without real world objects, then the object can be reconstructed by using optoelectronic reconstruction method. So it is considered to be a very effective way of three-dimensional image display in the future. Due to the advantages of its fast response and high energy efficiency, digital micromirror device(DMD) is widely used in holographic projection system.In this paper, by using DMD as the optoelectronic reconstruction unit of color CGH, the research work of color holographic reconstruction technique is carried out. The main research contents include the following aspects:1. According to the theoretical model of DMD, through a detailed derivation of the diffracted light field function, the distribution of a diffracted light field can be got and the distribution results of diffractive optical field were analyzed and discussed.2. According to the different diffraction characteristics of the R, G, B three color components, the way of eliminating the chromatic aberration of magnification based on a single color component of the colorful image was proposed. Then two kinds of solutions on how to remove the transverse chromatic aberration are put forward.(1)The scheme of spot synthesis: The strongest diffraction spots are coincided and the multicolor composite lighting is obtained by adjusting the incident angles of the three-color lasers.(2)The scheme of regional adjustment: The center of the reconstructed image of each color component coincides in the certain area by adjusting the positions of the three-color components in the hologram and the incident angles of the three-color lasers.3. To solve the two kinds of chromatic aberrations, a lensless color holographic reproduction system which uses single DMD as the core was built. The scheme of spot synthesis based on time division multiplexing and the scheme of regional adjustment based on space division multiplexing. Optical experiments based on the two kinds of programs are implemented. The spot synthesis experiment enlarges the bearing area of the hologram maximally and realizes better color hologram image under existing conditions. The regional adjustment experiment allows color objects to be reconstructed by single DMD without timing control device.