Research On Practical Approach Of Color Computer-generated Rainbow Holography

CGH-based display is a true3D wavefront reconstruction technique, which is theinevitable trend of development of optical holography in the information era. Like theoptical holographic display,3D displays of CGH can completely matches the3D visualcharacteristics of human eyes. CGH can not only encode both amplitude and phase ofoptical wave roundly, but also can reproduce the wavefront of virtual objects. Because theunique advantages and flexibility, CGH-based display is considered as the most potential3D display approach. With the rapid development of computer performance, highresolution image display devices, updateable large-format holographic recording materials,micro-nano fabrication technique and other related technique, the applied research ofCGH-based3D display was become one of the significant subject of3D display at present.Based on literature survey and practice, we have summarized several key issues thatrestricting the progress of CGH-based display. The research on practical method of colorcomputer-generated holography (CCGH) is carried out based on theoretical analysis andexperiment proof.So far, color matching method of digital color image is considered as color matchingmethod of CCGH, which is not rigorous theoretically. There exists great color differencebetween holographic image and digital color image by using this color matching method,which may be still acceptable in some cases because of the color constancy of human eyes.In fact, CCGH as a practical color display method, color matching method with stricttheoretical basis is indispensible. In this thesis, the whole color information transferprocess is fully analyzed based on color matching and transfer theory. The relationshipbetween color quantities of color image and amplitude of three primary object lights is established. Finally, the color matching method is applied on color computer-generatedFresnel holography and rainbow holography. CGH-based display with high color quality isrealized.Based on the relationship between holographic grating and three primary wavelengths,the CCGH encoding method by single wavelength is proposed, which can encode the colorinformation of3D object into hologram by single wavelength. Combined this method andprinciple of two step optical rainbow holography, an algorithm mode of colorcomputer-generated rainbow holography (CCGRH) is designed. Color3D displays of bothvirtual and real-existing object are realized.Based on the characteristic of color rainbow holographic display, the colorreproduction mechanism of CCGRH is analyzed and calculation method of three primarycolor of CCGRH is given. The relationship between color quality of rainbow holographicimage and calculation parameters is discussed. The commonly used sample of colordisplay is selected as object of CCGRH and the color rainbow hologram was calculated.Then, the hologram was fabricated on holographic recording material by a self-made highresolution CGH direct writing system. The color difference between holographic imagesand the samples are evaluated by experiment. This work may provide technique base forhigh quality CCGRH fabrication.The field of view of holographic image is a significant technical index for3D display,which is related to3D display effect. Computer hologram with large field of view is nothard to recent computer. The most challenge work is how to fabricate the hologram withhigh speed and low cost. A practical holographic display technique with large field of viewwas proposed by take full advantages of both CGH and optical holography, which candisplay a holographic image with large field of view by using a much smaller CGH andoptical holography. In this thesis, the relationship between information quantity of CGHand3D display is analyzed and the basic principle of color rainbow holographic displaytechnique based on CGH and optical holography is given. An equivalent CCGH encodingalgorithm is proposed, which can encode object information with large view of field into a small format hologram. Then, the hologram is fabricated on holographic recording materialby a self-made high resolution CGH direct writing system. The object wavefront with largefield of view is reproduced by illuminate the CGH with laser. A hologram with large fieldof view is obtained by using another laser beam to interference with the object wavefront.The theoretical design and experimental results are given.