Technique Based On Optics Principle For Image Storage And Reconstruction

:In recent years, the information society is developing rapidly. The fast and secure storage of the high-volume data is more and more important. Image is the most common way of information storage. And how to store and transfer safely becomes our concerned topic. The optical hologram is common, while its storage capacity is limited. For the new method, as the volume holographic, is with the large storage capacity. But its application is restricted by the storage materials and the crosstalk.In this thesis, a technique for high-volume images storage and reconstruction based on the optics principle is presented. Blazed gratings with different groove orientations and groove angles are used to superpose many pretreated gray-scaled images into a single diffractive optical element with the same size, and customized spatial filters are used to selectively recover the corresponding images from the diffraction spots of the superposed images. At the same time optical encryption/decryption method can also be added to the digitized element to enhance the security of the stored data.Both the simulation and experiment have been implemented to justify the proposed scheme in this paper. The simulation shows that as many as198images with a size of512pixels x512pixels can be stored in a diffractive optical element with complex amplitudes of the same size, and the recovered images from the element are discernible with high visual quality. In the experiment, the phase distribution of the superposed images is loaded onto a spatial light modulator (SLM) with a computer. Then a laser beam incident to the SLM is modulated by the phase loaded on the SLM. The laser beam is then Fourier transformed by a convex lens. A pinhole is used to filter the desired diffraction spot of an image in the frequency domain. Then another convex lens is used for image reconstruction. Finally, a CCD camera is used to record the reconstructed images. The experimental results demonstrate that images can be stored in a phase element and reconstructed with high fidelity. The method has advantages such as high-volume data storage, easy implementation, high security, and so on.