Hologramm projektor test11/30/2023 Another method is sampling reconstructed image considering the size of voxel’s area to avoid interference between adjacent voxels, which suffers the loss of spatial resolution and the light efficiency 13, 14. Decreasing coherency of the light source (e.g., LED) is one available approach to mitigate the speckle, but it sacrifices overall depth range and spatial resolution 11, 12. Due to the fundamental limitation, it is challenging to remove the speckle for random phase holography. There have to exist interference between the adjacent voxels, resulting in significant speckle contrast even if a small number of random phasors are summated 10. The finite window size and limited diffraction angle of the SLM cause a single voxel to be imaged with area rather than an ideal point. The speckle noise in holography appears inevitably due to the technical issue of the spatial light modulator (SLM), imaging principle of holography, and statistics of random phasors. Until today, it remains as an unsolved challenge for holography to achieve high-contrast, speckle-free, and true 3D projection simultaneously 9. However, the speckle noise from the random phase severely hampers reconstructed images quality, so that the previous works on true 3D projection are limited to sparse images such as dots or letters, or noisy images 7, 8. A possible approach for breaking the dependency is to make the phase profile of 3D points following the random distribution so that the mutual interference is removed by using the orthogonality of random vectors 7. As disadvantages of the dependency, the 3D reconstruction of smooth phase encoding suffers low axial resolution with a small eyebox and difficulty in supporting parallax.Īlthough holography can reproduce the arbitrary 3D volume from the linear superposition of Fresnel zone plate patterns, if the phase of 3D points is defined to some specific distribution, it is limited to control the complex-valued holographic 3D points independently. Yet, the works restrict the 3D points following the specific smooth phase distribution to avoid speckle, which leads to dependency among the complex-valued 3D points. Recent emerging studies of computer-generated holograms (CGHs) concentrate on visualization of photorealistic scene, including high-contrast and speckle-free reconstruction 5, 6. True 3D holography requires ability to project any 3D volume with high-axial resolution and can control all 3D points independently. Holography has been investigated with lots of attention based on the possibility of three-dimensional (3D) projection in the past decades 1, 2, 3, 4. The realization will open a new path towards the next generation of holography. The proposed method can be adopted in various applications of holography, where we show additional demonstration that realistic true 3D hologram in VR and AR near-eye displays. Our high-quality true 3D holography is experimentally verified by projecting multiple arbitrary dense images simultaneously. ![]() Utilizing the fast operation of binary modulation, the full-color high-framerate holographic video projection is realized while the speckle noise of random phase is overcome by temporal multiplexing. We develop the high-performance binary hologram optimization framework to minimize the binary quantization noise, which provides accurate and high-contrast reconstructions for 2D as well as 3D cases. We adopt the random phase for the true 3D implementation to achieve the maximum axial resolution with fully independent control of the 3D voxels. Here, we propose the practical solution to realize speckle-free, high-contrast, true 3D holography by combining random-phase, temporal multiplexing, binary holography, and binary optimization. However, it has been challenging to implement the true 3D holography with high-reconstruction quality due to the speckle. ![]() True 3D holography requires abilities of arbitrary 3D volume projection with high-axial resolution and independent control of all 3D voxels. Holography is a promising approach to implement the three-dimensional (3D) projection beyond the present two-dimensional technology.
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |