A Review on Analysis of Fast Generation of Digital Holograms

A Holographic display is based on the phenomenon of diffraction. The display element contains the phase modulating element which when accompanied with coherent light source the image is formed. The projection techniques involved the usage of polarizer to control the optical wavefront. This study was conducted by Edward Buckley [2]. The techniques enclosed covered the improved method for hologram generator, quantization effect on holograms, importance of noise in holographic displays and its reduction. In its implementation part the color holographic projector principle involved the extension to multiple phase levels.
The twin barriers to the realization of real time, high quality holographic display was overcome by defining the new, psychometrically determined measure of image and the quality was matched to human visual perception, the method for displaying face holograms was optimized with the new measure of high quality image reproduction. New metrics that was far more suited to the human perception than the conventional MSE measure. Phase generation method which resulted in perceptual pleasing of video style images was found. The realizations of 2D phase holographic video projection system overcome the twin barriers of the computational complexity of calculating the diffraction patterns and the poor quality of the resultant images.
This shows the system of CGH computation using CUDA. Here the experiment through parallel processing had performed.

RESULT AND DISCUSSION
The CGH computation was done in [3] .the parameters were chosen as –
The size of a 3D object is 200*200 pixels, 8 bit. The sources of light are 6982.The sample image is Stanford Bunny.
And we made a hologram resolution, which is 1024 * 1024 pixels. The reference wave length (λ) is 633mm, reconstruction distance is 100nm. The pixel-pitch (p) is 10.4um x10.4um. Figure 2 shows the images used in this experiment.

Figure 2-(a) is a 3D object.

Figure 2-(b) is a reconstruction image by using a computation on CPU-based.
Figure 2-(c) reconstruction image on GPU- based.
EXPERIMENTAL
First the hologram is generated from a digital system. It is termed as Recording of hologram , by the use of 3D object model, in this case Stanford bunny is used.
The CGH computation is expressed as(1).


CONCLUSION
The stream processor of graphics processing units enhanced the speed of generation of digital holograms. The collected threads altogether act as a pixel of digital hologram thus increased overall computation time by 64 times than CPU based. All this was achieved because of simultaneous computing in GPU based generation of holograms.