Share Email Print

Optical Engineering

Digital Fresnel field encryption for three-dimensional information security
Format Member Price Non-Member Price
PDF $20.00 $25.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

The complex Fresnel field that contains three-dimensional (3-D) information about an object can be retrieved from an optically generated and electronically detected single off-axis Fresnel hologram of a 3-D object. The retrieved complex Fresnel field gives the appearance of a noise-like distribution. This is primarily due to the scattering nature of the object and the resulting speckle noise, which is a salient trait of the reconstruction process of a hologram. We describe a possible method for securing holographic information by digital encoding of the Fresnel field. A single random-phase Fourier plane encoding is carried out with an assumption that the noisy nature of the complex field may be equivalent to the primary random mask-bonded field, as in the case of conventional double random-phase Fourier plane encoding. The analogy between the decryption process and the numerical reconstruction of the hologram leads to a single-step reconstruction of the complex object field from the encrypted Fresnel field, thus saving computational power. The use of a single off-axis hologram is helpful in zero-order and twin-image free reconstruction. The algorithm is explained with experimental results to support the proof of the concept.

Paper Details

Date Published: 1 April 2007
PDF: 8 pages
Opt. Eng. 46(4) 045801 doi: 10.1117/1.2727377
Published in: Optical Engineering Volume 46, Issue 4
Show Author Affiliations
Anith Nelleri, Indian Institute of Technology Delhi (India)
Joby Joseph, Indian Institute of Technology Delhi (India)
Kehar Singh, Indian Institute of Technology Delhi (India)

© SPIE. Terms of Use
Back to Top