We proposed a novel optical geometry for holographic data storage in which a phase input pattern was involved. The
input phase pattern was derived from an amplitude pattern by iterative Fourier transform algorithm. Two important
parameters of reconstructed images, diffraction efficiency and image quality, were discussed and measured. Our
geometry exhibited uniform holographic recording as well as uniform erasing. Moreover, the loss of light due to
absorption in the input pattern was minimized. The little light loss also ensured a higher diffraction efficiency of the
reconstructed image.
KEYWORDS: Digital holography, Holograms, Image encryption, Holography, 3D image reconstruction, Computer programming, Modulators, Digital imaging, Digital recording, Modulation
We propose a novel optical encryption approach using a lenticular lens array (LLA) as a deterministic phase
modulator and the single-shot digital holographic scheme. In the proposed scheme, the input amplitude image is
encrypted and interferes with the reference wave phase, which is modulated by a LLA, then recorded holographically by
a digital CCD camera to form an encrypted hologram. A decryption key is obtained from the key hologram using
numerical reconstruction. The image is decrypted using a digital holographic approach after which the encrypted
hologram is multiplying the numerical reconstructed key for decryption. The experimental results show that only an
encrypted hologram is needed. Moreover with this approach, the decryption procedure can be rapidly accomplished
using a personal computer, presenting a decrypted image of satisfactory image quality. Finally the selective sensitivity of
the key rotation is also investigated.
We discuss a method for the recording of multiple images in a photorefractive LiNbO3 crystal which needs only a
single object beam without any reference beam. The object beam is modulated by a lenticular lens array sheet to produce
a set of sub-object beams. These beams are angularly separated on the recording plane but are made to overlap by light
scattered light by the photorefractive LiNbO3 crystal. The result is that only a single beam is needed to record multiple
holograms. Experimental results show that four holograms can be stored in a photorefractive LiNbO3:Fe crystal 30 mm
X 30 mm X 1 mm in size at the same time. The proposed method makes it especially simple to produce one-beam
write/read multiple holograms.
In this work, a novel approach for numerical wave-front reconstruction in arbitrary phase step digital holography is
presented. We present a simple and effective approach for digital holography microscopy that can be used for the 3D
reconstruction of micro-structure images. The experimental results demonstrate that only two digital holograms and a
simple estimation are required for the twin-image suppression and numerical reconstruction. The advantages of this
approach are its simplicity, in that only one estimate equation need be applied, and its effectiveness, in that the exact
phase profile of a micro lens array is presented, without blurring due to numerical reconstruction or aberration caused by
the quadratic phase micro objective lens.
KEYWORDS: Digital holography, Holograms, 3D image reconstruction, Holography, 3D metrology, Phase measurement, Spatial frequencies, Charge-coupled devices, Digital recording, Wave propagation
We develop a novel holographic reconstruction method that requires only an off-axis Fresnel digital hologram
without the need for additional phase-retrieval elements in the experimental setup. With this approach we can reconstruct
numerical phase profiles without twin-image blurring, using only an off-axis digital hologram. Furthermore numerical
reconstruction and twin-image suppression can be rapidly accomplished with a personal computer. Not only is twin-
image suppression easier but the constraints characteristic of the conventional phase-shifting digital holographic-based
scheme that employs multiple exposures can be overcome. The experimental results clearly show that complex spatial
frequency information about the object to be measured is not lost during numerical reconstruction and that the profile of
the phase object can be exactly measured and presented.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.