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.
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.
In this work we present a single exposure method for recording multiple holograms in reflection holography. In this
novel method, the input pattern is a segmented image composed of alternating slices of several original images and
modulated by a lenticular lens array sheet. A set of object beams can be produced simultaneously, which are angularly
separated on the recording plane and overlap one reference beam at the same time. Therefore, only one exposure is
needed for holographic recording multiple holograms. Experimental results show that a lenticular lens array sheet placed
as a modulator in the path of the object beam provides a simple yet effective ingredient of creating multiple images for
single-exposure holography. The proposed method is especially useful for one-step write/read multiple holograms and
for stereoscopic display applications.
We propose a novel optical holographic encrypted data storage scheme based on phase encoding multiplexed scheme. In the proposed data storage scheme, patterns of encrypted images are stored holographically in a photorefractive LiNbO3:Fe crystal by using lenticular lens array (LLA) sheet phase-encoded multiplexing.
Experimental results show that rotating a LLA placed as a phase modulator in the path of the reference beam provides a simple yet effective method of increasing the holographic storage capabilities of the crystal. Combining this rotational multiplexing with two-axis tilting multiplexing offers not only further data storage
capabilities but also data encryption possibilities.
We built the Dual Beam Mode of the LDA (Laser Doppler Anemometry) frame, set the photodetector at the same side with light source which collect the scattering light of blood cell. It's proper to reduce LDA optical path and convenient for our designing module. The concentration of chicken blood in this study is about 1% and we measured the relations actually between flood velocity and the angle of beams cross on particles, temperature, and the diameter of aqueduct. We found better results while the cross angle was less than 38.8 degree, diameter of aqueduct was 6 mm, and temperature of blood was set to 36 . These parameters can also provide important basis for the LDA module kit that we are designing.
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