The detection of amplitude distribution of the conventional time average holography is realized through the
reconstructed image intensity, however, no satisfactory results can be often obtained because there are many noise
influences such as speckle noise. As there are only two values for the phase of the first kind of zero-order Bessel
function, namely 0 and μ, we can determine the amplitude distribution through the reconstructed field phase. And this
method is better than the conventional, but it takes a longer time. This paper presents a new method that through
introducing the shearing principle to vibration measurement of time average digital holograph, we can detect the
amplitude distribution rapidly by directly using the shearing interferogram to find out the phase stepping region, and this
method need no phase unwrapping operation. Simulation computation and experiment results show that the time new
method need for vibration measurement is shorter than that of reconstructed field phase, and the measurement effect is
better than that of reconstructed image intensity.
KEYWORDS: Holograms, 3D image reconstruction, Digital holography, Image quality, Digital micromirror devices, Holography, Digital imaging, Image enhancement, Diffraction, Digital recording
A signification characteristic is found by analyzing lensless Fourier digital hologram and synthetic aperture holography
that is the imaging surface of reconstructed image of lensless Fourier digital hologram just is focus plane of positive lens
that is unrelated with wavelength of restruction and recording and their ratio. The nature is propitious to resolve the
problem of DMD display caused by unstable holographic imaging surface. Zero order diffraction image is focused on
nearby center of focal surface and imaging zone is rapidly contracted that largely improved quality of reconstructed
image. Meanwhile, position of holographic reconstructed image is not to be altered when parallel moving lensless
Fourier digital holography on the holographic image plane that is easier to improve hologram duty cycle, DMD
availability and quality of reconstructed image with theory of synthetic aperture that attained by single illumination.
According to this analysis, a new method is proposed that combine lensless Fourier digital holography with synthetic
aperture that could improve quality of DMD reconstructed image. We provided laboratory results and verified all theory
analysis that totally proved the method is available and feasible.
Phase unwrapping is an important content of digital holography, which gets continual and real phase
from wrapped phase. The least-squares phase unwrapping is a fast and effective method. But for wrapped phases
with complicated variation and much noise, the unwrapped phase got by least-squares method will produce errors.
In this paper iterative unwrapping of phase difference is combined with least-squares unwrapping to eliminate the
errors. This method is used in digital holography to unwrap phases with complicated variation. The phase variation
of object wave through a polymethyl methacrylate (PMMA) specimen with a hole under uniform tensile force is
measured by holography. The phase is unwrapped by phase unwrapping based on least-squares and iteration. The
cosine patterns of unwrapped phase and wrapped phase are consistent. Which means this method is correct and can
be used to unwrap phases with complicated variation and much noise.
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.