Browsing College of Engineering & Architecture by Subject "Imaging systems"

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Browsing College of Engineering & Architecture by Subject "Imaging systems"

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Comparison of Laplacian differential reconstruction of inline holograms recorded at two different wavelengths and distances

Ryle, James P. ; Li, Dayan ; Sheridan, John T. (Optical Society of America, 2010-04-11)

We record two holograms using two different illuminating wavelengths. Subtracting these holograms, the resulting reconstruction is an approximation to the second order Laplacian differentiation of the object wave.
Controlling speckle using lenses and free space

Kelly, Damien P. ; Ward, Jennifer E. ; Gopinathan, Unnikrishnan ; Sheridan, John T. (Optical Society of America, 2007-12-01)

The correlation properties of speckle ﬁelds are studied for general paraxial systems. The previous studies on lateral and longitudinal speckle size for the case of free-space propagation (Fresnel transform) are generalized ...
Dual wavelength digital holographic Laplacian reconstruction

Ryle, James P. ; Li, Dayan ; Sheridan, John T. (Optical Society of America, 2010-09-15)

Access to the spatial derivatives of an optical wave field can be used to enhance edge detection, focusing, and holographic imaging. It was recently shown that, by using digital holographic techniques, the Laplacian of an ...
Fundamental diffraction limitations in a paraxial 4-f imaging system with coherent and incoherent illumination

Kelly, Damien P. ; Sheridan, John T. ; Rhodes, William T. (Optical Society of America, 2007-07-01)

In the usual model of an imaging system, only the effects of the aperture stop are considered in determining diffraction-limited system performance. In fact, diffraction at other stops—those associated with different lens ...
Holography : an interpretation from the phase-space point of view

Situ, Guohai ; Sheridan, John T. (Optical Society of America, 2007-12-15)

The formation of holograms is interpreted as the consequence of the bilinearity of the ambiguity function. Reconstruction can then be regarded as the manipulation of the ambiguity function. Specifically, we show that in ...
Lucky imaging and aperture synthesis with low-redundancy apertures

Ward, Jennifer E. ; Rhodes, William T. ; Sheridan, John T. (Optical Society of America, 2009-01-01)

Lucky imaging, used with some success in astronomical and even horizontal-path imaging, relies on fleeting conditions of the atmosphere that allow momentary improvements in image quality, at least in portions of an image. ...
Reliability of crack detection for baseline condition assessments

Laefer, Debra F. ; Gannon, Jane ; Deely, Elaine (American Society of Civil Engineering (ASCE), 2010-06)

Despite billions of dollars of annual exposure from claims and litigation related to construction-induced damage, there are no quantitatively based, agreed upon standards or procedures as to what constitutes due diligence ...
Three-dimensional speckle size in generalized optical systems with limiting apertures

Ward, Jennifer E. ; Kelly, Damien P. ; Sheridan, John T. (Optical Society of America, 2009-08-01)

Correlation properties of speckle ﬁelds at the output of quadratic phase systems with hard square and circular apertures are examined. Using the linear canonical transform and ABCD ray matrix techniques to describe these ...