Search results for "Distortion"
showing 10 items of 309 documents
Arbitrary Waveform Generator Based on All-Incoherent Pulse Shaping
2006
An all-incoherent technique for the generation of arbitrary electromagnetic intensity profiles is presented. It is based on spectral filtering of a broadband continuous-wave light source so that the filtered spectral density function (SDF) becomes the user-defined waveform. After large temporal modulation and subsequent distortion in a first-order dispersive medium, the incoherent mapping of the filtered SDF to the time domain occurs. Finally, optical-to-electrical conversion in a fast photodiode allows the optical intensity to be mapped into the electrical domain
Achromatic Fourier transforming properties of a separated diffractive lens doublet: Theory and experiment
1998
The strong chromatic distortion associated with diffractive optical elements is fully exploited to achieve an achromatic optical Fourier transformation under broadband point-source illumination by means of an air-spaced diffractive lens doublet. An analysis of the system is carried out by use of the Fresnel diffraction theory, and the residual secondary spectrum (both axial and transversal) is evaluated. We recognize that the proposed optical architecture allows us to tune the scale factor of the achromatic Fraunhofer diffraction pattern of the input by simply moving the diffracting screen along the optical axis of the system. The performance of our proposed optical setup is verified by sev…
Optically-undistorted digital holographic microscopy for quantitative phase-contrast imaging
2011
We propose a telecentric architecture for circumventing, by a pure-optical method, the residual phase distortion inherent to standard configuration of digital holographic microscopy (DHM). With this proposal there is no need for computer compensation of the parabolic phase during the phase map recovering procedure. Futhermore, in off-axis configuration, the spatial frequency useful domain is enlarged. The validity of the method is demonstrated by performing quantitative measurements of depth differences
Broadband space-variant Fresnel processor
2002
We present a radically new class of optical setup working with white-light illumination, namely, a chromatically compensated processor operating in the Fresnel domain. The optical configuration is a hybrid (diffractive-refractive) three-lens system that exhibits an intermediate achromatic Fresnel plane and an output image plane without chromatic distortion. As a first application of this optical arrangement we develop a parallel space-variant color pattern-recognition experiment with white light.
BEF Analogy for Concrete Box Girder Analysis of Bridges
2010
<p>Box girder, due to its high torsional stiffness, is very appropriate for railway and highway long- medium span bridges. This type of cross section, subjected to transversely non-uniform loads, present warping and distortion phenomena. Accurate but time-consuming numerical procedures are available for determination of further strains and stresses caused by cross-section deformation. In this paper warping and distortion of box girders is evaluated through BEF analogy, by writing a 4th order differential equation. The problem is solved for practical cases of box girders by considering internal diaphragms stiffness. Graphs are supplied to designers and main design parameters affecting …
Determination of projection geometry from quantitative assessment of the distortion of spherical references in single-view projection radiography
2004
A method is introduced, inferring the three-dimensional (3-D) location from the 2-D radiographic shadow of an opaque spherical reference body of known radius by considering its elliptical distortion, the 2-D shadow location and a known source-to-receptor distance. Three noncollinear spheres fixed to a rigid object constitute all possible degrees of freedom, i.e., the entire 3-D imaging geometry. The method may be used (a) to determine the 3-D imaging geometry from a single 2-D view and (b) to correct for foreshortening of object distances coplanar with the plane defined by the sphere triplet. Apart from the mathematical background the article describes a small feasibility experiment, perfor…
Applying System Dynamics Modeling To Foster a Cause-and-Effect Perspective in Dealing with Behavioral Distortions Associated with a City’s Performanc…
2015
This paper aims to show how applying system dynamics methodology to performance management can provide a powerful modeling perspective enabling public sector organizations to prevent, detect, and counteract behavioral distortions associated with performance measurement. A dynamic performance management approach is able to support performance management system designers in outlining and implementing a consistent set of measures that can allow public sector decision-makers to pursue sustainable organizational learning and development. This perspective implies a major shift from a static to a dynamic picture of organizational processes and results. It means framing delays between causes and ef…
On BLD-mappings with small distortion
2021
We show that every $$L$$ -BLD-mapping in a domain of $$\mathbb {R}^{n}$$ is a local homeomorphism if $$L < \sqrt{2}$$ or $$K_I(f) < 2$$ . These bounds are sharp as shown by a winding map.
Sobolev Extension on Lp-quasidisks
2021
AbstractIn this paper, we study the Sobolev extension property of Lp-quasidisks which are the generalizations of classical quasidisks. After that, we also find some applications of this property.
Distortion of the virtual photon cloud due to a static electric field
1988
The structure of the virtual transverse-photon cloud surrounding a ground-state hydrogen atom is considered in the presence of a uniform static electric field, which is capable of polarizing the atom. It is shown that this virtual cloud is distorted with respect to the spherically symmetric shape which is obtained when no static electric field is present. The distortion is carried by new components of the cloud, arising from the contributions of magnetic-dipole and electric-quadrupole virtual photons. These new contributions are shown to possess an overall cylindrical symmetry around the direction of the static field, and to be present also at large distances from the atom. The possibility …