Topic
Fresnel zone
About: Fresnel zone is a research topic. Over the lifetime, 2337 publications have been published within this topic receiving 37650 citations.
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Patent•
30 Aug 2002
TL;DR: In this paper, a Fresnel lens sheet is formed with a number of prism groups extending on a straight line or to an arcuate form on its light incident surface, in which total reflecting surfaces for totally reflecting incident light and emitting the light to an observer side are formed on the individual prisms constituting the prism groups.
Abstract: PROBLEM TO BE SOLVED: To provide a Fresnel lens sheet without causing stray light itself. SOLUTION: The Fresnel lens sheet is formed with a number of prism groups extending on a straight line or to an arcuate form on its light incident surface, in which total reflecting surfaces for totally reflecting incident light and emitting the light to an observer side are formed on the individual prisms constituting the prism groups. The heights of the prisms in the respective regions of the light incident surfaces of the Fresnel lens sheet are made higher than the heights of the prisms in the other regions. COPYRIGHT: (C)2004,JPO
12 citations
TL;DR: In this article, a conceptual model suggests that seismic amplitude variations with offset (AVO), azimuth (AVAz), and frequency (spectral decomposition) were physically related to textural roughness, textural anisotropy, and textural scale of the Fresnel zone, respectively.
Abstract: The 3D reflection seismic response is associated with a zone (the Fresnel zone), rather than with a single point used in the idealized 1D convolution model. Unlike a point of incidence, the Fresnel zone is complicated by its textural characters that are defined by the dip and azimuth of microreflectors in the zone. The Fresnel-zone texture makes seismic amplitude interpretation more complicated than previously documented. A conceptual model suggests that seismic amplitude variations with offset (AVO), azimuth (AVAz), and frequency (spectral decomposition) were physically related to textural roughness, textural anisotropy, and textural scale of the Fresnel zone, respectively. Textural roughness is defined by the dip deviation of microreflectors and contributes to the AVO intercept and gradient. Textural anisotropy is defined by the degree of the preferred orientation of the microreflectors and directly affects the AVAz signature. Textural scale is defined by the spacing of the microreflectors and c...
12 citations
TL;DR: This unification procedure is employed in a second stage in the design of a novel hybrid (diffractive-refractive) optical setup that provides, in a sequential way, nearly wavelength-independent Fresnel diffraction patterns in the irradiance of the object transmittance.
Abstract: We recognize that one can adapt any dispersion-compensated broadband optical Fourier transformer to achieve wavelength compensation in the Fresnel diffraction region just by inserting a diffractive lens at the input plane and vice versa. This unification procedure is employed in a second stage in the design of a novel hybrid (diffractive–refractive) optical setup that provides, in a sequential way, nearly wavelength-independent Fresnel diffraction patterns in the irradiance of the object transmittance.
12 citations
TL;DR: A two-step autoradiographic imaging technique utilizing a coded aperture in the form of a lead on-axis Fresnel zone plate is presented, and several isotope-filled plastic phantoms were successfully imaged.
Abstract: A two-step autoradiographic imaging technique utilizing a coded aperture in the form of a lead on-axis Fresnel zone plate is presented. Several isotope-filled plastic phantoms were successfully imaged. These images contain tomographic information of very good quality. The advantages and disadvantages of the technique are discussed.
12 citations
TL;DR: Based on Kuo and Dai's vectorial wave field extrapolation equations, the authors derived new Kirchhoff migration equations by introducing unit vectors which represent the ray directions at the imaging points of the reflected P- and PS converted-waves.
Abstract: Based on Kuo and Dai’s vectorial wave-field extrapolation equations, we derive new Kirchhoff migration equations by introducing unit vectors which represent the ray directions at the imaging points of the reflected P- and PS converted-waves. Furthermore, using the slope of the events on shot records and a ray racing procedure, mirror-image reflection points are found and the reflection data are smeared along the Fresnel zone. The migration method proposed in this paper solves two troublesome imaging problems caused by limited receiving aperture and migration artifacts resulting from wave propagation at the velocities of non original wave type. The migration method is applied successfully with model data, demonstrating that the new method is effective and correct.
12 citations