نتایج جستجو برای: pinhole
تعداد نتایج: 1631 فیلتر نتایج به سال:
We present a simple reconstruction algorithm for three-dimensional (3D) incoherent source distributions imaged by a laterally scanned pinhole camera. We consider digital sampling of multiple pinhole images for 3D reconstruction and implement an experimental demonstration with lateral resolution of 2x10(-3) rad and longitudinal resolution of approximately 0.14z(2) m , where z is the object-to-pi...
The performances of a compact infrared optical system using advanced pinhole optics for wide field applications are given. This concept is adapted from the classical Tisse design in order to fit with infrared issues. Despite a low light gathering efficiency and a low resolution in comparison with classical lenses, pinhole imagery provides a long depth of field and a wide angular field of view. ...
The wireless channel of backscatter radio systems is a two-way pinhole channel, created by the concatenation of two standard wireless channels. Pinhole channels cause higher attenuation and deeper fades than common wireless channels. Passive ultra-high frequency radio-frequency identification (UHF RFID) is such a backscatter radio system, with the backscattering tag acting as pinhole. While the...
A resolution and viewing-angle enhanced integral imaging system using electrically movable pinhole array is proposed. A pinhole array on liquid crystal is adopted as dynamic pinhole array in integral imaging. The location of the pinhole array is controlled electrically. The pinhole array is expected to be moved fast enough to make an after-image effect, and the corresponding elemental images ar...
The focusing capabilities of a pinhole zone plate lens are presented and compared with those of a conventional Fresnel zone plate lens. The focusing properties are examined both experimentally and numerically. The results confirm that a pinhole zone plate lens can be an alternative to a Fresnel lens. A smooth filtering effect is created in pinhole zone plate lenses, giving rise to a reduction o...
PURPOSE To quantify the visual functional changes caused by pinhole glasses. METHODS Healthy subjects underwent ophthalmic examinations including uncorrected distance visual acuity (UDVA) and corrected near visual acuity (CNVA), pupil size, depth of focus (DOF), accommodative amplitude, visual field (VF) test, contrast sensitivity (CS), and stereopsis. Subjects underwent the same examinations...
Objectives This retrospective study evaluated whether the use of additional anterior 99mTc-sestamibi/123I pinhole imaging improves the outcome of 99mTc-sestamibi/123I subtraction SPECT/CT in parathyroid scintigraphy (PS). Materials and Methods PS using simultaneous dual-isotope subtraction methods and an acquisition protocol combining SPECT/CT and planar pinhole imaging was performed for 175 ...
UNLABELLED This study was undertaken to determine the effects of collimators on the accuracy of preoperative sestamibi parathyroid imaging of the neck. METHODS Forty-nine patients with primary hyperparathyroidism underwent preoperative (99m)Tc-sestamibi parathyroid imaging. The protocol included early and late pinhole and parallel-hole imaging. One experienced nuclear physician, without knowl...
The imaging of distributed sources with near-field coded aperture (CA) remains extremely challenging and is broadly considered unsuitable for single-photon emission computerized tomography (SPECT). This study proposes a novel CA SPECT reconstruction approach and evaluates the feasibilities of imaging and reconstructing distributed hot sources and cold lesions using near-field CA collimation and...
UNLABELLED (99m)Tc-sestamibi dual-phase scintigraphy is currently established for parathyroid localization. However, the imaging technique is not standardized, and the role of the pinhole collimator, especially, is not fully recognized in the imaging protocol. The aim of this study was to check whether the use of a pinhole collimator in parathyroid scintigraphy would enhance lesion detectabilit...
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