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Unsharpness is the loss of spatial resolution in a radiographic image. There are generally considered to be three types of unsharpness: geometric unsharpness, motion unsharpness and photographic or system unsharpness. [1] Motion unsharpness is caused by movement of the patient, the detector or the source of X-rays, during the exposure. Movement ...
Image relating focal spot size to geometric unsharpness in projectional radiography. [2] Geometric magnification results from the detector being farther away from the X-ray source than the object. In this regard, the source-detector distance or SDD [3] is a measurement of the distance between the generator and the detector.
The object is placed in the neutron beam. Given increased geometric unsharpness from those found with X-ray systems, the object generally needs to be positioned as close to the image recording device as possible.
Effect of an anti-scatter grid on incident beams. In medical imaging, an anti-scatter grid (also known as a Bucky-Potter grid) is a device for limiting the amount of scattered radiation reaching the detector, [1] [2] thereby improving the quality of diagnostic medical x-ray images.
Geometric tomography is a mathematical field that focuses on problems of reconstructing homogeneous (often convex) objects from tomographic data (this might be X-rays, projections, sections, brightness functions, or covariograms). More precisely, according to R.J. Gardner (who introduced the term), "Geometric tomography deals with the retrieval ...
Small-angle X-ray scattering (SAXS) is a small-angle scattering technique by which nanoscale density differences in a sample can be quantified. This means that it can determine nanoparticle size distributions, resolve the size and shape of (monodisperse) macromolecules, determine pore sizes and characteristic distances of partially ordered materials. [1]
The units of the structure-factor amplitude depend on the incident radiation. For X-ray crystallography they are multiples of the unit of scattering by a single electron (2.82 m); for neutron scattering by atomic nuclei the unit of scattering length of m is commonly used.
Geometry of a GISAS experiment. The incident beam strikes the sample under a small angle close to the critical angle of total external x-ray reflection. The intense reflected beam as well as the intense scattering in the incident plane are attenuated by a rod-shaped beam stop.