Tomography
Tomography is
In many cases, the production of these images is based on the mathematical procedure
Although
Types of tomography
Some recent advances rely on using simultaneously integrated physical phenomena, e.g. X-rays for both
Discrete tomography and Geometric tomography, on the other hand, are research areas[citation needed] that deal with the reconstruction of objects that are discrete (such as crystals) or homogeneous. They are concerned with reconstruction methods, and as such they are not restricted to any of the particular (experimental) tomography methods listed above.
Synchrotron X-ray tomographic microscopy
A new technique called synchrotron X-ray tomographic microscopy (SRXTM) allows for detailed three-dimensional scanning of fossils.[14][15]
The construction of third-generation synchrotron sources combined with the tremendous improvement of detector technology, data storage and processing capabilities since the 1990s has led to a boost of high-end synchrotron tomography in materials research with a wide range of different applications, e.g. the visualization and quantitative analysis of differently absorbing phases, microporosities, cracks, precipitates or grains in a specimen. Synchrotron radiation is created by accelerating free particles in high vacuum. By the laws of electrodynamics this acceleration leads to the emission of electromagnetic radiation (Jackson, 1975). Linear particle acceleration is one possibility, but apart from the very high electric fields one would need it is more practical to hold the charged particles on a closed trajectory in order to obtain a source of continuous radiation. Magnetic fields are used to force the particles onto the desired orbit and prevent them from flying in a straight line. The radial acceleration associated with the change of direction then generates radiation.[16]
Volume rendering
Volume rendering is a set of techniques used to display a 2D projection of a 3D discretely
To render a 2D projection of the 3D data set, one first needs to define a
For example, a volume may be viewed by extracting isosurfaces (surfaces of equal values) from the volume and rendering them as polygonal meshes or by rendering the volume directly as a block of data. The marching cubes algorithm is a common technique for extracting an isosurface from volume data. Direct volume rendering is a computationally intensive task that may be performed in several ways.
History
Focal plane tomography was developed in the 1930s by the radiologist Alessandro Vallebona, and proved useful in reducing the problem of superimposition of structures in projectional radiography.
In a 1953 article in the medical journal Chest, B. Pollak of the Fort William Sanatorium described the use of planography, another term for tomography.[17]
Focal plane tomography remained the conventional form of tomography until being largely replaced by mainly
See also
- Chemical imaging
- 3D reconstruction
- Discrete tomography
- Geometric tomography
- Geophysical imaging
- Industrial CT scanning
- Johann Radon
- Medical imaging
- MRI compared with CT
- Network tomography
- Nonogram, a type of puzzle based on a discrete model of tomography
- Radon transform
- Tomographic reconstruction
- Multiscale Tomography
- Voxels
References
- ISBN 978-1-84628-723-7.
- PMID 17610815.
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- .
- PMID 29048060.
- .
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- ^ Cramer, A., Hecla, J., Wu, D. et al. Stationary Computed Tomography for Space and other Resource-constrained Environments. Sci Rep 8, 14195 (2018). [1]
- ^ V. B. Neculaes, P. M. Edic, M. Frontera, A. Caiafa, G. Wang and B. De Man, "Multisource X-Ray and CT: Lessons Learned and Future Outlook," in IEEE Access, vol. 2, pp. 1568-1585, 2014, doi: 10.1109/ACCESS.2014.2363949.[2]
- S2CID 122576324.
- S2CID 5476218.
- S2CID 4411929.
- S2CID 243434346.
- ^ Banhart, John, ed. Advanced Tomographic Methods in Materials Research and Engineering. Monographs on the Physics and Chemistry of Materials. Oxford ; New York: Oxford University Press, 2008.
- PMID 13107564. Archived from the originalon 2013-04-14. Retrieved July 10, 2011.
- ^ Littleton, J.T. "Conventional Tomography" (PDF). A History of the Radiological Sciences. American Roentgen Ray Society. Retrieved 29 November 2014.
External links
- Media related to Tomography at Wikimedia Commons
- Image reconstruction algorithms for microtomography