What is Tomography: Definition and 23 Discussions

Tomography is imaging by sections or sectioning through the use of any kind of penetrating wave. The method is used in radiology, archaeology, biology, atmospheric science, geophysics, oceanography, plasma physics, materials science, astrophysics, quantum information, and other areas of science. The word tomography is derived from Ancient Greek τόμος tomos, "slice, section" and γράφω graphō, "to write" or, in this context as well, " to describe." A device used in tomography is called a tomograph, while the image produced is a tomogram.
In many cases, the production of these images is based on the mathematical procedure tomographic reconstruction, such as X-ray computed tomography technically being produced from multiple projectional radiographs. Many different reconstruction algorithms exist. Most algorithms fall into one of two categories: filtered back projection (FBP) and iterative reconstruction (IR). These procedures give inexact results: they represent a compromise between accuracy and computation time required. FBP demands fewer computational resources, while IR generally produces fewer artifacts (errors in the reconstruction) at a higher computing cost.Although MRI and ultrasound are transmission methods, they typically do not require movement of the transmitter to acquire data from different directions. In MRI, both projections and higher spatial harmonics are sampled by applying spatially-varying magnetic fields; no moving parts are necessary to generate an image. On the other hand, since ultrasound uses time-of-flight to spatially encode the received signal, it is not strictly a tomographic method and does not require multiple acquisitions at all.

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  1. T

    I How can tomographic image resolution be obtained using wifi sensing and imaging?

    hello i would like to ask how to obtain tomographic image resolutions from wifi sensing and imaging using signals processing. thanks very much.
  2. red65

    I Why do we use low-coherence light in Optical Coherence Tomography?

    Hello , I study the principles of optical coherence tomography, where we emit light and by the refraction that we detect we reconstruct and image, but I don't understand why we use low coherence light , if i want to measure the refracted light i would prefer to have coherent light so that the...
  3. racerunner

    B Muon Tomography Evidence for Special Relativity?

    Muons are a popular way to provide evidence for Special Relativity. But, does Muon Tomography provide evidence for SR? Can you calibrate your muon detectors without reference to SR? Is there any need to refer to SR when interpreting the data? I tutored a high school student who argued the...
  4. Jamister

    A Homodyne detection quantum state tomography

    In balanced homodyne detection, it is claimed that one can do state tomography. I understand most of the derivation except one part. Here is a figure describing homodyne detection. the operator that is being measured is $$ R=N_{1}-N_{2}=a^{\dagger} b+b^{\dagger} a $$. taking the mode b to be...
  5. A. Neumaier

    I Quantum mechanics via quantum tomography

    I just finished a new paper, A. Neumaier, Quantum mechanics via quantum tomography, arXiv:2110.05294. (later renamed to) A. Neumaier, Quantum tomography explains quantum mechanics, arXiv:2110.05294. Abstract: Starting from first principles inspired by quantum tomography rather than Born's...
  6. I

    I Question about No-Cloning Theorem and State Tomography

    Hi, I have a question, or am looking for clarification, about the no-cloning theorem and state tomography. My understanding is that the theorem states one cannot make an exact copy of a quantum state. I was also reading about state state tomography where it was said* 'On the other hand, the...
  7. J

    A Quantum tomography: Where does the magic happen?

    My question is: How does this happen? Less measurements than 4^n-1 means that literally we don't have enough information to label the state. How can the neural network overcome this lack of information?
  8. J

    A Restricted Boltzmann machine for Quantum state tomography

    I'm struggling with my Final Degree Project. I would like to perform a quantum simulation and perform quantum tomography for a single-qubit using a resrticted Boltzmann machine. In order to do so I'm trying to follow the recipe in the paper "Neural Network quantum state tomography, Giacomo...
  9. Amartansh

    Diffraction tomography, inverse scattering

    What are some good books which covers topics like diffraction tomography, inverse scattering, RF imaging and Fourier optics?
  10. Amartansh

    Difference between "Inverse Scattering" and "Diffraction tomography"?

    I saw there are two types of methods for RF imaging, Inverse Scattering" and "Diffraction tomography. What are the differences between them?
  11. Amartansh

    Rayleigh limit in inverse scattering imaging

    I was reading that in inverse scattering approach, we divide the region of interest into discrete grids and size of each grid should be much smaller than the incident wavelength (usually smaller than one-tenth of wavelength). By this logic, theoretically, I can use inverse electromagnetic...
  12. riodice

    Question about PET scans (Positron emission tomography)

    I understand that a PET scan will produce Positrons which will come into contact with an electron and produce Gamma rays in the area where there is a high uptake of sugar (assume glucose). In this process of annihilating an electron, some poor atom will lose an electron which I assume would...
  13. DariusP

    How Does Optical Coherence Tomography Work to Image Different Tissue Layers?

    Anyone familiar with how this device works? I'm having trouble understanding how different layers of tissue can be imaged using interference. I am sort of familiar with michaelson interferometer and what is low coherence light if that helps.
  14. 1oldman2

    Exploring Earth's Interior with Seismic Tomography and Weather Bombs

    This could open a new frontier on seismic study of the Earth's interior. http://www.bbc.com/news/science-environment-37177575 From, http://science.sciencemag.org/content/353/6302/919 Seismic tomography is like an x-ray of Earth's interior, except that it uses earthquakes for the illumination...
  15. klotza

    Insights The Basics of Positron Emission Tomography (PET) - Comments

    klotza submitted a new PF Insights post The Basics of Positron Emission Tomography (PET) Continue reading the Original PF Insights Post.
  16. Alejandro Golob

    Industrial Computed Tomography: A Data Analyst's Perspective

    Good day all, I've been a lurker for years but for some reason never joined despite often finding helpful advice and explanations on the forums. Glad to finally be joining and hoping to provide some helpful insights to others in the admittedly few areas where I have the facility. And of...
  17. J

    Electrical resistivity tomography

    Hi all, I have been searching the internet for explanations on the method of ERT, but they are in general extremely complex and contain very specific vocab that I'm not understanding. Would somebody care to explain to me the method of ERT in language that an A Level student can understand...
  18. Pythagorean

    Cell tomography interpretation

    how would you learn to interpret the components of something like this? Am i seeing the whole cross-sectional area of a cell? http://learn.genetics.utah.edu/content/begin/cells/membranes/images/tomography.jpg (insulin-producing pancreas cell...
  19. J

    Attosecond Tomography and Elephants

    I just read a paper about attosecond science and wavefunction tomography. This allows for "pictures" to be taken of the wavefunction of a bound electron including spatial and phase information. Is this "picture" a picture of a single electron from a certain particles wavefunction or is it...
  20. P

    What are the phase factors for the atoms in this quantum state?

    Homework Statement Assume there is a source of some pre-selected atoms. When measuring atoms of that source in a Stern-Gerlach, you find the following probabilities for a spin-up result: x-direction 5/6 y-direction 5/6 z-direction 1/3 Which state would you ascribe to the source...
  21. E

    How Does Fourier Domain OCT Extend Interference Beyond Coherence Length?

    Hello, I don't know if anyone is familiar with OCT, but my question is rather specific and a well explained answer is in my opinion nowhere to be found ... In OCT, a low coherent light source is used in a simple Michelson interferometer setup. One beam (reference beam) is sent onto a...
  22. D

    State Tomography: Least Pairs Needed?

    I don't know where this question belongs: Given many pairs of \left|\Psi\right> and U\left|\Psi\right>, for some unitary U, is it possible to identify U without completely determining the two states independently? I mean what is the least possible number of pairs needed (to be x% certain), and...