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.
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...
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...
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...
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...
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...
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?
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...
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...
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...
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.
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...
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...
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...
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...
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...
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...
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...
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...