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Questions tagged [tomography-reconstruction]

Different from 3D-reconstruction in computer vision, tomography-reconstruction (or tomographic reconstruction) is an algorithm-oriented 3D reconstruction given the 2D measurement from the boundary. Different slices are reconstructed normally by back-projection algorithm, yet many other algorithms for different purpose are rapidly developed every year.

The mathematical basis for tomographic imaging was laid down by Johann Radon. It is applied in Computed Tomography to obtain cross-sectional images of patients. This article applies in general to tomographic reconstruction for all kinds of tomography, but some of the terms and physical descriptions refer directly to X-ray computed tomography.

The questions regarding the tomographic imaging and its reconstruction algorithms may use this tag. The topics include but not limit to: Radon transform, back-projection, Fourier transform, boundary condition problems, finite element method (FEM), X-ray computed tomography/Positron emission tomography, iterative algorithms, conjugate gradient methods.

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How to get line rectangle intersection segment?

I want to find weight matrix for Algebraic reconstruction method. For this I have to find the line intersection with grid. I can find direct line intersection with line but I have to store the intersected line segment grid number wise. So suppose if…
Parth Patel
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Finding if binary matrix exists given the row and column sums

How to find out if it is possible to contruct a binary matrix with given row and column sums. Input : The first row of input contains two numbers 1≤m,n≤1000, the number of rows and columns of the matrix. The next row contains m numbers 0≤ri≤n – the…
Sushil
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How to refine some specific surfaces in Avizo?

I m using Avizo to generate a mesh of my microstructure obtained from CT scan in order to launch computations in Abaqus. I can generate interesting surfaces meshes, nonetheless outside mesh is too fine (you can see figure with this question). I am…
user3601754
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Recursive algorithm fails to complete tests in allotted time

I was doing a test that required an algorithm for Binary Tomography. A set of 38 test values are supplied that test correctness, but there is also a time limit of 1 CPU sec to complete all the tests. The problem is as follows: Output “Yes” if there…
Xotic750
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DICOM file with CT and MR tags

A DICOM file (an artificial axial slice) has been generated from both a CT and an MR images. Can the aggregated file contain both CT and MR DICOM tags? E.g. Echo Time (0x18, 0x81) and KVP (0x18,0x60)? I cannot find any information whether one image…
Pavlo Dyban
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How to implement a inverse Iradon Transform to a single projection vector?

My question is the example at inverse Iradon Transform to a single projection vector, why the result of iradon need to be divided by 2? https://www.mathworks.com/help/images/ref/iradon.html. Here is the example at the MathWorks webpage: " The…
En Lu
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Filtered backprojection

I'm working on a school project with python and I have to reconstruct an image using filtered backprojection. I made the image using the following code: image = np.zeros([100, 100]) t = np.linspace(-1, 1, image.shape[0]) xc, yc = np.meshgrid(t,…
Houda Ghallab
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How to segment and calculate specific head CT areas through conventional computer-vision methods?

I am generating material for a computer vision (CV) class and I would like to calculate the area of this highlighted part through conventional CV techniques: So, I have applied Canny to detect edges and a Circle Hough transform trying to find the…
rvimieiro
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Moire pattern shows up in the reconstructed image while using radon and iradon

I used this script to reconstruct an image of the Shepp-Logan phantom. Basically, it just simply used radon to get sinogram and used iradon to transform it back. However, I found that a very obvious moire pattern can be seen when I adjust contrast.…
Chenyang Zhao
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Detecting line artifacts in noisy images

I'm doing image processing on computed tomography projection images. There's a specific type of artifact that results from the processing I'm doing which manifests as a vertical line going through the whole image: I'm currently detecting it by…
Tapio
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Extracting sinograms from tomography projections

my name is Lorenzo and I am a postdoc researcher in Italy. My job is related to tomography imaging using synchrotron radiation. This is a new field for me and I start to face with Matlab to write some code. I am completely new with tomography…
LorenzoM
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Qualitative and Quantitative analysis of filtered back projection / iradon in matlab

I was wondering if anyone encountered this issue. I can reconstruct images from matlab that resembles the original image, however, the actual values are always different. For example, original image have values in the matrix ranging from 0 to 1,…
Tofo
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Reconstruct cartesian image from back-projection Matlab

I'm doing an exercise to reconstruct an CT-scan image from its sinogram (given). From the sinogram, implementing the central slice theorem, I did the 1D FFT (after zero padding) sino_fft = fftshift(fft(fftshift(sinogram))); and recover the…
Shika93
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How would I be able to iterate through this loop so it gives me the sinogram for each column of original image?

I want to create an array of columns for 360 different images for a 256x256 images. From each of those columns, I want to create sinograms in order to stack them up and create a back projection. I am currently stuck at this part: imagestack = [image…
physicsenjoyer38
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How to save ndarray or show anim?

I am using TIGRE (an open source toolbox for reconstruction provided by CERN). The original code was written for python 3.7 and is struggling to run correctly on 3.9. This is the original code and the error it produces. #%% Initialize import…
phoenix156
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