Sarepy’s documentation¶

Welcome to Sarepy’s documentation about removing ring artifacts in tomography. This documentation is not only to explain functions used in the Sarepy package but also to cover the following topics:
Causes of ring artifacts.
Classification of ring artifacts.
How ring removal methods work; pros and cons of each method; how to use them efficiently; and how to improve them.
Applications of the methods.
Author: Nghia Vo, NSLS-II, Brookhaven National Lab, US; Diamond Light Source, UK.
Keywords: Ring artifact removal, Tomography, Stripe artifacts, Tutorial.
Important notice¶
Starting 05/2021, methods in Sarepy have been integrated and developed further in the Algotom package, https://github.com/algotom/algotom . Algotom (Ref. [3]) is a complete package for processing tomographic data. It is installable using Conda and Pip. Demonstrations of using different removal methods on challenging sinograms are shown here: https://algotom.readthedocs.io/en/latest/toc/section4/section4_4.html
Table of Contents¶
- 1. Causes of ring artifacts
- 2. Classification of stripe artifact types
- 3. Methods for removing ring artifacts
- 3.1. Preprocessing methods
- 3.1.1. Equalization-based methods for removing partial and full stripe artifacts
- 3.1.2. Prior methods for removing stripe artifacts
- 3.1.3. Method for locating stripe artifacts
- 3.1.4. Method for removing large stripes
- 3.1.5. Method for removing unresponsive and fluctuating stripes
- 3.1.6. Combinations of methods
- 3.2. Postprocessing methods
- 3.3. Common side effects of ring artifact removal methods
- 3.1. Preprocessing methods
- 4. Applications
- 5. Improvements and new features available in Algotom
- 5.1. Improvements
- 5.2. Tools for designing ring removal methods
- 5.2.1. Back-and-forth sorting
- 5.2.2. Separation of frequency components
- 5.2.3. Polynomial fitting along an axis
- 5.2.4. Wavelet decomposition and reconstruction
- 5.2.5. Stripe interpolation
- 5.2.6. Transformation between Cartesian and polar coordinate system
- 5.2.7. Transformation between sinogram space and reconstruction space
References¶
Nghia T. Vo, Robert C. Atwood, and Michael Drakopoulos, “Superior techniques for eliminating ring artifacts in X-ray micro-tomography,” Optics Express 26, 28396-28412 (2018); https://doi.org/10.1364/OE.26.028396.
Nghia T. Vo, Robert C. Atwood, and Michael Drakopoulos, “Preprocessing techniques for removing artifacts in synchrotron-based tomographic images,” Proc. SPIE 11113, Developments in X-Ray Tomography XII, 111131I (10 September 2019); https://doi.org/10.1117/12.2530324.
Nghia T. Vo, Robert C. Atwood, Michael Drakopoulos, and Thomas Connolley, “Data processing methods and data acquisition for samples larger than the field of view in parallel-beam tomography,” Opt. Express 29, 17849-17874 (2021); https://doi.org/10.1364/OE.418448.