Medical Image Computing and Signal Processing Lab

• Contact Details :
  • Email Address : ajin.joy@iiitmk.ac.in, ajinjoy@outlook.com
  • Phone no. (M) : +91-9745231441
  
  
• Research Focus : Compressed sensing in parallel MRI

Magnetic resonance imaging (MRI) is one of the most popular non-invasive imaging techniques used to look inside the human body and visually represent the physiology of various organs and tissues. One of its particularly notable features is the lack of ionizing radiations involved. However, a relatively high scanning time puts it at a disadvantage. The demand for accelerated imaging is often met by restricting the amount of data collected from the scanner. Missing data would then be estimated offline to reconstruct an artifact-free image. In my thesis, a new approach to MRI reconstruction using robust non-linear (NL) diffusion based compressed sensing (CS) is introduced and investigated in detail.

In the primary phase of the work, a Perona-Malik (PM) diffusion based sparse approximation algorithm is developed as an alternative to TV to address its high sensitivity to regularization parameter. In the succeeding part, a mixed-order diffusion algorithm is developed that can prevent the formation of both staircase and speckle effects during reconstruction. In the final part of the work, a directionality guided diffusion reconstruction algorithm is developed that enables a better preservation of the complex structural details in the image by adapting the direction of diffusion to local variations in the directionality of edges and employing a precise diffusion in the local regions of the image on a sub-pixel level.

• Ajin Joy, Mathews Jacob and Joseph Suresh Paul. "Compressed sensing MRI using an interpolation-free non-linear diffusion model." Magnetic Resonance in Medicine, 2021; 85(3):1681-1696.
  


• Ajin Joy, Mathews Jacob and Joseph Suresh Paul. "Directionality Guided Non-Linear Diffusion Compressed Sensing MR Image Reconstruction." Magnetic Resonance in Medicine, 2019; 82(6):2326-2342.
  [ view document ]  "Download MATLAB codes"


• Ajin Joy and Joseph Suresh Paul. "A Mixed-order Non-Linear Diffusion Compressed Sensing MR Image Reconstruction." Magnetic Resonance in Medicine, 2018; 80(5):2215–2222.
  [ view document ]  "Download MATLAB codes"


• Ajin Joy and Joseph Suresh Paul. "Multichannel compressed sensing MR image reconstruction using statistically optimized nonlinear diffusion." Magnetic Resonance in Medicine, 2017; 78(2):754-62.
  [ view document ]  "Download MATLAB codes"


• Akshara P. Krishnan, Ajin Joy, and Joseph Suresh Paul. "Improved image reconstruction of low-resolution multichannel phase contrast angiography." Journal of Medical Imaging. 2016 Jan;3(1):014001.; doi: 10.1117/1.JMI.3.1.014001

• Andres Saucedo, Ajin Joy, Eric S. Daar, Mario Guerrero, Joseph Suresh Paul, Manoj K. Sarma and M. Albert Thomas. "Comparison of Compressed Sensing Reconstruction for 3D Echo Planar Spectroscopic Imaging data using Total Variation and Statistically Optimized Perona-Malik Non-linear Diffusion." In Proceedings of the Joint Annual Meeting of ISMRM-ESMRMB, Paris, France, 2018 June. http://archive.ismrm.org/2018/3843.html


• Ajin Joy and Joseph Suresh Paul. "A Rapid Non-Linear Diffusion Compressed Sensing MR Image Reconstruction for Optimization of Speed-Quality Tradeoff." In Proceedings of 11th Indian Conference on Computer Vision, Graphics and Image Processing (ICVGIP), Hyderabad, India, 2018.


• Ajin Joy and Joseph Suresh Paul. "Improving Image Quality and Convergence Rate of Perona-Malik Diffusion based Compressed Sensing MR Image Reconstruction by Gradient Correction." In Proceedings of 3rd International Conference on Computer Vision & Image Processing (CVIP), Jabalpur, India, 2018.