Intelligent Parameter Tuning in Optimization-based Iterative CT Reconstruction via Deep Reinforcement Learning

Chenyang Shen, Yesenia Gonzalez, Liyuan Chen, Steve B. Jiang, Xun Jia

Research output: Contribution to journalArticle

19 Scopus citations


A number of image-processing problems can be formulated as optimization problems. The objective function typically contains several terms specifically designed for different purposes. Parameters in front of these terms are used to control the relative importance among them. It is of critical importance to adjust these parameters, as quality of the solution depends on their values. Tuning parameters is a relatively straightforward task for a human, as one can intuitively determine the direction of parameter adjustment based on the solution quality. Yet manual parameter tuning is not only tedious in many cases, but becomes impractical when a number of parameters exist in a problem. Aiming at solving this problem, this paper proposes an approach that employs deep reinforcement learning to train a system that can automatically adjust parameters in a humanlike manner. We demonstrate our idea in an example problem of optimization-based iterative CT reconstruction with a pixelwise total-variation regularization term. We set up a Parameter- Tuning Policy Network (PTPN), which maps a CT image patch to an output that specifies the direction and amplitude by which the parameter at the patch center is adjusted. We train the PTPN via an end-to-end reinforcement learning procedure.We demonstrate that under the guidance of the trained PTPN, reconstructed CT images attain quality similar or better than those reconstructed with manually tuned parameters.

Original languageEnglish (US)
JournalIEEE Transactions on Medical Imaging
StateAccepted/In press - Apr 4 2018


  • Computed tomography
  • Image quality
  • Image reconstruction
  • Image reconstruction -iterative methods
  • Inverse methods
  • Machine learning
  • Machine learning
  • Optimization
  • Radio frequency
  • Tuning
  • x-ray imaging and computed tomography

ASJC Scopus subject areas

  • Software
  • Radiological and Ultrasound Technology
  • Computer Science Applications
  • Electrical and Electronic Engineering

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