Fully Automatic Registration Methods for Chest X-Ray Images

Yu Ching Lee, Muhammad Adil Khalil, Jui Huan Lee, Abdan Syakura, Yi Fang Ding, Ching Wei Wang

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Purpose: Image registration is important in medical applications accomplished by improving healthcare technology in recent years. Various studies have been proposed in medical applications, including clinical track of events and updating the treatment plan for radiotherapy and surgery. This study presents a fully automatic registration system for chest X-ray images to generate fusion results for difference analysis. Using the accurate alignment of the proposed system, the fusion result indicates the differences in the thoracic area during the treatment process. Methods: The proposed method consists of a data normalization method, a hybrid L-SVM model to detect lungs, ribs and clavicles for object recognition, a landmark matching algorithm, two-stage transformation approaches and a fusion method for difference analysis to highlight the differences in the thoracic area. In evaluation, a preliminary test was performed to compare three transformation models, with a full evaluation process to compare the proposed method with two existing elastic registration methods. Results: The results show that the proposed method produces significantly better results than two benchmark methods (P-value ≤ 0.001). The proposed system achieves the lowest mean registration error distance (MRED) (8.99 mm, 23.55 pixel) and the lowest mean registration error ratio (MRER) w.r.t. the length of image diagonal (1.61%) compared to the two benchmark approaches with MRED (15.64 mm, 40.97 pixel) and (180.5 mm, 472.69 pixel) and MRER (2.81%) and (32.51%), respectively. Conclusions: The experimental results show that the proposed method is capable of accurately aligning the chest X-ray images acquired at different times, assisting doctors to trace individual health status, evaluate treatment effectiveness and monitor patient recovery progress for thoracic diseases.

Original languageEnglish
JournalJournal of Medical and Biological Engineering
Publication statusPublished - Dec 2021


  • Chest X-ray image comparison
  • Difference analysis
  • Fully automatic image registration

ASJC Scopus subject areas

  • Biomedical Engineering


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