naa a22 4500 510806961 CHVBK 20180411083423.0 cr unu---uuuuu 180411e20130101xx s 000 0 eng 10.1007/s11548-012-0746-x doi (NATIONALLICENCE)springer-10.1007/s11548-012-0746-x Precise X-ray and video overlay for augmented reality fluoroscopy [Elektronische Daten] [Xin Chen, Lejing Wang, Pascal Fallavollita, Nassir Navab] Purpose: The camera-augmented mobile C-arm (CamC) augments any mobile C-arm by a video camera and mirror construction and provides a co-registration of X-ray with video images. The accurate overlay between these images is crucial to high-quality surgical outcomes. In this work, we propose a practical solution that improves the overlay accuracy for any C-arm orientation by: (i) improving the existing CamC calibration, (ii) removing distortion effects, and (iii) accounting for the mechanical sagging of the C-arm gantry due to gravity. Methods: A planar phantom is constructed and placed at different distances to the image intensifier in order to obtain the optimal homography that co-registers X-ray and video with a minimum error. To alleviate distortion, both X-ray calibration based on equidistant grid model and Zhang's camera calibration method are implemented for distortion correction. Lastly, the virtual detector plane (VDP) method is adapted and integrated to reduce errors due to the mechanical sagging of the C-arm gantry. Results: The overlay errors are 0.38±0.06mm when not correcting for distortion, 0.27±0.06mm when applying Zhang's camera calibration, and 0.27±0.05mm when applying X-ray calibration. Lastly, when taking into account all angular and orbital rotations of the C-arm, as well as correcting for distortion, the overlay errors are 0.53±0.24mm using VDP and 1.67±1.25mm excluding VDP. Conclusion: The augmented reality fluoroscope achieves an accurate video and X-ray overlay when applying the optimal homography calculated from distortion correction using X-ray calibration together with the VDP. CARS, 2012 X-ray nationallicence Calibration nationallicence Homography nationallicence Camera-augmented mobile C-arm nationallicence Augmented reality nationallicence Chen Xin Fakultät für Informatik, Technische Universität München, Munich, Germany aut Wang Lejing Fakultät für Informatik, Technische Universität München, Munich, Germany aut Fallavollita Pascal Fakultät für Informatik, Technische Universität München, Munich, Germany aut Navab Nassir Fakultät für Informatik, Technische Universität München, Munich, Germany aut International Journal of Computer Assisted Radiology and Surgery Springer-Verlag 8/1(2013-01-01), 29-38 1861-6410 8:1<29 2013 8 11548 https://doi.org/10.1007/s11548-012-0746-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11548-012-0746-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Chen Xin Fakultät für Informatik, Technische Universität München, Munich, Germany aut NATIONALLICENCE 700 1- Wang Lejing Fakultät für Informatik, Technische Universität München, Munich, Germany aut NATIONALLICENCE 700 1- Fallavollita Pascal Fakultät für Informatik, Technische Universität München, Munich, Germany aut NATIONALLICENCE 700 1- Navab Nassir Fakultät für Informatik, Technische Universität München, Munich, Germany aut NATIONALLICENCE 773 0- International Journal of Computer Assisted Radiology and Surgery Springer-Verlag 8/1(2013-01-01), 29-38 1861-6410 8:1<29 2013 8 11548 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer