Tracing Rib Contour Lines by Respiratory Motion Compensation from an X-ray Image Sequence

The ordinary respiration rib motion research is usually based on the rib contour line extraction. Thus, the motion estimation is extremely effected by the extraction result. However, the research of the rib contour line extraction is not well articulated in the knotty topic, especially for the single xray image. In this paper, we explore a new method, which can solve the problem robustly through the respiratory motion information from an x-ray image sequence. We estimate the motion along with the extraction and compare with the traditional method where the rib contour lines are necessarily extracted before the respiratory motion. We found that the detected motion results even more promising to the contour line extraction. To analyze the rib motion pattern during respiration, a cross-correlation coefficient method is proposed to estimate the thoracic 2D motion, based on a bucket handle motion model. As a result, various parts of the rib structure are accentuated from the other tissues compensating by the obtained motion vector. The compensation is also applied to reconstruct rib shapes and positions for the fast and robust tracing. Experimental results show the effectiveness and usefulness of the proposed method.