Computer-Assisted System for Endoscopic Surgery with On-Line 3D Reconstruction and Visualization
| Autor: | Yi-Chiao Chen, 陳亦喬 |
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| Rok vydání: | 2004 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 92 Recently, the endoscopic minimally invasive surgery becomes popular than ever before because of its advantages in small incisions, faster recovery of the patients, and reduction of medical costs. However, seeing the images from endoscopes is similar to see scenes with only one naked eye. The surgeon usually cannot determine the size of organs or the distance between them exactly due to the lack of stereo visual perception. In order to resolve this problem, we propose a computer-assisted system for endoscopic surgery in this thesis. This system reconstructs a 3-D model of human organs or tissues from an endoscopic images sequence. And a 3-D tracker called miniBIRD is attached to the surgical instrument to obtain the 3-D position of instrument and to update the reconstructed structure of human organs or tissues. This system is composed of four procedures: feature extraction and tracking, 3-D model reconstruction, 3-D model updating, and instrument model visualization. According to the shape and texture of organs, we enhance all images by histogram equalization and intensity normalization. Moreover, the Kanade-Lucas-Tomasi (KLT) tracker is improved by extracting edge features and using the motion restriction mechanism. The tracked 2-D feature points by KLT tracker are then used to reconstruct the 3-D model by using the factorization algorithm based on the paraperspective projection. The factorization algorithm is modified by adopting 3-D points with known coordinates to build a 3-D model with real size. For refining the reconstructed 3-D structure, the surgeon can acquire additional 3-D positions from some characteristic feature points by miniBIRD and perform the improved factorization method again to generate a more accurate model. In addition, the miniBIRD is attached to the surgical instrument whose position is consequently tracked in real-time. Since the organ structure and surgical instrument are both in the same coordinate system, the distance between organs and instrument, the velocity of instrument, and the inserting angle of instrument can all be estimated to give surgeons a proper warning during the operation. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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