Intraoperative camera calibration for endoscopic surgery

Abstract

A surgical navigation system employs an endoscope (30) and an imaging unit (80). The endoscope (30) include an electromagnetic tracker (40) within a working channel of endoscope (30) for generating electromagnetic sensing signals indicative of one or more poses of the endoscope (30) within an anatomical region, and an endoscopic camera (50) within an imaging channel of the endoscope (30) for generating endoscopic images of the anatomical region. The imaging unit (80) executes an intraoperative calibration of the electromagnetic tracker (40) and the endoscopic camera (50) as a function of an image registration between the preoperative scan image of a calibration site within the anatomical region and one or more endoscopic images of the calibration site within the anatomical region.

Description

technical field

[0001] The present invention generally relates to real-time tracking of surgical tools within an anatomical region of the body based on pre-operative scan images and endoscopic images of the anatomical region. The present invention specifically relates to calculating an offset transformation matrix between an endoscopic camera and an electromagnetic ("EM") tracker using a pre-operative scan image of an anatomical region and one or more endoscopic images. Background technique

[0002] EM-guided endoscopy has been recognized as a valuable tool for many pulmonary applications. The advantage of this technique over traditional endoscopy is based on the real-time link to a three-dimensional ("3D") roadmap of the lung while performing an interventional procedure. This linking requires tracking of the endoscope tip in a global coordinate system to thus integrate endoscopic images of the lungs with preoperative scan images of the lungs (e.g. computed tomography image...

Examples

Embodiment Construction

[0021] refer to figure 1 , the present invention is premised on a technique 60 for performing both image registration and tracker / camera calibration during an intervention involving an endoscope 30 . This registration / calibration technique 60 is based on the idea that the offset distance between the video frame from the endoscopic camera 50 and the tracked frame from the EM tracker 40 is determined by the anatomical region acquired from the endoscopic camera 50 ( For example, inconsistencies in two-dimensional ("2D") projection images between an endoscopic image of the lungs) and a virtual flythrough of image frames of the pre-operative scan image 10 of the anatomical region are reflected. Thus, the registration / calibration technique 60 has the ability to distinguish such spatial differences, and the reconstructed spatial correspondence is used to estimate a calibration matrix between the EM tracking coordinate system 41 and the endoscopic camera coordinate system 51 .

[002...

technical field

[0001] The present invention generally relates to real-time tracking of surgical tools within an anatomical region of the body based on pre-operative scan images and endoscopic images of the anatomical region. The present invention specifically relates to calculating an offset transformation matrix between an endoscopic camera and an electromagnetic ("EM") tracker using a pre-operative scan image of an anatomical region and one or more endoscopic images. Background technique

[0002] EM-guided endoscopy has been recognized as a valuable tool for many pulmonary applications. The advantage of this technique over traditional endoscopy is based on the real-time link to a three-dimensional ("3D") roadmap of the lung while performing an interventional procedure. This linking requires tracking of the endoscope tip in a global coordinate system to thus integrate endoscopic images of the lungs with preoperative scan images of the lungs (e.g. computed tomography image...

Examples

Embodiment Construction

[0021] refer to figure 1 , the present invention is premised on a technique 60 for performing both image registration and tracker / camera calibration during an intervention involving an endoscope 30 . This registration / calibration technique 60 is based on the idea that the offset distance between the video frame from the endoscopic camera 50 and the tracked frame from the EM tracker 40 is determined by the anatomical region acquired from the endoscopic camera 50 ( For example, inconsistencies in two-dimensional ("2D") projection images between an endoscopic image of the lungs) and a virtual flythrough of image frames of the pre-operative scan image 10 of the anatomical region are reflected. Thus, the registration / calibration technique 60 has the ability to distinguish such spatial differences, and the reconstructed spatial correspondence is used to estimate a calibration matrix between the EM tracking coordinate system 41 and the endoscopic camera coordinate system 51 .

[002...

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