Mr. Özgür Güler Profile

Özgür Güler

at Medizinische Univ Innsbruck

SPIE Involvement:

Author

Publications (2)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 2 March 2011 Paper

Online temporal synchronization of pose and endoscopic video streams

Özgür Güler, Ziv Yaniv, Wolfgang Freysinger

Proceedings Volume 7964, 79641M (2011) https://doi.org/10.1117/12.877720

KEYWORDS: Video, Endoscopes, Endoscopy, Calibration, Navigation systems, Image registration, Cameras, Data acquisition, Operating systems, Optical spheres

Read Abstract +

Computer assisted navigation systems that combine real-time endoscopy images with pre-operative volumetric data sets aim at improving the physician's understanding of the underlying anatomical structures. To achieve accurate and safe guidance these systems are required to provide a consistent representation of the physical world. This implies that all data streams are synchronized. In our case, we are dealing with synchronization of tracking data and a video stream obtained by a tracked endoscope. Previously, such synchronization was obtained pre-operatively using phantoms. This type of approach assumes a constant latency between the data streams and is less desirable for clinical use due to the required additional hardware. In this work we describe an online temporal synchronization method. The method is based on the observation that in clinical practice the endoscope is not in constant motion. By identifying corresponding stationary points in the video and tracking streams temporal synchronization can be performed online in a manner that is transparent to the user. Initial evaluation of our approach in a laboratory study has shown that it provides comparable estimates to a phantom based approach we had previously proposed.

Proceedings Article | 24 February 2010 Paper

Exploring the clinical validity of predicted TRE in navigation

M. Bickel, Ö. Güler, F. Kral, F. Schwarm, W. Freysinger

Proceedings Volume 7625, 762526 (2010) https://doi.org/10.1117/12.843656

KEYWORDS: Image registration, Skull, Navigation systems, Head, Statistical analysis, Visualization, Data modeling, Error analysis, Surgery, MATLAB

Read Abstract +

In a detailed laboratory investigation we performed a series of experiments in order to assess the validity of the widely used TRE concept to predict the application accuracy. On base of 1mm CT scan a plastic skull, a cadaver head and a volunteer were registered to an in house navigation system. We stored the position data of an optical camera (NDI Polaris) for registration with pre-defined CT coordinates. For every specimen we choose 3, 5, 7 and 9 registration and 10 evaluation points, respectively, performing 10 registrations. The data were evaluated both with the Arun and the Horn approaches. The vectorial difference between actual and predefined position in the CT data set was stored and evaluated for FRE and TRE. Evaluation and visualization was implemented in Matlab. The data were analyzed, specifically for normal distribution, with MS Excel and SPSS Version 15.0. For the plastic skull and the anatomic specimen submillimetric application accuracy was found experimentally and confirmed by the calculated TRE. Since for the volunteer no Titanium screws were implanted anatomic landmarks had to be used for registration and evaluation; an application accuracy in the low millimeter regime was found in all approaches. However, the detailed statistical analysis of the data revealed that the model predictions and the actual measurements do not exhibit a strong statistical correlation (p < 0.05). These data suggest that the TRE predictions are too optimistic and should be used with caution intraoperatively.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years