Optical-Tracker-Based 3D Reconstruction for Endoscopic Environment

2012 ◽  
Vol 249-250 ◽  
pp. 1277-1282
Author(s):  
Bo Yang ◽  
Ya Zhou ◽  
Xiao Ming Hu ◽  
Jun Qin Lin ◽  
Qiao Na Xing
Keyword(s):  
Minimally Invasive ◽  
Tracking System ◽  
3D Structure ◽  
Three Dimensional ◽  
Optical Tracking ◽  
Two Dimensional ◽  
Invasive Treatment ◽  
Optical Tracking System ◽  
Structure Information ◽  
3D Information

Endoscopic surgery is increasing for minimally invasive treatment in recent years.But the conventional two-dimensional endoscope technique cannot provide three-dimensional information for surgeon. Lacking depth and other 3D information often made doctorshave to carry out the surgery depending heavily clinical experience.In response to the above described issues,this paper proposed a method based on improved SIFT algorithmto recover 3D structure information of the endoscopic environment, with the help of an optical tracking system which can provide the orientation of the camera in real time. The proposed approach is evaluated on sequence digital images gotten from an 1394 camera and the experimental results show that the proposed approach iseffective.

Accurate Infrared Tracking System for Immersive Virtual Environments

2011 ◽  
Vol 2 (2) ◽  
pp. 49-73 ◽  
Author(s):  
Filipe Gaspar ◽  
Rafael Bastos ◽  
Miguel Sales
Keyword(s):  
Virtual Environments ◽  
Large Scale ◽  
Tracking System ◽  
3D Structure ◽  
Optical Tracking ◽  
Frame Rate ◽  
Input Device ◽  
Optical Tracking System ◽  
Immersive Virtual Environments ◽  
Hardware Configuration

In large-scale immersive virtual reality (VR) environments, such as a CAVE, one of the most common problems is tracking the position of the user’s head while he or she is immersed in this environment to reflect perspective changes in the synthetic stereoscopic images. In this paper, the authors describe the theoretical foundations and engineering approach adopted in the development of an infrared-optical tracking system designed for large scale immersive Virtual Environments (VE) or Augmented Reality (AR) settings. The system is capable of tracking independent retro-reflective markers arranged in a 3D structure in real time, recovering all possible 6DOF. These artefacts can be adjusted to the user’s stereo glasses to track his or her head while immersed or used as a 3D input device for rich human-computer interaction (HCI). The hardware configuration consists of 4 shutter-synchronized cameras attached with band-pass infrared filters and illuminated by infrared array-emitters. Pilot lab results have shown a latency of 40 ms when simultaneously tracking the pose of two artefacts with 4 infrared markers, achieving a frame-rate of 24.80 fps and showing a mean accuracy of 0.93mm/0.51º and a mean precision of 0.19mm/0.04º, respectively, in overall translation/rotation, fulfilling the requirements initially defined.

INTRA- AND INTER-EXAMINER RELIABILITY OFIN VIVOTHREE-DIMENSIONAL MEASUREMENT OF THE SCAPULAR POSES USING A MARKER-BASED LOCATOR

2018 ◽  
Vol 30 (01) ◽  
pp. 1850001
Author(s):  
Mei-Ying Kuo ◽  
Shih-Wun Hong ◽  
Jia-Da Li ◽  
Tung-Wu Lu ◽  
Horng-Chaung Hsu
Keyword(s):  
Tracking System ◽  
Three Dimensional ◽  
Optical Tracking ◽  
Optical Tracking System ◽  
Rater Reliability ◽  
Reliability Models ◽  
Scapular Kinematics ◽  
Dimensional Measurement ◽  
Shoulder Flexion ◽  
Shoulder Complex

Accurate measurement of the three-dimensional scapular kinematics is essential for a better understanding of the mechanical interactions between the scapula and the other segments of the shoulder complex. The purposes of the study were: (i) to development a marker-based scapular locator for measuring scapular poses, and (ii) to determine the intra- and inter-rater reliability of the locator in terms of intra-class correlations (ICC). Twenty-two healthy volunteers without shoulder pathologies participated in the current study. Each subject was tested separately by two raters using the marker-based scapular locator while performing static shoulder flexion at 20, 40, 60, 80, 100 and 120 degrees in the scapular plane. Two reliability models, ICC[Formula: see text] and ICC[Formula: see text], were used to analyze the intra- and inter-rater reliability for scapular rotations and translations. Good to excellent intra-user reliability for both examiners was found for the scapular rotations (range: 0.82–0.99) and displacements (range: 0.72–0.99) for different shoulder flexion conditions. Good to excellent inter-rater reliability was found for scapular rotations (range: 0.63–0.95) and translations (range: 0.70–0.95) for all conditions. The results showed that high intra- and inter-examiner reliability could be achieved for scapular rotations and translation using the marker-based scapular locator. The proposed new scapular locator with an optical tracking system will be helpful for future applications in basic and clinical studies of the shoulder complex during arm movements.

scholarly journals Three-Dimensional Registration of Freehand-Tracked Ultrasound to CT Images of the Talocrural Joint

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2375 ◽  
Author(s):  
Nazlı Tümer ◽  
Aimee Kok ◽  
Frans Vos ◽  
Geert Streekstra ◽  
Christian Askeland ◽  
...  
Keyword(s):  
Tracking System ◽  
Three Dimensional ◽  
Optical Tracking ◽  
Monogenic Signal ◽  
Optical Tracking System ◽  
Talocrural Joint ◽  
Chondral Defects ◽  
Tracked Ultrasound ◽  
Signal Features ◽  
Operative Planning

A rigid surface–volume registration scheme is presented in this study to register computed tomography (CT) and free-hand tracked ultrasound (US) images of the talocrural joint. Prior to registration, bone surfaces expected to be visible in US are extracted from the CT volume and bone contours in 2D US data are enhanced based on monogenic signal representation of 2D US images. A 3D monogenic signal data is reconstructed from the 2D data using the position of the US probe recorded with an optical tracking system. When registering the surface extracted from the CT scan to the monogenic signal feature volume, six transformation parameters are estimated so as to optimize the sum of monogenic signal features over the transformed surface. The robustness of the registration algorithm was tested on a dataset collected from 12 cadaveric ankles. The proposed method was used in a clinical case study to investigate the potential of US imaging for pre-operative planning of arthroscopic access to talar (osteo)chondral defects (OCDs). The results suggest that registrations with a registration error of 2 mm and less is achievable, and US has the potential to be used in assessment of an OCD’ arthroscopic accessibility, given the fact that 51% of the talar surface could be visualized.

Accurate Infrared Tracking System for Immersive Virtual Environments

2012 ◽  
pp. 318-343
Author(s):  
Filipe Gaspar ◽  
Rafael Bastos ◽  
Miguel Sales
Keyword(s):  
Virtual Environments ◽  
Large Scale ◽  
Tracking System ◽  
3D Structure ◽  
Optical Tracking ◽  
Frame Rate ◽  
Input Device ◽  
Optical Tracking System ◽  
Immersive Virtual Environments ◽  
Hardware Configuration

In large-scale immersive virtual reality (VR) environments, such as a CAVE, one of the most common problems is tracking the position of the user’s head while he or she is immersed in this environment to reflect perspective changes in the synthetic stereoscopic images. In this paper, the authors describe the theoretical foundations and engineering approach adopted in the development of an infrared-optical tracking system designed for large scale immersive Virtual Environments (VE) or Augmented Reality (AR) settings. The system is capable of tracking independent retro-reflective markers arranged in a 3D structure in real time, recovering all possible 6DOF. These artefacts can be adjusted to the user’s stereo glasses to track his or her head while immersed or used as a 3D input device for rich human-computer interaction (HCI). The hardware configuration consists of 4 shutter-synchronized cameras attached with band-pass infrared filters and illuminated by infrared array-emitters. Pilot lab results have shown a latency of 40 ms when simultaneously tracking the pose of two artefacts with 4 infrared markers, achieving a frame-rate of 24.80 fps and showing a mean accuracy of 0.93mm/0.51º and a mean precision of 0.19mm/0.04º, respectively, in overall translation/rotation, fulfilling the requirements initially defined.

Endoscopic Augmented Reality Navigation System for Endonasal Transsphenoidal Surgery to Treat Pituitary Tumors: Technical Note

Neurosurgery ◽  
2002 ◽  
Vol 50 (6) ◽  
pp. 1393-1397 ◽  
Author(s):  
Takakazu Kawamata ◽  
Hiroshi Iseki ◽  
Takao Shibasaki ◽  
Tomokatsu Hori
Keyword(s):  
Augmented Reality ◽  
Navigation System ◽  
Transsphenoidal Surgery ◽  
Tracking System ◽  
Three Dimensional ◽  
Pituitary Tumors ◽  
Optical Tracking ◽  
Navigation Systems ◽  
Optical Tracking System ◽  
Light Emitting

Abstract OBJECTIVE Endoscopes have been commonly used in transsphenoidal surgery to treat pituitary tumors, to compensate for the narrow surgical field. Although many navigation systems have been introduced for neurosurgical procedures, there have been few reports of navigation systems for endoscopic operations. This report presents our recently developed, endoscopic, augmented reality (AR) navigation system. METHODS The technology is based on the principles of AR environment technology. The system consisted of a rigid endoscope with light-emitting diodes, an optical tracking system, and a controller. The operation of the optical tracking system was based on two sets of infrared light-emitting diodes, which measured the position and orientation of the endoscope relative to the patient's head. We used the system during endonasal transsphenoidal operations to treat pituitary tumors in 12 recent cases. RESULTS Anatomic, “real,” three-dimensional, virtual images of the tumor and nearby anatomic structures (including the internal carotid arteries, sphenoid sinuses, and optic nerves) were superimposed on real- time endoscopic live images. The system also indicated the positions and directions of the endoscope and the endoscopic beam in three-dimensional magnetic resonance imaging or computed tomographic planes. Furthermore, the colors of the wire-frame images of the tumor changed according to the distance between the tip of the endoscope and the tumor. These features were superior to those of conventional navigation systems, which are available only for operating microscopes. CONCLUSION The endoscopic AR navigation system allows surgeons to perform accurate, safe, endoscope-assisted operations to treat pituitary tumors; it is particularly useful for reoperations, in which midline landmarks may be absent. We consider the AR navigation system to be a promising tool for safe, minimally invasive, endonasal, transsphenoidal surgery to treat pituitary tumors.

Seismic Response of Rocking Blocks

2018 ◽  
Vol 34 (3) ◽  
pp. 1051-1063 ◽  
Author(s):  
Kari Klaboe ◽  
Santiago Pujol ◽  
Lucas Laughery
Keyword(s):  
Tracking System ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Economic Loss ◽  
Optical Tracking ◽  
Optical Tracking System ◽  
Earthquake Simulator ◽  
Highly Sensitive ◽  
Concrete Blocks ◽  
Rocking Response

Monuments, equipment, chimneys, and older intake structures for dams all may rock during strong ground motions. These and other rocking objects are vulnerable to overturning, leading to potential economic loss and disruption to affected communities. The need for methods to estimate rocking response is supported by the breadth of structures susceptible to overturning and their prevalence in the built environment. Previous research on the development of numerical tools for the simulation of rocking behavior in response to earthquake motions has shown that simulation results are highly sensitive to input parameters, and that data from experimental tests are needed to calibrate these tools. To provide such test data, 312 experiments were conducted on unanchored concrete blocks on an earthquake simulator. The tests were instrumented using accelerometers and a three-dimensional (3-D), noncontact optical tracking system. All data are available online and can be accessed via DOI: 10.4231/R7FB513S and in interactive form at datacenterhub.org/resources/14255 . Two simple examples are provided to show how the data may be used. Readers are encouraged to use the data as a means for evaluating more detailed methods to evaluate rocking response.

scholarly journals In Vitro and In Vivo Assessment of a New Workflow for the Acquisition of Mandibular Kinematics Based on Portable Tracking System with Passive Optical Reflective Markers

2021 ◽  
Vol 11 (9) ◽  
pp. 3947
Author(s):  
Marco Farronato ◽  
Gianluca M. Tartaglia ◽  
Cinzia Maspero ◽  
Luigi M. Gallo ◽  
Vera Colombo
Keyword(s):  
Measurement Error ◽  
Tracking System ◽  
Intraclass Correlation ◽  
Optical Tracking ◽  
Optical Tracking System ◽  
Rater Reliability ◽  
Tracking Device ◽  
Mandibular Kinematics

Clinical use of portable optical tracking system in dentistry could improve the analysis of mandibular movements for diagnostic and therapeutic purposes. A new workflow for the acquisition of mandibular kinematics was developed. Reproducibility of measurements was tested in vitro and intra- and inter-rater repeatability were assessed in vivo in healthy volunteers. Prescribed repeated movements (n = 10) in three perpendicular directions of the tracking-device coordinate system were performed. Measurement error and coefficient of variation (CV) among repetitions were determined. Mandibular kinematics of maximum opening, left and right laterality, protrusion and retrusion of five healthy subjects were recorded in separate sessions by three different operators. Obtained records were blindly examined by three observers. Intraclass correlation coefficient (ICC) was calculated to estimate inter-rater and intra-rater reliability. Maximum in vitro measurement error was 0.54 mm and CV = 0.02. Overall, excellent intra-rater reliability (ICC > 0.90) for each variable, general excellent intra-rater reliability (ICC = 1.00) for all variables, and good reliability (ICC > 0.75) for inter-rater tests were obtained. A lower score was obtained for retrusion with “moderate reliability” (ICC = 0.557) in the inter-rater tests. Excellent repeatability and reliability in optical tracking of primary movements were observed using the tested portable tracking device and the developed workflow.

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