

Scientific Publications
News and Events
Conferences
Workshops
Request Info
Newsletter
Corporate
Contact


Research Products
Clinical Products
Research
BEL


Clinical EEG Overview


Support


Home

Geodesic Photogrammetry System

	The Geodesic Photogrammetry System (GPS) enables you to reconstruct 3D sensor positions, which you can then register with MR images. GPS is fast—center the patient in the multicamera-equipped GPS dome, take the pictures, and the patient is free to go. Mark the sensor positions on the images later, when it's convenient for you.	Working Principle Acquisition Features Sensor Reconstruction Features Back to Products page

Working Principle Sensor registration in four steps: 1. Position a patient wearing a GSN in the center of the camera-equipped GPS dome. 2. Use the streaming video feed in Net Station to ensure good patient position and sensor visibility. Take the pictures, and the patient is free to go. 3. View the photos in Net Station, mark the sensors with the mouse, generate 3D head-centered coordinates, review the results, and edit your work—all at your leisure. 4. Mark the fiducial points and export the sensor positions for precise sensor localization and coregistration of EEG and MRI data. top		Working Principle Images
Acquisition Features • Use GPS only with the Geodesic Sensor Nets. • Select GSN type from a list of standard models. • Use motorized lift to adjust cameras to patients of various heights. • Control cameras from within the Net Station software. • Stream 1, 3, or all 11 camera images for easy patient placement. • Acquire images in less than one-tenth of a second. • Check for good sensor visibility before saving images to disk. • Retake images, if needed—it's that easy. top		Acquisition Images
Sensor Reconstruction Features • Mark GSN cardinal points in the images and triangulate positions with Net Station software to create an initial sensor set; fine-tune that set by marking and triangulating the remaining sensors. • Edit marks, or even redo the sensor-marking process, if needed. • Use the many position-solving tools, including the 3D point-sensor cloud, camera filters, camera overlays, and Observations and Sensor Locations windows. • Acquire 1-mm-accurate positions. (See Russell, G. S., Eriksen, K. J., Poolman, P., Luu, P., & Tucker, D. M. [2005]. Geodesic photogrammetry for localizing sensor positions in dense-array EEG. Clinical Neurophysiology, 116, 1130-1140.) top		Sensor Reconstruction Images

©2008 Electrical Geodesics, Inc.