Fig 1.
Diagrams of connections between hardware and software components of the VR digitizer system.
(A) Complete Vive hardware setup, with two controllers each communicating with the computer through the HMD, two trackers connected via independent wireless adapters, and all tracked devices receiving signals from two Lighthouses. (B) Reduced Vive hardware setup, with a single tracker and controller communicating through wireless adapters without an HMD. (C) Connections between software components.
Fig 2.
Example of endpoint calibration.
(A) Visualization of calibration process, showing five samples measured with varied rotations about the selected endpoint. Black spheres indicate the estimated endpoint location for each sample, and blue lines connect the estimated endpoint to the controller origin. (B) Final endpoint location relative to controller. The endpoint (red sphere) is offset from controller since it was defined as a point at the end of a micro USB cable stub not included in the controller 3D model.
Fig 3.
Screenshot of main VRDigitizer GUI window.
Fig 4.
VRDigitizer localization results for a single subject (S06).
In (A) and (B), the green and gray circles indicate fiducials and electrodes measured for the VRDigitizer TwoTrackers condition, while the blue and black circles indicate fiducials and electrodes measured for the Brainsight reference condition; the colors of the lines connecting corresponding electrodes across the two datasets are indicative of the magnitude of localization error. Interpolated localization error is plotted with the same color scale on a projected 2D scalp topography in (C). Here, the two datasets were aligned by electrodes, and the subject’s scalp surface was aligned by the reference dataset anatomical fiducials. Electrodes appear offset from the scalp surface due to the selected digitization point for each electrode being on the top surface of the 3-mm thick electrode mount.
Fig 5.
Localization errors for phantom measurements.
Aligned by electrodes (A,B) or by fiducials (C,D). Individual results are shown in (A) and (C), with each box-and-whisker corresponding to a single dataset and each point corresponding to localization error for a single electrode. Grouped results are shown in (B) and (D), with each point corresponding to a scalar RMSE error aggregated from a single dataset. Labeled values in (B) and (D) indicate p values from uncorrected two-tailed Welch’s t-tests.
Fig 6.
Localization errors for subject measurements.
Aligned by electrodes (A,B) or by fiducials (C,D). Individual results are shown in (A) and (C), with each box-and-whisker corresponding to a single dataset and each point corresponding to localization error for a single electrode. Grouped results are shown in (B) and (D), with each point corresponding to a scalar RMSE error aggregated from a single dataset. Labeled values in (B) and (D) indicate p values from uncorrected two-tailed Welch’s t-tests.