EGi Geoscan, Руководство пользователя, Страница: 75 / 115

GeoScan User Manual | 8100550-03
•
2018-10-26 |
FOR SCIENTIFIC RESEARCH PURPOSES
75
Scanner LED Stripe and Software Marker Feedback
Remember that the 3D sensor cloud should contain two blank spaces .
The COM and S/N (serial number) pedestals should not register in the
3D sensor cloud but, instead, should appear as blank spaces. If they do
appear, they will need to be deleted. See section 5.3.3.
Other blank spaces in the 3D sensor cloud indicate areas where one or
more sensors still need to be scanned.
7
When the GSN is mostly scanned and the marking of sensors has
slowed (few, infrequent bloops), pause scanning.
Depending upon how you initiated scanning, double-press the
scan trigger
,
click the onscreen
Pause
button, or release the
scan trigger
.
8
Review the 3D sensor cloud by using your mouse to rotate it (see
section 2.4.4.1).
There should be:
•
no blank areas where there should be markers
•
no stray markers
•
no makers for the COM or S/N pedestals
•
nasion sensor between the eyebrows
•
vertex sensor (REF/Cz) at the top, center of the head
•
blank areas for the ear holes
•
sensors above the ears
•
alignment between the GSN on the subject’s head and
the markers of the 3D sensor cloud (see section 5.1)
•
most sensors present
For a 256-channel GSN, 253 out of 257 markers are sufficient for processing
sensor locations. That’s about 95% of the sensors. Be aware that alignment
sensors will be numbered differently, depending upon a GSN’s channel count.
9
If markers are missing or questionable, fix them as follows.
Otherwise, continue with probing. See section 6.7.