GE Everest XLG3 VideoProbe Operating Manual page 110

102 Chapter 7 Measuring Features and Defects
Types of Stereo Measurement
This table specifically addresses cursor placement for each type of stereo measurement.
For the complete procedure, see
Example —
Type "Matching Cursors" on Right Image
Length
Point to Line
Depth
"To Take a Stereo Measurement"
GE Inspection Technologies XLG3 VideoProbe System
on page 100.
Description
A linear (point-to-point)
measurement.
The perpendicular distance
from a point to a line.
The perpendicular distance
between a surface and a point
above or below it. Used to
evaluate changes due to wear,
misalignment, and other
causes.
Negative measurements
indicate that the point lies
below the plane. Positive
measurements indicate that it
lies above.
Cursor Placement
On Left Image
Place both cursors.
Place the first two cursors to
define a reference line. Place
the third cursor at the
perpendicular distance you
want to measure.
Place the first three cursors to
define a reference plane. Place
the fourth cursor at the
perpendicular distance you
want to measure.
Note: Depth measurements
taken at a low accuracy index
are particularly sensitive to the
matching cursor's position.
If the accuracy index is low,
increase it by bringing the
probe tip closer. If you cannot
increase the accuracy index,
place cursors so that they yield
high match strengths, and
verify your accuracy as
described in Step 8 on
page 100.