videoscopes
SEE MORE IN 3D
Even with advanced stereo
measurement capabilities,
every measurement’s
precision will still depend
on the precision with
which the user sets a
reference point or plane. In some cases,
setting these parameters is
straightforward. However, there are many
situations where this is more challenging.
Examples of this include scenes with
complex shapes, difficult lighting
conditions and irregular surfaces.
Seeing the precise shape of critical
components becomes easier when using 3D
modeling. Being able to look at various 3D
views in addition to 2D images helps users
enhance knowledge of the target. It can
also provide powerful renderings such as
reference planes, which allow users to
quickly understand protrusions and
depressions with distance values and colorcoded
3D models.
To provide maximum confidence in the
placement of reference and measurement
points, there is also the possibility to use a
real-time connection between 2D and 3D
views. This means, for example, that when
a user changes a pixel selection in the 2D
view, the software automatically updates
One way to compensate for the increase
in error range is to determine the physical
variances of each lens and incorporate
these parameters into the measurement
algorithm. Capturing this relationship
between the scope unit and the stereo tip
adaptor increases the measurement
accuracy significantly.
Another way is to improve the user’s
ability to select the desired measurement
point. Most of the image features in gas
turbines are relatively similar, so providing
magnification in the region of interest
would reduce the chance of incorrect
selection.
The IPLEX NX industrial videoscope
from Olympus employs both techniques to
enhance measurement accuracy. The oneto
one matching between the scope unit
and the stereo tip adaptor allows the
measurement algorithm to reduce the error
range. The optimized optics and image
sensor enable users to select the best point
for the best result.
AEROSPACETESTINGINTERNATIONAL.COM // SHOWCASE 2020 125
depth of field. These expanded capabilities
mean that it is possible to measure defects
from farther away compared to
conventional videoscopes – and therefore
gain a higher probability of detection. In
addition, the larger inspection area
provides users with another important
benefit: speed. With some videoscopes it
can take several images to view the
complete region of interest. Having the
ability to measure from a greater distance
results in faster inspections and
measurements (see figure 1).
STEREO-ACCURACY
When using the stereo measurement
function, the user first captures stereo
images at a suitable distance and then
selects a measurement point on one of the
two images. The videoscope then
automatically chooses a matching pixel on
the other stereo image. The measurement
algorithm determines the 3-dimensional
position of the matched pixels based on the
change in perspective. As more
measurement points are selected, results
such as length, area and depth can be
calculated. As the tip-to-target distance
increases, the range of error would also
increase. This phenomenon is generally
inherent to stereo measurement systems.
“Modern high-end videoscopes have
moved far beyond basic imaging”
1b
/AEROSPACETESTINGINTERNATIONAL.COM