This article explain what has to be considered while recoding video to use with the laserscan.
The end part describes how to position the calibration rings or the calibration points.
Instructions
Range of operation
• Investigation of pipe line systems, which have to satisfy
high demands on material stability.
– Hydropower plants (stability examination of high
pressure pipes)
• Warranty assessment of high performance drainage
systems for objects like…
– Tunnels and bridges
– Highways
– Airport Runways
Prior to the survey
• Pipe cleaning: removal of floating deposits
• Removal of encrustations to reduce light reflexions on
pipe wall or pipe ground
• Block water flow in order to get the pipe ground visible
Run the survey
Prior to the scan
• Center camera head
• Set Laser ring diameter to 75% of image height
• Set recording format to MPEG2 in order to increase
accuracy of measuring results
• Place the whole length of the calibration bar within the
camera view angle
• Cover the manhole in order to avoid light intrusion at the
beginning of recording a video clip
During the scan
• Switch off the light and text display: only the laser ring
must be visible
• Increase the light intensity of the laser ring at larger
diameters accordingly
• Decrease image luminosity in order to get disturbing red
sparks disappeared
• Scan with a constant low speed (max. 17 cm/sec) in
order to avoid jerky movements of the camera head.
• Keep the camera head centered during recording
• Record a sequence showing the entire calibration bar
(100 mm - 600 mm)
Center the camera
Scan procedure
Speed <= 17 cm/sec
Record calibration bar (horizontal)
Record calibration bar (vertical)
Calibration bar:
scale invisible
Calibration bar:
scale visible
Laser ring with light intrusion
Laser ring with light reflections
Laser ring too big
Laser light too weak
Laser ring not centered
Water flow not blocked
Settings: OK
Set calibration points
Show calibration rings
After the scan
Multi-Laser; scan pipe deformation
Multi-Laser; measure pipe deformation
