Inspection High Speed High Intensity Photogrammetry Data ... · 3 Specifications for OOS surveys...
Transcript of Inspection High Speed High Intensity Photogrammetry Data ... · 3 Specifications for OOS surveys...
Inspection – High Speed High Intensity Photogrammetry
Data for Out of Straightness Fugro Survey Limited Aberdeen
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Fugro
SeaStriper
Fugro Survey
Limited
Aberdeen
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Specifications for OOS surveys are constantly
increasingly comprehensive and onerous on the
survey contractor to collate and present high quality
and high quantity data.
In response to the ever increasing demands on the
survey teams to comply with these specifications
Fugro have developed a suite of hardware and
software tools to enable this to occur efficiently.
OSS Surveys
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Currently OOS Data is collected from dual head Multi-
Beam Echo Sounder data and high accuracy
positioning sensors or odo wheels in contact with the
pipeline. This requires very highly skilled ROV pilots.
Current OOS data deliverables are of the top of pipe
from generally manually picked from the data set. The
positions and depth provided is raw and non-tidally
corrected.
The interval of the top of pipe reporting is ever
decreasing.
There have been many advancements in Multi-Beam
Echo Sounder technology determining the top of pipe
can still be a very onerous task and open to
interpretation.
ROV MBES trenched pipeline profile data
ROV MBES trenched pipeline data
Current data collection
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The SeaStriper system is a Fugro proprietry high
resolution optical survey solution.
SeaStriper collects an accurate 3D point cloud of
complex subsea infrastructure using non-contact,
vision and laser technologies.
SeaStriper is a precise, robust and adaptable subsea
survey system designed especially for subsea pipeline
inspection.
SeaStriper data
MBES Data
Fugro SeaStriper
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SeaStriper has the following components:
Two pairs of calibrated machine vision cameras
Two green laser stripers (150 mW Class IIIb)
Camera control unit (CCU)
Interconnecting cables (CCU to ROV)
Starfix.NG SeaStriper Solution
ROV Requirements
• INS Positioning Solution
• Gigabit Ethernet & Trigger Line
• 12-30v DC Power
Skid Mounted
Bar Mounted
SeaStriper Components
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ROV Multi-beam Echo Sounder Calibrations require
approximately 4 hours to acquire and process to allow
for operations to commence.
Seastriper takes approximately 10 minutes of
observations by the cameras on a target table at
varying altitudes and headings followed by 10 minutes
of computer number crunching. After this the system
is ready to undertake OOS survey operations.
Calibration
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As seen in the data examples the density of raw data
allows for clearer identification of the pipe line and the
top of pipe compared to Multi-Beam Echo Sounder
data.
Data examples
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Combined Data Set
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The SeaStriper data is handled as a pseudo MBE
device.
Once all the data is present in the database the Top of
Pipe (TOP) is automatically picked from the
SeaStriper data in the Starfix Suite using Fine Pick,
little manual work is required on this due to the highly
dense and precise data.
If the SeaStriper is imaging the seabed adjacent to the
pipeline then the Seabed Adjacent Level (ADJ)
markers are also assigned using the previously
defined TOP as reference.
If only the pipeline is being imaged by the SeaStriper
then no seabed markers can be assigned to this data.
The TOP is injected into the Reson MBES data and
the Natural Seabed Level (SBL) assigned using the
Reson MBES data.
Automated
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Accuracy
FSLTD used a section of data to model in Leica Cyclone. This was acquired using FCV3087 with
SeaStriper running at 8Hz.
Distance between ‘stripes’ along pipeline: 20 – 40 mm
Distance between data points on each stripe: 2 – 4 mm.
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The SeaStriper data was also modelled by best fitting
a cylinder to the point cloud at regular intervals along
the data set.
This allowed FSLTD to compare SeaStriper measured
OD against client supplied, as well as pipe position
and depth.
Client Supplied OD: 0.363m
SeaStriper measured OD: 0.359m (Min: 0.354, Max: 0.363)
Accuracy
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Project Trial – OOS
There are two bottle-necks in the current processing workflow when working with MBES data alone;
cleaning the data and assigning the pipeline marker. These two processes require time-consuming
manual intervention to complete, to varying degrees, depending on the quality of the acquired data.
The SeaStriper does not use acoustic data therefore the amount of noise present in the data is minimal
and generally does not require manual cleaning.
The automatic pipeline picking routine in Sfx.Edit requires a substantial amount of data points on the
pipeline in order for the algorithm to successfully place the pipeline marker, Seastriper enables this.
When this is not successful, the alternative is to manually assigning the marker for each cross profile
which is a time-consuming process.
The increased precision and density of the SeaStriper data (over MBES) results in the pipeline being
successfully automatically picked and therefore little manual work is required.
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Top of Pipe from MBES
Top of Pipe from SeaStriper
Project Trial – OOS
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Differences between MBES, ODO and SeaStriper
Project Trial – OOS
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Differences between MBES, ODO and Seastriper
Project Trial – OOS
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Time Saving
The below statistics are calculated for one hour of data surveying at 600 m/hr and processing MBES at
1m intervals.
In summary, utilising SeaStriper on a 28 days ‘standard’ project with three processors on the vessel
results in 9.3 man days of time saved, this is due to the increased density and precision of the data, over
MBES, which allows more automated post processing routines to be utilised.
This frees the senior processor to fully manage the reporting rather than being the pipe expert. The data
is also available to the client sooner.
Processing Navigation
[Mins]
Sfx.Proc
Cleaning Data [mins]
Sfx.SwathEdit
Assigning markers [mins]
Sfx.Edit
Total time
[mins] Speed Gain
Option 1
2x MBES 10 5 45 60
1.5 Option 2
2x MBES & 2x Seastriper 21 5 15 41
3 processors 36.0 Man hours per day
28 day project
(70% acquisition time) 19.6 Acquisition days
Option 1 705.6 Project man days
Option 2 482.2 Project man days
223.4 Man hours saved
9.3 Man days saved
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• With the requirement for high specification OOS
surveys new tool need have been developed to
achieve the requirement.
• Increase in speed and accuracy allowing for
additional time savings.
• Additional information can be provided and
increased statically analysis
• Future development to the system is only
restricted to what we can ‘see’
Conclusion
Fugro Survey Limited
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