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Incorrect video frame footprint for FMV video

Question asked by MervynLotter on Oct 26, 2018
Latest reply on Nov 1, 2018 by MervynLotter

Hi there

 

Through the use of the Cirruas app, I have been able to collect the flight log file as a CSV for use in the Multiplexer GP tool. Given that many drones do not record altitude very accurately, from the app there is an option to correct the take-off altitude before exporting the log file. I do this so my elevation values should be correct. I suspect it determines the tack-off altitude from an image service.

 

In order to create the video frame footprint (frame outline), one needs to include elevation values for the ground surface (or height of drone above ground). In ArcMap one only has the option of specifying the flight altitude while for Pro one can also use an imagery service. I have tried both methods and I still have the same problem. I hope someone can advise me how to fix it?

 

The problem I have is that my video frame footprints are not being accurately located in GIS. In fact they almost never overlap with the actual footprint. The calculated video footprint is always displaying a much larger area to the front of the drone. 

 

I tried looking at this in a scene view and the multiplexed video correctly shows a 'leader-line' or video image center line that is centered in the actual video footprint (not the calculated one).  See below image.

Video image center line

However for this same view, the calculated footprint is way off. The calculated video frame is far from the actual video center line - and it covers a much wider area.

Calculated video image footprint - incorrect

 

Any advice as to what the cause for this error may be?  I suspect it may either be the elevation data or the way the metadata was captured. In Pro I use the Esri Terrain service as my input into the multiplexer tool.

 

The Cirruas app records the below metadata which should be adequate in calculating video image footprints. I include the minimum and maximum values recorded for the above flight in case anything stands out. For example, should Platform Heading Angle and Sensor Relative Azimuth Angle not be in the range of 0-360?

 

MinimumMaximum
UNIX Time Stamp
Platform Heading Angle-178.4176.2
Platform Pitch Angle-19.822.6
Platform Roll Angle-151.1159.1
Sensor Latitude
Sensor Longitude
Sensor True Altitude1487.61551
Sensor Horizontal Field Of View7676
Sensor Vertical Field Of View4848
Sensor Relative Azimuth Angle-183.5351.4
Sensor Relative Elevation Angle-168.2168.2
Sensor Relative Roll Angle-4347.1

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