Can I use a horizontal video with FMV?

[SudaratKungsaranuwat]

Hello everyone,

I took a video using Garmin virb ultra 30 mounted in front of the car.

Then I made the video into MISB video using Multiplexer GP tool.

The problem is that I cannot calculate the proper corner coordinates.

I see everyone use FMV Add-in with the videos from a drone,

so I think maybe FMV Add-in only works with the videos from a drone?

Can I use it with a horizontal video?

Thank you in advance,

Sudarat

[CodyBenkelman]

Sudarat

The short answer is yes.  Have you tried it?  If you tried and something failed, can you share your metadata file?

Longer answer:  

You are correct that, logically, you can't calculate the four corners (on the ground) since the upper corners may be above the horizon.  But the Multiplexer should run - so if it failed, there must be a different problem in your metadata.

Now, to make it usable, what I would recommend is adding an artificial value in the metadata file for Sensor Relative Elevation Angle, e.g. perhaps -30 degrees, to force the software to process the video as if the four corners were *not* above the horizon.  This should result in a video footprint that you could think of as showing "the realistically usable region observed in the video" as opposed to the literal four corners of the image. In reality, if the upper corners are above the horizon, the footprint technically extends to infinity, but realistically you won't see anything of value in the video more than a few hundred meters away...

If that doesn't make sense, let me know 

Cody B. 

[SudaratKungsaranuwat]

Hello Cody,

Thank you so much for your advice.

I have tried it with the metadata attached below.

Dropbox - metadata10.csv 

(Sensor Relative Elevation data from your recommendation)

The result MISB video looks incorrect. The length in the video is not equal to the length on the real ground

and the mark point in the video is not at the same place on the real ground.

I am not sure about an average elevation, I heard that the accuracy of the frame coordinates depends on the accuracy of the average elevation. How can I fill the proper average elevation?

[CodyBenkelman]

Sudarat

The accuracy of projecting a video footprint onto the ground will depend completely on the accuracy of the input data, e.g., the HorizontalFOV, PlatformHeading, PlatformPitch etc. must have correct values.  If any values are approximate (e.g. my suggestion to introduce an adjustment through SensorRelativeElevation) then the resulting video footprint will only be an approximation.  I should have made that clear - but note based on the specific sensor you have, and the oblique angle of your video, I would not expect you will be able to make highly accurate measurements (either size of objects or XY location on the ground)

Regarding the "Average Elevation" value that you enter, for your case you will want to enter "0" and make sure that your SensorAltitude represents height in meters above ground.  Your file shows "-11," so that negative value may be causing you problems (is this ellipsoidal height, from GPS?).  

Note if you have not downloaded the user document in the last 10 days, please get a new copy from esriurl.com/FMV132Manual.  We have updated the documentation specifically regarding the multiplexer and the SensorAltitude value - however, your case (a mobile vehicle with a FIXED SensorHeightAboveGround) is the simplest case, so you do not need to input ground elevation values.

[SudaratKungsaranuwat]

Hello Cody,

Thank you a lot. You made me more clear about Multiplexer tool.

And yes, my sensor altitude data are Ellipsoidal height from GPS.

I tried entering "0" for the average elevation with the metadata in my last reply,

but the result MISB video does not have the frame outline.

so I convert it to Orthometric height as attached below.

Dropbox - metadata16.csv 

This time can I enter "10" for the average elevation?

Besides, I am a little doubt about FIXED SensorHeightAboveGround. It is same as SensorAltitude, right?

You said that in my case, I do not need to input ground elevation values.

So I can delete a SensorAltitude field from the metadata file?

Or maybe I should enter "0" for all values in a SensorAltitude field?

[CodyBenkelman]

Sudarat

please review the documentation on the Multiplexer in http://esriurl.com/FMV132Manual 

Although the MISB specification defines SensorAltitude as orthometric height, our Multiplexer requires height above ground (the input field must be labeled SensorAltitude).  If your camera is 1.6 meters above the ground, enter 1.6 for SensorAltitude  and 0 for AverageElevation.

Cody B.

[SudaratKungsaranuwat]

Thank you a lot for your help, Cody.

[ZaraCarman]

This blog post might be useful https://community.esri.com/community/gis/imagery-and-remote-sensing/blog/2017/07/05/garmin-virb-came...