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Author Topic: Thermal orthomosaic - Flir Duo Pro R  (Read 11506 times)

Pkroks

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Thermal orthomosaic - Flir Duo Pro R
« on: July 19, 2018, 09:45:08 AM »
Hi,
I'm trying to create a thermal orthomosaic from imagery captured with the Flir Duo Pro R.

The imagery is captured at 40m AGL, taken using 1sec intervals, flying at speeds of 15km/h, flying along rows of solar panels. Overlap of these images is really high, 80% or more. The final image works out to be a Radiometric Jpeg file containing radiometric data (temperatures for each pixel).

I am looking for a workflow or instructions on how to use this imagery to process an orthomosaic and use a thermal mesh to display as a thermal layer perhaps over the rgb orthomosaic.

The beauty of the Flir duo pro R is that the images are taken at the same time, two lenses and the final RGB imagery once the full photo is extracted from the RJPG becomes 4000x3000 pixels. So it is relatively high. The thermal sensor resolution is 640x512 pixels. According to a few forum posts, I gather you can potentially stitch the RGB, and then overlay the thermal layer (lower resolution so harder to stitch straight up) on top of the surface model?

Please can someone help point me in the right direction to be able to create a thermal orthomosaic from this imagery. I have tried to use pix4d trial version - as they have instructions regarding thermal imagery in their support section, but I would like to use agisoft photoscan, as this is what we use for all our other processing.

I do have other imagery where by I flew the same area at 80m above ground, with 80% overlap and 85% front lap in a grid pattern, pictures every 1second, captured using drone deploy to fly the grid at a consistant speed.

Pkroks

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #1 on: July 23, 2018, 01:59:30 PM »
anybody?

Pkroks

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #2 on: July 25, 2018, 01:03:13 AM »
I have just flown a tiny site today, radiometric jpeg images captured. Total area covered was 11acres.

Flying 65m above ground level. 10ms, I flew a cross hatch pattern using drone deploy as the flight controlling app - (similar to pix4d double grid mission). Total of 442 images were used to attempt an orthomosaic. Both in Pix4d and in Agisoft.

136 images aligned out of 442 images. Settings were on high alignment, reference preselection, 40 000, 10 000. This was using the RGB images that are extracted as full photos (4000x3000 pixels).

Camera is the FLIR DUO PRO R. 1 picture every second (radiometric jpeg, so 1 jpg and 1 tiff image once extracted to full photos).

I have absolutely no idea what is going on and what I am doing wrong.
« Last Edit: July 25, 2018, 01:05:32 AM by Pkroks »

mwillis

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #3 on: July 25, 2018, 02:26:56 AM »
Hi Pkroks, I have had the same problem.  You won't hear me say this very often but Pix4D is the only app that I've found that will reliably build Flir data.

Since you also have the RGB data, you can build that in Photoscan and then replace the path with that of Flir imagery.

Hope that helps.

Pkroks

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #4 on: July 25, 2018, 09:39:19 AM »
Hi Pkroks, I have had the same problem.  You won't hear me say this very often but Pix4D is the only app that I've found that will reliably build Flir data.

Since you also have the RGB data, you can build that in Photoscan and then replace the path with that of Flir imagery.

Hope that helps.

Thanks for the reply. In this situation even the rgb will not align when the overlap is incredibly high...?

Please can you explain what you mean about changing the path.

3DWinter

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #5 on: July 26, 2018, 01:09:03 AM »
You are working with the radiometrickJPEG!? I tried to work with just the jpeg from the visible channel or tiff from the thermal, and in both cases, Photoscan cannot retrieve the focal-length.  Can you confirm that Photoscan is retrieving the correct focal length for the radiometric jpeg? I wonder what would that look like since these are two different cameras with different focal-length?

3DWinter

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #6 on: July 26, 2018, 07:16:18 PM »
you might have an interest in a parallel thread.
http://www.agisoft.com/forum/index.php?topic=9396.0

Pkroks

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #7 on: July 26, 2018, 10:37:05 PM »
You are working with the radiometrickJPEG!? I tried to work with just the jpeg from the visible channel or tiff from the thermal, and in both cases, Photoscan cannot retrieve the focal-length.  Can you confirm that Photoscan is retrieving the correct focal length for the radiometric jpeg? I wonder what would that look like since these are two different cameras with different focal-length?

Hi, the exif data does not seem to contain the focal length from the camera, and searching online I can't seem to find it anywhere. I called FLIR agents yesterday to find out about this and haven't had a response yet.

My model is the FLIR DUO PRO R 640 13mm Dual Sensor - lens 13mm, Frame rate is 30hz. The visible sensor resolution is 4000x3000 and field of view is 56x45 degrees.

Not sure of where I can calculate or find the focal length?

I flew another flight today of a new site, again, the imagery only aligns in 5% of the images. Have not yet tried the thermal tiff files.

3DWinter

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #8 on: July 27, 2018, 04:52:18 AM »
I would not use the radiometric jpeg that is a combined file mess.

Instead only work with the Visible (JPEG) and thermal (Tiff) separately. If you can find a way to use exiftool you will find the focal length to be there, but as you saw in my post from last night, FLIR put the tag in the wrong location of the metadata. More so the manual specifies the focal length to be 4mm while deep in the image metadata it says 8 mm (for the visible).

I also have a ticket with FLIR on these issues as of July 19. I have asked to upgrade the ticket to their higher technician, TIER 2, with no response yet.

A question to Photoscan, can you manual add focal length to the camera for all images?

Pkroks

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #9 on: July 27, 2018, 09:59:09 AM »
I would not use the radiometric jpeg that is a combined file mess.

Instead only work with the Visible (JPEG) and thermal (Tiff) separately. If you can find a way to use exiftool you will find the focal length to be there, but as you saw in my post from last night, FLIR put the tag in the wrong location of the metadata. More so the manual specifies the focal length to be 4mm while deep in the image metadata it says 8 mm (for the visible).

I also have a ticket with FLIR on these issues as of July 19. I have asked to upgrade the ticket to their higher technician, TIER 2, with no response yet.

A question to Photoscan, can you manual add focal length to the camera for all images?

I think you can add the focal length. I tried this last night and it improved the alignment straight away from like 5% to 90%. I just put 35mm as the focal length. Perhaps 8mm would be better. I just went to Tools - Camera Calibrations - Focal Length

So you recommend to capture the data as RGB Jpg files, and Radiometric tiff files, and then use exif tools to modify the metadata to include the focal length? Instead of actually capturing the single RJPEG file.
« Last Edit: July 27, 2018, 10:44:23 AM by Pkroks »

3DWinter

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #10 on: July 27, 2018, 07:33:06 PM »
I am trying a few steps myself.  First, the thermal camera focal length as of now is 8 mm, definitely not 35 mm. The thermal is 19 mm.
Because the visible and the thermal cameras are so different (number of pixels, sensor size, focal length), I am not sure what is the value for mosaicing of the sandwiched combined images (radiometricjpeg).

For now, I am processing them separately.  We could check with the Photoscan team if they have instructions on how to use the alignment of the camera (lat, long, alt, pitch, roll, yaw) derived and refined form the visible imagery to process the thermal imagery.

cheers,

Pkroks

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #11 on: July 29, 2018, 04:36:13 PM »
I am trying a few steps myself.  First, the thermal camera focal length as of now is 8 mm, definitely not 35 mm. The thermal is 19 mm.
Because the visible and the thermal cameras are so different (number of pixels, sensor size, focal length), I am not sure what is the value for mosaicing of the sandwiched combined images (radiometricjpeg).

For now, I am processing them separately.  We could check with the Photoscan team if they have instructions on how to use the alignment of the camera (lat, long, alt, pitch, roll, yaw) derived and refined form the visible imagery to process the thermal imagery.

cheers,

Hi, I spoke to FLIR support and they have advised me the thermal sensor focal length is 13mm.

I used the following settings -

Align - Generic preselection, high alignment, adaptive camera model fitting.
Dense cloud - Ultra high
DEM - using dense cloud
Ortho - Using dem

Everything says completed successfully, the imagery aligns and the DEM loads in the model space and I can view it no problem. But when i select to view the ortho it just shows blank.

I have also tried to export the ortho and it says completed successfully, I go to the folder it's located in and the file is not there. I look at quick access in explorer and it lists the file as the last file I used. But it can't locate it.

Not sure why it is doing this? I have tried to select various options for the export of the ortho and tried under the batch processing to export and it won't save. Not sure why. I have 90gb free on the harddrive.

Chandru

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #12 on: July 31, 2018, 11:10:48 AM »
Hi,
   How to ortho mosaic in thermal image .

Pkroks

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #13 on: August 07, 2018, 12:24:57 AM »
So after weeks of frustration with AGISOFT I decided to get a pix4d trial.

In 3 days I have managed to export a thermal orthomosaic.

Anyone care to assist further with this? Don't particularly want to have two software licenses when one should really be enough.

Toll

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Re: Thermal orthomosaic - Flir Duo Pro R
« Reply #14 on: September 21, 2018, 11:37:54 PM »
I'm not sure if this information will help you. But we are successfully using agisoft for thermal ortho photo using flir camera for DJI.

We save as tiff ( I think it is radiometric because the photo preview on windows is all black, but when loading into GIS, it is a raster with cell values in~7000).

We use raster calculator in photoscan and apply the conversion to degrees Celsius as per info on flir website. 

This gives all photos in photoscan colour, which we then proceed as normal for Align/cloud/ortho