DJI Thermal Images Processing (converter to .tiff) SOLVED!

[kataluna]

Hello,
I tried several things...
I converted the Thermal images with your program.
I always have same problem with alignment
"some photos failed to align"
Its everytime a different number (83/564; 160/564; 60/564...)
The very first thing that goes wrong is that when I add photos I dont have possibility to choose mult-camera system

KR
Kat

 

[Miro_Rava]

Hello,
I tried several things...
I converted the Thermal images with your program.
I always have same problem with alignment
"some photos failed to align"
Its everytime a different number (83/564; 160/564; 60/564...)
The very first thing that goes wrong is that when I add photos I dont have possibility to choose mult-camera system

KR
Kat

Hi, if you don't have the possibility to choose a multi-camera system it means that your thermal images are in different number with respect to your rgb images, check that before importing them in metashape. also if you find it difficult to align images , try first only with thermal and then with rgb separately (in two different chunks).

it could be the issue that you have taken too few pictures with the thermal camera, remember that the resolution of the thermal camera is very low and also the fov is narrower, this means that you need a higher overlap when you take the pictures in thermal mode.

Let me know if these solutions are helpful, Best regards,
Miro

 

[RotorThingy]

Hi Miro, great work! May I ask how you view your radiometric ortho's once rendered? Are you able to click on a pixel and retrieve the temperature?

 

[Miro_Rava]

Hi Miro, great work! May I ask how you view your radiometric ortho's once rendered? Are you able to click on a pixel and retrieve the temperature?

Hi RotorThingy, sorry for not answering sooner,
If you used metashape to build the orthophoto, after having selected a palette from the raster transform (only for viewing reasons), you can simply hover the mouse over the image and in the far right bottom angle of the window, you should see an index value (this is the temperature in Celsius)

Otherwise, you can save the image as single band tiff and take a look at it using external viewers like imagej ( it is open source an full of functionalities)


Let me know if you manage to view the images!

Best regards,
Miro Rava

 

[Eternal]

The tiff images were just saying "no image" and nothing could recognize them.

 

[RotorThingy]

Thanks Miro, your converter is keeping my room warm processing a few radiometric jpg's, love your work! I see the index value in Metashape but not in imagej, it throws the error "unsupported format or file not found: C:\etc...". I'm guessing that's got something to do with my inability to export the ortho's as single band tiff. I don't suppose you could elaborate on a way to achieve that?
PS. I'm coming to Italy next year, I will buy you a beer. Or a lemonade. Or a sandwich, your choice (c;

 

[RotorThingy]

I have tried the Bioformats image importer in Imagej. It will import the tiff but displays a white image with no radiometric data.

Ideally I'd like to have access to the radiometric stuff in a browser (click a pixel, get the temperature). Has anyone succeeded with that?

Below is a little give back, its a 51 colour raster palette that I use for thermal ortho's in Metashape. Open the code below and save it as a .clr file then open it from "Import Palette" in "Set Raster Transform". You'll get a false colour spread like the pic below. You're welcome (c:

ColorMap 1 1
0 0 0 255
2 0 32 255
4 0 64 255
6 0 96 255
8 0 128 255
10 0 160 255
12 0 192 255
14 0 224 255
16 0 255 255
18 0 255 224
20 0 255 192
22 0 255 160
24 0 255 128
26 0 255 96
28 0 255 64
30 0 255 32
32 0 255 0
34 32 255 0
36 64 255 0
38 96 255 0
40 128 255 0
42 160 255 0
44 192 255 0
46 224 255 0
48 255 255 0
50 255 224 0
52 255 192 0
54 255 160 0
56 255 128 0
58 255 96 0
60 255 64 0
62 255 32 0
64 255 0 0
66 255 0 32
68 255 0 64
70 255 0 96
72 255 0 128
74 255 0 160
76 255 0 192
78 255 0 224
80 255 0 255
82 224 0 255
84 192 0 255
86 160 0 255
88 128 0 255
90 96 0 255
92 128 0 255
94 102 0 204
96 77 0 153
98 51 0 102
100 26 0 51

 

[Miro_Rava]

I have tried the Bioformats image importer in Imagej. It will import the tiff but displays a white image with no radiometric data.

Ideally I'd like to have access to the radiometric stuff in a browser (click a pixel, get the temperature). Has anyone succeeded with that?

Below is a little give back, its a 51 colour raster palette that I use for thermal ortho's in Metashape. Open the code below and save it as a .clr file then open it from "Import Palette" in "Set Raster Transform". You'll get a false colour spread like the pic below. You're welcome (c:

View attachment 177118

ColorMap 1 1
0 0 0 255
2 0 32 255
4 0 64 255
6 0 96 255
8 0 128 255
10 0 160 255
12 0 192 255
14 0 224 255
16 0 255 255
18 0 255 224
20 0 255 192
22 0 255 160
24 0 255 128
26 0 255 96
28 0 255 64
30 0 255 32
32 0 255 0
34 32 255 0
36 64 255 0
38 96 255 0
40 128 255 0
42 160 255 0
44 192 255 0
46 224 255 0
48 255 255 0
50 255 224 0
52 255 192 0
54 255 160 0
56 255 128 0
58 255 96 0
60 255 64 0
62 255 32 0
64 255 0 0
66 255 0 32
68 255 0 64
70 255 0 96
72 255 0 128
74 255 0 160
76 255 0 192
78 255 0 224
80 255 0 255
82 224 0 255
84 192 0 255
86 160 0 255
88 128 0 255
90 96 0 255
92 128 0 255
94 102 0 204
96 77 0 153
98 51 0 102
100 26 0 51

hi RotorThinghy,
sorry for the late response to the previous message, I was doing a trekking up in the Alps and didn't have connection,
If you want to export the tiff, before you need to preserve the temperature data, this is how you do it:

• After the Orthomosaic is built , to view it , click on the ortho panel:

• Then open the Tool Menu à Set Raster Transform: this window will pop up:

Under output bands, in the “expression” field, write: B4 (if you have also rgb images) otherwise B1 (if you have only one band)

also MAKE SURE THAT “Enable Transform” IS CHECKED!

• Click APPLY, then go to Palette (upper left)

(note that the graph you will see displayed will be different from mine)

• Click on the two circling arrows near the AUTO button
• Then click AUTO (you can also manually tweak the temperature range)
• Finally click APPLY

then you can try to export the image like this:

Use these parameters, precisely set the raster transform to index value, the no data value to whatever you prefer (better if it is quite near the other temperature values, otherwise you will have an all white or all black picture) and the tiff compression to none.

this should give you the data in Celsius and be able to view it in imageJ

Let me know if this works.

Also, in order to view the image in a browser and hover over a pixel and have the temperature value, you will have to make some custom code in JS or something else. I unfortunately do not know of an app to view the image as you want that is already made.

Since the produced tiff doesn't maintain the palette but has the data, you can export two different pictures, one with the rgb palette and one with the temperature data, then overlay one on top of the other (with 0 opacity for the temperature one) and be able to hover the mouse on the image and see the palette but also read the data.

(the overlay stuff you can also do it with ImageJ)

Let me know if this helps!
Best Regards,
Miro

 

[Eternal]

My ortho has an area that has wrong temps, -10 to 0 celcius even though it is summer. Any idea what might have caused this? The ortho is 90% correct with temps but that one area bothers me. So close but so far...

 

[jaja6009]

My ortho has an area that has wrong temps, -10 to 0 celcius even though it is summer. Any idea what might have caused this? The ortho is 90% correct with temps but that one area bothers me. So close but so far...

Did you check this by comparing the temperatures in DJI Thermal Tool (Pre TIFF Conversion)?

Are you sure that this is not just metal reflecting the cold sky?

As an example, take the temperature with your thermal camera of the sky (No sun in it, the sun can damage your thermal sensor). Its always colder than the ground.
Metal reflects this colder temperature since it has lower emissivity and higher reflectivity.
Even providing corrections to the parameters, reflective metal is a poor choice for temperature analysis and in thermography classses it is taught to not attempt this at Level I.

And if you do compare the temperature values in DJI Thermal Tool, remember that the radiometric thermal ortho has each pixel's temperature as an average of the temperature values of the pixel for each image it is in. And since every image is at a different angle to the pixel, there will be variations in the temperature of the pixel in each image.

A thermal ortho while being a nice representation for fast viewing of thermal anomalies, it does not replace taking the best image of an anomaly that has the proper focus, range and distance (Pixels on target), and also proper angle and then doing a proper analysis on the single image in DJI Thermal Tool.




The image above was taken in the summer. The black metal caps on the roof are metal and have low emissivity. They are refecting the cold sky and even though the temperature was 75 degrees F at time of capture, they show colder than ambient temperatures with some being ~36 degrees F.

 

[millie.spencer]

Hello,
I try to convert images from Mavic 3 T (EU) but the application tell me the images are not DJI Thermal Images.
I'm on a MacBook with Parallels Desktop.

Thanks for your help!

I'm getting this same error! I tried with both the pre- and post-processed (in DJI Thermal analysis tool) images but kept getting this error. Any solution?