• Ultraviolet Photography
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Drones

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#41 Andy Perrin

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Posted 08 January 2019 - 16:26

I’m just trying to understand why the NIR is coming out blue and not red.

#42 UlfW

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Posted 08 January 2019 - 17:18

It is likely due to the white balance.
I tried the same with my soldering iron.
Just as 850nm-filtered images the response was identical for all three RGB-channels when the NIR image was dominant.
If the environment has a lower colour temperature and is used for the white balance it will shift the hot tip colour into blue.

Set temperature 350°C:
Attached Image: Screen Shot 2019-01-08 at 17.37.43 copy.jpg

Set temperature 400°C:
Attached Image: Screen Shot 2019-01-08 at 17.37.32.png

Set temperature 450°C:
Attached Image: Screen Shot 2019-01-08 at 17.37.20 copy.jpg

All white balanced against the not so hot tube at the bottom, reflecting some of the indoor light.

Edited by UlfW, 08 January 2019 - 17:20.

Ulf Wilhelmson
Curious and trying to see the invisible.

#43 Andy Perrin

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Posted 08 January 2019 - 18:20

Interesting. Yes, I see.

#44 WiSi-Testpilot

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Posted 04 March 2019 - 00:09

Here in Germany we had a lot of sun in the past week, so I took some pictures with my copter. The pictures are full spectrum, visual, UV and NIR. In the lower part are four oaks on the roadside, casting their shadows on a field. The third tree from the left still bears its old foliage. He was heavily attacked by the oak processionary moth (Thaumetopoea processionea) last summer. I will observe the trees during the year.
Best regards,
Wilhelm

Full Spectrum, 1/1000s, F/5.6, ISO-100, SELP1650
Attached Image: Full_Vier_Eichen_27_2_2019.jpg

Vis, 1/500s, F/5.6, ISO-100, SELP1650, Heliopan Digital UV/IR Cutfilter
Attached Image: Vis_Vier_Eichen_27_2_2019.jpg

UV, 1/60s, F/2.8, ISO-2000, SEL 20mm 2.8, SEL20F28, Baader U Filter
Attached Image: UV_Vier_Eichen_27_2_2019.jpg

NIR, 1/200s, F/6.3, ISO-100, SELP1650, Green.L 760 nm Filter
Attached Image: IR_Vier_Eichen_26_2_2019.jpg

Edited by WiSi-Testpilot, 04 March 2019 - 08:25.


#45 WiSi-Testpilot

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Posted 08 December 2019 - 17:16

Fawn search and rescue by multicopter/drones is usually made with thermal cameras. The fawns are hidden in the fresh high grass and not visible with a camera for visual light. However it appears as a bright spot in a thermal image. The problem is that other objects heated by the sun such as molehills or free areas also create a bright spot. This leads to misinterpretation. Therefore, some pilots have a vis-camera on board too.
Now my idea is to replace the grass of the vis-video feed by the thermal feed. The necessary chroma keying is possible with a Nvidia Jetson Nano computer in real time. So only the relevant grass appears as a thermal image and it should be easier to identify fawns versus other objects. The advantage opposite to two separate video feeds is that the pilot has to observe one display and only one downlink is needed.

The image shows a picture in picture presentations of a thermal image, which is only visible on the grass. On the green cardboard a heat imprint of the palm of my hand is visible for test purpose.
Attached Image: ChromaKeying_7_12_2019.jpg

The second application is an onboard NDVI calculation. This is my first NDVI image test taken from the warm living room looking outside. The full screen image was created by the following calculation: NDVI = (NIR-Vis) / (NIR + Vis). The brightness should correlate with the health of the vegetation. The algorithm could also be tested for fawn rescue, then of course with a NIR or Vis camera and a thermal imaging camera. The overlap is not perfect, because the cameras lay on the table. Now I have to mount them all and will program a color look up table, so that the colors change from red (for bad vegetation) to green (for good).
Attached Image: NDVI_Test_8_12_2019.jpg

This are the two input images.
Attached Image: Vis_NIR_NDVI_Test_8_12_2019.jpg

Best regards,
Wilhelm

#46 Andy Perrin

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Posted 09 December 2019 - 02:16

Quite interesting. Using a red-green color scheme would be a mess for people with red:green deficiencies like me. I would prefer blue:yellow.

#47 WiSi-Testpilot

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Posted 09 December 2019 - 09:20

View PostAndy Perrin, on 09 December 2019 - 02:16, said:

Quite interesting. Using a red-green color scheme would be a mess for people with red:green deficiencies like me. I would prefer blue:yellow.
Thank you for the information. So I will create both CLUTs.
I’m waiting for sun to make better images.
Best regards,
Wilhelm

#48 Timber

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Posted 10 December 2019 - 14:10

View PostWiSi-Testpilot, on 19 October 2018 - 20:33, said:

I'm afraid that I get problems with non-e-mount lenses on the copter. Therefore my next steps are another filter and a gimbal. Furthermore the pancake is light and seems good for NIR above 900 nm.
Sigma 30mm f2.8 DN
I had good success with that lens in (near)UV. It's AF, light and small.

#49 WiSi-Testpilot

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Posted 10 December 2019 - 18:00

View PostTimber, on 10 December 2019 - 14:10, said:

Sigma 30mm f2.8 DN
I had good success with that lens in (near)UV. It's AF, light and small.
Thank you for the information. I will have a look at the lens.
In #44 I wrote, that I’m using a Sony SEL20F28, but hat is not correct. It is a Sony Sel16f28. It is very light too. Furthermore I’m using the Noflexar 35/3.5, but only at the ground. I have attached a few images. The UV image of the Löwenzahn (Pusteblume) was made with the Sel16f28, the bees with the Noflexar, both with the Baader U filter.
Best regards,
Wilhelm

Attached Images

  • Attached Image: Pusteblume_UV_mod.jpg
  • Attached Image: Pusteblume_UV_org.jpg
  • Attached Image: Pusteblume_Vis.jpg
  • Attached Image: Biene_DSC06083m.jpg
  • Attached Image: Biene_DSC06087m.jpg


#50 WiSi-Testpilot

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Posted 12 July 2020 - 07:45

A picture from yesterday. There were greenish hotspots in the picture. So I converted it to black and white.
I will repeat it also with NIR and Vis.
Have a nice day,
best regards,
Wilhelm

Baader U, Sony Alpha 6000, Sel16f28, f/2.8, ISO 3200, 1/40sec, no gimbal

Attached Image: Teich_11_7_2020bw.jpg

Edited by WiSi-Testpilot, 12 July 2020 - 07:47.


#51 colinbm

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Posted 12 July 2020 - 08:03

Good shot, & I like the trees showing differences in their colours in UV.
Pity the UV fogs the distance in the image though.

#52 UlfW

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Posted 12 July 2020 - 11:57

Sometimes when I have leakage after the filter in lenses and lens mounts, that can cause local greenish spots or veils.
You might want to check for such problems by scanning with a strong flashlight or pointing laser over possible entry points, while observing the live view at a high ISO-setting on the camera.
Ulf Wilhelmson
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#53 Cadmium

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Posted 12 July 2020 - 23:58

WiSi, great UV drone shot!

#54 WiSi-Testpilot

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Posted 13 July 2020 - 12:47

Thank you for your kind answers. Ulf, I did not yet find a leak.
We got a lot of rain during the past weeks. So the vegetation looks very fresh. Therefore I repeated the flights today. After the flights i took an UV-photo of a butterfly. Because I don’t know the name of the flower, I show a vis image too.
The pictures are only resized.
Best regards,
Wilhelm

UV_DSC08282
Baader U, Sony Alpha 6000, Sel16f28, f/2.8, ISO 3200, 1/60sec
Attached Image: UV_DSC08282.jpg

Vis_DSC07993
Sony RX0, f/4, ISO 125, 1/320sec
Attached Image: Vis_DSC07993.jpg

NIR_DSC08112
HOYA R72, Sony Alpha 6000, Sel16f28, f/2.8, ISO 100, 1/1600sec
Attached Image: NIR_DSC08112.jpg

Butterfly_DSC08366
Baader U, Sony Alpha 6000, Sel16f28, f/2.8, ISO 3200, 1/60sec
Attached Image: Butterfly_DSC08366.jpg

Vis_DSC08055
Sony RX0, f/4, ISO 125, 1/800sec
Attached Image: Vis_DSC08055.jpg

Edited by WiSi-Testpilot, 13 July 2020 - 13:18.


#55 Andy Perrin

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Posted 13 July 2020 - 18:24

I love these drone photos! The UV shows the reflection of the trees in the water much better than the other two, although the infrared's dark water also looks pretty in a different way.

#56 WiSi-Testpilot

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Posted 25 July 2020 - 17:53

Thank you, Andy.
Attached are two IR images and a vis image of the pond from July 22nd. I will try to create a four season collection. Summer is the most difficult because it is often to hot to fly and the vegetation looks dry. But everything is fresh this year.
Best regards,
Wilhelm

Flir Vue Pro R 640
Attached Image: 20200722_163004_8b.jpg

Flir Vue Pro R 640
Attached Image: 20200722_163010_8b.jpg

Sony RX0, f/4, ISO 125, 1/160 sec
Attached Image: Teich_22_7_2020_DSC08292.jpg

Edited by WiSi-Testpilot, 25 July 2020 - 17:54.


#57 WiSi-Testpilot

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Posted 21 February 2021 - 09:37

Because it was very nice weather yesterday, I washed the car and tested the UV copter.
Have a nice day,
best regards,
Wilhelm

Attached Image: UV-Adam.jpg

#58 ori333

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Posted 24 February 2021 - 16:43

Fantastic. Air, land....and sea(??).