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UltravioletPhotography

Drones


Cadmium

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WiSi-Testpilot

Andrea, thank you, your explanation and the link are very helpful. So I will look for a good Noflexar 35 / 3.5 and order the adapter.

 

On the copter I would like to use the Sony Pancake SEL 16mm 2.8, because it is very light. At the moment I am mounting the camera on another copter (see picture) so that the camera is closer to the center of gravity and the construction is stiffer. It may last still a few weeks. When the conversion is finished I will show a few pictures. I asked Baader about the U filter. It is not available at the moment. They are making a new batch. I have also ordered a 950 nm IR filter suitable for the pancake.

I am very interested in the comparison between Noflexar 35 / 3.5 and the Sony lens.

Best regards,

Wilhelm

post-210-0-40849200-1540661913.jpg

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For a LIGHT UV-capable lens, my Porst Weitwinkel 35mm/3.5 lens is plastic and does a really nice job of transmitting UV. It is a relabeled version of the Ennalyt 1:3,5/35mm Enna Werke München. It still requires an adapter, but the lens itself weighs 132 grams.
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I asked Baader about the U filter. It is not available at the moment. They are making a new batch.

 

This is very interesting. If you order one and receive it please let me know what the outside markings on the filter say.

Thank you.

 

The only issue you may have with known UV lenses is most will act like telephoto on your copter and you may need to fly higher to get similar angle your used to. Thus adding more actual air space and decrease you image quality in UV. Fortunately they are cheap. So you may be ok with the pancake 16mm vs a 35mm. But you won't really know until you test it.

 

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WiSi-Testpilot

@Andy, thanks for the hint. But I will try to get a Noflexar 35 / 3.5. Is it true that the filter thread is 49 mm as with my Sony pancake?

 

@dabateman, of course I will show a photo and a test.

Tele on the copter is not unproblematic because of the movement. I have not found a suitable gimbal yet. At the moment some people in a German copterforum are designing a stiff and lightweight gimbal.

 

@Cadmium, I can not do that until halloween:-). I'm designing the new camera carrier.

Best regards,

Wilhelm

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I know this is off topic, even off board, so to speak, but this was done with drones, and I thought it was so beautiful, even the accompanying music, that I wanted to post it here.

 

Good one Steve....

I can just imagine this at Salisbury Plain & Stonehenge in the middle........

Cheers

Col

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  • 2 weeks later...
WiSi-Testpilot

Now the Noflexar 35/3.5 and the Exakta/Nex adapter arrived. Thank you again for your explanations. Otherwise I would have had not found the correct parts.

The parts look very good and I made a first comparative test with my pancake SEL20F28. Because I have no fitting filter adapter and the FOVs are different, I laid the filter in front of the lens and made images of the uniform grey November sky, both F/3.5. According to this first test the Noflexar is about one stop better than the pancake, see images. Therefore on the copter I will use the pancake, because it is much lighter, but I like the smaller FOV of the Noflexar. Of course I’ll repeat the test with the Venusfilter.

 

Noflexar 35/3.5

post-210-0-02566600-1541432709.jpg

 

SEL20F28

post-210-0-05868000-1541432732.jpg

 

Furthermore I have mounted the camera at another copter, see image. The distance between the tilt servo and the camera is a bit large. Therefore a few adjustments are to do. This version is more compact and easier to transport than the former setup. The shutter will be released via a Gentwire cable type 21MR. It allows also interval shooting.

post-210-0-17087700-1541432827.jpg

 

It's a bit off topic here, but in January 2017 I took a photo of a halo. While I was flying with the copter, a cloud moved in front of the sun, so that the appearance came out.

post-210-0-33496400-1541432867.jpg

 

Best regards,

Wilhelm

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Wow, I love that sun halo photo with the drone silhouette!

+1 , the appearance of the drone in the image makes it even more special.

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  • 2 weeks later...
WiSi-Testpilot

@ Cadmium, Andra B. and Øivind Tøien.

Thank you for your kind remarks.

 

Drone Landing on the Earth

post-210-0-05407400-1542309242.jpg

Noflexar 35/3.5, F3.5, 1/60 sec., ISO 500

With the Green.L 950 nm Filter the Noflexar has no hot spot up to F16.

Best regards,

Wilhelm

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  • 1 month later...
WiSi-Testpilot

I’m just soldering new electronic speed controllers (ESC) at one of my copters. The ESCs are the latest generation with sine-wave output and field-oriented control. Thereby I have taken a picture with the full spectrum camera and a thermal image of my soldering iron. The temperature was set to 350 degrees Celsius.

Best regards,

Wilhelm

post-210-0-17771000-1546936695.jpg

post-210-0-47057800-1546936710.jpg

post-210-0-33445000-1546936728.jpg

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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:

post-150-0-06991800-1546965656.jpg

 

Set temperature 400°C:

post-150-0-60701900-1546965674.png

 

Set temperature 450°C:

post-150-0-17697300-1546965690.jpg

 

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

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  • 1 month later...
WiSi-Testpilot

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

post-210-0-89492300-1551658846.jpg

 

Vis, 1/500s, F/5.6, ISO-100, SELP1650, Heliopan Digital UV/IR Cutfilter

post-210-0-40438900-1551658890.jpg

 

UV, 1/60s, F/2.8, ISO-2000, SEL 20mm 2.8, SEL20F28, Baader U Filter

post-210-0-78199000-1551658911.jpg

 

NIR, 1/200s, F/6.3, ISO-100, SELP1650, Green.L 760 nm Filter

post-210-0-03019100-1551658877.jpg

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  • 9 months later...
WiSi-Testpilot

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.

post-210-0-13123900-1575825039.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).

post-210-0-25824500-1575825079.jpg

 

This are the two input images.

post-210-0-37409100-1575825154.jpg

 

Best regards,

Wilhelm

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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.
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WiSi-Testpilot

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

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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.

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WiSi-Testpilot

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

post-210-0-47142600-1576000655.jpg

post-210-0-59724000-1576000669.jpg

post-210-0-60482100-1576000687.jpg

post-210-0-66009100-1576000709.jpg

post-210-0-03509400-1576000732.jpg

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  • 7 months later...
WiSi-Testpilot

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

 

post-210-0-75955300-1594539856.jpg

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