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New Jersey Botanical Garden Today 04032021

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#1 ori333

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Posted 04 April 2021 - 04:14

Fantastic Day.

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#2 Stefano

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Posted 04 April 2021 - 04:17

Very nice. The UV images look a bit soft to me, but nice comparisons.

#3 Bernard Foot

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Posted 04 April 2021 - 08:04

Can you explain your rig and what we're seeing?
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#4 dabateman

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Posted 04 April 2021 - 14:44

You should code in either greyworld switch for -awb or use -cfx 128:128. Either will give you a nicer monochrome image than all magenta. Unless you like all magenta, the US votes that way with 49% blue and 49% red, sadly only 0.3% went green.

#5 ori333

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Posted 05 April 2021 - 01:46

View PostBernard Foot, on 04 April 2021 - 08:04, said:

Can you explain your rig and what we're seeing?

Natural Sunlight.
Two Raspberry Pi HD cameras connected to an NVIDIA Jetson.
One camera is RGB, the other is a modified camera by MaxMax with a quartz lens and a filter stack to only pass UV.

Photos taken simultaneously (as jpegs unfortunately, not raw)

This was taken in video mode so shutter speed is 1/30 seconds.

#6 ori333

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Posted 05 April 2021 - 15:09

View Postdabateman, on 04 April 2021 - 14:44, said:

You should code in either greyworld switch for -awb or use -cfx 128:128. Either will give you a nicer monochrome image than all magenta. Unless you like all magenta, the US votes that way with 49% blue and 49% red, sadly only 0.3% went green.

Thanks.
Those images are jpegs from the NVIDIA Jetson. I'll try to get the RAW from the Jetson next weekend, and record some video too.

#7 ori333

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Posted 05 April 2021 - 15:31

EDITOR'S NOTE: Valentin -- I have embedded your second set of videos here. And the first set is embedded below in Post #11. There is some limit on the number of embeds per post, it seems. -- Andrea B.


Here is some video of the video.
https://youtu.be/IyUiIejDyUA
https://youtu.be/HwU1suYJvBY

And some "in the making video"
https://youtu.be/V2JUORJs1l4
https://youtu.be/4E9yf6UJv30

Embeds of the second set of videos.



#8 ori333

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Posted 05 April 2021 - 15:39

And as always feedback appreciated.

#9 ori333

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Posted 05 April 2021 - 19:10

View PostStefano, on 04 April 2021 - 04:17, said:

Very nice. The UV images look a bit soft to me, but nice comparisons.
Yes, thank you.
I will try to do better next time.
I had no control of the exposure time on this one and need better placement of the monitor to see what I'm taking a picture of. Sunny day with a lot of glare.

Edited by ori333, 05 April 2021 - 19:10.


#10 Andrea B.

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Posted 06 April 2021 - 20:10

Thank you for showing us this awesome set-up of your experimental gear.
It takes time to refine the techniques -- especially when all the gear is new and untested,
but you are definitely getting there! It's very cool to shoot UV & Vis simultaneously.

I agree with the suggestion to subdue the false colour on the UV side.
Use B&W or substantially reduce the saturation in the red range.
Then it will be much easier to get the distance from the subject correct
if details are not obscured by the colour.

A small umbrella or some kind of shade over the monitor will help.
Or even a cloth cover over your head and the monitor like in the olden days. La!

Wow! Those e-ribbons off the Raspberry Pi-Cam boards are *huge* !!

Any particular reason why you went with the Nvidia Jetson? I'm just curious.

Also what is the peak of the UV-pass filter? I can't judge the color here because it isn't raw.
I'm guessing between 350-365 nm?
Andrea G. Blum
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#11 Andrea B.

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Posted 06 April 2021 - 20:24

Valentin -- I embedded the second set of your videos above in Post #7.
Then I hit a limit on the number of embeds per post.
So the first two are embedded here in this post.

UV/Vis Simul-Vids == so cool !!



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#12 Andrea B.

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Posted 06 April 2021 - 20:32

[This is my 3rd post in a row. Someday I will learn how to consolidate posts.]

V -- I just wanted to say that when I saw the photos in the first post above, I immediately recognized the New Jersey flowers that I used to happily photograph every spring. (I miss New Jersey !!) The nice yellow flower with the UV-dark bulls-eye is Ranunculus ficaria, which is one of the early blooming flowers useful to all us UV photographers for testing gear. You should also be seeing some dandelions blooming. They are also good subjects with their diffuse UV-dark centers.
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#13 ori333

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Posted 06 April 2021 - 22:27

View PostAndrea B., on 06 April 2021 - 20:32, said:

[This is my 3rd post in a row. Someday I will learn how to consolidate posts.]

V -- I just wanted to say that when I saw the photos in the first post above, I immediately recognized the New Jersey flowers that I used to happily photograph every spring. (I miss New Jersey !!) The nice yellow flower with the UV-dark bulls-eye is Ranunculus ficaria, which is one of the early blooming flowers useful to all us UV photographers for testing gear. You should also be seeing some dandelions blooming. They are also good subjects with their diffuse UV-dark centers.

Thank you. I was just thinking of where should I go next? Out of the entire botanical garden there were only those three that I found to be in bloom.
Maybe I should drive a little south next weekend?
On my list is Duke Farm, NJ Botanical Garden, Rutgers Gardens but don't know when is the best time to go. Any suggestions for April?

#14 ori333

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Posted 06 April 2021 - 22:40

View PostAndrea B., on 06 April 2021 - 20:10, said:

Thank you for showing us this awesome set-up of your experimental gear.
It takes time to refine the techniques -- especially when all the gear is new and untested,
but you are definitely getting there! It's very cool to shoot UV & Vis simultaneously.

I agree with the suggestion to subdue the false colour on the UV side.
Use B&W or substantially reduce the saturation in the red range.
Then it will be much easier to get the distance from the subject correct
if details are not obscured by the colour.

A small umbrella or some kind of shade over the monitor will help.
Or even a cloth cover over your head and the monitor like in the olden days. La!

Wow! Those e-ribbons off the Raspberry Pi-Cam boards are *huge* !!

Any particular reason why you went with the Nvidia Jetson? I'm just curious.

Also what is the peak of the UV-pass filter? I can't judge the color here because it isn't raw.
I'm guessing between 350-365 nm?

I'm using the NVIDIA Jetson because it has connectors for two cameras and lots of sample applications of using two at the same time. But new products are coming out all the time and will probably switch soon.

Peak of the UV-pass filter? I'm using the MaxMax 330C
https://maxmax.com/s...r-x-2-2mm-thick

What I forgot to mention is that my setup runs on a USB battery pack. No outlet.

Edited by ori333, 06 April 2021 - 22:40.


#15 Stefano

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Posted 06 April 2021 - 23:45

Judging from the graph, the MaxMax 330C filter peaks at 325-330 nm, and the "330" in the name indicates a 330 nm peak. It is a U-340/UG11/ZWB1-type glass with coatings.

#16 Stefano

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Posted 06 April 2021 - 23:51

Is the UV camera monochrome? The ranunculus ficaria doesn't appear reddish (red becomes yellow when white balanced). That would explain the colors. Given the deep peak of the filter and the quartz lens, I would expect the un-white balanced image to appear reddish.

#17 ori333

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Posted 07 April 2021 - 00:51

View PostStefano, on 06 April 2021 - 23:51, said:

Is the UV camera monochrome? The ranunculus ficaria doesn't appear reddish (red becomes yellow when white balanced). That would explain the colors. Given the deep peak of the filter and the quartz lens, I would expect the un-white balanced image to appear reddish.

Yes, the UV camera is monochrome. Specifically, it's an RGB camera with the Bayer filter manually removed. The software doesn't know that yet. ;)

#18 Stefano

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Posted 07 April 2021 - 00:58

View Postori333, on 07 April 2021 - 00:51, said:

Yes, the UV camera is monochrome. Specifically, it's an RGB camera with the Bayer filter manually removed. The software doesn't know that yet. ;)
This explains the color. Since the camera is monochrome you can just convert the image to B&W as David suggested. There's no color information, only brightness.

#19 Andrea B.

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Posted 07 April 2021 - 17:23

The software doesn't know that yet.
Ah, now I understand.

Valentin, the botanical gardens you mention are all very good for flowers and blooming trees and shrubs. In April plants are just beginning to bloom in New Jersey - narcissus, tulips, dandelions, ranunculus ficaria, primroses and anemones. Soon there will be cherry tree and magnolia blossoms. The typical bulls-eye flowers in New Jersey such as rudbeckia and sunflowers are summer bloomers, so those will not be available until June. For Duke Farm, you might need to get permission to photograph in certain areas, but given that you are a Rutgers graduate student, I do not think that would be at all difficult. Duke Farm also should offer some interesting scenes to photograph with their different themed gardens.

I suggest looking for a big bunch of sunflowers at a grocery store or florist shop. Whole Foods and Trader Joes usually have them. So do the other big groceries.

On the forum, you might want to look for Jonathan's (JMC) topic about making some standards. I was thinking that you could create some test posters using those pigments in order to have some UV-dark and UV-bright areas against which to test. I will look for the link and put it here: https://www.ultravio...black-30-paint/
Within the linked topic is a link to further info on JMC's website.

I would also consider that you think about using a UV-pass filter which has a higher peak such as 350 nm (BaaderU) or a 360 nm stack. This is because when shooting outdoors you will have shorter exposures given there is much more 360 nm in sunlight than 330 nm. Of course, your experiment might require the 330 nm peak, but I didn't see anything about a peak requirement?

Lookin' good, keep up the good work!!
Andrea G. Blum
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