Drawing with circles... and its relation to image processing

Подписаться 3,8 тыс.

Просмотров 2 тыс.

50% 1

To try everything Brilliant has to offer-free-for a full 30 days, visit brilliant.org/DeepSkyDetail/
You’ll also get 20% off an annual premium subscription.
Ever wonder why people talk about "frequencies" and photographs/astrophotography images? Here's an intuitive explanation for what frequencies are! Image processing doesn't have to be difficult if you know the right terms!
Some great videos on Epicycles (i.e., the "orbits" in this video)
‪@3blue1brown‬ • But what is a Fourier ...
‪@Mathologer‬ • Epicycles, complex Fou...
‪@GoldPlatedGoof‬ • Fourier Analysis For T...
Become a buymeacoffee member to help choose which products I review: www.buymeacoffee.com/deepskyd...
Affiliate Links:
Skywatcher HEQ5 Mount amzn.to/3NVrVQi
Skywatcher 80mm F7.5 Doublet amzn.to/47mbfZi
ZWO EFW mini filter wheel amzn.to/48OxhoN
Optolong LRGB Filter Set (1.25") amzn.to/47r23Tw
Orion 0.8x Reducer amzn.to/47s64a4
USB RJ45 Cable for Controlling Mount amzn.to/4aPlIzu
Raspberry Pi to control mount amzn.to/48mTBWH
R Pi case with touch screen amzn.to/3HvdNKl
ZWO Autofocuser amzn.to/3Skg0hX
ZWO 294MM Pro Camera: bit.ly/3tZmjOo
HEQ5 Mount: bit.ly/3O7VQVz (mine is Orion Sirius, which is equivalent)
ZWO Filter Wheel: bit.ly/3Soo5lw
Optolong Filters (LRGB, SII, Ha, OIII): bit.ly/3SlEPtJ (the Ha and OIII narrowband filters are better than what I have)
Skywatcher Evostar 80mm: bit.ly/4bfVjev (equivalent lens)
USB RJ45 Cable: bit.ly/48FRj50 (connects mount to laptop directly; mine is a different brand, but this should do)
ZWO Autofocuser: bit.ly/425XUDB
0.8x Reducer: bit.ly/3tQlbg7 (mine is Orion, but this should be equivalent)
Join this channel to get access to perks:
/ @deepskydetail
This video was sponsored by Brilliant
00:00 Introduction
00:58 An Unexpected Visitor
02:08 Orbits and Their Shapes
04:00 The First Example
04:43 Brilliant Sponsorship
06:15 Getting to Square 1
07:00 Comparing Example 1 to Square 1
08:08 Fourier Transformations and Sine Waves
09:40 Functions and Astrophotography Images
10:36 Frequencies are Important!
11:40 The Galaxy Drawing
12:10 What a Fourier Transformation Looks Like
13:00 Destroying Low and High Frequency Information

Наука

Опубликовано:

28 июл 2024

Ссылка:

Скачать:

Готовим ссылку...

Добавить в:

Мой плейлист

Посмотреть позже

Комментарии : 25

@whyf16uy 3 месяца назад

Who needs Brilliant when we have Deep Sky Detail. 😁

@deepskydetail 3 месяца назад

Lol! Thanks, but I might get cocky if you say that . Also, Brilliant can be good for practicing what you learn :)

@BrentMantooth 3 месяца назад

Was the audio speed variation intentional throughout? It is amazing how much more efficient Fourier filtering is compared to kernel real space filtering.

@deepskydetail 3 месяца назад

I think it's a combination of me talking faster plus editing out some parts that make the audio speed seem different. It is pretty amazing that Fourier transformations speed up filtering!

@davidandersen208 3 месяца назад

I didn't learn that when i learned about Fourier at university. Mindblowing to see it used for images. Keep up the good work, I'm becoming a bigger fan each new vid ❤

@deepskydetail 3 месяца назад

Thank you! It is amazing what what Fourier transforms can do. I first found out about the orbits thing from a Mathologer video and my mind was blown. It was too cool not to use when introducing deconvolution.

@astrophoto16 3 месяца назад

It’s really excellent work! I'm a fan! I'm waiting for the sequel with the associated deconvolution! I found an article which talks about lucky fourier, a hybrid technique to lucky imaging which would allow more image to be kept to improve the SNR. Is this your final idea?

@deepskydetail 3 месяца назад

Thank you!! I haven't actually heard of lucky fourier. I'll have to check it out :) I've been thinking a lot about this for my new deconvolution tool. And possibly a new noise reduction tool too...

@AstroAF 3 месяца назад

Whew Dr Detail, I’m experiencing 🤯 I might need a brilliant subscription to wrap my head around this!! Cool video Mark, I’m digging your spaceship!!

@deepskydetail 3 месяца назад

Thanks, Doug! It's a complicated topic, and I'm not sure I explained it as well as I could have. But I like my spaceship too! It makes it easier to breathe in space :)

@AstroAF 3 месяца назад

@@deepskydetail 😂 You2 apparently does not have that requirement. I always wondered if stick beings required oxygen…

@deepskydetail 3 месяца назад

@@AstroAF Yeah, apparently, they can breathe anywhere lol!

@xe1zlgg 2 месяца назад

When you talk about circles... you mean wavelets?... I ophthalmologist and have no Idea what you mean with circles. Excellent videos

@xe1zlgg 2 месяца назад

All About high and low frequency understood... thank you.

@deepskydetail 2 месяца назад

you're welcome :) And thank you! Glad you got it! The circles helped me wrap my head around the Fourier transform when I first heard about "high" and "low" frequencies in images. It's not perfect of course (there are no pictures of circles in Fourier space). But I thought it'd be interesting!

@JoeBob79569 3 месяца назад

Damn, I went through a physics degree, but I never fully grasped the usefulness of Fourier transforms until now! It reminds me of how we transmit radio signals, since they are basically high frequencies piggybacking on low frequencies signal, so I assume you _could_ use a Fourier transform to decode a radio signal, but you obviously don't _have_ to..

@deepskydetail 3 месяца назад

Yeah! It's so crazy how Fourier pops up seemingly everywhere. I was just watching a video by Fermilab where they talk about Fourier transforms and the Heisenberg Uncertainty Principle.

@carvrodrigo 3 месяца назад

duuuude that analogy was brilliant!!! You have such good way to mix math and astro, congratz, add more code to it too (as Software engineer in computer vision myself I love to dill into this hahaha)

@deepskydetail 3 месяца назад

Thanks!! Maybe I'll start a new series where I just go over the code. Or maybe it should be a new YT channel, because the YT algorithm can get confused when a channel's topics are too diverse.

@carvrodrigo 3 месяца назад

@@deepskydetail I understand, my suggestion was just to maybe pseudo code, this can be very helpful to engineers like me understand pretty fast the behind the scenes. You create a lot of smart applications and code, it is in the core of the channel 😁 keep the great work man and get yourself an Instagram to talk with the new digital friends hahaha

@deepskydetail 3 месяца назад

That's a good idea :)

@stay_at_home_astronaut 3 месяца назад

The analogies were too highly abstracted for me to understand.

@deepskydetail 3 месяца назад

It's a hard concept, and I didn't explain it very well. I guess maybe it would be better to not think of the circles as analogies. Rather, they are actual representations of the Fourier transformation itself. Maybe this will help: The circles are the Fourier transform applied to a complex wave. Instead of going in a straight line, like at 8:29, the wave travels in a loop. The circles are then the individual sine/cosine waves that make up the looped wave. Think of the function in 8:29 as wrapping around itself. What's nice, is that you can make it look like any outline that you want, from a square to an outline of a galaxy or whatever. Fourier transforms of real images though are just more complicated, and you can't visualize them like the examples. But the same ideas apply: high frequencies = noise and detail. Low frequencies = general structure.