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greetings and kind regards
perhaps some here have seen YouTube videos of mathematics whereupon presenter writes on apparent glass pane and is seen apparently behind said pane yet the writing is facing the viewer as shown in link below . how the heck does that work ???
https://www.youtube.com/watch?v=GuiIyYbI0HM[^]
thank you kindly
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I'm betting it is a real glass (or plexiglass or something similar), and he really is writing on it, and the footing has been flipped left-to-right.
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Thank you for your kind assistance in this matter. May I please inquire what is a "footing"?
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The individual film frames. I don't know where I've heard the term used in the film industry - maybe my dyslexia has it confused with another term.
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The glass pane is a "drawing" device ... what he "sees" is shown (on) somewhere else ... A "screen" behind / in front of the glass pane (depending on your perspective). Then a transparent screen that projects back to the audience. And his glass is one-way so he doesn't get thrown off. (Or none of the above).
"Before entering on an understanding, I have meditated for a long time, and have foreseen what might happen. It is not genius which reveals to me suddenly, secretly, what I have to say or to do in a circumstance unexpected by other people; it is reflection, it is meditation." - Napoleon I
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Note that the guy appears to be writing with his left hand. He may of course be a 'leftie', but it is more likely that he is writing with his right hand, and the image has been mirrored, to get the mirrored text on the glass back to normal.
Religious freedom is the freedom to say that two plus two make five.
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this is a most interesting and educational topic. Thanx. Who would have thought!
"A little time, a little trouble, your better day"
Badfinger
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Greetings and Kind Regards
There are many YouTube videos re/ "Classical/Lagrangian/Hamiltonian/Advanced Mechanics"
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jmaida wrote: Who would have thought!
Da Vinci, for one. It's been well documented that he learned to write 'backwards' so as not to stain his sleeves with ink, and then you had to use a mirror to read his notes. Something like that anyway.
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Not so much as writing backwards, Da Vinci was a crazy genius.
I was referring to "the writing on glass techniques". Very clever.
Still trying to fully understand the camera play.
"A little time, a little trouble, your better day"
Badfinger
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jmaida wrote: Still trying to fully understand the camera play.
What is difficult to understand?
The guy writes on a transparent surface (glass or plastic - that doesn't matter) with some sort of pen that leaves very solid lines on the glass. Because the camera sees the writing from the back of the glass, it appears mirrored, written from right to left. So the electronic mirror the mirrored image, which is trivial: Just scan the lines in the opposite direction.(*) The text comes out the right way.
Also, the guy is mirrored. But as the camera sees him directly through the glass, he is not mirrored, to the camera. So when the processing mirrors both text and man (by scanning lines backwards), he comes out mirrored: His right hand, which writes the text, looks like a left hand.
If you want to see the scene the way the camera saw it, watch your screen via a mirror, and you will see that the guy is right handed.
(*)
Mirroring is so trivial that my first digital video camera, bought in 1997, did it in the camera. I had an underwater house for it, but there was no way to use the ocular viewfinder from outside the house. The camera had a large foldout LCD viewfinder screen, but you couldn't fold it out inside the house, and it would not be easy to see from outside. But you could flip this screen around and fold it back to the camera body, with the image side pointing out, straight to the left. Then the viewfinder image flipped to mirrored.
Why? The house had a clear window right in front of the screen. On the outside of the house was a mirror that would fold out 45 degrees. When I looked into that mirror from the back end of the camera, I saw the mirror image of the LCD viewfinder inside the underwater house. Since I viewed it via a mirror, the LCD image had to be mirrored to come out the right way to my eyes.
This was done 25+ years ago in an amateur video camera. Doing it with today's electronics is probably even simpler than trivial.
Religious freedom is the freedom to say that two plus two make five.
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Well, it seems to me like it's the same thing, no?
The presenter writes on glass in the "normal" direction, which looks backwards to the camera, and anyone looking at it from the other side - like DaVinci's notes.
Then the video is mirrored, just as you'd use a mirror to read DaVinci's notes. I don't think there's anything special about the camera. You just post-process the recorded video.
You can do the same with VLC, by using Tools / Effects and Filters / Video Effects / Geometry / Transform / Flip horizontally.
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An investigation mystery.
Presenter is Dr. Peter Dourmashkin.
So which hand does he favor? Right hand. Look how he writes on the chalkboard at 3:58 in the following video.
8.01x - Lect 24 - Rolling Motion, Gyroscopes, VERY NON-INTUITIVE - YouTube[^]
So with the video from the OP...starting as 0:32 (and 2:05) seconds in he writes on the screen.
He is using his left hand.
Also if you look at 0:08 he is also gesturing with his left hand.
One might claim that he is just ambidextrous but it seems unlikely that he would gesture like that also.
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Wordle 931 2/6
🟩⬛🟨⬛🟩
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🟩⬜🟨⬜🟩
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In a closed society where everybody's guilty, the only crime is getting caught. In a world of thieves, the only final sin is stupidity. - Hunter S Thompson - RIP
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Wordle 931 6/6
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Just managed.
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Wordle 931 5/6
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“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
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Wordle 931 6/6
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Ok, I have had my coffee, so you can all come out now!
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Wordle 931 5/6*
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1:01.27
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I know some (many?) of you cook, and I know we are a transnational group - might be the wrong term - how about global community. I'm interested in your kitchen. One disease I *had* in my home for decades is the lack of a proper range vent. You know, one of those things that when you turn it on, it vents stuff to OUT of the house. Around the late 70s in the US, house designs went cheap or bat crap stupid - you pick. Instead of venting range gases to the exterior, they "filtered" them and put it right back in the house. This might have been driven by trying to make houses more energy efficient, I honestly don't know.
Years later, I came across Asian co-workers who had HUGE vents (industrial grade) in their kitchens. I am certainly not judging as I love fried rice, but it made me start thinking about this venting issue. My house was built in 1988, and I have the blessing of a "whole house fan." Open a few doors and windows and this will ventilate your house in 10 minutes. I treasure it. Please keep in mind that with the # of children I've raised and am raising (10+ grand kids at the moment, not all are here), 100% efficiency went to hell and a hand basket a long time ago.
A few years ago, I redid my kitchen, and my mandate was - real vent fan. I'm interested - from across the world - are these normal? Also - do you cook on gas or electric? Up until 3 yeara ago, I was always electric. Take my gas range, and I'm going John Simmons on you.
Happy New Year and may you be blessed.
Charlie Gilley
“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759
Has never been more appropriate.
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My experience has been fans that vent to the exterior unless this was impossible or the architect was so stupid as to come up with a floor plan where it could have been done but wasn't.
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may i say i am w/ the wokes on this one . must be electric probably induction (most modern perhaps most efficient certainly easiest to clean) as gas fumes are not meant to be inhaled . by the way who is this John Simmons of which whom you speak .
modified 6-Jan-24 1:46am.
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