
Two Way Mirror Improves Video Conferencing - nsaje
https://hackaday.com/2020/05/29/two-way-mirror-improves-video-conferencing/
======
athenot
This is a cool idea, I often wondered about this.

These days I'm on a 5k monitor and when having a more direct conversation in a
meeting, I make a point to place my Webex video window at the top and center
of my screen. (I never run it maximized, only 1/4 of height & width, so 1/16
of my screen realestate.)

I tested this setup with PhotoBooth and compared when I look at my own face
vs. the actual camera. The difference is minor.

Bonus, it signals to whom I'm speaking whether I'm looking at some other
window or at them. This is useful for empathetic listening.

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spankalee
With so much multi-image computational photography and video processing these
days, I've been wondering whether we could have a multiple camera system (with
cameras on the top, bottom, left, and right of the screen) and a processor
that can simulate a camera in the center of the screen - or even dynamically
moved to the eyes of the caller.

I know there's a bunch of research on viewpoint interpolation, but how close
might we be to a dedicated processor to be able do this in a laptop, or at
least specialized VC monitor?

~~~
rckoepke
Apparently all current attempts resulted in very, very uncanny valleys. This
thread mentions some current attempts (searching hn.algolia.com for 'gaze
correction' will return additional threads).

[https://news.ycombinator.com/item?id=24151123https://news.yc...](https://news.ycombinator.com/item?id=24151123https://news.ycombinator.com/item?id=24151123)

~~~
dehrmann
Even with multi-camera setups?

~~~
TaylorAlexander
Seems possible. If the user is actually looking at the center of the screen
then we only need to shift the view, not digitally move their eyes. That seems
very doable with some GPU code.

~~~
Const-me
> That seems very doable with some GPU code.

This seems about as hard as digitally moving eyes.

I think the main source of artifacts is going to be lighting and reflections.
Specular color or reflections are only possible to see when light, surface
position and normal, and observer are arranged in a specific way. If you have
2 or more cameras positioned elsewhere, there's no way to find out what color
is visible to another camera in the center.

Modern AI can try to guess, but fundamentally there's no that info anywhere in
the video. It can assume the object surface is made of small count of uniform
materials, and extrapolate materials across picture and across frames, but
this gonna fail too often for biologicals subjects like people.

~~~
TaylorAlexander
Moving eyes means making decisions about human behavior, which is hard. Any
weirdness will be very detectable. Just doing a 3D reconstruction with
multiple cameras is more established field.

~~~
Const-me
> Just doing a 3D reconstruction with multiple cameras is more established
> field

Yes, but that alone is not enough. You can indeed reconstruct 3D after
spending enough resources, but that won’t help you finding out which color the
camera is going to see, because of these reflection issues. Human eyeballs are
very reflective. Even if you approximate them with spheres and distort the
reflections accordingly, next subject will wear eyeglasses, the reflecting
shape of these is arbitrary, you have no chance of doing that accurately
enough.

The worst-case example is a person wearing eyeglasses which are completely
flat on the outside. No matter how many cameras are around the screen, none of
them will capture what would reflect in the eyeglasses for a missing camera at
the center of the screen.

I think people will eventually solve that, not with AI postprocessing, with
hardware. You can place a camera behind center of the screen, and split time
between display and camera. For example, you light the display for 10ms, and
for the next 6.66ms you turn off the display and instead read data from the
camera. This will get you 60Hz of both display and camera.

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dorkwood
It's funny how videos such as this, which are optimized for engagement over
learning, explain things in a backwards fashion. Instead of explaining how the
thing works, and then showing you how to make the parts to build one yourself.
They show you how to make the parts, and only explain what it is you're
building at the very end.

~~~
xmprt
He never said the video was supposed to be about learning. The entire channel
seems to be based around technology crafts. It's not my cup of tea but that
doesn't mean no one else shouldn't enjoy it.

~~~
dorkwood
Oh, I didn't say no one would find it enjoyable. It's quite the opposite,
actually: videos optimized for engagement tend to be more enjoyable for most
people. You don't get to 2.4 million subscribers by making videos that no one
likes to watch, after all.

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nkristoffersen
Essentially a teleprompter. Been looking at doing something with my external
camera for all of the video calls these days.

[https://www.bhphotovideo.com/c/buy/Teleprompters/ci/2122/N/4...](https://www.bhphotovideo.com/c/buy/Teleprompters/ci/2122/N/4028759394)

~~~
xyzzy_plugh
> Checkout is unavailable while we observe Shabbat. Please come back when
> checkout reopens at 9:00 pm ET Sat Aug 22

Huh, I guess this never crossed my mind, but makes sense. TIL.

~~~
stan_rogers
It has ever been thus. Back in the day, when film still ruled the world and
B&H's main claims to fame were grey market and East European cameras, they
were widely known as Kosher Kamera in the enthusiast world. Back then, you
needed to be careful about the day and time you posted a mail order as well.
(The prohibition extends beyond working to _causing_ work. While they didn't
consider mail in flight to be their responsibility, any order postmarked
between sundown Friday and sundown Saturday was, in a sense, their fault.)

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op03
Thats how Errol Morris does his magic -
[https://www.youtube.com/watch?v=BEsoSR2npes](https://www.youtube.com/watch?v=BEsoSR2npes)

(The Interrotron)

~~~
tyingq
A diagram of how it works:
[https://a.fastcompany.net/upload/interrotron1.jpg](https://a.fastcompany.net/upload/interrotron1.jpg)

------
chenster
Facetime will be doing that in iOS 14
[https://appleinsider.com/articles/20/06/22/facetime-eye-
cont...](https://appleinsider.com/articles/20/06/22/facetime-eye-contact-
correction-feature-to-launch-with-ios-14)

------
simonhamp
I always recall an Apple patent[1] from years ago that posited interspersing
the camera pixels with the display pixels. I wonder where they got with
that...

[1]:
[https://patents.google.com/patent/US7535468B2/en](https://patents.google.com/patent/US7535468B2/en)

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kuon
Well, I really hate eye contact and never look people in the eyes, so this
wouldn't be something interesting for me. I wonder if I am alone or if this is
common.

~~~
lnanek2
That's actually an advantage in the remote work world, because you can stare
at the camera and people will think you are looking them in the eyes. They'll
trust you more thinking you are, and if you can't read their face anyway,
there's no loss to you due to looking at the camera instead of their face.

~~~
randycupertino
I've found I trust people less who are staring at the camera, because they are
prioritizing building psuedo-webcam empathy over actually looking at and
following along with/understanding our shared screen.

I dunno. But at some point you can tell who's faking it. Sort of like someone
who read How to Win Friends and Influence People and follows it to the letter-
they use your name too often shoehorned into conversations and ask about your
dog a little too early and enthusiastically with feigned interest.

Perhaps this is a cynical viewpoint brought on negatively from too many zoom
webcam meetings!

~~~
jesselawson
Randy I think that's a great take. I can tell you put a lot into it, Randy.
That's great. Books are great resource for learning--I agree, Randy!

~~~
randycupertino
I had a coworker who (pretty obviously, mind you) kept a One Note tracker of
EVERYONE at the company's dogs, cats, and children. Wouldn't have a meeting
with her for another 15 months? She'll ask you how Doja and Steve the
chinchilla are doing. When she could get them, she'd also store photos of
them. She considered herself a "networking genius."

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allenu
Errol Morris famously uses a two-way mirror contraption for his documentaries
so that when he interviews his subjects, they are looking directly into the
camera as if they were talking to you. It definitely gives a more intimate
feel when the subjects are talking.

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wiradikusuma
At the end of the video, he tried it with his friend who's _not_ using the
apparatus. Yet, her eyes seem to be looking at him too. What do you think?

~~~
thomasahle
Me too. I felt like she was looking more into my eyes than he was.

Maybe I've just gotten too used to video calls...

~~~
chrisan
That was actually my initial reaction too.

I've found if people are just a lil bit further away from their camera they
appear to be looking at me anyways.

A conference call should be like a conference table wrt how big their head
should appear, once you reach that distance I really can't tell you aren't
looking directly into the camera

------
Terretta
The GlideGear iPad teleprompter is under $200 and saves a lot of time if
you’re pressed for time:

[https://smile.amazon.com/gp/product/B019AJOLEM/](https://smile.amazon.com/gp/product/B019AJOLEM/)

The setup is to use an iPad hosting Sidecar wireless display from your Mac.
Use Moom or similar screen management app that detects kicking on the new
display, and pops your meeting video windows onto it at full dimensions (but
not ‘full screen’ mode).

If the other person is both on video and sometimes sharing content, you need
to flip the video horizontally, which isn’t obvious. There are three options:

1\. Check if your display can flip the video.

2\. Use SwitchResX if your graphics card can do it for that particular
monitor:

[https://www.madrau.com/](https://www.madrau.com/)

If it can, great. If it cannot, then ...

3\. Use the Flip Mac Window utility from here, so you’ll see it the right way
around in the mirror:

[https://www.freetelepromptersoftware.com/mac/](https://www.freetelepromptersoftware.com/mac/)

How this works is it screen captures the original window, and plays it back
flipped over top of the window. That means actual buttons / icons _are not
moved_ , only the rendering of the window is flipped. If you need to navigate
the window, unflip it first.

Note that 12.9” iPads _only_ fit in this GlideGear if you re-shape the mirror
brace, but the mirror _is_ large enough for a 12.9” iPad and it looks
fantastic.

I like coupling this with Logitech Brio (best) or Logitech Streamcam (good).

I‘ve used it extensively with WebEx, Zoom, and Teams.

~~~
Tepix
The neat thing about the DIY solution is that you can move around the camera
so that it is placed over the eyes of the other person.

~~~
Terretta
The webcam can be repositioned behind this mirror as well, but generally
people are reasonably centered.

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dTal
Couldn't you lie the screen completely flat and build it the other way
(reflecting the screen and passing through the camera), avoiding the keyboard
problem?

~~~
CrazyStat
That's how traditional teleprompters work: screen below reflecting off the
half-silvered mirror, camera behind.

Many laptop screens don't open completely flat, so that may not work for this
particular concept.

~~~
throwaway316943
The tutorial is already suggesting harvesting a web cam from a laptop, why not
just extract the screen instead? Lots of info and equipment out there for
repurposing laptop screens.

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kstenerud
> but that means you aren’t looking at the camera and, thus, you aren’t making
> eye contact.

But that's what I love most about video conferencing: You don't have to make
eye contact. The only thing better is voice-only with a shared presentation
space.

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gunnarmorling
Working on a similar set-up myself; got a proof-of-concept running using Duplo
bricks [1], the quality of good teleprompter glass is really impressive.

[1]
[https://twitter.com/gunnarmorling/status/1296043605459705856](https://twitter.com/gunnarmorling/status/1296043605459705856)

~~~
Tepix
You can‘t adjust the camera position quickly during a video call, can you?

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ghaff
Quite cool although:

1.) I find if you put the video conference window top and center of a monitor
--preferably a larger one--it works pretty well so long as you make at effort
to keep your eyes towards the top of the screen. This is especially important
(and takes some discipline) if you're presenting from slides.

2.) The general recommendation, which is my experience as well, is that the
webcam should be up at eye level or maybe a bit above. So if you are using a
laptop, it should be up on some books or other type of stand.

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hazeii
If you have a multi-monitor setup, make a slight gap between two of them and
put the camera behind the gap. Then position the video window so the camera is
central to it.

~~~
c-st
Wouldn't that split the face of the person you are talking to in half?

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hyperbovine
This is basically just a teleprompter in reverse. If you’re okay with spending
slightly more $$, just buy one of those instead:

[https://www.amazon.com/Glide-Gear-TMP100-Adjustable-
Teleprom...](https://www.amazon.com/Glide-Gear-TMP100-Adjustable-
Teleprompter/dp/B019AJOLEM/ref=sr_1_3?dchild=1&keywords=teleprompter&qid=1598187692&sr=8-3)

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Zenst
This trick has been used for a whole in VC studio's for decades and I first
encountered this in the 90's. Being able to get eye-level contact with the
camera when people will want to look at the screen - this just solves that.
Just not cheap.

Though lighting was always key and with the two-way mirror set-up, you will
want a few more lumens to compensate for loss of that mirror in front of the
camera.

~~~
Someone1234
"VC Studio?"

~~~
Zenst
Video conferencing room dedicated for such tasks.

------
sn41
Very cool. This is somewhat similar to the mechanism of flipping a rearview
mirror in order to dim lights from behind at night.

------
l0b0
Related video[1] about teleprompters, including some insight into the nitty
gritty.

[1]
[https://www.youtube.com/watch?v=YeRu4xYH_W0](https://www.youtube.com/watch?v=YeRu4xYH_W0)

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manigandham
Side note: that channel (DIY Perks) has tons amazing projects. I'll never
actually do any of them but the project breakdowns and assembly are fun to
watch.

------
throwaway316943
What we really need is a decent AR or VR headset for remote conferencing.

~~~
gowld
If you are wearing a headset, what would your conversation partners see?

~~~
throwaway316943
An avatar. You really don’t need much else to get a superior experience to a
video call. Being able to turn towards the person who is speaking, see the
posture they are holding and have 3D audio is far better than 2d faces in
little boxes. It’s also lighter on bandwidth so you don’t wind up talking to
laggy robots.

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nooyurrsdey
cool idea. but a picture is worth a thousand words. would've loved a simple
image of the setup instead of reading 5 paragraphs describing it, found it
really hard to parse in my head.

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dirtnugget
Well, sadly it makes the laptop basically unusable without external mouse and
keyboard.

~~~
gowld
It's for video-calls, which don't need mouse and keyboard.

~~~
dirtnugget
Well, when I do video calls at work (and thats more than 90% of my video
calls) I frequently find myself needing to look up something or edit tickets
in Jira. Or showing code. So I would argue, some people do.

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nottorp
The best way to improve video conferencing is to stop doing video
conferencing.

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mathieuh
I haven't actually had a single video-conference since lockdown started.
Plenty of audio-conferences with 50+ people for show and tells, and if two
people turn their cameras on it's suprising.

Personally I'm very happy with this. Means you can tune out and keep working
on stuff that matters to you when the call starts going off-track or out of
your area.

------
rootsudo
I make sure to video conference right in front a mirror and I find it's no
issue for me, but for this video:

1\. The video itself uses the cliche "weird" baitclick.

2\. Honey sponsership.

On Hackaday.

That's just sad, hackaday used to not be like that.

Guess really it's the times.

