
Monroe or Einstein?  Instant eyesight check. - btilly
http://lifehacker.com/5823098/monroe-or-einstein-check-if-you-need-glasses-at-your-computer
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jnhnum1
For the curious, I believe this works by doing a Fourier decomposition of both
images. Then the composite image is produced by taking the low-frequency
components from Monroe, and high-frequency components from Einstein. This way
the "details" of the image look like Einstein, but the "overall" image looks
more like Monroe.

~~~
jwn
Not to take this off-topic, but I never understood how an image can be
converted into a Fourier series. It always made sense for waves, but images?

~~~
dcosson
Imagine the waveform of a sound wave - there is an amplitude for each point in
time, which you can easily take a FT of. This waveform could also be, say, a
vibrating guitar string at a fixed moment in time, in which case the units are
amplitude vs. distance, but it is still just a function that you can take a FT
transform of (now the "frequency" domain is the inverse of distance rather
than the inverse of time, but it still works). An image is just a function of
amplitude vs. distance, though there are 2 distance variables since an image
is 2-dimensional, but the idea is the same, and the Fourier Transform is still
defined for functions of 2 or more variables. In a color jpeg, I believe this
is done individually for red, blue, and green, and the point at which you cut
off the infinite series of Fourier coefficients determines image quality.

That said, this picture is awesome! I've never seen it done before.

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gxs
Please heed this warning. I didn't get an eye exam til my last semester in
college.

Turns out, I've always needed glasses - and the reason studying was such a
pain was because I was really straining my eyes. I always wondered how some
people could study all day while I'd max out at 3-4 hours.

I got glasses and my last semester grades were quite good - please get your
vision checked!

~~~
tobtoh
I experienced the same thing ... here's another test from personal experience
... if you look at a leafy tree and it looks like a brown stick with a green
ball on top ... your vision is bad!

I know that sounds ridiculously obvious - but when your eyesight gets
progressively worse, you simply don't realise how degraded it has become. I
distinctly remember the first time I got glasses, walked outside and was
amazed I could see individual leaves on the tree! It was like I had upgraded
to a HD TV!

~~~
kleim
Same here. I had difficulties not to cry the first time I put my glasses
because I found everything was so wonderful!

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Cushman
Glasses on: Einstein. Glasses off: Monroe.

So that's pretty cool. Of course, by the time I can see Marilyn, even the
headline under the photograph is already blurred past recognition. If I squint
so I can read the text, I can make out that it's actually Albert.

So, more of a cool face hack than a real utility.

Edit from below, for people who aren't nearsighted: Close one eye, put your
thumb on the screen just under the image, and focus on your thumb as you draw
it back towards your face. You can see Albert change into (blurry) Marilyn
before your very eye!

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pixdamix
Here's the paper detailing the process:
[http://cvcl.mit.edu/hybrid/OlivaTorralb_Hybrid_Siggraph06.pd...](http://cvcl.mit.edu/hybrid/OlivaTorralb_Hybrid_Siggraph06.pdf)

[1] <http://en.wikipedia.org/wiki/Hybrid_image>

~~~
datr
I remember reading this a few years back. The effect is actually really easy
to recreate in photoshop from two photos. Our college magazine at the time was
running an issue on the incoming student union committee so I knocked up a
"double-image" for each position and wrote a short piece about the paper.
People loved it.

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ssp
Simply downscaling the image will also turn Einstein into Monroe, which
demonstrates that it's non-trivial to even define what correct downscaling
means.

~~~
socksy
You may be interested in this article that was on hacker news a while ago:
<http://www.4p8.com/eric.brasseur/gamma.html>

And the hacker news discussion: <http://news.ycombinator.com/item?id=1523991>

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Shenglong
I can't see Monroe no matter how hard I squint, or how far back I am.
Although, maybe this room isn't big enough... How far back are we supposed to
go? Or did I get trolled?

~~~
Cushman
Try closing one eye, putting your thumb on the screen just under the image,
and focusing on your thumb as you draw it back towards your face. You can see
Albert change into Marilyn before your very eye!

(That's what it's like for nearsighted people all the time. With glasses on, I
can roughly simulate the blurriness of no glasses by focusing on my thumb
about six inches from my face, with the image about two feet away.)

~~~
Shenglong
Works like a charm!

~~~
dfranke
Not for me :-(. I see Einstein no matter what I do. I've never in my life been
able to resolve stereograms, either.

~~~
ern
There is a sidebar on the right hand side of the page that lists the top
stories, and it has a smaller version of the image. I was able to see Marilyn
in that one without much effort.

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sgift
The tragedy of being really near-sighted: I see Einstein with glasses on and
nothing/only blurry colors (whole page) with glasses off.

~~~
simonsarris
Well that makes you fortunate in one regard because you absolutely know you
are near-sighted!

This test would have helped those like me. I'm near-sighted but not too bad. I
can't really read text well from afar and didn't have glasses until 8th grade
though I apparently needed them for some time. I always say at the front of
the class because I just assumed text on the blackboard was not visible from
the back for everyone.

Figuring out that I needed glasses opened my eyes, so to speak.

~~~
5hoom
My story is similar. I never had problems with the concepts taught in
maths/physics/etc classes but always seemed to get the questions on the
blackboard wrong as I just couldn't see the writing properly. I got an eye
exam around the 8th grade & was diagnosed as near sighted but before then I
just thought the world was blurry and that everyone saw things like that :)

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Luyt
With my left eye, I can't focus on objects closer than 12 inch.

With my right eye, I can't focus on objects further than 26 inch.

I have glasses to correct this, but without glasses I can comfortably use a
computer at a 'sweet spot' distance of 18 inch ;-)

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benpbenp
Doesn't Monroe with no first name mean James Monroe? Because of this I was
_really_ trying hard to see the president, all the more confused because I
_am_ nearsighted.

~~~
j_baker
I think they mean Marilyn Monroe.

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peng
Doesn't work for me. I see Einstein both with glasses and without (Monroe only
becomes apparent if I'm 3 feet away sans glasses). However, text becomes
blurry with glasses off.

~~~
klipt
Same for me. I guess that just means I don't need glasses _that_ badly. They
still help prevent eyestrain though.

~~~
keeptrying
If you dont need glasses then I would not use them because they will only make
you dependent on them.

There is a study which shows that spending more time outdoors and looking at
far away objects will help alleviate eye problems.

<http://redsports.sg/2009/01/07/sunlight-myopia/>

If you search around in google I think yoiu'll find a copy of the paper.
Really worth a read.

~~~
klipt
Well no, I can see Einstein but letters are still blurry without glasses.
Reading that way is a great way to get eyestrain and headaches.

Also your study is about children - nothing says that will reverse myopia in
adults.

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jrockway
Another test: if you can read the text, you can see your computer screen.

(I sort of see Monroe out of my right eye with my glasses off. But the text is
so far gone at that point that I would have no hope of reading why I'm looking
at a picture of Monroe with a mustache.)

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teamonkey
A much larger version of this (and its explanation) is on display in the MIT
museum.

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darklajid
I'm near sighted, have glasses - and the image looks the same with and
without.

~~~
reemrevnivek
Marilyn or Einstein?

~~~
darklajid
Einstein

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Hominem
looked over the top of my glasses and it changed instantly to Monroe. I would
prefer they changed the text from short-sighted to near-sighted though.

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glasseson
I really must put on my glasses before kissing.

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SonicSoul
ooh its like one of those 3D posters. if you stare at it long enough and make
your eyes blurry Marilyn emerges.

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rat
With my glasses it looks like Einstein.

