Finally a spy camera killer

[Al]

Check out this
http://www.cc.gatech.edu/~summetj/cre/

It's about time!

Al

 

[Jim Thompson]

Check out this
http://www.cc.gatech.edu/~summetj/cre/

It's about time!

Al

Why not just a 1000W-sec strobe that fires whenever it senses another
strobe?

...Jim Thompson

 

[Paul Hovnanian P.E.]

Check out this
http://www.cc.gatech.edu/~summetj/cre/

It's about time!

I think the movie studios were looking at something like this to prevent
camcorders from operating in movie theaters. Simple countermeasure: an
IR filter.

 

[Si Ballenger]

Check out this
http://www.cc.gatech.edu/~summetj/cre/

It's about time!

Al

I got my IR remote and checked with my webcam. Anything remotely
shiny (like the clear plastic cover on a name tag would probably
set it off considering their big array of IR LEDs, not to mention
fun with a hidden IR led. When it flashes in your face, you act
startled, trip and fall, then your personal injury lawyer sues
the sh*t out of them for such a horrible prank!

 

[Ian Stirling]

I think the movie studios were looking at something like this to prevent
camcorders from operating in movie theaters. Simple countermeasure: an
IR filter.

It can still be done by visible light.
However, an appropriate arrangement of polarisers can defeat this, light
can get into the lens, but only of one polarisation, and when it tries
to get back out it's blocked.
There are other ways.

An interesting closely related effect.
If you defocus your eye so that the camera flash and the camera lens are
blurred into one, then the 'red eye' turns into very bright demon-like eyes.
The reason is that 'red eye' is the light diffusing through the retina
to the point next to the image of the flash on the retina, to the image
of the lens.
If you defocus the eye, then you can get the much brighter direct image,
not just the sideways light-leak through the retina.

 

[Robert Latest]

On Tue, 20 Sep 2005 00:28:06 GMT,

I got my IR remote and checked with my webcam. Anything remotely
shiny (like the clear plastic cover on a name tag would probably
set it off considering their big array of IR LEDs, not to mention
fun with a hidden IR led. When it flashes in your face, you act
startled, trip and fall, then your personal injury lawyer sues
the sh*t out of them for such a horrible prank!

I think the way it works is that the LCD projector aims directly at the
camera lens (the retroreflector), not the entire scene. But the human
eye is a bit retroreflecting, too, so you might get occasional flashes
into your eye.

I think the idea has greater potential as a system to freak out cats.

robert

 

[Ian Stirling]

On Tue, 20 Sep 2005 00:28:06 GMT,


I think the way it works is that the LCD projector aims directly at the
camera lens (the retroreflector), not the entire scene. But the human
eye is a bit retroreflecting, too, so you might get occasional flashes
into your eye.

IR.
It's presumably picking a wavelength where the eye is not so transparent.
Hang on, CCD, silicon, so under 900nm or so.
I thought the eye was fairly transparent there.

 

[René]

Why not just a 1000W-sec strobe that fires whenever it senses another
strobe?

...Jim Thompson

The movie shows that it cannot work right: the ir camera view shows
the ir reflection of the phone-cam brighter as the pick up element
itself.

Wonder what happens if you walk by wearing glasses, looking at the top
secret gadget. Will make the product real popular....

 

[Ian Stirling]

The movie shows that it cannot work right: the ir camera view shows
the ir reflection of the phone-cam brighter as the pick up element
itself.

Wonder what happens if you walk by wearing glasses, looking at the top
secret gadget. Will make the product real popular....

When you shine a light at a camera, the light goes into the camera, and
forms an image.
However, the camera also projects the light that's reflected from the
imager out through the lens, towards the light source.
This can be millions of times brighter than a mirror would be.

 

[Ken Taylor]

When you shine a light at a camera, the light goes into the camera, and
forms an image.
However, the camera also projects the light that's reflected from the
imager out through the lens, towards the light source.
This can be millions of times brighter than a mirror would be.

Care to explain how?

Ken

 

[Ian Stirling]

Care to explain how?

Err, I mean millions of times brighter than an ordinary surface.

It's about as bright as a mirror pointed just right.
Imagine a beam of light striking the camera - it forms a point of light
on the imaging surface (modulo resolution et al).
This point of light is maybe half absorbed by the imaging surface (film,
retina, chip, bitumen, ...) and a large portion of hte rest reflected back
out the lens in a beam back to the source, due to reciprocity.
Reciprocity basically just means that a photon can take the return path
just as easily as the forward path.
The illuminated point and the spot work like a laser pointer to make a
beam back at the source.

 

[Robert Latest]

On 20 Sep 2005 10:27:13 GMT,

When you shine a light at a camera, the light goes into the camera, and
forms an image.
However, the camera also projects the light that's reflected from the
imager out through the lens, towards the light source.
This can be millions of times brighter than a mirror would be.

It can, but it ain't. Just look at the AVI movie demonstrating the
technique: The reflection off the convex plastic surface of the cell
phone is brigther than that from the actual lens. It's easily seen in
the "Camera detection" sequence of the movie.

What I don't get is that the geniuses who implemented the system must
have been aware of this fact because it really jumps out at you, yet
they put it right into their marketing flick. Their target audience must
be really stupid.

robert

 

[Al]

I got my IR remote and checked with my webcam. Anything remotely
shiny (like the clear plastic cover on a name tag would probably
set it off considering their big array of IR LEDs, not to mention
fun with a hidden IR led. When it flashes in your face, you act
startled, trip and fall, then your personal injury lawyer sues
the sh*t out of them for such a horrible prank!

Hey, it's a proof of concept paper. Stay tuned for commercially produced
devices.

The movie stars who want privacy will love this. I can see a stooge
accompanying a star carrying something like this just above eye level.
Or else built into a home security system.

Al

 

[Mark]

any ordinary IR source can blind a camera.

Most CCD cameras are sensitve to IR.

this is hype


Mark

 

[Ian Stirling]

Check out this
http://www.cc.gatech.edu/~summetj/cre/

It's about time!

Al

Why not just a 1000W-sec strobe that fires whenever it senses another
strobe?

The movie shows that it cannot work right: the ir camera view shows
the ir reflection of the phone-cam brighter as the pick up element
itself.

Wonder what happens if you walk by wearing glasses, looking at the top
secret gadget. Will make the product real popular....

When you shine a light at a camera, the light goes into the camera,
and
forms an image.
However, the camera also projects the light that's reflected from the
imager out through the lens, towards the light source.
This can be millions of times brighter than a mirror would be.

 

[Ken Taylor]

Check out this
http://www.cc.gatech.edu/~summetj/cre/

It's about time!

Al

Why not just a 1000W-sec strobe that fires whenever it senses another
strobe?

The movie shows that it cannot work right: the ir camera view shows
the ir reflection of the phone-cam brighter as the pick up element
itself.

Wonder what happens if you walk by wearing glasses, looking at the top
secret gadget. Will make the product real popular....

When you shine a light at a camera, the light goes into the camera, and
forms an image.
However, the camera also projects the light that's reflected from the
imager out through the lens, towards the light source.
This can be millions of times brighter than a mirror would be.

Care to explain how?

Ken

 

[Ian Stirling]

Check out this
http://www.cc.gatech.edu/~summetj/cre/

It's about time!

Al

Why not just a 1000W-sec strobe that fires whenever it senses another
strobe?

The movie shows that it cannot work right: the ir camera view shows
the ir reflection of the phone-cam brighter as the pick up element
itself.

Wonder what happens if you walk by wearing glasses, looking at the top
secret gadget. Will make the product real popular....

When you shine a light at a camera, the light goes into the camera, and
forms an image.
However, the camera also projects the light that's reflected from the
imager out through the lens, towards the light source.
This can be millions of times brighter than a mirror would be.

Care to explain how?

Err, I mean millions of times brighter than an ordinary surface.

It's about as bright as a mirror pointed just right.
Imagine a beam of light striking the camera - it forms a point of
light
on the imaging surface (modulo resolution et al).
This point of light is maybe half absorbed by the imaging surface
(film,
retina, chip, bitumen, ...) and a large portion of hte rest reflected
back
out the lens in a beam back to the source, due to reciprocity.
Reciprocity basically just means that a photon can take the return
path
just as easily as the forward path.
The illuminated point and the spot work like a laser pointer to make a
beam back at the source.

 

[Robert Latest]

On 20 Sep 2005 10:27:13 GMT,

When you shine a light at a camera, the light goes into the camera, and
forms an image.
However, the camera also projects the light that's reflected from the
imager out through the lens, towards the light source.
This can be millions of times brighter than a mirror would be.

It can, but it ain't. Just look at the AVI movie demonstrating the
technique: The reflection off the convex plastic surface of the cell
phone is brigther than that from the actual lens. It's easily seen in
the "Camera detection" sequence of the movie.

What I don't get is that the geniuses who implemented the system must
have been aware of this fact because it really jumps out at you, yet
they put it right into their marketing flick. Their target audience
must
be really stupid.

robert

 

[Al]

On Mon, 19 Sep 2005 19:52:15 GMT, Al <[email protected] wrote

Check out this news

http://www.cc.gatech.edu/~summetj/cre

It's about time

A

I got my IR remote and checked with my webcam. Anything remotel
shiny (like the clear plastic cover on a name tag would probabl
set it off considering their big array of IR LEDs, not to mentio
fun with a hidden IR led. When it flashes in your face, you ac
startled, trip and fall, then your personal injury lawyer sue
the sh*t out of them for such a horrible prank

Hey, it's a proof of concept paper. Stay tuned for commerciall
produced
devices.

The movie stars who want privacy will love this. I can see a stooge
accompanying a star carrying something like this just above eye level

Or else built into a home security system

A

 

[Mark]

any ordinary IR source can blind a camera

Most CCD cameras are sensitve to IR

this is hyp


Mar