Optical Camouflage

To All:

http://www.youtube.com/watch?v=JKPVQal851U

    Is it trick? Or a trick? :)
    And for metalworking content - How do you machine a brick you can't
see, eh?
--
BottleBob
http://home.earthlink.net/~bottlbob
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Very interesting. Sniper Wear!!
Cool!
Gunner
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
BottleBob wrote:

It's hilarious to read the comments. Idiots speculating and fighting over what it really is, when the answer is right there in the description.... See sig. :D
--
We have broken from reality--a psychotic Nation. Ignorance with a pretense of
knowledge replacing wisdom. -- Ron Paul
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The idiot should take his own advice instead of attempting to run for congress once again.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
13:30:28 -0800, BottleBob, snipped-for-privacy@earthlink.net wrote:

One click away, Katy Couric believes:
http://www.youtube.com/watch?v=Y4zwzlnExVU&NR

Then again, IME, journalists are some of the most clueless people on earth. Just last night, ABC's David Wright(?) was telling us how it'll take 35 days to manually offload 4 tons of supplies from a ship in the port of Haiti. I have to guess he meant 4 thousand tons, but that's the problem with people on teevee today... you're always having to guess what they really meant.
For context: A moving crew of two can offload a moving van with 9 tons of household goods/furniture in ~2/3 of a day.
--
☯☯


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
BottleBob wrote:

Very simple video trick, called "chroma keying". You wouldn't even notice it on broadcast TV, they use it all the time to paint "studio sets" over plain furniture, TV weather maps, etc. All you need is an object with a color that doesn't appear anywhere else in the set, and the video switcher can be set to substitute video from a different source when it sees that color. In this case, they used an effects generator to memorize the background before the guy stepped in front of the camera. When the camera sees the key color, it switches to the memorized background.
The first started doing this chroma key stuff about 1965 or so, so it is REALLY old TV technology.
Jon
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The Very first thing in the description is: "Please read this before you comment"
It is NOT chroma keying.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Half-nutz wrote:

Well, unless I see a demo in person, with my naked eyes (well, OK, I need glasses to see more than 6", but...) I am NOT going to believe this at all! This gadget needs to grab photons from behind the guy's head and send them on toward your eyes without altering their path at all. I find it REALLY hard to believe such a device can exist at all, and that it fits is a 4" sphere that the guy waves around.
It defies what I know of physics that he is doing this, so I require a **LOT** more proof than a you-tube video!
If it is not strictly a chroma-key job, then it is effectively the same thing, video mask cutting of the image.
Jon
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yikes..
The background is a projection. If he wears a reflective coat, then it reflects the projected image, just like the projection screen behind him does. And thus the shiny coat appears to be the background, and thus invisible. Even if he is front of a real background, there is a projector where the view is from, projecting the background. Again, his shiny/reflective coat is painted with the background.
Not a chroma key job. And not even quite the same thing. You could be standing there, and observe the effect. No Way you look at a green screen chroma key studio and see the finished result with the naked eye.
How does that defy physics?
Pretty cool eh?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Half-nutz wrote:

OK, so the ball is maybe painted with the glass bead stuff they put on highway signs, so it reflects really well back toward the light source? That's pretty simple, and has a similar effect when viewed from a single vantage point. A true "cloaking device" would show whatever was behind the ball, so if you moved your head, the view would change, like looking through a window. This trick would not work that way, you'd just get the same projected view.
Jon
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jon Elson wrote:

He's using a projector.
--
We have broken from reality--a psychotic Nation. Ignorance with a pretense of
knowledge replacing wisdom. -- Ron Paul
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
sittingduck wrote:

We had a system (front projection) that did this when I was a studio photographer in the late 1970's.
It consists of a large retroreflective screen behind the 'actor', and a camera and projector in front of the 'actor'. (If you're not sure what 'retroreflective' is, think of the highway signs that seem to glow brightly in the dark when illuminated by your headlights - it reflects most of the incident light directly back along the axis of incidence. A typical brand name is 'Scotchlite')
The camera and projector are arranged to be on exactly the same optical centerline, usually by having a 'straight shot' for the camera and the projected image is added in through a half-silvered mirror at right angles to the camera lens axis.
The image from the projector is reflected back to the camera from the retroreflective screen, and the screen is very high gain and directional so it reflects mostly back along the incident axis.
The actor is carefully lit so the incident light does not swamp out the reflective screen image.
Anything in the scene that is supposed to look transparent is simply made of retroreflective material - so the actor's coat, the ball and the block are retroreflective and appear transparent because they are reflecting the incident background image back to the camera.
See also <http://en.wikipedia.org/wiki/Front_projection_effect
Carla
"Any sufficiently advanced technology is indistinguishable from magic." Arthur C. Clarke
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Carla Fong wrote:

Excellent summation. Excellent quote too!
--
We have broken from reality--a psychotic Nation. Ignorance with a pretense of
knowledge replacing wisdom. -- Ron Paul
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You hire a blind machinist.
Wes -- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.