infrared camera and lens for live tracking?

Nov 3, 2008 at 6:41pm

infrared camera and lens for live tracking?

i’m just about to buy this camera

http://www.1394store.com/eshop/product.asp?dept_id=55&pf_id=2063

and i want to get a lens that filters out visible light and only lets in
infrared light, so that i can do better tracking. I also plan on making a
little circuit board with self-powered ir LED lights to put on a dancer’s
body, to add more tracking refinement.

does anyone know where i can get an ir lens? so far, i can only find lenses
that filter OUT ir light…

how have other people done this? Also, I looked through the jitter archives
but didnt see anyone mentioning planting ir LEDs on the subject to track -
has anyone taken this approach? Or is there a better way that is just as
discreet?

cheers, robbie

#40641
Nov 3, 2008 at 10:03pm

Hi Robbie,
It’s not so much that you need an IR lens, but rather a camera that can capture into the IR and a lens or filter that takes out visible light. In my experience most black & white cameras extend to the near IR. Color cameras not so much. Many of them have a physical filter or painted film that filters out the IR. Some of these color cameras can be easily modified to rid of the filters, others not so much. Search on-line for some DIY hacks if color is a must. Since you are capturing IR anyway, best bet is b&w. Then you need a filter. There are lots of DIY options discussed on line (like developed, unexposed slide film), but there are also professional options such as Tiffen’s #87 filter for camera lenses. I have one of these taped to a b&w security camera at the moment with great results.

WRT IR led’s: I’ve done this before for a sort of minority-report type finger tracking with great success. Issues you are going to run into are distance (the ole 1/r^2 law), and line of site issues when the dancer is moving around (i.e. you’ll need coverage all the way around arms, legs, head, etc. if you don’t want to lose that limb in your tracking).

Last suggestion would be to use Jean-Marc Pelletier’s fabulous cv.jit objects!!

HTH,
David

#143954
Nov 3, 2008 at 10:33pm

while it is correct that b/w cameras offer better spectral sensitivity in
the ir range ,the infrared sensitivity of this particular sensor found in
the color unibrain fire-i model picks at the 630nm range which with the
correct filter, (like david mentions, an exposed photography film) works
great.
see page seven of this
http://unibrain.com/download/pdfs/Fire-i_Board_Cams/ICX098BQ.pdf
buying a color camera offers more flexibilty in setup as sometimes color can
be nice

b/w cameras offer an added bonus of having done with the bayer pattern color
ccd’s have, read about it all and more here
http://unibrain.com/Products/VisionImg/tSpec_Fire_i_BC.htm and wikipedia.

goodluck, infrared +is+ nice

On Tue, Nov 4, 2008 at 12:03 AM, David Beaudry
wrote:

>
> Hi Robbie,
> It’s not so much that you need an IR lens, but rather a camera that can
> capture into the IR and a lens or filter that takes out visible light. In my
> experience most black & white cameras extend to the near IR. Color cameras
> not so much. Many of them have a physical filter or painted film that
> filters out the IR. Some of these color cameras can be easily modified to
> rid of the filters, others not so much. Search on-line for some DIY hacks if
> color is a must. Since you are capturing IR anyway, best bet is b&w. Then
> you need a filter. There are lots of DIY options discussed on line (like
> developed, unexposed slide film), but there are also professional options
> such as Tiffen’s #87 filter for camera lenses. I have one of these taped to
> a b&w security camera at the moment with great results.
>
> WRT IR led’s: I’ve done this before for a sort of minority-report type
> finger tracking with great success. Issues you are going to run into are
> distance (the ole 1/r^2 law), and line of site issues when the dancer is
> moving around (i.e. you’ll need coverage all the way around arms, legs,
> head, etc. if you don’t want to lose that limb in your tracking).
>
> Last suggestion would be to use Jean-Marc Pelletier’s fabulous cv.jit
> objects!!
>
> HTH,
> David
>
>
>
>

#143955
Nov 5, 2008 at 5:05pm

to filter out visible light you can use polarizer filter (http://www.youtube.com/watch?v=QgA6L2n476Y), and the gut think is, it doesn’t block the IR light.
You can bay original foto filters or
Inexpensive solution is just to pill it of any old or new Liquid crystal display.
http://www.raphnet.net/divers/projection_clock/polarized_sheet_removal3.jpg
In order to work you need two filters to put infront of the camera like in youtube example.

#143956
Nov 5, 2008 at 5:10pm

I forgot;
this can only work with cameras that have no IR filter.
UNIBRAIN would be gut solution.

#143957

You must be logged in to reply to this topic.