Wild possums

I left my webcam recording overnight at where I knew possums were entering and leaving my house. This is what we found.

Pictures of IR webcam

The IR filter, stuck on with electrical PVC tape.

The CMOS

The filter on the lens. It has the same reddish tint but doesn't seem to block IR. I wonder what the tint does?

More infrared pictures

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I found that Australian notes also have IR markings. This is the front of the $50 note. The person's picture disappears. The "05" in mirror image on the top left is actually on the other side of the note; the note is slightly transparent.

The back of the note

Close up

Interpolation

To test whether the "6M pixels" make a difference, I took 2 pictures, 1 at 3648 × 2736, 1 at 1280 × 1024, both in bmp format. The big one was a whopping 29.9 MB while the other was 3.9 MB. I've cropped both here.

6M pixel one:

Small one:

They look the same to me.

More infrared pictures

Great news, I got the IR allowing filter and the camera works perfectly. This camera is extremely easy to take IR pictures with, since it has no IR blocking filter.

1. Cut filter to cover lens
2. Stick over lens, making sure no gaps (use black tape)
3. Find a strong IR light source (incandescent bulbs produce about as much IR as visible light)
4. Take pictures!

Also, it works with XP without installing anything! Can only take 640×480 pictures though.

All pictures: left, visible. Right, IR.

See how the pattern on the lowest cloth disappears in IR.

The brightness of the light (100W) looks the same under visible and IR, barring exposure changes.

You can see the lights on the camera.

I can finally take a picture of the whole note at once! Ok I gotta stop taking pictures of money.

It's interesting how ink is transparent to IR.

Lastly, this picture was taken in IR. The colour tint comes from some visible light getting through the filter. Fluorescent bulbs produce much less IR than incandescent.

More infrared pictures

More of the note. Apparently only 1 stripe has the image.

Veins really DO show up well in IR! At first I couldn't get them to show up, then I found out you have to hold your veins quite far away, almost out of range of the LEDs. This is the back of my hand. It's not like that under visible light.

Infrared webcam

I bought an infrared webcam from eBay to try and take IR photos.

Approx AUD$7 (including delivery) from here. Or just search for "infrared webcam" on eBay. Make sure the LEDs are IR, not visible light! All the cheaper ones I found (including the one I bought) control the LEDs automatically, you can't force them to turn on. Those that let you control them are visible light LEDs.

Trying to do things from here http://www.hoagieshouse.com/IR/ and some interesting things with plastics.

Notes on the camera:

1. 8M pixel is interpolated, of course. I don't think there's any difference between 6, 8 and 10M pixels (if it's the same hardware).
2. The lens screws right out. You can see the CMOS. Will upload pictures next time. The back of the lens has a filter with a red tint just like in the website. I hope it's not an IR filter.
3. Software is basic. Some image effects and frames. I would like time lapse and security camera functions.
4. Camera doesn't work in OS X Photo Booth when I just plug it in (it appears in the camera list though). Might need drivers.
5. IR has different focus from visible light!

2 pictures taken of a remote control (handy source of IR light): left, with Apple's iSight. Right, with this webcam. Background shows exposure was roughly equal in both pictures. The IR light is brighter in the right image, so hopefully the camera doesn't have an IR filter.

Here are 2 pictures I took of a Chinese banknote with the webcam. Left, IR. Right, visible. Pictures are of the same region. They seem to use a special ink that doesn't reflect IR light. The camera's instructions look the same under IR light. Australian money also looks the same.

More pictures of the Chinese banknote. This time, half the image is visible under IR light.

Looking for a filter that blocks visible light and allows IR light!