• Coffee Table
  • Day 1
  • Day 2
  • Day 3
  • Day 4
  • Day 5
  • Day 6
  • Day 7
  • Day 8
  • Day 9
  • Day 10
  • Conclusion
• Whiteboard

Day 4

IR Lamp

The IR lamp arrived the day after I ordered all the gear that I decided I wanted in order to proceed. The lamp with its 140 880nm IR LEDs is meant to be incredibly bright, with the original IR filter (cut from the inside of a floppy disc) and camera in place and all the camera settings set to their maximum sensitivity, contrast, white balance etc. I was only just able to make out the reflection from the spotlight. My impatience at this stage led me to grab another floppy disc of a differing brand and cut a new filter from that. I found a marked improvement in the amount of IR light that was visible through this filter. I was able to read input in the centre of the IR lamps 'hotspot' on the table surface at 6 frames a second using the original camera. This allowed me to interact with the table for the first time ever. Even though it was extremely temperamental, hard to calibrate and barely useable it was a good feeling.

Below are some images of the IR lamp and one of the assembled IR kit that that it is to replace, below those is one of it in-place next to the projector behind the original camera still using the original filter. The film you see hanging in front of the IR lamp is a section I cut from the double matt drafting film to help defuse the IR light, decreasing the intensity of any IR hotspot and scattering a little light about the room (you can see the box for the new camera on the floor as these pictures were taken after the majority of gear had arrived).

Below on top on the left is the image seen through the original camera with the IR Blocking filter removed (which does make the image blurry) the yellow box on top is the projector lamp overuse warning. The image on the right is the same setting but with the new 140 LED IR Lamp turned on. The bottom image on the left is with the original filter in place, even at this smaller resolution you can see the noise on the black portion of the image and how small of an impact having the IR lamp on has made to the image compared to being unfiltered. On its right is an image as taken through the improved IR filter cut from the second floppy disc. As you can see it is far better than the original filter however it is far from perfect.

 

Graphics Acceleration

The second item to arrive from my spending spree was the graphics card. I grabbed a second hand GF8900 card threw it in and went and ticked the graphics acceleration option using the old camera/lens and improved filter only to find that with the mode enabled the capture application ignored the amplification settings and they seemed to be locked on full amplification even with it disabled. The result was that the noise coming from the camera was generating a blob (input 'touch') for each little spec of noise. In addition to this the software flip features were being ignored also. This made the purchase of the graphics card seemingly irrelevant, it gained nothing in the short term however the GPU acceleration feature of the input software (Community Core Vision) was marked experimental.

Web Cam Upgrade - Philips SPC900NC

The third item to arrive was the new webcam, the Philips SPC900NC. The camera is famous all over the web in amateur astrology circles often being used in addition with telescopes for photography of the surface of the moon and other photographs; the fame is well earned. As soon as I had the camera working, even on the lower resolutions, I notice a huge improvement in the image quality. Very sharp with no visible noise and at the 640x480 it even achieved its 90 frames per second as advertised. In the input capture software I was able to get 45 frames a second with the settings set for the old camera (the old camera getting at most 7 frames per second). I was unable to test the camera at this stage with the IR for input at the lens that comes with the camera has the IR blocking filter painted on the lens (so I could not remove it) and the replacement lens without filter was on its way. Additionally the new Long-Pass filter that would block visible light and allow only IR light to be seen had not arrived either.

I quickly checked that the lens was easy to remove and insert a new one. The camera housing doesn't need to be opened in order to replace the lens, the ring that is used to adjust the focus of the original lens pops off easily when pried with a small flathead screwdriver. Then using a screwdriver in the hole where the ring spokes go I was able to unscrew the lens.

Visible Light Filter Comparison

When the Long Pass filter arrived I jumped at the opportunity for another filter comparison. I got out the original filter, improved filter and the new Long Pass filter and took these images (as well as those shown above in the IR Lamp section)

As you can see the image was far clearer when using the professional filter. The filter is not properly installed in that image it has only been sat on a small piece of blu-tac on the outside of the camera.