FTIR touchscreen progress
Well, I got the acrylite sheet cut and mostly polished today. My leds didn't arrive :(~~~ but they should be here monday. I also ordered some UV glue which should also be here this week. I can't wait until I have this thing assembled. While I'm waiting I guess I should start on the software end. I want to write my own blob detection and tracking code.
I also recieved another web cam I ordered, advertised as an 'infrared webcam'. Basically it just seems to have no IR filter and it comes with some IR LED's. This is fine since I jacked up the focus on my creative webcam when I did the IR hack.
BTW, I do plan on putting up some pics and instructions if I can get this thing working (prolly some software too). I plan on supporting OSC (open sound control) and I will use OpenCV for capturing the video.
I also recieved another web cam I ordered, advertised as an 'infrared webcam'. Basically it just seems to have no IR filter and it comes with some IR LED's. This is fine since I jacked up the focus on my creative webcam when I did the IR hack.
BTW, I do plan on putting up some pics and instructions if I can get this thing working (prolly some software too). I plan on supporting OSC (open sound control) and I will use OpenCV for capturing the video.
5 Comments:
I have come across another problem. you cannot stick anything onto the sheet of acrylic to capture the image from the projector in thease other videos there almost appears to be some sort of fabric streached over the screen.
The projector screen is placed on the back side of the touch screen - it's very important that there is an air gap (1/4 inch maybe?) in between the acrylic and the projector screen otherwise you will break the internal reflection (the same as when your finger touches the screen).
sweet , on another note with the edgest of the sheet , i hav heard of a few guys geting places to laser cut them , gives a nice perfect edge.
Ray, in the original paper published by Jeff Han, he first writes that the rear projection screen be (as David suggests) separated from the acrylic by a small air gap. The problem with this is the visual disparity between the touch surface and the projected image 1/4"+ away.
Since the acrylic gets marked up pretty quickly, he goes on to suggest using a "compliant overlay" (specifically rear projection Rosco Gray #02105) placed directly on the front surface. This serves as both the projection screen (now with zero disparity) and an acrylic-protecting film.
Regarding the edge polishing, It might be a good idea to only polish the points where the LEDs attach. I did the entire perimeter and see a lot of light escaping the wave-guide. Wouldn't it make more sense to rough up most of the edge so that light stays inside? Ideally, you'd have a mirrored edge except where the IR is introduced ...
I'm guessing the projection screen material is pretty expensive. I've been wondering if there was another material that might substitute - like a translucent grey vinly shower curtain maybe??
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