Friday, August 6, 2010

OOH SHINY


I have yet to give up entirely on ShinyTouch, my experiment into creating a touch screen input system which requires virtually no setup. For people who haven’t read my posts from last year, it works because magically things look shinier when you look at it from an angle. And so if you mount a camera at an angle (It doesn’t need to be as extreme as the screenshot above), you end up seeing a reflection on the surface of the screen (this could be aided by a transparent layer of acrylic or by having a glossy display, but as you can see, mine are matte, but they still work). The other pretty obvious idea of ShinyTouch, is that on a reflective surface, especially observed from a non-direct angle, you can see that the distance from the reflection (I guess my eighth grade science teacher would say the “virtual image”) to the apparent finger, or “real image” is twice the distance from either to the surface of the display. In other words, the reflection gets closer to you when you get closer to the mirror. A webcam usually gives a two-dimensional bitmap of data (and one non-spatial dimension of time). This gives (after a perspective transform) the X and Y positions of the finger. But an important aspect of a touchscreen and what this technology is also capable of, a “zero-touch screen”, is a Z axis: the distance of the finger and the screen. A touchscreen has a binary Z-axis: touch or no touch. Since you can measure the distance between the apparent real finger and it’s reflection, you can get the Z-axis. That’s how ShinyTouch works.