Theory of operation
This multi touch display screen design is based on the description in Jeff Han's paper,
Han, J. Y. 2005. Low-Cost Multi-Touch Sensing through Frustrated Total Internal Reflection.
In Proceedings of the 18th Annual ACM Symposium on User Interface Software and Technology
The figure below comes from his web site.
An acrylic panel is edge lit with infrared leds. When your finger comes in contact with the acrylic, it scatters infrared light out the back where it is visible via infrared camera. As long as nothing is touching the acrylic, very little of the light escapes, instead just reflecting around inside. Image processing takes care of detecting tips of fingers and relaying their location to application software. Since the camera "reads" the whole display in parallel, it is easy to detect multiple fingertips at once, even those belonging to multiple users. All this sensing goes on in the infrared spectrum, leaving us free to utilize the visible spectrum to display interactive software.
Han, J. Y. 2005. Low-Cost Multi-Touch Sensing through Frustrated Total Internal Reflection.
In Proceedings of the 18th Annual ACM Symposium on User Interface Software and Technology
The figure below comes from his web site.
An acrylic panel is edge lit with infrared leds. When your finger comes in contact with the acrylic, it scatters infrared light out the back where it is visible via infrared camera. As long as nothing is touching the acrylic, very little of the light escapes, instead just reflecting around inside. Image processing takes care of detecting tips of fingers and relaying their location to application software. Since the camera "reads" the whole display in parallel, it is easy to detect multiple fingertips at once, even those belonging to multiple users. All this sensing goes on in the infrared spectrum, leaving us free to utilize the visible spectrum to display interactive software.
No comments:
Post a Comment