Design and Implementation of Smart Multi-Touch Interface Using Special Purpose CORDIC Processor

Abstract

This paper presents a smart and embedded multi-touch system for consumer electronics. The infrared (IR) camera is utilized to capture the coordinate of the IR blob from IR stylus or human finger in an emitted IR field. This system allows the consumer to easily convert large surface, projector screen, or conference table into multi-touch interface. The keystone distortion of IR camera is compensated by using homography. To improve the user experience, the calibration of homography is automatically triggered by accelerometer sensor. The special purpose (SP) processor with the parallel COordinate Rotation Digital Computer (CORDIC) architecture computes the observation-to-track association, and the computation result updates the motion status of each tracked trajectory. These motion data support the multi-touch tracking system to evaluate the sliding window of each tracked trajectory for reducing the tracking error. Additionally, the motion data are reused by the adaptive trajectory estimation (TE) system to smooth the touch trajectory and mitigate the measurement noise. This research presents multiple autonomous functions to provide a user-friendly multi-touch interface for consumer electronics. These include the automatic calibration system, the multi-touch tracking architecture with motion estimation system, and the adaptive TE system.