2011

 
 

Project Overview

 

The project was to develop a conferencing system that could ease teleconferencing between a group of users and a remote user. What was developed was an array of microphones that can track users by triangulating the source of their voices and then point a camera in their direction. The topics covered include the selection of project components, design of project circuits and software, and recommendations for future developments. The project was completed successfully with a working prototype that can determine the direction of a voice and point a camera in the direction calculated. The final implementation of the device used 2 microphones and would be best suited for use at the end of a conference table as it can only track 180 degrees. The design for a three microphone array was completed, however, it was not implemented due to time constraints. Of the recommended changes in the future, the top priorities would include changing the digitally operated camera for a pulse wave modulation servo operated camera mount and to use a microcontroller with fewer features to reduce the cost of the project.

 

As with any new project that is to be carried out, sufficient research needs to be done in order to assess the novelty and necessity of the product being designed. The main goal of this project is the following:
·Use audio as a means to track and differentiate between speakers
·Autonomously control a camera or camera platform to center on speaker
·Ease of use
·Low cost
·Cross-platform

 

Much of camera tracking today involves facial recognition and following the pattern of the face that has been recognized. The Logitech QuickCam® Orbit AF is an excellent example of this; it has a motorized tracking optics system which keeps the user centered in the middle of the picture. Unfortunately this system is relatively expensive. In addition it is not able to effectively track multiple speakers in a conferencing scenario, and the drivers for the camera are not available for Mac OS X. Ultimately, the QuickCam® and similar products cannot not satisfy the requirements of this project.

 

Further research exposed some hardware that is able to sense the direction of incoming sound such as the Acoustic Magic Voice Tracker I Array Microphone®. This system utilizes an array of 8 directional microphones spaced 5cm apart. The array calculates the direction of the sound source and displays the direction on a row of LEDs on the face of the device. While this system is fairly accurate in determining the direction of the sound, it only provides one analog stereo output signal and no means of transmitting the detected direction to another device such as computer or microcontroller. Consequently users are still left to manually controlling the direction in which their camera is facing, and thus failing to adhere to the specifications of the project.

 

Here is a short video demonstration of the Sound Source Triangulation in action within a MATLAB GUI.




(Above) Complete block diagram of the enhanced teleconferencing system as per the final report.


(Below) Preamp Circuit for the Mics.