Outline

• Introduction
• Principle
• Experiment
• Analysis
• Demonstration
• More information 

Introduction

• TAI-CHI: Tangible-Acoustic Interfaces for Computer Human Interaction
• Current CHI hardware
• Tangible (Touchable)
• Majority
• Example: Mice, Keyboards, Touch Screen
• Intangible (Non-touchable)
• Limitation of Current Tangible Devices
• Tangible Devices restrict the mobility of users
• Users must be in certain locations during interaction
• and certain devices
• Touch-screen is normally
• Small size of computer screen
• Expensive

Application examples of tai-chi

• Interactive windows in shops or public services
• Low cost PC and video game interfaces
• Large interactive screens for academic presentation
• Novel musical instruments
• Novel interactive artistic interfaces, such as interactive painting

Solutions

• Time-delay of arrival (TDOA)
• Using a number of sensors
• Computing the differences in the arrival time of acoustic signals
• Location pattern matching (LPM)
• One or more sensors
• Localised by matching the recorded signal patterns

Principle

The LPM method is following a few steps below:

1. Initilisation stage
1. Vibration generated by finger tapping
2. Signal conditioning
3. A/D conversion
4. Acquisition of template signals
2. Comparison
1. Compare the new signal with the recorded templates
2. Correlation coefficient is used to determine the level of similarity

Experiment

• Conversion of a glass panel into an acoustic sensitive surface.

Compare difference sampling rates

The same signal pattern with three different sampling rates. 

 

 

Analysis 1

a. Correlation coefficients distribution when sampling rate is 1kHz.

b. Standard deviations of correlation coefficients with sampling rates from 1 KHz to 31 KHz.

Compare differente resolutions

The same signal pattern is digitilised with different resolutions: 16bit, 12bit and 8bit. 

Analysis 2

a. Correlation coefficient distribution when digitisation resolution = 8 bits

b. Standard deviation of correlation coefficients with digitisation resolution levels between 8 and 16 bits.

Compare different sample lengths

Three recorded acoustic signal patterns with different signal lengths.

Analysis 3

a. Correlation coefficient distribution when sample length = 5 ms

b. Standard deviation of correlation coefficients with sample lengths from 5 ms to 60 ms.

Demonstration

Please click on the links below to see the video demonstration.

 

Demonstration

Please click on the links below to see the video demonstration.