IndexPen: Two-Finger Text Input with Millimeter-Wave Radar.

Wei, Haowen*, Ziheng Li*, Alexander D. Galvan, Zhuoran Su, Xiao Zhang, Kaveh Pahlavan, and Erin T. Solovey.

Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 6, no. 2 (2022): 1-39.

IndexPen Cyber Image
IndexPen Teaser

Duration: August 2019 – September 2022
Role: Project Lead, Lead Software Engineer, First Author
Advisor: Dr. Erin Solovey & Dr. Kaveh Pahlavan

IndexPen Demo

I was writing "Hello World"

Overview

IndexPen is a touch-free text input system that uses millimeter-wave radar to detect two-finger in-air micro-gestures. This system, developed as part of my undergraduate project at WPI, can recognize 30 distinct gestures (A-Z, Space, Backspace, Enter) plus a noise differentiation class. Achieving 95.89% accuracy in a 10-day study and 88.3% F-1 score for first-time users through transfer learning, IndexPen demonstrates the potential for intuitive, hands-free text input in various environments.

My Contributions

  • Leadership: Led the project from concept to implementation, overseeing data collection, model development, and signal processing.
  • Deep Learning: Designed and implemented a CNN + LSTM model for radar-based gesture recognition.
  • User Study: Conducted studies with 30 participants to validate system accuracy and usability.

Key Features

  • Touch-Free Input: Uses radar to detect in-air gestures, providing a hands-free method of text input.
  • Natural Gesture Recognition: Recognizes 30 gestures, allowing users to write the English alphabet naturally without physical contact.
  • High Accuracy: Achieved 95.89% accuracy across 31 classes and 86.2% sentence accuracy in user studies.

Novelty

  • Introduced a novel approach to gesture-based Human-Computer Interaction, enabling intuitive text input in sterile or hands-free scenarios through radar and deep learning.

Awards & Achievements

  • 2022 Best Undergraduate Major Qualifying Project at Worcester Polytechnic Institute, 3rd Place..

Supplementary Video:

IndexPen

Download Paper | Dataset | Video