The Robotics Institute
RI | Seminar | January 24

Robotics Institute Seminar, January 24
Time and Place | Seminar Abstract | Speaker Biography | Speaker Appointments

The Promise and Perils of Near-Regular Patterns

Dr. Yanxi Liu

Robotics Institute, CMU

Time and Place

1305 Newell-Simon Hall
Refreshments 3:15 pm
Talk 3:30 pm


We are surrounded by near-regular patterns that are (1) man-made: textiles, architectures, walls, pottery, arts, website structures; (2) biological: cells, DNA structure, faces, brains, human and animal bodies, feathers, various types of gaits; and (3) natural: waves, leaves and sand patterns. With the increasing power of computer hardware, lack of computer algorithms to understand and capture near-regular patterns has become more and more obvious. This shortage is preventing autonomous computer systems from readily taking full advantage of regularity when modeling the real world. Recognition of regularity is the first step towards capturing the essential structure of a problem, while at the same time minimizing computational redundancy. One of our research aims under the topic of computational symmetry is to fill this gap.

This talk will start with one of our recent results on near-regular texture synthesis to demonstrate the advantage of explicitly acknowledging the existence of regularity without losing sight of randomness.   The mathematical framework for our work is based on the theory of periodic patterns (crystallographic groups). I shall introduce our computational models for periodic and bilateral pattern perception, and report their applications in 1) texture synthesis, 2) texture replacement, 3) gait analysis, 4) neuroimage analysis and 5) human face identification under expression variation. Though algorithmic treatment of near-regular pattern analysis is promising, I shall also point out several potential perils along the way.

Speaker Biography

Dr. Liu is a faculty member affiliated with both the Robotics Institute (RI) and, more recently, the Center for Automated Learning and Discovery (CALD) of Carnegie Mellon University (CMU). She received her Ph.D. in Computer Science from the University of Massachusetts, where she studied the group theory application in robotics. Her postdoct training was done in INRIA of Grenoble, France. Her research interests including biomedical image analysis and computational symmetry.

Speaker Appointments

For appointments, please contact Yanxi Liu (

The Robotics Institute is part of the School of Computer Science, Carnegie Mellon University.