Jeff Han
Department of Computer Science
Courant Institute of Mathematical Sciences
New York University
email: jhan at

Note! This site is no longer being maintained!
I have not been affiliated with NYU since 2006, when I founded Perceptive Pixel

Research Interests:
I am a consulting research scientist for NYU's Department of Computer Science, currently working with Yann Lecun on various autonomous robot navigation projects, while also finding time to direct some of my own research.

Over the years, I've also worked with several other professors at Courant, including Ken Perlin on great projects like the Kaleidoscope, with Denis Zorin on mesh simulation, and with Chris Bregler on motion capture.

My research interests have historically been real-time computer graphics and real-time computer vision, but I've taken on a more recent focus on human-computer interfaces and machine learning.

Coming soon:
Autonomous robot navigation, FPGA implementations, more sensing...

Some recent projects with NYU colleagues:
Multi-Touch Interaction Research
Bi-manual, multi-point, and multi-user input on graphical interaction surfaces
(in progress)
Multi-Touch Sensing through Frustrated Total Internal Reflection
Detecting multiple finger touches on a rear-projection surface
Paper at ACM UIST 2005

A simple, inexpensive, and scalable technique for high-resolution multi-touch sensing

LED Touch Display
Multi-touch sensing on LED matrix displays
(in progress)

LEDs are photodiodes too!
(more details to come soon...)

Media Mirror
An interactive video installation, in which 200 channels of live cable television are continuously rearranged in real-time to form a mosaic representation of the person that stands in front of it.
(in progress)
MoCap Sensor Fusion
Augmenting motion capture, with the capture of other physiometric data, such as breathing
(in progress)
High-Speed, Low-Cost Eyetracking
Utilizing a new generation of CMOS imaging sensors that feature on-board signal processing functionality, we are experimenting with creating a 1000fps non-invasive eye-tracker for under $100.
(in progress)
The HeliOS project
Advisor to a great group of engineering students on their Senior Design project- an autonomous navigation system for R/C helicopters.
Advisor, Spring 2005
A true open-air volumetric display
(in progress)

Ultra-fast 3D particle position tracking system utilizing lateral-effect photodiodes

A minimalist social network tracking pin
one thousand pins distributed at Ars Electronica 2004
(with Brad Paley, Peter Kennard)

System design, hardware, firmware architecture
Capturing surface reflectance data using a kaleidoscope
full paper at SIGGraph 2003

Measuring Bidirectional Texture Reflectance with a Kaleidoscope
Han, J. Y. and Perlin, K. Computer Graphics, Volume 22, Issue 3 (Proceedings of SIGGRAPH 2003)

A clever arrangement of mirrors allows for fast measurement of 6D bidirectional texture functions (BTFs), in-situ, with no moving parts. Realtime dataset rendering on the GPU. Extended to the acquisition of fully 8D reflectance fields. Coming soon: a freely available BTF and BSSRDF sample library
Realtime Optical Flow on the GPU
A pyramidal, iterative implementation of the Lucas-Kanade-Tomasi feature tracker on commodity graphics hardware, running densely, per-pixel with sub-pixel precision, at typical performance gains of 5x-10x over CPU implementations

Utilization of dedicated mipmap hardware, early Z-cull for iterative loop termination, and other fragment shader assembly optimization techniques
The Animated Napkin Sketch
presented at Microsoft Faculty Summit 2003

A TabletPC brainstorming tool that features the use of stroke timing information to promote the creative process. Exports to Flash movies (.swf files) for easy dissemination

PowerToy coming soon!
ACCESS- A Public Art Installation
Robust real-world motion tracking of human targets
exhibited at Eyebeam, SIGGraph 2003, Ars Electronica 2003

Optical flow analysis allows a movable spotlight to follow around unsuspecting persons in a public space

Tracking data is also brought out to a Flash MX interface, for multi-channel video streaming, and network user participation

Self-Collision Detection and Response for a Fracturing Thin-Shell Simulator
poster at SCA 2004

System specifically handles dynamic insertion of new edges into the mesh, as when fracturing
OpenGL Proxy DLL for Multi-View Displays
One of the primary research directions in our lab is novel display devices, including foveal and autostereoscopic displays.

So it made sense for us to create a versatile OpenGL proxy wrapper, which enables unmodified OpenGL applications to generate stereo/multiple views with the proper swizzling, for a variety of devices.

The Foveal Desktop
A hi-resolution display effected through a coaxial arrangement of projectors

Some trickery to get the Windows desktop to render into both resolutions
A proxy DLL for OpenGL applications (see above)

In a previous life...

I used to work on a little something called CU-SeeMe

Copyright © 2003, 2004, 2005, 2006, Jefferson Y. Han
last updated Feb-2006