Course on Advanced Projector Geometry topics, Monday 3:45pm

Siggraph 2004 paper PDF Copy | Communications of the ACM September05 PDF Copy

Link to Video

SIGGRAPH 2003 Paper, iLamps: Geometrically Aware and Self-Configuring Projectors [Link]

Projector mailing list [Link]

Mitsubishi Projectors [Link]

Interacting with RFID via Location tracking and Augmented Reality. The manager locates products that are about to expire and get a visual red/green feedback. The manager leaves virtual annotation (to be stored in online database). The employee later retrieves those annotations (big red circles indicate, e.g., those boxes should be thrown away) from a completely different viewpoint.

RFID Location tracking with milimeter level accuracy. The projector beams a temporally unique code for each pixel which is decoded by the photosensor on the tag. The tags can be battery-less because they detect light but do NOT transmit any light. Presence of light is binary 1 and absence is binary 0 in the temporal optical code. The tags respond via RF and transmit the (x,y) coordinate of the pixel that illuminated them. The projector when it receives those (x,y) coordinate from the RF reader, turns on a circle at that (x,y) location. This gives a visual feedback. (In this picture, e.g., red indicate boxes with products about to expire and green indicates otherwise.)

Detecting change from a different viewpoint

A library scenario: Finding which books are on the shelf within the RF range is easy with a traditional (handheld) RF reader. But how can one find out which books are out of the alphabetically sorted order ? With passive photosensing RFID attached to each book we can find the exact location of each book. So, one can verify if there is a mismatch between the list of books sorted by title versus list of books sorted by position coordinates. The mismatch can also be indicated by projecting the arrows back on the shelf indicating the correct position. (Green arrows.) We can also find out if any book is placed upside down. We attach two tags, one at the top and one at the bottom. Books for which the location of the two tags is reversed is marked as upside down. This is indicated visually with red arrows.

Grouping objects

Texture adaptation and placement on moving objects

Prototype tags and projector

Applications in Surveillance, Libraries and Factory Robotics

(Left) Detecting an obstruction (such as person on the tracks near a platform, a disabled vehicle at a railroad intersection, or suspicious material on the tracks). Identifying an obstruction with a camera-based system is difficult, owing to the necessary complex image analysis under unknown lighting conditions. RFIG tags can be sprinkled along the tracks and illuminated with a fixed or steered beam of temporally modulated light (not necessarily a projector). Tags respond with the status of the reception of the modulated light. Lack of reception indicates an obstruction; a notice can then be sent to a central monitoring facility where a railroad traffic controller observes the scene, perhaps using a pan-tilt-zoom surveillance camera. (Middle) Books in a library. RF-tagged books make it easy to generate a list of titles within the RF range. However, incomplete location information makes it difficult to determine which books are out of alphabetically sorted order. In addition, inadequate information concerning book orientation makes it difficult to detect whether books are placed upside down. With RFIG and a handheld projector, the librarian can identify book title, as well as the book’s physical location and orientation. Based on a mismatch in title sort with respect to the location sort, the system provides instant visual feedback and instructions (shown here as red arrows for original positions). (Right) Laser-guided robot. Guiding a robot to pick a certain object in a pile of objects on a moving conveyor belt, the projector locates the RFIG-tagged object, illuminating it with an easily identifiable temporal pattern. A camera attached to the robot arm locks onto this pattern, enabling the robot to home in on the object.

Image stabilization to compensate for handheld motion

Center projector pixel is the mouse pointer while rest of image is stabilized

Scenes cumbersome to inspect can be 'copied' along with data stored on tags, then examined in offices by 'pasting' images after removing geometric and photometric distortions

SIGGRAPH 2003 Paper, iLamps: Geometrically Aware and Self-Configuring Projectors [Link]

Projector mailing list [Link]

Mitsubishi Electric Projectors [Link]

Media Coverage [Link] [Link] [Link] [Link]

High resolution versions of images above [Link]