With the help of people in the AI Lab, I filmed a local grocery store five blocks away from the Computer Science Department called Mr. G's located here in scenic Hyde Park in Chicago.

By going down each aisle four times filming in four directions, I captured north, south, east, and west views. This, of course, all happened in the middle of the night (3 A.M. actually) when nobody wants to be in a grocery store (including the people who stock the shelves). Of course, the best laid plans go awry. We thought we could use Jim Firby's robot Chip to take pictures. The process was very slow... four hours later with one aisle filmed we had to leave since the store was opening. Next week we came back with a video camera to film the aisles faster. Unfortunately we couldn't capture many items on film since the aisles were so narrow. The third time we were armed with a wide-angle lens. The fourth time too. Whew.

After filming the store, I got the tape pressed onto a laserdisc. I then wrote a database program that computed the views that you're supposed to see based on the location in the store. Then, it tells a laserdisc player to play an image. The particular laserdisc player is a Pioneer LD-V8000 which has a serial port so our Sparc 20 can control it. Unfortunately, using a CLV-formatted laserdisc on the LD-V8000 means that image accesses can take up to five seconds.

For the web version, Mike Swain suggested that I do prefetching of images, but I ended up doing simple caching. So, if you go to a well-traversed part of the store, accesses will be fast. When the image is accessed the video goes to our vision machine - the "DataCube" - which digitizes the image. At that point the image is transformed to color/greyscale (whichever is preferred) and then shrunk to match the requested size. Finally, the image is converted (compressed) to JPEG or GIF format for faster transfer. JPEG will always be preferred unless your browser can't handle it.

This research is funded in part by the Office of Naval Research grant number N00014-91-J-1185.

Last modified 07 November 1997