Progressive Transmission of Digital Images

Vision: To allow high-performance image browsing over low-performance networks.

Benefits: This project will allow students, scientists, and other Web users to browse and download large images over slow networks. Digital image librarians will benefit from reduced storage and network demands.

Accomplishments: We have finished the Progressive Image Transmission system prototype and it is in use by astronomers to conduct remote observations with large ground-based telescopes.

This page shows the dramatic improvement in network speed using our technique of Progressive Image Transmission. We chose an astronomical image of stars and galaxies, which has 800 rows and 800 columns. This is large compared to images currently being sent over the Web.

The picture on the left shows the fraction of an image received after 60 seconds using a 2400 baud modem and the traditional sequential method of transmission. Only a tiny sliver of the image has been received, at the bottom. The picture on the right is the same image, also after 60 seconds using a 2400 baud modem, but this time using our method of Progressive Image Transmission.

Dr. Jeffrey W. Percival e-mail:
Space Astronomy Laboratory phone: 608-262-8686
University of Wisconsin FAX: 608-263-0361
Madison, WI 53706 USA