Adaptive resolution system and method for providing efficient low bit rate transmission of image data for distributed applications

US6829391B2 · kind B2 · utility

Assignee

• Siemens Corporate Research, Inc. · US

Inventors

• Dorin Comaniciu · Princeton Junction, US
• Visvanathan Ramesh · Plainsboro, US
• Fabio Berton · Savona, IT

Key dates

• Filing date: Aug 31, 2001
• Grant date: Dec 7, 2004
• Expiry date: Apr 19, 2023

Classification

• Technology area (CPC G): Physics
• CPC primary: G08B13/19691
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A client-server system and method that enables efficient, low bit rate transmission of image data over a network from an image server (e.g., active cameras) to a client for, e.g., distributed surveillance. A detection and tracking module detects a human presence within an observation area and provides 2-dimensional face coordinates and its estimated scale to a video transmission module. The captured video is then efficiently encoded in log-polar coordinates using an adaptive log-polar mapping, with a foveation point centered on the face. A fovea region, which covers the target object (face), is uniformly sampled and transmitted at full resolution to the client. The periphery region (background) is sampled according to a log-polar grid. To compensate for bit rate variations due to the changes in the scale of the target object and/or bandwidth of the communication channel, the resolution of the periphery region is modified through an adaptive log-polar mapping process, so as to maintain a virtually constant transmission rate from the server to the client. The high resolution of the data in the fovea region enables efficient recognition and/or identification of the transmitted video.