Control-based Adaptive Middleware for Real-Time Image Transmission

Real-time image transmission is crucial to an emerging class of distributed embedded systems operating in open network environments. Examples include avionics mission re-planning over Link-16, security systems based on wireless camera networks, and online collaboration using camera phones. Meeting image transmission deadlines is a key challenge in such systems due to unpredictable network conditions. In this paper, we present CAMRIT, a Controlbased Adaptive Middleware framework for Real-time Image Transmission in distributed real-time embedded systems. CAMRIT features a distributed feedback control loop that meets image transmission deadlines by dynamically adjusting the quality of image tiles. We derive an analytic model that captures the dynamics of a distributed middleware architecture. A control theoretic methodology is applied to systematically design a control algorithm with analytic assurance of system stability and performance, despite uncertainties in network bandwidth. Experimental results demonstrate that CAMRIT can provide robust real-time guarantees for a representative application scenario.

Xiaorui Wang, Huang-Ming Huang, Venkita Subramonian, Chenyang Lu, and Christopher Gill, “CAMRIT: Control-based Adaptive Middleware for Real-time Image Transmission,” IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS 2004) Toronto, Canada, May 2004.


CAMRIT is open-source software. You are welcome to download the current release of CAMRIT 1.0:

To install CAMRIT, you need to


For more information, please email Prof. Xiaorui Wang. This project is a collaborated work with Prof. Chenyang Lu and Prof. Christopher Gill at Washington University in St. Louis.

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