Priority-driven Coding and Transmission of Progressive JPEG Images for Real-Time Applications

Abstract

Since high-quality image/video systems based on the JPEG/MPEG compression standards often require power-expensive implementations at relatively high bit-rates, they have not been widely used in lowpower wireless applications. To alleviate this problem, we designed, implemented, and evaluated a strategy that can adapt to different compression and transmission rates. (1) It gives important parts of an image higher priority over unimportant parts. Therefore, the high-priority parts can achieve high image quality, while the lowpriority parts, with a slight sacrifice of quality, can achieve huge compression rate and thus save the power/ energy of a low-power wireless system. (2) We also introduce a priority-driven scheduling approach into our coding algorithm, which makes the transmission of important parts earlier with more data than other parts. Through a balanced trade-off between the available time/bandwidth/power and the image quality, this adaptive strategy can satisfy users with desired images quality and lead to a significant reduction of the important parts_ deadline misses.

Adaptive Monitoring Relevance in Camera Networks for Critical Surveillance Applications

“…Similarly, the work in [16] proposes an adaptive reduction of energy consumption exploiting DWT image compression, achieving energy saving when adjusting the source coding rate and the error resilience scheme. DWT compression for image transmission was also exploited in [17], where high quality is only necessary for parts of the images with higher relevance for the application, leaving the remaining data with huge compression (and lower quality). In a different way, characteristics of video coding can also be exploited to optimize the network operation.…”

“…Doing so, routers, switchers, or intermediate sensor nodes may differentiate incoming packets, assuring higher priority to visual data traffic from monitoring cells with higher MR. The value for MR may be included in the packet header just before the data payload, incurring in a very small additional overhead, or be used together with other QoS information (as the data coding relevance [17,22]). …”

A Survey on Multimedia-Based Cross-Layer Optimization in Visual Sensor Networks

“…Cheng and Shang [ 22 ] also investigated the JPEG codec in low-power and low-bit-rate wireless networks, exploiting progressive JPEG encoding as in [ 20 ]. In that work a coding strategy that only employs high quality encoding to parts of the image with higher relevance for the application is proposed, leaving the remaining data with huge compression (and lower quality).…”

“…The image-based cross-layer optimization proposed in [ 22 ] is a priority-driven scheduling algorithm. That algorithm schedules for transmission more data from important sub-images, according to the available bandwidth.…”

“…VSN applications can benefit for visual monitoring where priority-based JPEG encoding like the one presented in [ 22 ] is used in source nodes. For example, if applications are monitoring a moving target, such a coding strategy would potentially reduce the bandwidth requirements (and energy consumption) of transmission of less-relevant parts of the scene (as visual data of the sky and the ground), keeping the viewing of the target with high quality for the application.…”