Energy-aware Image Aggregation in Wireless Visual Sensor Networks

VSN is different from traditional WSN that collect and transmit images/video instead of scalar data to the sink. Images provide richer information than scalar data that enable VSN to be a promising technology on security monitoring and surveillance. Image transmission in VSN is expansive due to its large image size and significant energy consumption. One possible way to reduce the image size is to aggregate the received images on the sensor nodes before transmission. By eliminating the redundant image, image aggregation in VSN could transmit the overlapped region of the images only once to reduce the total energy consumption. However, image aggregation requires image processing at the aggregator node that incurs additional node processing energy. In this paper, we study the energy consumption tradeoff between node image processing and image aggregation. We derive the image aggregation energy consumption model that considers the image processing and image transmission. From the simulation results, image aggregation scheme does help lowering the energy consumption. As compared to the non-aggregation scheme, image aggregation scheme consumes only 46% of the energy consumption. In addition, we also find that the threshold for the number of aggregated nodes. Above this threshold, increasing the number aggregated nodes does not help on reducing the energy consumption. This could help determining the number of aggregated nodes under different degree of aggregation to achieve minimum energy consumption.