Progressive compression and transmission of images: Experimental evaluation over Visual Sensor Networks

The performance of the progressive compression and the transmission of images over Visual Sensor Networks (VSN) has been experimentally evaluated. This was performed through a real testbed based on Imote2 sensors and an IMB400 camera. In fact, by using the Progressive-JPEG (P-JPEG), an image was encoded into several scans. When the image is being sent, these scans are transmitted one by one, providing the observer with a gradual coarse-to-fine view of the image. This helps reducing the energy consumption of the whole network as well as the display time of the visualized image at the base station. For that purpose, a VSN testbed based on Imote2 and IMB400 nodes was developed. To provide P-JPEG compression capabilities and to support the IMB400 camera node, TinyOs applications were developed. Extensive sets of experiments were conducted to show the efficiency of P-JPEG over the baseline JPEG.