Energy-efficient transmission scheme of JPEG images over Visual Sensor Networks

With Visual Sensor Networks (VSN), designers must respect strict constraints on energy consumption, which make compression standards, such as JPEG, not energy-beneficial to VSN. Our approach for tackling this constraint problem consists in adapting JPEG by exploiting the DCT energy compaction property. This exploitation is performed by processing only a portion of each block of 8 times 8 DCT coefficients of the captured image. This approach induces two conflicting effects. Indeed, reducing the size of the portion of DCT block presents the advantage of reducing the energy consumed for processing and transmitting an image, but it also presents the drawback of reducing the quality of the image received at the sink.We propose two methods to solve this conflict: a global method and a local method. In the global method, an optimal size is computed for all portions of DCT blocks of a whole image.