Department of Electrical and Computer Engineering, University of Patras, Rio 26500, Greece.
Sensors (Basel). 2010;10(8):7170-91. doi: 10.3390/s100807170. Epub 2010 Jul 29.
In this article a scheme for image transmission over Wireless Sensor Networks (WSN) with an adaptive compression factor is introduced. The proposed control architecture affects the quality of the transmitted images according to: (a) the traffic load within the network and (b) the level of details contained in an image frame. Given an approximate transmission period, the adaptive compression mechanism applies Quad Tree Decomposition (QTD) with a varying decomposition compression factor based on a gradient adaptive approach. For the initialization of the proposed control scheme, the desired a priori maximum bound for the transmission time delay is being set, while a tradeoff among the quality of the decomposed image frame and the time needed for completing the transmission of the frame should be taken under consideration. Based on the proposed control mechanism, the quality of the slowly varying transmitted image frames is adaptively deviated based on the measured time delay in the transmission. The efficacy of the adaptive compression control scheme is validated through extended experimental results.
本文提出了一种在具有自适应压缩因子的无线传感器网络（WSN）中进行图像传输的方案。所提出的控制架构根据以下因素影响传输图像的质量：（a）网络内的流量负载和（b）图像帧中包含的细节级别。给定一个近似的传输周期，自适应压缩机制应用基于梯度自适应方法的可变分解压缩因子的四叉树分解（QTD）。对于所提出的控制方案的初始化，设置期望的传输时间延迟的先验最大界限，同时应考虑分解图像帧的质量和完成帧传输所需的时间之间的折衷。基于所提出的控制机制，根据测量到的传输时间延迟，自适应地偏离传输的慢变图像帧的质量。通过扩展的实验结果验证了自适应压缩控制方案的有效性。
