Image Acquisition, Transmission, Compression And Restoration On Landslide Monitoring System In Wireless Networks

Landslide is a kind of multiple and regional natural geological disasters. The collapse of the mountain and debris flow caused by heavy rain will pose a great threat to the lives and property of residents nearby. Therefore, it is very important to carry on the real-time monitoring to the area where is prone to landslide. In order to enhance the visibility and richness of the information of landslide monitoring, this dissertation designs the WMSNs landslide monitoring system,which uses embedded micro controller STM32F407, OV7670 CMOS image sensor and CC2530short-haul communication module to develop image acquisition node. Meanwhile this dissertation completes the data transmission between image acquisition module and wireless communication module and realizes the communication between the acquisition and sink node.In order to achieve the fast transmission of images under the Zig Bee protocol of the WMSNs internal nodes, by introducing compressive sensing technique, this dissertation uses the sampling rate which is far below the Nyquist sampling rate in site node to realize the acquisition and compression of image. Discrete wavelet transform is used for sparse representation of the images acquired by nodes, and discrete Gauss matrix is selected for signal observation, which can reduce the node transmission data, maintain and enhance the timeliness of landslide monitoring system, and reduce the occupancy of node resources. In order to improve the awareness rate of residents and make them judge the environment themselves, a sink node with WiFi module is developed, which sends messages to residents’ phones directly through the exclusive local WiFi network. Therefore based on the platform of android mobile phone, the mobile client uses orthogonal matching pursuit algorithm to reconstruct an image signal, and the algorithm program is written in the Android applications, which realizes the receiving of image observation data and reconstruction of the original image. In the landslide site author built a monitoring network to carry out experiment of field images’ acquisition, compression, transmission and reconstruction.The testing results show that the acquisition node can successfully capture the image of monitoring area, and then after compression the image is transfered to mobile phone via wireless network. At last, after reconstruction it can display on the phone; The image is clear, and transmission time is about 50% of the original image.