Research On Image Processing Algorithm For Forest Fire Monitoring Based On WMSN

Forests are important natural resources in ecosystems,forest fires pose a serious threat to the natural environment,biodiversity and economic security.Fire has the characteristics of spreading,in order to avoid the greater impact on the forest,it is very important to find out the fire as soon as possible by developing and utilizing the advanced technology to monitor the forest fire.Wireless multimedia sensor network is a new technology,which can be used in forest fire monitoring and related activities,it consists of a small and low cost sensor node with sensing,processing and wireless communication capabilities and has the characteristics of wide coverage and low cost.Due to the large space environment and the complexity of the forest,the introduction of image sensor nodes is helpful to achieve intuitive and accurate fire monitoring.However,the sensor nodes have limited energy and limited computing resources,which limits the ability of image processing.Therefore,how to reduce the use of memory and energy consumption in the image processing technology has become a hot and difficult point in the research of WMSN.According to the practical needs of forest fire monitoring based on wireless multimedia sensor network,in this paper,an algorithm is proposed to reduce the energy consumption under the premise of ensuring the accuracy and image quality.The main tasks are as follows:(1)Flame detection method based on WMSNBecause of the limited resources of WMSN,the randomness and small probability of forest fire,the large amount of image information of image sensor node and so on.A flame detection algorithm based on the motion characteristics and the temporal and spatial characteristics of color is proposed in this paper.This method directly processes the image data collected by the image sensor nodes at the node end,then the concerned information is transmitted to the gateway,so as to achieve the purpose of reducing the network transmission energy.Firstly,the algorithm eliminates the interference of the static flame like object by using the moving object detection algorithm and obtains a more accurate moving target area to reduce the processing amount of the following steps;Secondly,by analyzing the correlation between the I foreground region and the S foreground region of the flame sequence samples and non-flame sequence samples obtains color space-time characteristics of flame to determine the threshold of flame.Finally,calculating the correlation coefficient between the I foreground and the S foreground of the current moving region,and comparing it with the threshold.When it is greater than the threshold value,the current motion area contains the flame,then it is transmitted to the monitoring center through the multi hop mode.Otherwise,the current motion region is not sent.The experimental results show that the algorithm can detect flame accurately and quickly,and only send the area which is confirmed as the flame to the monitoring center for alarm,thus,the transmission and energy consumption of redundant data in the network are reduced.(2)Image coding method based on WMSNBecause the image data contains a lot of redundant information,the direct transmission to the gateway will consume too much energy.On the basis of SPIHT algorithm,this paper proposes an improved algorithm based on the strip buffer and state flag.After removing the redundant information in the image,the algorithm only transfers a small number of bits to the gateway.Firstly,the image is divided into several bands,and each band is transformed into wavelet transform which enhances the 9/7,then put it into the strip buffer;Secondly,the important sign of wavelet coefficients is put into the state flag.then by scanning the state flag,the output stream is obtained,and the strip buffer is released to store the wavelet coefficients;By analogy,until the image is completely encoded,the node starts the next image processing.The experimental results show that this algorithm greatly reduces the transmission of redundant information in the network,and has a smaller memory footprint and faster processing speed,effectively reduces the energy consumption.