农田图像采集与无线传输系统设计

结合ZigBee和GPRS，设计了农田图像采集与无线传输系统。系统由MESH型ZigBee图像采集网络和远程服务器构成，服务器与ZigBee网络的协调器通过GPRS网络进行数据传输。基于V4L技术采集了农田图像，阐述了JPEG压缩和解压缩流程，使用改进的离散余弦变换减小了图像压缩的运算量，并对压缩后的图像作了数据分组和校验，保证了数据传输的可靠性。在选定农田对系统进行实地测试，系统能够顺利采集图像，无线传输成功率为76%，同时分析了传输一幅图像的理论最短时间和实际平均传输时间产生的差异。

Design on System of Acquisition and Wireless Transmission for Farmland Image

Based on ZigBee and GPRS, a system was designed to acquire farmland images and transfer the images wirelessly. The system consisted of MESH-type ZigBee network for image acquisition and a remote server which could communicate with the ZigBee network coordinator via GPRS network. The image acquisition based on the V4L technology was introduced first, and the process of JPEG compression and decompression was described, the method of reducing the computational complexity of image compression by the improved discrete cosine transform (DCT) was studied, then how to improve reliability in the data transmission by partitioning and checking image data was discussed. At last, the system was tested in the given field and it proved that the successful rate of farmland image acquisition was 76%. Furthermore, the difference between the theoretical and practical transmission time was analyzed.