相变图在稀疏微波成像变化检测降采样分析中的应用

Application of Phase Diagram to Sampling Ratio Analysis in Sparse Microwave Imaging Change Detection

相变图是稀疏微波成像雷达性能评估的一种重要方式,它可以准确刻画出雷达成像性能随稀疏度、采样比和信噪比3个参数的变化趋势,给出不同参数组合下场景准确重建的概率值。稀疏微波成像变化检测中,由于场景的变化相对于整个观测区域是稀疏的,利用分布式压缩感知方法可以在采样比组合满足一定条件下准确提取场景变化量。该文在场景稀疏度和信噪比不变的情况下,研究前后观测数据的采样比对变化检测结果的影响,绘制稀疏微波成像变化检测相变图,并利用相变图分析变化检测结果随前后两次观测的采样比参数的变化趋势,确定可以实现准确重建的采样比参数组合范围。最后通过仿真和实验验证相变图用于分析稀疏微波成像变化检测结果的可行性和有效性,为实际稀疏微波成像系统降低数据采集量和系统设计复杂度提供依据。

Phase diagram is an important method to evaluate sparse microwave imaging radar performance. Phase transition boundary can characterize the trend of accurate recovery rate visibly and clearly in terms of varied SNR, sparsity and sampling ratio. In sparse microwave imaging change detection, the small variation can be accurately extracted from multiple observations using distributed compressed sensing theory for the sparse scene. Phase diagram is introduced to evaluate the performance of change detection in different sampling ratio under the conditions that the sparsity and SNR has little change. Phase diagram can be used to describe the trend of phase transition boundary and to determine the data collection bounds. Furthermore, a series of simulations and experiments are conducted to verify the practicability of phase diagram. It is available to reduce the measurements and complexity of the sparse microwave imaging system.