基于时频分析的成像小弱运动目标检测方法

针对传统空时域滤波器难以剔除杂波(尤其是杂波边缘)的缺点，提出了一种基于时频分析的弱小运动目标检测方法。理论分析表明，目标经过处的时频是一个小波包，波包的幅度与目标的幅度一致，而宽度则与目标速度成反比关系；杂波边缘经过处的时频则是一个上坡或者下坡。采用两级滤波方法检测运动目标，即首先采用恒虚警率准则过滤噪声，然后再利用目标出现处存在的波包，分别统计主瓣与旁瓣能量及其能量比，去除杂波，检测出运动目标。云背景下弱小目标检测试验结果证明了该方法的有效性。

Dim moving target detection method based on time-frequency analysis

For it is hard to remove clutters, especially the clutter edge, with conventional high-pass filters in spatial or temporal domain, a dim moving target detection method based on the time-frequency characters of target, noise and clutter is presented. Theoretical analysis shows that the magnitude at the target location in time-frequency domain is a small wave packet, whose magnitude is consistent with the target amplitude, and width is inversely proportional to target speed; the magnitude at clutter edge in time-frequency domain is an uphill or downhill. This target detection method uses two-stage filtering to detect dim target. At first, a threshold based on false alarm ratio criteria in time-frequency domain is adopted to remove noise, and then the energy ratio between main lobe and side l