Point target detection based on nonlinear spatial-temporal filter in infrared image sequences and its analysis

A spatial-temporal detection target method is proposed to detect weak point target with slow velocity in infrared sequences evolving cloud clutter. Frist of all, a temporal filter for detecting point target called triple temporal filter (TTF) is introduced. Since theoretical analysis shows that TTF has a poor performance under temporal noise, a nonlinear spatial-temporal filter by neighbor pixels in prior and posterior frames, which takes every possible target trace account to suppress noise before coming into recursion. Then TTF output by positive and inverse sequence order form nonlinear spatial-temporal filter fuse with liner principle for detecting weak target is put forward, which called bilateral TTF in this paper. Finally its performance is analysis. The results of experiment shows that compared to original TTF, the proposed method achieves a higher signal-to-clutter ratio gain, which is effectively detecting dim target when target signal-to-clutter down to 3 or lower with a low moving velocity.