Dim target can be regarded as transient signal with unknown intensity and location, and it belongs to high frequency part of the image. By multi resolution wavelet transform for the image, dim target in the condition of low SNR could be detected.

• 将弱小目标看作是红外图像中灰度和位置均未知的暂态信号 ；通过对图像信号作多尺度的小波变换 ；可以在低信噪比条件下检测出弱小目标 .