An Anisotropic Detection Method of Dim-small Infrared Targets

In order to reduce the bad influence of undulate background in dim infrared targets detection, a new filtering method based on anisotropy is presented. Anisotropic partial differential equations have strong ability to remain direction characteristics, and it can perfectly restrain stable background and preserve undulate background. But we need simultaneously to restrain stable and undulate background, so a few improvements are done in the following. Firstly, we improve the edge stopping function of anisotropic differential, which make it increase following the value of direction grads. Secondly, we choose the two least direction values of edge stopping function as parameter values based on the direction characteristics of grads operator. For that, we are able to simultaneously restrain stable and undulate background, and deal with different characteristic regions respectively. The simulation experiments prove the effectiveness of the proposed algorithm, which detection ability is much better than isotropic filtering methods especially for applying in infrared images with complex background.