Aiming at the difficulty of infrared week-dim targets detection with strong background clutter,a novel infrared background suppression algorithm based on surface fitting bidirectional diffusion was proposed,the GaussianFacet model was applied to fit the underlying intensity surface of the infrared week-dim targets image,and integrated directional derivative gradient(IDDG) operator based on Gaussian-Facet model was used to describe the gray-scale character of the image.The analytical bidirectional diffusion ...