<title>Efficient small target detection algorithm</title>

According to the principle of human discrimination of a small object from a natural scene in which there is the signature of discontinuity between the object and its neighbor regions, we develop an efficient algorithm for small object detection based on template matching by using a dissimilarity measure that is called average gray absolute difference maximum map (AGADMM), infer the criterion of recognizing a small object from the properties of the AGADMM of a natural scene that is a spatially independent and stable Gaussian random field, explain how the AGADMM improves the detectable probability and keeps the false alarm probability very low, analyze the complexity of computing AGADMM, and justify the validity and efficiency. Experiments with visual images of a natural scene such as sky and sea surface have shown the great potentials of the proposed method for distinguishing a small man-made object from natural scenes.