The invention relates to a method and apparatus for detecting 
infrared dim small targets under a complex background, belonging to the technical field of 
infrared target detection. At first, the invention adopts a bilateral filtering 
algorithm to preprocess the single-frame 
infrared images in an 
image sequence successively, so as to reduce 
noise interference in the image and enhance the 
signal-to-
noise ratio at the target; then, a single-frame infrared target detection 
algorithm based on block extremum is used to detect the 
potential candidate target sets in each preprocessed 
image frame by frame; based on the spatio-
temporal continuity of small targets in multi-frame images, a pipeline filtering 
algorithm is used to identify the possible real targets in the candidate target set; finally the 
false alarm removal strategy is used to eliminate the false target and finally confirm the true target. Through the process, the invention overcomes the shortcomings of weakening target intensity, blurring edge, enlarging contour and the like brought by the prior 
infrared image processing technology, and can better retain and enhance the dim 
small target information, improve the target detectionrate, and reduce the missed 
detection rate and 
false alarm rate of the target.