A method for automatic infrared point target detection in a sea background based on morphology and wavelet transform

A method is developed for the detection and segmentation of spot targets at sea surface. Firstly, the Sea-Sky-Division-Line (SSDL), close to the horizon, is detected by wavelet-transform to mark out the Target Potential Region (TPR), which can reduce the target searching range. A Row average grayscale subtraction (RAGS) operation is employed to correct the blur caused by the non-linearity distribution of the temperature field. To repress the clutter in the background and increase the SNR of the image, a morphology Top-Hat filter is utilized. Then, the image is opening by selecting a proper structuring element to acquire a few potential target points. Through searching the maximal intensity and determining a threshold, most of the false alarms can be eliminated and the doubtful targets can be segmented. When the SSDL is visible, the real point-target can be retained according to the TPR and the false target can be discarded. Under the conditions of invisibility of SSDL for it is outside of the image or it is obscure due to the weather, the segmented target is the real target. The experiment results show that the method can effectively detect and segment infrared point target in complex sea background.