The method firstly selected Fourier spectrum energy ratio and gray contract which were extracted from fingerprint image sub-blocks to construct feature vectors,and then classified these feature vectors by linear support vector machine,finally performed morphological operations to ultimately realize fingerprint image segmentation.

Multi-spectral image fusion to increase gray level ratio between crop and weeds in image;

They are modified gray comparison method,point sharpness algorithm,squared-gradient focus function,wavelet transform method.

Adaptive threshold binarization of infrared image based on the characteristic of grey scale grads between target and background is proposed in this paper.

Prior knowledge of the vehicles,such as shadows underneath the vehicles,rich edge information,contour symmetry,gray level symmetry,horizontal line symmetry and etc,is combined.