Recognition technology of large-scale hybrid-distortion target

In this paper, area-polar algorithm is firstly proposed to solve the problem of hybrid-distortion target recognition technology. This method makes area transform and polar coordinate transform for both target and template, based on the surjective function relationship between the scale and the area of similar figures and the invariance of rotation of polar coordinate. Applied on hybrid optoelectronic joint transform correlator, a combined method can achieve large-scale hybrid-distortion target recognition, which includes area-polar algorithm and edge extracting process based on morphological dilation. Presented with examples of planes, The optical correlation experiments show that this method can enhance the brightness of the correlation peaks for hybrid-distortion target, which possesses large hybrid-distortion tolerance (with 0°~100° rotation distortion tolerance and 100%~200% scale distortion tolerance), and expands the scope of target recognition. The hybrid-distortion target recognition capability by this method is better than by Log-polar transform algorithm, and also better than by synthetic discriminant function and by derivative methods, besides its time complexity is far less than synthetic discriminant function's and derivative methods'.