指纹图象的局部纹线周期是预处理中构造滤波函数（如Aabor滤波器）的重要参数，在先求得指纹图象局部纹线方向的基础上，分析了局部纹线周期错误对滤波的影响及造成错误的原因，提出了一种基于数学形态学的准确求取局部纹线周期的方法。该方法在大量试验中取得良好应用效果。

The period of local ridges is a critical parameter to constitute filters (for instance Gabor Filter) used in pre-processing of the fingerprint images. Behind acquiring orientation of local ridges, this thesis analyzes the influence of the wrong period of local ridges upon filtering , and presents a method for accurately extracting the period of local ridges on the basis of Mathematical Morphology . Numerous experimental results show that the method is effective and reliable.

TP391.41 D918.91