Abstract: An exact estimation of fingerprint ridge distance is very important for fingerprint image segmentation,enhancement and minutiae feature extraction.An estimation method of fingerprint ridge distance based on ridge orientation projection signal spectrum analysis is proposed to overcome some shortages in the present literatures.Firstly,this algorithm selectively smoothes the fingerprint block orientation field to remove noises,and then computes the Fourier transform power spectrum of projection signal and extracts the fundamental frequency by spectrum analysis to estimate ridge distance.Experimental results prove that the estimation method of ridge distance is precise and reliable compared with other approaches.

Key words: fingerprint ridge distance, orientation field smoothing, spectrum analysis, image segmentation

摘要： 准确估计指纹纹线间距对指纹图像分割、增强及指纹细节特征提取具有重要意义。针对现有纹线间距估计方法存在的不足,提出了一种基于纹线方向投影信号谱分析的指纹纹线间距估计方法。该方法首先对指纹块方向图进行选择性平滑以滤除噪声干扰,然后计算方向投影信号的傅立叶变换能量谱,并通过谱分析提取信号基频,以此估计出纹线间距。实验结果表明,与现有的一些典型方法相比,该文方法对于纹线间距的估计更为准确、可靠。

关键词: 指纹纹线间距, 方向图平滑, 谱分析, 图像分割