基于相位相关的指纹拼接方法研究

Research on Method of Fingerprint Mosaicking Based on Phase Correlation

基于指纹图像的旋转、平移、距离等不变特性,从增加指纹图像的有效特征点出发,提出了指纹拼接方法。该方法分为三步:第一步,提出基于中值滤波及局部属性的归一化预处理算法,去除图像噪声和影响相位相关度准确性的频率信息;第二步,图像进行伪极坐标快速傅立叶变换,根据旋转和平移的不变性,利用相位相关对图像进行快速配准;第三步,对配准的指纹图像完成平滑拼接。大量的实验结果证明本方法可以增加有效的指纹图像特征点数量,改善比对效果,计算复杂度较低,可以实现指纹图像的快速拼接。

A method of fingerprint masaicking was advanced according to the image mvanant property of rotation, translation and distance. The composite image generated by mosaicking increased the numbers of effective feature. The method included three steps： media filter and a novel normalization based on image local property as image preprocess were deployed to get rid of noise and the frequency deteriorated the accuracy of phase correlation; the images were registered based on phase correlation after they were transformed to frequency domain by pseudo polar fast fourier transform instead of polar fourier transform; the images were mosaicked smoothly. It is proved by a great deal of experiment results that the algorithm can increase the feature numbers and improve the performance of verification. At the same time, the low complexity of algorithm can realize fast mosaicking of fingerprint images.