At first , the paper confirms singular area by singular detection , then designs a series of low - pass filters that have different templates according to the different position in finger image for a local area , at last sets up gabor filter parameters according to the characteristics of fingerprint image . the improved enhancement algorithm has a better robust , and can preserve texture structure of singular area effectively . in binary noise clearance , the paper presents an algorithm that clears the biggish white speckles and black speckles 在指纹图像增强方面,本文针对传统的基于gabor滤波器指纹图像增强算法鲁棒性差以及通常会改变奇异区纹理结构的缺点,对原有算法进行了一些改进:首先通过检测奇异点确定奇异区,然后根据局部区域在指纹图像中的位置构建相应取值方式的低通滤波器并对该局部区域方向图进行滤波,最后根据指纹图像纹线的特点对gabor滤波器参数进行设置。
Methods in space / frequency domain : a group of gabor filters are used in texture - based image retrieval ; by analyzing how the energy changes with the decomposing of wavelet , tree - structured wavelet transform in texture - based image retrieval is selected to use . as for similarity measurement of texture - based image retrieval , this paper demonstrates two data models related to the similarity measurement and proposes two kinds of multi - feature combination structures 在空间频域联合的方法中，将构造的一组gabor滤波器用于图象纹理检索；通过分析纹理图象经过小波分解后的能量变化特点，提出了选用树型小波分解方法用于纹理检索，提高了检索的有效性。
Though some persons have presented the idea to use gabor for edge detection before , they only gave the one - dimensional ( 1d ) gabor filter - based edge detection method for step edge . this paper not only gives the two - dimensional ( 2d ) gabor filter - based edge detection method for step edge , also the one - dimensional ( 1d ) method for ramp edge 虽然有人已经对这种方法有过阐述，但其只对一维阶跃边缘作了分析，本文在此基础上，提出了二维阶跃边缘的最佳gabor滤波器设计方法，同时，提出了斜坡边缘模型，给出了一维斜坡边缘的最佳gabor滤波器设计方法。
In the part of image preprocessing , a segmentation algorithm for fingerprint image based on the information of gradient orientations was programmed . according to the uniformity and partial parallarity of ridges and furrows of fingerprint , a model of gabor filter was established to enhance fingerprint image . since two - dimensional gabor filter could be separated into two one - dimensional filters , the complexity of the algorithm could be reduced efficiently 在图像预处理方面,利用指纹图像梯度特性进行图像分割,根据指纹纹线间距均匀且局部平行的特点,建立了用于指纹图像增强的gabor滤波函数物理模型,并将二维gabor滤波分解为两次一维滤波,有效降低了算法的复杂度。
Then adjust the parameters of gabor filter using the orientation and average ridge frequency at each pixel to realize adaptive filtering . the unrecoverable region is segmented based on orientation certainty . experimental results show a very good visual enhancement effect 求出每个象素点处的纹线方向和方向一致性，以及纹线的平均频率，用方向和平均频率调节gabor滤波器对每个象素点进行自适应滤波，并利用方向一致性分割出不可恢复区域，实验表明具有很好的增强视觉效果。
