Fingerprint registering method and fingerprint checking device

Abstract

The present invention can achieve the reliability and simplicity in registering a fingerprint by indicating the quality of a fingerprint image by the number of pseudo minutiae, improve the security of an entrance/exit control system to register a fingerprint, detect the direction of ridge lines of a fingerprint accurately as much as possible, improve the security in checking a fingerprint remarkably, collect renewed registered fingerprint data by a host device and hold the registered fingerprint data of each gate as the latest fingerprint data, improve the operability by enabling to use identification numbers having the less number of digits, and register a fingerprint having a high match rate by automatically applying spatial filtering in re-registering only. A fingerprint registering method according to the present invention detects normal minutiae and pseudo minutiae in a fingerprint pictured by a fingerprint image pickup unit, counts pseudo minutiae in registering windows with normal minutiae at almost the center, determines the average number of pseudo minutiae in registering windows from a total of pseudo minutiae in all registering windows, and registers a fingerprint when the average number of pseudo minutiae is equal to or below a threshold.

What is claimed is:  
     
         1 . A fingerprint registering method comprising: 
 detecting normal minutiae and pseudo minutiae of a fingerprint pictured by a fingerprint image pickup unit, counting the number of said pseudo minutiae in registering windows with said normal minutiae at almost the center, determining the average number of pseudo minutiae in the registering windows from a total of pseudo minutiae in all registering windows, and registering said fingerprint when said average number of pseudo minutiae is equal to or below a threshold.    
     
     
         2 . The fingerprint registering method according to    claim 1   , wherein when said average number of pseudo minutiae in the registering windows exceeds the threshold, registering of another fingerprint is instructed, and fingers are sequentially registered until a fingerprint with the average number of pseudo minutiae in the registering windows equal to or below the threshold is obtained.  
     
     
         3 . The fingerprint registering method according to    claim 1   , wherein when said average number of pseudo minutiae in the registering windows exceeds the threshold, registering of another fingerprint is instructed, a finger having the minimum average number of pseudo minutiae in the registering windows is selected as the best finger, and the fingerprint of said best finger is registered.  
     
     
         4 . A fingerprint checking device comprising: 
 a fingerprint image pickup unit,    an image processor unit for thinning processing a pictured image by said fingerprint image pickup unit,    a minutia detecting unit for detecting normal minutiae and pseudo minutiae from the thinning-processed image from said image processor unit,    an average pseudo minutia calculating unit for calculating the average number of pseudo minutiae in all registering windows by counting said pseudo minutiae in the registering windows with said normal minutiae at almost the center,    a registering unit for registering a fingerprint,    a judging unit for comparing said average number of pseudo minutiae from said average pseudo minutia calculating unit with a threshold to register the fingerprint in said registering unit when said average number of pseudo minutiae is equal to or below said threshold,    a display unit for showing said average number of pseudo minutiae from said average minutiae calculating unit or information which corresponds to said average number of pseudo minutiae, and    a checking unit for checking the fingerprint registered in said registering unit with the fingerprint pictured by said fingerprint image pickup unit.    
     
     
         5 . The fingerprint checking device according to    claim 4   , wherein said judging unit displays on said display unit instructions for registering another finger when said average number of pseudo minutiae exceeds said threshold, selects a finger having the minimum average number of pseudo minutiae as the best finger when the average number of pseudo minutiae of all fingers exceeds said threshold, and registers the fingerprint of said best finger in said registering unit.  
     
     
         6 . A fingerprint registering method for a system to release a lock by checking an affixed fingerprint with a registered fingerprint, in which fingerprints of a prescribed number of at least two supervisors are registered in a fingerprint registering unit by using a fingerprint registering key, and a person who is next to register a fingerprint registers the fingerprint in said fingerprint registering device by means of the fingerprint registering key and the matching of the fingerprint of at least one of said prescribed number of supervisors who have registered their fingerprints.  
     
     
         7 . The fingerprint registering method according to    claim 6   , wherein when the fingerprint is registered in said fingerprint registering device, an attribute defining an accessible range of persons who register fingerprints is also registered, the fingerprints or said attribute registered in said fingerprint registering device can be renewed or deleted by means of the fingerprint registering key and the registration permission by matching of the fingerprints of said supervisors who have registered their fingerprints.  
     
     
         8 . The fingerprint registering method according to    claim 6    to  7 , wherein when the registered fingerprints of said supervisors are required to be deleted or the attribute is required to be changed, said deletion requirement or the attribute change requirement is rejected if the deletion or the attribute change results in that the remaining number of supervisors who have registered fingerprints becomes one or below the prescribed number.  
     
     
         9 . A fingerprint checking entrance/exit control system for unlocking by checking an affixed fingerprint and a registered fingerprint comprising: 
 a fingerprint registering device for registering a fingerprint and an attribute of a fingerprint registering person,    a fingerprint checking unit for checking the fingerprints registered in said fingerprint registering device with the affixed fingerprint,    a fingerprinting unit, and    fingerprint checking gates containing a control unit for controlling to unlock according to said attribute and the result obtained by checking the fingerprint affixed on said fingerprinting unit and the fingerprint registered in said fingerprint registering device, wherein    said fingerprint registering device registers a fingerprint by fingerprint registering operation by means of a fingerprint registering key and the allowance of registering by checking of the fingerprint of at least one supervisor.    
     
     
         10 . The fingerprint checking entrance/exit control system according to    claim 9   , wherein the functions of said fingerprint registering device are provided on at least one of said fingerprint checking gates to share the structure of at least fingerprinting unit.  
     
     
         11 . A fingerprint checking method for binarizing a multivalued image obtained by picturing an affixed fingerprint into a binarized image, dividing said binarized image into a plurality of blocks, determining the direction of ridge lines in respective blocks, effecting spatial filtering of said multivalued image along the ridge line direction, and binarizing to extract minutiae, wherein 
 respective picture elements in said respective blocks are detected by using a direction detecting mask to find to which of a plurality of directions they belong, the number of picture elements in each of said plurality of directions is determined, the number of picture elements in said respective directions is converted into a vector, the maximum value in values obtained by adding respective direction components on respective vectors is detected, and a direction corresponding to the vector showing said maximum value is judged to be the ridge line direction of said block.    
     
     
         12 . The fingerprint checking method according to    claim 11   , wherein after detecting the ridge line direction of said each block, the average in the ridge line direction of a focused block and a plurality of blocks around said focused block is determined to judge as the ridge line direction of said focused block.  
     
     
         13 . A fingerprint checking method which registers fingerprint data derived from extraction of minutiae from a fingerprint, checks said registered fingerprint data with fingerprint data for checking an affixed fingerprint, and authenticates personal identification if they match, wherein 
 a conversion key number is produced by a previously defined function from an entered key number and the content at a prescribed byte in said registered fingerprint data, said conversion key number is inserted for storing at a prescribed byte in said registered fingerprint data, and    a key number entered at the time of checking the fingerprint is checked with a key number reconstructed from said conversion key number inserted at the prescribed byte of said registered fingerprint data, and the checking fingerprint data obtained from the affixed fingerprint is checked with said registered fingerprint data.    
     
     
         14 . The fingerprint checking method according to    claim 13   , wherein said entered key number and the content at the n-th byte of said registered fingerprint data are added or subtracted to produce a conversion key number, said conversion key number is inserted at the m-th byte of said registered fingerprint data to store in a file, the content at said n-th byte is subtracted or added with respect to said conversion key number inserted at the m-th byte in said registered fingerprint data at checking the fingerprint to reconstruct the key number, and said reconstructed key number is checked with the entered key number.  
     
     
         15 . A fingerprint checking entrance/exit control system comprising a host device which has a file for storing personal information containing an identification number and entrance allowing information and registered fingerprint data in a corresponded form and a gate which has a fingerprint checking unit for storing said personal information and said registered fingerprint data downloaded from the file in said host device and checking with an affixed fingerprint, both connected through a line, wherein 
 the fingerprint checking unit of said gate is provided with a control unit which renews said registered fingerprint data with a time stamp added to said affixed fingerprint data when personal identification is authenticated by checking said affixed fingerprint with said registered fingerprint data, and    said host device collects the renewed registered fingerprint data with the time stamp added of said gate, renews the registered fingerprint data and sends said renewed registered fingerprint data to a gate which is in compliance with entrance allowance information of said personal information.    
     
     
         16 . The fingerprint checking entrance/exit control system according to    claim 15   , wherein said host device has a file which stores first and second registered fingerprint data from a finger registering unit, and a control processing unit, when said second registered fingerprint data is renewed by the latest renewed registered fingerprint data collected from said gate, renews said first registered fingerprint data by said second registered fingerprint data, and transfers said renewed second registered fingerprint data to a gate which is in compliance with said entrance allowing information.  
     
     
         17 . A fingerprint checking device for checking an affixed fingerprint on a fingerprinting unit with registered fingerprint data in correspondence with normal identification numbers stored in a file, characterized by comprising: 
 a local ID file which allocates a local identification number having the less number of digits than said normal identification numbers and stores said local identification number, and    a control unit which reads from said file said registered fingerprint data corresponding to said local identification number entered at the time of checking the fingerprint and checks with said affixed fingerprint.    
     
     
         18 . The fingerprint checking device according to    claim 17   , wherein said local ID file stores said local identification number and effective time information which indicates effective time of said local identification number in a corresponded form.  
     
     
         19 . The fingerprint checking device according to    claim 17    or    18   , wherein said control unit allocates a local identification number which does not overlap with another local identification number registered in said local ID file, and corresponds said registered fingerprint data, which is corresponded with said normal identification number, with said local identification number.  
     
     
         20 . A fingerprint registering method which binarizes multivalued image data obtained by picturing an affixed fingerprint, thinning-processing a binarized image resulting from said binarizing process, extracts minutiae based on the thinning-processed image data through said thinning processing, deletes pseudo minutiae from said minutiae, and when the remaining number of minutiae is equal to or above a prescribed number, registers a fingerprint having minutiae according to said binarized image data, wherein 
 if the fingerprint registering in said process for the first time fails, spatial filtering is effected on said multivalued image data to continue in the ridge line direction in the fingerprint registering process by said process for the second time and following, said spatial filtered multivalued image data is binarized and thinning-processed, said minutiae are extracted from said thinning-processed image data, said pseudo minutiae are deleted from said minutiae, and if the remaining number of minutiae is equal to or more than a prescribed number, the fingerprint having minutiae according to said binarized image data is registered.    
     
     
         21 . The fingerprint registering method according to    claim 20   , wherein to delete said pseudo minutiae, when the extracted minutiae are within a prescribed area, they are judged as pseudo minutiae, and said pseudo minutiae are deleted from a list of minutiae.