Image analysis – Applications – Personnel identification
Reexamination Certificate
1998-07-27
2001-11-27
Boudreau, Leo (Department: 2621)
Image analysis
Applications
Personnel identification
C382S275000, C382S296000, C382S298000
Reexamination Certificate
active
06324297
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a skin pattern feature extracting apparatus for skin pattern images such as fingerprints, palmprints or ridge pattern of other parts of the body.
Skin patterns such as fingerprints or prints of other parts of the body (hereinafter represented by fingerprints), have features that they are “unique for each person” and “stay the same for his/her life time”. Owing to these features of fingerprints, systems have been proposed and implemented for actual use, in which features of a scanned fingerprint image, such as shapes of ridges and positional relations of end points and bifurcations of the ridges known as minutiae, are extracted and matched with reference to enrolled fingerprint features for identifying persons. These systems are highly reliable. To obtain high identification accuracy in these systems, it is necessary to accurately extract positions of end points and bifurcations of ridges from the image.
However, by extracting the above features from the given scanned fingerprints, particularly those having poor quality for such reasons, as that it is a latent fingerprint, in an automated process, it is impossible to realize sufficient accuracy of identification. Therefore, it is necessary that an operator having rich experience displays a fingerprint image, having been read out by a scanner and digitized, on a display screen and input or correct with a mouse or like input means, positions of minutiae, which had not been able to be extracted or erroneously extracted in the automatic process. To support this operation, a “Fingerprint Feature Extraction Apparatus” is disclosed in Japanese Patent Laid-Open Publication No.5-35856. The disclosed apparatus has such functions as:
cutting out an instructed part from an input image including a fingerprint;
subjecting the instructed part to an image enhancing process; and
correcting feature extraction according to instructions.
The images before and after the processes are displayed, thus permitting the above manual feature extraction to be supported. By using this apparatus, the operator does operations of “manual plotting”, i.e., manually inputting position and direction data of end points and bifurcations by watching the display, and “manual tracing”, i.e., manually tracing ridges and inputting the traces.
In many cases of the above manual feature extraction from fingerprints and prints of other parts of the body, when the image as the input image is poor in quality in that it is a latent fingerprint, when the imprint area of the finger print image is small, or when many wrinkles are superposed on an image of a hand skin pattern print image, ridge traces and minute features of end points and bifurcations of the ridges are mixed with noise and can not be clearly observed by the operator.
FIG. 7
shows an example of such an image. In this case, although it is clearly seen that ridges extend together substantially in the horizontal direction, it is considerably difficult to determine the positions of end points and bifurcations. For this reason, even a skilled operator may make person identification with reduced accuracy due to position errors.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a skin feature extracting apparatus, which permits, even with a traced image of poor quality, extracting such features as ridge traces and positions of end points and bifurcations buried in the traces, and improving the accuracy of personal identification.
According to the present invention, there is provided a skin pattern feature extracting apparatus for displaying skin pattern images, comprising: perspective transformation instruction input means for inputting operator's perspective transformation instructions thereto; perspective transforming means for perspective transforming a given image according to the inputted instructions; and perspective transformed image displaying means for displaying the result of the perspective transformation to the operator.
An extent of geometrical image compression of the image in a certain direction thereof and/or an angle of geometrical rotation of the image about a certain point is inputted to the perspective transformation instruction input means. The perspective transforming means executes affine transformation operations on an input image for geometrical image compression thereof in a certain direction and/or geometrical rotation thereof about a certain point.
According to another aspect of the present invention, there is provided a skin pattern feature extracting apparatus for displaying skin pattern images, comprising: focal point instruction input means for inputting operator's focal point instructions thereto; perspective transformation parameter determining means for determining the contents of perspective transformation from the character of an input image in the proximity of the instructed focal point; and perspective transforming means for executing the perspective transformation of the determined contents.
The perspective transformation parameter determining means determines an angle of geometrical rotation in the perspective transformation and/or an extent of geometrical image compression in the perspective transformation with reference to an instructed local image as an input.
The perspective transforming means executes affine transformation operations on the input image according to the rotation angle and compression extent determined by the perspective transformation parameter determining means. The skin pattern feature extracting apparatus further comprises feature data superimposing means for superimposing, on an original image, data of a feature automatically or manually extracted from the original image.
According to other aspect of the present invention, there is provided a skin pattern feature extracting apparatus comprising: image storage means for storing digitized input image; image display means for displaying the input image stored in the image storage means on a display screen; perspective transformation instruction input means for inputting an instruction of a desired perspective transformation of the displayed image; perspective transforming means for generating perspective transformed image by executing an affine transformation according to the data fed from the perspective transformation instruction input means; perspective transformed image display for displaying the perspective transformed image obtained in the perspective transforming means; manual input means, through manual plotting or manual tracing with reference to the perspective transformed image displayed on the perspective transformed image display, for inputting specified position feature data determined based on the manual plotting or manual tracing result to be stored; and feature data transforming means for transforming the stored specified position feature data to feature data for identification of a person in a skin pattern checker.
According still other aspect of the present invention, there is provided a skin pattern feature extracting apparatus comprising: image storage means for storing digitized input image; image display means for displaying the input image stored in the image storage means on a display screen; focal point instruction input means for inputting a position data of a local focal point; perspective transformation parameter determining means, receiving the position data from the focal point instruction input means, for determining perspective transformation parameter data for effectively clarifying the features of the local image area; perspective transforming means for generating perspective transformed image by executing an affine transformation according to the data fed from the perspective transformation parameter determining means; perspective transformed image display for displaying the perspective transformed image obtained in the perspective transforming means; manual input means, through manual plotting or manual tracing with reference to the perspective transformed image displayed on the
Boudreau Leo
McGuireWoods LLP
NEC Corporation
Werner Brian P.
LandOfFree
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