JPH04306777A - Fingerprint characteristic correction system - Google Patents

Abstract

PURPOSE:To simplify the correction work of a left fingerprint which is indispensable to the collation of the fingerprint. CONSTITUTION:A characteristic point is added (step 5) by designating the type and the direction of the characteristic point on a fingerprint picture displayed on a display part by using a mouse and the like. Furthermore, the characteristic point is deleted (step 6) on the displayed fingerprint picture by using a pointing device. Then, a minutial list is generated (step 9) after the characteristic point is added or deleted, and the number of streamlines between the characteristic points in the minutial list is designated so as to complete the minutial list concerned(steps 11 and 12).

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fingerprint feature correction system, and more particularly to a fingerprint feature correction method for improving the quality of a fingerprint stamped on a stamp paper or a latent fingerprint taken from a crime scene.

0002

[Prior Art] In a fingerprint matching device, a collected fingerprint image is compared with a fingerprint image registered in advance.In this case, information such as the position and direction of minutiae, the number of ridges between neighboring minutiae points, etc. Generally, both fingerprint images are compared based on whether they match or do not match.

Many proposals have been made for such fingerprint feature extraction methods, including Japanese Patent Laid-Open No. 138174/1983. In such feature extraction processing, fingerprint ridges are traced for a low-quality fingerprint image such as a latent fingerprint, and then feature points are extracted using this traced figure.

[0004] Furthermore, after feature points are extracted, correction processing such as deleting incorrectly extracted feature points and adding unextracted feature points is essential. Such correction processing has the drawback of requiring a large amount of time and work.

[0005]

OBJECTS OF THE INVENTION An object of the present invention is to provide a fingerprint feature correction system that can extremely easily perform correction processing such as adding or deleting feature points.

[0006]

[Structure of the Invention] The fingerprint feature correction system according to the present invention comprises:
An input means for inputting a fingerprint image to be corrected, a conversion means for converting the input fingerprint image into two-dimensional quantized image data, and a feature for extracting feature points from the converted two-dimensional quantized image data. a point extraction means, a display means for superimposing and displaying the extracted minutiae on the two-dimensional image, and an additional instruction for the type, position, and direction of the fingerprint minutiae on the displayed two-dimensional image; a feature point adding means for adding a feature point in response to a feature point deletion instruction; a feature point deletion means for deleting a feature point on the displayed two-dimensional image in response to a feature point deletion instruction; List generation means for generating a feature point list indicating the position, direction, and number of ridges between neighboring feature points for each feature point after completion of the addition and deletion processing; The present invention is characterized in that it includes a ridge number assignment means for sequentially specifying the number of ridges and assigning it to a portion of the number of ridges between neighboring feature points in the corresponding feature point list.

[0007]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a flow chart showing the operation of an embodiment of the present invention, and FIG. 2 shows the configuration of the present invention.

As shown in FIG. 2, this embodiment includes a fingerprint image input unit 20 that photoelectrically converts a fingerprint stamped on a stamped paper or a latent fingerprint taken from a crime scene, and a two-dimensional quantizer of the photoelectric conversion signal. A/D converter 21 that converts into image data
and an image input control unit 22 that performs input control of the fingerprint image.
an image storage unit 23 that stores two-dimensional quantized image data;
Correction is made by inputting image data from the input section 29 for inputting instructions for the fingerprint image and minutiae displayed on the display section 30, the display section 30 for displaying the fingerprint image and minutiae, and the image storage section 23. and a correction processing unit 28 that performs.

The correction processing unit 28 receives image data from the image storage unit 23 and information regarding the fingerprint image to be corrected from the input unit 29, and has an external interface 24 that outputs the image data to the display unit 30, and a working memory. 27, a program memory 26 in which a program for correction processing is stored, and a central processing unit 25 controlled by the program.

Next, the operation of the embodiment of the present invention will be explained using the components shown in FIG. 1 and according to the flowchart shown in FIG.

The fingerprint image is input from the image storage section 23 to the correction processing section 28 through the interface 24 (step 1). The fingerprint image is input by using a known method, for example, the method disclosed in Japanese Unexamined Patent Publication No. 138174/1983, and the details thereof will be omitted here. Next, fingerprint features such as minutiae pointing to end points and branch points are automatically extracted (step 2). This feature point extraction is also disclosed in the above publication.

The input fingerprint image is displayed as a two-dimensional quantized fingerprint image on the display unit 30 through the external interface 24, and the automatically extracted feature points are displayed superimposed on the fingerprint image (step 13). Display of a two-dimensional quantized fingerprint image can be easily realized using known techniques, so details thereof will be omitted.

When performing correction work on the two-dimensional quantized fingerprint image displayed on the display section 30, the input section 29
Specify the position on the fingerprint to be corrected using a mouse, etc. (Step 3), and if a minutiae is already displayed at the specified position, the minutiae will be deleted (Step 6). On the other hand, if the feature point is not displayed at the specified position, the feature point addition process (step 5) is performed and the feature point is added.

In the feature point addition process, select the type of feature point, ie, end point or branch point, on the feature point type menu screen displayed on the display unit 30 (step 51), and specify the direction of the feature point. (Step 52) adds feature points.

The feature points determined by the feature point addition process and the feature point deletion process are displayed on the display unit 30 via the external interface 24, superimposed on the two-dimensional quantized fingerprint image (step 7). The superimposed display with the two-dimensional quantized fingerprint image can be easily realized using a known technique, so the details will be omitted.

After the feature point addition process or feature point deletion process is completed, a minutiae (feature) list is created for each feature point. Figure 3(a) shows a certain feature point M and its neighboring feature point m1.
This is an example showing the relationship with m4, and FIG. 3(b) is a diagram showing a mechanical list regarding the feature point M.

The manualist determines the position of the feature point M (
X, Y), the pattern direction D, and relations R1 to R4 with neighboring minutiae points, and is a list representation of all the minutiae points that exist in one fingerprint.

The relation is the number of ridges between neighboring minutiae points, and the relation between the neighboring minutiae points mi (FIG. 3(a)
) represents the number of ridges ri between i=1 to 4).

At the end of step 8 of the flowchart in FIG. 1, the number of ridges between neighboring feature points has not yet been determined.
Therefore, in this manualist, ri is blank. Therefore, pairs of neighboring feature points to be substituted for the number of ridges between neighboring feature points are automatically displayed one after another (step 10).
), the operator specifies the number of ridges between neighboring feature points using the input unit 29 using a mouse or the like (step 11).

For example, r2 = 3 is substituted for the feature point M and its paired neighboring feature point m2 in FIG. 3(a). Regarding the setting of this pair of neighboring feature points,
The method disclosed in Publication No. 5-138174, that is, the feature point M is located near the feature point M in each quadrant of the local coordinate system (x-y) determined by its position and direction. A method is used in which each of the feature points m1 to m4 is paired.

[0022] The above processing is performed for all mechanicalists until it is completed (step 12).
, 14).

[0023]

[Effects of the Invention] As described above, according to the present invention, the correction of minutiae can be easily performed using an input means such as a mouse, so the quality of latent fingerprints is improved and fingerprint verification is quick and easy. This has the effect of being accurate.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the operation of an embodiment of the present invention.

FIG. 2 is a system block diagram of an embodiment of the present invention.

[Figure 3] (a) shows a certain feature point M and its neighboring feature point m1
A diagram showing the relationship between m4 and (b) is a diagram showing a manualist.

[Explanation of symbols]

20 Fingerprint image input section 21 A/D conversion section 23 Image storage unit 25 Central processing unit 26 Program memory 27 Working memory 28 Correction processing section 29 Input section 30 Display section

Claims (1)

[Claims] 1. An input means for inputting a fingerprint image of a target to be corrected, a conversion means for converting the input fingerprint image into two-dimensional quantized image data, and a characteristic from the converted two-dimensional quantized image data. a feature point extraction means for extracting points; a display means for superimposing and displaying the extracted feature points on the two-dimensional image; and on the displayed two-dimensional image,
A minutiae adding means for adding minutiae in response to an instruction to add the type, position, and direction of the fingerprint minutiae; and a minutiae addition means for deleting minutiae on the displayed two-dimensional image in response to a minutiae deletion instruction. a feature point deletion means; and a list generation means for generating a feature point list indicating the position, direction, and number of ridges between neighboring feature points for each feature point after the addition and deletion processing by the addition and deletion means is completed; ridge number substitution means for sequentially specifying the number of ridges between feature points for each feature point indicated by the feature point list, and assigning the number to the number of ridges between neighboring feature points in the corresponding feature point list. A fingerprint correction system characterized by: