JP3058176B2 - Fingerprint image input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] Regarding control of the state of imprinting on a finger of a sampling target when a fingerprint image is sampled, a fingerprint input by actively controlling the pressing state of the finger of the fingerprint sampling target An object of the present invention is to provide a fingerprint image input device capable of securing the reproducibility of an image and improving the accuracy of fingerprint collation. In a fingerprint image input device for collecting a fingerprint image from a finger pressed on a fingerprint input surface, Equipped with a printing state detection device that detects the printing state of the finger on the fingerprint input surface at a plurality of positions and determines the quality of the printing state in each detection device, and is arranged around the fingerprint input surface and the printing state at each detection position A determination result transmitting device that visually transmits the determination result to the collection target person by a non-verbal message for each detection position is provided on an extension line connecting each detection position from the center of the fingerprint input surface, and the fingerprint collection target It is configured to transmit the state of impression of the finger.

[Industrial application field] The present invention relates to a fingerprint image input device, and more specifically,
The present invention relates to control of the state of imprinting of a finger of a person to be collected when a fingerprint image is collected.

In recent years, with the introduction of computers into a wide range of social systems, there has been an increasing interest of stakeholders in how to ensure system security (security).

Conventionally, ID cards, personal identification numbers, passwords, and the like have been used as personal identification means when entering a computer room or using a terminal device, but many questions have been raised in terms of ensuring security.

On the other hand, fingerprints are considered to be the most powerful means of identity verification because they have two major characteristics: "everyone is unidentified" and "lifelong invariant". R & D is ongoing.

[Prior Art] Conventionally, a fingerprint matching device using a fingerprint image has been put to practical use as a personal recognition system.

The fingerprint is a concavo-convex pattern including valleys and ridges. When the finger is pressed against one surface of the transparent flat plate, the valleys do not contact but the ridges do. By irradiating the finger pressed by the transparent flat plate with light from the light source through the transparent flat plate, the light is reflected and scattered on the surface of the finger and inside the transparent flat plate. Since the scattered light from the valley of the finger once passes through the air and enters the transparent flat plate, there is no component that is totally reflected and propagated in the transparent flat plate. On the other hand, the scattered light from the ridge of the finger is directly incident on the transparent plate as a spherical wave from the finger, and a part of it satisfies the condition of total reflection in the transparent plate and repeats total reflection in the transparent plate. While propagating. By forming an image of this total reflection component with an appropriate optical system, an image pattern of the ridge portion of the finger can be obtained.

The configuration of the main part of the conventional fingerprint matching device will be described with reference to FIGS. 5 and 6. FIG.

In FIG. 5, the fingerprint collection target person using the collation system puts the finger 2 on a transparent flat plate such as glass. By irradiating the finger 2 with the light of the light source 3 in this state, a ridge pattern of the fingerprint is obtained according to the above-described principle. The optical information is converted into an electric signal by a photoelectric conversion device 4 such as a CCD image sensor, and is then input to a discrimination device 5. The determination device 5 performs density determination at a plurality of positions in the fingerprint image to determine whether the input fingerprint image is valid as an image to be collated and whether the fingerprint image has been normally collected. If the density at each position satisfies a preset reference density range, it is assumed that a fingerprint image has been normally collected. These density detection positions are set, for example, diagonally from the center of the fingerprint image as shown in FIG. 6A, or are set on radiation from the center of the fingerprint image as shown in FIG. 6B. You. According to the control of the discriminating device 5, the display device 6 displays, for example, a light-emitting diode.
The stage of the collecting operation is displayed and transmitted to the fingerprint collecting target person, such as "waiting for input" → "collecting" → "collection completed". If the densities at a plurality of positions do not satisfy the preset reference density range, a re-seal is requested in the display state of "waiting for input".
When a fingerprint image that can be collated is obtained, the determination device 5 sends the fingerprint image to the processing device 7. The fingerprint matching algorithm is executed in the processing device 7, and the matching of the collected fingerprint is completed.

By the way, in such an apparatus, it is important to appropriately obtain a fingerprint image as the original information. However, if the pressing of the finger 2 to the transparent flat plate 1 is not uniform, the ridge pattern is lost, and And various problems such as a change in the thickness of the ridge pattern.

And these problems complicate the image processing process,
This is a major cause of lowering the matching rate of the fingerprint matching system.

In other words, the key issues for improving the accuracy of fingerprint collation are techniques for contacting a finger with an accurate position and techniques for transmitting the contact state of a finger to a fingerprint sampling target so that the finger can be brought into contact with an accurate position. become.

[Problems to be Solved by the Invention] However, in the conventional apparatus, although it is possible to request the reprinting of the fingerprint collection target person, it is considered that the reason for the reprinting request is indicated and the improvement of the printing operation is instructed. In some cases, the stamping request may be repeated multiple times.

The present invention has been made in view of such a problem, and secures the reproducibility of a fingerprint image to be input by positively controlling the pressing state of a finger of a fingerprint collection target person, and improves the fingerprint matching accuracy. It is an object of the present invention to provide a fingerprint image input device that can be improved.

[Means for Solving the Problems] FIG. 1 is a block diagram showing the principle of the present invention.

The printing state detection device 8 detects the printing state of the finger 2 on the transparent flat plate 1 at a plurality of positions, and determines the quality of the printing state at each detection position. The result of the stamping state determination at each of these detection positions is transmitted to the sampling target person at each of the detection positions via the determination result transmission device 9.

[Operation] The impression state detecting device 8 detects the impression state of the finger 2 on the transparent flat plate 1 based on the density at a plurality of positions on a sampled image or based on the pressure at the plurality of positions on the transparent flat plate 1. To detect. Then, the image density and the pressure at each of these detection positions are compared with a preset reference value to determine the quality of the imprinting state at each of the detection positions. The result of the determination of the impression state at each of the detection positions is transmitted to the sampling target person by means of a light emitting display means, a message display means, etc. provided in the determination result transmitting device 9 and uniquely corresponding to each detection position.

With this configuration, the stamping status is fed back to the sampling target person, so that the sampling target person can accurately grasp the stamping status, understand the cause of the reprinting request, and respond appropriately to the reprinting request. Can be. As a result, it is possible to greatly improve individual differences in pressing in the fingerprint imprinting state, and it is possible to increase the accuracy of fingerprint collation.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a configuration diagram showing a main part of one embodiment of the present invention. In the figure, a rectangular reading area 11 is formed of a transparent flat plate, and a finger guideline 12 indicates a portion to be touched by a finger.
Is displayed. An area surrounded by the finger guideline 12 is a fingerprint image capturing area 13, each of which is equidistant from the center in the diagonal direction of the rectangular reading area 11 intersecting at the center P of the xy coordinates in the fingerprint image capturing area 13. As shown by hatching the quadrant positions, four density detection areas 14 are provided. The outer periphery of the reading area 11 is surrounded by a rectangular display device 15. At each corner of the display device 15, a light-emitting display element 16 such as a light-emitting diode (LED), which is selectively driven to light according to the detection result of each density detection area 14, is provided. These light emitting display elements 16 function as a determination result transmitting device.

In such a configuration, the finger guideline 12 is for maintaining reproducibility of the position of the finger, and the fingerprint collection target person touches the finger to the reading area 11 along the finger guideline 12. In addition, instead of such a visual finger guideline 12, a guide may be formed by modeling. Then, each density detection area 14 in the fingerprint image collection area 13 is
Are detected and compared with a preset reference value of the density, and when these detected densities are in an appropriate range, the light emitting display element 16 provided in the display device 15 is selectively driven to light. Then, the state of the impression is transmitted to the fingerprint collection target person. As such an embossing state detecting device, the density detecting function of the conventional discriminating device can be diverted.

As is apparent from these, the density detection region 14 where the light emitting display element 16 does not light indicates that the density is inappropriate, so that the fingerprint collection target person can obtain all the light emission provided on the display device 15. By adjusting the impression state of the finger so that the display element 16 is turned on, an appropriate impression state can be obtained. In addition, by providing the density detection area 14 in each quadrant of the xy coordinate, a stable image can be obtained.

In the embodiment of FIG. 2, the density detection density 14 and the light-emitting display element 16 are provided in each quadrant of the xy coordinates, but as shown in FIG. By providing four density detection areas 14 on the intersecting xy coordinate axes,
A rectangular display device on the outer periphery of the reading area 11 extending the y coordinate axis
Four light-emitting display elements 16 may be provided on 15.

Further, as shown in FIG. 4, three density detection areas 14 are provided at equal distances from the center P in the fingerprint image collection area 13, and three light emitting display elements 16 are provided on the display device 15 near them. May be. By reducing the number of density detection areas 14, the circuit configuration is simplified and the processing time can be reduced.

However, the concentration detection area 14 is not limited to these positions and numbers, and may be appropriately increased or decreased at an arbitrary position in the fingerprint image collection area 13.

[Effects of the Invention] As described above in detail, according to the present invention, a good interface can be obtained between the fingerprint collection target person and the device with respect to the finger pressing state, and the finger pressing state of the fingerprint collection target person can be obtained. , The reproducibility of the input fingerprint image can be ensured, and the fingerprint image input device capable of improving the accuracy of fingerprint collation can be provided.

[Brief description of the drawings]

1 is a block diagram showing the principle of the present invention, FIG. 2 is a diagram showing a main part of one embodiment of the present invention, FIGS. 3 and 4 are diagrams showing main parts of another embodiment of the present invention, FIG. 5 is a diagram showing a main part of a conventional fingerprint matching device, and FIG. 6 is an explanatory diagram of a conventional density detection position. In FIG. 1, 1 is a transparent flat plate, 2 is a finger, 8 is an impression state detecting device, and 9 is a judgment result transmitting device.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model 63-1260 (JP, U)

Claims (3)

(57) [Claims] 1. A fingerprint image input device for collecting a fingerprint image from a finger pressed on a fingerprint input surface, wherein a state of imprinting of the finger on the fingerprint input surface is detected at a plurality of positions, and the quality of the imprinting state of each detection device is determined. A determination result transmitting device, which is provided around the fingerprint input surface and includes a non-verbal message to visually notify the user of the sampling status at each detection position by a non-verbal message. A fingerprint image input device, which is provided on an extension line connecting each detection position from the center of the fingerprint input surface to transmit the state of impression of the fingerprint of the fingerprint collection target person. 2. A fingerprint image input device for optically collecting a fingerprint image from a finger pressed on a transparent flat plate, wherein a state of imprinting of the finger on the transparent flat plate is detected at a plurality of positions, and the quality of the imprinting state at each detection position is determined. It is equipped around the fingerprint input surface of the transparent flat plate, and visually transmits the impression status judgment result at each detection position to the sampling target person by a non-verbal message at each detection position. A fingerprint image input device, wherein a determination result transmitting device is provided on an extension line connecting each detection position from the center of a fingerprint input surface, and transmits a state of imprinting of a finger of a fingerprint collection target person. 3. The fingerprint image input device according to claim 1, wherein a light emitting diode is used as the determination result transmitting device.