JPS62121587A - Fingerprint image input device - Google Patents

Abstract

PURPOSE:To attain the miniaturization of a device, and to reduce a cost by controlling an illuminating means which illuminates in a spot shape, and a switching between the conversion timing of a D/A conversion means, the read/ write timing of an image accumulation means, and the selection signal of a video signal selection means. CONSTITUTION:Light emitted from a lamp 11 is scattered at a mat glass 12, and is condensed with a condenser lens 13, and is irradiated on a sheet of fingerprint input paper 2 as an illumination of spot shape. A television camera 3 image-picks up a fingerprint on the sheet of fingerprint input paper 2, and outputs a video signal of reference system, and the video signal is inputted to an A/D converter 4 and a video selection circuit 7 respectively. At the A/D converter 4, only the video signal part of the video signal, from which a synchronizing signal is eliminated, inputted from a television camera 8 is quantized to eight bits/picture element, and is outputted to a storage circuit 5. Thereby, a mechanical carrying mechanism is made unnecessary, and a small light source for illumination is enough, and the device is miniaturized and inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image data input device, and particularly to an input device for a fingerprint image stamped on paper.

[Conventional technology]

Conventionally, this type of device uses a one-dimensional image sensor with a large number of pixels to collectively input the fingerprints of multiple fingers (usually 10 fingers) stamped on a paper surface, and the main scanning is performed by the one-dimensional image sensor. This is done by self-scanning, and by mechanically conveying the paper or an image sensor, the fingerprint imprinted on the paper is read as a two-dimensional image. An extremely high-precision transport mechanism is used to cut out the fingerprint image, and a long rod-shaped fluorescent lamp or Lighting is provided using a tungsten lamp with a long linear filament.

FIG. 5 is a block diagram showing a conventional example of the above-mentioned fingerprint image input device. This device feeds a fingerprint input paper 22 by a mechanical conveyance system (paper feed roller) 21,
This is used as a sub-scan.

The paper surface is illuminated by a fluorescent lamp 28. The fingerprint image stamped on the paper is connected to a one-dimensional image sensor z5 by a lens z4, photoelectrically converted, and output from the image sensor 25 as an electric signal (video signal).

Here, the image sensor z5 performs an imaging operation based on a drive signal from the control circuit 28, and the video signal from the image sensor 25 is quantized by the FiA/D conversion circuit z6,
The data is input to the memory circuit 27 and stored. The timing of A/D conversion and the timing of writing to the memory circuit 27 are controlled by the control circuit z8 in synchronization with the drive timing of the image sensor 25.
and supplied to each. In addition, the control circuit 2
8 reads out the fingerprint image data stored in the storage circuit 27 in response to a request from an external device (for example, verification device ff1);
Sequential output to external device.

[Problem that the invention seeks to solve]

The conventional fingerprint image input device described above requires a mechanical force transfer system with high transfer position accuracy and a long bar-shaped illumination lamp, making the device large and complicated. has the disadvantage of being expensive.

[Means for solving problems]

The fingerprint image input device of the present invention includes a television camera for capturing a fingerprint image on a paper surface, a means for uniformly illuminating only the field of view of the television camera in a spot shape and brighter than the surrounding area, and an output video from the television camera. A means for A/D converting a signal; an image storage means for storing one screen worth of quantized image data output from the A/D converter; and a D/D converter for the quantized image data read from the image storage means. A
D/A conversion means for converting and outputting the converted video signal as a video signal; video signal selection means for selectively outputting either the output video signal from the D/A conversion means or the video signal from the television camera; and this video signal. A television monitor that displays and outputs the video signal selected and output by the selection means, and controls conversion timing of the D/A conversion means, writing/reading timing of the image storage means, and switching of a selection signal of the video signal selection means. and control means.

Instead of the conventional one-dimensional image sensor and long rod-shaped illumination means, a television camera that captures the fingerprint image on the paper surface,
By providing an illumination means that illuminates only the field of view of the television camera as a spot and uniformly brighter than the surrounding area, a mechanical transport mechanism is not required and the illumination light source can also be small, making the device very easy to use. became smaller and cheaper,
In addition, by illuminating only the effective field of view of the TV camera in a spot shape that is brighter than the brightness of the surrounding area, the input position can be automatically aligned by simply aligning the fingerprint that the operator wants to input with this spot. Very easy to operate.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the fingerprint image input device of the present invention, and FIG. 2 is a diagram showing the configuration of an illuminator 1. As shown in FIG.

In this embodiment, illuminator 1. TV camera 3, A/D converter 4. Memory circuit 5. D/A converter6. Video selection circuit7. It is composed of a television monitor 8 and a control circuit 9, and is used in such a way that an operator places a fingerprint input paper 2 with a fingerprint stamped on it in the field of view of a television camera 3, aligns each finger one by one, and performs input. . The fingerprint image is captured by a television camera 8, quantized by an A/D converter 4, stored in a storage circuit 5, and input to a verification device via a control circuit 9.

D/A converter6. Video selection circuit7. The television monitor 8 is used to confirm the quantized fingerprint image stored in the storage circuit 5 and to align the image at the time of input.

Next, descriptions of individual components and operations will be added.

As shown in FIG. 2, the illuminator 1 includes a lamp 11 and a frosted glass 12. Condensing lens 18. It is composed of an AC power supply 14. The light emitted from the lamp 11 is diffused by the frosted glass 12, condensed by the condensing lens 18, and irradiated onto the fingerprint input paper 2 as a spot-like illumination. The power source 14 may be a DC power source, and the same effect can be obtained by making the glass portion of the lamp 11 a frosted glass instead of the frosted glass 12. The spot size of the illumination on the fingerprint input paper 2 is selected to be the same size as the effective field of view of the television camera 8 (large enough to accommodate the fingerprint image of one finger), and the spot position is made to match the effective field of view of the television camera 8. It is arranged like this. This allows the operator to automatically place the fingerprint they want to input on the spot on the TV camera 8.
This means that the position has been aligned to the effective field of view, making alignment during input very easy. The television camera a images the fingerprint on the fingerprint input paper 2 and outputs a standard video signal.

This video signal is input to A/D converter 4 and video selection circuit 7, respectively. The A/D converter 4 quantizes only the video signal part excluding the synchronization signal from the video signal input from the television camera 8 to 8 bits/pixel and outputs it to the storage circuit 5 (hereinafter, the video signal including the synchronization signal is is called a video signal, and the one without is called a video signal). The memory circuit 5 has a capacity (
The quantized fingerprint image output from the A/D converter 4 is stored in accordance with the write timing and address from the control circuit 9.

Further, in order to check the state of the image stored in the memory port M and the memory circuit 5, a quantized fingerprint image is outputted according to the read timing from the control circuit 9 and inputted to the D/A converter 6. The video selection circuit 7 is an analog switch, and the control circuit 9 selects the video signal from the television camera 8 when inputting a fingerprint image, and selects the video signal from the D/A converter 6 when confirming the input image. is controlled by a switching signal. The video signal selected and output by this video selection circuit 7 is displayed on a television monitor 8. The control circuit 9 also controls the transfer of input fingerprint image data to an external device, such as a verification device, in addition to those described above. When an input request for fingerprint image data is received from an external device, a readout control signal for the storage circuit 5 is generated, and the read fingerprint image data is sequentially output to the external device. Furthermore, the timing for starting storage in the storage circuit 5 and the generation of a switching control signal for the video selection circuit 7 are also generated by the control circuit 9 by decoding a control command from an external device.

FIG. 8 is a block diagram of the A/D converter 4.

The video signal input from the terminal S is sent to the synchronization detection circuit 41.
and is input to the clamp circuit 42. Synchronization detection circuit 4
1 detects a horizontal synchronizing signal in a video signal and outputs a clamp signal based on the detected synchronizing signal. This clamp signal is input to the clamp circuit 2 and the pixel clock generation circuit 48. The clamp circuit 42 performs DC reproduction at the timing of the input video signal sound clamp signal, cuts the synchronizing signal portion, and outputs only the video signal.

On the other hand, the pixel clock generating circuit 48 generates and outputs a 7' spring clock for each pixel in synchronization with the clamp signal. This pixel clock and the DC-regenerated video signal are A
The signal is input to the /D conversion circuit 44, quantized at the timing of the pixel clock, and output as a digital signal from the terminal DS.

FIG. 4 is a block diagram of the D/A converter 6.

The quantized fingerprint image input from the terminal MS is converted into a video signal which is an analog signal by the D/A conversion circuit 61,
In the synchronous synthesis circuit 62, from the control circuit 9 to the terminal VSY,
It is combined with the vertical and horizontal synchronization signals input to H8Y and output as a video signal from terminal VD.

〔Effect of the invention〕

As explained above, the present invention has the following features: Instead of the conventional one-dimensional image sensor and long rod-shaped illumination means, a television camera that captures a fingerprint image on a paper surface, and a spot-shaped field of view of this television camera alone, are used. By providing a lighting means that uniformly illuminates the surrounding areas, there is no need for a mechanical transport mechanism, and the light source for illumination can also be small, making the device extremely compact and inexpensive. By illuminating only the effective field of view in a spot shape that is brighter than the surrounding area, the operator can automatically align the input position by simply aligning the fingerprint they want to input with this spot, improving operability. It has a very good effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the fingerprint image input device of the present invention, FIG. 2 is a diagram showing the configuration of the illuminator 1, FIG. 8 is a block diagram of the A/D converter number, and FIG. is D/A converter 6
FIG. 5 is a block diagram showing a conventional example of a fingerprint image input device. DESCRIPTION OF SYMBOLS 1... Illuminator, 2... Paper on which input fingerprint is stamped, 8... Television camera, 4... A/D converter,
5... Memory circuit, 6... D/A converter, 7... Video selection circuit, 8... Television monitor, 9... Control circuit. Patent applicant: Japan Wtki Co., Ltd., Figure 2, Figure 3

Claims (1)

[Claims] A device for inputting a fingerprint image stamped on paper,
A television camera that captures a fingerprint image on a paper surface, an illumination means that illuminates only the field of view of the television camera in a spot shape and uniformly brighter than the surrounding area, and A/D conversion of an output video signal from the television camera. means and this A/
An image storage means for accumulating one screen worth of quantized image data output from the D conversion means, and a D/A conversion for D/A converting the quantized image data read from the image storage means and outputting it as a video signal. means, video signal selection means for selectively outputting either the output video signal from the D/A conversion means or the video signal from the television camera, and a display output of the video signal selectively output by the video signal selection means. A fingerprint image input device comprising: a television monitor; and a control means for controlling conversion timing of the D/A conversion means, write/read timing of the image storage means, and switching of a selection signal of the video signal selection means.