JP2000268162A - Fingerprint image input system - Google Patents

Abstract

(57) [Problem] To transfer image information being acquired by a fingerprint image input device to a monitor device, delete unnecessary information and improve the transfer speed economically. SOLUTION: A fingerprint image picked up by a prism 1 is picked up by an image input unit 3 such as a camera, and a rotation synthesizing unit 5 synthesizes a rotating fingerprint of a finger, stores the fingerprint in an image memory unit 6, and controls image information. This information is sent by the unit 9 to the host computer 12 via the external interface unit 8 and displayed on the display unit 14 thereof. When transferring information to this host computer,
The arbitrary rectangular frame designating means 11 is set so as to extract only the necessary pixels on the screen, and the lower bit truncating means 10 truncates the lower 4 bits of the 8 bits of each pixel to reduce the amount of transfer information. As a result, it is possible to display the synthesized image during fingerprint collection while updating it in a short cycle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fingerprint image input system for collecting fingerprints in digital quantities that are electrically quantized, and more particularly, to a method for collecting a fingerprint while confirming a process of synthesizing a rotated fingerprint on a display device. And a fingerprint image input system.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. Hei 2-171883 discloses a fingerprint image input apparatus which rotates a finger placed on a prism and collects a rotating fingerprint while synthesizing image pickup information. In such a device, the image information being collected is displayed on the display means in order to confirm the collecting operation by the collector, and in the above-described known example, the image information being combined is displayed on the fingerprint image input device. The display is provided on an output unit provided separately via an external interface. In addition, a host computer such as a personal computer equipped with an image storage device is used to control the operation of the fingerprint image input device, store the collected image, and input the name of the subject and the date and time of the image to be attached to the image. However, in this case, the image data collected and synthesized by the fingerprint image input device is transferred to the host computer,
Either a hardware display mechanism such as a video capture and superimpose method is prepared and displayed on the display means of the host computer, or a similar display function is realized by software and displayed on the display means of the host computer.

[0003]

In a fingerprint image input system having a host computer for controlling the operation of a fingerprint image input device and storing a sampled image, if an image being combined is displayed on a display different from the host computer, However, the harvester looks at the two display means, which is not convenient. Also,
The method of sending the data of the image being synthesized to the host computer and displaying it on the display means of the host computer via hardware such as video capture requires extra hardware such as video capture, and the system becomes expensive. is there. Furthermore, when functions such as video capture are realized by software, it is necessary to transfer and update a large amount of image information within a unit of time, especially as the process of synthesizing a fingerprint image is displayed smoothly. The amount of information transfer becomes enormous. Therefore, there is a disadvantage that a host computer having a high display processing capability is required.

An object of the present invention is to provide a fingerprint image input system capable of displaying an image being synthesized on a host computer economically and with sufficient update frequency by improving information transfer efficiency. is there.

[0005]

SUMMARY OF THE INVENTION The present invention provides a prism
A finger is rotated on one surface, and the fingerprint on that surface is sequentially imaged by the imaging means according to an instruction from the host computer and synthesized, and the synthesized image is sequentially stored in the storage means, and the fingerprint is synthesized up to that point during fingerprint collection. In a fingerprint image input system configured to transfer the synthesized image to the host computer and to display the image on the display unit, pixel information of only a part of the screen obtained by the imaging unit necessary for displaying the fingerprint image is obtained. Disclosed is a fingerprint image input system provided with an arbitrary frame setting means for taking out and transferring it to a host computer.

Further, according to the present invention, a finger is rotated on one surface of a prism, and fingerprints on the surface are sequentially imaged and synthesized by an imaging means according to an instruction from a host computer, and the synthesized image is stored in the sequential storage means. In the fingerprint image input system configured to transfer the synthesized image synthesized up to that point during the fingerprint collection to the host computer and display the image on the display unit, a screen obtained by the imaging unit is configured. Disclosed is a fingerprint image input system including a lower bit truncation unit for truncating a predetermined number of bits from the least significant bit from each of a plurality of bits of pixel information and transferring the same to a host computer.

Further, according to the present invention, the finger is rotated on one surface of the prism, and the fingerprint on the surface is sequentially imaged and synthesized by the imaging means in accordance with an instruction from the host computer, and the synthesized image is stored in the sequential storage means. In the fingerprint image input system configured to transfer the synthesized image synthesized up to that point during the fingerprint collection to the host computer and to display the image on the display unit, the fingerprint image of the image obtained by the imaging unit is displayed. An arbitrary frame setting means for extracting the pixel information of only the part necessary for the display, and a predetermined number of bits from the least significant bit from each of the plurality of bits of pixel information extracted by this means. Disclosed is a fingerprint image input system characterized by comprising lower-order bit truncation means for truncating and transferring to a host computer.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a fingerprint image input system according to the present invention. In a fingerprint image input device 16, a triangular prism is used as a prism 1 for collecting a fingerprint, and a light source 2 is used to obtain a clear image. Uses a surface light source. The fingerprint image projected by the prism 1 is converted by the image input unit 3 into an electric signal. A video camera is used for the image input unit 3, and a CCD (solid-state imaging device) is used to convert light into an electric signal. The video camera has a capability of converting 30 frames per second into an electric signal, and a moving image can be obtained by updating this signal. The image information converted into an electric signal by the image input unit 3 is quantized by the image input control unit 4 and converted into a digital signal. The rotation combining unit 5 combines the image information converted into the digital signal with an image while following the rotation of the finger, generates a rotating fingerprint, and stores the fingerprint in the image storage unit 6.
The image input control unit 4, the rotation synthesizing unit 5, and the image storage unit 6 are configured to sufficiently follow the operation speed of the image input unit 3. The information stored in the image storage unit 6 can be retrieved at any time by the image information control unit 9, and the information can be transmitted to the host computer 12 via the external interface unit 8. .

The host computer 12 has a display unit 14 and an input unit 13 for displaying a fingerprint synthesized by the fingerprint image input device 16 and for controlling the operation of the input unit 13 when the user gives an instruction to the input unit 13. It can be configured. A CRT monitor is used for the display unit 14 and the host computer 12
With the control program of the fingerprint image input device 16 that operates above, registration and display of the fingerprint collection status and post-collection information can be performed. Then, the fingerprint image input device 1 is transmitted to the central processing unit 7 via the external interface unit 8 via the external interface unit 8, for example, to start the collection of the rotating fingerprint and to transfer the image information after the completion of the collection.
6 is controllable. The central processing unit 7 interprets the command from the host computer 12 and controls the image input control unit 4, the rotation synthesis unit 5, the image storage unit 6, the image information control unit 9, and the external interface unit 8 to perform the following operations. Realize. (1) Collection of a rotating fingerprint. (2) Notifying the host computer 12 of the completion of the rotation synthesis. (3) The status of collecting the rotating fingerprint is sequentially transferred to the host computer 12 as image information. (4) Transfer the image information after rotation synthesis once.

The control unit of the host computer 12 uses a keyboard, a mouse, and other push button switches. Further, the collected fingerprint (image information) can be stored and stored in a storage medium 15 typified by a hard disk or a magneto-optical disk provided by itself.

FIG. 2 shows a process in which a rotation fingerprint of a finger rotated on the prism 1 is generated in the image storage unit 6 by the rotation synthesis unit 5. The fingerprint collector collects the rotating fingerprint while confirming the position where the finger is placed, the direction in which the finger is rotated, and the speed with the image displayed on the display unit 14 of the host computer 12. The display unit 14 of the host computer 12 updates and displays the information stored in the image storage unit 6 as needed. Therefore, the more the number of update displays per unit time, the more realistic and smooth the moving image is collected by the fingerprint extractor. It is possible to confirm the process.

The factor that determines the number of times of updating and displaying on the host computer 12 is that the ability of the image input unit 3, ie, the video camera, to convert a fingerprint into an electric signal is sufficiently fast at 30 frames per second. 6, the transfer capability transferred via the image information control unit 9 and the external interface unit 8, and the display unit 14 of the host computer 12.
Depends on the ability to display. Therefore, it is conceivable that the image information is compressed using a compression algorithm and expanded by the host computer 12 to improve the transfer capability. However, this method requires the fingerprint image input device 16 to perform high-speed compression. An encoder for executing the algorithm is required, and a decoder for expanding the encoder is also required on the host computer 12 side. As a whole, a high-speed and sophisticated logic circuit must be added, and It is disadvantageous in terms of cost as well as installation.

Therefore, in the present invention, the contents of the information to be transferred from the fingerprint image input device to the host computer are examined, and only the necessary information is transferred to display an image having the required quality and the number of updates on the host computer side. It can be displayed in the section. The first method is a method in which the number of display gradations of an image being combined is reduced and transferred, and the second method is a method in which only a necessary part of data captured by a video camera is transferred. Hereinafter, these will be described in detail.

First, assume that 8 bits are assigned to each pixel of the fingerprint image to express 256 shades of light and shade. 1
The reason why the configuration is 8 bits per pixel is that the video camera used for the image input unit 3 can usually resolve the gradation of 256 or more gradations and the number of gradations is enough to obtain a high-precision image. is there. However, the CRT used for the display unit of the host computer 12 does not necessarily have the ability to express 256 gradations. Since a high-speed update of the display screen is required at a high position, the lower 4 bits of the pixel information expressed in 8 bits by the lower bit truncation means 10 are truncated to form 16 gradations. As a result, first, the transfer information amount can be reduced by half, and sufficient gradation can be obtained for displaying an image being combined. The reason why the truncated information amount of the lower bits is set to 4 bits is that the information transfer unit between the external interface unit 8 and the host computer 12 is usually 8 bits, so that the logic circuit to be configured is simplified. If the transfer is performed in units of 1 bit (serial transfer), a logic circuit that can freely change the information amount from 1 bit to 7 bits can be easily configured.

Next, assuming that the video signal obtained by the image input unit 3 is composed of information of m × n pixels, the coordinates of each pixel can be represented as shown in FIG. Each pixel is stored in the image storage unit 6 as 8-bit information corresponding to its coordinates. In an ordinary television video camera or the like, the image including the prism 1 captured by the image input unit 3 does not necessarily have the same aspect ratio as the image of the prism 1 itself, as shown in FIG. Contains invalid area. Therefore, an arbitrary rectangular frame designating unit 11 is provided in the image information control unit 9.
By transferring only the information within the specified arbitrary rectangular frame from the information stored in the image storage unit 6, the data transfer amount with the host computer 12 can be reduced. In practice, the host computer 12 notifies the fingerprint image input device 16 of the optimal rectangular frame coordinates in advance,
The central processing unit 7 specifies the value to the arbitrary rectangular frame specifying means 11. When transferring an image being rotated and synthesized and its sampling result, only information on pixels located in the designated rectangular frame is transferred, and the information transfer amount for the invalid area is reduced.

In FIG. 4, the image input unit 3 is provided so that all prisms projected as images can be taken in.
In order to absorb the precision of the video camera mounting machine used in the above, a rectangular frame (dotted frame) with a margin is defined.
If a sufficiently large prism is used, this arbitrary rectangular frame may be defined so as to be located inside the prism. When a triangular prism is used as shown in FIG. 1, the imaged prism 1 has a trapezoidal shape, and the amount of information for transferring an invalid area is smaller when an arbitrary trapezoidal frame can be designated than when an arbitrary rectangular frame is designated. Also, it is more efficient to specify an arbitrary shape frame as a method of transferring only the changed part of the image at the time of rotation synthesis, but the specification of a trapezoidal frame or an arbitrary rectangular frame that extracts only the image changed part is more complicated. Requires logic circuits.

As described above, the lower bit truncating means 10 and the arbitrary rectangular frame designating means 1 of FIG.
1 has been described in detail, then the overall operation of the system of FIG. 1 will be described. First, when the host computer 12 gives the central processing unit 7 in the fingerprint image input device 16 a command to collect a rotating fingerprint, the central processing unit 7 controls the image input control unit 4, the rotation synthesizing unit 5, and the image storage unit 6 to operate. Control and start synthesizing the rotating fingerprint. At the same time, the central processing unit 7 instructs the image information control unit 9 to output the rectangular frame designating means 11 so that only the information in the arbitrary rectangular frame of the image information stored in the image storage unit 6 is cut out and transferred. Specify the coordinates of
The arbitrary rectangular frame designating unit 11 cuts out pixel information of the designated rectangular frame from the image storage unit 6, further truncates each lower 4 bits of the pixel information by the lower 4 bit truncating unit 10, and the rest to the host computer 12. Forward. Fingerprint collection is performed while displaying the efficiently synthesized image thus transferred on the display unit of the host computer. In this case, the number of updates can be increased in the image display during the synthesis because the amount of transfer information is reduced, so that the operation of collecting the fingerprint becomes easier than before. Further, the arbitrary rectangular frame designating means 11 and the lower 4 bits truncating means 10 which are means for reducing the information transfer amount can be easily realized by simple software processing, and the cost increase for the present invention is slight, The displayed display processing capacity does not particularly increase.

[0018]

According to the present invention, it is possible to realize a fingerprint image input system capable of displaying a rotating fingerprint collection state at a higher speed without using an expensive image information transfer means operating at a high speed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a fingerprint image input system according to the present invention.

FIG. 2 is a diagram showing a state of collecting a rotated fingerprint.

FIG. 3 is an explanatory diagram of a pixel arrangement in an image storage unit 6;

FIG. 4 is an explanatory diagram of an arbitrary rectangular frame setting method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Prism 2 Light source 3 Image input part 4 Image input control part 5 Rotation synthesis part 6 Image storage part 7 Central processing part 8 External interface part 9 Image information control part 11 Arbitrary rectangular frame designation means 12 Host computer 13 Input part 14 Display part 15 Storage media

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshiki Umino 3-2-1 Sachimachi, Hitachi-shi, Ibaraki F-term in Hitachi Engineering Co., Ltd. (Reference) 4C038 FF01 FF06 FG01 5B043 BA02 CA09 DA05 FA02 5B047 AA25 AB02 BB04 CA14 CB16

Claims (5)

[Claims] 1. Rotating a finger on one surface of a prism,
The fingerprints on the surface are sequentially imaged and synthesized by the imaging means according to an instruction from the host computer, and the synthesized image is sequentially stored in the storage means, and the synthesized image synthesized up to that point during fingerprint collection is sent to the host computer. In a fingerprint image input system configured to transfer and display the image on a display unit, to extract pixel information of only a portion necessary for displaying a fingerprint image from a screen obtained by an imaging unit and transfer the pixel information to a host computer. A fingerprint image input system, characterized in that an arbitrary frame setting means is provided. 2. Rotating a finger on one surface of the prism,
The fingerprints on the surface are sequentially imaged and synthesized by the imaging means according to an instruction from the host computer, and the synthesized image is sequentially stored in the storage means, and the synthesized image synthesized up to that point during fingerprint collection is sent to the host computer. In the fingerprint image input system configured to transfer and display the image on the display unit, a predetermined number of bits from each of the plurality of bits of the pixel information constituting the screen obtained by the imaging unit, starting from the least significant bit A fingerprint image input system comprising a lower bit truncating means for truncating and transferring to a host computer. 3. Rotating a finger on one surface of the prism,
The fingerprints on the surface are sequentially imaged and synthesized by the imaging means according to an instruction from the host computer, and the synthesized image is sequentially stored in the storage means, and the synthesized image synthesized up to that point during fingerprint collection is sent to the host computer. In a fingerprint image input system configured to transfer and display the image on a display unit, an arbitrary frame setting unit for extracting pixel information of only a part necessary for displaying a fingerprint image from a screen obtained by the imaging unit; And a lower bit truncation means for truncating the least significant bit by a predetermined number of bits from each of the plurality of bits of pixel information extracted by this means and transferring it to the host computer. Characteristic fingerprint image input system. 4. The fingerprint image input system according to claim 1, wherein a frame set by said arbitrary frame setting means has a rectangular shape. 5. The fingerprint image input system according to claim 2, wherein when a pixel constituting a screen obtained by the imaging means is 8-bit information, the lower bit truncation means truncates the lower 4 bits. A fingerprint image input system.