JPS6128175A - Image input device - Google Patents

Abstract

PURPOSE:To decide starting timing of a photoelectric conversion process for the purpose of taking an image automatically with a simple constitution by controlling the starting of taking stripe pattern based on an average value of a light and shade level of an image signal, constantly scanning the central part of the stripe pattern. CONSTITUTION:An input unit 1 is controlled by an input timing process circuit 2 and a scanning line 13 near the central part of a stripe pattern 12 is constantly scanned, and when an average value of a light and shade level of an image signal by scanning exceeds the fixed threshold value, the circuit 2 decides that a finger of an object to be checked, has been laid on the laying surface of a reflection surface of prism, and the designated signal of a timing signal for starting a whole scanning is supplied from the circuit 2 to the unit 1 to conduct automatic starting of a photoelectric conversion process of the whole finger print pattern of the unit 1. Therefore, timing of starting of the photoelectric conversion process for taking an image of finger prints with a simple constitution unnecessary to relay on optical means to detect the presence or absence of fingers is automatically decided.

Description

TECHNICAL FIELD The present invention relates to an image input device, and more particularly to an image input device that optically detects a pattern to be verified, such as a fingerprint, and generates an electrical signal.

Conventional technology There is a system that uses fingerprints to identify individuals.C has extremely high reliability due to the characteristics of fingerprints, which are ``unique for all people'' and ``unchangeable throughout life.'' Various devices have been proposed that perform identity verification with fingerprints registered in advance.

In such a fingerprint verification device, a finger placed on the finger device surface of a glass prism is connected to a light source and an imaging device such as a 1'TV by utilizing the change in the optical boundary of the glass from the back surface of this placement surface. It has a fingerprint input device that generates a photoelectrically converted image of a fingerprint pattern using, for example, Japanese Patent Application Laid-Open No. 1983-6930.
0 and the same <'54-85600 publication.

In such a V4M, it is possible to start photoelectric conversion processing for collecting a fingerprint image by detecting the presence or absence of a finger on a prism using a photodiode or the like installed in the device, which is easily accomplished by those skilled in the art. However, there was a drawback that the equipment and control were complicated.

Purpose of the Invention The present invention has been made to eliminate such drawbacks of the conventional technology, and its purpose is to automatically use the start timing of photoelectric conversion processing for image acquisition for later verification processing. It is an object of the present invention to provide an image human power Ml that is determined based on a fingerprint image and eliminates the complexity of the device and its control.

Structure of the Invention An image input device according to the present invention is provided by placing an object to be inspected having a striped pattern to be checked on a placement surface of a transparent body, and viewing this placement surface from the opposite side of the object to be inspected. An image input device for detecting a striped pattern to be collated using the reflected light from the mounting surface, the image input device detecting a striped pattern to be collated using the reflected light from the mounting surface, wherein The present invention is characterized in that the striped pattern sampling process is started in accordance with the level of an image signal in the image scanning direction with respect to the stripes.

K-wao 1 The present invention will be explained in detail below using the drawings.

FIG. 1 is a schematic block diagram of a fingerprint matching device to which an embodiment of the present invention is applied, in which an image pattern of a fingerprint pattern obtained by a fingerprint input unit 1 is photoelectrically converted. A/
The signal is supplied to a D (analog/digital) converter 3 and becomes a digital signal. This digital signal is stored in the image memory 4.
It is temporarily stored in . On the other hand, a personal identification number (ID number) input from the keyboard 6 is supplied to the verification processor 5, and this processor accesses the file 7 using the ID number. The file 7 had stored in advance the fingerprint characteristic information of each person, so the fingerprint characteristic information according to the ID number from the professional was selectively recalled and stored in the image memory 4. A feature comparison is made with the fingerprint pattern information.

The above-mentioned prism constituting the input section @1 in the apparatus shown in FIG. 1 is shown in FIG. It is placed and crimped. Detection incident light 10 is irradiated from the opposite side of this mounting surface 81 from the finger, and reflected light 11 due to an optical boundary change occurring on this surface 81 is scanned with an ITV camera (not shown) and imaged. It is used as an electrical signal.

In this case, it is the input timing processing circuit 2 shown in FIG. 1 that determines the start timing of the scanning for fingerprint image collection, and as shown in FIG. 2(B), the resulting striped pattern 12 is The scanning line 13 is always scanned at approximately the center. The signal obtained by this scanning line 13 is constantly monitored, and when the average value of the gray level of this signal exceeds a predetermined value, it is determined that the finger 9, which is the object to be inspected, has been placed, and the entire A command signal for starting a scan is sent to the input device 1.

Upon receiving this signal, the input device 1 starts scanning the entire fingerprint pattern in order to start photoelectric conversion processing of the entire fingerprint pattern. All the fingerprint patterns scanned here are used in the subsequent verification process.

As another example, this pulse can be generated by utilizing the fact that the image signal obtained by scanning the scanning line 13 is a high-level pulse signal in the case of stripes, and a low-level signal between the stripes. The number may be counted digitally, and the start command signal may be generated when the counted value reaches a predetermined value. In addition, the entire pattern surface is scanned at all times, and only the scanning line 13 in the approximate center of FIG. It's okay.

In the above example, the object to be inspected is a fingerprint of a human finger, but it may also be a TP film (plastic thin film) on which a fingerprint pattern or any other desired pattern to be inspected is printed.

When the scan start command signal is generated in this way and the collection of the entire pattern is started, the start can be notified to the user in an auditory or visual manner. Further, even after the input is completed, the entry timing processing circuit 2 may similarly notify the user of the completion of the input.

The present invention applies to digital/analog painting and digital/analog painting.
Valid for analog memory, digital images,
When involved in digital memory, the positions of input timing processing circuit 2 and A/D conversion circuit 3 are reversed in the schematic block diagram of FIG.

Effects of the Invention According to the present invention, since the input start timing of the object to be inspected is automatically determined, there is an advantage that the user only needs to place the object to be inspected, such as a finger.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of an apparatus to which an embodiment of the present invention is applied, and FIG. 2 is a diagram illustrating the present invention in detail. Explanation of symbols of main parts 1... Input device 2... Panono timing processing circuit 8...
・Prism 9...Finger 12...Image pattern 13...Scanning line

Claims (1)

[Scope of Claims] (1) An object to be inspected having a striped pattern to be checked is placed on a placement surface of a transparent body, and light is applied to this placement surface from the opposite side of the object to be inspected. An image input device for detecting a striped pattern to be collated using the reflected light from the mounting surface, the image input device detecting the striped pattern to be matched using the reflected light from the mounting surface, the image input device An image input device characterized in that the striped pattern sampling process is started in accordance with the gray level of an image signal in an image scanning direction. (2) The image input device according to claim 1, wherein the sampling process is started in accordance with an average value of the gray level of the image signal. (3) The image input device according to claim 1, wherein pulse signals corresponding to the stripes of the image signal are counted, and the sampling process is started in accordance with this count value.