JPH0365778A - Picture input device - Google Patents

Abstract

PURPOSE:To obtain a sharp picture, for which distortion is reduced, by fixing a one-dimensional image sensor and a lighting means to the inner wall surface of a transparent body so as to satisfy a total reflection condition and executing sub scanning along the outer wall surface of the transparent body while keeping the total reflection condition. CONSTITUTION:A transparent body 1-1 is equipped with a transparent elastic body thin film 1-7 on the inner wall surface and a one-dimensional image sensor 1-2 is fixed to focus the inner wall surface and controlled to execute main scanning. Then, these transparent body 1-1 and one-dimensional image sensor 1-2 are fixed to the inner wall surface so as to satisfy the total reflection condition and with the fixed one-dimensional sensor 1-2 and the lighting means 1-2, the sub scanning is executed by a sub scanning means 1-4 along the outer wall surface of the transparent body 1-1 while keeping the total reflection condition. Thus, the picture can be widely obtained without trapezoidal distortion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an image-powered device, and more particularly to an image-powered device that optically detects a stamp to be verified, such as a fingerprint, and converts it into an electrical signal.

[Prior Art] Conventionally, as this type of image input device, the device shown in FIG. 4 is known.

In FIG. 4, 40 is a prism, and the prism 40
The − plane is illuminated by the light source 41.

The light from the light source 41 is totally reflected by the surface A-A' of the prism 40 and input to the detector 42 . At plane AA' of prism 40 as shown in FIG.

At the portion where the fingerprint pattern of the finger 1-10 touches the prism 40, conditions for total reflection are disrupted due to sweat secreted from the skin and moisture on the fingerprint pattern, causing diffuse reflection of the light from the light source 41. On the other hand, the total internal reflection condition does not collapse in areas where the fingerprint pattern does not touch. Therefore, the detector 42 is a fingerprint pattern prism 4.
The difference in the amount of reflected light between the part touching 0 and the part not touching can be detected as a grayscale fingerprint image.

The analog image signal output from the detector 42 is quantized by the A/D conversion circuit 43 and input to the storage circuit 44, where it is stored. Here, the A/D conversion circuit 43
The start of conversion and writing to the memory circuit 44 are performed by an operator who judges the quality of the image by himself while looking at the monitor 45.
By inputting an input start signal from the keyboard 46.

From the control circuit 47 to the A/D conversion block and the memory circuit 4
An order is issued to 4. Further, the fingerprint image stored in the storage circuit 44 is manually input to a host computer (not shown) via an interface 48. Such devices are disclosed, for example, in Japanese Patent Application Laid-open No. 54-89300 and Japanese Patent Application Laid-Open No. 54-8
It is disclosed in Japanese Patent No. 5800.

[Problems to be Solved by the Invention] Since the above-described conventional image-powered device uses a prism, the stamping surface on which the finger is placed is a flat surface. Therefore, there is a problem in that the input image is a flat stamped image and only a fingerprint image containing one trapezoidal distortion can be input.

Also, since the printing surface is glass, your fingers may be dry.

With rough fingers, there is a problem in that sufficient adhesion between the ridges and the glass surface cannot be obtained, and clear gradation images cannot be obtained.

An object of the present invention is to provide an image input device that can obtain clear images with little distortion.

[Means for Solving the Problems] The present invention provides a transparent body having an inner wall surface and an outer wall surface having concentric cylindrical surfaces, and having a transparent elastic thin film on the inner wall surface.

a one-dimensional image sensor whose focal point is fixed to the inner wall surface and controlled to perform main scanning; and illumination means for illuminating an imaging area of the one-dimensional image sensor, the one-dimensional image sensor and the illumination means is fixed to the inner wall surface of the transparent body so as to satisfy the total reflection condition, and the fixed one-dimensional image sensor and the illumination means are fixed to the outer wall surface of the transparent body while maintaining the total reflection condition. The present invention is characterized in that it includes a sub-scanning means that performs sub-scanning along the line.

[Example] Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a perspective view showing the structure of an embodiment of the fingerprint detection section of the human-powered image device of the present invention. 1-1 is a transparent body whose inner wall surface is coated with a transparent elastic thin film.

1-2 is a line sensor, 1-3 is a light source, 1-4 is a pulse motor, 1-5 is a support stand, 1-6 is an optical fiber lens, and 1-10 is a finger.

The transparent body 1-1 is made of a transparent material such as glass.

It has a semi-cylindrical shape, like a cylinder divided into two along its axis. This semi-cylindrical transparent body 1-1 has a radius on its inner wall surface that is large enough to allow contact with the distal phalanx of the fingertip. Light source 1-3 and line sensor 1-2
is fixed to a common support base 1-5, and the transparent body 1-
1 along the axial direction. An optical fiber lens 1-6 is mounted on the transparent body 1-2 on this line sensor 1-2.
1 and fixed at a predetermined interval.

Here, what is the light source 1-3 and the line sensor 1-2?

In the enlarged partial sectional view of FIG. 2, they are arranged in a positional relationship that satisfies the conditions for total reflection.

As shown in FIG. 1, the support stand 1-5 fixes the light source 1-3 and the line sensor 1-2 at its tip, and is fixed to the rotating shaft of the pulse motor 1-4 at its base. . The rotation axis of this pulse motor 1-4 is arranged to coincide with the central axis of a virtual cylindrical body including the transparent body 1-1. Therefore, as the pulse motor 1-4 rotates, the light source 1-3 and line sensor 1-2 move around the outer wall surface of the transparent body 1-1 along the outer wall surface while keeping their mutual positional relationship unchanged. Moving.

FIG. 3 shows a block diagram of an embodiment of the present invention.

At the time of fingerprint input, the line sensor 1-2 controlled by the sensor drive circuit 33 is in a stopped state. After placing the finger 1-10 on the inner wall surface of the transparent body 1-1, the operator inputs a scan start signal to the control circuit 32 from the host computer (not shown) via the interface 37. Control circuit 3
2 sends a scan start signal to the sensor drive circuit 33, and outputs a control signal necessary for main scanning of the line sensor 1-2. Further, when the scanning start signal is input manually, the mechanical drive circuit 34 sends a drive pulse to the pulse motor 1 - 4 to execute sub-scanning of the fingerprint detection section 31 . The image signal captured by this operation is quantized by the A/D conversion circuit 35,
Thereafter, it is stored in the storage circuit 36. The image data stored in the storage circuit 36 is sent to a host computer (not shown) via an interface 37.

Although a curved glass body is used in one or more embodiments, it is also possible to use a synthetic resin such as transparent plastic.

Furthermore, a known method for coating the transparent elastic body is used, and its description will be omitted here.

[Effects of the Invention] As explained above, the present invention uses a transparent body having a concentric cylindrical inner wall surface and an outer wall surface for the fingerprint stamping part, so that the input image area is wider than when using a prism, and trapezoidal distortion is avoided. A fingerprint image with no blemishes can be obtained.

Furthermore, by applying a transparent elastic thin film to the wall surface of the transparent body, high adhesion between the fingerprint pattern and the imprinting surface can be obtained, so that a clearer gradation image can be obtained compared to a transparent body alone.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the fingerprint detection section of the human-powered image device of the present invention, FIG. 2 is a partially enlarged sectional view of the fingerprint detection section of FIG. 1, and FIG. 3 is an embodiment of the present invention. 4 is a block diagram of a conventional image input device, and FIG. 5 is a diagram for explaining the principle of fingerprint detection. 1-1... Transparent body, 1-2... Line sensor, 1-
3...Light m, 1-4...Pulse motor, 1-5...
・Support stand, 1-6...Optical fiber lens, 1-7・
. . . Transparent elastic thin film, 1-10 . . . Finger, 31 . . . Fingerprint detection unit. 32... Control circuit, 33... Sensor drive circuit, 34
... Mechanical drive circuit, 40... Prism, 41...
light source. 42... Detection unit, 43... A/D conversion circuit, 44.
...Memory circuit, 45...Monitor, 46...Keyboard, 47...Control circuit, 48...Interface. Figure 1

Claims (1)

[Claims] 1. A transparent body having an inner wall surface and an outer wall surface of concentric cylindrical surfaces and a transparent elastic thin film on the inner wall surface, and a one-dimensional image that is controlled to perform main scanning with a focus fixed on the inner wall surface. A sensor, and an illumination means for illuminating an imaging area of the one-dimensional image sensor, and the one-dimensional image sensor and the illumination means are fixed to an inner wall surface of the transparent body so as to satisfy a total reflection condition. An image input device comprising: sub-scanning means for sub-scanning the fixed one-dimensional image sensor and illumination means along the outer wall surface of the transparent body while maintaining the total reflection condition.