JPH1070635A - Image reading method and image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately read an image without causing a direction characteristic even when there is any unevenness on the surface of an original. SOLUTION: A light source 21 produces a lighting light P. A half mirror 23 emits the lighting light P in a direction orthogonal to the surface of an original 10 and transmits through a reflected light reflected in the surface. A light receiving element 25 receives a reflected light Q reflected in a direction orthogonal to the surface of the original 10 among reflected lights via a lens 24, converts the light into an electric signal, from which an image of the surface is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading method and an image reading apparatus for reading a printed matter, a credit card, and the like, and more particularly, to an image reading method and an image for reading an image on the surface of a document using a contact image sensor. It relates to a reading device.

[0002]

2. Description of the Related Art A conventional image reading apparatus is described in, for example, page 12 of "Important Technology of Image Scanner and Application System for New Product Development, Published by Technical Information Association, August 15, 1988, First Edition". It was disclosed in the lower row. As shown in FIG. 5, in the conventional image reading apparatus,
The reading unit 40 includes the light source 21, the lens 24, the light receiving element 2
5 is provided.

[0005] The light source 21 generates illumination light P and irradiates the surface of the document 10. The light receiving element 25 receives the reflected light Q reflected from the surface of the document 10 via the lens 24, converts it into an electric signal, and obtains an image of one line in the main scanning direction of the document. Then, by moving the document 10 or the reading unit 40 in the sub-scanning direction, the surface of the document 10 can be scanned to read an image on the entire surface of the document 10.

The document 10 is a flat paper such as a book or a printed matter, or an object having an uneven surface such as a credit card.

[0005]

In the above-described conventional image reading apparatus, the illumination light P from the light source 21 is obliquely incident on the surface of the document 10, and as shown in FIG.
If the surface has irregularities 11, a shadow S is generated, which makes it difficult to read an image. In addition, when the document is scanned in a different direction, since the shadow always occurs in the same direction, the obtained image is different, and there is a problem in that the image is read in a direction.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading method and an image reading apparatus capable of reading an image on the surface of a document accurately and without any directionality even if the surface has irregularities. To provide.

[0007]

In order to achieve the above object, the present invention provides an image reading apparatus that irradiates a surface of a document to be illuminated with illumination light and forms an image of the reflected light reflected from the surface. In the image reading method for reading an image of the surface, the illuminating light is irradiated in a direction perpendicular to the surface, and reflected light reflected in a direction perpendicular to the surface is imaged. To provide an image reading method.

In the above image reading method, the illuminating light is perpendicularly incident on the surface of the original and forms an image of the reflected light which is reflected perpendicularly to the surface. Also, no shadow due to the unevenness occurs. For this reason,
The image on the front side of the document can be read accurately, and the same image can always be obtained regardless of the orientation of the document.

According to another aspect of the present invention, there is provided a light source for generating illumination light, comprising: a light source for reflecting the illumination light to guide the illumination light in a direction perpendicular to a surface of a document to be read; An image reading device, comprising: a half mirror that transmits reflected light reflected from a light source; and a light receiving element that receives, via a lens, reflected light reflected in a direction perpendicular to the surface. I do.

In the image reading apparatus according to the second aspect,
The half mirror irradiates the illumination light from the light source perpendicularly to the surface of the document, and the light receiving element receives the reflected light reflected perpendicularly to the surface. Shadows due to unevenness do not occur. For this reason, the image on the front surface of the document can be accurately read, and the same image can always be obtained regardless of the orientation of the document.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited by this. -First Embodiment- FIG. 1 is an explanatory diagram showing a first embodiment of the image reading apparatus of the present invention.

In this image reading apparatus, the reading section 20 includes a light source 21, a half mirror 23, a lens 24, and a light receiving element 25. The reading unit 20
Is set to a non-reflective state, for example, black. The light source 21 generates the illumination light P. The half mirror 23 reflects the illumination light P and orthogonally crosses the surface of the document 10 to be read (incident angle = 0 °).
Irradiation. At this time, a part of the illumination light P passes through the half mirror 23 and becomes extra light, but the extra light is absorbed because the inside of the reading unit 20 is black.

The half mirror 23 transmits the light reflected from the surface of the document 10. At this time, a part of the reflected light is reflected by the half mirror 23 and becomes extra light, but since the inside of the reading unit 20 is black, the extra light is absorbed. The document 10 is an object having an uneven surface such as a flat paper such as a book or a printed matter or a credit card.

The light receiving element 25 is provided for the original 10 in the reflected light.
The reflected light Q reflected in a direction (reflection angle = 0 °) perpendicular to the surface of the original 10 is received via the lens 24, converted into an electric signal, and an image of one line of the original 10 in the main scanning direction is formed. obtain. The lens 24 is, for example, a rod lens, and the light receiving element 25 is, for example, an α-Si contact sensor or a CCD contact image sensor.

Next, the surface of the original 10 is scanned while moving the original 10 or the reading unit 20 in the sub-scanning direction, and the original 10 is scanned.
Read the image of the entire surface of. Note that the illumination light P is
Irradiation is performed in a direction perpendicular to the surface of the document 10 (incident angle = 0 °), so that even if the surface of the document 10 has irregularities 11, no shadow due to the irregularities 11 occurs.

Since the light receiving element 25 receives the reflected light Q reflected in a direction orthogonal to the surface of the document 10, even if the surface of the document 10 has
1 does not interfere with the reflected light Q. FIG. 2 is an explanatory diagram showing a modification of the first embodiment of the image reading apparatus of the present invention.

Also in this image reading apparatus, the light source 21 of the reading section 20 generates the illumination light P and is orthogonal to the surface of the original 10 to be read (incident angle = 0 °).
Irradiation. The inside of the reading unit 20 is in a non-reflection state, and is, for example, black. The half mirror 23 transmits the illumination light P. At this time, a part of the illumination light P is reflected by the half mirror 23 and becomes extra light, but since the inside of the reading unit 20 is black, the extra light is absorbed.

The half mirror 23 further reflects light reflected from the surface of the document 10. At this time, part of the reflected light passes through the half mirror 23 and becomes extra light, but the extra light is absorbed because the inside of the reading unit 20 is black. The light receiving element 25 receives, via the lens 24, the reflected light Q reflected at right angles (reflection angle = 0 °) to the surface of the document 10 in the reflected light, converts the reflected light Q into an electric signal, and An image for one line in the main scanning direction is obtained.

Next, the surface of the original 10 is scanned while moving the original 10 or the reading section 20 in the sub-scanning direction, and the original 10 is scanned.
Read the image of the entire surface of. Note that the illumination light P is
Irradiation is performed in a direction perpendicular to the surface of the document 10 (incident angle = 0 °), so that even if the surface of the document 10 has irregularities 11, no shadow due to the irregularities 11 occurs.

Since the light receiving element 25 receives the reflected light Q reflected in a direction perpendicular to the surface of the document 10, even if the surface of the document 10 has
1 does not interfere with the reflected light Q. According to the image reading apparatus of the first embodiment, the half mirror 23 is
Is incident on the surface of the document 10 in a direction perpendicular to the surface of the document 10, and the light receiving element 25 receives the reflected light Q reflected in the direction perpendicular to the surface of the document 10. Even if there is, no shadow due to the unevenness 11 is generated. Therefore, the surface of the document 10 can be accurately read, and the same image can always be obtained regardless of the orientation of the document 10. -Second Embodiment- FIG. 3 is an explanatory diagram showing a second embodiment of the image reading apparatus of the present invention.

In this image reading apparatus, the reading section 30 includes a light source 21, a mirror 22, a half mirror 23, a lens 24, and a light receiving element 25. Light source 21
Generates illumination light P, and the mirror 22 reflects the illumination light P and guides it to the half mirror 23. Other operations are the same as those of the image reading apparatus of FIG. By arranging the components of the reading unit 30 as shown in FIG.
Can be reduced in size. In other words, if the size of the reading unit 30 is the same, a larger (brighter) light source can be used, so that an image can be read more accurately.

FIG. 4 is an explanatory view showing a modification of the second embodiment of the image reading apparatus of the present invention. Also in this image reading apparatus, the reading unit 30 includes the light source 21, the mirror 22, the half mirror 23, the lens 24, and the light receiving element 25. The mirror 22 further reflects the light reflected from the half mirror 23, and the light receiving element 25 reflects the light reflected in a direction (reflection angle = 0 °) orthogonal to the surface of the document 10 in the reflected light. Q is received via the lens 24. Other operations are the same as the operations of the image reading apparatus in FIG.

According to the image reading apparatus of the second embodiment, since a large (bright) light source can be used, an image on the surface of a document can be read accurately.

[0024]

As described above, the present invention illuminates the surface of a document to be read with an illuminating light, and forms an image of the reflected light reflected from the surface, thereby forming an image on the surface. When reading, the illumination light is irradiated in a direction orthogonal to the surface, and the reflected light reflected in a direction orthogonal to the surface is imaged. As a result, even if there is unevenness on the surface of the document, the shadow due to the unevenness does not occur, so that the image on the surface of the document can be accurately read and the same image can always be obtained regardless of the orientation of the document. become.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of an image reading apparatus of the present invention.

FIG. 2 is an explanatory diagram showing a modification of the first embodiment of the image reading apparatus of the present invention.

FIG. 3 is an explanatory diagram showing a second embodiment of the image reading apparatus of the present invention.

FIG. 4 is an explanatory diagram showing a modification of the second embodiment of the image reading apparatus of the present invention.

FIG. 5 is an explanatory diagram of a conventional image reading apparatus.

FIG. 6 is an explanatory diagram of a shadow generated by irregularities on the surface of a document.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Original 11 Irregularities 20, 30 Reading part 21 Light source 22 Mirror 23 Half mirror 24 Lens 25 Light receiving element P Illumination light Q Reflected light

Claims (5)

[Claims] 1. An image reading method for reading an image on a surface of a document to be read by irradiating the surface of the document with illumination light and forming an image of reflected light reflected from the surface, wherein the illumination light is An image reading method, comprising irradiating light in a direction perpendicular to the surface and forming an image of reflected light reflected in a direction perpendicular to the surface. 2. A light source for generating illuminating light, and a half mirror for reflecting the illuminating light and guiding the illuminating light in a direction perpendicular to the surface of a document to be read, and transmitting the reflected light reflected from the surface. An image reading apparatus comprising: a light receiving element that receives light reflected in a direction perpendicular to the surface. 3. The image reading apparatus according to claim 2, further comprising a reflection unit that guides illumination light from the light source to the half mirror. 4. A light source that irradiates illumination light in a direction orthogonal to a surface of a document to be read, and a half mirror that transmits the illumination light and reflects light reflected from the surface. And a light receiving element for receiving, via a lens, reflected light reflected in a direction orthogonal to the surface in the reflected light from the half mirror. 5. The image reading device according to claim 4, further comprising: a reflection unit that guides, out of the light reflected from the half mirror, light reflected in a direction orthogonal to the surface to the light receiving element. An image reading apparatus, comprising: