JP2589897B2 - Image reading device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for easily correcting image blur caused by floating of a document reading surface in an image reading apparatus, particularly a book type image reading apparatus.

[0002]

2. Description of the Related Art Image reading apparatuses have been widely used in copiers, facsimile machines and the like for some time. Recently, however, in facsimile machines and the like, an original is placed on a glass plate and the original is read. Book-type image reading apparatuses have been adopted. In such a conventional image reading apparatus, the reading surface of the document may sometimes rise. Therefore, in order to prevent blurring of the read image due to such a phenomenon in advance, the depth of focus of an optical lens used as a light source is made deeper than that of a normal image reading apparatus.

[0003]

However, in such a conventional image reading apparatus, the depth of focus of the optical lens is increased in order to cope with the rising of the reading surface of the document. Since both the depth of focus of the optical lens and the light amount of the light source are fixed at fixed values, it is not possible to cope with a large floating of the document reading surface, or the document is illuminated with an unnecessarily bright light amount, thereby increasing waste. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an image reading apparatus capable of correcting a blur of a read image caused by a rising of a reading surface of a document by a simple method. It is.

[0005]

The present invention achieves the above object.
To the image reading device,
Document source that has a light source member that irradiates light and an optical lens
An image reading unit that inputs reflected light from the surface and a light source member
Distance detection means for detecting the distance to the document reading surface.
The distance detecting means includes a light emitting element and a plurality of light receiving elements corresponding to the light emitting element.
It consists of an optical element. Also, the original is read from the light source member.
The focal length is adjusted according to the distance to the surface,
The data is corrected according to the brightness of the pixel of interest.
It is something.

Further, the present invention is characterized in that the image reading apparatus is provided with a means for adjusting the focusing of the optical lens based on the detection result of the distance detecting means.

[0007]

In the image reading operation, the distance detecting means operates at the time of operation of the reading unit to detect the lifting of the document. When the lifting of the document is detected, the focusing adjustment means operates to adjust the focusing of the optical lens. Focusing adjustment methods include a case where the optical lens is focused by a lens driving member,
There are cases where the depth of the subject is increased by adjusting the degree of stopping down the optical lens by the lens stop member. When the focusing is adjusted by the lens aperture member, the light source member is interlocked with the lens aperture member in order to compensate for the light amount shortage caused by the aperture stop of the optical lens, and the output of the light source member is increased when the optical lens is apertured down. Further, the frequency of the fluorescent lamp constituting the light source member is converted by the frequency control unit, and the output of the light source member is easily changed to become bright.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the image reading apparatus according to the present invention will be described below. FIG. 1 shows an embodiment of the present invention. In this figure, reference numeral 1 denotes an original, and 2 denotes an original by scanning.
Scanning unit for reading a document, 3 is a document 1
4 is a reading surface for reading the original 1, 5 is a reading unit for reading the original 1 while moving in the direction of the arrow S in the figure, and 6 is attached to the reading unit 5 and reads the reading unit 5 and the original. This is a distance detection sensor that detects the distance to the surface 4.

As shown in FIG. 2, the reading section 5 includes a fluorescent lamp 7 as a light source member for irradiating the original 1 with light, an optical lens 8 for receiving light reflected from the original reading surface 4, and an optical lens 8 Adjusting the focusing of the optical lens 8
Lens driving unit 9 that performs focusing adjustment of CCD, and CCD image sensor 1 that detects light passing through optical lens 8
0 and a fluorescent lamp driving unit 11 that adjusts the brightness of the fluorescent lamp 7 by changing the frequency applied to the fluorescent lamp 7. As the fluorescent lamp 7, for example, an inverter system that can adjust the brightness steplessly by a frequency change is used. The fluorescent lamp driving unit 11 includes a lighting signal a and a full lighting signal as shown in FIG. b is input. Further, the lens driving section 9 is connected to the distance detection sensor 6, and a detection output of the distance detection sensor 6 is input.

FIG. 4 shows an example of the configuration of the distance detection sensor 6. The distance detection sensor 6 is connected to the document reading surface 4.
Light-emitting element 12 that emits light toward the device, and light-receiving elements 13a and 13 that receive reflected light of light emitted from light-emitting element 12.
b, 13c. Light receiving elements 13a to 13c
Are arranged in a line in the order of 13a, 13b, and 13c from the side closer to the light emitting element 12 along the path where the light emitted from the light emitting element 12 is reflected by the document reading surface 4.

The operation of the image reading apparatus having such a configuration will be described below. First, for the initial startup of the image reading apparatus, when the power switch is turned on, power is supplied to each functional part, and the apparatus itself performs a warm-up operation. At this time, the lighting signal a is input to the fluorescent lamp driving unit 11, and a relatively small frequency is applied to the fluorescent lamp 7. Then, the fluorescent lamp 7 is turned on with less brightness than when fully turned on, and warms the fluorescent lamp 7 itself, the heater, and the like. As a result, it is possible to save energy and extend the life of the fluorescent lamp 7.

Next, when reading an original, as shown in FIG. 1, when an original 1 such as a book is placed on a transparent glass 3 and an image is read, a binding stitch of the original 1 rises. A contact portion 4a and a non-contact portion 4b are formed on the document reading surface 4. When the operator presses the facsimile transmission button in this state, the reading unit 5 moves in the direction of arrow S by the reading operation, the fluorescent lamp 7 is turned on, and the distance detection sensor 6 is connected to the reading unit 5, especially the optical lens 8 and the document. The distance from the reading surface 4 is detected.

The lighting operation of the fluorescent lamp 7 is controlled by the fluorescent lamp driving unit 11, and this lighting operation is shown in FIG. That is, when the facsimile transmission button is pressed,
First, a lighting signal a is input to the fluorescent lamp driving unit 11, and based on this, a high frequency signal of a certain percentage (for example, 50%) with respect to full lighting is output from the fluorescent lamp driving unit 11 to the fluorescent lamp 7. You. As a result, the fluorescent lamp 7 is turned on in a dimly lit state to warm the fluorescent lamp 7 itself or to raise the temperature of the heater. Thereafter, when it is time to actually read the original, the full lighting signal b is input to the fluorescent lamp driving unit 11. Based on this, a 100% high frequency signal corresponding to full lighting is output from the fluorescent lamp driving unit 11 to the fluorescent lamp 7, and the fluorescent lamp 7 is fully lit with the light amount increased.

On the other hand, in the distance detecting sensor 6, light is incident on the original reading surface 4 from the light emitting element 12, and the reflected light is received by the light receiving elements 13a, 13b, 13c. This distance detecting operation is shown in FIG. That is, when the incident light is incident on the contact portion 4a of the document reading surface 4, the reflected light reaches the light receiving element 13b, and when the incident light is incident on the non-contact portion 4b of the document reading surface 4, the reflected light is Light receiving element 13
reaches c. Therefore, the light receiving elements 13a, 13b, 1
The output of the light receiving element 3c is monitored, and when the output of the light receiving element 13b is large, it is judged that the document 1 is not lifted up and it is normal and normal reading is performed. When the output of the light receiving element 13c is large, the document 1 is lifted up. And make a correction.

When the document reading surface 4 is lifted,
The output of the distance detection sensor 6 is sent to the lens drive unit 9,
The lens driving unit 9 adjusts the focus of the optical lens 8. As a result, focusing adjustment is performed on the raised portion of the document reading surface 4, and a sharp read image is obtained. As shown in FIG. 6, the correction of the lifting of the document reading surface 4 is determined in advance as normal when the reflected light is received by the light receiving element 13b and correction is required when the reflected light is received by the light receiving element 13c. The correction may be performed uniformly by the correction amount, or the original reading surface 4 may be densely arranged with a large number of light receiving elements and the position of the light receiving element receiving the reflected light.
May be calculated, and a precise focusing adjustment may be performed in accordance with the calculated amount.

FIG. 7 is a diagram showing a second embodiment of the image reading apparatus according to the present invention. This embodiment has a configuration basically similar to that of the first embodiment. However, different from the first embodiment, the lens aperture member 14 is used as a means for adjusting the focusing of the optical lens 8. That is, the focusing adjustment of the optical lens 8 is
This is realized by increasing the depth of the subject by narrowing the aperture member. The output of the distance detecting sensor 6 is connected to both the lens aperture member 14 and the fluorescent lamp driving unit 11.

Therefore, according to this embodiment, when the document reading surface 4 is lifted, the distance detection sensor 6
Is output to the lens aperture member 14, which is stopped down to increase the depth of field of the optical lens 8. As a result, focusing adjustment is performed on the raised portion of the document reading surface 4, and a sharp read image is obtained. On the other hand, in this embodiment, when the lens aperture member 14 is stopped down as described above, the amount of light incident on the optical lens 8 decreases, and there is a possibility that sufficient image reading cannot be performed. In order to solve this, a drive signal c is output from the distance detection sensor 6 to the fluorescent lamp driving unit 11, and the driving signal c causes the fluorescent lamp driving unit 11 to increase power by about 120%, which is higher than full lighting. The frequency signal is output to the fluorescent lamp 7, and the fluorescent lamp 7 further increases in light amount and is overlit. Thereby, the lens aperture member 14
The decrease in light amount due to the aperture stop is covered, and a bright image can be obtained. 8 and 9 are diagrams showing still another embodiment of the correction of the lifting of the document reading surface 4 according to the present invention. In this embodiment, the floating correction of the document reading surface 4 is realized by image processing. That is, as shown in FIG. 8, the image reading apparatus according to this embodiment includes, as focusing adjustment means, a focusing adjustment member 15 such as the lens driving unit 9 or the lens aperture member 14 in the previous embodiment. A pixel detection member 16 for detecting a change in brightness of a pixel of interest before and after the focusing operation of the focusing adjustment member, and a data correction member 17 for correcting image data of the pixel of interest based on a detection result of the pixel detection means. And a control unit 18 for controlling the operations of the pixel detection member 16 and the data correction member 17. Other configurations are the first,
This is the same as the second embodiment.

In the operation of this embodiment, when the document reading surface 4 is lifted, the distance detection sensor 6
Output from the focusing adjustment member 15 and the control unit 18
Sent to When the focusing adjustment member 15 is constituted by a lens aperture member, the distance detection sensor 6
Is also sent to the fluorescent lamp driving unit 11. Upon receiving the detection result of the distance detection sensor 6, the control unit 18 causes the CCD image sensor 10 to perform the first-stage image reading before the focusing adjustment operation is performed by the focusing adjustment member 15, and FIG. The normal CCD analog output shown in FIG. FIG. 9 shows each dot 19
a, 19b, 19c, 19d... 19n indicate image data, in which squares represent dots, and dots at the same position in the vertical direction between (a) to (c) are the same. Represents a dot. Next, the control unit 18 causes the focusing adjustment member 15 to perform the focusing adjustment operation based on the detection result of the distance detection sensor 6, and in the state after the focusing adjustment, causes the CCD image sensor 10 to read the second-stage image. Then, the blur-corrected CCD analog output shown in FIG. 9B is obtained. Then, the control unit 18 causes the pixel detection member 16 to pay attention to each dot from the normal CCD analog output and the blur correction CCD analog output, and to detect a change in brightness of the pixel of interest before and after the focusing operation of the focusing adjustment member 15. Let it be detected. That is, as shown in FIG. 9, for example, the brightness of the dot 19b before the focusing adjustment is 50%, but the brightness after the focusing adjustment is 20%, and the pixel detection member 16 has the dot 19n.
With respect to (3), a change such that the brightness before the focusing adjustment is 30% but becomes 80% after the focusing adjustment is detected, and the detection result is output to the data correction member 17. Data correction member 17
When the detection result of the pixel detection member 16 is received, data correction is performed according to a predetermined algorithm, and
Generate a D analog output. That is, in the data correction member 17, since the brightness of the dot 19b was initially 50%, but the brightness was reduced to 20% after the focusing adjustment, the dot 19b had no data from the beginning. Is determined,
0% is used for the blur correction CCD analog output.
On the other hand, as for the dot 19n, the brightness was initially reduced to 80% when the focusing adjustment was performed, but the brightness was reduced to 80%. Therefore, it was determined that the dot 19n had 100% data from the beginning. 100% is used for the blur correction CCD analog output. Further, since the brightness of the dots 19c and 19d does not change to 50% before and after the focusing adjustment, the blur correction CCD analog output of 50% is directly generated for these dots. As described above, after the floating of the document reading surface 4 is detected, the focusing is adjusted, and further image processing is performed, whereby the blur of the read image data due to the floating of the document reading surface 4 can be corrected with high accuracy.

[0019]

As described above, according to the present invention,
The lifting of the document reading surface is determined by the light emitting element and the corresponding
Number of light-receiving elements, and
Distance is determined, so the distance can be determined instantaneously.
Quickly rises from the light source to the document reading surface
Rig can be detected. In addition, the detected distance
By controlling the frequency of the fluorescent light according to
Such a thing disappears. Also, according to the detected distance
Adjust the degree by narrowing down the optical lens
Therefore, even if the document surface rises, defocusing will not occur.
And a high quality read image can be obtained. In addition, the optical lens
Frequency of the light source output in conjunction with
With this, you can control the output of the light source according to the focus.
As a result, a high-quality read image can be obtained. Also, the image reading operation
Sometimes the light intensity of the light source member is fine between half lighting and full lighting.
Energy can be adjusted to save energy
And various effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an image reading apparatus according to the present invention.

FIG. 2 is a block diagram showing a first embodiment of a reading unit in the image reading apparatus.

FIG. 3 is a block diagram showing a fluorescent lamp used in the embodiment and a driving mechanism thereof.

FIG. 4 is a diagram showing a configuration example of a distance detection sensor used in the embodiment.

5 is a signal waveform diagram for explaining the operation of the fluorescent lamp and its driving mechanism shown in FIG.

FIG. 6 is a view for explaining the operation of the distance detection sensor shown in FIG. 4;

FIG. 7 is a block diagram showing a second embodiment of a reading unit in the image reading apparatus of the present invention.

FIG. 8 is a block diagram showing a third embodiment of a reading unit in the image reading apparatus of the present invention.

FIG. 9 is a view for explaining an image processing operation in the third embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 document 2 plane scanning unit 3 transparent glass 4 document reading surface 5 reading unit 6 distance detection sensor 7 fluorescent lamp (light source member) 8 lens 9 lens driving unit 10 CCD image sensor 11 fluorescent lamp driving unit 12 light emitting element 13 light receiving element 14 lens Aperture member 15 Focusing adjustment member 16 Pixel detection member 17 Data correction member 18 Control unit

Claims (5)

(57) [Claims] A light source member for irradiating light to a reading surface of a document; an image reading unit having an optical lens for inputting reflected light from the document reading surface; and emitting light to the document reading surface.
A light-emitting element, and light received from the light-emitting element.
To the proper position and the proper position
Light-receiving elements arranged before and after a light-emitting element
And a light source member according to the output results of the plurality of light receiving elements.
An image reading apparatus comprising: a distance detecting unit that determines a distance from a document to a document reading surface . 2. The light source member has a brightness by frequency conversion.
And the frequency applied to this fluorescent lamp
And a frequency control unit for controlling the distance detection.
Frequency of the frequency control unit according to the distance detected by the output means.
2. The image reading apparatus according to claim 1, wherein the number is controlled.
apparatus. 3. A light source for irradiating light to a reading surface of a document
Member and an optical lens to receive reflected light from the original reading surface.
And the distance from the light source member to the document reading surface.
Distance detecting means for detecting separation and detection of the distance detecting means
Adjust the aperture of the optical lens based on the result
An image reading device comprising a lens aperture member. 4. A light source member in conjunction with the lens stop member.
Light source member driving means for varying the frequency of the output
The image reading apparatus according to claim 3, wherein: 5. A light source for irradiating light to a reading surface of a document
Member and an optical lens to receive reflected light from the original reading surface.
And the distance from the light source member to the document reading surface.
Distance detecting means for detecting separation and detection of the distance detecting means
Move the optical lens in at least two stages based on the results.
Focus adjustment before and after the focusing operation
Changes in the brightness of the pixel of interest in the
A file for correcting the image data of the pixel of interest based on the result.
An image reading device comprising focusing adjustment means.