JP2002185717A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To arrange an imaging unit so as not to obstruct the visual range of an operator to an original when the operator performs work on an original platen in a standing state. SOLUTION: A column 4 is vertically erected on the upper surface of the original platen 2, the imaging unit 3 is attached on the tilt at the upper part of the column 4 and the optical axis 5 of the imaging unit 3 is inclined to a vertical direction. At the time, the imaging unit 3 does not get in the visual range of the operator H to the original 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for optically reading an image of a document or the like from above.

[0002]

2. Description of the Related Art Conventionally, there has been known an image reading apparatus in which a document, particularly a book document such as a book, is placed upward and an image of the document is optically read. As a known image reading apparatus, there is one described in Japanese Patent Application Laid-Open No. 8-154154. In this image reading device, an image pickup device that optically reads a document image is mounted above a document table via a support. Then, the shape of the side surface of the book document and the height of the document surface are detected, and distortion of the image data is corrected based on the shape, thereby obtaining a highly accurate reproduced image.

[0003]

By the way, in the above-described image reading apparatus, as shown in FIG. 11, an image pickup device 40 is arranged above a document table 50 in order to reduce image distortion. The optical axis 60 and the document table 50 are set to be orthogonal. However, in such a structure, the lower part of the imaging device 40 obstructs the field of view of the operator H with respect to the original 70 (A in the figure), so that the original table 5
There is a problem that it is difficult to perform operations such as turning a page and positioning on 0. In addition, I in FIG. 11 indicates a portion where the field of view of the operator H is blocked by the imaging device 40.

[0004] In view of the above, it is an object of the present invention to provide an image reading apparatus capable of eliminating the blind spot of an operator and improving workability on a document table.

[0005]

In order to achieve the above object, an image reading apparatus according to the present invention has an image pickup device arranged so as not to obstruct the field of view of an operator's original, thereby improving workability on an original table. Is to improve. For this reason, the imaging device provided on the document table via the support is arranged such that the optical axis thereof is inclined backward with respect to the vertical direction. That is, the image pickup device is attached to the support at an angle so that the lower portion of the image pickup device does not obstruct the operator's view of the document. Alternatively, the struts are inclined.

As a result, even when the operator stands in front of the document table and works, the imaging device does not obstruct the field of view,
Since the entire surface of the document can be looked at while standing, it becomes easy to perform operations such as turning pages and positioning. It is assumed that the optical axis is always perpendicular to the lower surface of the imaging device. Further, the operation of the image reading device is performed in the standing posture, and the operator performs the operation at the front of the document table, that is, at the position facing the imaging device.

By the way, if the optical axis of the imaging device is inclined with respect to the vertical direction, the original image of the original placed horizontally will be distorted. In order to prevent this, the optical axis may be set to be perpendicular to the mounting surface of the document table. In other words, if the mounting surface is inclined with respect to the horizontal plane so as to be perpendicular to the optical axis, the image pickup device will be disposed substantially directly above the document, so that distortion of the document image can be prevented. it can. Therefore, the mounting surface of the document table is preferably inclined so as to be lowered toward the back side, and is preferably set at an angle perpendicular to the optical axis.

Here, when the image reading range is widened, distortion occurs at the end of the image to be read, but the "distortion" in the text is caused by the fact that the optical axis is shifted with respect to the mounting surface of the document table. It is caused by the inclination.

A reference position for positioning the document is set on the mounting surface. When the document table is inclined, the reference position is set to a lower position, and a document reference plate is disposed here. deep.
Then, when the document is positioned, it comes into contact with the document reference plate, so that the document can be prevented from slipping under its own weight, and the position of the document can be kept constant.

[0010] As another means for solving the problem, a column for supporting the imaging device may be rotatable and inclined with respect to a horizontal plane. Therefore, the support column is provided with a pivot point,
The inclination angle of the support with respect to the platen can be freely changed.

As described above, if the column is made rotatable, the imaging device can be freely tilted to an angle that does not obstruct the operator's field of view. Workability on the table can be improved.

As another mode, the document table may be rotatable with respect to a horizontal plane. Thereby, even when the imaging device is provided such that the optical axis is inclined from the vertical direction, if the angle of the original table is adjusted so that the mounting surface of the original table and the optical axis are orthogonal to each other, It is possible to prevent the original image from being distorted. Further, a mode in which both the support and the document table are rotatable can be adopted. In this case, the support and the platen can be separately set at an angle at which the operator can easily operate, so that the operability can be improved.

As described above, when adopting a configuration in which the platen is rotatable, it is preferable to provide a restricting member for restricting the platen from inclining at a predetermined angle or more. Specifically, the angle between the mounting surface on the front side of the platen and the optical axis is 9
What is necessary is just to provide a regulating member so that it may become 0 degree or more. If the angle is smaller than 90 degrees, the inclination of the document table becomes unnecessarily large, so that it is difficult for the operator to view the document on the document table, and it is also difficult to perform operations such as turning pages and positioning on the document table. Therefore, operability is impaired. But 9
By setting the angle to 0 degrees or more, this can be prevented.

Further, a mode in which the document table and the support are integrated and provided rotatably can be adopted. In this case, since the optical axis of the imaging device and the document table are always orthogonal to each other, it is possible to avoid distortion of the document image, and furthermore, it is possible to freely tilt the imaging device to an angle that is easy for the operator to operate. ,
Operability can be improved.

Here, a mode is adopted in which the optical axis of the image pickup apparatus is inclined with respect to the mounting surface of the document table, or both or both of the document table and the support are rotatable. In some cases, depending on the angle between the optical axis and the platen, the read document image may be distorted.

As a means for eliminating the distortion of the original image, the operator may adjust the angles of the original table and the optical axis so that these are always orthogonal to each other. On the other hand, a configuration in which an image processing device for correcting distortion of a read image is provided in an imaging device as software means may be employed.

That is, the image processing apparatus comprises a distortion correcting means for correcting image distortion, a first inclination detector for detecting the inclination of the optical axis, and a second inclination detector for detecting the inclination of the mounting surface. And performs an interpolation process or a thinning process of pixels of image data based on the respective inclination data obtained from the first inclination detector and the second inclination detector to correct the distortion of the original image.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing the image reading apparatus. The image reading device is the original 1
Is read optically from above, and the image is transferred to an output device such as a personal computer or a printer, and is particularly suitable for reading the original 1 in the upward facing state.

In the image reading apparatus, an image pickup device 3 for optically reading a document image is arranged above a document table 2 on which a document 1 is placed. The image pickup device 3 is attached to an upper portion of a support column 4 that stands vertically on the document table 2 so as to protrude frontward. The optical axis 5 of the imaging device 3 is inclined with respect to the support column 4 so as to approach the operator H side. That is, the imaging device 3 is in a state of being inclined with respect to the horizontal mounting surface 6. Therefore, when the operator H stands on the front side of the document table 2 and looks down on the document 1, the entire field of the document 1 can be seen without being blocked by the imaging device 3. Here, an area A surrounded by a two-dot chain line in FIG.

(Second Embodiment) FIG. 2 shows an image reading apparatus according to this embodiment. The present embodiment is characterized in that the original table 2 is inclined so that the optical axis 5 and the mounting surface 6 of the original table 2 are orthogonal to each other, and the other configuration is the same as that of the first embodiment. The mounting surface 6 is inclined downward from the front of the operator H toward the back. And the optical axis 5
The tilt angle of the mounting surface 6 is set so that the mounting surface 6 and the mounting surface 6 are perpendicular to each other, and the imaging device 3 and the mounting surface 6 are made parallel.

The column 4 is set up on the back of the platen 2, but may be set up on the side of the platen 2. That is, when the operator H operates while standing on the side of the image reading apparatus, it is better to provide the support 4 on the side of the platen 2.
The approaching side is either left or right, and depending on the person, this mode is easier to operate.

Here, a reference position for positioning the document 1 is set on the lower side of the placing surface 6. A document reference plate 7 protrudes from the reference position.
When the document is placed, the document 1 is pressed against the document reference plate 7,
Position.

Thus, when the placing surface 6 is inclined, the document 1 can be prevented from slipping down due to its own weight, and the position of the document can be kept constant. In addition, pillar 4
Even when the image pickup device 3 is attached at an angle, the optical axis 5 and the mounting surface 6 are orthogonal to each other, so that a document image without distortion can be obtained and the field of view of the document 1 is blocked by the image pickup device 3. Therefore, the work on the document table 2 is facilitated.

(Third Embodiment) FIG. 3 shows an image reading apparatus of the present embodiment. This image reading device is configured such that the imaging device 3 does not block the operator's view of the document 1.
The strut 4 supporting the imaging device 3 is inclined backward with respect to a horizontal plane. Therefore, the lower portion of the support 4 is attached to the upper surface of the document table 2 via the pivot 20.
The support column 4 is rotatable around the rotation fulcrum 20 in a direction away from the operator.
Is provided with a known locking means such as a stopper (not shown), and the column 4 is fixed at a predetermined inclination.

The image pickup device 3 is attached to the column so that the optical axis 5 is parallel to the column 4. As in the first embodiment, the image pickup device 3 is obliquely attached to the column 4. It is also possible. Other configurations are the same as those of the first embodiment.

As described above, if the column 4 is made rotatable, the operator can freely rotate the image pickup device 3 to a position where the field of view with respect to the document 2 is not obstructed. Can be adjusted, and work on the document table 2 becomes easy.

(Fourth Embodiment) In the image reading apparatus of the fourth embodiment, as shown in FIG. 4, the document table 2 is rotatable with respect to a horizontal plane. That is, the mounting plate 8 is attached to the back side of the document table 2 via the rotation fulcrum 21, and the upper surface of the mounting plate 8 serves as the mounting surface 6. The mounting plate 8 rotates about the rotation fulcrum 21 in a direction approaching from the front side. Note that the imaging device 3 is the same as in the third embodiment.

As described above, the mounting plate 8 and the support column 4 are independently rotatable, so that the imaging device 3 and the mounting plate 8 can be arbitrarily set to an angle at which the operator can easily work. Therefore, the operability of the image reading device can be improved.

A regulating member 30 for regulating the inclination angle of the mounting plate 8 is provided on the support 4 so as to protrude toward the front side. This regulating member 30 is in contact with the document reference plate 7 on the placing plate 8 as shown in FIG. At this time, since there is a gap between the regulating member 30 and the document reference plate 7, the placing plate 8 is rotatable. The mounting plate 8 is the pivot 2
4B, when the document reference plate 7 comes into close contact with the regulating member 30 as shown in FIG. 4B, the rotation of the placing plate 8 is regulated.

Thus, the mounting plate 8 can be prevented from approaching the imaging device 3 more than necessary, and the angle α between the optical axis 5 of the imaging device 3 and the front side of the mounting surface 6 can be set to 90 degrees or more. . If the angle α is smaller than 90 degrees, the inclination of the mounting plate 8 with respect to the horizontal plane becomes large, so that the original image distortion becomes large. In addition, the original 1 on the mounting plate 8 is difficult to see, and operations such as turning pages and positioning are difficult.

As described above, the original reference plate 7 and the regulating member 30
The optical axis 5 and the mounting plate 8 can be made orthogonal to each other, and if this state is maintained, distortion of the original image can be easily eliminated. In addition,
The regulating member 30 may be provided on the upper surface of the document table 2.

(Fifth Embodiment) In an image reading apparatus according to a fifth embodiment, as shown in FIG. 5, the support 4 and the mounting plate 8 are integrated, and are connected to the document table 2 via a rotation fulcrum 22. It is characterized in that it is attached, and the other configuration is the same as that of the third embodiment.

The imaging device 3 is parallel to the mounting surface 6, and the optical axis 5 is parallel to the support 4. The rotation fulcrum 22 is arranged on the back side of the document table 2, and the image pickup device 3 and the mounting plate 8 are integrally inclined backward about the rotation fulcrum 22.

The image read by the imaging device 3 is
Since the optical axis 5 and the mounting plate 8 are always orthogonal to each other, an image without distortion can be obtained. In addition, since the imaging device 3 can be tilted around the rotation fulcrum 22 at an angle that is easy for the operator to operate, work on the document table 2 is facilitated.

Next, the configuration of the imaging device 3 used in each of the above embodiments will be described with reference to FIG. The imaging device 3 includes a planar CCD 40, a lens 41, and a light source lamp 42 therein, irradiates light from the light source lamp 42 to the original 1, and reads the reflected light with the CCD 40. Specifically, the reflected light passing through the lens 41 is imaged on the CCD 40 and is photoelectrically converted. The output signal is subjected to image processing by an image processing device 50 described later. Here, the optical axis 5
Is a center line perpendicular to the light receiving surface of the CCD 40. Further, in order to read the original 1 positioned perpendicular to the optical axis 5 without distortion, the position and the inclination of the imaging device 3 are adjusted so that the optical axis 5 is located at the center of the image readable range B. . Note that the optical axis 5 is, of course,
It can be changed in any direction by an optical reflecting means such as a mirror.

Here, when the optical axis 5 and the mounting plate 8 are inclined, the read original image may be distorted, and thus the image is corrected by the image processing device 50 having the following configuration. That is, as shown in FIG. 7, the image processing device 50 includes a distortion correction unit 51, a shading correction unit 52,
The gamma correction unit 53, the CPU 54, and the memory 55 correct the distortion of the read original image, perform shading correction and gamma correction, and store the image data in the memory 55. Then, the image data is transferred to an output device 56 such as a personal computer or a printer, and is displayed or printed out. Here, the shading correction and the γ correction are performed by a known technique.

A first tilt detector 57 for detecting the tilt of the optical axis 5 and a second tilt detector 58 for detecting the tilt of the mounting surface 6 are provided. The optical axis 5 with respect to the mounting surface 6 based on the tilt data
Find the angle of Then, the distortion correction unit 51 corrects the image data by appropriately changing the interpolation or thinning ratio of the pixels of the image data based on the angle data.

As the tilt detectors 57 and 58, a rotary variable resistor (variom), a rotary encoder or the like is used.
At 0, the second tilt detectors 58 are attached to the pivots 21 of the mounting plate 8, respectively. Note that the first inclination detector 57 is
Although the inclination of the support 4 is detected, the imaging device 3
, The inclination of the optical axis 5 and the inclination of the column 4 correspond to each other, and the inclination of the optical axis 5 can be determined by detecting the inclination of the column 4.

When the original 1 as shown in FIG. 8A is read by the image reading apparatus of this embodiment, an image as shown in FIG. 8B is obtained. On the other hand, when the image is read by the conventional image reading apparatus shown in FIG. 3C, an image as shown in FIG. As can be seen from a comparison between the two, in the present image reading apparatus, since the optical axis 5 is inclined with respect to the mounting surface 8, each image reading from the image pickup apparatus 3 to both ends of the document 1 is performed. The distance is different. for that reason,
The image becomes larger toward the back of the document 1, and conversely, the image becomes smaller toward the front. Therefore, in the image interpolation or thinning-out process, the number of pixels to be interpolated or the number of pixels to be thinned out may be determined at a rate corresponding to each distance to both ends of the document 1. Note that a thick line C in the figure indicates an image of the document 1.

In the interpolation or thinning process, as shown in FIG. 9, lines L, M, and N are respectively drawn on the back side, middle, and front side of the read document image, and the arrangement of the pixels of the image data is determined at each position. read. Since the number of pixels in each line differs depending on the distance from the imaging device 3 to the corresponding portion of the document 1, the distortion ratio can be obtained from the number of pixels in each line. In the distortion correction processing by the interpolation processing, the number of pixels is increased from the line L to the line N in the longitudinal direction of the line according to the ratio of the degree of distortion. In the distortion correction processing by the thinning processing, the number of pixels is gradually reduced in the line longitudinal direction from the line L to the line N. As described above, in any of the processes, the distortion is corrected by adjusting the number of pixels read on the three lines so that the number of pixels finally becomes the same.

Here, even in the image reading apparatus of the third embodiment, the original image is distorted because the optical axis 5 is inclined with respect to the mounting surface 6, and this distortion is also caused by the image processing apparatus 50 having the above configuration. It is preferable to correct by In the image processing device 50 at this time, since the platen 2 is always horizontal,
The second tilt detector 58 for detecting the tilt of the mounting surface 6 becomes unnecessary.

As in the image reading apparatus of the first embodiment, when the support 4 is fixed to the document table 2 and the inclination angle of the optical axis 5 with respect to the mounting surface 6 does not change, the inclination of the optical axis 5 is set in advance. Is measured, and based on this inclination data,
What is necessary is just to perform the interpolation process or the thinning process of the read image.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention. For example,
As shown in FIG. 10, the imaging device 3 may be attached to the upper part of the column 4 via a pivot 23 to rotate the imaging device 3. Here, the placing plate 8 is provided on the platen 2, but the platen 2 may be fixed without the placing plate 8.

[0044]

As is clear from the above description, according to the present invention, by arranging the image pickup device so that the optical axis of the image pickup device is inclined with respect to the vertical direction, it is possible to reduce The imaging device can be located on the back side of the document. Therefore, the field of view of the operator is not obstructed by the imaging device, and workability on the document table can be improved. Further, by providing the distortion correcting means and correcting the read image data, it is possible to obtain an original image without distortion even when the optical axis is inclined with respect to the original table.

If the original table is inclined and the optical axis is perpendicular to the original table, an original image without distortion can always be obtained.
At this time, if a document reference plate for positioning the document is provided on the lower side of the inclined document table, the document can be prevented from slipping down and the document position can be kept constant.

Further, by making both or either one of the column supporting the imaging device and the mounting plate rotatable, the operator can incline the imaging device or the mounting plate to an angle that is easy for the operator to operate. Therefore, operability at the time of reading an image can be improved. And if a regulating member for regulating the inclination angle of the mounting plate is provided on the support,
An increase in the inclination of the mounting plate with respect to the horizontal plane makes it difficult to view the original and prevents a decrease in operability such as an increase in distortion.

[Brief description of the drawings]

FIG. 1 is a side view of an image reading apparatus according to a first embodiment of the present invention.

FIG. 2 is a side view of an image reading apparatus according to a second embodiment.

FIG. 3 is a side view of the image reading apparatus according to the third embodiment;

FIG. 4 is a side view of an image reading apparatus according to a fourth embodiment.

FIG. 5 is a side view of an image reading apparatus according to a fifth embodiment.

FIG. 6 is a schematic configuration diagram of an imaging device.

FIG. 7 is a control block diagram of the image reading apparatus.

FIG. 8 is a view showing image distortion due to a difference in inclination of an optical axis.

FIG. 9 is a view for explaining image distortion correction;

FIG. 10 is a side view of an image reading apparatus according to another embodiment.

FIG. 11 is a side view of a conventional image reading apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 document 2 platen 3 imaging device 4 support 5 optical axis 8 mounting plate 30 regulating member 50 image processing device 51 distortion correcting means 57 first tilt detector 58 second tilt detector

Claims (10)

[Claims] A first platen on which a document is placed facing upward;
An image reading device, comprising: an image pickup device that optically reads the document, wherein an optical axis of the image pickup device is inclined with respect to a vertical direction. 2. The image reading apparatus according to claim 1, wherein a support for supporting the image pickup device is provided on the document table, and the image pickup device is mounted obliquely with respect to the support. 3. The image reading apparatus according to claim 1, wherein a support for supporting the imaging device is provided on the document table, and the support is rotatable so as to be inclined backward with respect to a horizontal plane. 4. The image reading apparatus according to claim 1, wherein the mounting surface of the document table is inclined with respect to a horizontal plane. 5. The image reading apparatus according to claim 4, wherein the document table is rotatable so as to be inclined with respect to a horizontal plane. 6. The image reading apparatus according to claim 5, further comprising a regulating member for regulating an inclination angle of the document table. 7. The image reading apparatus according to claim 4, wherein a reference position for positioning the document is set on a lower side of the placing surface. 8. An apparatus according to claim 1, wherein the inclination angle of the front side of the optical axis with respect to the mounting surface is set to 90 degrees or more.
The image reading device according to any one of the above. 9. An image reading apparatus according to claim 1, further comprising a distortion correcting means for correcting distortion of an image of a document placed obliquely with respect to an optical axis. apparatus. 10. A first inclination detector for detecting the inclination of the optical axis, and a second inclination detector for detecting the inclination of the mounting surface, wherein the distortion correcting means includes an optical axis inclination and a mounting surface. 10. The image reading apparatus according to claim 9, wherein an interpolation process or a thinning process of pixels of the image data is performed based on the inclination of the image data.