JPH10341314A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To read a back cover, while closing a book and to simultaneously read the back cover and cover (or rear cover) of book by reading the end face of original, which is projected on a mirror when the original is placed on a platen, through an image-pickup device while scanning it. SOLUTION: In prescanning, data showing the terminal form of a book original 10 are read on a mirror 5, and original data on the cover (or rear cover) of book original 10 are provided on a platen 1. Next, in main scanning, the back cover of book original 10 projected on the mirror 5 is scanned, the image data of back cover area read, the cover (or rear cover) of book original 10 is scanned on the platen 1 based on the terminal form data of book original 10 provided in prescanning and the original data of cover, and the image data of cover are read. Since the read image data of back cover show mirror images, after output processing has been performed for inverting these images, they are outputted together with the image data of cover.

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 setting a thick original such as a book upward and reading the original from above, and more particularly, for reading a spine of a thick original such as a book while the original is closed. The present invention also relates to an image reading apparatus capable of simultaneously reading a spine and a front cover (or a back cover) of a thick original such as a book.

[0002]

2. Description of the Related Art In a conventional original reading type image reading apparatus in which a thick original such as a book is set upward and read from above, for example, as shown in JP-A-8-242347, a general Reads two pages on the left and right sides of a double-page spread of a document from above, but may also read the end face of the document (for example, the spine of a book). In this case, the book is opened downward, the spine is set upward, and the information on the spine is read by photographing with the image sensor provided above.

In order to read the front cover (or the back cover) in addition to the spine of the book, the book is opened downward and the spine is set upward and the information on the spine is read as described above. Thereafter, the book is closed, the front cover (or the back cover) is set upward, and the information on the front cover (or the back cover) of the book is read by photographing with the image sensor.

[0004]

However, in such a conventional document-upside-down type image reading apparatus, when reading the spine of a book, as described above, after opening the book, the spine is turned upward. Because of the setting, the binding part of the book was sometimes damaged.

When reading both the spine and front cover (or back cover) of a book, as described above, after reading the spine of a book, the front cover (or back cover) is read. Since it is necessary to perform two reading operations, the reading operation becomes troublesome and the reading operation is troublesome.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and allows a spine to be read while a book is closed, and a spine and a front cover (or a back cover) of a book to be read. It is an object of the present invention to provide an image reading apparatus capable of simultaneously reading image and image.

[0007]

According to a first aspect of the present invention, there is provided an image reading apparatus for optically scanning a document placed on a document table from above. A mirror arranged to be inclined rearward and rearward, an image sensor for scanning while scanning the document end face reflected on the mirror when a document is placed on the document table, and outputting an image of the document end face read by the image sensor. And output means for performing the operation.

According to the structure of the present invention, the image pickup device reads the original while scanning the original end face reflected on the mirror when the original is placed on the original table. The output unit inverts and outputs the image of the document end face read by the image sensor. As described above, the mirror is also used for reading an image, and the information reflected on the mirror is read as image information, so that the information on the document end surface (for example, the spine of a book) can be read with the document closed. it can.

According to a second aspect of the present invention, there is provided an image reading apparatus for reading a document placed on a document table by optical scanning from above, wherein the mirror is arranged to be inclined rearward and rearward of the document table. An image sensor for reading while simultaneously scanning the upper surface of the document placed on the document table and the document end surface reflected on the mirror, and output means for outputting both images of the document upper surface and the document end surface read by the image sensor. It is characterized by having.

According to the configuration of the present invention, the image pickup device reads the upper surface of the document placed on the document table and the document end surface reflected on the mirror while scanning simultaneously. The output means outputs both images of the document upper surface and the document end surface read by the image sensor. At this time, the image data of the document end surface is inverted and output together with the image data of the document upper surface. As described above, the mirror is also used for reading an image, and the information reflected on the mirror is read as image information, so that the reading operation can be performed by a single reading operation on the upper surface of the original (the front cover or the back cover of the book) and the end surface of the original (the original of the book). Both information on the spine can be read at the same time.

According to a third aspect of the present invention, in the image reading apparatus according to the first or second aspect, the number of pixels of the image sensor corresponding to an edge portion of the document end face read by the image sensor is detected. A distance measuring means for measuring a distance from the image sensor to the document surface based on the number of pixels; and an optical system for forming an image of a document on a document table on the image sensor based on a distance measured by the distance measuring means. And further characterized by:

According to the configuration of the present invention, the distance measuring means detects the number of pixels of the image sensor corresponding to the edge portion of the document end face read by the image sensor (this allows the height of the document to be obtained). The distance from the image sensor to the document surface is calculated based on the number of pixels. The optical system forms a document image on an image sensor based on the distance measurement value. In this way, the mirror is used for measuring the height of the original, and the information reflected on the mirror is used as the height information of the original to adjust the optical system. Can be taken.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an external view showing the entire configuration of an image reading apparatus according to an embodiment of the present invention. The platen 1
A thick original such as a book or file (hereinafter referred to as a “book original”), which is the subject, is placed upward with a spread state, and a line for reading the spread surface of the book original upward by optical scanning is provided above the thick original. An imaging camera unit 2 having a sensor is provided. The original placing surface of the platen 1 is colored darker than the background color of a general original,
When a book original is read with the original placing surface as a background, the original surface and the original placing surface can be identified. The apparatus includes an illuminating unit 3 arranged on the back side of the original table 1 for illuminating a book original on the original table 1 and an operation display panel 4 for setting image reading conditions and reading modes.
A mirror 5 arranged at an angle to the back side of the document table 1 and reflecting the end surface and end shape of the book document; a start key 6 for starting a reading operation; and a preliminary scan and a main scan of the imaging camera unit 2 And a control unit (see FIG. 7) for controlling the photographing operation. The image data captured by the imaging camera unit 2 is subjected to various processes by the control unit, and then output to a desired output device (for example, a printer, a computer, or the like).

The mirror 5 originally reflects the end face of the book document which is spatially curved in the height direction when the book document is placed upward with the book document opened on the document table 1. This is for detecting the height of a curved book document, thereby focusing on all sides of the book document in consideration of the height of the book document so as to obtain an image without blurring. . That is, the end shape of the book document reflected on the mirror 5 is read by the image capturing camera unit 2 and is converted into the height distance of the document surface by the number of pixels of the image sensor of the image capturing camera unit 2.

FIGS. 2 and 3 show schematic structures of the present apparatus as viewed from the front and the rear, respectively. Imaging camera unit 2
Denotes an imaging lens 7 which forms a part of an optical system for forming an original image on an image sensor and is driven by an autofocus (AF) motor; and a sub-scanning direction ( 2 (a direction indicated by an arrow in FIG. 2). The CCD line sensor 8 has a plurality of image pickup devices arranged in a line from the front side to the back side (main scanning direction) of the apparatus, and a part of the image pickup device has an end shape of a book document reflected on the mirror 5. Read the image. The book document 10 placed on the platen 1 is, for example, a book or a file that is closed at one end and has a columnar shape in which each page is spatially curved when opened left and right. The mirror 5 also serves as a document positioning stopper extending in the left-right direction on the back side of the document table 1, and is installed at an angle of 45 degrees with respect to the surface of the document table 1. The book document 10 is aligned by contacting the lower end of the mirror 5 with the upper end of the book document 10. Further, as described above, the document table 1 is colored darker than the background density of the document.

FIG. 4 shows the principle of distance measurement. By placing the book document 10 at a predetermined position on the document table 1, a mirror image 11 of the book document 10 is formed by the mirror 5. The mirror image of the document end surface is formed on the extension of the image of the document table 1 and is continuous with the document image. Note that the reading range of the image sensor is indicated by a dashed-dotted line 12, and the pixels (numbers) of the image sensor of the CCD line sensor 8 are indicated by 1 to n in order from the left in the drawing.

FIG. 5 shows image data read in the state of FIG. In the figure, a is an image of the original surface, b is an image of the original platen 1, c is an image of a background portion reflected on the mirror 5, d is an image of an end surface of the original reflected on the mirror 5, and e is a reference for positioning the original. Is shown. The image a of the document surface and the image d of the document end surface are read as curved in the main scanning direction due to a change in the height of the document. Since the document surface and the document end surface are generally colors close to white, they are read white. On the other hand, since the document table 1 is colored darker than the background of the document, and the image of the background portion reflected on the mirror 5 has a small amount of reflected light, both are read black.

Here, factors that determine the angle of the mirror 5 will be described. The mirror 5 has not only a function of simply obtaining a mirror image of the document end face, but also a function of applying illumination light to the document end face. As a result, distance measurement can be performed even on a document whose paper has changed to yellow after several years.
In addition, by photographing the document end surface from slightly below (that is, the front side), even if the document has a small thickness for several pages and it is difficult to recognize the end surface shape due to the density difference, the measurement is performed using the density difference from the document table 1. It is possible to do. In addition, if the photographing is performed from below, there is a possibility that an object other than the document is reflected in the field of view. These external objects usually have little effect on the distance measurement function due to low illuminance, out of focus, and the like. However, when light from an external light source directly enters the line sensor 8 via the mirror 5, an error may occur. From the above viewpoint, it is necessary to set the mirror angle in addition to the focal length and the angle of view of the imaging lens 7.

FIG. 6 shows an output example of one line in the main scanning direction read by the CCD line sensor 8. On the horizontal axis, the pixels (number) of the image sensor of the line sensor 8 (left side, back side,
The right (front side) and the vertical axis represent the output (image density) of each image sensor. Is the image c of the background portion reflected on the mirror 5,
Denotes an image d of the document end surface reflected on the mirror 5, denotes an image a of the document surface, and denotes an area on the image sensor of each image such as the image b of the document table 1. Dth is a predetermined threshold value for determining whether the image is a document image or another image, n1 and n3 are the minimum and maximum values of the pixel (number) of the image sensor having an output exceeding the threshold value Dth, and n2 is It is a pixel (number) of the image sensor corresponding to the alignment reference of the document and is a fixed value. (N2-n
1) is the number of pixels corresponding to the height of the document. Also, (n
3-n2-α) is the number of pixels corresponding to the size of the document in the front-rear direction. α is the amount of curvature of the lower end of the original due to the change in the height of the original, and is a value determined by the original height (n2-n1) of this portion. When the CCD line sensor 8 moves in the left-right direction (sub-scanning direction), the value of n1 changes, whereby the distribution of distance measurement values in the left-right direction of the document can be obtained. Also,
It is possible to detect a horizontal dimension at which all image densities decrease.

FIG. 7 shows a block configuration of a distance measuring circuit in the control unit. The output (image data) of the CCD line sensor 8 is A / D converted by an A / D converter 21 and then input to a comparator 22. The comparator 22 includes a CPU
23 sets a threshold value Dth in advance. When pixel data having a level exceeding the threshold value Dth is input to the comparator 22, the counter 24 is set. CP
U23 stores the minimum value n1 and the maximum value n3 of the count value of the counter 24. Thus, the distance corresponding to the document height can be obtained by conversion, and at the same time, the size of the document in the left-right direction can be obtained. The CPU 23 controls the lens driving device (AF motor) based on the obtained document height distance.
A control signal is output to the line sensor 26 and the lens 7 is moved in accordance with the reading position of the line sensor 8 so that an image such as a document surface is always focused on the line sensor 8 in a focused state. Further, the CPU 23 outputs a control signal to the sensor moving unit 25 and the lamp control unit 27 to control the scanning movement of the line sensor 8 and the lighting of the lamp of the illumination unit 3.

Next, the procedure of the reading operation according to the above configuration will be described with reference to the flowchart of FIG. When a reading start command is input, the lamp of the illumination unit 3 is turned on to illuminate the book document 10 (# 1). Then
Preliminary scanning for the distance measurement operation is started (# 2). In this distance measuring operation, while the CCD line sensor 8 is moved from one end in the sub-scanning direction, the number of pixels of the image sensor is counted by taking an image of the document end face and the document face reflected on the mirror 5. n1 and n3 are stored (# 3). This operation is repeated at regular intervals until the prescan for all lines is completed.
4) The original height and original size are calculated from the obtained count values n1 and n3 by calculation (# 5). When the above operation is completed, the CCD line sensor 8 is moved in the direction opposite to the pre-scanning direction to perform main scanning for photographing the book document 10 (# 6). At this time, focus adjustment and magnification change of the imaging lens 7 are performed based on the count value obtained in the preliminary scanning. Thereafter, when the main scanning is completed for all the lines, the lamp is turned off (# 7), and a series of image reading operations is completed. As described above, by performing the focusing operation of the imaging lens 7 in accordance with the height of the book document 10 photographed by the CCD line sensor 8, a beautiful image without blurring can be obtained.

As described above, the mirror 5 is originally intended to detect the height of the curved book document 10 to obtain an image without blurring. As described above, the end surface (spine) of the book document is projected on a mirror 5, and the mirror 5 is used to read the end surface (spine) of the book document.

FIG. 9 is an explanatory view showing how the book document 10 is set on the document table 1. When the book document 10 is set on the platen 1, the cover A (or the back cover) may be turned upward while the book document 10 is closed, and the spine B may be set to the back side, that is, the mirror 5 side. The document is placed so as to match the reference line 9 displayed on the document table 1. The image data of the cover A and the spine B of the read book document 10 are as shown in FIG. 10A, but the image of the spine B is a mirror image because the image reflected on the mirror 5 is taken. Is obtained in an inverted state. Therefore, when outputting the read image data, after inverting the image of the spine B, output image processing such as image distortion correction is performed.
Output data as shown in FIG. 10B is obtained.

FIG. 11 shows a case where the spine B of the book document 10 is photographed by the mirror 5 (hereinafter, "mirror reading mode").
FIG. First, as shown in FIG. 9, the book document 10 is set on the document table 1 with the spine B of the book document 10 on the back side and aligned with the reference line 9 (# 11), and read by the operation display panel 4. The mode is set to the mirror reading mode, that is, the mode for photographing the spine B of the book document 10 by the mirror 5 (# 12). Then, when the start key 6 is pressed (#
13), the lamp of the illumination unit 3 is turned on (# 14), the imaging camera unit 2 is scanned (# 15), and the spine B of the book document 10 reflected on the mirror 5 is read. When the reading operation is completed, the lamp of the illumination unit 3 is turned off (# 1).
6), a series of operations ends.

FIG. 12 is a flowchart showing the operation when the spine B and the cover A (or the back cover) of the book document 10 are photographed simultaneously (hereinafter, referred to as "mirror / document platen reading mode"). First, as shown in FIG.
The book original 10 is set on the original platen 1 with the cover A (or the back paper) of 0 facing upward and the back cover B facing the reference line 9 (# 21). The reading mode is set to the mirror / original plate reading mode by the display panel 4, that is, the back cover B and the cover A of the book document 10.
(Or the back cover) is set to a mode for photographing simultaneously (# 22). Then, when the start key 6 is pressed (# 2
3), the lamp of the illumination unit 3 is turned on (# 24), and the imaging camera unit 2 performs preliminary scanning (# 25). By this preliminary scanning, the mirror 5 obtains the height data of the end face (the spine B) of the book document 10 as described above, and
Then, image data of the front cover A (or the back cover) of the book document 10 is obtained. Next, the imaging camera unit 2 performs a main scan (# 26). By this main scanning, the mirror 5 obtains the image data of the spine B of the book original 10 and the platen 1 takes the data of the front cover A (or the back cover) of the book original 10 into consideration in consideration of the data obtained by the preliminary scanning. Obtain image data. When the reading of the image is completed, the lamp of the illumination unit 3 is turned off (# 27), and a series of operations ends.

FIG. 13 shows the relationship between various data in the mirror / original platen reading mode. In the preliminary scanning, as described above, the mirror 5 holds the book original 1
The data of the end shape of 0 is read, and the document table 1 obtains document data of the front cover A (or the back cover) of the book document 10. Next, in the main scanning, the mirror 5 scans the spine B of the book document 10 reflected on the mirror 5 to read the image data of the spine B, and the platen 1 scans the book document 10 obtained by the preliminary scanning. End shape data and cover A
(Or back cover) based on the manuscript data
Is scanned to read the image data of the front cover A (or the back cover). Then, since the read image data of the spine B is a mirror image, output image processing such as inversion is performed, and then the spine A
(Or the back cover) is output together with the image data.

FIG. 14 is a flowchart showing an example of the operation when outputting image data. In the output image processing of # 31, as described above, the image data of the spine B read in the main scan uses the image reflected on the mirror 5, and the image of the spine B is obtained as a mirror image. The image of the cover B is mirror-inverted and image correction is performed based on the angle and shape of the mirror 5. On the other hand, in the size recognition processing of # 32, regarding the size of the original on the original table 1, the height measurement by the mirror 5 and the difference between the output values of the CCD line sensor 8 between the book original 10 and the original table 1 are detected. Thus, the size of the cover A of the book document 10 is recognized. The size of the spine B is determined by aligning the book document 10 with the reference line 9 on the platen 1 to determine the relative position between the mirror 5 and the book document 10. It is recognized by detecting the difference between the output value of the CCD line sensor 8 and the output unit. Then, # 3
In the output setting of 3, the operation display panel 4 is operated to
As shown in FIGS. 15A and 15B, the setting of the ratio between the back cover B, the cover A, and the margin C in the output image, the setting of the output image layout (up and down, left and right, etc.), and the printing of the margin C Set the pattern (white or black). Thereafter, the obtained image output data is output according to the above setting (# 34).

[0029]

As described above, according to the first aspect of the present invention, it is possible to read the information on the end face of the original (the spine of the book) while the original is closed. The damage of the part can be prevented.

According to the second aspect of the present invention, it is possible to simultaneously read both information on the upper surface of the document (the front cover or the back cover of the book) and the end surface of the document (the spine of the book) in one reading operation. , An index of a book or the like can be created in a short time.

According to the third aspect of the present invention, in addition to the effects of the first or second aspect of the present invention, the original can be imaged while focusing on all surfaces of the original. An image with no image can be easily obtained.

[Brief description of the drawings]

FIG. 1 is an external view showing an entire configuration of an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of the apparatus as viewed from the front.

FIG. 3 is a schematic configuration diagram of the present apparatus as viewed from the side.

FIG. 4 is a diagram showing a principle of distance measurement in the present apparatus.

FIG. 5 is a diagram illustrating a state of image data when a book document is read.

FIG. 6 is a diagram illustrating an output example of one line in the main scanning direction read by a line sensor.

FIG. 7 is a diagram showing a block configuration of a distance measuring circuit of the present apparatus.

FIG. 8 is a flowchart showing a procedure of a reading operation.

FIG. 9 is an explanatory diagram showing how a book document is set on a document table.

FIG. 10 is a diagram showing read data and output data when a spine and a cover are simultaneously read.

FIG. 11 is a flowchart showing an operation in a mirror reading mode.

FIG. 12 is a flowchart illustrating an operation in a mirror / original platen reading mode.

FIG. 13 is a diagram illustrating a mutual relationship between various data in a mirror / original platen reading mode.

FIG. 14 is a flowchart illustrating an example of an operation when outputting image data.

FIG. 15 is a diagram illustrating an example of an image output.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Original platen 2 ... Image pick-up camera part 3 ... Illumination part 4 ... Operation display panel 5 ... Mirror 7 ... Image pick-up lens (optical system) 8 ... CCD line sensor (image pick-up element) 10 ... Book original A ... Cover or back cover (original) Top surface) B: spine (edge of document)

Claims (3)

[Claims] An image reading apparatus for reading an original placed on a platen by optical scanning from above, a mirror arranged to be inclined rearward and rearward of the platen, and a document placed on the platen. An image reading device, comprising: an image sensor for reading while scanning the document end surface reflected on the mirror when placed; and an output unit for outputting an image of the document end surface read by the image sensor. 2. An image reading apparatus for reading a document placed on a platen by optical scanning from above, comprising: a mirror arranged to be inclined rearward and rearward of the platen; and a mirror placed on the platen. And an output unit that outputs both images of the document upper surface and the document end surface read by the image sensor while simultaneously scanning the upper surface of the original document and the document end surface reflected on the mirror. Image reading device. And detecting a number of pixels of the image sensor corresponding to an edge of a document end face read by the image sensor.
A distance measuring unit that measures a distance from the image sensor to the document surface based on the number of pixels; and an optical system that forms an image of a document on a document table on the image sensor based on a distance measured by the distance measuring unit. 3. The method according to claim 1, further comprising:
The image reading device according to claim 1.