JPH096965A - Method for detecting end position of book image and device for reading thereof - Google Patents

Abstract

PURPOSE: To efficiently shorten a processing time by finding an irreducible processing range at each time from the book image. CONSTITUTION: At specific intervals W which are less than a half as wide as the difference between the narrowest width W1 in the object book in the lateral direction of the book 10 and the widest width W2 in an object slip 14, pixel values on a longitudinal sample line SL which is set at an optional position are checked, and border coordinates whose differences from the longitudinal coordinate of the lower end of the book are less than specific value are excluded from a group of longitudinal border point coordinates which greatly vary in pixel value from a background value on the sample line; when the remaining coordinate groups do not become <=2 groups having variance below a specific permissible value, an error is judged and when one group is left, its mean value is regarded as the longitudinal coordinate of the upper end of the book. When two groups are left, the mean value of the group having a smaller value is regarded as the longitudinal coordinate of the upper end of the book.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an edge position of a book image and a reading device, and more particularly, when reading a code unique to the book printed on the back surface of the book, the code reading is automatically performed. In the image of the size that fits the largest target book, the range for performing image processing for
The present invention relates to a method for detecting an edge position of a book image and a reading device that can limit the book to be actually read.

[0002]

2. Description of the Related Art In order to automatically read a code peculiar to a book printed on the back of a book, it is necessary to process the image of the book taken in by a television camera or the like.

At this time, the easiest method is to perform the reading process on the entire view image including the background captured by the television camera. However, in a method that does not limit the processing range, a book is used. The same process is performed on a background image that does not include an image, which is not only inefficient, but also takes time to process.

On the other hand, Japanese Laid-Open Patent Publication No. 1-9303 discloses a wafer pattern by performing a two-dimensional Fourier transform on a dictionary pattern consisting of an image of the wafer and only boundaries to obtain a position having the highest correlation value between the image pattern and the dictionary pattern. Discloses a method of determining the center position of the.

Further, Japanese Laid-Open Patent Publication No. 2-130688 describes a circuit for providing a dead zone region and limiting the search range to shorten the processing time.

[0006]

However, in Japanese Patent Laid-Open No. 1-9303, since the search range of an image is not limited to a place where a desired pattern may exist, the same image is used as the dictionary pattern. There is a problem in that a matching process is performed up to a background portion in which it is known that a pattern does not exist, and that a wasteful processing time is required.

Further, in the latter Japanese Patent Laid-Open No. 2-130688,
Although the processing range is limited, there is a problem that the method for obtaining the processing range itself is not given.

The present invention has been made to solve the above-mentioned conventional problems, and provides a method for detecting an edge position of a book image, which can accurately determine the edge position of the book image from an input image. The first purpose.

The present invention also provides a book image reading apparatus capable of efficiently reducing the processing time by obtaining the minimum processing range each time by utilizing the book image edge position detecting method. The second purpose is to provide.

[0010]

SUMMARY OF THE INVENTION According to the present invention, one end of a desired coordinate axis direction for detecting the end position of a book is aligned substantially parallel to the coordinate axis of the visual field image and is arranged on the background in the coordinate axis direction. When detecting the position of the other end of the book in the coordinate axis direction, the width of the narrowest target book in the direction perpendicular to the coordinate axis of the book and the target slip sandwiched between the end faces of the book The pixel value on the image brightness measurement line in the coordinate axis direction set at an arbitrary position is detected at a predetermined interval of half or less of the width difference of the widest one, and the pixel value on the measurement line largely changes from the background value. The coordinate of the boundary point in the coordinate axis direction is recorded, and the difference between the coordinate of the one end of the book and the coordinate in the coordinate axis direction is equal to or less than a predetermined value in the coordinate axis direction boundary point coordinate group obtained by the number of measurement lines. Excludes objects, and the remaining coordinate groups When there are no more than two groups with variations less than or equal to the capacity value, it is an error. When there is one group, the representative value is the coordinate of the other end of the book in the coordinate axis direction, and when there are two groups. Eliminates the group having a large value as the coordinate of the slip and sets the representative value of the group having a small value as the coordinate of the other end of the book in the direction of the coordinate axis, thereby achieving the first object.

Further, the coordinates of the boundary point in the direction of the coordinate axis are:
This is the time when the pixel value on the measurement line, which has been checked from one of the visual field images, exceeds a predetermined threshold value, and at that time, the process for the measurement line is terminated.

The average value of the coordinates of the boundary points in the group is used as the representative value of the group.

Further, in the book reading apparatus, the image pickup means and a predetermined position on the background within the visual field of the image pickup means are arranged substantially parallel to the coordinate axes of the visual field image and one end thereof is aligned with the book at the end position. With respect to the book positioning means for arranging in the coordinate axis direction for detection, and the direction orthogonal to the coordinate axis of the book,
The coordinate axis set at an arbitrary position at a predetermined interval that is not more than half the difference between the width of the narrowest item in the target book and the width of the widest item in the target slip that is sandwiched between the end faces of the book. Means for detecting the pixel value on the image luminance measuring line in the direction, means for recording the coordinate in the coordinate axis direction of the boundary point at which the pixel value greatly changes from the background value on the measuring line, and the number of measuring lines is obtained. In the coordinate axis direction boundary point coordinate group, a coordinate group whose difference from the coordinate of the one end of the book in the coordinate axis direction is a predetermined value or less is excluded, and the remaining coordinate group has two variations of a predetermined allowable value or less. When the number of groups is not within the range, it is an error. When the number of groups is one, the representative value is the coordinate of the other end of the book in the coordinate axis direction. When the number of groups is two, the group with a large value is selected. Exclude as coordinates of slip and have small value An image processing unit that performs a reading process only on a portion between the other end coordinate of the book and the one end coordinate of the book in the image using the representative value of the loop as the coordinate of the other end of the book in the coordinate axis direction, Regarding the coordinate axis direction of the book, the second object is achieved by performing the reading process only on the area where the book exists.

Further, when detecting the end position of the book in the desired coordinate axis direction with respect to the book in which the slip is sandwiched and arranged substantially parallel to the coordinate axis of the image, the end part of the book is appropriately spaced on the image. Set the image brightness measurement line parallel to the coordinate axis direction for position detection, measure the image brightness on the image brightness measurement line, record the coordinates of the boundary point at which the image brightness changes from the set value, and record it. By dividing the coordinates of the boundary points into a set that falls within a desired allowable value or less, and detecting the position of the book edge by using the set close to the coordinates of the other end of the coordinate set at one end as the coordinates of the book edge, The purpose of 1 was achieved.

Further, the interval between the measuring lines of the image brightness is set to be 1/2 or less of the narrowest book in the direction perpendicular to the coordinate axis direction for detecting the end position of the book among the books to be detected. It was done.

Furthermore, in the case of reading a picked-up image of a book in which a slip is sandwiched and arranged substantially parallel to the coordinate axes of the image of the image pickup means, the position of the end of the book is detected on the image at appropriate intervals. A detection unit that sets an image brightness measurement line parallel to the coordinate axis direction, detects the image brightness on the image brightness measurement line, and detects the coordinates of a boundary point at which the image brightness changes from a set value, and the detection unit. Image processing means for recording the coordinates of the boundary points detected by the image processing means, and the image processing means further divides the recorded coordinates into a set that falls within a desired allowable value, and is close to the coordinates at the other end of the coordinate set at one end. By detecting the edge position of the book with the set as the position coordinates of the edge of the book, and determining the area to be read by the edge position of the book detected by the recording means, by performing the image reading process,
The second object is achieved.

[0017]

In the present invention, with respect to the direction perpendicular to the coordinate axis for detecting the end position of the book, the width of the narrowest object in the book and the object sandwiched between the book end surface (usually the upper surface) Check the pixel value on the image brightness measurement line in the coordinate axis direction set at an arbitrary position at a predetermined interval of half or less of the difference in width of the widest item in the slip, and the pixel value on the measurement line is larger than the background value. The coordinates of the changing boundary point in the coordinate axis direction are recorded. The recorded boundary point coordinates in the coordinate axis direction correspond to, for example, the lower edge of the image (when the book is not on the measurement line), the upper edge of the slip, or the upper edge of the book, but the coordinate value is determined at the lower edge of the image. , Easily distinguished from the other two. Further, the upper edge of the slip and the upper edge of the book can be easily distinguished because the upper edge of the slip is always on the upper side.
In addition, since the interval between the measurement lines is less than half the difference between the minimum width of the book and the maximum width of the slip, the measurement line will always hit somewhere on the top of the book, and the top position of the book can always be found. .

The coordinates of the boundary point in the direction of the coordinate axis are set to the time when the pixel value on the measurement line examined from one of the visual field images exceeds a predetermined threshold value, and at that time, the process for the measurement line is performed. If you end the procedure, a simple process of comparing the small amount of data on the measurement line with the threshold value will be sufficient.Because the process is interrupted when the threshold value is exceeded, the end of the book Detection processing can be performed. Further, although the brightness of the book portion is variously different, since the background of the conveyor or the like can have a uniform desired brightness, the edge position can be stably detected by comparison with the fixed threshold value.

Further, by using the average value of the boundary point coordinates in the group as the representative value of the group, it is possible to obtain a highly reliable end position.

Further, when detecting the end position of the book in the desired coordinate axis direction with respect to the book in which the slip is sandwiched and arranged substantially in parallel with the coordinate axis of the image, the end of the book is displayed on the image at appropriate intervals. Set the image brightness measurement line parallel to the coordinate axis direction for position detection, measure the image brightness on the image brightness measurement line, record the coordinates of the boundary point at which the image brightness changes from the set value, and record it. It is also possible to divide the coordinates of the boundary points into a set that falls within a desired allowable value, and to detect the position of the book edge by using the set close to the coordinates of the other end of the coordinate set at one end as the coordinates of the book edge.

Further, the distance between the measuring lines of the image brightness is set to a half or less of the narrowest book in the direction perpendicular to the coordinate axis direction for detecting the end position of the book among the books to be detected. can do.

Further, in the case of reading a picked-up image of a book which is arranged substantially parallel to the coordinate axes of the image of the image pickup means and has a slip inserted therein, the position of the end of the book is detected on the image at an appropriate interval. A detection unit that sets an image brightness measurement line parallel to the coordinate axis direction, detects the image brightness on the image brightness measurement line, and detects the coordinates of a boundary point at which the image brightness changes from a set value, and the detection unit. Image processing means for recording the coordinates of the boundary points detected by the image processing means, and the image processing means further divides the recorded coordinates into a set that falls within a desired allowable value, and is close to the coordinates at the other end of the coordinate set at one end. It is also possible to detect the edge position of the book by using the set as the position coordinates of the edge of the book, determine the region to be read by the edge position of the book detected by the recording unit, and perform the image reading process.

[0023]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing the overall configuration of a book code reading system which is an embodiment of a book image reading apparatus according to the present invention. In FIG. 1, the belt conveyor 20 in which the belt moves from right to left is controlled by the controller 22, the lower end of the book 10 is aligned by the pusher 24, and the traveling direction position of the book 10 is fixed by the stopper 26. Then, the lower end of the book 10 is aligned and positioned within the field of view of the camera 30.

The field of view of the camera 30 is set so as to accommodate the largest of the target books, and the belt conveyor 20
The direction of the lower end of the books aligned by is aligned with the direction of one side of the view image of the camera 30.
The pusher 24 and the stopper 26 are components of the belt conveyor 20.

In response to the positioning completion signal from the controller 22, the image processing device 32 inputs an image from the camera 30, performs a book code reading process, and outputs the read book code to the outside through the communication line 34.

FIG. 2 shows a book 1 in the screen according to the present invention.
0, the book code 12, and the slip (slip) 14 sandwiched between the books 10 are shown in a positional relationship. The slip (slip) 14 is a strip-shaped slip that is sandwiched between books and is used for sales management and order replenishment of books, and is generally called a slip, and is hereinafter referred to as slip 14.

The book 10 and the slip 14 have an end where the slip 14 is sandwiched substantially parallel to the screen as an upper end and an opposite side as a lower end, and the longitudinal direction (binding direction) of the book 10 is a Y-axis direction and a width direction. Is the X-axis direction, the lower end side is on the Y-axis 0, and the upper end side is on the positive direction side of the Y-axis. Hereinafter, the positive direction of the Y-axis will be referred to as up and the negative direction of the Y-axis will be referred to as down.

A book code 12 is printed on the book surface. Although the position of the book code 12 on the book 10 is arbitrary, it is obvious that the book code 12 does not exist on the background (belt conveyor surface) 40 in the screen, and by not performing the reading process on this portion, The reading processing time can be shortened.

Since the address of the image data is continuous on the horizontal line and the adjacent line, it is effective to limit the processing range in the vertical direction rather than in the horizontal direction in order to reduce the processing time. . Therefore, in this embodiment, the processing range is limited only in the vertical direction.

Next, with reference to FIG. 2, a method for obtaining the existence range of a book in the vertical direction will be described.

First, for the purpose of checking the existence range of the book 10, the image brightness for one vertical line is sequentially checked, and its position is determined. Hereinafter, a vertical measurement line that sequentially checks the measurement of the image brightness is abbreviated as a sample line SL. The position of the sample line itself is arbitrary, but the sample line SL is set at a constant interval W over the entire image. The setting of the sample line SL is not performed every time in the process of processing the input image, but is performed in advance for all the input images in common.

The processing performed for each sample line will be described with reference to FIG. On the assumption that the book 10 exists in contact with the lower end of the screen, the pixels on the sample line are sampled at a constant interval H from the upper end of the screen, and the brightness (pixel value) of each pixel is checked. The right side of FIG. 3 shows how the luminance changes on the sample line. It is assumed that the surface of the belt conveyor, which is the background 40 on the screen, has a color having a substantially uniform low brightness. Assuming that the target book 10 has a sufficiently bright color as compared with this, for example, if the pixel values on the sample line are sequentially examined from the upper end of the screen, the brightness exceeds a certain threshold value at the point where the sample line collides with the upper end of the book. Therefore, this can be recorded as a boundary point and the processing can be interrupted.
The method for checking the pixel value of the sample line is not limited to this, and conversely, the pixel value on the sample line can be checked from the lower end of the screen.

As shown in FIG. 2, the sample line may reach the lower end of the screen without detecting the boundary position, but it may hit the slip 14 and detect the boundary position. Here, in order to reliably detect the upper end of the book, it is necessary to ensure that the sample line for detecting the upper end of the book exists. Therefore, in the present invention, the interval W is set to half or less of the difference between the maximum width W2 of the target slip 14 and the minimum width W1 of the target book 10. In this way, as shown in FIG. 4, even when a part of the upper end of the book is hidden by the wide slip 14, the gap W is always provided on either side of the slip.
Since a wider part (W3 on the left side in Fig. 4) appears,
At least one sample line is always set here.

Next, a method for obtaining the upper end of the book from the boundary point group obtained by the boundary detection processing on the sample line will be described with reference to FIG.
This will be described in detail with reference to FIG.

First, when the coordinates of the boundary points are substantially the same as the bottom edge of the book, that is, the bottom edge of the screen in this embodiment, these boundary points are excluded from the target of the process for obtaining the top edge of the book. The remaining boundary points are the top of the slip or the top of the book, which are
Each should have approximately the same vertical coordinate value.
Further, although it is not known whether the upper end of the slip is detected, the upper end of the book must be detected by the above sample line interval setting. Therefore, first, the distribution state of the boundary point group after excluding the lower end of the screen is examined to see if it is divided into two groups within the allowable errors Eb and Es, or if they have different distributions. Here, Eb is the allowable error of a group with small coordinate values corresponding to the top of the book, Es
Is the tolerance of a group of large coordinate values corresponding to the top of the slip. The upper end of the book is almost flat, but since the upper end of the slip has a notch, it is necessary to change the tolerance. Usually, Es is larger than Eb.

When the distribution is different from that of the two or less groups, the sample line passes over the book because of bad lighting conditions, bad threshold settings, or the book color being close to the background. However, it is not correctly detected with the upper edge as the boundary position, the direction of the book is different from the direction of the image, the shape is not rectangular, the slip is bent, etc. Since the upper end cannot be detected by the method of the present invention, an error occurs.

On the other hand, when one group is grouped within the error Eb, no slip is detected, and it is assumed that all boundary points are the book top coordinates, and the maximum value of the vertical coordinates thereof is the book top coordinates.

Further, when the book is divided into two groups, the slip is always above the upper end of the book. Therefore, the group having the smaller vertical coordinate value is taken and the average value thereof is taken as the upper end coordinate of the book. Even if the slip position is mistakenly recognized as the top of the book because the slip is inserted deeply and the sample line hits the position where the slip is low, there is little difference from the top of the actual book, so there is little waste. Also, since the book is definitely included in the processing range, there is no problem.

After obtaining the book upper end by the above method, the image processing device 32 performs the book code reading process on the portion between the book upper end and the book lower end (screen lower end in this embodiment) of the input image. , Read the result by telecommunication line 3
4 sends to an external display device or master computer.

FIG. 6 shows a processing procedure for detecting and reading a book code based on the above method.

First, in step S1, the controller 2
The belt conveyer 20 carries and positions the book in accordance with the control signal 2. In step S2, the camera 30 inputs the book image and sends it to the image processing device 32.

The subsequent processing is internal processing of the image processing device 32. In step S3, a vertical boundary point coordinate group is obtained by a boundary point detection process on a preset sample line. In step S4, the image bottom edge coordinates are removed from the boundary point coordinate group. In step S5, the remaining boundary point coordinate group is grouped into two.

Next, in step S6, it is determined whether or not the grouping is successful, and if the grouping fails, the process is interrupted and the process goes to step S7 to send an undetectable signal to the external display device via the communication line 34. It is sent to the master computer or the like, and the process returns to step S1.

On the other hand, if the grouping of two or less succeeds, the process proceeds to step S8, and the average value of the group having a small vertical coordinate value is obtained as the book upper end coordinate. In step S9, a book code reading process is performed on a portion sandwiched between the upper end of the book and the lower end of the book (the lower end of the screen in this embodiment), and in step S10, the reading result is the communication line 3
From step 4, the image is sent to an external display device, master computer, etc., and the process returns to step S1.

In this embodiment, since the lower end of the book is aligned and the upper end position of the book is detected, it is possible to reliably eliminate the influence of slip, which is often caught in the upper part of the book. When the slip is not inserted or when the influence of the slip is negligible, the book upper end can be aligned and the book lower end position can be detected.

Further, in the above-mentioned embodiment, the book is arranged on the belt conveyor, but the object on which the book is arranged is not limited to this, and it may be arranged on the fixed base.

Further, in the above-mentioned embodiment, the average value in each group is used as the representative value, but the maximum value is used as the representative value and the reading range of the book can be surely secured by a simple process. good. In addition, since the book code is usually printed with some margin from the end of the book,
Even if the average value in each group is used as the representative value as in the above embodiment, there is no practical problem.

Further, in the above embodiment, the interval between the sample lines SL is set to 1/2 or less of the difference between the maximum width W2 of the target slip 14 and the minimum width W1 of the target book 10. Is the minimum width W1 of the target book 10
It may be 1/2 or less. At this time, even if the upper end of the book 10 is hidden by the slip 14 and the book 10 is small and all the sample lines SL catch the slip 14, the book 10 is definitely included in the processing range, and the book 10 at this time is also included. Is small, the range of image processing is narrow,
Further, for most of the wide books 10, one or more sample lines SL catch the books 10, so there is no practical problem. In particular, when the minimum width W1 of the target book 10 exceeds twice the maximum width W2 of the target slip 14, one or more sample lines SL can surely catch the book 10.

Further, the interval between the sample lines SL may be set to the interval equal to or smaller than the minimum width of the book 10. Again,
Since most of the book 10 has a width sufficiently wider than the width of the slip 14, the sample line SL has a high probability of directly catching the book 10, and the size of the book 10 is large, which causes a problem of image recognition in a useless range. About 10 books, sample line S
Since the probability that L will catch the slip 14 is low, there is no practical problem.

In the above embodiment, the case where the vertical position of the book 10 is obtained has been described, but the direction of obtaining is not limited to this, and the horizontal position of the book 10 may be obtained.

Further, although the book 10 has one end fixed and the positions of the other ends determined, the positions of both ends may be determined without fixing the one end. At this time, for example, with respect to the vertical direction of the book 10, the book 1 in which the upper end side is arranged on the side having a larger coordinate value and the lower end side is arranged on the side having a smaller coordinate value, and a slip is sandwiched at the upper end side
When obtaining the upper end position and the lower end position in the vertical direction of 0, two boundary positions are obtained for one sample line SL. Next, the distribution state of the boundary points is investigated, and the group of small coordinate values and the group of large coordinate values are divided into groups with the small coordinate value as the lower end position of the book 10, and the group with large coordinate values is further described above. Are divided into a group showing the upper end position of the book 10 and a group showing the upper end of the slip 14. By doing so, the positions of both ends of the book 10 can also be detected.

[0053]

As described above, according to the present invention,
The edge position of the book image can be accurately detected from the input image.

Further, since the edge position of the book image can be detected, it is possible to provide the book image reading apparatus which can obtain the minimum processing range and efficiently reduce the processing time.

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of an embodiment of a book code reading device to which the present invention is applied.

FIG. 2 is a diagram showing a positional relationship among books, book codes and slips in an image in the embodiment.

FIG. 3 is a diagram showing a method of obtaining boundary point coordinates on each sample line in the embodiment.

FIG. 4 is a diagram showing an example of a relationship between a book width and a slit width in an image and a sample line spacing in the embodiment.

FIG. 5 is a diagram for explaining a method of obtaining a book upper end position from a boundary point coordinate group in the embodiment.

FIG. 6 is a flowchart showing the processing procedure of the embodiment.

[Explanation of symbols]

 10 ... Book 12 ... Book Code 14 ... Slip 20 ... Belt Conveyor 22 ... Controller 24 ... Pusher 26 ... Stopper 30 ... Camera 32 ... Image Processing Device SL ... Sample Line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masamitsu Sasaki 7-23, Minamisenju, Arakawa-ku, Tokyo Hitachi Techno Engineering Co., Ltd.

Claims (7)

[Claims] 1. A book arranged in parallel with the coordinate axis of the visual field image and having one end in the desired coordinate axis direction for detecting the end position of the book aligned with the other end of the book arranged in the coordinate axis direction on the background. When detecting the position along the coordinate axis, the width of the narrowest item in the target book and the width of the widest item in the target slip sandwiched between the book end faces in the direction perpendicular to the coordinate axis of the book. At a predetermined interval less than half of the difference of, the pixel value on the image brightness measurement line in the coordinate axis direction set at an arbitrary position is detected, and in the coordinate axis direction of the boundary point at which the pixel value greatly changes from the background value on the measurement line. In the coordinate axis direction boundary point coordinate group in which the coordinates are recorded and the number of measurement lines is obtained, exclude the ones whose difference from the coordinate axis direction coordinate of the one end of the book is a predetermined value or less, and the remaining coordinates The group has a variation of 2 or less within a predetermined allowable value. When the number of groups is less than 1, an error occurs. When the number of groups is 1, the representative value is the coordinate of the other end of the book in the coordinate axis direction. When the number of groups is 2, the group with a large value is used. Is excluded as the coordinate of the slip, and the representative value of the group having a small value is used as the coordinate of the other end of the book in the coordinate axis direction. 2. The coordinate according to claim 1, wherein the coordinate of the boundary point in the coordinate axis direction is a time point at which a pixel value on a measurement line checked from one of the visual field images exceeds a predetermined threshold value, and at that time point,
A method for detecting an edge position of a book image, characterized by terminating the process for the measurement line. 3. The method for detecting an edge position of a book image according to claim 1, wherein an average value of boundary point coordinates in the group is used as a representative value of the group. 4. An image pickup means, and a predetermined position on the background in the visual field of the image pickup means, substantially parallel to the coordinate axes of the visual field image, and in the coordinate axis direction for aligning one end to detect the end position of the book. With respect to the book positioning means for arranging, the width of the narrowest one in the target book in the direction perpendicular to the coordinate axis of the book, and the widest one in the target slip sandwiched between the book end faces. A means for detecting a pixel value on the image brightness measuring line in the coordinate axis direction set at an arbitrary position at a predetermined interval of half or less of a difference in width, and a boundary point at which the pixel value greatly changes from the background value on the measuring line. Except for a means for recording coordinates in the coordinate axis direction and a coordinate group in the coordinate axis direction boundary points obtained by the number of measurement lines, in which the difference between the coordinate in the coordinate axis direction at the one end of the book is a predetermined value or less. However, the remaining coordinate group is below the specified tolerance. If you do not have a group within 2 of the variation below,
If an error occurs and the number of groups is one, the representative value is the coordinate of the other end of the book in the direction of the coordinate axis. If the number of groups is two, the group having a large value is excluded as the coordinate of the slip, and the small value is used. Using the representative value of the group having the values as coordinates in the coordinate axis direction of the other end of the book, an image processing unit that performs a reading process only on a portion between the other end coordinate of the book and the one end coordinate of the book in the image. A reading device for a book image, which is characterized in that, at least with respect to the coordinate axis direction of the book, the reading process is performed only on an area where the book exists. 5. When detecting the end position of a book in a desired coordinate axis direction with respect to a book in which a slip is sandwiched and arranged substantially parallel to the coordinate axis of the image, the end of the book is displayed on the image at appropriate intervals. Set the image brightness measurement line parallel to the coordinate axis direction for position detection, measure the image brightness on the image brightness measurement line, and record the coordinates of the boundary point at which the image brightness changes from the set value, and record it. It is characterized in that the coordinates of the boundary points are divided into a set that falls within a desired allowable value, and the position of the book edge is detected by using the set close to the coordinates of the other end of the coordinate set at one end as the coordinates of the book edge. A method for detecting the edge position of a book image. 6. The book according to claim 5, wherein the distance between the measurement lines of the image brightness is the narrowest of the books to be detected, and the width in the direction perpendicular to the coordinate axis direction for detecting the end position of the book is the narrowest. A method for detecting an edge position of a book image, which is set to ½ or less. 7. A device for reading a picked-up image of a book in which a slip is sandwiched and arranged substantially parallel to the coordinate axes of the image of the image pickup means, the position of the end of the book is detected on the image at appropriate intervals. An image brightness measuring line is set parallel to the coordinate axis direction, the image brightness is detected on the image brightness measuring line, and the detecting unit detects the coordinates of a boundary point at which the image brightness changes from a set value. Image processing means for recording the coordinates of the boundary points detected by the image processing means, and the image processing means further divides the recorded coordinates into a set that falls within a desired allowable value and is close to the coordinates at the other end of the coordinate set at one end. A book characterized by detecting the edge position of the book by using the set as the position coordinates of the edge of the book, determining the area to be read by the edge position of the book detected by the recording means, and reading the image. Image reading Apparatus.