JP2006229685A - Distortion determination device for business form - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the distortion of a business form by measuring the distortion characteristics from the outline information on the business form of the acquired picture to compair with the registered characteristics. <P>SOLUTION: The distortion determination device for a business form which determines the distortion of the outline of a business form on the acquired picture is provided with a side divider for obtaining a side dividing point, where the side of the business form is divided; a distortion characteristic extractor for extracting an angle of the line segments in an intersection of each line segment as a distortion characteristic, by connecting the side dividing points of each opposing side with predetermined corresponding conditions; a distortion characteristic storage for storing the distortion characteristic in a standard condition beforehand as a reference distortion characteristic; and a distortion determination part for determining the distortion of the business form by comparing the reference distortion characteristic with the extracted distortion characteristic of the business form. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a form distortion determination apparatus that sets a form on a mat and determines the distortion of a form image using a non-contact scanner device that reads an image from above with a sensor unit.

Currently, non-contact scanners for acquiring images of various papers such as forms and identification documents brought in by customers are used in the counter business of financial sales offices. The non-contact type scanner is a type of scanner that acquires an image of a form by a camera installed above a mat portion on which the form is placed. In the counter business of a financial sales office, the non-contact type scanner is connected to the counter terminal of the financial sales office counter, and image acquisition control is performed. The non-contact type scanner has features such as a simpler operation for image acquisition and a shorter time required than a flat bed type scanner or a sheet feed type scanner. (For example, Non-Patent Document 1)
The form image acquired at the window is subjected to predetermined character recognition processing by an optical character recognition device, and the contents of entry are converted into data and used for financial transactions.
The prior art of the present invention will be described below.

<Conventional system configuration>
An overview of a conventional system is shown in FIG.
The conventional system includes a non-contact scanner device 101, an optical character recognition device 102, and a WS 103. The WS 103 includes input means such as a keyboard and display means such as a CRT.
In FIG. 6, the non-contact scanner device 101 is viewed from above. The non-contact scanner device 101 and the optical character recognition device 102 will be described later.
The WS 103 is a terminal for controlling the entire system, and a general PC or the like having a display unit such as a memory and a CRT (not shown) and an operation unit such as a keyboard mouse is used.
Here, the optical character recognition apparatus 102 is described as being realized by hardware, but may be software provided in the WS 103.

<Configuration of non-contact scanner device>
As shown in FIG. 7, the non-contact scanner device 101 includes a control unit 101c, a mat unit 101a, and an image acquisition unit 101b.
The control unit 101 c includes a control unit for the entire non-contact scanner device 101 and a communication unit with the optical character recognition device 102.
The mat unit 101a is a table for installing a form for acquiring an image. The mat portion 101a is represented by shading in FIG. 6, but a material of a color such as black that can be easily distinguished from the form on the image is used. As a result, the acquired form image has a mat portion as a background, so that the form appears to rise against the black background color. For this reason, it is possible to easily detect the sides of the form.
The image acquisition unit 101b is a camera using a CCD, a C-MOS, or the like that has a function of photographing a form on the mat unit 101a and converting it into image data.

<Configuration of optical character recognition device>
The optical character recognition device identifies the type of form from the acquired form image, further identifies the area of the form to be recognized, and performs character recognition.
As shown in FIG. 8, the configuration of the optical character recognition device 102 includes a control unit 102a, an image memory 102b, a form angle detection unit 102c, a format creation unit 102d, a format reading unit 102e, a character area correction unit 102f, and a character recognition unit. 102g. In addition, communication means (not shown) with the non-contact scanner device 101 and the WS 103 is included.

The control unit 102 a of the optical character recognition device 102 controls the entire optical character recognition device 102.
The image memory 102b has means for holding the form image data. Each processing unit can refer to the form image by appropriately referring to the image memory 102b.
The form angle detection unit 102c has means for detecting a form angle from the image. The corner of the form is detected by, for example, scanning an image and detecting the boundary between the background and the form part, that is, the form side based on the difference in pixel density. By tracking the obtained pixels as the sides of the form, it is possible to determine whether the change of the X or Y coordinate is reversed or the place where the change starts is a corner. Alternatively, a plurality of points can be arbitrarily selected from each form side, and a known technique such as Hough transform can be used to approximate each form side to a straight line or a curve, and the intersection point can be selected as a corner.
The format creation unit 102d has means for creating a format necessary for character recognition such as character region coordinates. The format creation unit 102d will be described later.
The format reading unit 102e provides a function for reading the contents of the format to other processing units.
The character area correction unit 102f has means for correcting the character area coordinates from the format. The character area correction unit 102f will be described later.
The character recognition unit 102g provides a function of recognizing characters by pattern matching with a character recognition dictionary (not shown).

<Format creation section>
As shown in FIG. 9, the format creation unit 102d includes a control unit 102d1, a format storage unit 102d2, and a character area coordinate setting unit 102d3. Moreover, it has a communication processing unit (not shown) with other processing units.

The control unit 102d1 of the format creation unit controls the entire format creation unit 102d.
The format storage unit 102d2 provides a function of storing a format necessary for character recognition such as character region coordinates in a format storage unit (not shown). Hereinafter, the format is acquired from the format storage unit.
The format stores relative coordinates from the corner (for example, upper left), which is the basis of the form, for each character area, along with the identification information of each form. Based on this information, the character recognition unit identifies the character area on the form image and recognizes the entered character.
The character area coordinate setting unit 102d3 receives the input operation of the operator who creates the format, and registers necessary information such as the type of dictionary used for character recognition in addition to the above coordinates as the format. Here, it is assumed that the operator inputs data to the format creation unit via the WS 103.

<Character area correction unit>
As shown in FIG. 10, the configuration of the character region correction unit 102f includes a control unit 102f1 and a character region position correction unit 102f2. Moreover, it has a communication processing unit (not shown) with other processing units.
The control unit 102f1 of the character area correction unit 102f controls the entire character area correction unit 102f.

  The character region position correction unit 102f2 corrects the character region from the coordinates of the upper left corner. Note that although the upper left corner is used here, the reference angle of the relative coordinate is the upper left corner. For example, all other corners such as the upper right corner can be used as a reference.

<Operation>
(A) Format Registration FIG. 11A is a flowchart at the time of registration in an optical character recognition system using a non-contact scanner. First, the image acquisition unit 101b reads a registered form placed on the mat unit 101a, and captures the acquired image into the image memory 102b (S101). Subsequently, the form angle detection unit 102c refers to the image memory 102b to detect four form angles on the image (S102). Subsequently, the character area coordinate setting unit 102d3 refers to the image memory 102b to display an image on the CRT of the WS 103, and the operator sets the character area (S103). Subsequently, the format storage unit 102d2 stores the form corner coordinates and the character area coordinates in the format together with the identification information of each form such as a sheet ID specified separately (S104).

(B) Reading time FIG. 11B is a flowchart at the time of reading in the optical character recognition system using the non-contact scanner. First, the image acquisition unit 101b reads a read form placed on the mat unit 101a, and captures the acquired image into the image memory 102b (S201). Subsequently, the form angle detection unit 102c refers to the image memory 102b to detect four form angles on the image (S202). Subsequently, the format reading unit 102e reads the format corresponding to the type of the form (form corner coordinates and character area coordinates of the registered image) (S203). Subsequently, the character area correction unit 102f2 of the character area correction unit 102f corrects the character area from the form angle coordinates / character area coordinates of the registered image and the form angle coordinates of the read image by the upper left corner coordinates of the form angle coordinates. (S204). Subsequently, the character recognition unit 102g recognizes the character (S205), and displays the character recognition result on the CRT of the WS 103 (S206). An image obtained by cutting out the character area is displayed as a confirmation image together with the character recognition result, and is often used for confirmation of the character recognition result.

The type of the form is specified by comparing the identification information extracted from the form image with the identification information registered in the format and selecting a matching format. As the identification information, a sheet ID, ruled line feature information, or the like is used.
Oki Technical Review January 2002 / No. 189 Vol.69 No.1 “Color Direct Scanner”

  As described above, the non-contact scanner has a structure in which an image is acquired by photographing a form placed on the mat portion with a camera from above, so when the image is acquired with the form raised from the mat, the form itself is Even if it is not distorted, the form is distorted on the image.

  FIG. 12B expresses the form distortion when the image is acquired with the upper left corner of the form raised. In such a case, since the corner of the character area of the form is shifted so that it extends to the upper left, when character recognition is performed, the character area is erroneously moved to the upper left as shown in the figure. Will correct. Since all character area positions on the form are determined with reference to the corner of one form, the other character areas are also shifted uniformly. For this reason, the entire form has an influence such as misreading of the character recognition result, blanking, or dropping of digits due to an actual entry character being out of the character area. In such a case, the confirmation image of the character area is also cut out in a shifted manner, so that it is not only difficult to correct, but also difficult to notice digit loss. For example, the character area in the lower right part of FIG. 12B is completely deviated from the actual entry position because the reference corner is shifted. In such a case, it may be regarded as blank even though there is actually an entry. In such cases, financial transaction accidents may occur.

  Therefore, when a form image in such a state is acquired, it is necessary to invalidate the image, correct the floating of the form, and cause the operator to acquire the form image again.

In order to solve such a problem, the form distortion determination apparatus of the present invention has the following configuration.
<Configuration 1>
A form distortion determination apparatus that acquires an image of a form and determines the distortion of the outer shape of the form portion on the image,
An edge dividing unit for obtaining an edge dividing point obtained by dividing an edge of the form part;
A distortion feature extraction unit that connects the side dividing points of the opposing sides according to a predetermined correspondence condition, and extracts the angle between the line segments at the intersection of each line segment as a distortion feature;
A distortion feature storage unit that previously stores the distortion feature in the standard state as a reference distortion feature;
A distortion determination unit that determines distortion of the form part by comparing the reference distortion characteristic with the extracted distortion characteristic of the form part;
<Configuration 2>
A corner detection unit for detecting a corner of the form part;
The side dividing unit obtains points obtained by dividing the lines connecting the detected corners, and divides the sides by associating the obtained points with the sides of the form part.
<Configuration 3>
The side dividing unit divides the division equally into a predetermined number.
<Configuration 4>
The side dividing portion shortens the interval of the division in a portion close to a corner.
<Configuration 5>
Add the length of each line segment connecting the side division points to the distortion feature,
The distortion feature storage unit stores in advance the distortion feature for each type of form in association with identification information for each type of form,
The determination unit obtains a distortion feature from a distortion feature storage unit based on the identification information of the form on the image, and performs distortion determination by comparing with the extracted distortion feature.
<Configuration 6>
A form image acquisition apparatus comprising the form distortion determination apparatus described above.
<Configuration 7>
A financial sales office terminal comprising the above-described form distortion determination apparatus distortion determination apparatus.

  The distortion of the form can be detected by measuring the form distortion feature from the outline information of the form on the acquired image and comparing it with the registered feature.

  Examples of the present invention will be described as follows.

<Configuration of Example 1>
An overview of this system is shown in FIG.
This system includes a non-contact scanner device 201, an optical character recognition device 202, and a WS 203. The WS 203 includes an input unit such as a keyboard and a display unit such as a CRT. Hereinafter, description of the same parts as those of the conventional system will be omitted.

<Configuration of non-contact scanner device>
The configuration of the non-contact scanner device 201 is the same as that of the conventional system.

<Configuration of optical character recognition device>
As shown in FIG. 1, the internal configuration of the optical character recognition device 202 includes a control unit 202a, an image memory 202b, a form angle detection unit 202c, a format creation unit 202d, a format reading unit 202e, a character area correction unit 202f, a character recognition. A section 202g, a side division section 202h, a form distortion feature extraction section 202i, and a form distortion determination section 202j.

  Since the control unit 202a, the image memory 202b, the form angle detection unit 202c, the character area correction unit 202f, and the character recognition unit 202g are the same as those in the related art, description thereof is omitted.

  The format creation unit 202d further includes a distortion feature registration unit 202d4 for registering reference distortion feature information serving as a criterion for distortion determination with respect to the configuration of the conventional system. The format creation unit 202d will be described later.

  The format reading unit 202e is a processing unit that provides a function of reading the contents of the format storage unit as in the conventional system. In this embodiment, the standard distortion feature registered in the format storage unit is further added. Has the function to read and output.

  The form distortion determination unit 202j uses the format reading unit 202e to acquire the reference distortion feature information from the format storage unit, and compares the distortion characteristic information extracted by the form distortion feature extraction unit 202i to determine the distortion of the form. Provide the function to do.

  The side dividing unit 202h provides a function for obtaining a side dividing point that is a reference for extracting each distortion feature by dividing each side of the form part under a predetermined condition. The side dividing unit 202h will be described later.

  The form distortion feature extraction unit 202i provides a function of extracting a form distortion feature from an image. The form distortion feature extraction unit 202i will be described later.

<Distortion feature information>
Here, the distortion feature information in the present embodiment will be described.
FIG. 5A shows a state in which distortion features are extracted from a form portion of a form image that is a basis for distortion information. Note that the density of the halftone dots is different from that in FIGS. 12 (a) and 12 (b), but this is for easy viewing of the characters, and the difference in density has no particular meaning.

In FIG. 5A, each symbol has the following meaning.
Te: Width of the upper side of the form part Be: Width of the lower side of the form part Le: Vertical width of the left side of the form part Re: Vertical width of the right side of the form part n: Number of divisions of the upper side and lower side m: Number of divisions of the left side and right side Vex (x = 1, 2,... N): Line segment connecting the upper side and lower side opposing side division points Hey (y = 1, 2,... M): Line segment connecting the left side and right side opposing side division points θeyx (y = 1, 2,... m) (x = 1, 2,... n): Angle of intersection of Vex and Hey Each extraction method will be described later.

  In the present embodiment, θeyx is extracted as distortion feature information using one reference form, and is stored in the format storage unit as common reference distortion feature information.

FIG. 5B shows a state in which distortion features are extracted from the form portion of the form image to be determined by the same process as in FIG.
FIG. 5B emphasizes and describes the distortion of the form when an image is acquired with the left corner of the form raised. The meaning of the symbol is the same as that in FIG. 5A, only that e is changed to r.

<Format creation section>
As shown in FIG. 3, the internal configuration of the format creation unit 202e includes a control unit 202d1, a format storage unit 202d2, a character area coordinate setting unit 202d3, and a distortion feature registration unit 202d4. Moreover, it has a communication processing unit (not shown) with other processing units.

  Here, the distortion feature registration unit 202d4 added to the conventional system will be described.

  The distortion feature registration unit 202d4 provides a function of registering, in the format storage unit, distortion feature information extracted for the form portion of the form image of the reference form. For example, when an operator gives a start instruction to the format creation unit via the WS 103, a series of processing from extraction of distortion feature information to registration in the format storage unit is performed.

  The format only needs to be registered in advance, and it is sufficient that the format registered in the format storage unit in advance can be referred to during operation. Therefore, the format creation unit 202d can be omitted during operation.

<Side division part>
The side dividing unit 202h provides a function of dividing the sides of the form part.
Hereinafter, processing when the side is divided by the side dividing unit 202h will be described.

First, the corner of the form portion is detected by the corner detection unit 202c as in the conventional system.
The side dividing unit 202h obtains a line segment connecting the detected corners. Subsequently, each of the obtained line segments is divided into equal intervals by a predetermined number. The predetermined numbers are n and m in FIGS. 5A and 5B, and the number of division points is constant regardless of the size of the input form. Subsequently, for example, if the upper side and the lower side are scanned, the pixel is scanned in the Y-axis direction (if the left side and the right side are the x-axis direction), and the points where the background color and the density of the form portion change are extracted. By doing so, it is possible to extract the edge dividing points of the respective document edges corresponding to the dividing points of the line segments.

<Form distortion feature extraction unit>
The form distortion feature extraction unit 202i obtains a line segment that connects the opposing points as shown in the drawing with respect to the side division points obtained by the side division unit 202h. These line segments are like Vex, Hey, Vrx, and Hry in FIGS. Subsequently, the angle θeyx of each intersection is obtained and output as a feature.

<Operation of Example 1>
(A) At Registration FIG. 4A is a flowchart at the time of registration of the reference distortion feature information in the optical character recognition system using a non-contact scanner. First, the image acquisition unit 201b reads a reference registered form placed on the mat unit 201a, and takes the acquired image into the image memory 202b (S301). Here, since it is necessary to acquire the image of the reference form in a state without distortion, it is necessary to place the image in a state in which there is no lifting or bending. This is called a standard state or a reference state.

  Subsequently, the form angle detecting unit 202c detects four form angles on the form image (S302).

  Subsequently, the side dividing unit 202h divides the sides of the form portion to obtain side dividing points (S303).

  Subsequently, the form feature extraction unit 202i extracts distortion feature information of the reference form image (S304).

  Subsequently, the distortion feature registration unit 202d4 registers the extracted distortion feature information in the format storage unit as reference distortion feature information. (S305).

  Note that all the angles included in the reference distortion feature information acquired in the standard state are considered to be approximately 90 degrees, so that all the angles are set to 90 degrees without acquiring the distortion characteristics in the standard state as described above. It is also possible to generate and register distortion feature information. However, if the distortion feature information in the standard state is acquired and the distortion feature information is actually extracted as described above, it is possible to eliminate the effects of distortion occurring in the standard state due to the characteristics of the camera lens and the like. , Accuracy can be improved.

(B) Reading time FIG. 4B is a flowchart at the time of reading in the optical character recognition system using a non-contact scanner. First, the image acquisition unit 201b reads a read form placed on the mat unit 201a, and takes the acquired image into the image memory 202b (S401).

  Subsequently, the form angle detection unit 202c refers to the image memory 202b and detects four form angles on the image (S402).

  Subsequently, the side dividing unit 202h divides the sides of the form portion and obtains side dividing points (S403).

  Subsequently, the form distortion feature extraction unit 202i extracts the form distortion feature of the form part of the image (S404).

  Subsequently, the format reading unit 202e acquires reference distortion feature information from the format storage unit (S405).

  Subsequently, the form distortion evaluation unit 202j calculates the form distortion evaluation value shown below, and compares it with each preset threshold value (θTHr) (S406). For example, it is determined that the form is distorted (S407), and a form reject is displayed on the CRT of the WS 203 (S408).

[Form distortion evaluation value]
θyx = | θeyx−θryx | (y = 1, 2,... m) (x = 1, 2,... n)
[Threshold of form distortion evaluation value]
The threshold value of θyx: θTHr
When the form is rejected, the transaction is once canceled, the operator confirms the lift of the form, corrects the warp of the form if necessary, and puts the form on the mat part 201a again, and the above processing Again.

  If there is no object exceeding the threshold, it is determined that the form is not distorted (S407), and the character area position correcting unit 202f2 of the character area correcting unit 202f determines the form angle coordinates / character area coordinates of the registered image, and the read image. The character area is corrected from the form corner coordinates by the upper left corner coordinates of the form corner coordinates (S409).

  Subsequently, the character recognition unit 202g recognizes the character (S410), and displays the character recognition result on the CRT of the WS 203 (S411).

  In this way, each side of the reference form image is divided by a predetermined value to obtain a side division point, and the angle of the intersection of the line segments connecting the respective sides is set as a reference distortion feature, which is a determination target when determining distortion. Since each side of the form image is divided in the same way as the reference form, and the angle of the intersection of the line segments connecting the same is also used as the distortion feature, by comparing with the reference distortion feature, distortion on the form image can be determined. The operator can be warned, the occurrence of a financial transaction accident due to the deviation of the character area can be prevented, and the confirmation load for the operator can be reduced.

  In addition, when the form is lifted up, the image distortion is detected and a warning is issued and the form is repositioned, so that the operator can immediately detect if there is a problem with the way the form is placed on the mat part 201a. It can be expected that the installation will be improved after learning.

  In addition, since only the angle of the intersection of the line segments connecting the side division points is characterized, the same number of intersections can be obtained even if the non-decision form is different in size from the reference form. Since common feature data can be used, registration is required only once, and image distortion including new forms can be determined.

  In the first embodiment, only the angle of the intersection of the line segments connecting the corresponding edge division points is used as the distortion feature. However, in this embodiment, the length of the line segment is also used as the distortion feature information. For this reason, since the reference distortion feature differs for each form type, the reference distortion feature information is registered for each format of each form.

<Configuration of Example 2>
The system configuration in the present embodiment zero is shown in FIG. Only the parts different from the first embodiment will be described below.

<Configuration of optical character recognition device>
The internal configuration of the optical character recognition device 202 is shown in FIG.
Since the control unit 202a, the image memory 202b, the form angle detection unit 202c, the character area correction unit 202f, and the character recognition unit 202g are the same as those in the related art, description thereof will be omitted.

  In the present embodiment, the format reading unit 202e has a function of acquiring the reference distortion feature for each format.

  The form distortion feature extraction unit 202i provides a function of extracting a form distortion characteristic from an image in the same manner as in the first embodiment, but in addition to the angle of the intersection of the line segments connecting the side division points, The length of the minutes is also extracted as feature information. The form distortion feature extraction unit 202i will be described later.

<Distortion feature information>
Here, the distortion feature information in the present embodiment will be described.
FIG. 5A shows a state in which distortion features are extracted from a form portion of a form image that is a basis for distortion information. The meaning of each symbol is the same as in the first embodiment.

In this embodiment, using a single reference form, Vex, Hey, and θeyx are extracted as distortion feature information and stored in the format as common reference distortion feature information. Here, unlike the first embodiment, the reference distortion feature needs to be registered for each type of form registered in the format.
Since FIG. 5B is the same as that of the first embodiment, description thereof is omitted.

<Format creation section>
The internal configuration of the format creation unit 202e is shown in FIG.
The distortion feature registration unit 202d4 stores the reference distortion feature in the format storage unit in association with the format of each form. For this reason, it is efficient to perform the reference distortion feature information together with the registration of the character information for each form.

<Form distortion feature extraction unit>
The form distortion feature extraction unit 202i obtains a line segment that connects opposite sides of the side division points obtained by the side division unit 202h. These line segments are like Vex, Hey, Vrx, and Hry in FIGS. Subsequently, an angle θeyx of each intersection is obtained and output as a feature together with the length of each line segment.

<Operation of Example 2>
(A) At the time of registration The operation in this embodiment is described with reference to FIG. About S301-S304, since it is the same as that of Example 1, description is abbreviate | omitted.

  In S305, the distortion feature registration unit 202d4 registers the extracted distortion feature information as reference distortion feature information in association with the format of the form.

(B) Reading The operation in the present embodiment is described with reference to FIG. Since steps other than S405 and S406 are the same as those in the first embodiment, description thereof is omitted.

  In step S405, the format reading unit 202e acquires reference distortion feature information corresponding to the form type of the form image from the format storage unit (405). An existing method is applied to specify the type of form. For example, feature information such as sheet ID and ruled line feature of the form is registered together with the format, and a format that matches the feature is selected. Good. Alternatively, a form type designation means may be provided to the WS operator, and the form type may be specified based on the designated information.

In S406, the form distortion determination unit 202j calculates a form distortion evaluation value using the following formula.
[Form distortion evaluation value]
Vx = | Vex−Vrx | (x = 1, 2,... N)
Hy = | Hey−Hry | (y = 1, 2... M)
θyx = | θeyx−θryx | (y = 1, 2... m) (x = 1, 2... n)
[Threshold of form distortion evaluation value]
Hx threshold: VTHr
Hy threshold: HTHr
The threshold value of θyx: θTHr
Compared to the preset threshold values (VTHr, HTHr, θTHr) (S406), if any one exceeds the threshold value, it is determined that the form is distorted as in the first embodiment (S407). ), Form reject is displayed on the CRT of the WS 203 (S408)

  In this way, each side of the reference form image is divided by a predetermined value to obtain a side division point, and the angle of the intersection of the line segment connecting the respective sides and the length of each line segment are registered for each form as a reference distortion feature. When determining distortion, each side of the form image to be determined is divided in the same manner as the reference form, and the angle of the intersection of the line segments connecting the respective lines and the length of the line segment are also distortion characteristics. Since the distortion on the image of the form can be determined by comparing with the feature, the distortion can be determined with higher accuracy than the first embodiment.

  In the above-described embodiment, the line connecting the corners is equally divided. However, since the distortion due to the lift of the form is closer to the corner of the form, the division interval of the part near the corner of the form is larger. By shortening and increasing the division interval of the center, that is, the part far from the corner, the distortion of the form part can be detected with higher accuracy when the density of the side division points is given. For example, by dividing the division intervals corresponding to n and m in FIGS. 5A and 5B using a trigonometric function, it is possible to shorten the division interval near the corner. For example, if the center of the side is set as the starting point = 0 and the corner of the side is set as the end point = π / 2 [rad], the points obtained by equally dividing the side can be mapped with a sine function so that the intervals become shorter as the angle becomes closer. For example, when the center to the corner is divided into three, the point 1/3 from the center is sin ((π / 2) × (1/3)) = sin (π / 6) = 0.5, so Maps to half the point to the corner. The point 2/3 from the center is approximately 0.87 times from the center to the corner by sin ((π / 2) x (2/3)) = sin (π / 3) = about 0.87. Mapped.

  In the first embodiment, the common reference distortion feature information may be registered once. However, the reference distortion feature information may be registered for each form by the method as in the second embodiment. For example, when there is a difference in distortion depending on the size of the form due to the characteristics of the camera lens or the like, the accuracy can be further improved by registering the reference distortion feature information for each form.

  In the above embodiment, the character recognition device has been described as performing the above distortion determination. However, since the object of the present invention is to detect the distortion of the form, the character recognition itself may be performed separately. Good. Accordingly, the functions of the character area correction unit 202f and the character recognition unit 202g in the configuration of the optical character recognition device 202 can be divided by, for example, providing the WS 203 with the functions. In this case, the optical character recognition device 202 functions as a form image distortion detection device.

Further, by combining such a distortion detection apparatus and the scanner apparatus 201, it is possible to function as an image acquisition apparatus having a form image distortion detection function.
Further, by combining such a distortion detection device and WS 203, it is possible to function as a terminal device having a form image distortion detection function. In particular, when WS 203 is a financial sales office window terminal, it can function as a financial sales office window terminal having a form image distortion detection function.

Functional block of optical character recognition device of the present invention System configuration of the present invention Functional block of format creation unit of the present invention Flow chart of the present invention Explanation of distortion characteristics of forms Conventional system configuration Functional block of conventional scanner Functional block of conventional optical character recognition device Functional block of conventional format creation unit Functional block of conventional character area correction unit Conventional flowchart Acquired image and area correction result at the time of form distortion

Explanation of symbols

201 Scanner Device 201a Matte Unit 201b Image Acquisition Unit 202 Optical Character Recognition Device 203 WS
202a Control section 202b Image memory 202c Form angle detection section 202d Format creation section 202e Format reading section 202f Character area correction section 202g Character recognition section 202h Side division section 202i Form distortion feature extraction section 202j Form distortion determination section

Claims (8)

A form distortion determination apparatus that acquires an image of a form and determines the distortion of the outer shape of the form portion on the image,
An edge dividing unit for obtaining an edge dividing point obtained by dividing an edge of the form part;
A distortion feature extraction unit that connects the side division points of the opposing sides according to a predetermined correspondence condition, and extracts the angle between the line segments at the intersection of each line segment as a distortion feature;
A distortion feature storage unit that previously stores the distortion feature in the standard state as a reference distortion feature;
A distortion determination unit that determines distortion of the form part by comparing the reference distortion characteristic and the distortion characteristic of the extracted form part;
Form distortion judgment device. A corner detection unit for detecting a corner of the form part;
The form distortion determination device according to claim 1, wherein the side dividing unit obtains points obtained by dividing the lines connecting the detected corners, and divides the sides by associating the obtained points with the sides of the form part. .   The form distortion determination apparatus according to claim 2, wherein the side dividing unit divides the division into a predetermined number of equal parts.   The form distortion determination device according to claim 2, wherein the side dividing unit shortens an interval of the division in a portion near a corner.   The form distortion determination apparatus according to claim 4, wherein the division interval is determined by mapping a position of a division point when equally divided by a trigonometric function. Add the length of each line segment connecting the side division points to the distortion feature,
The distortion feature storage unit stores in advance the distortion feature for each type of form in association with identification information for each type of form,
6. The determination unit according to claim 1, wherein the determination unit acquires a distortion feature from a distortion feature storage unit based on identification information of the form on the image, and performs distortion determination by comparing with the extracted distortion feature. The form distortion determination device described in 1.   A form image determination apparatus comprising the form distortion determination apparatus according to claim 1.   A financial sales office terminal comprising the form distortion determination apparatus distortion determination apparatus according to claim 1.

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