JPH01259474A - Character raw detector - Google Patents

Abstract

PURPOSE:To obtain the raw area of a small margin by detecting first-fourth coordinates to specify the circumscribed frame of a character raw and obtaining an area in the circumscribed frame specified by these first-fourth coordinates as a character raw area. CONSTITUTION:A character line detecting means regards a character picture element, which continues for less than a constant BTHL, as a noise and regards a character picture element, which continues only for the constant BTHL at least, as the prescribed character line to constitute a character graphic pattern. Then, the presence/absence of the prescribed character line and a starting edge coordinate XC1 are obtained. Accordingly, for example, since one independent character picture element is ignored as the noise and the presence/absence information of the prescribed character line and the stating edge coordinate XC1 are utilized for processing to detect the first-fourth coordinates, the detecting accuracy of the first-fourth coordinates can be improved. Thus, the area in the circumscribed frame specified by using these coordinates is obtained as the raw area. Thus, the raw area of the small margin can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a character line detection device for detecting an area defined by a circumscribing frame of a character line as a line area.

(Prior Art) Conventionally, in order to perform character recognition processing, image data is obtained by scanning an information medium such as a form or manuscript using a photoelectric converter, and the territory of a character line is detected from this image data. Next, one character's worth of image data is extracted from the detected line area. For example, JP-A-58-10
In the character cutting device disclosed in Japanese Patent No. 1374, a character line area is detected as described below for character recognition processing.

FIG. 8 is a diagram for explaining character line detection in the conventional apparatus described above, and shows an example of an input image of a horizontally written document and a histogram of the cumulative number of black pixels of this input image. Hereinafter, detection of character line areas in a horizontally written document will be described as an example.

First, the image data of the image within a predetermined rectangular area ABCD is scanned in the character line direction, the cumulative black pixels (pixels that constitute a character) on the scanning line are counted, and a histogram H of the cumulative black pixel count is created. . The creation of the histogram H is performed line by line by scanning the image data line by line.

Then, the section in which the histogram H exceeding a predetermined lIl@ exists is determined to be a character line section, and the section in which the histogram H below a threshold value exists is determined to be an interline section, and the area portion obtained by cutting the rectangular area ABCD at the boundary of these sections. (For example, the area portion indicated by hatching in the figure) was designated as the row area G.

(Problem to be Solved by the Invention) However, in the conventional device described above, the detected line area G includes a blank space of a form or the like where no characters exist. As a result, in image processing performed using the image data of the line area G, such as cutting out one character from the image data of the detected line area G, it is possible to scan the image data of the blank space of a form, etc. Therefore, there was a problem that image processing could not be performed efficiently.

Furthermore, since it is necessary to store the cumulative number of black pixels required for creating a histogram for each scanning line, a large memory must be prepared for creating the histogram. As a result, there was a problem in that the packaging size became large.

Roughly speaking, depending on the size of the threshold value for determining character line sections and line spacing sections, what should normally be determined as a text line section may be mistakenly judged as a line spacing section. Ta. For example, as shown in FIG. 8, if the threshold value is large, a portion of the histogram H of a character line with a small number of characters will be erroneously determined to be an interline interval. Furthermore, in order to avoid this, if the threshold value is set to a small value, if noise is present in the image data, what should originally be determined to be an inter-line interval will be incorrectly determined to be a line-to-line interval.

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, it is an object of the present invention to provide a character line detection device mainly for detecting line areas with fewer blank spaces.

(Means for Solving the Problems) In order to achieve this object, the character line detection device of the present invention detects a character line area by scanning image data including character figure patterns constituting the line. A character line detection device for detecting a character line area by scanning image data including character/figure punctuation that constitutes a line scans the image data in one direction. a character line detection means for detecting the coordinates of the first character pixel detected by scanning the image data in the other direction, and the coordinates of the first character pixel detected by scanning the image data in the other direction; When a character pixel is detected on the next scanning line, the scanning coordinates of the scanning line where the character pixel was detected are detected as the first coordinates for defining the circumscribing frame of the line, and the scanning in which the character pixel bubble was detected is performed. When a character pixel is not detected on the scanning line following the line, the scanning coordinates of the scanning line where the character pixel was detected are detected as second coordinates for defining the circumscribed frame, and the second coordinate is changed from the first coordinate to the second coordinate. The smallest coordinate of the character pixel coordinates detected on the scanning line from the first coordinate to the second coordinate is detected as the third coordinate for defining the circumscribing frame, and The present invention is characterized by comprising a character line detection control means for detecting the largest coordinate among the coordinates of the detected character pixels as a fourth coordinate for defining a circumscribing frame.

In carrying out the invention, it is preferable to scan image data on a scanning line in which a character pixel is detected by scanning in one direction in the other direction.

In carrying out the present invention, it is preferable to detect the coordinates of the first detected character pixel among a plurality of consecutive character pixels of a predetermined number or more.

In carrying out the invention, it is preferable that the character line detection means is a means for storing the coordinates of character pixels.

In carrying out the present invention, when no character pixel is detected on the scanning line following the scanning line in which the character pixel was detected, the detected first, second, third, and fourth coordinates are output. is suitable.

In carrying out the present invention, it is preferable to output the first, second, third, and fourth coordinates when a predetermined number or more consecutive scanning lines in which character pixels are detected occur.

In carrying out the present invention, when a predetermined number or more consecutive scanning lines in which no character pixels are detected, the first, second,
Preferably, the third and fourth coordinates are output.

In carrying out the present invention, it is preferable to adopt a configuration including a filter that determines the pixel value of a pixel of image data by using the pixel values of an arbitrary suitable number of other pixels in the vicinity of the pixel. It is.

Furthermore, in carrying out this invention, the direction along the rows is
It is preferable to use the main scanning direction of the image data.

(Operation) According to the character line detection device having such a configuration, the first to fourth coordinates for defining the circumscribing frame of the character line are detected. Therefore, by setting the area within the circumscribed frame defined by these first to fourth coordinates as the character line area, it is possible to obtain a line area with less margin than before.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are merely shown schematically to the extent that this invention can be understood, and therefore the configuration of each component, the arrangement position of each component, the input/output signals of each component, and the flow of input/output signals are shown in the drawings. , the operation and the flow of the operation are not limited to the illustrated example.

FIG. 1 is a functional block diagram for explaining the configuration of the device of the first embodiment.

In the figure, reference numeral 10 denotes a character line detection control means for detecting a character line area by scanning image data including character/figure patterns constituting a line. Character line detection means (hereinafter referred to as detection means) for detecting the coordinates of the first character pixel detected by scanning the image data in the other direction (referred to as means) 12, and
Rough character line detection control means (hereinafter referred to as control means) 1
4. Note that the character pixel referred to here is a predetermined pixel W (density) representing a pixel that constitutes a character graphic pattern.
shall mean a pixel that has .

The control means 14 detects the first, second, third and fourth coordinates for defining the circumscribed frame of the row as described in the following (1) to (2).

(2) When a character pixel is detected on the scanning line following the scanning line in which no character pixel was detected, the scanning coordinates of the scanning line where the character pixel was detected are detected as the first coordinates.

(2) When no character pixel is detected on the scanning line following the scanning line in which the character pixel was detected, the scanning coordinates of the scanning line in which the character pixel was detected are detected as second coordinates.

(2) Among the coordinates of character pixels detected on the scanning line between the first coordinate and the second coordinate, the minimum coordinate is detected as the third coordinate.

(2) Among the coordinates of character pixels detected on the scanning line between the first coordinate and the second coordinate, the largest coordinate is detected as the fourth coordinate.

Furthermore, the device H10 of this embodiment includes a P register 16 that stores determination information for determining whether or not a character pixel is detected in a scan line immediately before the current scan line, and a first coordinate. It includes a YT register 18 for detecting, a Y8 register 20 for detecting the second coordinate, an XL register 22 for detecting the third coordinate, and an XR register 26 for detecting the fourth coordinate.

Further, in FIG. 1, 2 indicates a reading device for obtaining image data of an information medium such as a form, and 30 indicates an image memory for storing image data output from the reading device.

The reading device M28 includes a photoelectric conversion unit 28a and a scanner (scanning mechanism) not shown. into an electrical signal, i.e. (input) image data.

For example, the photoelectric conversion unit 28a has a field of view of 2048x307
The optical signal G is divided into two pixels and converted into a binary digital signal for each pixel. The converted 21 signals are then output as image data. Image data from the photoelectric conversion section 28a is stored in the image memory 3o.

32 is a row position information storage section that stores the first to fourth coordinates detected on a row-by-row basis. The device 10 of this embodiment detects the first to fourth coordinates by scanning the image data stored in the image memory 3o, and outputs the detected first to fourth coordinates to the storage unit 32. .

This example will be explained in more detail below.

(Image Data) FIG. 2 is a diagram for explaining image data, and is a diagram showing an image of a horizontally written document as an example.

As shown in the same figure, the image data D includes a character/figure pattern D1 constituting a row and a background pattern D2 of the text/figure. And pattern D2? For example, pixel value rQJ
shall be expressed using white pixels. Therefore, in this embodiment, the character pixel is a pixel having a pixel value of "1".

The reading device 28 scans the horizontally written document within its field of view, with the direction along the row direction of the horizontally written document as the main scanning direction and the direction perpendicular to this direction as the subscanning direction, and reads the image data from this reading device 28. D is stored in the image memory 30. In the X-Y coordinate system shown in FIG. 2, the X-axis direction is the main scanning direction of the reading device M28, and the y-axis direction is the reading device T28.
The sub-scanning direction is set to .

Although the method for reading out the image data D from the image memory 30 does not matter, in this embodiment, each pixel position of the image data D is expressed in the above-mentioned X-Y coordinate system, and the X, Y coordinates of this coordinate system are
The image data DI of the pixel position specified by the coordinates can be read from the image memory 30. Then, the image data DI is scanned in the main scanning direction 8 of the image data D stored in the image memory 30 with the x-axis as the direction, and the sub-scanning direction is the direction along the y-axis. The second coordinates are Y coordinates Y1 and Y,
, and the X coordinates X and x6 are detected as the third and fourth coordinates.

The scanning range of the image data D is set arbitrarily and suitably, so that part or all of the image data D stored in the image memory 30 is scanned. Here, the coordinates for specifying the scanning range of image data D are X+, X2, Yl, and Y2.
Then, as shown in the figure, ×1 to ×2 and Y, to Y2
A rectangular range a surrounded by a dashed-dotted line in the range , is mainly the scanning range of the image data D.

(Character Line Detection Means) The detection means 12 of this embodiment scans image data on a scanning line in which a character pixel is detected by scanning in one direction in the other direction. Therefore, since scanning in the other direction is not performed for scanning lines in which no character pixels are detected, processing speed can be improved.

Furthermore, the detection means 12 of this embodiment detects the coordinates of the first detected character pixel among a plurality of consecutive character pixels equal to or greater than a predetermined number B THL (B THL is a constant set arbitrarily and preferably). . As a result, consecutive character pixels less than a predetermined number are treated as noise and are not used for detecting the first to fourth coordinates, thereby improving the accuracy of detecting the first to fourth coordinates. In the following description, for convenience of explanation, a character line consisting of consecutive character pixels of BTHL or more on a scanning line will be referred to as a predetermined character line.

In this embodiment, the detection means 12 is used as means for storing the coordinates of detected character pixels.

Furthermore, the detection means 12 includes, for example, an Xs register and an XE register that store coordinates X and x6 for specifying the main scanning start position and end position of the image data D, although not shown, and a sub-scanning of the image data. Ys register and YE that store coordinates Ys and YE for specifying the start position and end position
A register, and X for storing the scanning coordinates XSC and Ysc of the image data D.
,. Register and Y. A register, B for storing information as to whether image data C1 is being scanned, a register, and X for storing coordinates XC representing the scanning stop position M (or end position). register and the coordinate X of the first character pixel detected on the scan line. .

X to store. , a register, a B counter that counts the number 818 of character pixels consecutively detected on the scanning line of the image data D, a DIR register that stores information specifying the scanning direction of the image data, and a DIR register that stores information specifying the scanning direction of the image data. It is equipped with a DADD register to store a corresponding constant @ DADD @. Note that the constant value DADD is a constant value that is added to the scanning coordinate XSC in order to scan the image data of the next pixel.

The detection means 12 operates, for example, as follows.

A detection means 12 is used to detect the coordinates of the first character pixel detected on the scanning line by scanning in one or the other direction.
First, the image data on the scanning line is scanned in the i-direction.

If a predetermined character line is not detected on a scanning line during scanning in one direction, the image data of the scanning line next to the scanning line is scanned in one direction. When the detection means 12 finishes scanning the scanning line minus the line without detecting a predetermined character line (that is, when the scanning coordinate XSC becomes X5C=XE+1),
Save X5C=XE+1 as the scanning stop coordinate X0.

Further, when a predetermined character line is detected on the scanning line during scanning in the force direction, the detection means 12 stops its operation. For example, when the detection means 12 detects the BTHLth character pixel of a predetermined character line, it scans the scanning coordinate XSC of this BTHLth character pixel to the scanning stop coordinate X. Close, save, and stop working. By stopping the operation when the BTHL-th character pixel is detected, it is not necessary to scan all of the character pixels constituting a predetermined character line, so that processing speed can be improved.

Next, the scanning line on which a predetermined character line has been detected during scanning in one direction is scanned in the other direction, and when the predetermined character line is detected on the scanning line during scanning in the other direction, the detection means 12 stops its operation. Similar to the scanning in one direction, in this scanning in the other direction, the detection means 12 detects, for example, B of a predetermined character line.
The scanning coordinate XSC of the THLth detected character pixel is saved as the scanning stop coordinate Xc, and the operation is stopped.

In this way, when a character pixel of a predetermined character line is detected by scanning in one direction, the detection means 12 scans the scanning line where the character pixel was detected in the other direction, and then scans the scanning line of the sentence in one direction. Scan to. Therefore, since not all pixels on the scanning line where character pixels are detected are necessarily scanned, processing speed can be improved.

Also, the scanning stop coordinate x detected as described above. teeth,
When a predetermined character line is detected, Xs≦Xc≦XE when scanning in one direction, and XE≦Xc≦Xs when scanning in the other direction. When the scanning line-to-line scanning is completed without roughly detecting a predetermined character line, the scanning stop coordinate xo is x in one and the other scanning. =X
, +1. Therefore, for example, the scanning stop coordinate X. can be used as information on whether a character line is detected on a scanning line.

The detection means 12 stores the coordinates of the first (first) detected character pixel of a predetermined character line as the starting end coordinates XCI.

(Character Line Detection Control Means) The control means 14 of this embodiment detects the detected first, second, third, and Output the fourth coordinate. As a result, for each row within the scanning range a of the image data D, the first,
It is possible to detect Y, Ye, XL, and XR as the second, third, and fourth location marks.

Then, the control means 14 controls, for example, coordinates X1, . It includes an x register, a x2 register, a Y register, and a Y2 register that store X2, Yl, and Y2, and a Y register that stores a coordinate Y for specifying a sub-scanning position.

The principle of detection of the coordinates YT, Ye, XL and X, I will be briefly described below.

As is clear from Figure 2, the circumscribed frame F of the row is the point (XL
, YT ), (X,, Y□), point (XL, Ye),
A rectangular frame is obtained by connecting the four points (x*, Ye).

Here, if we consider the case where the line area in which the character pattern D1 constituting the - unit line exists is sequentially sub-scanned in the positive direction of the y-axis, character pixels (@ is a predetermined character line) are detected. Scanning of one unit of line area begins when a character pixel is detected on the scan line S next to the scan line where the character pixel was not present, followed by the scan line S in which the character pixel is detected, and then the character pixel is detected on the next scan line S. When no character pixels are detected on the scanning line S next to the detected scanning line S, scanning of one unit of line area ends.

Therefore, when a character pixel is detected on the scanning line S next to the scanning line where no character pixel was detected, the sub-scanning coordinate of the scanning line S where the character pixel was detected becomes the first coordinate YT to be detected, and When a character pixel is not detected on the scanning line S next to the scanning line S where a character pixel was detected, the sub-scanning coordinate of the scanning line S where the character pixel was detected becomes the second coordinate Y8 to be detected. I can understand.

Roughly speaking, considering the size of the X coordinate of character pixels detected between sub-scanning coordinates YT-YB, the
Among the coordinates, the minimum X coordinate is the third coordinate XL,
It can be understood that the maximum X coordinate is the fourth coordinate xR.

In order to detect the first to fourth coordinates according to such a detection principle, the control means 14 operates as described below, for example.

The control means 14 mainly includes the detection means 12 and the P register 1.
6. By controlling the Y□ register 18, Y8 register 20, XL register 22, X□ register 24 and Xl, l register 26, coordinates YT, Y8, XL and XR
Detect.

That is, when a character line is detected on the scanning line S, the control means 14 stores information indicating that a character line has been detected, for example, "rl" in the IP register 16, and detects the character line on the scanning line S. If the line-to-line scanning is completed without detecting a character line, information indicating that no character line has been detected, such as "O", is stored in the P register 16. The control means 14 is
When rewriting the information in the P register 16, the information in the P register 16 is rewritten so that the presence/absence information of a character line regarding the scanning line one line before the scanning line being scanned is saved.

If the information in the P register 16 is "0" when a predetermined character line is detected, the control means 14 determines the sub-scanning position of the scanning line S where the character line is detected at the coordinate Yy to be detected. It is saved in the YT register 18 as .

Furthermore, each time a predetermined character line is detected, the control means 14 saves in the Ya register 20 the sub-scanning position of the scanning line S where the character line is detected. When a predetermined character line is not detected on the scanning line S, the information in the P register 16 becomes "1".
'', the sub-scanning position of the scanning line stored in the Y8 register 20 is the coordinate Y8 to be detected.

When a predetermined character line is detected by scanning in one direction, the control means 14 converts the starting end coordinate XCI detected by scanning in one direction into the content of the XL register 22 (candidate of the coordinate X to be detected). , hereinafter referred to as XL candidate).If Xc+<(Xt candidate), the starting end coordinate XCI is stored in the register 22 as a new XL candidate.
Starting point coordinate X. Comparison of 1 and XL candidates and rewriting of XL candidates according to the comparison results means for each scanning line S (unit)
It will be held in

Therefore, if the information in the P register 16 is "]" when a predetermined character line is not detected during scanning in one direction, the XL candidate stored in the xL register 22 at this time is at the coordinate Y, up to Y8. This is the smallest XL candidate among the XL candidates detected on the scanning line between the two, and therefore the coordinate X to be detected.

Further, when a predetermined character line is detected in the scanning in the other direction, the control means 14 controls the starting point coordinate X detected in the scanning in the other direction.
. , the contents of the XR register 26 (coordinates to be detected
+ candidate (hereinafter referred to as XR candidate). And X
. , > (X* Candidate), the start end coordinate XC+ is stored in the XR register 26 again as a new X, I candidate. Comparison of starting end coordinates XCI and XR candidates and X according to the comparison results
, rewriting of the candidates is performed for one line (unit) of the scanning line S.

Therefore, if the information in the P register 16 is "1" when no character line is detected on the scanning line S, then
The ×8 candidate stored in the register 26 is the largest XR candidate among the ×5 candidates detected on the scanning line between the coordinates Y and Yll, and therefore becomes the coordinate XR to be detected.

(Operation) The operation of the device 10 of the first embodiment will be described in more detail below with reference to an operation flowchart. It is assumed that the coordinates XI, X2, Yl, and Y2 for specifying the scanning range have been input to the device M10 in advance.

3(A) and (8) are operation flowcharts of the character line detection control means, and FIG. 4 is an operation flowchart of the character line detection means.

First, the operation of the character line detection control means in FIGS. 3(A) and (B) V? In contrast, the control means 1
Operation No. 4 will be explained.

When the scanning of the form or the like by the reading device I28 is completed and therefore the storage of the image data D in the image memory 30 is completed, the control means 14 starts its operation (START).

In this example, the coordinates X+, X2, Yl and Y2 are
The information is input in advance to the control means 14, for example, as fixed data or rewritably via the keyboard.

The control means 14 that has started the operation sets r X 2 +I J 'a X L register 22 as the initial value of the XL candidate.
Set rX+ - ]J in the xR register 26 as the initial value of the XR candidate (Sl), set oJ as the initial value in the P register 16 (S2), and set 'Y+J! as the sub-scanning position in the Y register. (S3) Setting the initial value roJ'lr in the P register 16 means imagining a scanning line -line before the first scanning line scanned after starting the scanning of the image data D, and This indicates that it is assumed that no character line was detected in the scan line that was scanned.

Next, the control means 14 sets the xs coordinate to the rX+JtXs register, and sets "x2" to the x6 register as the x6 coordinate.
The sub-scanning coordinate '/sc is stored in the rYJ'&Ysc register, and information specifying the scanning direction, for example, rOJVDIR.
Set it in the register (S4).

In this embodiment, for example, "0" is used as the information that the scanning direction is one direction, and "1" is used as the information that the scanning direction is the other direction.

Next, the control means 14 outputs an activation signal to the detection means 12 (S5), and as a result, the detection means 12 starts an operation for detecting a predetermined character line on the scanning line (*
5TART, see Figure 4).

The control means 14 controls whether the detection means 12 detects a predetermined character line and stops its operation, or finishes scanning line-to-line without detecting a predetermined character line and stops its operation. The state in which the control means 14 or the detection means 12 are almost stopped and the detection means 12 is scanning for character line detection is expressed as BIJSY in FIG. 3 (△).

When the detection means 12 starts its operation, it sends information indicating that scanning is in progress, for example "1" to 8. Save in register. Further, when the detection means 12 detects a character line or finishes scanning from one scanning line to another, it stores information indicating that scanning has been stopped or finished, such as roJ%. Therefore, the control means 14
When outputting an activation signal to the detection means 12, the controller checks the information stored in the register (S6) and determines whether or not the detection means 12 is scanning. B. Checking the register is B.
This process is repeated until the information in the u register becomes "○".

The information in the Bu register becomes "0", so the detection means 1
2 stops operating, the control means 14 detects the detection means 12. The information stored in the register Xct is checked (S7) to determine the presence or absence of a character line on the scanning line. Depending on the result of the check in S7, the control means 14 operates as described in the following (1) to (2).

(2) When a predetermined character line is detected on the scanning line If the check in S7 shows that X, ≦XC≦X, this indicates that the detection means 12 has detected a predetermined character line on the scanning line.

Therefore, the control means 14 stores the coordinate Y, which is the sub-scanning position of the scanning line where the character line was detected, in the Y8 register 20.
8) , the starting end coordinates X of a predetermined character line. .

and the XL candidates in the XL register 22 are compared (S9).

By this comparison, if Xc+<(XL candidate), this
The CI is stored as a new X candidate in the XL register 22, and the XL candidate is rewritten, S10).The XL candidate is not rewritten unless Xc+<(XL candidate).

By rewriting the XL candidate only when XCI<(XL candidate) in S10, the minimum XL candidate (that is, the coordinate XL to be detected) can be detected in the - unit row.

Next, in order to scan the scanning line in which the predetermined character line has been detected in the other direction, the control means 14 sets 'X2 J as the xs coordinate.
'#Xs register, X, coordinate 'X+J'&X
Enter “YJ’/s” in the E register as the sub-scanning coordinate YSC.
c register, and further set it in the rlJVDIR register as information for specifying the scanning direction (Sl
l).

Next, the control means 14 outputs an activation signal to the detection means 12 (S12).

The control means 14 then checks the information stored in the Bu register of the detection means 12 (S13).

The information check of the Bu register is repeated until the information of the Bu register becomes rQJ.

The information in the BU register becomes "O", so the detection means 1
2 detects a predetermined character line and stops its operation, the control means 14 compares the starting end coordinate XCI of the predetermined character line detected by scanning in the other direction with the X of the ×8 register 26 and the candidate ( S14) As a result of this comparison, the control means 14 sets X at this time if XCI>XR. Iwo new X,
Rewriting the XR candidate to be stored in the XR register 26 as a candidate (S 15 ), the ×6 candidate is not rewritten unless XCI>XR. By rewriting the xR candidate only when Xc+>XR in S15, it is possible to detect the maximum XR candidate (ie, the coordinates XR to be detected) in the - unit row.

Next, the control means 14 checks the information stored in the P register 16 (S16).

The information stored in the P register 16 is "0" when checked in S16.
If so, it means that the predetermined character line was detected in the scanning line following the scanning line in which the predetermined character line was not detected, so the control means 14 controls the sub-scanning of the scanning line in which the predetermined character line was detected. The position 1tY is stored in the YT register 18 as the coordinate Y (S17). Then, information "1" indicating that a predetermined character line has been detected is stored in the P register 16 (S 1
8).

Also, by checking in S16, the information stored in the P register 16 is “
If it is not "○" (therefore, if it is "1"), it means that the predetermined character line has been detected in the scanning line next to the scanning line in which the predetermined character line was detected, so the control means 14 performs the steps S17 to S18. processing is not performed.

In S17, only when the information in the P register 16 is "○", the sub-scanning position ICY of the scanning line where the character line was detected is stored in the Y register, thereby storing the coordinate YT to be detected in the - unit line. I can do it.

Next, the control means 14 determines that the sub-scanning position WY of the scanning line is YE.
It is checked whether the image data has been scanned until (=y2) (S19). If Y=Y2, it means that scanning has been completed for the entire range of image data in the scanning range, so the control means 14 ends the operation (END).
If it is not Y-Yz, it means that scanning has not been completed for the entire range of image data in the scanning range, so in order to scan the image data on the next scanning line, the sub-scanning position 1tYtrlJ
520) and returns to S4.

■When no character line is detected on the scanning line, the check in S7 results in Xc+register storage information X.

is X. If = Xe + 1 (= The information stored in the register 16 is checked (S21).

If the stored information is "1" in the check at S21, the control means 14 stores information in the roJ8P register 16 indicating that no character line was detected in the scanned line (
S22).

Also, if the stored information is "1" when checking 521, it means that the specified character line was not detected in the scanning line following the scanning line in which the specified character line was detected, and therefore, regarding one unit line. This indicates that the coordinates YT, Y, , X, and XR have been detected, so the control means 14 reads the coordinates Y□, Ys, XL, and Write (S23)
.

Next, the control means 14 sets X to the initial value rX2 in the register 22.
The +IJ and XR registers 26 are stored with the initial value "x1-]" (524), and the process proceeds to S19, where operations are performed according to the determination result of S19.

Also, if the stored information is not "1" in the check in S21 (
Therefore, if rQJ), it means that the predetermined character line was not detected in the next scan line after the scan line in which the predetermined character line was not detected, so steps 322 to 24 are not performed after S21. Then, the process of S19 is performed.

II: Operation of character line detection means Next, the operation of the detection means 12 will be explained with reference to FIG.

The detection means 12 starts an operation for character line detection upon input of the activation signal from the control means 14 (*5TART
).

The detection means 12 that has started its operation stores information indicating that scanning is in progress in the BU register, for example, "1" (Sl), and further DI
Check the information stored in the R register (*S2).

*If the stored information in the check in S2 is information specifying one-way scanning, for example "0", the detection means 12 detects the constant value D.
By storing ADD in the r I J 7j DADD register (*S3) and setting DADD=1, the image data on the scanning line is scanned in the positive direction of the X axis (the direction in which the x coordinate increases).

Also, if the stored information is not "O" in the check of *S2, but information specifying scanning in the other direction, for example, "1", the detection means 12 sets a constant value of 0A00 to, for example, r - I J
! Store in the DADD register (*S4). DADD
By setting = -1, the image data on the scanning line is scanned in the negative direction of the X axis (the direction in which the x coordinate becomes smaller).

The detection means 12 that has started its operation roughly stores the initial value "o" in the B register *S5), and stores it in the X8C register as the scanning start coordinate Xst and the main scanning coordinate XSC (*S5).
6).

*After the processing of S1 to S6, the detection means 12 detects the scanning coordinate XSC
Read the image data at the pixel position specified by YSC and YSC from the image memory 30 (*S7), and check whether the pixel value of the read image data is a pixel value representing a character pixel (
In this embodiment, a check is made as to whether the pixel value is "1" (*S8). Depending on the result of the check at *S8, the detection means 12 operates as described in the following Φ to (2).

■When a character pixel is detected *If the pixel value of the image data read in by the check in S8 is the predetermined pixel value "1" representing a character pixel, it means that a character pixel has been detected on the scanning line, so the count value B is “1”
*S9), and then checks whether 8=1 (*510).

If 8=1 in the check in *S10, the detection means 12 sets the current scanning coordinate XSC to X as a candidate (Xc+candidate) for the starting end coordinate XCI of a predetermined character line. , writing of Xc+ candidate to be stored in register, *511), writing of XC+ candidate is not performed unless B=1. X only when B=1. By writing one candidate, the starting end coordinate
. 1 can be detected.

Next, the detection means 12 compares the count value B with an arbitrarily set threshold value BTHL (for example, BTHL = 3) (*512).

*As a result of the comparison in S12, B=8. , if L then BTHL
Character pixels that have been detected consecutively for a number of times are considered not as noise but as character lines constituting a character graphic pattern, and therefore represent that a predetermined character line has been detected. Therefore, the detection means 12 detects the main scanning coordinate Xsc'f and the scanning stop coordinate X of the character pixel detected BT)ILth among the continuously detected character pixels. and store it in the Xc register *513),
B indicates information “1” indicating that scanning is to be stopped. Store it in the register *314), then stop the operation (*εND
).

As a result of B=B, HL, X is stored in the XCI register. , the starting point coordinates XCI to be detected by the candidate.

If the comparison result in *S12 is not B"BTHL, the detection means 12 adds a constant value 0^DD to the main scanning coordinate Xsc in order to scan the image data of the next pixel on the scanning line *511), Scanning line - Coordinate Xsc and coordinate Xε are compared to determine whether scanning of the line has been completed (*S
16).

*If the result of the comparison in S16 is X sc> +1) 'i-scan Scanning stop coordinate X is increased and stored in the Xc register *513), information indicating that scanning has been stopped is stored in the roJ88u register *314), and the operation is stopped (*END).

*If the comparison result in S16 is not XSC>XE, the scanning line -
Since this indicates that the scanning of the line has not been completed, the process returns to *S7 to scan the image data of the next pixel.

■When a background pixel is detected *If the pixel value of the image data read in the check in S7 is not the predetermined pixel value "1" representing a character pixel, therefore, if the predetermined pixel value representing a background pixel is "0", Detection means 12
initializes the count value B and stores oJ in the B register as the count value *517), then performs *S15-16 and operates according to the comparison result of *S16. is assumed to represent a pixel having a predetermined pixel+a (density) representing a pixel forming a background pattern.

*By initializing the count value B in S17, the number of character pixels can be counted only when character pixels are detected consecutively.

The character line detection means 12 that operates as described above includes B, HL
-J, character pixels that are completely continuous are regarded as noise, character pixels that are continuous by at least BTHL are regarded as a predetermined character line that constitutes a character figure pattern, and the presence or absence of this predetermined character line and the starting end coordinate X are determined. , and detect. Therefore, for example, one isolated character pixel is ignored as noise, and the presence/absence information of a predetermined character line and the starting end coordinate XCI are used in the processing for detecting the first to fourth coordinates. The accuracy of coordinate detection can be improved. Furthermore, even in the case of a line with a small number of characters, the first to fourth coordinates can be detected with high accuracy.

In the second embodiment, when the number of consecutive scanning lines in which character pixels are detected is equal to or greater than a predetermined number, the control means 14 is set to the first, second,
The configuration is similar to that of the third embodiment except for the means for outputting the third and fourth coordinates. The second embodiment will be described below, but the explanation of the same components as in the first embodiment will be omitted, and only the points that are different from the second embodiment will be explained.

FIG. 5 is an operational flowchart for explaining the character line detection control means of the third embodiment. Note that the operations of S14 to S20 of the control means 14 of the second embodiment are similar to the operations of S814 to S20 of the first embodiment (see FIG. 3 (8)), so
14 to 20 are omitted from the drawing.

The control means 14 of the second embodiment has a T1 counter (
or a register).

As also shown in FIG. 5, the control means 14 of this embodiment includes:
In S2, the P register is initialized and the count value T1 is initialized (initial value "0").

Further, if it is found by the check in S7 that a predetermined character line has been detected, the control means 14 increments the count values T and V by ``1'' (hereinafter referred to as the scanning line where the character line was detected).
The number of character scanning lines (referred to as character scanning lines) is counted (S25).

Roughly speaking, when the control means 14 finds that P=1 by the check in S23, it stores information "○" indicating that no character line has been detected in the P register 16 (522), and then sets the count value T1 to any suitable value. The set threshold value T and □ are compared (S26).

As a result of the comparison in S26, if TI>TITHL, T1□
Assuming that the character lines on the consecutive character scanning lines exceeding HL are not noise, perform the processing in steps 323 and 24,
The count value T is initialized (S27).

Further, as a result of the comparison in S26, if TI>T11H5, the character lines on the character scanning lines that have been consecutively detected by the number of characters equal to or less than T, AHL are considered to be noise, and the processing in 823 to 24 is not performed. Initialize the count value T1 (S2
7).

By initializing the count value T1 in S27, the number of character scanning lines can be counted only when the character scanning lines are continuous.

After the process of S27, the control means 14 performs the process of S19 (see 9 in FIG. 3(B)).

In the second embodiment, it is possible to avoid a decrease in the detection accuracy of the coordinates YT, Y[l, XL, and XE when noise is detected as a character line, and improve the detection accuracy of these coordinates.

In the third embodiment, the control means 14 outputs the first, second, third, and fourth coordinates when a predetermined plurality of consecutive scanning lines in which no character pixels are detected are consecutive. In addition to using it as a means,
The configuration is similar to that of the first embodiment. The third embodiment will be described below, but the explanation of the same components as in the first embodiment will be omitted, and only the points that are different from the first embodiment will be explained.

FIG. 6 is an operational flowchart for explaining the character line detection control means of the third embodiment. Incidentally, the operations of S14 to S20 of the control means 14 of the third embodiment are similar to the operations of S314 to S20 of the first embodiment (see 9 in FIG. 3(B)).
14 to 20 are omitted from the drawing.

The control means 14 of the third embodiment includes a T2 counter (or register) for counting the number (count value) T2 of scanning lines in which no character line is detected.

As shown in FIG. 6, the control means 14 of this embodiment is
2, the P register 16 is initialized and the count value T2T is
Initialize HL (initial value "0").

Also, if it is found in the check in S7 that the scanning line-to-line scanning has been completed without detecting a predetermined character line,
The control means 14 sets T2 as
]” is incremented by 528), and its shun count value T
2 and an arbitrarily set threshold T2THL (S29).

As a result of the comparison in S29, if T2 > T2□1, the control means 14 considers that the consecutive background scanning lines exceeding T2 tsL% are scanning lines that scanned the blank area between the lines. A determination is made in S21, and processing is performed according to the result of this determination.

As a result of the comparison in S29, unless T 2 > T 2THL, the background scanning lines that are consecutive in number equal to or less than T2□H5 are considered to be the scanning lines that scanned the so-called white areas or blurred areas in the character line. , 319 is performed without performing the processes of 321 to 24 (see FIG. 3(B)). Therefore, if there is a white spot or blur in a character line (for example, multiple consecutive character scan lines, consecutive background scan lines with a number of T2□HL or less, and multiple consecutive character scan lines in sequence) Even if the next scanning line after the character scanning line is the background scanning line, it is possible to avoid erroneously outputting the coordinates Y□, Y8, XL, and XR.

Furthermore, when it is found that a character line has been detected by the check in step 87, the detection control means 14 initializes the count value T2% (
In S30), by initializing the count value T2 when a character line is detected, only the number of continuous background scanning lines can be counted.

In the third embodiment, it is possible to avoid a decrease in the detection accuracy of the coordinates YT, Y8, XL, and XR due to white spots or blurring in the character line, and to improve the detection accuracy of these coordinates.

Firstly, in the fourth embodiment, the character line detection device 10 determines the pixel@(density) of a pixel of image data by using the pixel values of an arbitrary suitable number of other pixels in the vicinity of the pixel. The configuration is similar to that of the first embodiment except that a filter is provided. below,
The fourth embodiment will be explained, but the explanation of the same components as in the first embodiment will be omitted, and the points different from the first embodiment will be explained.

In this embodiment, a filter is used to remove noise from the image data D, and is provided between the image memory 30 and the detection means 12, for example.

FIGS. 7(A) to 7(B) are explanatory diagrams of the filter, in which (A) is a functional block diagram showing an example of the configuration of the filter, and (B) is a diagram showing an example of the observation window of the filter. .

As shown in FIG. 7(A), the filter 34 included in the character line detection device 10 of this embodiment consists of a reading means 34a and a memory 34b, and has, for example, a 3×3 observation window. As shown in FIG. 7(B), this observation window is centered on the pixel (target pixel) u5 whose pixel value is to be determined, and
It has a configuration in which 9 pixels are arranged in 3 rows and 3 columns. The pixel value of the pixel of interest u5 is determined by determining the pixel value of the pixel u5 other than this pixel u5 (
Observation pixels) u+ to u4 and u6 to u9G are used. Note that the arrangement of the pixel of interest and the observation pixel is not limited to the illustrated example, and can be changed as desired.

The reading means 34a reads the scanning coordinate X5 from the detecting means 12.
If you input C1Y sc%, these coordinates X SC% Y
The pixel at the pixel position specified by 8C is taken as the pixel of interest U5, and the image data D of the pixel of interest U5 is read from the image memory 30. At the same time, the observed pixels U, ~u4 and The pixel position of these observed pixels read from the image data Du image memory 30 of u8 to U9 has a specific positional relationship with the pixel of interest u5, so it can be determined, for example, by calculation from the coordinates XSC, YSC. I can do it. Therefore, the reading means 34a has the coordinate X. ,Y.

By inputting , the image data C1 of the pixel of interest and the observed pixel can be read.

In this embodiment, for example, when the sum of the pixel values of pixels ul to u9 reaches or exceeds an arbitrarily suitable predetermined comparison value,
A filter logic is used that corrects the pixel value of the pixel of interest to a pixel value representing the character/figure pattern DI% and outputs it, and according to this filter logic, the scanning coordinates x,. , Ysc determines the pixel value of the image data D at the pixel position specified by Ysc. That is, in this embodiment, the pixel value of the pixel U5 is determined from the density distribution in the vicinity of the pixel of interest U.

The configuration of a filter having such filter logic can be any suitable configuration conventionally used in image processing, and is therefore not limited to what is described below. The configuration will be explained in detail.

In order to achieve the filter logic as described above, the reading means 34a reads pixels U, which are in a specific positional relationship as described above,
When the image data D of ~U is read from the image memory 30, the pixel values t1 to t9 of these pixels (pixel u1
The pixel value of u2 is t, the pixel value of u2 is t2,...
The pixel value of u9 is assumed to be t) is used as an address for reading the corrected pixel value (corrected pixel value) stored in the memory 34b. In this case, the reading means 34a outputs a nine-digit binary address expressed using pixel values t1 to t9 to the memory 34b.

Roughly, when the address from the reading means 34a is input, the memory 34b outputs the corrected pixel value of the pixel of interest u5 designated by this address. As a result, corrected image data D consisting of corrected pixel values is output from the memory 34b to the detection means 12.

To briefly explain, in the memory 34b, the pixel value (pixel value "1" in this embodiment) representing the character/figure pattern Dlu is stored in advance at the address indicated, and the background pattern D2 is stored at the address indicated. The pixel value (
In this embodiment, the pixel value "0") is stored in advance.

By the way, the character figure pattern D1 has a black bit (pixel value "1")
'') and background pattern D2 are expressed with white bits (pixel value "0"), the black bits in the background pattern D2 become noise, but in the case of (2) above, even if the pixel of interest U is black, Even if it is a bit, the memory 34b corrects the pixel value of the pixel of interest u5 to a white bit meaning the background pattern D27a and outputs it.

The value of the comparison value kf can be any suitable value, but
For example, when using a 3×3 observation window, kf=5 may be used. When a 3x3 observation window is used and kf=5, noise smaller than 2x2 bits can be removed.

In the fourth embodiment, the first to
Since the fourth coordinate is detected, the detection accuracy of these coordinates can be improved.

In addition, the character line detection device of the fourth embodiment! After the corrected image data D is input to the detection means 12 in step 10, the operation for detecting the line position performed by the detection means 12 and the control means 14 is performed in the same manner as in the first embodiment.

In this fourth embodiment, in addition to the above-described filter logic, when the sum of the pixel values of observed pixels U, ~u4, and u6 to u9 is greater than or equal to the comparison value kf, the pixel value of the pixel of interest is (regardless of the pixel value of) is corrected to a pixel value that means the character/figure pattern D1 and output, and along with this, the observed pixel U
It is also possible to use a logic that when the sum of the pixel values of 1 to u4 and U6 to u9 is smaller than the comparison value kf, the pixel value is corrected to indicate the background pattern D2 and output.

In addition, the character figure pattern D1 is used as the white bit and the background pattern D2.
When expressed as a black hit, as a filter logic,
When the sum of the pixel values of the pixel of interest U and the observed pixels U, ~tJ4, and ue~U9 is equal to or less than the comparison value, the pixel value of the pixel of interest is corrected to a pixel value representing the character/figure pattern D1 and output. At the same time, when the sum of pixel values becomes larger than the comparison value kf, the pixel value of the pixel of interest u5 is set to the background pattern D2.
It is also possible to use logic that corrects and outputs the pixel value to mean %.

Furthermore, in the above-described embodiment, when forming a specific pattern representing a pixel of interest or a character line, the pixel value of the pixel of interest is corrected to a pixel value representing the character figure pattern DI and then output, so that the pixel of interest forms a character line. The filter logic may be configured so that when the specific pattern D2 to be represented is not formed, the pixel value of the pixel of interest is corrected to a pixel value representing the background pattern and output. For example, when the filter has a 3x3 observation window as shown in FIG. "
1", and in cases other than (1) to (4), the pixel value of the pixel of interest u5 is set to a pixel value representing the background pattern, for example, "0".

(1) When at least the pixel values of pixels LJI, u5, and U9 are the pixel values representing a character/graphic pattern (2) When the pixel values of at least the pixels u2, u5, and u8 are the pixel values representing the character/graphic pattern (3) ) at least pixel u 3 ,
When the pixel values of u 5 and u 7 are pixel values representing a character/graphic pattern (4) When the pixel values of at least pixels u 8 , 'J 5 and u4 are pixel values representing a character/graphic pattern, this invention is as described above. The present invention is not limited to the examples, and therefore the configuration and operation of each component, the flow of the first signal for detecting the first to fourth coordinates, numerical conditions, and other conditions may be changed or modified in various ways. can be transformed.

For example, since the character line detection device operates in the main scanning direction (X-axis direction) or in the character line direction, the x-y coordinate system or the image data may be rotated, as is done in conventional image processing. For example, when expressing the direction of a character line by the amount of inclination of the character line, the x-y coordinate system or image data is
By rotating by 1, the main scanning direction can be set to the character line direction. The character line direction can be easily detected using conventionally proposed methods or devices.

Image data may be obtained by main-scanning a form, manuscript, etc. in the character line direction using a photoelectric conversion section, and this image data may be stored in an image memory.

In addition, in the above embodiment, the operation was explained with the character line direction being along the X-axis and the X-axis direction being the main scanning direction of image data in the X-Y coordinate system shown in FIG. The coordinates of the first detected character pixel may be detected with the ty-axis direction and the y-axis direction as the main scanning direction of the image data (for example, in the case of a vertically written document). The character line detection device when the y-axis direction is the main scanning direction of image data operates substantially in the same manner as in the embodiment described above,
Therefore, it can be easily constructed based on the embodiments described above.

Therefore, the character line detection bag M% is set so that the image data is main scanned in the X-axis direction or the y-axis direction in response to the input of the instruction signal to set the main scanning direction of the image data in the tx-axis direction or the y-axis direction. It can also be configured.

Further, the flow of operation of each component is not limited to the illustrated example and can be changed as desired.

(Effects of the Invention) As is clear from the above description, according to the character line detection device of the present invention, the first to
Detect the fourth coordinate. Therefore, by using these coordinates to define the area within the circumscribed frame as the line area, it is possible to obtain a line area with less margin than before, and this allows image processing such as character extraction within the character line area. When performing image processing, it is possible to improve the efficiency of image processing by avoiding scanning image data in extra blank areas.

Furthermore, since the detection processing of the first to fourth coordinates is simple, the device configuration can be simplified. Further, since it is not necessary to create a histogram for detecting the first to fourth coordinates as in the conventional method, the memory capacity for detecting these coordinates can be small, and the device configuration can be simplified. By simplifying the device configuration, it is possible to reduce the scale of the device and reduce the cost of souvenirs.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram for explaining the character line detection device of the first embodiment, Fig. 2 is a diagram for explaining image data, and Figs. 3 (A) and (B) are the characters of the first embodiment. Figure 4 provides an explanation of the operation of the line detection control means; Figure 4 provides an explanation of the operation of the character line detection means of the first embodiment; Figure 5 provides an explanation of the operation of the character line detection control means of the second embodiment. Figure 6 is a diagram for explaining the operation of the character line detection control means of the third embodiment, Figures 7 (A) and (B) are diagrams for explaining the filter of the fourth embodiment, and Figure 8 is a diagram for explaining the operation of the character line detection control means of the third embodiment. It is a figure used for explanation of conventional drawing. 10...Character line detection device, 12...Character line detection means 14...Character line detection control means 16...P register, 18...Y□ register 2
0...Y8 register, 22...XL register 26
...XR register, 34...filter. Patent applicant Oki Electric Industry Co., Ltd. Explanatory diagram of image data Figure 2 - Operation flow of the control means of the embodiment Figure 3 (B) Explanatory diagram of filter Figure 7 June 23, 1989

Claims (9)

[Claims] (1) In a character line detection device for detecting a character line area by scanning image data including character/figure patterns constituting a line, the image data is first detected by scanning the image data in one direction. character line detection means for detecting the coordinates of a character pixel and the coordinates of a character pixel detected first by scanning the image data in the other direction; When a character pixel is detected on the scanning line where the character pixel is detected, the scanning coordinates of the scanning line where the character pixel is detected are detected as the first coordinates for defining the circumscribing frame of the line, and the scanning coordinates of the scanning line where the character pixel is detected are When no character pixel is detected on the next scanning line, the scanning coordinates of the scanning line where the character pixel was detected are detected as second coordinates for defining the circumscribed frame, and from the first coordinate to the second coordinate. detecting the smallest coordinate among the coordinates of the character pixel detected on the scanning line between the first and second coordinates as the third coordinate for defining the circumscribing frame; a character line detection control means for detecting a maximum coordinate among the coordinates of the character pixel detected as a fourth coordinate for defining the circumscribed frame. (2) The character line detection device according to claim 1, wherein image data on a scanning line in which character pixels are detected by scanning in one direction is scanned in the other direction. (3) The character line detection device according to any one of claims 1 to 2, wherein the coordinates of a first detected character pixel among a plurality of consecutive character pixels of a predetermined number or more are detected. (4) The character line detection device according to any one of claims 1 to 3, wherein the character line detection means is a means for storing coordinates of the character pixels. (5) When a character pixel is not detected on a scanning line following the scanning line in which the character pixel was detected, first, second, third, and fourth coordinates are output. 4. The character line detection device according to any one of 4. (6) The first, second, third, and fourth coordinates are output when a predetermined number or more of consecutive scanning lines in which the character pixels are detected are output. The character line detection device according to item 1. (7) The first, second, third, and fourth coordinates are output when a predetermined number or more of consecutive scanning lines in which the character pixel is not detected are output. The character line detection device according to item (1). (8) Claim 1 characterized in that it comprises a filter that determines the pixel value of the pixel of the image data by using the pixel values of any suitable number of other pixels in the vicinity of the pixel.
8. The character line detection device according to any one of 7 to 7. (9) The character line detection device according to any one of claims 1 to 8, wherein the direction along the line is the main scanning direction of the image data.