JPS63284691A - Pattern recognizing device - Google Patents

Abstract

PURPOSE:To easily realize character input in a free direction by obtaining the difference in direction value between corresponding strokes of an input pattern and a standard pattern and evaluating its variance value. CONSTITUTION:A recognition data processing part 12 analyzes a sequence of coordinate values indicating the input pattern stored in a position data buffer 21 to obtain direction values indicating directions of written strokes. The sequence of these direction values is successively stored in a recognition data buffer 22 and is supplied to a recognition processing part 13. The recognition processing part 13 checks the number of direction values in this sequence and reads out sequences of direction values of a pertinent number of strokes from a recognition dictionary 31 in order. The difference in direction value between corresponding strokes of each standard pattern and the input pattern is obtained to obtain an average and a variance value sigma of differences in direction value of respective strokes. The standard pattern for which the variance value sigmais minimum is obtained as the recognition result of the input pattern.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention easily recognizes a pattern input by hand via a coordinate input device such as a tablet, regardless of the orientation of the pattern. This invention relates to a pattern recognition device that can perform

(Prior Art) With the development of information processing technology, various document creation devices have been developed. However, in most of these systems, character information (character code) is entered via a keyboard or the like, and the entered characters are sequentially displayed on a display according to a predetermined rule while creating a document. For this reason, for example, when changing the direction of an input character, an instruction to change the direction of the character is given by some editing operation after the character is input.

On the other hand, recently, attempts have been made to use a coordinate input device such as a tablet to input a character pattern written on the tablet surface as a series of coordinate values, analyze this, and input characters. In other words, the characteristics of a handwritten pattern are determined by analyzing the input coordinate value series, the input pattern is recognized by comparing it with the characteristics of standard patterns registered in advance in a recognition dictionary, and the recognition results are input as characters. It has become.

According to such a character input device that uses the so-called online handwritten character recognition method, it is possible to create a document while inputting characters as if writing on a paper, compared to creating a document by inputting characters using a keyboard as described above. It has the advantage of being very easy to handle and operate.

However, there are various problems when extracting features of an input pattern by analyzing a series of input coordinate values and performing pattern recognition by comparing with features of a standard pattern. For example, due to recognition accuracy issues, it is necessary to specify the direction and size of the character in advance, and then input the character pattern by hand so that the conditions are met. Therefore, when changing the orientation of characters, it is necessary to specify the orientation each time, which is a very troublesome operation.

In order to solve this problem, it has been considered to prepare multiple types of standard patterns with different orientations and perform recognition processing on input patterns for each orientation.
There were problems in that the scale of the device configuration was too small, and the recognition processing became unnecessarily complicated, resulting in a reduction in recognition accuracy.

(Problems to be Solved by the Invention) As described above, with conventional devices, when it is desired to change the direction of characters in a created document, it is difficult to specify the direction of the characters, which requires a cumbersome operation, and it is difficult to change the direction of the characters in any direction. There was a problem in that attempting to input characters would make the device complicated.

The present invention has been made in consideration of these circumstances, and its purpose is to provide a simple structure that can easily realize character input in any direction via a coordinate input device such as a tablet. An object of the present invention is to provide a highly practical pattern recognition device.

[Structure of the Invention] (Means for Solving the Problems) The present invention analyzes a series of coordinate values sequentially input through a coordinate input device such as a tablet that inputs coordinate values corresponding to a designated position. , obtain a direction value indicating the direction of the stroke of the pattern written and input into the coordinate input device, for example, as a value obtained by quantizing the direction of the stroke, and combine it with the series of direction values of the standard pattern registered in advance in the recognition dictionary and the above input. The input pattern is recognized by determining the difference in the direction value for each corresponding stroke between the series of direction values of the pattern and determining the variance value of the difference in these direction values. It is something.

Also, the direction of the input pattern is determined from the difference in the above direction values.

(Operation) According to the present invention, the series of direction values of an input pattern and the series of direction values of a standard pattern are not simply compared, but the difference in direction values is calculated for each corresponding stroke. The variance value is evaluated. Therefore, if the input pattern and the standard pattern are equal, the difference in direction values between their corresponding strokes will exhibit a constant value, and the variance value will be the minimum. In other words, the difference in each direction value between the corresponding strokes between the input pattern and the standard pattern shows a value that depends on the difference in the orientation of the pattern, and the variance value does not change due to the difference in the orientation of the pattern.

Therefore, by evaluating the variance value and recognizing the input pattern, it is possible to effectively obtain the recognition result regardless of the orientation of the input pattern.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a character input device realized by incorporating the embodiment device, in which 1 is a coordinate input device consisting of a transparent tablet, etc., 2 is a control device which is the main body of the device, and 3 is a character input device from a liquid crystal display, etc. This is a display device.

This device includes, for example, a coordinate input device 1 as shown in FIG.
It has a structure in which the display device 3 and the display device 3 are laminated and integrated, and this is mounted on the device main body 2. The transparent tablet serving as the coordinate input device 1 detects and inputs information on a position indicated with a pen or the like as coordinate values on the tablet surface. The liquid crystal display serving as the display device 3 has a display surface having the same dimensions and the same coordinates as the tablet surface, and the displayed information can be visually recognized through the transparent tablet. When the transparent tablet is instructed to display the display information, information on the indicated position is inputted via the tablet, and the display information can be specified by the control device 2 as described later. .

Now, as shown in FIG. 1, the control device 2 includes an input section 11.
Recognition data processing unit 12. An arithmetic processing execution section consisting of a recognition processing section 131, a display data processing section 141, a display section 15, and a position data buffer 21. It is comprised of a buffer memory consisting of a recognition data buffer 222, a display data buffer 231, a character data buffer 24, and a dictionary memory consisting of a character recognition dictionary 311 and a character pattern dictionary 32.

The input unit 11 inputs and processes coordinate values input from the coordinate input device 1, and sequentially stores a series of the coordinate values in the position data buffer 21. Further, when the display device 3 is displaying an icon for inputting various control commands, the input unit 11 determines whether or not the input coordinate values indicate the icon, and the input unit 11 determines whether the input coordinate values indicate the icon. If so, each operation of the arithmetic processing section described above is activated in accordance with the input control command.

The recognition data processing section 12 analyzes the series of coordinate values indicating the input pattern stored in the position data buffer 21 as described above, and obtains the direction value indicating the direction of the writing stroke.

Calculation of the direction value of the stroke by analyzing this coordinate value series involves, for example, finding the direction of change from the first coordinate value of the input pattern to the next coordinate value, and then determining the direction by quantizing it, for example, as shown in Figure 3. This is done by determining which direction value corresponds to the specified direction value. Then, the series of direction values obtained up to the end point coordinates of the input pattern is compressed, for example, data is compressed by grouping consecutive same direction values together, and the series of direction values that are finally left is used for the stroke forming the input pattern. This is done by creating a direction value series. In other words, each time the direction value changes, the direction value is sequentially extracted as information indicating the direction of the stroke.

As a result, when an input pattern of "3" as shown in FIG. 4(a) is given, the series of direction values of the input pattern is r2, 5, 2 as shown in FIG. 4(b). ，
3, 5, 7 J.

Note that if the input pattern is given horizontally to the left, the sequence of direction values will be determined as rO, 3, 0, 1, 3, 5J.

The sequence of direction values obtained by the recognition data processing section 12 in this manner is sequentially stored in the recognition data buffer 22 and subjected to pattern recognition processing by the recognition processing section 13.

The recognition processing unit 13 then converts the direction value series of the input pattern stored in the recognition data buffer 22 to the direction value series of the standard pattern registered in advance in the character recognition dictionary 31 in the following manner. Recognizes and processes input patterns.

That is, in the character recognition dictionary 3■, for example, as shown in FIG. 5, standard pattern information associates character codes (standard pattern categories) with their direction value series, They are classified and registered in advance according to the number of direction values forming a series.

When a direction value series related to one input pattern is stored in the recognition data buffer 22, the recognition processing unit 13 checks the number of direction values forming the direction value series and stores it in the recognition dictionary 31.
The direction value sequence of the corresponding number of strokes is read out in sequence. Then, the difference in direction value is calculated for each corresponding stroke between the standard pattern and the input pattern.

Specifically, as mentioned above, when the direction value of the i-th stroke of the input pattern that is quantized in eight directions is A, and the direction l value of the first stroke of the standard pattern is B, the direction value is The difference C1 is C,=A,
-B, (mod 8) j-1, 2, 3, ~
, n.

For example, the recognition processing unit 13 calculates the average of the differences in the direction values of each stroke as described above, and calculates the variance value σ.

The above process is sequentially executed for standard patterns having the same number of strokes as the input pattern registered in the character recognition dictionary 31, and the standard pattern with the smallest variance value σ is obtained as the recognition result for the input pattern.

At this time, a standard pattern whose variance value σ is smaller than a predetermined value may be determined as a next candidate for recognition, so that the correct recognition result can be selected.

The information (character code) of the input pattern recognized in this way is sequentially stored in the character data buffer 24.

Furthermore, the display data processing section 14 determines the direction of the input pattern recognized as described above from the difference in the direction values. In other words, the inclination of the input pattern with respect to the standard pattern is determined from the difference in direction values, and this is determined as the writing direction of the input pattern.

The display unit 15 then obtains the standard pattern of the corresponding character from the character pattern dictionary 32 according to the character code obtained as described above. Then, this standard pattern is subjected to processing such as enlargement, reduction, rotation, etc. according to the input position and orientation information of the input pattern, and the character pattern is developed at a position on the display data buffer 23 corresponding to the pattern input position. . By developing the character pattern onto the display data buffer 24, the character pattern is displayed at the corresponding display position on the display device 3.

FIG. 6 shows the overall flow of processing procedures in this apparatus configured as described above.

To briefly explain this processing procedure, when the device is started up, initialization such as clearing the buffer memory is first performed (step a).

After that, the pen and the position input device (tablet) 1 are
The on state is checked (step b), and the coordinate values input when the pen is turned on are stored in the position data buffer 21 as character pattern data (step C). This process is repeated until a transition from pen-on to pen-off state is detected and the end of one character data input is detected (step e). When pen-off is detected, the information is stored as delimiter data for the input coordinate value (step d), and the process moves to the next step.

Thereafter, the size of the input character and its input position are determined from the series of coordinate values determined as described above (step f). This process is performed by determining the circumscribing frame of the input pattern indicated by the coordinate value series as the character size, and detecting the center coordinates of the circumscribing frame as the character input position.

Thereafter, step g) executes the above-mentioned turn recognition process based on the input coordinate value series, step h) outputs the recognition results such as character code and character orientation information to the display unit 15, and step h). Display the corresponding characters by (
Step i).

Here, the character recognition process shown in step g above is performed, for example, as shown in FIG. 7, starting with the process of obtaining a direction value sequence indicating stroke information of an input pattern (character) (step A).

Then, as described above, find a direction value string of characters (standard pattern) with the same number of direction values in the direction value string (step B), calculate the difference in direction values between corresponding points (strokes), respectively (step C), The variance value of the difference is calculated (step D). This processing procedure is repeatedly executed for all characters (standard pattern) having the same number of strokes as the input stroke (step E). Thereafter, the variance values determined for each character are compared with each other (Step G), and the character with the smallest variance value is taken as the recognition result for the cut turn (Step G).

Through the above processing procedure, the character pattern written via the coordinate input device 1 is recognized and inputted. This character input is repeated to create a document.

In this manner, the present device recognizes the input pattern by evaluating the variance value of the difference between the direction value series.

According to such a recognition algorithm, since pattern information is represented as a series of direction values, recognition processing can be performed regardless of the size of the input pattern. Furthermore, if the comparison patterns are the same, the difference in direction values found for each corresponding stroke will show a constant value that depends only on the inclination between the patterns. In other words, the differences in direction values found for each corresponding stroke are equal. Therefore, when the patterns are equal, the variance value of the difference in direction values is always the minimum regardless of the orientation of the patterns, and pattern recognition is therefore possible regardless of the orientation of the input pattern.

Moreover, as mentioned above, pattern recognition processing can be performed using a very simple processing procedure, and there are no problems associated with conventional methods such as an enormous amount of required capacity for recognition dictionaries, which has many practical problems. The effect is produced.

Note that the present invention is not limited to the embodiments described above. For example, the quantization number of direction values may be determined according to the specifications of the device. Further, in the embodiment, the variance value is calculated using the average value of the difference between the direction values, but the variance value may be calculated using the mode instead of the average value. In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As explained above, according to the present invention, a pattern input by hand in any direction and size using a coordinate input device such as a tablet can be processed by a very simple processing procedure. It can be recognized with high accuracy. Therefore, a great practical effect can be achieved as a character input device in a document creation device.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, in which Fig. 1 is a schematic configuration diagram of a character input device constructed by incorporating the embodiment device, and Fig. 2 is a diagram schematically showing the structure of the device. FIG. 3 is a diagram showing an example of quantized direction values, FIG. 4 is a diagram showing an example of a pattern and its stroke direction value sequence, FIG. 5 is a diagram showing an example of the configuration of a recognition dictionary, and FIG. FIG. 7 is a diagram showing the flow of the overall processing procedure of the embodiment device, and FIG. 7 is a diagram showing the flow of the recognition processing procedure. DESCRIPTION OF SYMBOLS 1... Coordinate input device (transparent tablet), 2... Control device (device body), 3... Display device (liquid crystal display), 11... Input section, 12... Recognition data processing section, 13... Recognition processing unit, 14... Display data processing unit, 15... Display unit, 21... Position data buffer, 22... Recognition data buffer, 23... Display data buffer, 24...・Character data buffer, 31...
・Character recognition dictionary, 32...Character pattern dictionary. Applicant's agent Patent attorney Takehiko Suzue-17= Figure 1 4J Figure 3 Figure 4 Figure 6 Figure 7

Claims (3)

[Claims] (1) A coordinate input device that inputs coordinate values corresponding to the indicated position, and a stroke of the pattern written and input to the coordinate input device by analyzing a series of coordinate values input sequentially through this coordinate input device. means for obtaining a direction value indicating the direction; a recognition dictionary in which a standard pattern is registered in advance as a series of direction values; and a direction value between corresponding strokes between the standard pattern registered in the recognition dictionary and the input pattern. and a means for determining a variance value of the difference in direction values, and a means for determining a standard pattern in which the variance value is smaller than a predetermined value as a recognition result for the input pattern. recognition device. (2) The pattern recognition device according to claim 1, wherein the direction value is given by quantizing the direction of the stroke. (3) The pattern recognition device according to claim 1, wherein the difference in direction values is used as information for determining the direction of the input pattern.