JPH09265345A - Stroke information encoding system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zone encoding system capable of shortening code data and suppressing the communication or storage cost of the code data further in the zone encoding system for sampling handwritten plotting information and compressing the coordinate information. SOLUTION: For a certain sampling coordinate (defined as a coordinate hereafter), in the case that the coordinate for which encoding is performed nearby and a plotting area are overlapped even partially, encoding is not performed. That is, for the coordinate of I=3, since the coordinate of I=2 and the plotting area are overlapped, encoding is not performed. For the coordinate I=4, since it is not overlapped with the coordinate of I=2 for which encoding is performed nearby, encoding is performed. At the time of encoding the coordinate of I=4, encoding is performed with the coordinate of I=2 as a relative origin. Also, the case of performing encoding by a zone division method for which a zone area is enlarged and the case for performing encoding by the zone division method for which one intra-zone address is made to correspond to plural picture elements are present.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoding method for compressing stroke information, and can be used in a handwritten drawing information processing terminal.

[0002]

2. Description of the Related Art As a coding method for sampling stroke information and compressing the information, a zone coding method (see:
Recommendation JT-T150) is known. The handwritten information is characterized in that the sampling is in a relatively narrow range when writing a character, and the range of one stroke is large when a map or a graphic is drawn, but the change in angle is small.

The zone coding method is a predictive coding method focusing on the characteristics of these handwritten information. That is, in the zone encoding method, a coordinate plane having a sampling position (0, 0) at a certain time point is set as shown in FIG. Then, this coordinate plane is divided into four quadrants of θ = 1 to 4, and the number of each quadrant is set as a quadrant number. Here, the origin, the X axis in the plus direction, and the Y axis in the plus direction belong to the first quadrant. The Y axis in the negative direction belongs to the fourth quadrant, and the X axis in the negative direction belongs to the second quadrant.

Each quadrant is divided into zones as shown by the solid line in FIG. 2, and each zone is given a zone number as shown in FIG. Further, each zone is divided into in-zone coordinate values (in-zone addresses) as indicated by the broken line in FIG. Here, the zone area is usually divided into 10 zones as shown in FIG. 2, and the zone area has a size of 16 pixels × 16 pixels.

By doing so, a certain sampling coordinate is a quadrant number difference which is the difference between the quadrant number of the sampling coordinate and the quadrant number of the sampling coordinate immediately before it.
It is possible to use only three pieces of coordinate information, that is, a zone number difference that is a difference between the zone number of the sampling coordinate and the zone number of the sampling coordinate immediately before it, and an address within the quadrant number of the sampling coordinate (intra-zone address). it can. The quadrant number and zone number of the stroke start coordinate (first sampling coordinate) are 1. Further, the in-zone address indicates a position in a certain zone, and is indicated by an address in the X axis direction and an address in the Y axis direction.

For example, assuming that the quadrant number of the second sampling coordinate is 3 and the zone number is 4, the quadrant number difference of the second sampling coordinate is the quadrant number 3 of the second sampling coordinate and the quadrant number of the first sampling coordinate. It becomes the difference from 1 and becomes 2. Similarly, the zone number difference is 3, which is the difference between the zone number 4 of the second sampling coordinate and the quadrant number 1 of the first sampling coordinate.

Here, the quadrant number difference and the zone number difference are encoded by a combination of the quadrant number difference and the zone number difference in order to compress the code. That is, encoding is performed using the zone code table shown in FIG. The zone code table defines the relationship between the combination of the quadrant number difference and the zone number difference and the code. In this zone code table, by utilizing the characteristics of the above-mentioned handwritten information, the one having a higher appearance frequency is assigned the one having a small number of bits. If the next sampling coordinate is not within the zone area or if the difference between the sampling coordinates does not exist in FIG. 3, the absolute coordinates are encoded as they are. However, the stroke start coordinates are encoded as they are without changing the quadrants and the zones.

In addition, in the zone coding method, the coding of the sampling coordinates of interest is performed by using a certain sampling coordinate (Xi-1, Yi-1) and a next sampling coordinate (Xi-1).
If the difference from (i, Yi) is (0, 0), it is not performed. Further, when the difference between the X component and the Y component between a certain sampling coordinate and the next sampling coordinate is 1 or less, it is said that the coding may not be performed. That is, the difference between one sampling coordinate and the next sampling coordinate is
Xi- (Xi-1) | ≤1, and | Yi- (Yi-
1) If | ≦ 1, it is not necessary to encode.

[0009]

However, even if the above conditions are satisfied, if the drawing areas (pen areas) of adjacent sampling coordinates overlap with each other due to the large line width, they overlap. By doing so, even unnecessary sampling coordinates are encoded, and the code data increases. That is, when the thickness of the line displayed on the display screen can be selected from a plurality of types, if a thick line width is selected, the drawing areas of the sampling coordinates may overlap. In this case, the sampling The coordinates are unnecessary for decoding.

When the sampling speed is low or the stroke speed is high, the difference between the sampling coordinates is often large. Especially when the line width is thick,
Since large characters or large figures are often drawn, the stroke speed also increases, and the difference between the sampling coordinates often increases. In such cases, each sampling coordinate is often outside the zone area,
When these are encoded, the code data will increase. That is, when the difference between the sampling coordinates is large, the next sampling coordinate does not correspond to one of the zone areas shown in FIG. 2 and therefore is outside the zone area, or if the zone area is 16 pixels × 16 pixels or more. Even if more than 10 zones are provided, even if the next sampling coordinate is in the zone area, it often does not correspond to the code number in zone code table 3, so the absolute coordinates are encoded as they are. Will be
The code data becomes long.

Therefore, the present invention has been made in view of the above, and provides a coding method capable of shortening code data and further suppressing communication or storage cost of code data. To do.

[0012]

The present invention was created to solve the above problems. First, stroke information encoding for sampling handwritten drawing information and compressing its coordinate information is described. In the method, it is characterized in that, with respect to a certain sampling coordinate, whether or not to encode the certain sampling coordinate is determined based on the relationship with the sampling coordinate serving as a relative origin. In the stroke information encoding method of the first configuration, it is determined whether or not the sampling coordinates are to be encoded, and if the encoding is not necessary, the encoding is not performed. Can be prevented, and the code data can be shortened.

Secondly, when it is determined whether or not the sampling coordinates are to be coded, the sampling which has been most recently coded between the drawing area of the certain sampling coordinates and the sampling coordinates serving as the relative origin. It is characterized in that the coding of a certain sampling coordinate is omitted when the drawing area of the coordinate partially overlaps. In the stroke information encoding method of the second configuration, since the encoding is not performed when the drawing area even partially overlaps the sampling coordinate that has been encoded most recently, the encoded data can be shortened. At the same time, encoding of sampling coordinates where drawing regions overlap is omitted, so that there is almost no problem in decoding. Thirdly, when determining whether or not to code the sampling coordinates, the drawing area of the sampling coordinates described above and the sampling coordinates most recently coded with the sampling coordinates serving as the relative origin are drawn. When the distance to the area is within a certain distance, the encoding of certain sampling coordinates is omitted.
In the stroke information encoding method of the third configuration, if the distance between the most recently encoded sampling coordinate and the drawing area is within a certain distance, encoding is not performed, so the encoded data is shortened. In addition, the coding of sampling coordinates within a certain distance is omitted, and there is almost no hindrance in decoding.

Fourthly, in a stroke information encoding system for sampling handwritten drawing information and compressing the coordinate information thereof, at least one sampling coordinate in a plurality of sampling coordinates where at least a part of a drawing area overlaps. Is characterized by omitting the encoding.
In the stroke information encoding method of the fourth configuration, encoding of sampling coordinates is omitted in a plurality of sampling coordinates where drawing regions partially overlap,
The code data can be shortened.

Fifth, when the encoding of the sampling coordinates is omitted, the sampling coordinates of which the encoding is omitted are selected so that the characteristics of the drawing input by handwriting can be expressed. . In the stroke information coding method of the fifth configuration, the coding of sampling coordinates is omitted so that the drawing characteristics can be expressed, and therefore the handwritten input drawing can also be expressed in the decoding. . Further, sixthly, in a plurality of sampling coordinates in which the drawing areas overlap each other, for each sampling coordinate, a vector connecting the sampling coordinate and a sampling coordinate immediately before the sampling coordinate, and a vector next to the sampling coordinate and the sampling coordinate It is characterized in that an angle formed by a vector connecting the sampling coordinates is calculated, and encoding of the sampling coordinates having a small angle is omitted. In the stroke information encoding method of the sixth configuration, in the sampling coordinates where the drawing areas overlap, the encoding of the sampling coordinates having a small degree of bending is omitted, so the sampling coordinates having a large degree of bending are encoded. The characteristics of drawing can be retained.

Seventh, in the stroke information coding system for sampling handwritten drawing information and compressing the coordinate information, a zone division method according to the characteristics of the inputted drawing information is applied and coded. It is characterized by performing. According to the stroke information encoding method of the seventh configuration, the zone division method according to the characteristics of the input drawing information is applied, so that the code data can be shortened.

Eighth, in the stroke information encoding method for sampling the handwritten drawing information and compressing the coordinate information thereof, in at least one zone division method, the X direction and Y in the zone having the smallest number of pixels.
The number of pixels in at least one of the directions is 4 or more. In the stroke information encoding method of the eighth configuration, the number of pixels in the X direction and Y direction of the zone having the smallest number of pixels is normally 2 pixels, but since it is 4 pixels or more, the sampling coordinates are set in the zone area. There is a high possibility that it will enter, and code data will not become long outside the zone area. Ninth, a plurality of zone division methods having different sizes of zone areas are provided, and according to the distance between the sampling coordinates of the encoding target and the sampling coordinates of the relative origin in the input drawing information. A zone division method is selected from the plurality of zone division methods and applied. In the stroke information coding method of the ninth configuration, since the zone division method in which the size of the zone area is different according to the distance between the sampling coordinates is applied, the zone division method suitable for the distance should be applied. By this, the coded data can be shortened without the sampling coordinates being outside the zone area. Further, tenthly, in the inputted drawing information, as the distance between the sampling coordinate to be encoded and the sampling coordinate serving as the relative origin becomes larger, a zone division method of applying a larger zone area is applied. To do. In the stroke information encoding method of the tenth configuration, the larger the distance between the sampling coordinates is,
Since the method of dividing a zone with a large zone area is applied, the coded data can be shortened without the sampling coordinates being outside the zone area.

Eleventhly, a plurality of zone dividing methods having different sizes of zone areas are provided, and the zone dividing method is selected from the plurality of zone dividing methods according to the line width of input drawing information. And then applied.
In the stroke information encoding method of the eleventh configuration, since the zone division method in which the size of the zone area is different according to the line width of the input drawing information is applied, a zone division method suitable for the distance is selected. By applying this, the coded data can be shortened without the sampling coordinates being outside the zone area. The twelfth feature is that the zone division method in which the zone area is larger as the line width of the input drawing information is larger is applied. This twelfth
In the stroke information encoding method with the configuration described above, the zone division method in which the zone area is larger is applied as the line width of the input drawing information is larger, so the code data can be shortened without being outside the zone area. it can.

The thirteenth method is provided with a plurality of zone division methods in which the size of the zone area is different in the X direction, and the sampling coordinates of the encoding target and the sampling coordinates of the relative origin in the input drawing information are provided. It is characterized in that a zone division method is selected and applied from the plurality of zone division methods according to the distance in the X direction between them. This thirteenth
In the stroke information encoding method having the above configuration, since the zone division method in which the size of the zone area is different according to the distance in the X direction between the sampling coordinates is applied, a zone division method suitable for the distance in the X direction is used. By applying this, the coded data can be shortened without the sampling coordinates being outside the zone area. In addition, fourteenth, a plurality of zone division methods in which the size of the zone area in the Y direction is different are provided, and the Y between the sampling coordinate of the encoding target and the sampling coordinate serving as the relative origin in the input drawing information is provided. It is characterized in that a zone division method is selected and applied from the plurality of zone division methods according to the distance in the direction. In the stroke information encoding method of the fourteenth structure, since the zone division method in which the size of the zone area is different according to the distance in the Y direction between the sampling coordinates is applied, the zone suitable for the distance in the Y direction is applied. By applying the division method, the coded data can be shortened without the sampling coordinates being outside the zone area.

Fifteenth, in the stroke information encoding system for sampling the handwritten drawing information and compressing the coordinate information thereof, the unit of the in-zone address in which one in-zone address is associated with a plurality of pixels. It is characterized by applying the zone division method that it has. In the stroke information encoding system of the fifteenth configuration, since one zone address is associated with a plurality of pixels, the coded data of the zone address does not become long while the sampling coordinates are within the zone area. The code data can be shortened.

Sixteenth, there are provided a plurality of zone division methods having different numbers of pixels corresponding to the in-zone addresses, and the zone division methods are divided according to the line width of input drawing information. It is characterized by selecting and applying a method. In the stroke information encoding method of the sixteenth structure, a plurality of zone division methods having different numbers of pixels corresponding to the in-zone addresses are provided, and the zone division method is selected and applied according to the line width. Since the coded data of the in-zone address does not become long while the sampling coordinates are within the zone area according to the width, the coded data can be shortened as a whole. The seventeenth feature is that a zone division method in which the number of pixels corresponding to one in-zone address increases in the drawing information to be input is applied is applied. In the stroke information encoding method of the seventeenth configuration, the larger the line width, the larger the number of pixels corresponding to one in-zone address in the selected zone division method. Since the code data of the in-zone address does not become long, the code data can be shortened as a whole.

[0022]

Embodiments of the present invention will be described with reference to the drawings. A handwriting input device A to which the stroke information encoding method of the present embodiment is applied is configured as shown in FIG. 4, and has an input unit 10, a display unit 20, an encoding unit 30, and a storage unit 40.
And a main control unit 50.

Here, the input unit 10 is for inputting handwritten drawing information, and more specifically, it corresponds to a digitizer. The display unit 20 displays a drawing display area and icons, and also displays handwritten information input by the input unit 10 and a message from the main control unit 50. Here, the icon is for designating attributes such as line width, color, writing, and erasing. This display unit 20 is specifically L
I have a CD. The encoding unit 30 encodes the input handwritten drawing information and decodes the encoded information. Further, the storage unit 40 stores various information for operating the handwriting input device A and coded code information. Further, the main control unit 50 controls the operation of each of the above-mentioned units as a program.

The operation of the handwriting input device A having the above configuration will be described. First, the general operation status will be described. In the encoding process, first, when an input operation is performed by the input unit 10 using an attached pen or the like, the input unit 10
In, the handwritten input information input is sampled at a constant cycle, and continuous drawing information becomes information of discrete sampling coordinates. Then, the information on the sampling coordinates is sent to the main control unit 50.

In the main control unit 50, whether the information input by the input unit 10 is input to the drawing display area or the display unit 20.
It is determined whether the input is to the icon displayed in. If the result of the determination is input to the drawing display area, the information of the sampling coordinates is sent to the display unit 20 and the encoding unit 30. If the input is to an icon, the main control unit 50
The content is converted into attribute information, the attribute information is sent to the encoding unit 30, the information on the display content corresponding to the input of the icon is read from the storage unit 40, and the information is output to the display unit 20.

Then, in the case of input to the drawing display area,
When the pen is separated from the input unit 10 after the input of the drawing information for one stroke is completed, the pen lift-up information is sent to the display unit 20 and the encoding unit 30. Then, in the display unit 20, in order to convert the received discrete sampling coordinates into continuous information, data interpolation between the sampling coordinates is performed, and continuous drawing information after interpolation is displayed.
At the time of this display, the display is performed according to the above attribute information. For example, if the attribute information is written, the drawing position is colored, while if the attribute information is erased, the drawing position is displayed without coloring.

Further, an icon is input by the input unit 10, and information on display contents corresponding to the icon is displayed on the display unit 20.
When the information is sent to, the information is displayed on the display unit 20. Further, in the encoding unit 30, when the sampling coordinates and the attribute information are sent, they are sequentially encoded to generate code data. Then, when the code data is stored, the code data is sent to the storage unit 40 and stored.

On the other hand, in the decoding process, the coded data is sent to the coding unit 30. That is, when the code data is stored in the storage unit 40, the code data is sent from the storage unit 40, and when the code data is sent through a transmission line (not shown),
It is sent from the transmission line. Then, in the encoding unit 30, the input code data is decoded into sampling coordinates or attribute information and sent to the display unit 20. Display 2
At 0, display is performed as in the case of the above-mentioned encoding processing.

The main controller 50 controls the series of processes described above. For example, various controls such as bus control, instruction to start encoding / decoding processing, instruction to read / write stored information, instruction to display various messages are performed.

Next, a specific operation of the above-mentioned encoding unit 30 and the like will be described. The encoding process and the decoding process in the first embodiment will be described. First, the encoding process will be described with reference to the schematic flow chart of FIG. Here, FIG.
The case where the drawing shown in FIG. In FIG. 5, it is assumed that the line width is 5 × 5 pixels.

In step 101 (hereinafter step is referred to as S), it is analyzed whether the input data is sampling coordinates, attribute information, or pen lift-up information. This analysis is performed by the main control unit 50, and which of the above information can be determined by the information from the input unit 10.

If the analyzed data is attribute data, the process proceeds to S102, and if the analyzed coordinates are sampling coordinates, S103.
If the information is pen lift-up information, the process proceeds to S107. Note that the attribute information is in one drawing information (I in the case of FIG. 5).
(From 1 to I = 4) is not entered. That is, the starting point sampling coordinates, the ending point sampling coordinates, and the pen lift-up information of the drawing information are continuously input. The following processing is performed by the encoding unit 30. In S102, the code data defined for each attribute is assigned to the input attribute information, and the attribute code data is generated. Here, the attribute code data has a fixed length of 16 bits. In S103, the counter is used to detect whether the sampling coordinates are the first sampling coordinates (starting point sampling coordinates) or other sampling coordinates. If the sampling coordinates are the first sampling coordinates, the process proceeds to S104, and if the sampling coordinates are other than that, the process proceeds to S105. To do.

At S104, since the first sampling coordinate does not take the difference, the input coordinate value (absolute coordinate) is encoded as it is. The bit length at that time is determined by the resolution of the input unit 1. For example, the resolution is 2 as shown in FIG.
If it is 56 pixels × 256 pixels, the code bit length is represented by 8 bits for both the X coordinate and the Y coordinate. That is, the first sampling coordinate in FIG.
0), the sign of the first sampling coordinate is
(0000101000001010).

In step S105, the drawing area of the I-th sampling coordinate (I is a positive number from 2 to N), which is the target for determining whether or not to encode, and the drawing area of the most recently encoded sampling coordinate are overlapped. Detect whether or not
For example, when the sampling coordinate before the target sampling coordinate (which is referred to as the previous sampling coordinate) is encoded, it is determined whether the drawing area of the previous sampling coordinate and the drawing area of the target sampling coordinate overlap each other. To detect. Here, whether or not the drawing areas overlap each other is determined by detecting the difference between the target sampling coordinate and the most recently encoded sampling coordinate and the line width. If the drawing areas partially overlap each other, they are considered to overlap. Then, if they overlap, the coordinates are directly encoded without encoding.
If it does not overlap, the process proceeds to S106.

For example, for the second sampling coordinates in FIG. 5, the first and second sampling coordinates are (1
0, 10) and (16, 13), and since the drawing areas of these are not overlapping, the process proceeds to step S106, and the second sampling coordinates are encoded. As for the third sampling coordinate, the third sampling coordinate is (18, 14), and the drawing area of the second sampling coordinate and the drawing area of the third sampling coordinate overlap each other, so the third sampling coordinate is encoded. S10 without
Move to 1. Further, since the drawing area of the fourth sampling coordinate does not overlap with the second sampling coordinate which has been most recently encoded, the process proceeds to S106 and is encoded.

In S106, the I-th sampling coordinate (I is a positive number from 2 to N) to be encoded is encoded. Here, encoding is performed by the difference between the I-th sampling coordinate and the most recently encoded sampling coordinate.

This encoding process will be described more specifically. In this encoding process, the zone code data obtained by performing the variable length encoding process on the relationship between the I-th sampling coordinate to be encoded and the sampling coordinate most recently encoded. And the address code data in the zone are added together.

For example, the encoding of the second sampling coordinates in FIG. 5 will be described. The first sampling coordinates are relative origins, and the second sampling coordinates are (6, 6) when viewed from the first sampling coordinates as the relative origins.
3). That is, it can be seen from FIG. 1 that the second sampling coordinates are in the first quadrant when viewed from the relative origin,
The quadrant number is 1. The zone number is 5 from Fig. 2.
It turns out that. Since the quadrant number of the first sampling coordinate is 1 and the zone number is 1, the quadrant number difference is 0.
Then, the zone number difference is 4, and therefore the zone code of the second sampling coordinate is (100010) from FIG. Since the code length of the in-zone address is the minimum number of bits that can represent the maximum value of the in-zone address, the in-zone address is (2,
The in-zone address code of the second sampling coordinate which is 3) is (1011). Therefore, the code data of the second sampling coordinates are obtained by adding these (10001
01011).

Regarding the fourth sampling coordinate,
Since the most recently encoded sampling coordinate is the second sampling coordinate, this second sampling is the relative origin, and the fourth sampling coordinate is (6, 3) when viewed from the second sampling coordinate as this relative origin. . In other words, the fourth sampling coordinates, when viewed from the relative origin,
It can be seen from FIG. 1 that it is in the first quadrant, and the quadrant number is 1. Further, it can be seen from FIG. 2 that the zone number is 5. Since the quadrant number of the second sampling coordinate is 1 and the zone number is 5, the quadrant number difference is 0 and the zone number difference is 0. Therefore, from FIG. 3, the zone code of the fourth sampling coordinate is (01). Becomes For the in-zone address of the fourth sampling coordinate, zone number 5
Then, the in-zone address becomes (2,3), so (10
11). Therefore, the code data of the fourth sampling coordinate is (011011) obtained by adding these.

The encoding is performed as described above. In addition,
Unlike the above, if the drawing area of the fourth sampling coordinate overlaps the drawing area of the second sampling coordinate, the fourth sampling coordinate is not encoded. When the zone number does not correspond to that in FIG. 3, the zone area external code data (6 bits fixed length) indicating that it is outside the zone area is allocated, and thereafter, the same as the first sampling coordinate encoding. Two
Assign the absolute coordinates of the sampling coordinates. If the difference between the I-th sampling coordinate and the I-1th sampling coordinate, which is the target for determining whether or not to encode, is within 1 for both the X component and the Y component, the encoding is not performed as recommended.

In step S107, the pen lift-up information indicating that the input of one stroke drawing information is completed is encoded. The input pen lift-up information is encoded as (110) having a fixed length of 3 bits, as shown in "PLI" of the zone code table of FIG.

By performing a series of these processes, one stroke drawing information is encoded. It should be noted that encoding of a plurality of stroke information can be performed by repeating the processing of S101 to S107.

In the above description, whether or not the I-th sampling coordinate is to be coded is determined by the drawing area of the I-th sampling coordinate and the drawing area of the sampling coordinate which is closest to the I-th sampling coordinate and already coded. Although it is encoded by determining whether or not they overlap, the present invention is not limited to this, and when the previous sampling coordinate is not encoded, for example, the drawing area of the latest encoded sampling coordinate is used. Encoding may be performed even if they overlap. That is, if the (I-1) th sampling coordinate is not encoded, it may be determined by various methods such as encoding the next I-th sampling coordinate without fail.

Further, in the above description, when the drawing areas of the sampling coordinates overlap, the sampling coordinates to be excluded from the encoding target are the later sampling coordinates in the encoding time series. For example, in the example of FIG. When the drawing areas of the second sampling coordinates and the third sampling coordinates overlap, the third sampling coordinates are excluded from the encoding target. However, the present invention is not limited to this, and the third sampling coordinates are not the encoding target according to the positional relationship between the preceding and following sampling coordinates. You may make it select the sampling coordinate which becomes. That is, when the drawing areas overlap, any sampling coordinate may be omitted from encoding.

For example, when the fourth sampling coordinate of FIG. 5 is (22, 12) and the drawing is curvilinear at the point of the third sampling coordinate, the first sampling located before and after the second sampling coordinate. Since the positional relationship between the second sampling coordinates and the fourth sampling coordinates located before and after the third sampling coordinates has a larger shift than the positional relationship between the third sampling coordinates, the second sampling coordinates are excluded from the encoding target. It is possible to reduce the missing error of the sampling coordinates that occurs during decoding. That is, the encoding is performed so that the characteristics of the drawing input by handwriting at the time of decoding can be expressed.

More specifically, in a plurality of sampling coordinates where drawing areas overlap, for each sampling coordinate, a vector connecting the sampling coordinate and the sampling coordinate immediately before the sampling coordinate, the sampling coordinate, and the sampling coordinate The angle formed by the vector connecting the next sampling coordinate is calculated, and the encoding of the sampling coordinate having the smaller angle is omitted. That is, when the fourth sampling coordinate is (22, 12), the second
Regarding the sampling coordinates, an angle a formed by the vector between the first sampling coordinates and the second sampling coordinates and the vector between the second sampling coordinates and the third sampling coordinates, and the third sampling coordinates between the second sampling coordinates and the third sampling coordinates. When the angle b formed by the vector and the vector between the third sampling coordinate and the fourth sampling coordinate is calculated, the angle b becomes larger,
The encoding of the second sampling coordinates is omitted.
In this way, the drawing characteristics can be retained. Also,
In the case of sampling coordinates where drawing areas overlap, encoding of arbitrary sampling coordinates may be omitted.

The Nth sampling coordinate (final sampling coordinate) may be coded even if it overlaps with the drawing area of the latest coded sampling coordinate. In other words, regarding the final sampling coordinates, the final sampling coordinates must be encoded in order to avoid inconvenience in the displayed image due to the lack of the final sampling coordinates and the display of handwritten characters. May be.

In the above description, whether or not to encode is determined by whether or not the drawing area of the target sampling coordinate and the drawing area of the latest encoded sampling coordinate overlap each other. However, the present invention is not limited to this, and the determination may be made based on the size of the distance from the latest coded sampling coordinate. For example, a certain threshold is set, and if the distance is equal to or less than the threshold, encoding is not performed, and if the distance is equal to or greater than the threshold, encoding is performed. This threshold value is set according to the line width. For example, the threshold value may be half the line width value.

Further, the determination may be made not by the distance between the sampling coordinates but by the distance between the drawing areas of the sampling coordinates. That is, when the distance between the drawing area of a certain sampling coordinate and the drawing area of the sampling coordinate most recently coded at the sampling origin serving as the relative origin is within a certain distance, the coding of the above sampling coordinate is performed. Is omitted.

The coded data string of the coded data is shown in FIG.
And the code data for the attribute is followed by the code (X1) of the X coordinate of the first sampling coordinate and the code (Y1) of the Y coordinate of the first sampling coordinate.
The zone code (ZC (2)) of the second sampling coordinate and the zone address code (A of the second sampling coordinate)
(2)) continues. Here, the zone code of the second sampling coordinate is obtained by encoding the difference between the second sampling coordinate and the first sampling coordinate, and in the above example, (1
00010) corresponds to this. The sign of the in-zone address of the second sampling coordinate is (10
11). After that, a code (EZC (3)) that encodes the difference between the third sampling coordinate and the predicted coordinate of the third sampling coordinate and a code (A (3)) of the in-zone address of the third sampling coordinate follow. In the case of FIG. 5 described above, the code data for this third sampling coordinate is omitted. After that, as in the case of the third sampling coordinate, the data of the fourth sampling coordinate and thereafter continues, and finally the code of the pen list up information (P
LI) is located. Since the data from X1 to PLI is data for one stroke, the same data is repeated in the case of a plurality of strokes. The attribute code data obtained by encoding the attribute information is not always required at the beginning of one stroke and may be omitted.

Next, the decoding process (decompression process) will be described with reference to FIG. In S201, the code data is read, and "whether the 16th bit from the beginning of the unanalyzed code data matches the attribute code data (16-bit fixed length)" is analyzed, and if they match, S202 Move to. If they do not match, "whether the first to third bits of the unanalyzed code data match the code data (3-bit fixed length) of the pen lift-up information" is analyzed, and if they match, the process proceeds to S206. To do. If this also does not match, it is interpreted as the code data of the sampling coordinates, and the process proceeds to S203. Here, the process of S201 is performed in the main control unit 50. The following processing will be performed in the encoding unit 30.

At S202, the attribute code data is decoded into attribute information. As a result, 16 bits become the analyzed code data, and the head of the unanalyzed code data moves.
In S203, the counter is used to detect whether it is the first sampling coordinate or the I-th sampling coordinate. If it is the first sampling coordinate, the process proceeds to S204, and if it is the I-sampling coordinate, the process proceeds to S205.

At S204, the first sampling coordinates are decoded. In the above case, the resolution is 256 pixels x
Since there are 256 pixels, the code bit length is 8 bits for both the X coordinate and the Y coordinate. Therefore, 16 bits from the head of the unanalyzed data are the absolute coordinates of the first sampling coordinates.
As a result, 16 bits become parsed code data, and the head of unparsed code data moves.

In step S205, the I-th sampling coordinate is decoded. From the beginning of the unanalyzed code data, it is analyzed which one of the zone code data in FIG. 3 matches. If it is the second sampling coordinate in the case of FIG. 5, the head of the unresolved code data (code data of the second sampling coordinate)
From the code data following it,
The code data of the sampling coordinates is (100010101
Since it is 1), it can be seen that the first 6 bits match the zone code number 15 in FIG. Therefore, the first 6 bits are analyzed as the zone code. Further, the code number 15 analyzes the zone number 5 in the first quadrant as viewed from the first sampling coordinate. Since the zone number 5 can be represented by 2 bits for both the X coordinate and the Y coordinate, 4 bits following the zone code data are analyzed. Then, it is analyzed that the in-zone address is (2,3). Therefore, the second sampling coordinate is located in the first quadrant from the first sampling coordinate, is located in the fifth zone, and is the coordinate of (2,3) in the fifth zone, that is, (16,13). It is analyzed when it is located at. As a result, the zone code bit length of 6 bits and the zone address length of 4 bits become the analyzed code data, and the head of the unanalyzed code data moves.

Regarding the fourth sampling coordinate in the case of FIG. 5, since the code data is (011011), it can be understood that the first 2 bits match the zone code number 1 in FIG. Therefore, the first two bits are analyzed as the zone code. Also, with the code number 1, the zone number 5 in the first quadrant as seen from the second sampling coordinate.
Is parsed. And zone number 5 is the X coordinate,
Since the Y coordinate can be represented by 2 bits, 4 bits following the zone code data are analyzed. Then, it is analyzed that the in-zone address is (2,3). Therefore, the fourth sampling coordinate is from the second sampling coordinate to the first sampling coordinate.
It is located in the quadrant and located in the fifth zone, and the coordinates of (2,3) in the fifth zone, that is, (22,16)
It is analyzed when it is located at.

In this decoding process, since the third sampling coordinates are not coded, the third sampling coordinates are not decoded and the display contents are obtained by connecting the second sampling coordinates and the fourth sampling coordinates. Therefore, compared to the actual input, the third sampling coordinate is missing, but when the line width is thick and the drawing regions overlap, the sampling coordinates will be obstructed even if data is lost during decoding. Does not occur. In S206, the pen lift-up code data is decoded into pen lift-up information.

By performing a series of these processes, one stroke drawing information is decoded. When encoding a plurality of stroke information, it is possible to repeat the processing from S201 to S206.

As described above, in the stroke information encoding system of the first embodiment, the sampling coordinate A as the object of determination as to whether or not to encode and the closest previously encoded sampling coordinate B are used. If the drawing areas even partially overlap, the sampling coordinates A are not coded, so that it is possible to shorten the code data by not creating the code data of the sampling coordinates that does not make sense due to the overlap.

Next, the encoding process and the decoding process in the second embodiment will be described. First, the encoding process will be described. In the second embodiment, substantially the same processing as the processing shown in the schematic flow chart of FIG. 6 in the first embodiment is performed, but unlike the first embodiment, it is determined whether or not the pen areas in S105 overlap. S1 without performing the processing
By changing the encoding of the in-zone address of 06, the first
A “method of dividing a zone and designating a zone number” (hereinafter, referred to as a zone dividing method) different from the embodiment is applied. That is, in the first embodiment, the zone division method shown in FIG. 2 is applied, but the zone division method shown in FIG. 9 is applied. In the zone division method shown in FIG. 9, the zone number division is twice as large as that in the case of FIG. 2, and the number of pixels in the X direction and the Y direction in each zone number is doubled.

A concrete method of the encoding process is shown in FIG.
An explanation will be given using the stroke drawing information, which has a feature that the sampling coordinate interval such as 0 is large. For example,
In FIG. 10, the first sampling coordinate is (6, 6),
It is assumed that the second sampling coordinate is (22,22) and the third sampling coordinate is (40,40). Here, if the zone division method shown in FIG. 2 is applied, it will be as follows.

That is, the third sampling coordinate is located at the position (18, 18) when viewed from the second sampling coordinate and is in the first quadrant, but the third sampling coordinate depends on the zone division method in FIG. And the area outside the zone. Therefore, the zone code of the third sampling coordinate is the same as the third zone area code data (000010)
The absolute values of the sampling coordinates were added (00001
00010100000101000).

However, as in the present embodiment,
When the zone division method shown in FIG. 9 is applied, the third sampling coordinate is in the first quadrant as viewed from the second sampling coordinate by using FIG. 9 in which the third sampling coordinate is twice as large as the zone number division in FIG. It will be located at number 9. As a result, the difference between the quadrant number of the second sampling coordinate and the quadrant number of the third sampling coordinate becomes zero. Further, the zone number of the second sampling coordinate is 9 when the relative origin is the first sampling coordinate, so the difference between the zone number 9 of the second sampling coordinate and the zone number 9 of the third sampling coordinate is It becomes 0. Therefore, the zone code of the third sampling coordinate in FIG. 10 is (01). Also, the in-zone address is (2,2)
Since this zone number 9 can be represented by 4 bits, the in-zone address of the third sampling coordinate is (00100
010). Therefore, when these are added together,
(0100100010).

As described above, in the second embodiment, the number of pixels in the zone is increased and the zone number delimiter is increased to reduce the possibility of the area outside the zone.
The code length of data can be shortened.

Next, the decoding process will be described. In this decryption process, the decryption process is performed as shown in the schematic flow of FIG. 8 in the same manner as in the case of the first embodiment. That is, when the coded data is the sampling coordinates, it is determined whether the coded data is the coordinates after the first sampling coordinates or the second sampling coordinates. When the code data is the first sampling coordinates, the absolute coordinates are decoded, If the coordinates are after the sampling coordinates, the zone code and the in-zone address are analyzed and a decoding process is performed.

In the second embodiment, the number of pixels of the X component and the Y component in the zone is doubled as compared with the first embodiment, but the number of pixels is not limited to this, and is n times. (N is an integer of 3 or more). In addition, a plurality of zone division methods with different magnifications are provided, and the zone division method is selected from a plurality of zone division methods according to the distance between the sampling coordinate to be encoded and the sampling coordinate to be the relative origin. You may do it. In this case, the larger the distance between the sampling coordinates to be coded and the sampling coordinates to be the relative origin, the larger the scale factor for applying the zone division method. For example, in a certain handwriting input, encoding is performed from a start point to an end point of a stroke using a zone division method with a certain scale factor, and from the start point to an end point of another stroke is performed using a zone division method with another scale factor. To do. In this case, what kind of zone division method is used for coding may be noted in the header.

As described above, according to the stroke information coding method of the present embodiment, the code data can be shortened even if the sampling coordinates are normally outside the zone area. That is, even if the sampling coordinates of the drawing information to be input become large due to the reason that the sampling speed is slow or the stroke speed is fast, and the method of zone division shown in FIG. Coded data can be easily shortened by coding using a zone area having a large size. In addition, by defining a zone division method with different magnifications and different zone area sizes, and applying the zone division method according to the distance between the sampling coordinate that is the encoding target and the sampling coordinate that is the relative origin. , It is possible to perform appropriate encoding according to the distance.

Further, in the second embodiment described above, when the interval between sampling coordinates of input drawing information is large, encoding is performed using an enlarged zone area and the encoded data is shortened. Not only that, but the code data can be shortened even when the line width is thick. That is, when the line width becomes thick, the difference between the sampling coordinates tends to become large, but according to the zone division method as shown in FIG. 9, the code data can be shortened because it is contained in the zone area.

Here, the magnification of the zone number division, that is, the magnification of the number of pixels of each component of the X component and the Y component in the zone is determined according to the line width. For example, the zone division method shown in FIG. 9 is applied when the line width is 2 × 2 pixels, while when the stroke information having a line width of 5 × 5 pixels is encoded, as shown in FIG. It is advisable to use the zone delimiter in FIG. That is, the larger the line width, the larger the magnification.

As described above, since the coding is performed by applying the zone division method of the zone area according to the line width, each sampling coordinate is less likely to be outside the zone area and the code data can be shortened. In the above example, the degree of magnification is the same as the line width, but it is not limited to this.

Further, when the stroke information having various thicknesses is coded, zone delimiters corresponding to the respective thicknesses are selectively selected and coded using the zones. I don't care. For example, in a certain handwriting input, encoding is performed from a start point to an end point of a stroke using a zone division method with a certain scale factor, and from the start point to an end point of another stroke is performed using a zone division method with another scale factor. To do. In this case, what kind of zone division method is used for coding may be noted in the header.

In the above description, the case where the number of pixels of the X component and the number of pixels in the Y direction in each zone are the same has been described, but when the distance of the sampling coordinates is large in the horizontal direction, By using the zone dividing method shown in FIG. 12 in which the zone area is long in the horizontal direction and is less likely to be outside the zone area in the horizontal direction, the code data can be efficiently shortened. When the sampling coordinate has a large distance in the vertical direction, the zone division method shown in FIG. 13 is used in which the zone area is long in the vertical direction and is less likely to be outside the zone area in the vertical direction. It is possible to more efficiently shorten the coded data by performing the encoding by using the coded data.

Therefore, for example, a plurality of zone division methods in which the number of pixels in each zone in the X direction is different and the size of the zone area in the X direction is different are provided, and the sampling coordinates to be encoded and the relative origin are set. By applying the zone division method according to the distance in the X direction from the sampling coordinates, it is possible to perform appropriate encoding according to the distance. The zone divisions or zone widths in the zone division methods of FIGS. 12 and 13 are not limited to those described above, and any feature may be used as long as the zone area is larger. .

Next, the encoding process and the decoding process in the third embodiment will be described. First, the encoding process will be described. In the third embodiment, substantially the same processing as the processing shown in the schematic flow chart of FIG. 6 in the first embodiment is performed, but unlike the first embodiment, it is determined whether or not the pen areas in S105 overlap. S1 without performing the processing
By changing the encoding of the in-zone address of 06, the first
A zone division method different from those of the embodiment and the second embodiment is applied. That is, in the first embodiment, the zone division method shown in FIG. 2 is applied, and in the second embodiment, the zone division method shown in FIG. 9 is applied.
The zone division method shown in No. 4 is applied.

The zone division method shown in FIG. 14 uses a plurality of pixels as a unit of one in-zone address.
The plurality of pixels are 3 × 3 pixels in FIG.
That is, specifically, one in-zone address is assigned to a block of 3 × 3 pixels. This zone division method is applied when the line width is 3 × 3 pixels.

A specific method of encoding processing will be described. For example, in FIG. 15, when the first sampling coordinate is (3, 3) and the second sampling coordinate is (10, 4), in the zone division method shown in FIG. 2, the second sampling coordinate is the first When the sampling coordinate is the relative origin, it is (7, 1), and the second sampling coordinate is in the first quadrant as viewed from the relative origin and the zone number is 5. Therefore, the quadrant number difference is 0 and the zone number difference is It becomes 4. Therefore, the zone code is (100010) from FIG. Further, since the in-zone address is (3,1), the in-zone address code is (1101). Therefore, the code data of the second sampling coordinate is (10001
01101).

However, in the zone division method of this embodiment, the relative origin is set at the coordinate in the middle of the (1,1) address of the zone of zone number 1. That is, FIG.
The relative origin is set at the pixel at the center of the block of 3 × 3 pixels in the zone of zone number 1 of 4. In FIG. 14,
It is the part painted in black. Then, when the point (7, 1) is taken from this relative origin, the coordinates are the zone number 2
It becomes the coordinates of (2, 2) of the block of 3 × 3 pixels at the address of (0, 0) in the zone.

Therefore, the second sampling coordinate is in the first quadrant as viewed from the first sampling coordinate, and the zone number is 2, so that the quadrant number difference is 0 and the zone number difference is 1. Therefore, the code data of the second sampling coordinate is (1011) and the in-zone address is (0,
0). Therefore, the code data in the case of this embodiment is (101100).

Next, the decoding process will be described. In this decryption process, the decryption process is performed as shown in the schematic flow of FIG. 8 in the same manner as in the case of the first embodiment. That is, when the coded data is the sampling coordinates, it is determined whether the coded data is the coordinates after the first sampling coordinates or the second sampling coordinates. When the code data is the first sampling coordinates, the absolute coordinates are decoded, If the coordinates are after the sampling coordinates, the zone code and the in-zone address are analyzed and a decoding process is performed.

Here, in the decoding of the second sampling coordinates, by analyzing the zone code and the in-zone address, the second sampling coordinates have the zone number 2 in the first quadrant as viewed from the first sampling coordinates. It can be known that the address in the zone is (0, 0) within the area of No. 3, but since the more detailed sampling coordinates are not decoded, the address in the zone corresponds to the display unit 20 3 Send the data of the coordinates of the center of the block of 3 pixels. In other words, for the second sampling coordinates, the coordinates indicated by hatching when the in-zone address of zone number 2 is (0, 0) are displayed on the display unit 2.
Send to 0. As for these coordinates, since the coordinates indicated by the black square of the zone of zone number 1 are the relative origin, the data of the coordinates (9, 3) are sent. Therefore, the display unit 20
Will display the unit coordinates centered on the sent coordinates in black. That is, in FIG. 14, nine pixels corresponding to the address (0, 0) of the zone number 2 are displayed in black.

As described above, in the stroke information coding method of the present embodiment, since the unit of the in-zone address as shown in FIG. 14 is coded by using the unit corresponding to the line width, the code data can be shortened. That is, since one zone address is assigned to a block of 3 × 3 pixels,
Since each sampling coordinate does not easily fall outside the zone area and the zone number becomes small, the code data can be shortened.

In the above example, one in-zone address is assigned to a block of 3 × 3 pixels, but the unit of this in-zone address is the same as the line width. That is, when the stroke information of 5 × 5 pixels is encoded, the unit of the in-zone address is 5 ×
Assuming that there are 5 pixels, one in-zone address is assigned to a block of 5 × 5 pixels. On the other hand, the unit of the in-zone address does not have to be the same size as the line width.

Further, although each sampling coordinate is processed so as to be the center of the in-zone address at the time of encoding / decoding, the present invention is not limited to this. For example, the relative origin is set as the lower left coordinate at the address (0,0) of the zone of zone number 1, or the coordinate sent to the display unit 20 is set as the lower left coordinate at 3 × 3 pixels of the corresponding address. 3 × 3 pixels having the coordinates at the lower left position may be displayed in black.

Further, when the stroke information having various line widths is coded, the unit of the address in the zone is selectively selected according to the line width and the zone is used for the coding. I don't care. For example, the larger the line width,
A zone division method in which the number of pixels corresponding to one in-zone address is large is applied. In this case, what kind of zone is used for encoding may be recorded in the header.

In the description of the third embodiment, the number of pixels corresponding to one in-zone address is selected according to the line width. However, the sampling coordinates to be coded and the sampling coordinates as the relative origin are selected. The method of the third embodiment may be applied even when the distance between and is long. That is, even if the line width is 1 × 1 pixel and the distance is long, the method of the third embodiment is applied. In this case,
When data of a certain coordinate is sent to the display unit 20 during decoding, the display unit 20 displays only the coordinate. Therefore, although there is a possibility that the actual sampling coordinates and the displayed coordinates may deviate from each other, by doing so, the code data is shortened by applying the method of the third embodiment even when the line width is not thick. be able to.

Although the present invention has been described with reference to the first to third embodiments, the present invention is not limited to these embodiments, and the above embodiments may be combined and coded. You can also For example, by combining the first embodiment and the second embodiment, the number of pixels in the zone is increased to increase the zone number delimiter, and the sampling coordinate of the most recently coded sampling coordinate When the drawing area overlaps with the drawing area, encoding is not performed, or the first embodiment and the third embodiment are combined to use the unit of the in-zone address according to the line width. Regarding the sampling coordinates, if the drawing area of the sampling coordinates most recently coded and the drawing area overlap, the coding is not performed.

In the above embodiment, the sampling coordinates are represented by absolute coordinates, but they may be relative coordinates from a certain coordinate. Further, although the zone code data is created using the zone code table of FIG. 3, the invention is not limited to this.

A plurality of attribute code data may be provided at the head of one stroke drawing code data. That is, in FIG. 7, when the code data strings of a plurality of strokes are sequentially arranged and the data of X1 to PLI are repeatedly stored following the PLI data of the previous stroke, the attribute code data of each stroke is The attribute code data at the head should be stored together. Further, a parameter common to each 1-stroke drawing code data may be provided by providing a header at the head of the code data string and inserting the header therein.

In each of the above embodiments, the I-th sampling coordinate is coded by the difference between the most recent coded sampling coordinate or the I-1th sampling coordinate. The difference between the predicted coordinate and the predicted coordinate may be encoded. Further, although each sampling coordinate is set to the center of the drawing area, the present invention is not limited to this, and the sampling coordinates may be set to the lower left, the upper right, etc. of the drawing area.

[0089]

According to the stroke information coding method of the first aspect of the present invention, it is determined whether or not the sampling coordinates are coded, and if the coding is not necessary, the code is used. Since no encoding is performed, unnecessary encoding can be prevented,
The code data can be shortened. Further, in particular, according to the stroke information encoding method of the second aspect, the encoded data can be shortened and the encoding of sampling coordinates, which does not make sense due to overlapping drawing areas, is omitted. There is almost no obstacle in doing so.
Further, in particular, according to the stroke information encoding method of the third aspect, the encoded data can be shortened and the encoding of sampling coordinates within a certain distance is omitted, so that there is almost no obstacle in decoding.

Further, according to the stroke information encoding method of the fourth aspect, encoding of sampling coordinates is omitted in a plurality of sampling coordinates in which drawing areas partially overlap, so that the code data can be shortened. it can. Further, in particular, according to the stroke information encoding method described in claim 5, since encoding of sampling coordinates is omitted so as to express the characteristics of drawing, even in decoding,
Features drawn by handwriting can be represented. Further, in particular, according to the stroke information encoding method according to the sixth aspect, the encoding of the sampling coordinates having a small bending degree is omitted, so that the sampling coordinates having a large bending degree are encoded and drawn. You can leave the features.

Further, according to the stroke information encoding method of the seventh aspect, since the zone division method according to the characteristics of the input drawing information is applied, the code data can be shortened. Further, according to the stroke information encoding method of the eighth aspect, the possibility that the sampling coordinates enter the zone area increases, and the code data does not become long outside the zone area. Particularly, according to the stroke information encoding method of claims 9 and 10, since the zone division method in which the size of the zone area is different according to the distance between the sampling coordinates is applied, it is suitable according to the distance. By applying the zone division method, the coded data can be shortened without the sampling coordinates being outside the zone area. In particular, the sampling interval of the drawing information to be input becomes large due to the reason that the sampling speed is slow, the stroke speed is fast, etc., and conventionally, the code data can be shortened even when the drawing information is frequently outside the zone area.

Particularly, according to the stroke information encoding method of the eleventh and twelfth aspects, since the zone division method in which the size of the zone area is different according to the line width of the drawing information input is applied, By applying a zone division method suitable for the distance, the sampling coordinates are not outside the zone area and the code data can be shortened. In particular, according to the stroke information encoding method of claim 13, by applying a zone division method suitable for the distance in the X direction, the sampling coordinates are not outside the zone area and the encoded data is shortened. can do. Also,
According to the stroke information encoding method of claim 14, by applying a zone division method suitable for the distance in the Y direction, the sampling coordinates are not outside the zone area and the encoded data is shortened. You can Further, according to the stroke information encoding method according to any one of claims 15 to 17, while the sampling coordinate of the encoding target is within the zone area, the code data of the in-zone address does not become long, so that the code data as a whole is Can be shortened.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a quadrant delimiter in a stroke information encoding method of Recommendation JT-T150 and a stroke information encoding method of the present invention.

FIG. 2 is an explanatory diagram showing a stroke information encoding method of Recommendation JT-T150 and a zone division method in the stroke information encoding method of the present invention.

FIG. 3 is an explanatory diagram showing a zone code table in the stroke information encoding method of Recommendation JT-T150.

FIG. 4 is a block diagram showing a configuration of a handwriting input device of the present invention.

FIG. 5 is an explanatory diagram illustrating an encoding process according to the first embodiment.

FIG. 6 is a flowchart diagram for explaining an encoding process.

FIG. 7 is an explanatory diagram showing the configuration of a coded data string of drawing information generated after the encoding process.

FIG. 8 is a flow chart diagram for explaining a decoding process.

FIG. 9 is an explanatory diagram showing a zone division method according to the second embodiment.

FIG. 10 is an explanatory diagram illustrating an encoding process according to a second embodiment.

FIG. 11 is an explanatory diagram showing another zone division method based on the second embodiment.

FIG. 12 is an explanatory diagram showing another zone division method based on the second embodiment.

FIG. 13 is an explanatory diagram showing another zone dividing method according to the second embodiment.

FIG. 14 is an explanatory diagram showing another zone division method based on the third embodiment.

FIG. 15 is an explanatory diagram illustrating an encoding process according to a third embodiment.

[Explanation of symbols]

 A handwriting input device 10 input unit 20 display unit 30 encoding unit 40 storage unit 50 main control unit

Claims (17)

[Claims] 1. A stroke information encoding method for sampling handwritten drawing information and compressing the coordinate information thereof, wherein certain sampling coordinates are encoded according to a relationship with a sampling coordinate serving as a relative origin. A stroke information encoding method characterized by determining whether or not to perform. 2. When determining whether or not to code the sampling coordinates, the drawing area of the sampling coordinates described above and the drawing area of the sampling coordinates most recently coded at the sampling coordinates serving as the relative origin. 2. The stroke information encoding method according to claim 1, wherein the encoding of the certain sampling coordinate is omitted when even some of the points overlap. 3. When determining whether or not to code the sampling coordinates, the drawing area of the sampling coordinates described above and the drawing area of the sampling coordinates most recently coded at the sampling coordinates serving as the relative origin. The stroke information encoding method according to claim 1, wherein the encoding of a certain sampling coordinate is omitted when the distance is within a certain distance. 4. A stroke information encoding method for sampling handwritten drawing information and compressing the coordinate information thereof, wherein encoding of at least one sampling coordinate is omitted in a plurality of sampling coordinates where at least a part of a drawing area overlaps. A stroke information encoding method characterized by: 5. The sampling coordinate for which the encoding is omitted is selected so that the characteristic of the drawing input by handwriting can be expressed when the encoding of the sampling coordinate is omitted. Stroke information encoding method. 6. A plurality of sampling coordinates in which drawing areas overlap each other, for each sampling coordinate, a vector connecting the sampling coordinate and a sampling coordinate immediately preceding the sampling coordinate, and the sampling coordinate and a sampling coordinate next to the sampling coordinate. The stroke information encoding method according to claim 4 or 5, wherein an angle formed by a vector connecting to and is calculated, and encoding of a sampling coordinate having the largest angle is omitted. 7. A stroke information coding method for sampling handwritten drawing information and compressing its coordinate information, wherein coding is performed by applying a zone division method according to the characteristics of input drawing information. And stroke information encoding method. 8. A stroke information coding method for sampling handwritten drawing information and compressing coordinate information thereof, in at least one zone division method, in at least one of an X direction and a Y direction in a zone having the smallest number of pixels. A stroke information encoding method, wherein the number of pixels in one direction is 4 or more. 9. A plurality of zone division methods having different sizes of zone areas are provided, and the zone division method is provided according to a distance between a sampling coordinate of an encoding target and a sampling coordinate serving as a relative origin in input drawing information. 9. The stroke information coding method according to claim 7, wherein a zone division method is selected from a plurality of zone division methods and applied. 10. A zone division method that applies a larger zone area as the distance between a sampling coordinate to be coded and a sampling coordinate serving as a relative origin becomes larger in input drawing information. Item 9
Stroke information encoding method described in. 11. A plurality of zone division methods having different zone areas are provided, and a zone division method is selected from the plurality of zone division methods and applied according to the line width of input drawing information. The stroke information encoding system according to claim 7 or 8. 12. The stroke information encoding method according to claim 11, wherein a zone division method in which the zone area is larger is applied as the line width of the input drawing information is larger. 13. A plurality of zone division methods are provided in which the sizes of the zone areas in the X direction are different, and the X direction between the sampling coordinates to be encoded in the drawing information to be input and the sampling coordinates to be the relative origin is set. 8. The zone division method is selected and applied from the plurality of zone division methods according to the distance.
Alternatively, the stroke information encoding method according to item 8. 14. A plurality of zone division methods in which the size of the zone area in the Y direction is different are provided, and the Y direction between the sampling coordinates of the encoding target and the sampling coordinates of the relative origin in the drawing information to be input is provided. 8. The zone division method is selected and applied from the plurality of zone division methods according to the distance.
Alternatively, the stroke information encoding method according to item 8. 15. Sampling handwritten drawing information,
A stroke information encoding method for compressing the coordinate information, wherein a zone division method having a unit of an in-zone address in which a plurality of pixels are associated with one in-zone address is applied. 16. A plurality of zone division methods having different numbers of pixels corresponding to in-zone addresses are provided, and the zone division method is selected from the plurality of zone division methods according to the line width of drawing information to be input. The stroke information encoding method according to claim 15, wherein the stroke information encoding method is applied. 17. The stroke information encoding method according to claim 16, wherein in the input drawing information, a zone division method in which the larger the line width is, the larger the number of pixels corresponding to one in-zone address is applied, is applied. method.