JP3224120B2 - Data processing method for coordinate input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device for outputting, as two-dimensional coordinate data, coordinate data of a pressed position obtained by a pressing operation of an input pen, a fingertip or the like.

[0002]

2. Description of the Related Art Coordinate input devices are classified into a resistive film system, an electromagnetic induction system, an electrostatic coupling system, an electromagnetic transfer system, and the like according to the principle of operation. Here, one example is the resistive film system. A description is given below. FIG. 9 is an exploded perspective view of a conventional general resistive film tablet, and FIG. 10 is a sectional view of a main part thereof. The illustrated resistive tablet device includes a first resistive sheet 11 disposed on an upper part and a second resistive sheet 12 disposed on a lower part of the first resistive sheet 11. Each of the resistance sheets 11 and 12 is made of a base material 11a or 12a made of a flexible organic polymer or the like.
And conductive thin films 11b and 12b formed on opposing surfaces of the base materials 11a and 12a.
The surfaces of 1b and 12b form a conductive surface. On the other hand, on the upper surface of the second resistance sheet 12, the first resistance sheet 11
And a large number of spacers 13
Is arranged. A pair of first electrodes 14a and 14b are provided in parallel at both ends of the first resistance sheet 11, and both ends of the second resistance sheet 12 are orthogonal to the pair of first electrodes 14a and 14b. A pair of second
The electrodes 15a and 15b are provided in parallel. And
It is configured such that a voltage can be alternately applied between the first electrodes 14a and 14b and between the second electrodes 15a and 15b at a predetermined timing. In addition, the periphery of the first resistance sheet 11 and the periphery of the second resistance sheet 12 are adhered to each other by an adhesive layer 16.

[0003] Therefore, as shown in FIG.
When the first resistance sheet 11 is not pressed, the resistance sheets 11 and 12 are held in a non-contact state by the spacer 13. On the other hand, as shown in FIG. 10B, when a predetermined portion of the first resistance sheet 11 is pressed with, for example, the input pen 17 or the like, the conductive thin film 11 of each of the resistance sheets 11 and 12 is pressed.
Of the b and 12b, only the portion corresponding to the pressed portion contacts. Here, the first and second electrodes 14a and 14b and the second electrodes 15a and 15b to which voltages can be alternately applied are provided on the respective resistance sheets 11 and 12 in the X-Y axis directions orthogonal to each other. Voltage-applied resistance sheet,
For example, a potential gradient is generated on the first resistance sheet 11 side, and a potential difference is generated by contact with the other resistance sheet (in this case, the second resistance sheet 12). Therefore, coordinate data (X, Y) as an input position (pressing position) on the XY coordinate axis can be detected by applying a voltage alternately to X and Y from the ratio of the voltage drop component to the applied voltage. . That is, by pressing a predetermined portion of the first resistance sheet 11, the corresponding portions of the conductive thin films 11b and 12b are brought into local contact, whereby various data can be input. The first resistance sheet 11 is configured as an input surface during an input operation.

[0004]

However, in the above-described conventional apparatus, when performing position detection, mechanical contact such as pressing with an input pen 17 or the like accompanies the pen pressure (pen pressure).
The potential at the contact point becomes unstable due to the subtle change in
There is a problem that erroneous data is generated. Therefore, conventionally, as disclosed in Japanese Patent Application Laid-Open No. 58-94069, a deviation between coordinate data sequentially taken out with the movement of the pressing point is calculated, and the calculated deviation is set to a coordinate smaller than a predetermined value. A data processing method has been proposed in which only data is treated as coordinate data having continuity, and all other data is treated as abnormal data (erroneous data). However, in such a case, there are the following inconveniences. . (1) Despite individual differences in the resolution and the like of individual tablets, the deviation between coordinate data serving as a criterion is constant, so that individual adjustment is required for each tablet. (2) Even erroneous data caused by chattering immediately after writing is mistaken as valid data if the deviation between coordinate data is equal to or less than an allowable value. (3) When the moving speed (writing speed) of the input pen increases,
Because the deviation between coordinate data becomes larger by that amount,
Even valid data may be recognized as erroneous data, resulting in data loss. (4) Since it is not possible to cope with sudden noise or the like, the recognition rate such as character recognition is reduced, and only valid data cannot be stably output.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem. When a predetermined portion of an input surface is pressed, coordinate data corresponding to the pressed position is sequentially taken in, and the data is read. Of the captured coordinate data, in a coordinate input device that outputs only valid data, before performing a normal input operation, first capture coordinate data obtained by handwriting input under predetermined conditions at a certain timing, The moving distance between the second coordinate data and the third coordinate data, the linear axis between the first coordinate data and the second coordinate data, the second coordinate data, and the third coordinate data by sequentially using the three coordinate data. The amount of change in the angle between the coordinate data and the linear axis is calculated, and the moving distance and the degree of the angle change, which are individually obtained, are totaled. Performs initial setting processing for setting a moving distance corresponding to the angle change reference value is a threshold value of the valid data determination. Then, during a normal input operation, the following input data processing is performed. That is,
Using the first coordinate data obtained immediately after writing and the two pieces of coordinate data input immediately after writing, the movement distance between the first coordinate data and the second coordinate data, and the first coordinate data and the second coordinate data are used. The amount of angle change between the linear axis between the second coordinate data and the linear axis between the second coordinate data and the third coordinate data is calculated, and the calculation result and the valid data determination set by the initial setting process are performed. Then, when at least one of the calculation results is within the threshold value, the first coordinate data immediately after writing is output as valid data. In addition, the moving distance between the second coordinate data and the third coordinate data using the arbitrary coordinate data obtained during the writing and the two pieces of valid data input immediately before the writing, and the first coordinate data And the linear change between the second coordinate data and the linear coordinate between the second coordinate data and the third coordinate data are calculated, and the calculation result and the validity set by the initial setting process are calculated. A comparison is made with a data determination threshold value, and when at least one of the calculation results is within the threshold value, arbitrary coordinate data is output as valid data.

[0006]

In the data processing method of the coordinate input device according to the present invention, a threshold for valid data determination is set by an initial setting process to eliminate individual differences such as resolution of a coordinate input unit (tablet). In the input operation of, based on the threshold value for valid data determination set previously, it is determined whether or not the coordinate data obtained immediately after writing or during writing is valid data. Erroneous data generated due to chattering, writing pressure change, etc. immediately after is reliably eliminated, and the first valid data obtained immediately after writing can be accurately captured and output, and any valid data obtained during writing can be obtained. Data can also be output stably.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a block diagram showing a functional configuration of the coordinate input device according to the present invention. 2 is a doublet 1 serving as a coordinate input medium.
And a drive circuit 3 for driving the doublet 1 based on a control signal given by an arithmetic processing unit (CPU) 2 and a detection circuit 4 for detecting coordinate data from a potential signal output from the doublet 1. , Arithmetic processing unit (C
The PU 2 performs various data processing (described later) on the coordinate data detected by the detection circuit 4, and outputs the processing result to a computer 5 or the like as a host device. In the present embodiment, the data processing is performed by the arithmetic processing unit (CPU) 2, but various data processing described later may be performed by the computer 5 that actually receives the data.

Next, a data processing form in this embodiment will be described. FIG. 1 is a flowchart of an initial setting process in the data processing method of the coordinate input device according to the present invention. This initial setting process is performed to eliminate individual differences such as resolution between the individual tablets 1, and is faster than a normal input operation on the input surface of the doublet 1 during handwriting input. The pen point or the like is pressed at the writing speed, and a figure such as a circle is drawn while keeping the pen point or the like away from the input surface. By the way, in the handwriting input at the time of the initial setting, the pen point or the like is surely pressed against the input surface so that the "erroneous data" is not included as much as possible in the coordinate data obtained via the tablet 1. In addition, as for the graphic input at the time of the initial setting, a graphic in which both a moving distance and an amount of change in angle, which will be described later, both increase is appropriately selected. Further, as an example, pen information (flag) indicating whether an input pen or the like is pressed on the input surface of the doublet 1 is added to the individual coordinate data obtained by the input operation. The data is output from the arithmetic processing unit (CPU) 2 to a higher-level device (computer 5) or the like.

In the flowchart of the initial setting process shown in FIG. 1, first, in step S1, the count value of the data count is reset to zero (count = 0). next,
In step S2, information indicating the pressed state of the pen tip or the like (f
The data indicating that the pen tip or the like is being pressed on the input surface of the tablet 1, for example, pen DOWN (flag)
When the three coordinate data to which the information of (= 1) is continuously added are collected, the process proceeds to step S3.

In step S3, using the above three coordinate data, first, as shown in FIG.
The movement distance ΔL between the second and third coordinate data P3 is obtained.
Further, the first coordinate data P1 and the second coordinate data P2
The angle change amount Δθ formed by the linear axis K1 between the second coordinate data P2 and the linear axis K2 between the third coordinate data P3 is determined. Next, in step S4, the count value of the data count is incremented by one (+1), and further in step S5
Then, it is determined whether or not the count value of the data count updated in step S4 has reached a preset data accumulation number n.

Here, the "data accumulation number" refers to the number of times of sampling of accumulated data required to obtain a threshold value for valid data determination, which will be described later. Is set as appropriate. In addition,
In this type of coordinate input device, it is possible to collect about 100 data per second as the number of data samplings per time.
Even if it is set to 500 to 1000, the data collection time is completed within 10 seconds.

Subsequently, in step S5, if the count value of the data count is less than the data accumulation number n, the process returns to step S3 again, and the pen DOWN (flag = 1)
The moving distance ΔL and the angle change amount Δθ are respectively obtained using the fourth coordinate data to which the above information is continuously added. That is, in the second step S3, the fourth coordinate data is newly set as the third coordinate data P3, and the two coordinate data input immediately before that, that is, the second and third coordinate data are obtained. As described above, the moving distance ΔL and the angle change Δ
Find θ. Thereafter, every time the movement distance ΔL and the angle change amount Δθ are obtained in step S3, the count value of the data count is incremented by 1 in step S4, and the count value of the updated data count reaches the data accumulation number n. Until the step S3, the frequencies of the moving distance ΔL and the angle variation Δθ individually obtained in step S3 are accumulated.

In step S3, the moving distance ΔL and the angle change Δθ are obtained only when three consecutive pieces of coordinate data to which information during writing (flag = 1) is added are continuously detected. Information indicating that the pen tip or the like is not pressed on the input surface of the tablet 1, for example, the pen U
If the coordinate data to which the information of P (flag = 0) is added is detected and the information of the pen DOWN (flag = 1) is not consecutive three times, the moving distance ΔL and the angle change Δθ are not obtained. .

FIG. 4 is a diagram showing a distribution state of the cumulative frequency of the moving distance ΔL and the angle change Δθ obtained when the count value of the data count reaches the data cumulative number n. In FIG. 4, the movement distance ΔL is taken on one of two horizontal axes orthogonal to each other, the angle change amount Δθ is taken on the other, and the respective degrees T are taken on the vertical axis. Here, in the handwriting input at the time of the initial setting, as described above, the pen point or the like is securely pressed against the input surface so that the coordinate data obtained via the tablet 1 does not include "erroneous data" as much as possible. Since a figure in which both the moving distance ΔL and the angle variation Δθ obtained in S3 are large is selected, for example, if the input coordinate data contains less than 1% erroneous data. Assuming that in the case of the three-axis coordinate system (ΔL axis, Δθ axis, T axis) shown in FIG. 4, the origin (0) position is set as the maximum frequency Tmax on the axes of the movement distance ΔL and the angle change Δθ. , Frequency curves R1, R2, R3 are obtained.

In step S6, the predetermined angle change reference value S and the corresponding moving distance P are determined by referring to the cumulative frequency obtained by the processing in steps S1 to S4. Set as threshold value. This will be described schematically using the distribution state of the cumulative frequency shown in FIG. 4. First, the axis of the angle change reference value S is set at a position where the angle change is relatively small with respect to the axis of the angle change amount Δθ. Set. At this time, the angle change reference value S
Is properly defined, since the axis of the angle change reference value S intersects the frequency curve R3 on the horizontal axis, the virtual axis (P) passing through the intersection and orthogonal to the axis of the angle change reference value S And the virtual axis P on the axis of the moving distance ΔL
Find the numerical value of. Then, a predetermined angle reference value S
And the moving distance P obtained in correspondence therewith are set as threshold values for valid data determination during a normal input operation.

As a result, of the coordinate data obtained by handwriting input at the time of initial setting, valid data of 99% or more (assuming that erroneous data is less than 1%) is an angle data in the coordinate system shown in FIG. It enters any one of the first to third valid data areas (E1 to E3) surrounded by the axis of the change reference value S and the axis of the moving distance P corresponding thereto, and only the remaining erroneous data of less than 1% Will enter the other invalid data area E4.

Incidentally, the "angle change reference value" is a value appropriately determined by various parameters such as the number of samplings per time, the resolution of the tablet 1, and the writing speed of an input pen or the like. is not.
Also, the threshold values S, P for valid data determination obtained here
Does not need to perform the above-described initial setting processing when the tablet performance and resolution are known in advance and S and P can be set as reference values without performing handwriting input.

FIG. 5 is a flowchart of input data processing in the data processing method of the coordinate input device according to the present invention, and shows a processing procedure immediately after writing at the time of a normal input operation. First, in step S11, the attached number (i) of the coordinate data extracted from the doublet 1 is reset (i = 1). Next, in step S12, immediately after writing (the pen state is fl
Immediately after switching from ag = 0 to flag = 1), the first coordinate data i taken out of the doublet 1 is set to “1”, and the pen DOWN together with the coordinate data i.
Two pieces of coordinate data i + 1 and i + 2 extracted with information of (flag = 1) added are collected.

Next, in step S13, as described above, the three coordinate data i, i + 1, i obtained immediately after writing.
Using +2, as shown in FIG. 7, the first coordinate data i
And the moving distance ΔLi between the second coordinate data i + 1 and the second coordinate data i + 1 are calculated. Further, the first coordinate data i and the second coordinate data i
+1 between the linear axis K1 between +1 and the second coordinate data i + 1 and the linear axis K2 between the third coordinate data i + 2.
Calculate θ. Subsequently, in step S14, the calculation result (Δθ, ΔLi) in step S13 is compared with the threshold (S, P) for valid data determination set in the initial setting process.

If the first coordinate data i obtained immediately after writing is erroneous data, the angle change Δθ calculated by the three coordinate data i, i + 1, i + 2 immediately after writing and The moving distance ΔLi is larger than the thresholds S and P for valid data determination. Therefore, in that case, the process proceeds to step S15, and the first coordinate data i is erroneously added with information indicating that the first coordinate data i is erroneous data, for example, pen information (flag = 2). Transfer as data. In the data processing immediately after writing, it is not necessary to grasp the continuity of the coordinate data. Therefore, information of the pen UP (flag = 0) is added as information indicating that the coordinate data i is erroneous data. You may.

Further, in step S16, the attached number (i) of the coordinate data is incremented by 1 to "i = 2", and the process returns to step S12 to collect coordinate data i + 1 and i + 2. At this point, since the first piece of coordinate data i immediately after writing has already been processed as erroneous data, the data treated as coordinate data i + 1 and i + 2 in the previous arithmetic processing is updated as coordinate data i and i + 1, respectively. You. Then, a new fourth coordinate data i +
2 are collected, and the moving distance ΔLi and the angle change Δθ are calculated in step S13 in the same manner as described above.

Thereafter, by updating the coordinate data i immediately after the writing, at least one of the angle change amount Δθ and the moving distance ΔLi calculated based on the coordinate data i, i + 1, i + 2 in the comparison result of step S14 becomes:
If it is determined that the values are within the thresholds S and P for valid data determination, the data treated as the first coordinate data i at that time is valid data, and therefore, step S1
Go to 7. In step S17, information indicating the effect, for example, information on the pressed state (flag = 1) of the pen tip or the like is added to the coordinate data i determined to be valid data, and this is transferred as valid data. At this time, the coordinate data i
Is determined as valid data, the coordinate data i + 1 and i + 2 forming a pair with the data are also valid data. Therefore, in step S17, the second coordinate data i + 1 and i + 2 are valid together with the first coordinate data i. You may make it transfer as data. When the first valid data (flag = 1) immediately after the writing is transferred in this way, the processing exits the input data processing immediately after the writing.

Immediately after writing, pen DOWN (flat
All the coordinate data for which the information of g = 1) is not obtained three or more times consecutively are transferred to a computer or the like as erroneous data (flag = 0 or flag = 2 is added). As information indicating whether or not the coordinate data extracted from the tablet 1 immediately after writing is valid data, information other than the pen pressing state (flag) may be added. In order to simplify simplification, the pressed state of the pen (f
lag) is preferred.

FIG. 6 is a flowchart of input data processing in the data processing method of the coordinate input device according to the present invention, which shows a processing procedure during writing during a normal input operation. First, in step S21, arbitrary coordinate data N extracted from the tablet 1 during writing (while the pen state is continuous with flag = 1) is collected. Next, in step S22, as shown in FIG. 8, the arbitrary coordinate data N obtained in the middle of writing and the two valid coordinate data N-1 and N-2 input immediately before are used as shown in FIG. , The second coordinate data N−1 and the third coordinate data N
Then, a moving distance ΔL is calculated. Further, the angle change formed by the linear axis K1 between the first coordinate data N-2 and the second coordinate data N-1 and the linear axis K2 between the second coordinate data N-2 and the third coordinate data N Calculate the quantity Δθ.

Subsequently, in step S23, the calculation results (Δθ, ΔL) in step S22 are compared with the thresholds (S, P) for valid data determination set in the initial setting process. . Here, if the arbitrary coordinate data N obtained during writing is erroneous data, the angle change amount Δθ calculated using the three coordinate data N-1, N-2, and N and the movement The distance ΔL is larger than the thresholds S and P for valid data determination. Therefore, in that case, the process proceeds to step S24, and the coordinate data N is transferred as erroneous data in a form in which information indicating that the coordinate data N in the middle of writing is erroneous data, for example, pen information (flag = 2) is added.

On the other hand, in step S23, the angle change Δθ calculated based on the coordinate data N-1, N-2, N
And at least one of the moving distance ΔL,
When it is determined that the values are within the thresholds S and P for valid data determination, the process proceeds to step S25 because the coordinate data N obtained during writing is valid data. Step S25
Then, information indicating that fact, for example, information on the pressed state (flag = 1) of the pen tip or the like is added to the arbitrary coordinate data N determined to be valid data and transferred as valid data. . Thereafter, coordinate data is sequentially collected, and it is determined whether each data is valid data or erroneous data, and information (flag) indicating that is added, and data transfer is performed.

[0027]

As described above, according to the present invention,
By setting a threshold value for valid data determination for each coordinate input device by the initial setting process, it is possible to eliminate individual differences such as the resolution of the coordinate input unit (tablet). Further, at the time of a normal input operation, the validity of coordinate data obtained immediately after writing or during writing is determined based on both the moving distance and the amount of angle change based on the previously set threshold for valid data determination. This makes it possible to process coordinate data sequentially taken out at a certain timing in real time, and it is possible to reliably eliminate erroneous data due to sudden noise, chattering immediately after writing, or a change in writing pressure. In addition, by performing handwriting input at the time of initial setting at a speed higher than the writing speed at the time of normal input operation, the deviation between coordinate data becomes large as in the above conventional example, so that valid data is regarded as erroneous data. Since mis-recognition does not occur, data loss due to mis-recognition can be prevented. As a result, since it is possible to accurately capture the first valid data obtained immediately after writing or any valid data obtained during writing, only the valid data from the coordinate data obtained by the input operation can be stably obtained. It is possible to output, thereby improving the recognition rate such as character recognition.

[Brief description of the drawings]

FIG. 1 is a flowchart of an initial setting process according to the present invention.

FIG. 2 is a functional block diagram of the coordinate input device.

FIG. 3 is a diagram showing parameters at the time of initial setting.

FIG. 4 is a diagram illustrating a distribution state of accumulated frequencies in an initial setting process.

FIG. 5 is a flowchart of input data processing immediately after writing.

FIG. 6 is a flowchart of input data processing during writing.

FIG. 7 is a diagram showing parameters immediately after writing.

FIG. 8 is a diagram showing parameters during writing.

FIG. 9 is an exploded perspective view of the resistive film tablet.

FIG. 10 is a sectional view of a main part of the resistive film tablet.

[Explanation of symbols]

 Reference Signs List 1 tablet 2 arithmetic processing unit (CPU) 3 drive circuit 4 detection circuit 5 computer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-298490 (JP, A) JP-A-2-267614 (JP, A) JP-A-2-186418 (JP, A) JP-A-60-1985 114924 (JP, A) JP-A-58-94069 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06F 3/03-3/033 G06K 9/62

Claims (2)

(57) [Claims] 1. A coordinate input device for sequentially inputting coordinate data corresponding to a pressed position when a predetermined position on an input surface is pressed, and outputting only valid data among the input coordinate data. The moving distance between the second coordinate data and the third coordinate data, and the first coordinate data are sequentially taken using three pieces of coordinate data while taking in the coordinate data obtained by the handwriting input below at a fixed timing. And the linear axis between the second coordinate data and the linear axis between the second coordinate data and the third coordinate data are obtained, and the moving distance and the frequency of the angular change obtained individually are accumulated. Then, while referring to the cumulative frequency obtained thereby, a predetermined angle change reference value and a corresponding moving distance are set as threshold values for valid data determination. In the normal input operation, the first coordinate data obtained immediately after writing and the two coordinate data input immediately thereafter are used to move between the first coordinate data and the second coordinate data. The distance and the amount of angle change between the linear axis between the first coordinate data and the second coordinate data and the linear axis between the second coordinate data and the third coordinate data are calculated. Comparing at least one of the calculation results with the threshold for valid data determination set by the initial setting process, and converting the first coordinate data immediately after writing to valid data when at least one of the calculation results is within the threshold. A data processing method for a coordinate input device, characterized by performing input data processing of outputting as a data. 2. A coordinate input device which, when a predetermined portion of an input surface is pressed, sequentially takes in coordinate data corresponding to the pressed position and outputs only valid data among the taken-in coordinate data. The moving distance between the second coordinate data and the third coordinate data, and the first coordinate data are sequentially taken using three pieces of coordinate data while taking in the coordinate data obtained by the handwriting input below at a fixed timing. And the linear axis between the second coordinate data and the linear axis between the second coordinate data and the third coordinate data are obtained, and the moving distance and the frequency of the angular change obtained individually are accumulated. Then, while referring to the cumulative frequency obtained thereby, a predetermined angle change reference value and a corresponding moving distance are set as threshold values for valid data determination. At the time of normal input operation, the movement between the second coordinate data and the third coordinate data is performed using the arbitrary coordinate data obtained during the writing and the two valid data input immediately before. The distance and the amount of angle change between the linear axis between the first coordinate data and the second coordinate data and the linear axis between the second coordinate data and the third coordinate data are calculated. A comparison is made with a threshold for determining valid data set by the initial setting process, and when at least one of the calculation results is within the threshold, the arbitrary coordinate data is output as valid data. A data processing method for a coordinate input device, wherein input data processing is performed.