JPH0962450A - Misdetection deciding method and information processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the processing speed fast and save the handling time to set a decision reference value by employing variables representing curvature and not the moving speed of a pen tip, but the moving acceleration for a judgement material for misdetection. SOLUTION: When an operator presses a pen tip against a touch panel, resistance films 303 and 304 comes into contact with each other at the position of the pen tip to conduct. The voltage level of the film 304 becomes equal to the voltage level at the conduction position of the film 303 as a result of the conduction. The film 303 which is applied with a voltage is uniform in area resistivity, so the voltage level at the conduction position is proportional to the distance from a ground-side electrode 307. For the purpose, the voltage level of the lead-out line 310 of the film 304 is measured to detect the (x)-axial position on the film 303 from the voltage level, the voltage applied to the film 303, and the area resistivity. Similarly, the (y)-axial position can be detected. The specific variable representing the moving acceleration of the pen tip is calculated from those values and this variable is compared with a specific upper-limit variable to decide misdetection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining erroneous detection of a touch panel for detecting a designated position for inputting a position to an information processing device, and an information processing device used for this implementation.

[0002]

2. Description of the Related Art A touch panel for detecting a specified position with a pen and inputting the detected position information to an information processing device has been widely adopted in recent years as a main input means of the information processing device because of its ease of operation. There is. The touch panel has two flat plate-like resistance films provided in parallel with each other at a minute interval. This specified position detection method for the touch panel causes a current to flow through only one film, and when the operator directly presses the pen tip to the position to be input, the two resistive films come into contact with each other to cause the other film to occur. Detect the voltage and read the specified position.

The information processing apparatus converts the input position information into coordinate values, samples the coordinate values at a constant time interval (sampling period), and calculates the distance between the sampled coordinate values (sample points). Looking for. Now, when inputting a continuous curve using the position input device described above, there are rare cases where the touch panel detects a position deviated from the trajectory of the pen tip as the designated position. This is because electronic equipment generally emits minute electromagnetic waves (hereinafter referred to as noise), and the resistance film for detecting voltage acts as an antenna and receives this electromagnetic wave, so that voltage is generated in this resistance film. This is because the designated position is erroneously read from this voltage.

By the way, a continuous curve input by an operator is characterized by a curvature representing a degree of curve of the curve and a moving speed of a pen tip appearing in a distance between sample points. That is, as the trajectory of the curve increases in complexity, its curvature increases, and as the moving speed of the pen tip increases, the distance between sample points increases. Further, since there is a limit to the human ability to input a continuous curve, the range of values that the curvature of the continuous curve can take is determined according to the moving speed of the pen tip. Therefore, in the conventional information processing apparatus, the curvature and the distance between the sample points are used as the determination material for determining the erroneous detection of the touch panel, and the curvature obtained from the sample points is set according to the moving speed of the pen tip. If it exceeds the range of, it is determined as false detection.

FIG. 4 shows the judgment standard of the conventional erroneous detection judgment method.
It is an explanatory view explaining. Points P1, P2, P3 in Fig. 4 (a)
All existed on the trail of the pen tip and were detected normally.
This is a sample point. Where most of the curves P1P2P3
The curvature at the point P2 where the rate becomes large is C_aAnd on the other hand,
When the pen tip is moved faster than in Figure 4 (a) in Figure 4 (b).
The detected sample points are shown. In the figure, points P4, P
5, P6 is the sample point detected by the touch panel
However, point P5 is a sample that was erroneously detected due to the influence of noise.
It is a pull point. The original sample point corresponding to point P5
The int is shown in the same drawing as point P5a. Where the curve P4
The curvature at the point P5 where the curvature of P5P6 is the largest is C_b,
Also, at the point P5a where the curvature of the curve P4P5aP6 is the largest,
Curvature C _cAnd the curvature C_bIs the curvature C_cGreater than
And Furthermore, as is clear from the shape of the curve, at point P2
Curvature C_aAnd the curvature C at point P5_bIs almost the same as
Shall be.

However, the curvature C_bPoint P5, which is the point of interest of
It is a sample point that was erroneously detected, and
It is possible that it is actually input at the trace moving speed
Yes. Therefore, as a judgment criterion, the pen tip in FIG.
For the moving speed, the curvature C _bIs judged as false detection and the curvature
C_cSet the upper limit of curvature so that is not detected as false detection
Of.

On the other hand, sample points in FIG. 4 (a)
If the erroneous detection of is determined based on the upper limit value, the curve P1P2P3
Curvature C at point P2 of_aIs the curvature C at point P5_bAnd about one
The point P2 that was normally detected and corresponds to point P5 is erroneously detected.
It is determined that the sample point has been issued. Therefore,
The curvature C with respect to the moving speed of the pen tip in FIG. _a
The upper limit of the curvature is C_aGreater than
Must be set to a certain value.

Generally, the trajectory of the pen tip that a human moves is
The faster the pen moves, the flatter it becomes. Therefore, when the distance between the sample points is long, the upper limit value of the curvature which is determined to be an erroneous detection is reduced according to the degree. On the contrary, if the distance between the sample points is short, that is, if the pen tip moving speed is slow, the trajectory may be complicated. Increase the upper limit.

FIG. 5 shows a processing procedure of a conventional erroneous detection determination method.
It is a flowchart shown. Before starting the process,
Threshold V for dividing the moving speed of the pen tip ₀,
The moving speed of the pen tip is the threshold value V₀For faster curvature
Upper limit value C_FAnd threshold V₀Upper limit of curvature in the following cases
C_S (C_S> C_F) Is set. Detected sample
Read the coordinates of the point (S601) and move speed V or song
Whether the coordinate data necessary to calculate the rate C are available
(S602), and if there is a shortage, coordinate data is
Store in the register (S603) and finish. Complete coordinate data
If it is, the moving speed V and the curvature C of the pen tip are calculated.
(S604,605). The moving speed V of the pen tip is the threshold value V₀Below
If there is (S606), this time the curvature C is the upper limit C_SLess than
It is determined whether or not (S607). The curvature C is the upper limit C_SLess than
If not, memorize the coordinates of the detected sample point and
Between the sample point of and the previous sample point
Draw a straight line (S608) and finish. In S607 the curvature C is
Upper limit value C_SIf it is above, the sample point is wrong.
When it is determined that it has been detected (S611), the process ends.

On the other hand, when the moving speed V is larger than the threshold value V ₀ in S606, it is judged whether or not the curvature C is smaller than another upper limit value C _F (S609). The curvature C is the upper limit value C _F
If it is smaller, the coordinates of the detected sample point are stored, a straight line is drawn between this sample point and the previous sample point (S610), and the process ends. If the curvature C is equal to or larger than the upper limit value C _{F in} S609, it is determined that the sample point is erroneously detected (S611), and the process ends.

[0011]

In the conventional erroneous detection determination method, the curvature and the moving speed of the pen tip are used as the determination material.
It is necessary to preset a threshold value for dividing the pen tip moving speed into a range and an upper limit value of the curvature at each moving speed divided by this threshold value. If the number of sections of the moving speed is increased in order to increase the accuracy of erroneous detection, the upper limit value of the curvature must be set for each of the divided moving speeds, which is troublesome. Further, since the position is input in real time, it is desired that the processing speed related to this is as fast as possible including the erroneous detection determination processing. However, in the conventional erroneous detection determination method, there is a problem that increasing the number of sections of the moving speed in order to improve the accuracy of erroneous detection causes a decrease in processing speed.

The present invention has been made in view of the above circumstances, and adopts a variable representing a moving acceleration instead of the curvature and the moving speed of the pen tip as a judgment material for erroneous detection.
Speeds up the processing speed and saves the trouble of setting the judgment reference value.

[0013]

In the erroneous detection determination method according to the present invention, a variable representing the moving acceleration of the position designating means is calculated from a plurality of sequentially designated positions, and the calculated variation exceeds a predetermined range. In this case, it is characterized that it is determined that the designated position is erroneously detected. This erroneous detection determination method determines that erroneous detection has occurred when the variable representing the movement acceleration of the position designating means exceeds a predetermined range because the motion of the position designating means follows the physical law.

The information processing apparatus according to the present invention further comprises a storage means for sequentially storing the detected designated positions, and a variable calculating means for calculating a variable representing the moving acceleration of the position designating means from the designated positions stored in the storage means. And a means for determining that the designated position is erroneously detected when the variate calculated by the variate calculating means exceeds a predetermined range. Since the movement of the position designating means follows the physical law, this information processing apparatus determines that an erroneous detection has occurred when the variable representing the moving acceleration of the position designating means exceeds a predetermined range.

FIG. 6 is a conceptual diagram showing a relationship between a locus drawn by a human using a pen and sample points at which the locus is sampled. In the figure, the positions of the sample points of the locus of the pen tip that are sequentially input are represented by a vector having O as an origin for associating with sample points before and after the sample points. That is, the n-th sample point sampled at the sampling period Δt is represented as a vector P (n). The vector P (n-1) represents the (n-1) th sample point, that is, the sample point sampled Δt before the time when the nth sample point was sampled. The vector P (n-2) also represents the (n-2) th sample point.

Now, letting the moving speed from the (n-1) th to the nth sample point be a vector V (n),
The vector V (n) can be expressed as follows using the vector P (n), the vector P (n-1) and Δt.

[0017]

[Equation 1]

Similarly, the moving speed from the (n-2) th to the (n-1) th sample point, the vector V (n-
1) can be expressed as follows.

[0019]

[Equation 2]

Further, if the moving acceleration from the (n-1) th to the nth sample point is a vector A (n), the vector A (n) is the moving speed V (n-1) at the (n-1) th sample point. , The moving speed V (n) at the nth sample point and Δt can be expressed as follows.

[0021]

(Equation 3)

This vector A (n) can be expanded from the equations 101 and 101a as follows.

[0023]

(Equation 4)

Further, the components of the vector P (n) are represented by {Px
(n), Py (n)}, the component of the vector A (n) is

[0025]

(Equation 5)

Therefore, the magnitude of the vector A (n) | A (n) |
Is

[0027]

(Equation 6)

Can be expressed as

According to the equation of motion, the magnitude of the lateral movement acceleration of the pen is proportional to the magnitude of the force applied in the lateral direction of the pen. However, there is a limit to the force that a human can apply to a pen. Therefore, there is a practical limit to the magnitude of the movement acceleration of the pen. That is, vector A
There is an upper limit on the size | A (n) | of (n).
If the upper limit value is A _max , the following inequality is established. │A (n) │ <A _max … 105

When the moving acceleration is calculated by using a computer, the ratio of the time required for the whole division calculating process and the square root calculating process to calculate the moving acceleration is large. Therefore, α (n) that satisfies the following equation is introduced for the convenience of processing speed in a computer. α (n) = (Δt) ² * | A (n) | ² ... 106 From equations 106 and 105, there is an upper limit for α (n). If this upper limit value is set to α _max , α (n) can be expressed by the following equations 104 and 106. α (n) = {Px (n) -2 * Px (n-1) + Px (n-2)} ² + {Py (n) -2 * Py (n-1) + Py (n-2)} ² <Α _max … 107

That is, the upper limit value α _max of α is set based on the limit of the force that a person can apply to the pen.
By comparing the magnitudes of α and α _max calculated from the input sample points, erroneous detection of the designated position is determined. Although a case has been described here where a variable representing the moving acceleration is used as the determination material, the moving acceleration itself may be used.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. There is an information processing apparatus equipped with a position input device having a position specifying means using a pen and a position detecting means using a transparent touch panel. Such an information processing device is provided on the rear surface of the touch panel.
An LCD is provided, and display is made so that the specified position on the touch panel and the display position on the LCD that is visible through the touch panel match. FIG. 1 is a block diagram of the information processing apparatus described above.

In the figure, 201 is a touch panel for detecting coordinates. Touch panel 201 is coordinate detection circuit 20
Connected to 2. The coordinate detection circuit 202 samples the coordinates detected by the touch panel 201 at a time interval of Δt and stores them in the x coordinate data register 203 or the y coordinate data register 204. When the coordinate data is stored in the x-coordinate data register 203 and the y-coordinate data register 204, an interrupt signal is generated for the CPU 205. The CPU 205 is connected to a main memory 209 that stores software that drives the CPU 205 and a video memory 207 that stores image data. The CPU 205 receives the interrupt signal and outputs the bit of the address of the video memory 207 corresponding to the coordinate data input. Turn on.

The LCD 206 is an aggregate of cells arranged in a grid on a plane, and each cell has an on state of black and an off state of white. LCD controller 208 is video memory
It is connected to 207 and LCD 206 and controls ON / OFF of LCD 206 according to ON / OFF state of the bit of video memory 207.

FIG. 2 is a schematic view of the touch panel 201 described above. In the figure, reference numerals 303 and 304 denote rectangular resistive films each having a uniform area resistivity, which are arranged in parallel at a minute interval. Resistive film 30 with the rectangular longitudinal direction lying
In 3 and 304, the upper left end is defined as the origin, and the coordinates are expressed with the right direction from the origin as the positive direction of the x-axis and the downward direction from the origin as the positive direction of the y-axis. The resistance films 303 and 304 are x
It is for detecting the axial direction and the y-axis direction.

The resistance film 303 has electrodes on both ends in the x-axis direction.
306 and 307 are provided, and a lead wire 311 for measuring the voltage of the resistance film is provided. A switch 315 and a DC power supply 308 are connected to the electrode 306, and the other electrode 30
7 is grounded. Similarly, the resistance film 304 is also provided with electrodes 312 and 313 at both ends in the y-axis direction and lead lines 310. Switch 316 and DC power supply 31 are attached to electrode 312.
4 is connected and the electrode 313 is grounded.

The coordinate detecting operation of the touch panel 201 described above is performed by alternately switching between two detecting modes of an x coordinate detecting mode and ay coordinate detecting mode for every minute time. That is,
A DC voltage is applied to the resistance film 303 in the x-coordinate detection mode, and a DC voltage is applied to the resistance film 304 in the y-coordinate detection mode.

That is, when the operator presses the pen tip on the touch panel, a DC voltage is applied to either one of the resistive films depending on the detection mode. Now, depending on the x-coordinate detection mode, the electrode 306 of the resistive film 303 and the electrode
It is assumed that a DC voltage from the DC power supply 308 is applied between the DC voltage and the voltage 307. When the operator presses the pen tip against the touch panel, the resistance film 303 and the resistance film 304 come into contact with each other at the position of the pen tip and become conductive. Due to conduction, the voltage level of the resistance film 304 becomes the voltage level at the conduction position of the resistance film 303. Since the resistance film 303 to which a voltage is applied has a uniform area resistivity, the voltage level at the conducting position is proportional to the distance from the ground side electrode 307. Therefore, if the voltage level of the lead wire 310 of the resistive film 304 is measured, the position in the x-axis direction on the resistive film 303 can be detected from this voltage level, the voltage applied to the resistive film 303, and the sheet resistivity.

In the y-coordinate detection mode, the electrodes 312, 313
A DC voltage from the DC power supply 314 is applied during this time, and similarly, this time, the position in the y-axis direction is detected from the voltage level of the resistance film 303.

The erroneous detection discriminating method according to the present invention uses the variable representing the movement acceleration of the pen shown in the equation 107 as the criterion. In order to apply the expression 107, the coordinate data of the latest sample points and the coordinate data of the sample points one cycle before and two cycles before are necessary.

FIG. 3 is a flowchart showing a continuous curve drawing processing procedure according to the erroneous detection discrimination method of the present invention. In this flowchart, the coordinate data of the latest sample point is (X _n , Y _n ). In addition, the coordinate data of the sample points one cycle before and two cycles before are (X
_n-1 , Y _n-1 ) and (X _n-2 , Y _n-2 ).

First, the coordinate data of the latest sample point is read (S401), and it is determined whether the latest coordinate data necessary for calculating α described later, the coordinate data of one cycle before, and the coordinate data of two cycles before are all available. It is determined (S402). Initially, since the coordinate data of two cycles before and the coordinate data of one cycle before do not exist, the latest coordinate data is stored in the register of the coordinate data of one cycle before ending. When processing this step next time, the coordinate data of one cycle before exists, but the coordinate data of two cycles before does not exist, so the coordinate data of one cycle before is stored in the register of the coordinate data of two cycles before. Then, the latest coordinate data is stored in the coordinate data register of one cycle before, and the process ends (S403).

As described above, the coordinate data is sequentially stored according to the input order, so that the coordinate data of one cycle before and the cycle of two cycles before necessary for calculating α are secured. If all coordinate data are available in S402, α is calculated from the following equation (S404). _{α = (X n -2 * X} n-1 + X n-2) 2 + (Y n -2 * Y
_n-1 + Y _n-2 ) ²

The magnitude of the calculated α and the upper limit value α _{max of} α, which is predetermined from the limit of human power, is compared, and α <α
_{If max} is satisfied, it is determined that the latest coordinate data has been normally detected (S405), and the coordinate data of one cycle before is 2
Store in the coordinate data register before the cycle. In addition, the latest coordinate data is stored in the coordinate data register of one cycle before (S407). Then, a straight line is drawn from the coordinate one cycle before on the LCD 206 to the latest coordinate (S408). On the other hand, in S405 α
If <α _max is not satisfied, it is determined that the latest coordinate data is due to an erroneous detection (S406), and the processing procedure is ended as it is. The above processing procedure is repeated to capture coordinate data and draw a continuous curve on the LCD 206.

Although the above embodiment has described in detail the case where the touch panel is used as the position input means, the present invention is not limited to the touch panel and can be similarly implemented with an electromagnetic induction type tablet or mouse. There is no end.

[0046]

As described above, conventionally, the moving speed and the curvature of the pen tip are calculated, the calculated moving speed is compared with the predetermined moving speed, and the upper limit of the predetermined curvature is divided for each moving speed. In the present invention, it is necessary to calculate a predetermined variable representing the moving acceleration of the pen tip and compare the magnitude of this variable with the upper limit value of the predetermined variable in the present invention. The number of steps can be reduced and the processing speed can be increased.

Further, in the conventional erroneous detection discrimination method, it was necessary to set the upper limit value of the curvature for each moving speed category.
In the present invention, only one upper limit value of a predetermined variable needs to be set. Furthermore, by adopting a variable corresponding to the movement acceleration of the pen tip and the one-to-one correspondence as the judgment material, it is possible to accurately separate the designated position by the pen tip and the designated position by noise. Furthermore, in the information processing apparatus of the present invention, the input information itself can be used as a clue to determine the input information due to erroneous detection. As described above, the present invention has an excellent effect in determining erroneous detection by the position detecting means.

[Brief description of drawings]

FIG. 1 is a block diagram of an information processing apparatus according to the present invention.

FIG. 2 is a schematic diagram of a touch panel.

FIG. 3 is a flowchart showing a processing procedure according to the present invention.

FIG. 4 is an explanatory diagram illustrating a determination standard of a conventional erroneous detection determination method.

FIG. 5 is a flowchart showing a processing procedure of a conventional erroneous detection determination method.

FIG. 6 is a conceptual diagram showing a relationship between a locus and sample points.

[Explanation of symbols]

 201 Touch panel 202 Coordinate detection circuit 203 x coordinate data register 204 y coordinate data register 205 CPU 206 LCD

Claims (2)

[Claims] 1. An erroneous detection discriminating method for discriminating that a designated position has been erroneously detected from a shift of the designated position detected by a position detecting unit that detects a designated position by a position designating unit that designates a position to be input. An erroneous detection determination method characterized in that a variable representing the moving acceleration of the position designating means is calculated from a plurality of detected designated positions, and if the calculated variable exceeds a predetermined range, it is determined that the designated position is erroneously detected. . 2. An information processing apparatus having position detecting means for detecting a specified position by a position specifying means for specifying a position to be inputted, and processing the specified position detected by the position detecting means as input information. A storage unit that sequentially stores designated positions, a variable calculation unit that calculates a variable representing the moving acceleration of the position designation unit from the designated positions stored in the storage unit, and a variable calculated by the variable calculation unit within a predetermined range. An information processing apparatus, comprising: means for determining that the designated position has been erroneously detected when the number of points exceeds.