JPH11296291A - Writing implement type coordinate input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct an error due to a change in the attitude of a writing implement type coordinate input device though the tip of the device is stopped on a writing plane or an error included in a displacement time measuring means such as an acceleration sensor and to improve the accuracy of calculation for the locus of the device tip. SOLUTION: The input device is provided with a contact state judging means 30 for judging a state that the tip of the input device is brought into contact with a writing plane but is not moving and an operation means 41 for correcting an error included in the displacement time measuring time 10 such as an acceleration sensor so that the moving distance of the device tip becomes zero.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a computer,
A writing implement that belongs to the class of writing implement type coordinate input devices used to input the coordinates of handwritten characters and figures written on a two-dimensional plane, and in particular, does not require a dedicated writing plane to obtain the trajectory of the device tip The present invention relates to a type coordinate input device.

[0002]

2. Description of the Related Art A special input board such as a tablet is not required for inputting coordinates on a two-dimensional plane XY.
Conventionally, as a device for obtaining coordinates only with a writing instrument type coordinate input device, an acceleration sensor for detecting acceleration in the X-axis and Y-axis directions is arranged on the writing instrument, the acceleration of the writing instrument is detected, and the acceleration is time-integrated twice. A device for obtaining coordinates has been proposed.

A method for detecting that the tip of a writing instrument type coordinate input device is in contact with a writing plane due to the presence of a high frequency component among the frequency components included in the signal detected by the acceleration sensor is disclosed. Kaihei 7-200127
Are disclosed.

As a method for judging contact between the tip of the writing instrument type coordinate input device and the writing plane, a microswitch is attached to the base end of the core connected to the tip of the writing instrument type coordinate input apparatus, and the microswitch is brought into contact with the writing plane. There is also known a method of turning on a micro switch when writing pressure is applied.

[0005]

According to the above-mentioned prior art, the output of an acceleration sensor mounted on a writing instrument type coordinate input device is processed depending on whether its tip is in contact with a writing plane or not. can do.

For example, after the tip of a writing instrument type coordinate input device is brought into contact with a writing plane and moved so as to draw a single line,
Move away from the writing plane, move it in the air to the position where you want to write the next line you want to write, and touch the writing plane again at that position to draw a line.If you draw a line, the tip of the writing instrument type coordinate input device obtained from the acceleration sensor output Can be distinguished into a trajectory in the air and a trajectory on a writing plane.

[0007] However, the distinction was insufficient.

When writing, a human is (a) an operation of placing the tip of a writing instrument type coordinate input device on a writing plane, (b) an operation of moving the tip of the writing instrument type coordinate input apparatus on a writing plane, and (c) writing tool type coordinate input. Operation to move the tip of the writing device away from the writing plane. (D) Operation to move the tip of the writing instrument type coordinate input device in the air.

In particular, in the operations (a) and (c), although the tip of the writing instrument type coordinate input device is stopped by contacting the writing plane, the posture of the writing instrument type coordinate input device is complicated by the force applied by the finger. Since it is changing, the displacement time change measuring means outputs an output corresponding to the acceleration or the like caused by the posture change unless it is attached to the tip of the writing instrument type coordinate input device. Therefore, when the operations (a) and (c) are not strictly distinguished from other operations as in the prior art, the trajectory calculating means outputs the output of the displacement time change measuring means due to the posture change to the writing tool type coordinate input. There is a problem of calculating as a movement locus of the tip of the device.

This problem will be specifically described with reference to a conventional example.

The technique disclosed in Japanese Patent Application Laid-Open No. Hei 7-200127 is based on the writing instrument type coordinate system which is generated by friction with the writing plane when the writing instrument type coordinate input device is moved on the writing plane. This is to detect a state in which the input device is in contact with the writing plane.

Due to the principle of generation, the high frequency component of the acceleration does not occur when the tip of the writing instrument type coordinate input device is placed on the writing plane, but is generated when the writing instrument type coordinate input apparatus is moved on the writing plane. Therefore, this means that only the writing operation (b) is detected. In this case, the trajectory of the handwritten character or the figure is determined from the output signals of the acceleration sensor or the like during the determination of the operation (b).
(C) and (d) are not distinguished), and a writing implement changes from a part constituting a character or a figure to a part constituting another character or a figure from an output signal of an acceleration sensor or the like during the determination. Is moving in the air.

Therefore, the output of the acceleration sensor due to the posture change in the operations (a) and (c) is processed as trajectory information for moving the tip of the writing instrument type coordinate input device in the air, and becomes the trajectory in the air. There was a problem that included errors.

In a conventional example in which a microswitch is attached to the base end of a core connected to the tip of a writing instrument type coordinate input device, the micro switch is not connected between the writing tool and the writing plane. That is, operation (a),
While (b) and (c) are performed, all outputs from the acceleration sensor and the like are processed as trajectories of characters and figures, so that there is a problem that trajectories of characters and figures include errors.

On the other hand, in such an apparatus, if the output of the acceleration sensor is integrated over time without correcting for the error included in the output of the displacement time change measuring means for a long time, the error of the calculated trajectory becomes very large. It is known. MIT's ChrisVerplaetse reports that the acceleration contains only 0.001 G of error, and if integrated for 300 seconds without error correction, the final trajectory error can be as much as 441 m.
That is, in order to realize a writing instrument type coordinate input device used for inputting coordinates such as handwritten characters and figures, it is necessary to correct an error included in the output of the displacement time change measuring means at small time intervals. There were challenges.

[0016]

In order to achieve the above-mentioned object, according to the present invention, the contact state between the tip of the writing instrument type coordinate input device and the writing plane is expressed as follows: The tip of the writing instrument type coordinate input device is not in contact with the writing plane.

(2) The tip of the writing instrument type coordinate input device is in contact with the writing plane, and the tip of the writing instrument type coordinate input apparatus does not move on the writing plane.

(3) The tip of the writing instrument type coordinate input device is in contact with the writing plane, and the tip of the writing instrument type coordinate input apparatus is moving on the writing plane.

The present invention is characterized in that it comprises a contact state determining means for determining any one of the states.

That is, the contact state determining means determines that the contact state at the time of the operation (d) is (1) and the operation (a)
The contact state in (c) is determined as (2), and the contact state in operation (b) is determined as (3).

From the output of the displacement time change measuring means in the state (1), the writing implement is moved in the air from a part constituting a character or a figure to a part constituting another character or a figure. By calculating the trajectory and calculating the trajectory of the handwritten character or the figure from the output of the displacement time change measuring means in the state (3), each calculation result does not include an error caused by the state (2). Can be

In this case, as in the third aspect of the present invention, the trajectory calculating means temporarily stores the output of the displacement time change measuring means and the judgment result of the contact state judging means as data, And calculating means for correcting the output of the displacement time change measuring means so that the moving distance of the tip of the writing instrument type coordinate input device calculated based on the output of the displacement time change measuring means becomes zero in the case of 2). Is included in the output of the displacement time change measuring means in accordance with the occurrence of the state (2), that is, the physical phenomenon that the tip of the writing instrument type coordinate input device is stopped on the writing plane. Can be corrected. This is because, for example, when writing a kanji, every time a stroke constituting the kanji is written, the state (2) occurs twice at the start and end of the writing, so that correction at sufficiently fine time intervals is performed. It has become.

[0023] Here, as in the invention according to claim 4, the trajectory calculating means switches the determination result of the contact state determining means to the state (2) or the timing at which the determination result switches from the state (2). When the transfer means for transmitting the data to the calculation means is provided, the transferred data always includes the state (2). The error included in the output can be corrected, and the memory can be configured with a small-capacity storage unit.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below.

The present embodiment is a writing instrument type device for inputting motion information of the tip of the device to a computer (not shown). Specifically, it is a device for digitally processing the trajectory of the tip of the device when writing a symbol, character, or figure and inputting it to a computer as coordinates of continuous points. Based on the coordinate information output from this device, if the locus is reproduced on the monitor screen using a computer, characters and figures can be handwritten while checking the writing state on the monitor screen. Even people who are unfamiliar with the operation of the computer will be able to use the computer.

For the following description, first, terms are defined using FIG. In the following description, the term “tip” refers to the lower end face of FIG. 1 and the “proximal end” refers to the upper end face. The writing plane is a plane parallel to a plane extending along the coordinate axes x and y axes shown in the drawing. In this figure, for the sake of explanation, the writing tool type coordinate input device is written so as to be perpendicular to the writing plane, but the relationship between the writing tool type coordinate input device and the writing plane is limited to vertical. Not something.

The writing instrument type coordinate input device according to the present embodiment will be described first with reference to FIG.

The present apparatus has an outer case 1 shaped like a writing implement made of plastic or the like.

The tip of the writing core 2 is exposed from the tip of the outer case 1. Therefore, the tip of the writing core 2 is the tip of the writing instrument type coordinate input device.

The writing core 2 may be formed of plastic or the like which does not leave writing marks on the writing plane, but it is better to use the same one as the ballpoint pen shaft or pencil core. This is more preferable because the written trace actually remains on the writing plane and the user can confirm the written content without going through the monitor screen of the computer.

At the base end of the outer case 1 is attached a cable 3 for communication with a computer (not shown). However, the communication method is not limited to the wired method. The wireless method is more preferable because the cable does not obstruct the movement of the writing instrument.

Further, a function closer to the existing writing implement, such as attaching a non-slip rubber member or performing antibacterial processing, may be added to a portion of the outer case 1 gripped by a finger.

Next, the inside will be described.

First, a displacement time change measuring means 10 is provided inside the outer case 1 at a position as close to the front end as possible inside the writing instrument type coordinate input device of this embodiment.

The displacement time change measuring means 10 includes:
At least an acceleration sensor 11 for detecting accelerations in two orthogonal directions in a writing plane is provided. This is 2
One-dimensional acceleration sensor module may be used,
Two one-dimensional acceleration sensors may be arranged and arranged such that their sensitivity axes are substantially orthogonal to each other. In addition, an acceleration sensor for detecting an acceleration in an axial direction, an inclination sensor 12 for measuring an inclination of a writing implement when writing, Japanese Patent Laid-Open No. 6-677.
An angular velocity sensor 13 for detecting the rotation of a writing instrument as disclosed in Japanese Patent Application Laid-Open No. H5-299.
If a second set of acceleration sensors for detecting accelerations in two orthogonal directions in a writing plane for calculating the inclination of the writing instrument, as disclosed in 30886, is mounted, the trajectory calculation means 40 described later This is preferable because the accuracy of calculating the trajectory of the tip of the mold coordinate input device is higher.

Further, the displacement time change measuring means 10 can have the same function as long as it is attached to the outer case 1, so if there is not enough space for installation,
A part or the whole may be exposed to the outside of the outer case 1. However, even in this case, it is desirable to provide the displacement time change measuring means 10 as close to the tip as possible so that the tip acceleration can be measured as accurately as possible when the writing instrument type coordinate input device is tilted.

The tip contact measuring means 20 includes a high-frequency component separating means 220 for separating high-frequency components contained in a detection signal of the acceleration sensor 11 and a push-type micro switch 211 shown in FIG. 2 is provided with physical contact detection means 210 for detecting that the tip of the writing implement type coordinate input device arranged at the base end of the writing tool 2 is physically in contact with the writing plane. In the physical contact detecting means 210, when the tip of the writing instrument type coordinate input device is placed on the writing plane, a reaction force from the writing plane is applied to the writing core 2 and the microswitch 211 is turned on to increase the voltage to + 5V. When the tip of the writing instrument type coordinate input device is separated from the writing plane, there is no reaction force from the writing plane to the writing core 2 and the microswitch 211 is turned off, so that 0V is applied to the contact state determination means 30 described later. Output.

Here, if the stroke of the push portion of the microswitch 211 is long, when the tip of the writing instrument type coordinate input device is placed on a writing plane, the writing core 2 is attached to the outer case 1.
It is preferable to use a shorter one because it moves so as to be pushed into the inside and the user feels unnatural.

Also, when the micro switch 211 is turned on or
If the FF can be determined, voltages such as +5 V and 0 V are not particularly particular.

As another configuration, a configuration is used in which a pressure sensor is used, an appropriate threshold is provided for the output, and whether or not the tip of the writing core 2 physically contacts the writing plane is detected from the pressure. You may do it.

Next, the high frequency component separating means 220 will be described with reference to the block diagram shown in FIG.

The analog output from the displacement time change measuring means 10 is amplified to a required level by an amplifier (not shown), and then only the output of the acceleration sensor is branched into two, one of which is sent to the high frequency component separating means 220. Is entered. Here, first, the high-pass filter 221 configured to pass a high-frequency component of about 60 Hz or higher extracts a high-frequency component of acceleration generated by friction with the writing plane when the writing tool is moved on the writing plane.
Then, the monostable multivibrator 222 using the high-frequency component of the acceleration as a trigger input generates a signal shaped as +5 V when the high-frequency component of the acceleration exists and 0 V when the high-frequency component does not exist. Output to 30.

Also in this case, if it can be determined whether a high frequency component exists or not, voltages such as +5 V and 0 V are not particularly limited.

The other one of the branched acceleration sensor outputs and the other sensor output are converted into digital values by an analog / digital converter 50 having a sampling interval ΔT at a certain interval, and then the trajectory calculation described later is performed. Means 40
Sent to

The contact state determining means 30 will be described with reference to FIG.

The contact state judging means 30 outputs a 2-bit digital value to a locus calculating means 40, which will be described later, by a combination of the output + 5V, 0V of the micro switch 211 and the output + 5V, 0V of the monostable multivibrator 222. (1) The tip of the writing instrument type coordinate input device and the writing plane are not in contact with each other.

(2) The tip of the writing instrument type coordinate input device is in contact with the writing plane, and the tip of the writing instrument type coordinate input apparatus does not move on the writing plane.

(3) The tip of the writing instrument type coordinate input device is in contact with the writing plane, and the tip of the writing instrument type coordinate input apparatus is moving on the writing plane.

Any one of the states is determined and a digital value is output.

The combination of logic is as follows. When the output of the microswitch 211 is 0 V and the output of the monostable multivibrator 222 is 0 V, the tip of the writing instrument type coordinate input device is separated from the writing surface and the writing instrument does not move on the writing plane.
(1) It is determined that the tip of the writing instrument type coordinate input device is not in contact with the writing plane, and two bits “00” are output.
Also, the output of the microswitch 211 is + 5V, and
The output of the monostable multivibrator 222 is 0 V
In the case of (1), since the tip of the writing instrument type coordinate input device is on the writing surface and the writing instrument does not move on the writing plane, (2) the tip of the writing instrument type coordinate input device contacts the writing plane, Further, it is determined that the tip of the writing instrument type coordinate input device has not moved on the writing plane, and two bits of “10” are output. Then, the output of the micro switch 211 is +5
When the output is V and the output of the monostable multivibrator 222 is +5 V, the tip of the writing instrument type coordinate input device is on the writing surface, and the writing instrument is moving on the writing plane. It is determined that the tip of the coordinate input device is in contact with the writing plane and the tip of the writing instrument type coordinate input device is moving on the writing plane, and outputs two bits of “11”.

Here, the output method of the contact state determination means 30 is not limited to the above.

The trajectory calculating means 40 will be described with reference to FIG.

The trajectory calculation means 40 comprises a microcomputer as the calculation means 41, a memory as the storage means 42, and an electronic circuit as the transfer means 43.

In the operation, first, the memory stores the determination result and the digital value of the output from the displacement time change measuring means 10 as data. At this time, it is necessary to mount a memory having a sufficient capacity according to the data amount so that the data does not overflow from the memory.

Then, the electronic circuit transfers the data to the microcomputer each time the state (2) of the determination result appears. That is, the electronic circuit switches from the state (1) or (3) of the determination result to the state (2), or switches from the state (2) of the determination result to the state (1) or (3). The data is transferred to the microcomputer using the edge as a trigger.

The microcomputer to which the data has been transferred performs the following preprogrammed processing.

[1] The time integration of the output of the acceleration sensor is performed twice to calculate the trajectory of the portion of the exterior case 1 where the acceleration sensor 11 is attached. Incidentally, the time interval of this time integration is the sampling period ΔT.

[2] When the inclination sensor 12 is attached, the inclination amount of the writing instrument type coordinate input device is calculated from the inclination sensor 12, and when the angular velocity sensor 13 is attached, the output is output. On the other hand, one time integration is performed to calculate the rotation amount of the writing instrument type coordinate input device.

[3] The acceleration sensor 11 in the outer case 1
Is performed on the trajectory of the portion where is attached, based on the amount of tilt and the amount of rotation, to determine the trajectory of the tip of the writing core 2.

[4] Comparing the determination result in each sampling period ΔT with the trajectory of the tip of the writing core 2,
The trajectory of the tip of the writing lead 2 during the period in which the determination result is state (2) is selected.

[5] The moving distance of the locus of the tip of the selected writing core 2 is checked, and a difference from zero is regarded as an error. Then, the data transferred to the microcomputer is corrected so that the moving distance of the trajectory of the tip of the writing core 2 becomes zero.

After the above processing, the corrected writing core 2
Is sent to a computer (not shown) through the cable 3 by communication means (not shown). Therefore, if a locus handwritten from the coordinate data is reproduced and displayed on a monitor screen, and a program for recognizing the content is executed in the computer, the computer can be operated without using a keyboard. become able to.

Here, the trajectory calculating means 40 may be realized in the form of software that operates on a computer (not shown) without being disposed in the outer case 1 at all.

[0064]

According to the first and second aspects of the present invention, the writing implement is moved in the air from a portion forming a character or a figure to a portion forming another character or a figure. The tip of the writing instrument type coordinate input device and the writing plane are in contact with the trajectory and the calculation result of the trajectory of the written handwritten character or figure, and the tip of the writing instrument type coordinate input device does not move on the writing plane. The error caused by the state can be prevented from being included.

Further, according to the third aspect of the present invention, an error included in the output of the displacement time change measuring means can be corrected in accordance with a physical phenomenon occurring at sufficiently small intervals.

Further, according to the fourth aspect of the present invention, the error contained in the output of the displacement time change measuring means can be reliably corrected by the storage means having a small capacity.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a writing instrument type coordinate input device of the present invention.

FIG. 2 is a block diagram of a writing instrument type coordinate input device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer case 2 Writing core 3 Cable 10 Displacement time change measuring means 11 Acceleration sensor 12 Inclination sensor 13 Angular velocity sensor 20 Tip contact measuring means 210 Physical contact detecting means 211 Micro switch 220 High frequency component separating means 221 High pass filter 222 Monostable Multivibrator 30 contact state determination means 40 trajectory calculation means 41 calculation means 42 storage means 43 transfer means 50 analog / digital converter

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[Procedure amendment]

[Submission date] June 7, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

The present invention is characterized in that a contact state determining means for determining any one of the states is provided.

Claims (4)

[Claims] 1. A writing instrument type coordinate input device, comprising: a displacement time change measuring means constituted by a sensor group including an acceleration sensor for detecting acceleration in at least two orthogonal directions in a writing plane; A tip contact measuring means for measuring a contact state between a tip and a writing plane, wherein a contact state between the tip of the writing instrument type coordinate input device and the writing plane is determined by: (1) a tip and a writing plane of the writing instrument type coordinate input apparatus; Is not in contact with (2) The tip of the writing instrument type coordinate input device is in contact with the writing plane, and the tip of the writing instrument type coordinate input apparatus does not move on the writing plane. (3) The tip of the writing instrument type coordinate input device is in contact with the writing plane, and the tip of the writing instrument type coordinate input apparatus is moving on the writing plane. A writing state coordinate input device comprising: a contact state determination unit that determines any one of the states. 2. A tip contact measuring means for separating a high frequency component included in a detection signal of the acceleration sensor from a high frequency component, and a tip of the writing instrument type coordinate input device and a writing plane are brought into physical contact with each other. 2. A writing instrument type coordinate input device according to claim 1, further comprising: physical contact detection means for detecting that the user is touching. 3. A trajectory calculating means for calculating a moving distance of a tip of a writing implement type coordinate input device, wherein the trajectory calculating means calculates an output of the displacement time change measuring means and a determination result of the contact state determining means. A storage means for temporarily storing data, and an operation for correcting the output signal of the displacement time change measuring means so that the moving distance of the tip of the writing instrument type coordinate input device becomes zero when the judgment result corresponds to the state (2). 2. The writing instrument type coordinate input device according to claim 1, further comprising means. 4. The trajectory calculating means includes a transfer means for sending the data to the arithmetic means at a timing when the determination result of the contact state determining means switches to the state (2) or at a timing when the determination result switches from the state (2). The writing instrument type coordinate input device according to claim 3, further comprising: