JP3712835B2 - Pen-type input device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pen-type input device for inputting written figures and characters.
[0002]
[Prior art]
As an input device such as a computer device, for example, a keyboard, a mouse, a digitizer, a light pen, a tablet, and the like are used. With the downsizing of computer devices, needs for portable terminal devices are increasing and users are increasing year by year. Therefore, a small input device has been demanded.
[0003]
There is a limit to the miniaturization of the keyboard in terms of a human interface, and it is not practical as an input device for a portable terminal device. Although the mouse can be miniaturized as a pointing device, it is not suitable for inputting figures and characters.
[0004]
For this reason, many pen-type input devices using a tablet and a pen are employed as input devices for portable terminal devices. When the pen-type input device using the tablet is further reduced in size, the size of the tablet becomes a problem. Therefore, for example, a pencil-type input device described in Japanese Patent Laid-Open No. 6-230886, a pen-type computer input device described in Japanese Patent Laid-Open No. 6-67799, and a pen-type input device disclosed in Japanese Patent Laid-Open No. 3-156519. Computer input devices have been developed.
[0005]
In the pencil type input device described in Japanese Patent Laid-Open No. 6-230886, after integrating the outputs of the two sets of acceleration sensors, the influence of the mounting position of the acceleration sensors is corrected, and the movement direction and movement amount of the pen tip are determined. Detected. Further, in the pen-type computer input device disclosed in Japanese Patent Application Laid-Open No. 6-67799, the direction and amount of movement of the input device are examined based on the signals from the two acceleration sensors, and the piezoelectric vibration gyro signal is used as the basis. The effect of rotation of the input device on the movement direction and movement amount detected by the acceleration sensor is detected, and the movement direction and movement amount are corrected. Further, the pen-type computer input device disclosed in Japanese Patent Laid-Open No. 3-156519 has two acceleration sensors and a pressure sensor at the pen tip, and is orthogonal to the pen axis based on the outputs of the two acceleration sensors. Detect acceleration in two directions orthogonal to each other in the plane to detect, detect that the pen tip is pressed against the writing plane based on the output of the pressure sensor, and press the pen tip against the writing plane Based on the outputs of the two acceleration sensors at the time of detection, the movement direction and movement amount are calculated in the pen tip.
[0006]
[Problems to be solved by the invention]
However, in the case of recognizing characters or the like input based on physical quantities such as acceleration at the pen tip, the pen tip is in contact with the writing surface but is stationary (such as a corner portion of the input character). In some cases, the pen tip portion is separated from the writing surface but is in a moving state. The pencil type input device described in the above-mentioned Japanese Patent Laid-Open No. 6-230886 and published in Japanese Patent Laid-Open No. 6-67799 In any of the pen-type computer input devices, the recognition rate of characters and the like in such a case is reduced.
[0007]
In the pen-type computer input device disclosed in Japanese Patent Laid-Open No. 3-156519, the pen tip is based on the outputs of the two acceleration sensors when it is detected that the pen tip is pressed against the writing plane. Since the movement direction and movement amount are calculated in the part, the pen tip part is separated from the writing surface but the moving state can be detected, but the pen tip part is in contact with the writing surface but is stationary. The state cannot be detected accurately, leading to a decrease in the recognition rate of characters and the like.
[0008]
In addition, when recognizing characters or the like input based on physical quantities such as acceleration at the pen tip, noise is generated from the impact when the pen tip touches the writing surface and when the pen tip moves away from the writing surface. May occur, and similarly the recognition rate of characters and the like is reduced.
[0009]
The present invention has been made to eliminate such disadvantages, and an object thereof is to improve the recognition accuracy of characters and the like.
[0010]
[Means for Solving the Problems]
The pen-type input device according to the present invention is a pen-type input device for performing writing input, and includes a pressure-sensitive sensor, an acceleration sensor, and a calculation unit, and the pressure-sensitive sensor detects pressure from a writing surface applied to the pen tip portion. The acceleration sensor detects the acceleration of the pen axis coordinate system, the calculation unit includes a contact detection unit, a friction detection unit, a state detection unit, and a writing calculation unit, and the contact detection unit outputs from the pressure sensor. The pressure signal to be determined is compared with a predetermined threshold value to determine whether the pen tip and the writing surface are in a non-contact state or a contact state, and the friction detection unit detects in advance the high-frequency component of the acceleration signal output from the acceleration sensor and Comparing with a predetermined threshold value to determine whether or not the pen tip and the writing surface are rubbing, and after the state detection unit determines that the pen tip has contacted the writing surface by the contact detection unit, the friction detection First of the nib and writing surface in the department The acceleration signal output from the acceleration sensor until the frictionless state is detected, and after the pen tip is not in contact with the writing surface, the friction detection unit detects the final frictionless state between the pen tip and the writing surface. Going back until detection, the acceleration signal output from the acceleration sensor is determined as noise, and the writing operation unit excludes the portion determined as noise by the state detection unit from the acceleration signal output from the acceleration sensor. An input character or the like is recognized by a low frequency component of the signal.
[0011]
Another pen-type input device according to the present invention is a pen-type input device that performs handwriting input, and includes an acceleration sensor and a calculation unit. The acceleration sensor detects acceleration in a pen axis coordinate system, and the calculation unit detects friction. A friction time measuring unit, a state detection unit, and a writing calculation unit, and the friction detection unit compares the high frequency component of the acceleration signal output from the acceleration sensor with a predetermined threshold value and the pen tip and the writing surface. The friction time measuring unit measures the duration of the state where the friction detection unit determines that the pen tip and the writing surface are rubbing, and the state detection unit The friction duration time measured by the friction time measuring unit is compared with a predetermined threshold value to determine whether the acceleration signal output from the acceleration sensor is noise or not, and the writing operation unit outputs from the acceleration sensor Acceleration And recognizes the input character or the like by the low frequency components of the signals except the portion determined as noise by the state detection unit from the signal.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The pen-type input device of the present invention is for inputting characters, symbols, figures, etc. to a computer device, etc., in particular by detecting the case where the pen tip is in contact with the writing surface and is stationary, Further, the recognition rate of characters and the like is improved by detecting noise generated from the impact when the pen tip is brought into contact with the writing surface and when the pen tip is separated from the writing surface.
[0015]
The pen-type input device includes, for example, an acceleration sensor, a pressure sensitive sheet, and a calculation unit. The acceleration sensor outputs a signal (hereinafter referred to as “acceleration signal”) indicating acceleration in the Xs axis direction, the Ys axis direction, and the Zs axis direction in a coordinate system (Xs, Ys, Zs) having the pen axis as the Zs axis, for example. . The pressure sensitive sheet detects the pressure from the writing surface applied to the pen tip, and outputs a signal indicating the pressure (hereinafter referred to as “pressure signal”). The calculation unit includes, for example, an input processing unit, a contact state determination unit, and a writing calculation unit. The input processing unit includes an AD converter, a high-pass filter (hereinafter referred to as “HPF”), and a low-pass filter (hereinafter referred to as “LPF”), and digitally converts the acceleration signal from the acceleration sensor and the pressure signal from the pressure-sensitive sheet. Then, a high frequency component or a low frequency component is extracted from the signal after digital conversion. This is because the component due to friction between the pen tip and the writing surface appears in the high frequency portion of the acceleration signal from the acceleration sensor, and the component due to movement of the pen tip appears in the low frequency portion of the acceleration signal from the acceleration sensor. is there. The contact state determination unit includes a contact detection unit, a friction detection unit, and a state detection unit. The contact detection unit compares the pressure signal from the pressure-sensitive sheet after digital conversion with a predetermined threshold value, and detects whether the pen tip portion and the writing surface are in contact with each other. The friction detection unit compares the high frequency component of the signal from the acceleration sensor with a predetermined threshold value, and detects whether or not the pen tip portion and the writing surface are rubbing. The state detection unit detects whether the pen tip portion and the writing surface are in contact with each other based on the detection result of the contact detection unit and the detection result of the friction detection unit, and whether or not it is stationary. The writing operation unit recognizes characters input by writing based on the acceleration based on the signal output from the acceleration sensor and the detection result of the state detection unit.
[0016]
Further, the state detection unit of the pen-type input device detects when the pen tip part and the writing surface come into contact with each other and when the pen tip part and the writing surface leave based on the detection result of the contact detection unit and the detection result of the friction detection unit. It is also possible to detect and remove noise generated from the impact when the pen tip portion and the writing surface are in contact with each other and when the pen tip portion and the writing surface are separated.
[0017]
【Example】
FIG. 1 is a block diagram of a pen-type input device 1 according to an embodiment of the present invention. As shown in the figure, the pen-type input device 1 includes acceleration sensors 2 a, 2 b, 2 c, a pressure sensitive sheet 3, a calculation unit 4, a storage unit 5, and a communication unit 6. The acceleration sensors 2a, 2b, and 2c output acceleration signals in the Xs axis direction, the Ys axis direction, and the Zs axis direction of the pen axis coordinate system (Xs, Ys, Zs) with the pen axis 8 as the Zs axis. The pressure-sensitive sheet 3 is configured, for example, by stacking two conductive rubbers, and outputs a pressure signal from a writing surface (not shown) applied to the pen tip portion 7.
[0018]
As shown in FIG. 2, the calculation unit 4 includes an input processing unit 41, a contact state determination unit 42, and a writing calculation unit 43. The input processing unit 41 includes AD converters 44a and 44b, an HPF 45, and an LPF 46. The AD converter 44a digitally converts an analog pressure signal applied to the pen tip 7 from the pressure sensitive sheet 3. The AD converter 44b digitally converts analog acceleration signals from the acceleration sensors 2a, 2b, and 2c (in the figure, the acceleration sensors 2a, 2b, and 2c are collectively represented by reference numeral 2). The HPF 45 extracts a high frequency component from the acceleration signal after digital conversion. The LPF 46 extracts a low frequency component from the acceleration signal after digital conversion.
[0019]
The contact state determination unit 42 includes a contact detection unit 47, a friction detection unit 48, and a state detection unit 49. The contact detection unit 47 compares the pressure signal from the pressure-sensitive sheet 3 after digital conversion with a predetermined threshold value, and detects whether the pen tip unit 7 and the writing surface are in contact with each other. Here, for example, when an L-shape is drawn as shown in FIG. 3, when the pressure signal D from the pressure-sensitive sheet 3 changes between approximately 1V and 0V as shown in FIG. Is defined as 0.5V. The contact detection unit 47 determines that the pen tip portion 7 and the writing surface are not in contact with each other when the pressure signal D from the pressure sensitive sheet 3 is less than 0.5 V, and the pressure signal D from the pressure sensitive sheet 3 is 0.5. When it is V or more, it is determined that the pen tip portion 7 and the writing surface are in contact.
[0020]
The friction detection unit 48 compares the high frequency components of the acceleration signals from the acceleration sensors 2a, 2b, and 2c with a predetermined threshold value, and detects whether or not the pen tip portion 7 and the writing surface are rubbing. This is because the high frequency components of the acceleration signals output from the acceleration sensors 2a, 2b, and 2c are mostly due to friction between the pen tip portion 7 and the writing surface. Here, for example, a high frequency component of the acceleration signal from the acceleration sensors 2a, 2b, and 2c at a certain time t when an L-shape is drawn as shown in FIG. 3 is represented by v (t). The difference value {v (t + 1) −v (t)} between the high frequency component of the acceleration signal at a certain time t and the high frequency component of the acceleration signal at the next sampling time t + 1 (the waveform in FIG. ) Is changed, for example, between approximately 1V and −1V, the threshold value is determined to be 0.1V or more. When the difference value {v (t + 1) −v (t)} is 0.1 V or more, the friction detection unit 48 determines that the pen tip portion 7 and the writing surface are in friction, and the difference value {v ( When t + 1) −v (t)} is less than 0.1 V, it is determined that the pen tip portion 7 and the writing surface are not rubbed.
[0021]
Based on the detection result of the contact detection unit 47 and the detection result of the friction detection unit 48, the state detection unit 49 determines whether or not the pen tip portion 7 and the writing surface are in contact with each other and is in a stationary state. To detect. For example, in FIG. 4, there are three places where the pen tip portion 7 and the writing surface are in contact with each other and in a stationary state. This is a writing start portion A, an L-shaped corner portion B, and a writing end portion C. For example, the length corresponding to the corner portion B of the L-shape differs depending on the writer, and the conventional pen-type input device has caused a reduction in the recognition rate. On the other hand, the pen-type input device according to the present invention can accurately recognize the corner portion B of the L character, so that the recognition rate of input characters and the like can be improved. Here, the moving state and the stationary state include both a state in which the pen tip portion 7 is in contact with the writing surface and a state in which the pen tip portion 7 is separated from the writing surface. Is in a state where the pen tip portion 7 is moving while in contact with the writing surface.
[0022]
Further, the state detection unit 49 determines whether the pen tip unit 7 and the writing surface until the first friction-free state after the pen tip unit 7 contacts the writing surface based on the detection result of the contact detection unit 47 and the detection result of the friction detection unit 48. When the pen tip part 7 is separated from the writing surface until the last friction-free state is traced after the pen tip part 7 is not in contact with the writing surface. Judgment is due to impact. As described above, when the state detection unit 49 makes contact with the pen tip 7 and the writing surface based on the detection result of the contact detection unit 47 and the detection result of the friction detection unit 48, and when the pen tip 7 leaves the writing surface. Can be accurately recognized, such as when the pen tip 7 comes into contact with the writing surface and when the pen tip 7 touches the writing surface. Noise generated when moving away from the surface can be removed from the acceleration signal. For example, in the figure, since the acceleration of the L-shaped writing start portion A and the writing end portion C is due to noise, the acceleration writing start portion A stored in the storage unit is set to zero, and after the writing end portion C and thereafter. Correct acceleration to zero.
[0023]
The writing operation unit 43 recognizes input characters and the like based on the low frequency components of the signals from the acceleration sensors 2a, 2b, and 2c extracted by the LPF 46 and the detection result of the state detection unit 49. Here, recognition of an input character etc. is performed by extracting the characteristic, for example, combining wavelet transformation and neural network operation.
[0024]
The storage unit 5 stores the calculation result of the calculation unit 4 and the like. The communication unit 6 transmits the calculation result of the calculation unit 4 stored in the storage unit 5 to the host device (not shown).
[0025]
Here, in the above embodiment, whether or not the pen tip portion 7 and the writing surface are in contact with each other is detected based on a signal from the pressure sensitive sheet 3, but without using the pressure sensitive sheet 3, for example in FIG. As shown, the writing state of the pen tip 7 may be detected based on signals from the acceleration sensors 2a, 2b, 2c. As already described, the calculation unit 4 includes the input processing unit 41, the contact state determination unit 42, and the writing calculation unit 43. The input processing unit 41 includes, for example, an AD converter 44, an HPF 45, and an LPF 46. The AD converter 44 digitally converts signals from the acceleration sensors 2a, 2b, and 2c. The HPF 45 extracts a high frequency component from the signal digitally converted by the AD converter 44 as already described. The LPF 46 extracts a low frequency component from the signal digitally converted by the AD converter 44. This is because the acceleration component due to the movement of the pen tip portion 7 appears in the low-frequency part of the signals from the acceleration sensors 2a, 2b, 2c.
[0026]
The contact state determination unit 42 includes a stationary detection unit 50, a friction detection unit 48, and a state detection unit 49. The stationary detection unit 50 detects whether or not the pen tip unit 7 is stationary by differentiating the low frequency portion of the acceleration signal extracted by the LPF 46 and comparing the differentiated value with a predetermined threshold value, for example. This is because the acceleration detected using the acceleration sensors 2a, 2b, and 2c is a constant value when the pen tip 7 is stationary. Here, instead of differentiating the acceleration signal and comparing it with a predetermined threshold, the stillness detection unit 50 compares the acceleration signal with a predetermined threshold or compares the difference value of the acceleration signal with a predetermined threshold. Anyway.
[0027]
Based on the detection result of the friction detection unit 48 and the detection result of the stationary detection unit 50, the state detection unit 49 is in a state where the pen tip portion 7 and the writing surface are not rubbed and are not moving. To detect. Here, the state in which the pen tip portion 7 and the writing surface are not rubbed and not moving means that the pen tip portion 7 is stationary in the air or the pen tip portion 7 is in contact with the writing surface. It is in contact but is stationary. This is a state of not writing or a state where the pen tip portion 7 is approaching the corner portion of the input figure. Thus, by using the signals from the acceleration sensors 2a, 2b, and 2c, the writing state of the pen tip portion 7 can be detected with a simple configuration as compared with the case where the pressure sensor 3 is used.
[0030]
As shown in FIG. 2, the state detection unit 49 writes when the pen tip 7 and the writing surface come into contact with each other based on the detection result of the contact detection unit 47 and the detection result of the friction detection unit 48. Instead of detecting when leaving the surface, as shown in FIG. 6 , the state detection unit 49 includes a friction time measuring unit 51 that measures the duration of the state in which the pen tip portion 7 and the writing surface are in friction. The duration time measured by the friction time measuring unit 51 may be compared with a predetermined threshold value to detect when the pen tip portion 7 and the writing surface are in contact with each other and when the pen tip portion 7 is separated from the writing surface. . For example, when the duration time measured by the friction time measuring unit 51 is less than a predetermined threshold, the state detecting unit 49 is in contact with the pen tip 7 and the writing surface or when the pen tip 7 is separated from the writing surface. If the duration time measured by the friction time measuring unit 51 is equal to or greater than a predetermined threshold, it is determined that writing is being input. Accordingly, when the state detection unit 49 makes contact with the pen tip 7 and the writing surface based on the detection result of the contact detection unit 47 and the detection result of the friction detection unit 48, and when the pen tip 7 leaves the writing surface. It is possible to maintain substantially the same effect as in the case of detection and to simplify the configuration. The writing calculation unit 43 corrects the acceleration stored in the storage unit 5 so that the acceleration when the pen tip portion 7 and the writing surface come into contact with each other and when the pen tip portion 7 leaves the writing surface becomes zero. After that, it recognizes characters and detects the locus of the pen tip.
[0031]
In the above embodiment, the friction detection unit 48 detects whether or not the pen tip 7 and the writing surface are rubbed based on the acceleration signals from the acceleration sensors 2a, 2b, and 2c. Even if it detects whether the nib part 7 and the writing surface are rubbing by attaching the microphone etc. to 7 and detecting the sound generated when the nib part 7 and the writing surface are rubbed good.
[0032]
In the above embodiment, the three acceleration sensors 2a, 2b, and 2c are used to detect the acceleration in the Xs axis direction, the acceleration in the Ys axis direction, and the acceleration in the Zs axis direction. Further, the acceleration in the Ys axis direction may be detected. Further, when the gyros 9a and 9b are used, an acceleration sensor may not be provided, and characters and the like input may be recognized based on characteristics of changes in signals from the gyros 9a and 9b.
[0033]
In the above embodiment, the writing unit 43 is provided in the calculating unit 4 and the pen-type input device 1 recognizes characters and the like. However, the writing unit 43 is provided in the host device, The input device 1 may transmit the determination result of the contact state determination unit 42 and the physical quantity detected using the acceleration sensors 2a, 2b, 2c, and the like to the host device.
[0034]
Further, since it is determined whether or not the pen tip portion 7 and the writing surface are in contact with each other, a micro switch or the like may be used instead of using the pressure sensitive sheet 3.
[0035]
【The invention's effect】
As described above, the present invention detects whether the pen tip portion and the writing surface are in contact with each other and whether the pen tip portion and the writing surface are rubbed, and based on the detection result, the pen tip portion. And the writing surface are in contact with each other and when the pen tip portion is separated from the writing surface, the written state is recognized using the detection result, so the pen tip portion and the writing surface The noise which occurs when the pen tip part and the writing surface are separated can be detected and removed.
[0036]
In addition, it detects whether or not the nib portion and the writing surface are rubbing, measures the duration of the friction state between the nib portion and the writing surface, and the nib portion writes the writing surface based on the measured duration. The noise generated when touching and separating from the pen can be removed, and the noise generated when the pen tip and the writing surface come into contact with each other and when the pen tip and the writing surface leave can be removed and the configuration can be simplified. can do.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a pen-type input device.
FIG. 2 is a configuration diagram of a calculation unit.
FIG. 3 is an explanatory diagram when an L-shape is drawn.
FIG. 4 is a waveform diagram of outputs of an acceleration sensor and a pressure sensitive sheet.
FIG. 5 is a configuration diagram of a calculation unit using an acceleration sensor instead of a pressure-sensitive sheet.
FIG. 6 is a configuration diagram of a calculation unit having a friction time measuring unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1; Pen type input part, 2; Acceleration sensor, 3; Pressure sensitive sheet, 4; Calculation part 41; Input process part, 42; Contact state judgment part, 43;
47; contact detection unit, 48; friction detection unit, 49; state detection unit, 50; stationary detection unit,
51; Friction time measuring part, 7; Pen tip part, 8; Pen shaft, 9;

Claims (2)

In a pen-type input device for writing input,
  Having a pressure-sensitive sensor, an acceleration sensor, and an arithmetic unit;
  The pressure sensor detects the pressure from the writing surface applied to the pen tip, the acceleration sensor detects the acceleration of the pen axis coordinate system,
  The calculation unit has a contact detection unit, a friction detection unit, a state detection unit, and a writing calculation unit,
  The contact detection unit compares the pressure signal output from the pressure sensor with a predetermined threshold value to determine whether the pen tip and the writing surface are in a non-contact state or a contact state,
  The friction detection unit compares the high frequency component of the acceleration signal output from the acceleration sensor with a predetermined threshold value to determine whether the pen tip and the writing surface are rubbing,
  The state detection unit is output from the acceleration sensor until the friction detection unit detects the first friction-free state between the pen tip and the writing surface after the contact detection unit determines that the pen tip has contacted the writing surface. The acceleration signal is output from the acceleration sensor until the last friction-free state between the nib and the writing surface is detected by the friction detection unit after the nib is not in contact with the writing surface. The acceleration signal is judged as noise,
  The pen-type input device, wherein the writing operation unit recognizes an input character or the like based on a low-frequency component of a signal obtained by removing a portion determined as noise by the state detection unit from the acceleration signal output from the acceleration sensor. In a pen-type input device for writing input,
  It has an acceleration sensor and a calculation unit,
  The acceleration sensor detects the acceleration of the pen axis coordinate system,
  The calculation unit has a friction detection unit, a friction time measuring unit, a state detection unit and a writing calculation unit,
  The friction detection unit compares the high frequency component of the acceleration signal output from the acceleration sensor with a predetermined threshold value to determine whether the pen tip and the writing surface are rubbing,
  The friction time measuring unit measures the duration of the state where the friction detection unit determines that the pen tip and the writing surface are rubbing,
  The state detection unit determines whether the acceleration signal output from the acceleration sensor is noise by comparing the friction duration measured by the friction time measuring unit with a predetermined threshold value,
  The pen-type input device, wherein the writing operation unit recognizes an input character or the like based on a low-frequency component of a signal obtained by removing a portion determined as noise by the state detection unit from the acceleration signal output from the acceleration sensor.

Images