JP2731180B2 - Handwriting verification device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a handwriting verification device that verifies input handwriting of a signature character with handwriting of a previously registered signature character.

(Prior Art) In a conventional handwriting verification apparatus of this type, a signature character written on an input sheet is optically read, and a signature character registered in advance and a shape are compared.

(Problems to be Solved by the Invention) However, when signing an input form, it is possible to write the character in a shape resembling the handwriting of another person. A conventional handwriting verification device that performs shape verification with a given signature character has not yet been put to practical use as a means for confirming the identity of the user.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned problems and to provide a handwriting verification device which can be used as a means for confirming the identity of a person.

(Means for Solving the Problem) In the present invention, in order to solve the problem, the invention is described in claim (1).
A coordinate input device having means for detecting a coordinate value of a position designated on the coordinate input surface by the position indicator and a pen pressure on the coordinate input surface by the position indicator; Sampling means for sampling the coordinate values and the writing pressure at predetermined time intervals and outputting as handwriting data composed of a plurality of sampling data;
Based on the handwriting data, a central coordinate calculating means for calculating the coordinates of the central point of the character string input using the position indicator, and each of the sampling data from the central coordinates calculated by the central coordinate calculating means A distance calculating means for calculating a distance to the coordinates, an average distance calculating means for calculating an average value of a plurality of distances calculated by the distance calculating means, and a distance average value calculated by the average distance calculating means. A standardization information calculation unit that calculates standardization information obtained by standardizing each of the plurality of distances calculated by the distance calculation unit; and a pen pressure and a sampling pressure corresponding to each of the sampling data. Standardized handwriting information consisting of the standardized information obtained by
Handwriting matching means for comparing with handwritten handwriting information which is compared with pre-registered standardized handwriting information to judge whether or not the handwriting of the character string input using the position indicator is the handwriting of a pre-registered person; The device was configured.

According to a second aspect of the present invention, the coordinate input device in the handwriting verification device according to the first aspect includes a loop coil group in the X direction in which a large number of loop coils are arranged in the X direction and a large number of loop coils. A tablet comprising a group of Y-direction loop coils arranged side by side in the Y-direction, and a position indicator having a tuning circuit including at least a coil and a capacitor, wherein a tuning frequency changes around a predetermined frequency in accordance with writing pressure; X direction selecting means for sequentially selecting one loop coil from the X direction loop coil group of the tablet, and Y direction selecting means for sequentially selecting one loop coil from the Y direction loop coil group of the tablet. Signal generating means for generating the AC signal of the predetermined frequency; signal detecting means for detecting the AC signal of the predetermined frequency; X direction and Y selected by the
Connection switching means for sequentially connecting the signal generating means and the signal detecting means alternately to each loop coil in the direction;
And a coordinate detecting means for obtaining input coordinates in the X direction and the Y direction by the position indicator based on an AC signal detected by the signal detecting means from each of the loop coils in the direction and the Y direction.

According to a third aspect of the present invention, in the handwriting verification device according to the second aspect, the position indication is performed based on an AC signal detected by the signal detection means from one of the loop coils in the X direction or the Y direction. A change in the tuning frequency in the tuning circuit of the device was detected as a change in the phase with respect to the predetermined frequency, and the change in the phase was used as a physical quantity.

(Operation) According to claim (1), the coordinate input device detects the coordinate value of the position input by the position indicator and the pen pressure on the coordinate input surface by the position indicator. The detected coordinate values and pen pressure are sampled at predetermined time intervals by the sampling means and output as handwriting data composed of a plurality of sampling data. In addition, the center coordinate calculation unit calculates the coordinates of the center point of the character string input using the position indicator based on the handwriting data, and calculates the coordinates of the center point calculated by the center coordinate calculation unit. The distance to each coordinate of each sampling data is calculated by the distance calculating means, and the average value of the plurality of distances calculated by the distance calculating means is calculated by the average distance calculating means. further,
The normalization information calculating means calculates, using the distance average value calculated by the average distance calculating means, standardized information obtained by normalizing each of the plurality of distances calculated by the distance calculating means. As a result, coordinate information that can be compared for handwriting comparison regardless of the size of the character is obtained.
Further, the standardized handwriting information including the writing pressure represented by each of the sampling data and the standardized information obtained in correspondence with each of the sampling data is registered by the handwriting determining unit, and the standardized handwriting information registered in advance is used. Then, it is determined whether or not the handwriting of the character string input using the position indicator is the handwriting of the registered person in advance.

According to claim (2), the signal generating means is connected to one of the loop coils selected by the selecting means in the X direction from the group of loop coils in the X direction of the tablet via the connection switching means, and the AC of a predetermined frequency is supplied. When the signal is applied, a radio wave is generated from the one loop coil, and the radio wave excites a coil of a tuning circuit of the position indicator on the tablet, causing the tuning circuit to generate an induced voltage having the predetermined frequency.

Thereafter, when the signal generation means is disconnected from the one loop coil by the connection switching means and the signal detection means is connected instead, the radio wave is no longer generated from the one loop coil, but instead the radio wave is transmitted to the tuning circuit. A radio wave is generated from the coil of the tuning circuit based on the generated induced voltage, and the radio wave excites the one loop coil in reverse to generate an AC signal, that is, an induced voltage.

The transmission and reception of the radio waves are performed for all the loop coils in the X direction and the Y direction by the selection means and the connection switching means in the X and Y directions, and the induced voltages corresponding to the respective loop coils are detected by the signal detection means. Since the voltage value of the induced voltage depends on the distance between each loop coil and the coil of the tuning circuit, that is, the position indicator, the coordinate detector detects the voltage value in the X direction and the Y direction by the position indicator based on these values. Input coordinates are calculated.

According to claim (3), the change of the tuning frequency in the tuning circuit of the position indicator is determined based on the AC signal detected by the signal detecting means from one of the loop coils in the X direction or the Y direction. The change is detected as a phase change with respect to the predetermined frequency, and the pen pressure is detected based on the change in the phase.

(Embodiment) FIG. 1 shows an embodiment of the handwriting collation apparatus of the present invention, in which 10 is a tablet, 20 is a position indicator, 30 is a control circuit, 31 is a signal generation means (circuit), 32 and 33 are selection means (circuits) in the X and Y directions. Reference numerals 34 and 35 denote transmission / reception switching circuits, reference numeral 36 denotes an XY switching circuit, and reference numeral 37 denotes a reception timing switching circuit, which constitute connection switching means. Also,
38 is a bandpass filter (BPF), which constitutes a signal detecting means. 39 is a detector, 40 is a low-pass filter (LP
F), and these constitute the coordinate detecting means including the processing in the control circuit 30 described later. Also, 41 and 42 are phase detectors (PSD), 43 and 44 are low-pass filters (LPF),
These constitute phase detection means including the processing in the control circuit 30 described later. Reference numerals 45 and 46 denote drive circuits, 47 and 48 denote amplifiers, 49 denotes a host computer, 50 denotes a main storage device, 51 denotes a memory required for calculation, and 52 denotes a display device. The handwriting determination means includes a host computer 49, a main storage device 50, and a calculation memory 51.

FIG. 2 shows details of the loop coil group 11 in the X direction and the loop coil group 12 in the Y direction that constitute the tablet 10. A large number of X-direction loop coil groups 11 are arranged in parallel with each other along the X-direction, for example,
It consists of 48 loop coils 11-1, 11-2, ... 11-48,
A large number of loop coils 12 arranged in the Y direction are arranged in parallel with each other and overlap with each other along the Y direction.
, 12-48, the X-direction loop coil group 11 and the Y-direction loop coil group 12
Are closely overlapped with each other (however, they are illustrated separately for easy understanding in the drawings), and further housed in a case (not shown) made of a nonmetallic material. Here, each loop coil is configured by one turn,
Multiple turns may be provided as needed.

FIG. 3 shows a specific structure of the position indicator 20.
A pen shaft 21 made of a non-metallic material such as a synthetic resin, a core 23 having a ferrite chip 22, a coil 24 capable of slidably housing the core 23 therein, and a rear end of the core 23 It comprises a core holder 25 for holding, a spring 26 for supporting the core holder 25 so as to be slightly displaceable with respect to the pen shaft 21, and a capacitor 27. The core body 23 has ink built-in like the core of a ballpoint pen, and can draw characters on paper.

As shown in FIG. 1, the coil 24 and the capacitor 27 are connected in series with each other to constitute a well-known tuning circuit 28. The inductance of the coil 24 and the capacitance value of the capacitor 27 are adjusted by the tuning ( (Resonance) frequency is set to a value that is substantially equal to a predetermined frequency f0. Here, the core 23
The ferrite chip 22 is positioned at the end of the coil 24 in a state in which is held by the core holder 25, and when the entry sheet fixed on the tablet 10 is signed using the position indicator 20, the brush at that time is written. The core 23, that is, the ferrite chip 22, moves in response to the pressure, whereby the inductance of the coil 24 changes, and the tuning frequency in the tuning circuit 28 described above slightly changes.

Next, the operation of the device will be described together with its configuration.
First, the manner in which radio waves are transmitted and received between the tablet 10 and the pen 20 and the signals obtained at this time will be described with reference to FIG.

The control circuit 30 includes a well-known microprocessor or the like, controls the signal generation circuit 31, and controls switching of each loop coil of the tablet 10 via the selection circuits 32 and 33 according to the flowchart shown in FIG. Also,
The switching of the coordinate detection direction is controlled for the XY switching circuit 36 and the reception timing circuit 37, and the low-pass filters 40 and 4 are further controlled.
The output values from 3,44 are converted from analog to digital (A / D), and the arithmetic processing described later is executed to obtain the input coordinates by the position indicator 20, and the phase of the received signal is detected. Send to 49.

The selection circuit 32 sequentially selects one loop coil from the X-direction loop coil group 11, and the selection circuit 33 sequentially selects one loop coil from the Y-direction loop coil group 12. And operate according to the information from the control circuit 30.

The transmission / reception switching circuit 34 alternately connects the selected one loop coil in the X direction to the drive circuit 45 and the amplifier 47, and the transmission / reception switching circuit 35 connects the one loop coil in the selected Y direction. Are alternately connected to the drive circuit 46 and the amplifier 48, which operate according to a transmission / reception switching signal described later.

The signal generation circuit 31 has a predetermined frequency f0, for example, a rectangular wave signal A having a frequency of 500 kHz, a signal B obtained by delaying the phase of the rectangular wave signal A by 90 °, a transmission / reception switching signal C having a predetermined frequency fK, for example, 15.625 kHz, and a reception timing signal. D is generated. The rectangular wave signal A is sent to the phase detector 41 as it is, and is converted into a sine wave signal E by a low-pass filter (not shown).
Further, the rectangular wave signal B is transmitted to one of the driving circuits 45 and 46 via the XY switching circuit 36, and the rectangular wave signal B is transmitted to the phase detector 42.
The transmission / reception switching signal C is transmitted to transmission / reception switching circuits 34 and 35, and the reception timing signal D is transmitted to the reception timing switching circuit 37.

Now, assuming that information for selecting the X direction is input from the control circuit 30 to the XY switching circuit 36 and the reception timing switching circuit 37, the sine wave signal E is sent to the driving circuit 45 and converted into a balanced signal. The signal is transmitted to the transmission / reception switching circuit 34.The transmission / reception switching circuit 34 outputs the signal to the selection circuit 32 from the transmission / reception switching circuit 34 in order to switch and connect one of the driving circuit 45 and the amplifier 47 based on the transmission / reception switching signal C. The signal F is a signal F that outputs or does not output a 500 kHz signal every time T (= 1 / 2fk), in this case, every 32 μsec.

The signal F is transmitted to one of the loop coils 11-i (i = 1, 2,..., 48) in the X direction of the tablet 10 via the selection circuit 32. Generates radio waves based on

At this time, when the position indicator 20 is held in a substantially upright state, that is, in a used state on the tablet 10, the radio wave excites the coil 24 of the position indicator 20, and the tuning circuit 28 transmits the signal F to the tuning circuit 28. A synchronized induced voltage G is generated.

Thereafter, when the signal F enters a period in which there is no signal, that is, a reception period, and the loop coil 11-i is switched to the amplifier 47 side, the radio wave from the loop coil 11-i immediately disappears, but the induced voltage G is reduced. It gradually attenuates according to the loss in the tuning circuit 28.

On the other hand, the current flowing through the tuning circuit 28 based on the induction voltage G causes the coil 24 to emit radio waves. The radio wave is an amplifier
In order to excite the loop coil 11-i connected to 47 in reverse, an induced voltage is generated in the loop coil 11-i by radio waves from the coil 24. The induced voltage is sent from the transmission / reception switching circuit 34 to the amplifier 47 and amplified to the reception signal H only during the reception period, and is further transmitted to the reception timing switching circuit 37.

In the reception timing switching circuit 37, either one of the selection information in the X direction or the Y direction, here, the selection information in the X direction,
A reception timing signal D, which is substantially an inverted signal of the transmission / reception switching signal C, is input. The reception signal H is output when the signal D is at a high (H) level, and the reception signal H is output during a low (L) level. Since nothing is output, a signal I (substantially the same as the reception signal H) is obtained at the output.

The signal I is transmitted to a band filter 38. The band filter 38 is a ceramic filter having a frequency f0 as a unique frequency, and a signal J having an amplitude corresponding to the energy of the frequency f0 component in the signal I. (Strictly, in a state where several signals I are input to the bandpass filter 38 and converged) are transmitted to the detector 39 and the phase detectors 41 and 42.

The signal J input to the detector 39 is detected and rectified,
Low-pass filter with sufficiently low cutoff frequency after signal K
At 40, a voltage value corresponding to almost half of the amplitude, for example, Vx
And transmitted to the control circuit 30.

The voltage value Vx of the signal L is determined by the position indicator 20 and the loop coil.
A value dependent on the distance between the loop coils 11-i, here a value substantially inversely proportional to the fourth power of the distance, and changes when the loop coils 11-i are switched. By converting the obtained voltage value Vx into a digital value and performing an arithmetic process described later on these,
Input coordinates in the X direction by the position indicator 20 are obtained. Note that the input coordinates in the Y direction by the position indicator 20 are obtained in the same manner.

On the other hand, the rectangular wave signals A and B are input to the phase detectors 41 and 42 as detection signals. At this time, if the phase of the signal J substantially matches the phase of the rectangular wave signal A, the phase The detector 41 outputs a signal M1 (substantially the same as the signal K) obtained by inverting the signal J to the positive side, and the phase detector 42 outputs a signal M2 having a symmetrical waveform on the positive side and the negative side. I do.

The signal M1 is converted to a DC signal N1 (substantially the same as the signal L) having a voltage value corresponding to almost half the amplitude of the signal J, that is, Vx by the low-pass filter 43 similar to the above, and the control circuit 30
The signal M2 is converted to a DC signal N2 by a similar low-pass filter 44 and sent to the control circuit 30, where the positive and negative components of the signal M2 of the phase detector 42 are Since they are the same, the voltage value of the output of the low-pass filter 44 is 0
[V].

The control circuit 30 converts the output values of the low-pass filters 43 and 44, here the signals N1 and N2, into digital values, and further uses the digital values to perform the arithmetic processing of the following equation (1). The phase difference θ between the signal added to the signal 42, here, J and the rectangular wave signal A is obtained.

θ = −tan ⁻¹ (VQ / VP) (1) where VP indicates a digital value corresponding to the output of the low-pass filter 43 and VQ indicates a digital value corresponding to the output of the low-pass filter 44 . For example, in the case of the signal J described above, the voltage value of the signal N1 is Vx, but the voltage value of the signal N2 is 0.
[V], that is, VQ = 0, so that the phase difference θ = 0 °.

By the way, the phase of the signal J changes according to the tuning frequency in the tuning circuit 28 of the position indicator 20. That is, when the tuning frequency in the tuning circuit 28 matches the predetermined frequency f0, an induced voltage having the frequency f0 is generated in the tuning circuit 28 during both the signal transmission period and the signal reception period, and the induced current is synchronized with this. Flows, the received signal H (or I)
And the phase of the signal J also coincides with the rectangular signal A.

On the other hand, the tuning frequency in the tuning circuit 28 is a predetermined frequency.
In the case where the frequency does not coincide with f0, for example, a frequency slightly lower than the frequency f0, for example, f1, an induced voltage having a frequency f0 is generated in the tuning circuit 28 during a signal transmission period. Induction current with phase lag flows,
In addition, during the signal receiving period, an induced voltage having a frequency f1 and an induced current synchronized therewith flow, so that the frequency of the received signal H (or I) is slightly lower than the frequency of the rectangular wave signal A. The phase is also slightly delayed. As described above, since the bandpass filter 38 uses only the frequency f0 as the frequency, the frequency shift of the input signal to the lower side is output as a phase delay,
Therefore, the phase of the signal J is further delayed than the received signal H (or I).

Conversely, when the tuning frequency in the tuning circuit 28 is a frequency slightly higher than the predetermined frequency f0, for example, f2, an induced voltage having a frequency f0 is generated in the tuning circuit 28 during a signal transmission period. An induced current with a phase advance flows through the tuning circuit 28, and an induced voltage having substantially the frequency f2 and an induced current synchronized therewith flow during the signal receiving period. Therefore, the frequency of the received signal H (or I) is The frequency is slightly higher than the frequency of the rectangular wave signal A, and its phase is slightly advanced. In the band-pass filter 38, the shift of the frequency of the input signal to the higher side will be output as the phase advance contrary to the case described above.
The phase of the signal J is further advanced than the reception signal H (or I).

As described above, the tuning frequency of the tuning circuit 28 is determined by the position indicator.
Since the phase difference θ changes according to the pen pressure applied to 20, the phase difference θ obtained by the above equation (1) also changes according to the pen pressure.
In the present embodiment, the phase difference θ is set in advance to about −60 ° when no writing pressure is applied to the position indicator 20 and to about 60 ° when writing pressure is applied most.

The obtained phase difference θ is, for example, added by 40 ° so that the tip of the core body 23 of the position indicator 20 is slightly contacted with the surface of the tablet 10 by 40 °, and is in a range of −20 ° to 100 °. Is transmitted to the host computer 49 together with the coordinate values in the X-direction and the Y-direction at predetermined time intervals (the above-mentioned addition of 40 ° is also performed on the host computer 49 side). good.).

Next, referring to FIGS. 5 to 9, a description will be given in detail of collation of handwriting along with the coordinate detection operation and the phase detection operation.

First, when the power of the entire apparatus is turned on and the measurement is started, the control circuit 30 transmits information for selecting the X direction to the XY switching circuit.
36 and the reception timing switching circuit 37,
Among the loop coils 11-1 to 11-48 in the X direction of the tablet 10, information for selecting the first loop coil 11-1 is transmitted to the selection circuit 32, and the transmission / reception switching circuit 34 transmits the loop coil 11-1.
Connect to

The transmission / reception switching circuit 34 alternately connects the loop coil 11-1 to the driving circuit 45 and the amplifier 47 based on the transmission / reception switching signal C described above. At this time, the driving circuit 45 operates during the transmission period of 32 μsec in FIG. 500kHz 16 as shown in (a)
Are sent to the loop coil 11-1 (note that
FIG. 4 shows only five of them for convenience of the drawing. ).

The switching between transmission and reception is repeated seven times for one loop coil, here 11-1, as shown in FIG. 6 (b). The seven transmission and reception repetition periods correspond to one loop coil selection period (448 μsec).

At this time, an induced voltage is obtained from the output of the amplifier 47 every seven reception periods for one loop coil, and this induced voltage is applied to the bandpass filter 38 via the reception timing switching circuit 37 as described above. The signal is transmitted, averaged, and transmitted to the control circuit 30 via the detector 39, the phase detectors 41 and 42, and the low-pass filters 40, 43 and 44.

The control circuit 30 performs A / D conversion of the output value of the low-pass filter 40 and inputs it, and temporarily stores the detection value as a detection voltage depending on the distance between the position indicator 20 and the loop coil 11-1, for example, Vx1.

Next, the control circuit 30 sends information for selecting the loop coil 11-2 to the selection circuit 32, connects the loop coil 11-2 to the transmission / reception switching circuit 34, and sets the position indicator 20 and the loop coil 11-2.
Obtain the detection voltage Vx2 proportional to the distance to and memorize it,
Thereafter, similarly, the loop coils 11-3 to 11-48 are sequentially connected to the transmission / reception switching circuit 34, and the distance between the loop pointer and the position indicator 20 in the X direction as shown in FIG. The proportional detection voltages Vx1 to Vx48 (however, only a part thereof is shown in an analog expression in FIG. 6C) are stored.

The actual detected voltage is, as shown in FIG.
Can be obtained only for a few loop coils before and after the position (xp) where is placed.

The control circuit 30 checks whether or not the voltage value of the stored detection voltage is equal to or higher than a certain detection level. If the voltage value is equal to or lower than the certain detection level, the control circuit 30 again selects each loop coil in the X direction and detects the voltage. Repeat, if it is above a certain detection level, proceed to the next process.

Next, the control circuit 30 sends selection information in the Y direction to the XY switching circuit 36 and the reception timing switching circuit 37, switches the selection circuit 33 and the transmission / reception switching circuit 35 in the same manner as described above, A position indicator 20 obtained by A / D converting the output value of the filter 40 and each of the Y-direction loop coils 12-1 to 12-12
The detection voltage depending on the distance from -48 is temporarily stored. Thereafter, a level check is performed in the same manner as described above. If the level is below a certain detection level, the process returns to the selection of each loop coil in the X direction and voltage detection again. As will be described later, the coordinate values of the position indicator 20 in the X and Y directions are calculated from the values.

Next, the control circuit 30 controls the loop coil 11-1 in the X direction.
~ 11-48 (or Y-direction loop coils 12-1 to 12-48)
The information for selecting the loop coil (peak coil) for which the maximum detection voltage is obtained is transmitted to the selection circuit 32 (or 33), and the transmission and reception of the radio wave is repeated a plurality of times, for example, seven times. The output values obtained by the bandpass filters 43 and 44 are A / D converted, and the phase difference θ is calculated as described above.

The phase difference θ is added by 40 °, converted into phase information, transferred to the host computer 49 at predetermined time intervals together with the coordinate values of the position indicator 20 in the X and Y directions, and stored in the arithmetic memory 51. Is done.

When the first coordinate detection operation and the phase detection operation are completed in this way, the control circuit 30 performs the second and subsequent coordinate detection operations as shown in FIG. Of the loop coils 11-48, the information for selecting only a certain number of loop coils around the loop coil at which the maximum detection voltage is obtained, for example, only 10 loop coils, is selected by the selection circuit 32.
And the Y-direction loop coils 12-1 to 12-48
Out of the loop coil at which the maximum detection voltage is obtained, a fixed number of values before and after that, and information for selecting only the ten loop coils are sent to the selection circuit 33, and the output value is obtained in the same manner as described above. Then, an X-direction and Y-direction coordinate detection operation and a phase detection operation for the position indicator 20 are performed, and the obtained coordinate values and phase information are transferred to the host computer 49, and thereafter, these operations are repeated.

In addition, if the level check described above is explained in detail,
Check whether the maximum value of the detection voltage has reached the detection level and which loop coil has the maximum value of the detection voltage, and if the detection level has not been reached, stop the subsequent coordinate calculation and the like. This is a process of setting the center of the loop coil to be selected in the next coordinate detection operation and phase detection operation.

X-direction or Y-direction coordinate values, for example, as one method of calculating the coordinate value xp, approximate the waveform near the maximum value of the detection voltage Vx1 ~ Vx48 with a suitable function, the coordinates of the maximum value of the function There is a way to ask.

For example, in FIG. 6 (c), the maximum detection voltage Vx3
, And the detection voltages Vx2 and Vx4 on both sides thereof can be calculated as follows by approximation by a quadratic function (however, the coordinate values of the center positions of the loop coils 11-1 to 11-48 are x1 to
x48, and the interval is Δx. ). First, from the respective voltages and coordinate values, Vx2 = a (x2-xp) ² + b (2) Vx3 = a (x3-xp) ² + b (3) Vx4 = a (x4-xp) ² + b ... (4) where a and b are constants (a <0). X3−x2 = Δx (5) x4−x2 = 2Δx (6) By substituting the equations (5) and (6) into the equations (3) and (4) and rearranging, xp = x2 + Δx / 2 ｛(3Vx2-4Vx3 + Vx4) / (Vx2-2−Vx3 + Vx4)｝ (7) .

Therefore, the maximum value of the detection voltage obtained at the time of the level check and the detection voltages before and after that are extracted from each of the detection voltages Vx1 to Vx48, and these and the one of the loop coil from which the maximum value of the detection voltage is obtained are extracted. The coordinate value xp of the position indicator 20 can be calculated by performing an operation corresponding to the above equation (7) from the coordinate value (known) of the previous loop coil.

On the other hand, the host computer 49 stores the data transferred from the control circuit 30 in the arithmetic memory 51, and stores the data in the main storage device.
Compare with the registration data stored in 50.

Next, the operation when registering handwriting data will be described with reference to the flowchart shown in FIG.

Now, a case will be described as an example in which the signature of "Patent Taro" shown in FIG. 10 is registered and collated.

The host computer 49 stores the above-described data transferred from the control circuit 30 in the arithmetic memory 51 (S
1) (S2), it is determined whether or not the signature is completed (S3).
In this embodiment, information indicating the end of the signature is input by a switch provided in the host computer 49. As a result of this judgment,
If the signature has not been completed, the process proceeds to S1. If the signature has been completed, the first and last names are recognized as character patterns from the data stored in the operation memory 51 (S4). Next, as shown in FIG. 11, n pieces of data D1 to Dn are sampled at equal time intervals from the data between the data of the signature start point A and the data of the signature end point B shown in FIG. 10 (S5). . Using the sampling data D1 to Dn, the width X1 in the X direction and the width Y1 in the Y direction shown in FIG. 10 are calculated (S6) (S7). Next, the coordinates of the central point P of the signature are calculated (S8), and the distance 11 between the coordinates of the point P and the respective coordinates of the sampling data D1 to Dn is calculated.
11n is calculated (S9). Further, an average value of the distances 11 to 1n is calculated (S10), and values L1 to Ln obtained by normalizing the distances 11 to 1n are calculated with the average value (S11). As a result, as shown in FIG. 12, the movement of the tip of the core
The distance from the point P in FIG. 10 can be obtained as a normalized value. Next, the sampling data D1 to Dn and the standardization information
L1 to Ln are stored as handwriting data in the main storage device 50 together with the first and last names recognized in the character pattern (S12). By the above operation, the handwriting data of the signature by the person is registered.

Next, the operation for collating the signature handwriting will be described with reference to the flowchart shown in FIG.

The host computer 49 stores the data transferred from the control circuit 30 in the arithmetic memory 51 (SP1) (SP
2), it is determined whether or not the signature has been completed (SP3). In this embodiment, information indicating the end of the signature is input by a switch provided in the host computer 49. If the result of this determination is that the signature has not been completed, the process proceeds to SP1. If the signature has been completed, the first and last names are recognized as character patterns from the data stored in the operation memory 51 (SP4). Next, the first and last names registered in the main storage device 50 are searched (SP5), and it is determined whether or not the first and last names corresponding to the input first and last names are registered (SP6). If the result of this determination is that the input first and last names are not registered, the fact that they have not been registered is displayed on the display device 52 (SP7). As a result of the determination of SP6, when the first and last names corresponding to the input first and last names are registered, using the input data stored in the arithmetic memory 51, the data of the signature start point Ac and the data of the signature end point Bc are used. The data n of data Dcl to Dcn are sampled at equal time intervals from the data between (SP8).
Using the sampling data Dcl to Dcn, a width Xcl in the X direction and a width Ycl in the Y direction of the input signature are calculated (SP9).
(SP10). Next, the coordinates of the central point Pc of the signature are calculated (SP1
1) The distances 1cl to 1cn between the coordinates of the point Pc and the respective coordinates of the sampling data Dcl to Dcn are calculated (SP12).
Further, an average value of these distances 1cl to 1cn is calculated (SP1
3) The values Lcl to Lc that standardize distances 1cl to 1cn with this average value
Calculate n (SP14). Next, the phase information θcl to θcn of the input data Dcl to Dcn and the standardized information Lcl to Lcn are compared with the registered handwriting data in correspondence with the phase information θ1 to θn and the standardized information L1 to Ln (SP15). ). The comparison method at this time is, for example, to obtain a difference for each of the registered handwriting data and the n values of the handwriting data phase information and the standardization information based on the input data, and further, the absolute value of the difference is calculated. The average value is calculated, and it is assumed that the average value matches when the average value is smaller than the reference value. Next, based on the result of the comparison in SP14, it is determined whether the handwriting matches (SP1).
6) If they do not match, display that the handwriting does not match is displayed on the display device 52 (SP17), and if they match, display that the handwriting matches on the display device 52.

Note that the number of loop coils and the arrangement thereof in the embodiment are merely examples, and it is needless to say that the present invention is not limited to this.

In the present embodiment, the inductance of the coil 24 is changed. However, the same effect can be obtained by changing the capacitance of the capacitor 27.

Further, in the present embodiment, the signature is fixed on the tablet 10 with the entry form fixed.
May be provided, and the signed character may be displayed on the display device 52.

Further, the comparison method using the pen pressure in the embodiment is also an example, and it is needless to say that the present invention is not limited to this.

Furthermore, in the present embodiment, the pen pressure is detected as a change in the tuning frequency of the tuning circuit of the position indicator as a change in the phase with respect to a predetermined frequency.However, the present invention is not limited to this. The same effect can be obtained by detecting a physical quantity such as luminance of light, voltage, current, magnetic flux density, frequency of ultrasonic waves, and the like.

(Effect of the Invention) As described above, according to the first aspect, the coordinate value of the position input by the position indicator and the pen pressure on the coordinate input surface by the position indicator are detected by the coordinate input device. In addition, since the handwriting verification is performed using the standardized handwriting information obtained by sampling and standardizing the coordinate values and the writing pressure, the shape and writing pressure of the character signed on the coordinate input surface are detected and compared. This makes it possible to determine whether or not the handwriting is registered in advance.

According to claim (2), in addition to the above-described effects, the tuning circuit of the position indicator has a coil and a capacitor as main components and does not require a cable or the like. Since heavy parts such as magnets are not required, and therefore, the operability at the time of input is good, characters similar to normal characters can be drawn.

According to the third aspect, since the coordinate value and the pen pressure that change with time are detected using the change of the tuning frequency in the tuning circuit of the position indicator, the position indicator is used to detect the writing pressure on the tablet. Since the character is read when the character is drawn with, it is difficult to intentionally draw the character in a similar shape, stroke order, and writing pressure. Therefore, it is possible to confirm the identity of the user by checking the handwriting of the signature.

Furthermore, by disseminating the handwriting verification device of the present invention widely, there is an advantage that it is not necessary to carry a credit card or the like, and it is possible to prevent misuse of a lost credit card or the like.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a handwriting collation device of the present invention, FIG. 2 is a detailed configuration diagram of a loop coil group in the X direction and the Y direction of the tablet, and FIG. 3 is a cross-sectional view of a position indicator. ,
FIG. 4 is a signal waveform diagram of each part in FIG. 1, FIG. 5 is a flowchart of a process in the control circuit, and FIGS. 6 (a), (b) and (c) are timings showing a basic coordinate detecting operation in the control circuit. FIG. 7 is a diagram showing a detection voltage obtained from each loop coil at the time of the first coordinate detection operation. FIG. 8 is a timing chart showing the coordinate detection operation and the phase detection operation after the second time. 9 is a flowchart of handwriting data registration processing in the host computer of one embodiment, FIG. 10 is a diagram showing an example of a signature drawn on a tablet, FIG. 11 is a diagram showing an example of sampling data in one embodiment, FIG. FIG. 12 is a diagram showing the relationship between time and standardized information in one embodiment, and FIG.
FIG. 11 is a flowchart of the handwriting data collation processing in the host computer of the embodiment. 10 ... tablet, 11 ... loop coil group in X direction, 12
…… Y-direction loop coil group, 20 …… Position indicator, 24…
... coils, 27 ... capacitors, 28 ... tuning circuits, 30 ...
Control circuit, 31 ... Signal generation circuit, 32 ... X direction selection circuit, 33 ... Y direction selection circuit, 34,35 ... Transmission / reception switching circuit, 36 ... XY switching circuit, 37 ... Reception timing switching Circuit, 38 Band filter, 39 Detector, 40, 43, 44
Low-pass filters, 41, 42: Phase detector, 49: Host computer, 50: Main storage device, 51: Memory required for calculation,
52 Display device.

Claims (3)

(57) [Claims] A coordinate input device having means for detecting a coordinate value of a position designated on a coordinate input surface by a position indicator and a pen pressure on the coordinate input surface by the position indicator; Sampling means for sampling coordinate values and writing pressure detected by the apparatus at predetermined time intervals and outputting as handwriting data composed of a plurality of sampling data; and, based on the handwriting data, input using the position indicator. Central coordinate calculating means for calculating the coordinates of the center point of the character string; distance calculating means for calculating the distance from the central coordinates calculated by the central coordinate calculating means to the respective coordinates of each sampled data; Average distance calculating means for calculating an average value of the plurality of distances calculated by the distance calculating means, and calculating the distance average value calculated by the average distance calculating means. And standardization information calculation means for calculating standardization information obtained by standardizing each of the plurality of distances calculated by the distance calculation means, corresponding to the pen pressure and the sampling data represented by each of the sampling data. The standardized handwriting information including the obtained standardized information is compared with the pre-registered standardized handwriting information, and the handwriting of the character string input using the position indicator is registered in advance. A handwriting collation device comprising: a handwriting judging means for judging whether or not the handwriting is the person's handwriting. 2. A coordinate input device comprising a plurality of loop coils X
A tablet comprising a group of loop coils in the X direction arranged side by side in the direction and a group of loop coils in the Y direction formed by arranging a number of loop coils side by side in the Y direction; and at least a coil and a capacitor. A position indicator having a tuning circuit in which a tuning frequency changes around a predetermined frequency; an X-direction selecting means for sequentially selecting one loop coil from a group of loop coils in the X direction of the tablet; and a Y direction of the tablet. Selecting means in the Y direction for sequentially selecting one loop coil from the group of loop coils; signal generating means for generating the AC signal of the predetermined frequency; signal detecting means for detecting the AC signal of the predetermined frequency; The AC signal detected by the signal detection means from each of the X-direction and Y-direction loop coils selected by the X-direction and Y-direction selection means Zui by the position indicator handwriting collating apparatus according to claim 1, wherein constructed from a coordinate detecting means for determining the X and Y directions of the input coordinate by. 3. The method according to claim 1, wherein a change in a tuning frequency in a tuning circuit of the position indicator is detected based on an AC signal detected by the signal detecting means from one of the loop coils in the X direction or the Y direction. 3. The handwriting verification device according to claim 2, wherein the change in phase is detected as a change in the pen pressure, and the change in the phase is used as the pen pressure.