JP2012220972A - Signature authentication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a signature authentication apparatus for determining the authenticity of a signature by detecting and processing reflected light to obtain specific information based on the three-dimensional position of a pen.SOLUTION: A pen type input device used in a signature authentication apparatus includes: a detection section 200 for detecting reflected light; a processing section 300 for performing processing based on the detection result of the detection section 200. The input device has at least one of a first reflection section RE1 having a reflectance varying in the longitudinal direction and a second reflection section RE2 having a reflectance varying in the rotational direction around an axis along the longitudinal direction. The detection section 200 detects reflected light from at least one of the first reflection section RE1 and the second reflection section RE2. The processing section 300 obtains at least one of movement amount information of the first reflection section RE1 in the longitudinal direction and rotation amount information of the second reflection section RE2 in the rotational direction.

Description

  The present invention relates to an authentication system for identifying authenticity of handwritten data such as a signature.

Conventionally, as disclosed in US Pat. No. 5,123,064 (Patent Document 2), US Pat. No. 5,448,044 (Patent Document 3), etc., many electronic signature authentication devices called signature pads have been sold by various companies. These are generally used to read handwriting data on a flat surface, but in recent years, techniques for reading handwriting in three dimensions have been proposed.
Although there is no detailed description in Patent Document 1, the above-described signature authentication system can detect a three-dimensional position, so that, for example, the tilt of a pen at the time of signature can also be detected. In other words, since the signature of the individual who signs can be read, it can be said that the three-dimensional detection can improve the reliability more than the signature authentication of only the handwriting data on the plane.

JP 2009-9280 A US Pat. No. 5,123,064 US Pat. No. 5,448,044

However, since the book name authentication system disclosed in Patent Document 1 uses image data acquired by a stereo camera, a huge amount of data is required for CPU data processing. Acquiring image data also acquires a lot of data other than the data that is actually necessary for signature authentication, for example, background images and arm images. Reliability is reduced.
Therefore, an object of the present invention is to provide a signature authentication device that reads the movement of the pen three-dimensionally without acquiring captured image data with a camera or the like, or for each signer obtained by the three-dimensional movement of the pen. An object of the present invention is to provide a signature authentication apparatus that reads information unique to a signer.

(1)
One aspect of the present invention is a signature authentication system, a writing instrument for handwriting, an irradiation unit that emits irradiation light to the writing instrument, and detection for detecting reflected light reflected by the writing instrument. A processing unit that performs processing based on the detection result of the detection unit, a storage unit that stores specific information, a verification unit that collates information processed by the processing unit and the specific information, The writing instrument includes: a first reflective portion having a different reflectance in a longitudinal direction of the writing instrument; and a second reflection having a different reflectance in a rotation direction around an axis along the longitudinal direction. The detection unit detects reflected light from at least one of the first reflection unit and the second reflection unit, and the processing unit detects the detection result of the detection unit. Based on the longitudinal direction of the first reflective portion And obtaining at least one of the rotation amount information in the amount of movement information and the rotation direction of the second reflection portions in.
According to the said structure, a writing instrument has at least one of a 1st reflection part and a 2nd reflection part, and is the movement amount information in the longitudinal direction of a 1st reflection part, and the rotation direction of a 2nd reflection part. At least one of the rotation amount information can be obtained. Therefore, it is possible to acquire three-dimensional movement information such as the inclination of the writing instrument.

(2)
In one embodiment of the present invention, the first reflecting portion gradually changes in reflectance in the longitudinal direction of the writing instrument, and the second reflecting portion is an axis of the axis along the longitudinal direction. A configuration may be adopted in which the reflectance gradually changes in the surrounding rotation direction.
According to the above configuration, since the writing tool whose reflectance gradually changes in the longitudinal direction or the rotation direction can be used, the movement of the writing tool can be obtained with high accuracy.

(3)
In the aspect of the invention, the processing unit may obtain a movement locus of the writing instrument based on a detection result of reflectance at the first reflecting unit.
According to the above configuration, the handwriting of the person who signs can be obtained. For example, it is possible to determine whether the handwriting is image data such as bitmap data using the handwriting authentication software.

The block diagram which shows the basic composition of the signature authentication system of this embodiment. The block diagram which further subdivided the block diagram of FIG. 2 is a configuration example of a pen-type input device that can be used in the present embodiment. The structural example of a light-receiving part. 5A and 5B are configuration examples of the light receiving unit. The structural example of an irradiation part. 7A and 7B are diagrams illustrating a coordinate information detection method. 8A and 8B show signal waveform examples of the light emission control signal. The other example of a structure of an irradiation part. The structural example of the writing instrument used by this embodiment. An example of a writing instrument by using a stretchable member. The example which detects the pushing amount of a writing instrument by providing a detection area. The block diagram of a pen type input device. The structural example of a detection part. FIGS. 15A and 15B are diagrams illustrating an example in which three light receiving units are provided. FIGS. 16A and 16B are prediction examples of the position of the writing tool based on the acquisition of three-dimensional coordinate information. Signal waveform example of authentication factor.

Hereinafter, this embodiment will be described. In addition, this embodiment demonstrated below does not unduly limit the content of this invention described in the claim. In addition, all the configurations described in the present embodiment are not necessarily essential configuration requirements of the present invention.
FIG. 1 is a block diagram showing a basic configuration of a signature authentication system according to an embodiment of the present invention. The signature authentication system includes a pen-type input device 1, an authentication factor extraction / generation unit 2 that extracts and generates an authentication factor for authentication of handwriting data from information obtained by the pen-type input device 1, an authentication factor A reference data registration unit 3 that stores handwriting of each individual obtained by the extraction / generation unit 2 as reference data, a database that stores a plurality of reference data for each individual, and an authentication factor extracted in the authentication mode, It is composed of an authentication unit 5 that verifies the reference data of the database 4 and authenticates authenticity. The true / false result is output via an API (Application Program Interface) 6.
Here, the authentication factor is data obtained by calculating the movement of the pen tip, which is a handwriting, the tilt of the pen, and the speed of the pen from the XYZ coordinates.

  FIG. 2 is a block diagram in which the apparatus of FIG. 1 is subdivided based on functions. The pen movement information capture (1a) captures the three-dimensional position of the pen in time series. Furthermore, the information about the rotation of the pen around the pen axis is taken in time series by taking the pen rotation information (1b). The pen movement information undergoes pen position analysis (2a), and performs pen tip locus extraction (2c) and pen tilt extraction (2d). Further, the pen movement information is subjected to pen speed analysis (2b), and pen speed extraction (2e) is performed. Based on the pen rotation information, pen rotation extraction (2f) is performed. The pen tip locus, pen tilt, pen speed, and pen rotation are normalized (2g).

  In the registration mode, feature data is extracted (3) from the normalized data. This characteristic data is unique information for each signer, that is, it can be said to be profile data of a book title. This feature data is composed of a plurality of authentication factors such as a pen tip movement locus, a pen tilt, and a pen speed. It is desirable to authenticate the signature by emphasizing the pen inclination when the handwriting is a person who always holds the pen and the pen inclination is constant according to the personal habit. In addition, in the case of a person who moves the pen quickly with the individual's trap, it is desirable to authenticate the signature with an emphasis on the pen speed. In this embodiment, a feature function parameter is set as a parameter for performing such weighting. For example, if the normalized data is written by writing the same signature three times to the signer, three signer-specific profile data can be obtained. This finds the person's trap and generates feature function parameters. The average value of the three profile data is used as reference data. Then, the feature function parameter and the reference data are registered in the database 4.

  In the authentication mode, profile extraction is performed by performing feature extraction (5a) using a normalized extraction factor. Since the signature is usually once in the authentication mode, the profile data is created from one signature operation. Then, comparison (5b) with the reference data of the database 4 is performed, but the book title is not always the same, so when comparing the profile data of one signature with the reference data, May lead to the wrong conclusion that you are not. Therefore, an allowable range of difference is set by the feature function parameter. Thereby, highly reliable signature authentication is possible.

  In the signature authentication system of the present embodiment, the tilt of the pen is also considered as an authentication factor. The right-handed person and the left-handed person have completely opposite pen tilts. Therefore, in the signature authentication system of this embodiment, the possibility of making a right-handed person and a left-handed person mistakenly decreases. This is a feature that cannot be achieved by the two-dimensional signature authentication system, and is a great advantage of the signature authentication system of the present embodiment.

FIG. 3 shows a basic configuration example of the optical position detection apparatus 100 that can be used in the pen-type input device 1 according to the present embodiment. The optical position detection apparatus 100 in FIG. 3 includes a detection unit 200 and a processing unit 300, and the detection unit 200 includes an irradiation unit EU and a light receiving unit RU.
Note that the pen-type input device 1 is not limited to the form realized using the optical position detection device 100 including the detection unit 200 and the processing unit 300 as described above. The functions of the detection unit 200 and the processing unit 300 may be realized by an information processing device (such as a PC), and the irradiation unit EU and the light receiving unit RU and the information processing device may operate in conjunction with each other.

The detection unit 200 detects information (for example, coordinate information and reflectance information) of the writing tool OB based on the light reception result of the reflected light LR due to the irradiation light LT reflected by the writing tool OB (pen). Specifically, for example, when the detection area RDET, which is an area where the writing instrument OB is detected, is an area along the XY plane, the detection unit 200 at least X of the writing instrument OB present in the detection area RDET. Coordinate information and Y coordinate information are detected. A method for detecting coordinate information by the detection unit 200 will be described later. Specifically, reflectance information, which is information relating to the reflectance of the writing instrument OB, is detected.
The detection area RDET is an area (area) where the writing tool OB is detected. Specifically, for example, the light receiving unit RU receives reflected light LR caused by the irradiation light LT being reflected by the writing tool OB. This is the area where the writing instrument OB can be detected. More specifically, it is an area where the light receiving unit RU can receive the reflected light LR and detect the writing instrument OB, and the detection accuracy can be ensured within an acceptable range.

The processing unit 300 performs various processes based on the object information detected by the detection unit 200. The function of the processing unit 300 can be realized by a processor such as a CPU, a program executed by the processor, a dedicated IC, or the like.
The irradiation unit EU emits irradiation light LT to the detection area RDET. As will be described later, the irradiation unit EU includes a light source unit composed of a light emitting element such as an LED (light emitting diode), and emits, for example, infrared light (near infrared ray close to the visible light region) when the light source unit emits light. .
The light receiving unit RU receives the reflected light LR generated by the irradiation light LT being reflected by the writing instrument OB. The light receiving unit RU may include a plurality of light receiving units PD. For example, a photodiode or a phototransistor can be used as the light receiving unit PD.

  FIG. 4 shows a specific configuration example of the light receiving unit RU of the present embodiment. In the configuration example of FIG. 4, the light receiving unit RU includes a light receiving unit PD. The light receiving unit PD is provided with a slit or the like (incident light limiting unit) for limiting the angle (incident on the YZ plane) on which incident light is incident, and the reflected light from the writing instrument OB present in the detection area RDET. LR is received. The detection unit 200 detects X coordinate information and Y coordinate information based on the light reception result of the light receiving unit PD. The irradiation unit EU emits irradiation light LT to the detection area RDET. The detection area RDET is an area along the XY plane. In addition, although the structural example of FIG. 4 is comprised with one light receiving unit, it is good also as a structure containing two or more light receiving units.

FIGS. 5A and 5B show a configuration example of the light receiving unit PD having the slit SLT (incident light limiting unit). As shown in FIG. 5A, a slit SLT is provided in front of the light receiving element PHD to limit incident incident light. The slit SLT is provided along the XY plane, and can limit the angle in the Z direction where incident light is incident. That is, the light receiving unit PD can receive incident light incident at a predetermined angle defined by the slit width of the slit SLT.
FIG. 5B is a plan view seen from above of the light receiving unit having the slit SLT. For example, a wiring board PWB is provided in a housing (case) such as aluminum, and the light receiving element PHD is mounted on the wiring board PWB.

  In FIG. 6, the detailed structural example of the irradiation part EU of this embodiment is shown. The irradiation unit EU in the configuration example of FIG. 6 includes light source units LS1 and LS2, a light guide LG, and an irradiation direction setting unit LE. Moreover, the reflective sheet RS is included. The irradiation direction setting unit LE includes the optical sheet PS and the louver film LF. Note that the irradiation unit EU of the present embodiment is not limited to the configuration of FIG. 6, and various components such as omitting some of the components, replacing them with other components, and adding other components. Variations are possible.

  The light source units LS1 and LS2 emit light source light and have light emitting elements such as LEDs (light emitting diodes). The light source units LS1 and LS2 emit, for example, infrared light (near infrared light close to the visible light region). That is, the light source light emitted from the light source units LS1 and LS2 has a wavelength band that is not included in the wavelength band light that is efficiently reflected by an object such as a user's finger or a touch pen, or ambient light that becomes disturbance light. It is desirable to be light. Specifically, infrared light with a wavelength near 850 nm, which is light in a wavelength band with high reflectance on the surface of the human body, infrared light near 950 nm, which is light in a wavelength band that is not so much included in environmental light, etc. It is.

  The light source unit LS1 is provided on one end side of the light guide LG as indicated by F1 in FIG. The second light source unit LS2 is provided on the other end side of the light guide LG as indicated by F2. Then, the light source unit LS1 emits the light source light to the light incident surface on one end side (F1) of the light guide LG, thereby emitting the irradiation light LT1, and detecting the first irradiation light intensity distribution LID1. Form (set) the area. On the other hand, the light source unit LS2 emits the second light source light LT2 by emitting the second light source light to the light incident surface on the other end side (F2) of the light guide LG, so that the first irradiation light is emitted. A second irradiation light intensity distribution LID2 having an intensity distribution different from that of the intensity distribution LID1 is formed in the detection area. In this way, the irradiation unit EU can emit irradiation light having different intensity distributions according to the position in the detection area RDET.

The light guide LG (light guide member) guides the light source light emitted from the light source units LS1 and LS2. For example, the light guide LG guides the light source light from the light source units LS1 and LS2 along a curved light guide path, and the shape thereof is a curved shape. Specifically, in FIG. 6, the light guide LG has an arc shape. In FIG. 6, the light guide LG has an arc shape with a center angle of 180 degrees, but may have an arc shape with a center angle smaller than 180 degrees. The light guide LG is formed of, for example, a transparent resin member such as acrylic resin or polycarbonate.
At least one of the outer peripheral side and the inner peripheral side of the light guide LG is processed to adjust the light output efficiency of the light source light from the light guide LG. As a processing method, for example, various methods such as a silk printing method for printing reflective dots, a molding method for forming irregularities with a stamper or injection, and a groove processing method can be adopted.

  The irradiation direction setting unit LE realized by the prism sheet PS and the louver film LF is provided on the outer peripheral side of the light guide LG and receives light source light emitted from the outer peripheral side (outer peripheral surface) of the light guide LG. And the irradiation light LT1 and LT2 in which the irradiation direction was set to the direction which goes to the outer peripheral side from the inner peripheral side of the light guide LG of curved shape (arc shape) are radiate | emitted. That is, the direction of the light source light emitted from the outer peripheral side of the light guide LG is set (restricted) to an irradiation direction along, for example, the normal direction (radial direction) of the light guide LG. Thereby, irradiation light LT1 and LT2 come to radiate | emit radially in the direction which goes to the outer peripheral side from the inner peripheral side of the light guide LG.

  Such setting of the irradiation direction of the irradiation light LT1, LT2 is realized by the prism sheet PS, the louver film LF, or the like of the irradiation direction setting unit LE. For example, the prism sheet PS sets the direction of the light source light emitted at a low viewing angle from the outer peripheral side of the light guide LG to the normal direction side so that the peak of the light emission characteristic is in the normal direction. The louver film LF blocks (cuts) light in a direction other than the normal direction (low viewing angle light).

  As described above, according to the irradiation unit EU of the present embodiment, the light source portions LS1 and LS2 are provided at both ends of the light guide LG, and the light source portions LS1 and LS2 are alternately turned on to thereby generate two irradiation light intensity distributions. Can be formed. That is, the irradiation light intensity distribution LID1 in which the intensity on one end side of the light guide LG is increased and the irradiation light intensity distribution LID2 in which the intensity on the other end side of the light guide LG is increased can be alternately formed.

  By forming such irradiation light intensity distributions LID1 and LID2 and receiving the reflected light of the object by the irradiation light of these intensity distributions, the influence of ambient light such as ambient light is minimized. It is possible to detect an object having a high height. That is, it is possible to cancel out the infrared component included in the disturbance light, and it is possible to minimize the adverse effect of the infrared component on the detection of the object.

<Coordinate detection method using optical position detector>
FIGS. 7A and 5B are diagrams for explaining a method of detecting coordinate information by the optical position detection device 100 that can be used in the pen-type input device 1 according to the present embodiment.
E1 in FIG. 7A is a diagram showing the relationship between the irradiation direction angle of the irradiation light LT1 and the intensity of the irradiation light LT1 at that angle in the irradiation light intensity distribution LID1 of FIG. At E1 in FIG. 7A, the intensity is highest when the irradiation direction is the direction DD1 in FIG. 7B (left direction). On the other hand, the intensity is lowest when the direction is DD3 (right direction), and the intensity is intermediate in the direction DD2. Specifically, the intensity of the irradiation light monotonously decreases with respect to the angle change from the direction DD1 to the direction DD3, for example, changes linearly (linearly). In FIG. 7B, the center position of the arc shape of the light guide LG is the arrangement position PE of the irradiation unit EU.

  Further, E2 in FIG. 7A is a diagram showing the relationship between the angle of the irradiation direction of the irradiation light LT2 and the intensity of the irradiation light LT2 at that angle in the irradiation light intensity distribution LID2 of FIG. At E2 in FIG. 7A, the intensity is highest when the irradiation direction is the direction of DD3 in FIG. 7B. On the other hand, the intensity is the lowest in the direction of DD1, and the intermediate intensity in the direction of DD2. Specifically, the intensity of irradiation light monotonously decreases with respect to an angle change from the direction DD3 to the direction DD1, and changes linearly, for example. In FIG. 7A, the relationship between the angle in the irradiation direction and the intensity is linear, but the present embodiment is not limited to this, and may be a hyperbolic relationship, for example.

  Then, as shown in FIG. 7B, it is assumed that the writing instrument OB exists in the direction DDB of the angle φ. Then, when the irradiation light intensity distribution LID1 is formed by the light source unit LS1 emitting light (in the case of E1), as shown in FIG. 7A, the writing instrument OB present in the direction of DDB (angle φ). The intensity at the position is INTa. On the other hand, when the irradiation light intensity distribution LID2 is formed by light emission from the light source unit LS2 (in the case of E2), the intensity at the position of the writing instrument OB existing in the direction of DDB is INTb.

  Therefore, the direction DDB (angle φ) in which the writing instrument OB is located can be specified by obtaining the relationship between the strengths INTa and INTb. For example, if the distance of the writing instrument OB from the position PE of the optical position detection device is obtained by the method shown in FIGS. 8A and 8B described later, writing is performed based on the obtained distance and the direction DDB. The position of the tool OB can be specified. Alternatively, as shown in FIG. 9 to be described later, two irradiation units EU1 and EU2 are provided as the irradiation unit EU, and directions DDB1 (φ1) and DDB2 (φ2) of the writing instrument OB with respect to each irradiation unit of EU1 and EU2 are obtained. For example, the position of the writing instrument OB can be specified by the directions DDB1 and DDB2 and the distance DS between the irradiation units EU1 and EU2.

  In order to obtain such a relationship between the intensity INTa and INTb, in this embodiment, the light receiving unit RU receives the reflected light (first reflected light) of the writing instrument OB when the irradiation light intensity distribution LID1 is formed. . If the detected light reception amount of the reflected light at this time is Ga, this Ga corresponds to the intensity INTa. The light receiving unit RU receives the reflected light (second reflected light) of the writing instrument OB when the irradiation light intensity distribution LID2 is formed. When the detected light reception amount of the reflected light at this time is Gb, this Gb corresponds to the intensity INTb. Therefore, if the relationship between the detected light reception amounts Ga and Gb is obtained, the relationship between the intensity INTa and INTb can be obtained, and the direction DDB in which the writing instrument OB is located can be obtained.

For example, the control amount (for example, current amount), the conversion coefficient, and the emitted light amount of the light source unit LS1 are Ia, k, and Ea, respectively. In addition, the control amount (current amount), the conversion coefficient, and the amount of emitted light of the light source unit LS2 are Ib, k, and Eb, respectively. Then, the following expressions (1) and (2) are established.
Ea = k · Ia (1)
Eb = k · Ib (2)

Further, let fa be the attenuation coefficient of the light source light (first light source light) from the light source unit LS1, and let Ga be the detected received light amount of the reflected light (first reflected light) corresponding to this light source light. Further, the attenuation coefficient of the light source light (second light source light) from the light source unit LS2 is fb, and the detected light reception amount of the reflected light (second reflected light) corresponding to the light source light is Gb. Then, the following expressions (3) and (4) are established.
Ga = fa · Ea = fa · k · Ia (3)
Gb = fb · Eb = fb · k · Ib (4)
Therefore, the ratio of the detected light reception amounts Ga and Gb can be expressed as the following equation (5).
Ga / Gb = (fa / fb). (Ia / Ib) (5)

  Here, Ga / Gb can be specified from the light reception result in the light receiving unit RU, and Ia / Ib can be specified from the control amount of the irradiation unit EU. Intensities INTa and INTb and attenuation coefficients fa and fb in FIG. 5A are in a unique relationship. For example, when the attenuation coefficients fa and fb are small values and the attenuation is large, it means that the strengths INTa and INTb are small. On the other hand, when the attenuation coefficients fa and fb are large and the attenuation is small, it means that the strengths INTa and INTb are large. Therefore, the direction, position, etc. of the object can be obtained by obtaining the attenuation factor ratio fa / fb from the above equation (5).

  More specifically, one control amount Ia is fixed to Im, and the other control amount Ib is controlled so that the detected light reception amount ratio Ga / Gb becomes 1. For example, the light source units LS1 and LS2 are controlled to turn on alternately in reverse phase, the detected received light amount waveform is analyzed, and the other control is performed so that the detected waveform is not observed (Ga / Gb = 1). The amount Ib is controlled. Then, from the other control amount Ib = Im · (fa / fb) at this time, the ratio fa / fb of the attenuation coefficient is obtained, and the direction, position, etc. of the object are obtained.

Further, as in the following formulas (6) and (7), control may be performed so that Ga / Gb = 1 and the sum of the control amounts Ia and Ib is constant.
Ga / Gb = 1 (6)
Im = Ia + Ib (7)
Substituting the above equations (6) and (7) into the above equation (5), the following equation (8) is established.
Ga / Gb = 1 = (fa / fb) · (Ia / Ib)
= (Fa / fb) · {(Im−Ib) / Ib} (8)
From the above equation (8), Ib is expressed as the following equation (9).
Ib = {fa / (fa + fb)} · Im (9)
Here, if α = fa / (fa + fb), the above equation (9) is expressed as the following equation (10), and the attenuation coefficient ratio fa / fb is expressed by the following equation (11) using α. It is expressed in
Ib = α · Im (10)
fa / fb = α / (1-α) (11)

  Therefore, if Ga / Gb = 1 and control is performed so that the sum of Ia and Ib becomes a constant value Im, α is obtained from the current Ib and Im by the above equation (10), and the obtained α is increased. By substituting into Equation (11), the ratio fa / fb of the attenuation coefficient can be obtained. This makes it possible to obtain the direction, position, etc. of the object. Further, by controlling so that Ga / Gb = 1 and the sum of Ia and Ib becomes constant, it becomes possible to cancel the influence of disturbance light and the like, and the detection accuracy can be improved.

Next, an example of a method for detecting coordinate information of an object using the optical detection system of the present embodiment will be described. FIG. 8A is an example of a signal waveform for light emission control of the light source units LS1 and LS2. The signal SLS1 is a light emission control signal of the light source unit LS1, the signal SLS2 is a light emission control signal of the light source unit LS2, and these signals SLS1 and SLS2 are in reverse phase. The signal SRC is a light reception signal.
For example, the light source unit LS1 is turned on (emits light) when the signal SLS1 is at the H level, and is turned off when the signal SLS1 is at the L level. The light source unit LS2 is turned on (emits light) when the signal SLS2 is at the H level, and is turned off when the signal SLS2 is at the L level. Accordingly, in the first period T1 in FIG. 8A, the light source unit LS1 and the light source unit LS2 are alternately turned on. That is, the light source unit LS2 is turned off during the period when the light source unit LS1 is turned on. Thereby, an irradiation light intensity distribution LID1 as shown in FIG. 6 is formed. On the other hand, the light source unit LS1 is turned off during the period when the light source unit LS2 is turned on. Thereby, an irradiation light intensity distribution LID2 as shown in FIG. 6 is formed.

  As described above, the detection unit 200 performs control of alternately emitting (lighting) the light source unit LS1 and the light source unit LS2 in the first period T1. And in this 1st period T1, the direction where the target object located seen from the optical position detection apparatus (irradiation part) is detected. Specifically, for example, in the first period T1, light emission control is performed such that Ga / Gb = 1 and the sum of the control amounts Ia and Ib is constant as in the above-described formulas (6) and (7). Do. Then, as shown in FIG. 7B, the direction DDB in which the writing instrument OB is located is obtained. For example, the ratio fa / fb of the attenuation coefficient is obtained from the above equations (10) and (11), and the direction DDB in which the writing instrument OB is located is obtained by the method described in FIGS. 7 (A) and 7 (B).

Then, in the second period T2 following the first period T1, the distance to the writing instrument OB (the distance in the direction along the direction DDB) is detected based on the light reception result of the light receiving unit RU. Then, the position of the object is detected based on the detected distance and the direction DDB of the writing instrument OB. That is, in FIG. 7B, the X and Y coordinate positions of the writing tool OB can be specified by obtaining the distance from the arrangement position PE of the optical position detection device to the writing tool OB and the direction DDB in which the writing tool OB is located. . In this manner, the position of the writing instrument OB can be specified by obtaining the distance from the time difference between the lighting timing of the light source and the light receiving timing and combining this with the angle result.
Specifically, in FIG. 8A, a time Δt from the light emission timing of the light source units LS1 and LS2 by the light emission control signals SLS1 and SLS2 to the timing when the light reception signal SRC becomes active (the timing when the reflected light is received) is detected. To do. That is, the time Δt from when the light from the light source units LS1 and LS2 is reflected by the writing instrument OB and received by the light receiving unit RU is detected. By detecting this time Δt, since the speed of light is known, the distance to the writing instrument OB can be detected. That is, the shift width (time) of the arrival time of light is measured, and the distance is obtained from the speed of light.

In addition, since the speed of light is quite high, there is also a problem that it is difficult to detect the time Δt by obtaining a simple difference using only an electric signal. In order to solve such a problem, it is desirable to modulate the light emission control signal as shown in FIG. Here, FIG. 8B is a schematic signal waveform example schematically representing light intensity (current amount) by the amplitude of the control signals SLS1 and SLS2.
Specifically, in FIG. 8B, the distance is detected by, for example, a known continuous wave modulation TOF (Time Of Flight) method. In this continuous wave modulation TOF method, continuous light that is intensity-modulated with a continuous wave having a constant period is used. Then, while irradiating the intensity-modulated light and receiving the reflected light a plurality of times at time intervals shorter than the modulation period, the waveform of the reflected light is demodulated and the phase difference between the irradiated light and the reflected light is obtained. Thus, the distance is detected. In FIG. 8B, the intensity of only the light corresponding to one of the control signals SLS1 and SLS2 may be modulated. Further, instead of the clock waveform as shown in FIG. 8B, a waveform modulated by a continuous triangular wave or Sin wave may be used. Further, the distance may be detected by a pulse modulation TOF method using pulsed light as continuously modulated light. Details of the distance detection method are disclosed in, for example, Japanese Patent Application Laid-Open No. 2009-8537.

  In FIG. 9, the modification of the irradiation part EU of this embodiment is shown. In FIG. 9, first and second irradiation units EU1 and EU2 are provided as the irradiation unit EU. These first and second irradiation units EU1, EU2 are arranged apart by a given distance DS in the direction along the surface of the detection area RDET of the writing instrument OB. That is, they are arranged apart by a distance DS along the X-axis direction in FIG.

The first irradiation unit EU1 emits first irradiation light having different intensities according to the irradiation direction radially. The second irradiation unit EU2 emits second irradiation light having different intensities according to the irradiation direction radially. The light receiving unit RU writes the first reflected light from the first irradiation light from the first irradiation unit EU1 reflected by the writing tool OB and the second irradiation light from the second irradiation unit EU2. Second reflected light is received by being reflected by the tool OB. Then, the detection unit 200 detects the position POB of the writing instrument OB based on the light reception result at the light receiving unit RU.
Specifically, the detection unit 200 detects the direction of the writing instrument OB relative to the first irradiation unit EU1 as the first direction DDB1 (angle φ1) based on the light reception result of the first reflected light. Further, based on the reception result of the second reflected light, the direction of the writing instrument OB relative to the second irradiation unit EU2 is detected as the second direction DDB2 (angle φ2). Then, based on the detected first direction DDB1 (φ1) and second direction DDB2 (φ2), and the distance DS between the first and second irradiation units EU1, EU2, the position POB of the writing instrument OB. Ask for.

  According to the modification of FIG. 9, the position POB of the writing tool OB can be detected without obtaining the distance between the optical position detection device and the writing tool OB as shown in FIGS. 8A and 8B. It becomes like this.

<Acquisition of 3D position information of pen-type input device>
Next, a method for acquiring the three-dimensional position information of the pen-type input device 1 will be described.
An example of a writing instrument used in this embodiment is shown in FIG. In addition, the enlarged view of the reflection part provided in the pattern part of a writing instrument is also shown.

  As shown in FIG. 10, the writing instrument includes a reflecting member (first reflecting portion RE1) having a different reflectance in the longitudinal direction, and a reflecting member having a different reflectance in the rotational direction around the axis along the longitudinal direction. (Second reflection unit RE2). Based on the reflected light from the first reflecting part RE1 provided in the longitudinal direction, a moving amount (pushing amount) in the longitudinal direction is obtained, and based on the reflected light from the second reflecting part RE2 provided in the rotating direction. Thus, the rotation amount in the rotation direction is obtained.

  A plurality of methods can be considered for the structure for detecting the movement amount in the longitudinal direction. For example, as shown in FIG. 11, a method of dividing the writing instrument into a first part and a second part and connecting the first part and the second part with a stretchable material such as a spring can be considered. Even in this case, since the spring contracts, it is possible to further push the writing instrument in the direction of the target surface from the state where the pen tip is in contact with the target surface, and thus the amount of movement in the longitudinal direction can be obtained. Furthermore, the writing material which does not use a deformable material or a spring mechanism as described above may be used. In this case, for example, characters can be input even when the pen tip is lifted from the target surface. For example, as shown in FIG. 12, a certain Z coordinate range from the target surface is defined as the input range, and input is performed when a writing tool exists in the input range. And the Z coordinate information (for example, Z coordinate information of a pen point part) of the writing instrument in that case is calculated | required, and the movement amount in a longitudinal direction should just be calculated | required from the magnitude of the coordinate information.

<Configuration example of light receiving unit>
Next, a configuration example of the light receiving unit of the optical position detection apparatus 100 will be described. Here, the light receiving unit included in the light receiving unit RU in the detection unit 200 as illustrated in FIG. 13 will be described, but in detail, the first detection included in the detection unit 200 as illustrated in FIG. The unit 210, the second detection unit 220, and the like. The first detector 210 detects the reflected light from the first reflector RE1, and the second detector 220 detects the reflected light from the second reflector RE2. Further, as shown in FIG. 13, the first detection unit 210 may include a first part detection unit 211, a second part detection unit 212, and the like.

  In the description of the optical position detection device 100 described above, there is one light receiving unit. However, in this embodiment, a plurality of light receiving units are used. As described above, the light receiving unit used in the present embodiment is premised on that the light receiving range (here, the Z coordinate range) is narrowly limited in order to improve position detection accuracy.

  A configuration example of the light receiving unit is shown in FIG. In the present embodiment, a plurality of light receiving units are provided at different positions on the Z coordinate axis. Here, an example in which three light receiving units are particularly provided will be described. Among the light receiving units provided at different positions on the Z coordinate axis, one necessary for obtaining the movement amount in the longitudinal direction is one light receiving unit that receives the reflected light from the first reflecting portion RE1 provided in the longitudinal direction. It is. Further, what is necessary for obtaining the amount of rotation in the rotation direction is one light receiving unit that receives the reflected light from the second reflection unit RE2 provided in the rotation direction. Further, when the inclination (and pointing position) of the writing instrument is obtained, the light received from two different points can be received from either the first reflection part RE1 or the second reflection part RE2. A unit is required. Therefore, if one of the two light receiving units for obtaining the inclination is used also as the light receiving unit for obtaining the movement amount information in the longitudinal direction and the other is also used for the light receiving unit for obtaining the rotation amount information in the rotation direction, When obtaining the movement amount information in the longitudinal direction, the rotation amount information in the rotation direction, and the inclination, it is sufficient to have a total of two light receiving units.

  However, as shown in FIG. 10, the second reflection part RE2 for detecting the rotation amount is arranged in a narrow region in the longitudinal direction so as to be distinguished from the first reflection part RE1. That is, in view of the case where the writing instrument is used standing on the target surface 20, the longitudinal direction is a direction corresponding to the Z-axis direction. RE1 is arranged in a narrow range in the Z coordinate. As described in the configuration example of the writing instrument, since the writing instrument is assumed to move to some extent in the longitudinal direction, the second of the writing instrument is moved in the longitudinal direction (including expansion and contraction of the spring mechanism). There is a possibility that the reflected light from the reflecting part RE2 of the light cannot be received by the light receiving unit.

  Therefore, in this embodiment, three light receiving units are provided at different positions on the Z coordinate axis. The first light receiving unit receives the reflected light from the first reflecting part RE1. In addition, the second light receiving unit and the third light receiving unit are provided at positions that take into account the amount of movement of the writing instrument in the longitudinal direction, and either the second light receiving unit or the third light receiving unit is the second light receiving unit. The reflected light from the reflection part RE2 is received. At that time, the light receiving unit that does not receive the reflected light from the second reflecting portion RE2 receives the reflected light from the first reflecting portion RE1. An example is shown in FIGS. 15A and 15B. As shown in FIG. 15A, the second light receiving unit is provided at the position (B2) for receiving the reflected light from the second reflecting portion RE2 in a state where the pushing amount is small, as shown in FIG. The third light receiving unit is provided at a position (D1) for receiving the reflected light from the second reflecting portion RE2 in a state where the pushing amount is large. In the state of FIG. 15A, the first light receiving unit (B3) and the third light receiving unit (B1) receive the reflected light from the first reflecting part RE1, and the amount of movement in the longitudinal direction is set. Then, the second light receiving unit (B2) receives the reflected light from the second reflecting part RE2, and obtains the rotation amount. Similarly, in the state of FIG. 15B, the first light receiving unit (D1) and the second light receiving unit (D2) receive the reflected light from the first reflecting part RE1 and move in the longitudinal direction. And the third light receiving unit (D1) receives the reflected light from the second reflecting portion RE2 to determine the amount of rotation.

  However, the configuration example of the light receiving unit is not limited to that described above. If the second reflecting part RE2 can be set in a wide range in the Z longitudinal direction, two light receiving units are sufficient. If one of the movement amount and the rotation amount in the longitudinal direction is to be obtained, it is sufficient to provide two light receiving units. Here, the reason for the two is that it is premised on the acquisition of the tilt information, and if it is not necessary to tilt the writing instrument, only one light receiving unit may be provided.

<Input data acquisition method>
Next, a method for acquiring input data will be described.
First, it is necessary to perform calibration for setting the reference position of the input position. Here, as a specific example, the reference position is a time when the writing instrument is completely pushed into the target surface direction.
Specifically, three pieces of reflectance information are acquired as calibration information based on the amount of light received by each light receiving unit when the writing instrument is completely pushed into the target surface.
Next, X coordinate information and Y coordinate information are acquired in each light receiving unit. The method for acquiring the coordinate information is as described above in the description of the optical position detection device. In an example using three light receiving units, the coordinate information (X1, Y1) is acquired in the first light receiving unit, the coordinate information (X2, Y2) is acquired in the second light receiving unit, and the third light receiving unit The coordinate information (X3, Y3) is acquired. Since the Z coordinate position where the first light receiving unit is provided is Z1, and the light receiving unit receives light in a narrow range in the Z coordinate, the coordinate information from the first light receiving unit is ( The three-dimensional information X1, Y1, Z1) is acquired. Similarly, (X2, Y2, Z2) is acquired from the second light receiving unit, and (X3, Y3, Z3) is acquired from the third light receiving unit. As a result, the inclination of the writing tool can be known (however, the writing tool is a straight bar), the contact position between the writing tool and the target surface (drawing surface) can be obtained, and the contact position is directly signed. It can be used as a position.

<Obtain reflectance information>
Even if three pieces of three-dimensional coordinate information are acquired, the amount of movement of the writing instrument in the longitudinal direction and the amount of rotation in the rotational direction cannot be obtained. This is because the above-described three-dimensional coordinate information only shows that the writing instrument exists at a position passing through the three points, and it is determined whether it is in the state of FIG. 16 (A) or FIG. 16 (B). It is not possible.

  Therefore, in this embodiment, the reflectance information of the 1st, 2nd reflection part provided in the writing instrument is acquired together. As described above, the reflectance of the first reflecting portion RE1 changes so as to draw a gradation in the longitudinal direction of the writing instrument. Therefore, by using reflectance information (specifically, a current value or the like in the light receiving unit), it is possible to determine to which part of the writing instrument the information detected by the light receiving unit corresponds. For example, if it is understood that the point of s1 [cm] exists at (X1, Y1, Z1) and the point of s2 [cm] exists at (X2, Y2, Z2) from the end of the writing instrument. The three-dimensional position of the writing instrument can be determined in detail. Similarly, the reflectance of the second reflecting portion RE2 changes so as to draw a gradation in the rotation direction around the axis along the longitudinal direction. Therefore, it can be determined which part of the writing instrument is facing the light receiving unit.

  Note that the method is not limited to the method of using the absolute value of the value represented by the reflectance information (such as the current value in the light receiving unit) as it is. Rather, when there is a factor such as a change in the intensity of the irradiation light in the irradiation unit EU, the current value changes as a whole, and thus using the absolute value of one value causes a problem. Therefore, reflectance information at two points in time may be acquired, and position information (amount of movement in the longitudinal direction, amount of rotation, etc.) may be obtained by comparison. Specifically, for example, a method using the above-described calibration value can be considered. A change from the value of the calibration information is detected on the basis of the calibration information. In the above-described example, since the completely pushed state is used as the reference position, it is possible to determine how much the moving or rotating state has been achieved from the completely pushed state based on the change from the calibration information.

  In addition, there is a possibility that a factor such as a change in irradiation light intensity may occur during the period from the calibration to the actual detection process. In that case, reflectance information at a certain time T1 and another time T2 may be detected, respectively, and the difference between the reflectance information at T1 and the reflectance information at T2 may be obtained. In this case, since it is not a comparison with the reference position, the absolute position of the writing instrument cannot be obtained, but the movement amount between T1 and T2 (for example, the movement amount in the longitudinal direction or the rotation in the rotation direction). Amount). At this time, if the interval between T1 and T2 is set to a sufficiently short interval, it is possible to suppress the influence of a change in the irradiation light intensity or the like.

<Signature authentication method>
As described above, since the pen-type input device 1 detects a three-dimensional pen position, an authentication factor is extracted based on the three-dimensional pen position information, and unique profile data for each signer is generated. Is done. FIG. 17 shows an example of data in which authentication factors that are the basis of this profile data are arranged in time series. This is, for example, an example in which “Yamada Hiroshi” is signed.

  Here, the pen tip position detection information PEN is a signal waveform in which the light receiving unit RU of the pen-type input device 1 displays the received light intensity detected at the time of signing by the signer in time series. By calculating the detection of the X-coordinate and Y-coordinate described above for this signal waveform, it is possible to calculate the change in the position of the tip of the writing instrument OB that is the pen tip, and as a result, a part of the signal waveform It can be determined that “Yamada” is written and “b” of the signal waveform is written “H”.

  The pen tilt information TIL is a signal waveform indicating a change in tilt of the writing instrument OB (pen) calculated by the pen type input device 1 in time series. This signal level has an almost constant value during the signing operation, and it can be seen that this signer has a tendency to sign with the pen tilt always kept constant. The pen speed information VEL indicates a value obtained by dividing the movement amount of the writing tool OB (pen) calculated by the pen type input device 1 by a unit time, that is, a change in the pen speed. The level of the signal is lower in the part b than in the part a. This shows that this signer is more apt to write the pen speed more slowly when writing the name "Hou" than when writing the last name "Yamada".

  The pen rotation information ROT displays the rotation speed of the writing instrument OB (pen) calculated by the pen type input device 1. Since there is almost no change in the signal level, it can be seen that the signature is made with almost no rotation of the pen. In the case of ballpoint pens and fountain pens, the pen is often not rotated, but in the case of brush pens, writing may be performed by rotating the pen, and detecting the rotation of the pen is useful for improving the authentication accuracy in signature authentication. Sometimes it becomes.

  In authenticating the signature, profile data is created from the authentication factor shown in FIG. The profile data is compared with the reference data. First, a handwriting image (for example, bitmap data) is generated from the pen tip position detection information PEN. Then, the handwriting image similarity is compared and compared with the handwriting image of the reference data. For comparison of the image data, handwriting authentication software or the like may be prepared.

In this embodiment, since the pen-type input device 1 can detect a three-dimensional position, it can create bit mat data of handwriting. In the above-described example, the position of the tip of the writing instrument OB (pen) is detected. The method of converting the image into a handwriting image and determining the authenticity from the shape of the handwriting image has been described.
However, it is not always necessary to create a handwriting image. When only the signature authentication is performed, it is also possible to compare the reflected light signal waveform itself without calculating the X coordinate and the Y coordinate which are the positions of the writing instrument OB (pen). That is, at the time of registration of the reference data, the signal waveform of the reflected light itself is registered as reference data, and at the time of authentication, the signal waveform when the signer performs a signature operation is used as profile data, and the profile data is compared with the reference data. . This is because the pen-type input device 1 used in the present embodiment uses a very characteristic light emission method, and the signal waveform of the intensity level of the light that reflects the emitted light with the writing instrument OB (pen) is a voiceprint. This can be realized because the personal-specific pattern can be directly used as profile data.

1 Pen-type input device 2 Authentication factor extraction / generation unit 3 Reference data registration unit
4 database, 5 authentication section,
20 target surface, 100 optical position detection device, 200 detection unit, 210 detection unit,
211, first part detection unit, 212 second part detection unit, 220 detection unit,
300 processing unit, EU irradiation unit, LE irradiation direction setting unit, LF louver film,
LG light guide, OB object, PD light receiving unit,
PD1 first light receiving unit, PD2 second light receiving unit,
PD3 Third light receiving unit, PHD light receiving element, PS prism sheet,
PS optical sheet, PWB wiring board, RE1 first reflection part, RE2 second reflection part,
RS reflection sheet, RU light receiving part, SLT slit,
PEN Position detection information.

Claims (3)

A writing instrument for handwriting,
An irradiation unit for emitting irradiation light to the writing instrument;
A detection unit for detecting reflected light reflected by the writing instrument with the irradiation light;
A processing unit that performs processing based on a detection result in the detection unit;
A storage unit for storing specific information;
A collation unit that collates information processed by the processing unit with the specific information;
Including
The writing tool includes at least one of a first reflecting portion having a different reflectance in a longitudinal direction of the writing tool and a second reflecting portion having a different reflectance in a rotation direction around an axis along the longitudinal direction. Have
The detection unit detects reflected light from at least one of the first reflection unit and the second reflection unit,
The processing unit is based on a detection result of the detection unit, and at least one of movement amount information of the first reflection unit in the longitudinal direction and rotation amount information of the second reflection unit in the rotation direction. A signature authentication system characterized by requesting. The first reflecting portion gradually changes in reflectance in the longitudinal direction of the writing instrument,
The signature authentication system according to claim 1, wherein a reflectance of the second reflection unit gradually changes in the rotation direction around an axis of the axis along the longitudinal direction.   The signature authentication system according to claim 1, wherein the processing unit obtains a movement trajectory of the writing instrument based on a detection result of reflectance at the first reflecting unit.