JP3262297B2 - Optical coordinate input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coordinate input device, and more particularly, to a stylus pen having a coordinate information reading device including an optical system and a light receiving section, and a passive digital device having a pattern including two-dimensional coordinate information. The present invention relates to an optical coordinate input device that is configured with a computerized tablet and can perform handwriting input on the surface of the tablet.

[0002]

2. Description of the Related Art Conventional optical coordinate input devices include an optical digitizer disclosed in JP-A-61-43328 (JP-B-2-18722), a stylus locator disclosed in JP-A-3-37707 and There is a data entry system.

[0003] In the former optical digitizer, when a figure drawn on paper is read and input, a transparent plate on which an M-sequence lattice pattern is drawn is placed on paper, and a two-dimensional CCD element or the like is used. A cursor having a built-in optical reading device is arranged on the transparent plate, and the cursor is moved on the transparent plate by tracing the figure and the position of each part of the figure is designated by the cursor. The coordinates of the designated position are obtained by reading a part with the optical reading device, whereby the figure can be read.

[0004] The latter stylus locator and data input system include a tablet and an optical stylus that is scanned on the tablet and optically reads coordinate values at arbitrary positions on an XY coordinate plane defined on the tablet surface. The tablet is a passive digitizing tablet, on the surface of which a light detectable pattern (tablet address cell) including a binary code indicating coordinate information on a two-dimensional coordinate plane is recorded. The light stylus has a built-in light source, an optical system, and a light-receiving element. When a position on the tablet surface is specified by the light stylus, a binary code is read by the tablet address cell and specified by the special computer with the light stylus. The coordinates of the position are determined.

[0005]

Problems to be Solved by the Invention
In the optical digitizer disclosed in No. 8, the position indicator has a cursor-type and code-added configuration, and further includes an illumination light source inside the cursor-type position indicator and irradiates the cursor using a plurality of optical filters. The frequency of light used for reflection is set to a predetermined value. Therefore, the structure is complicated and the manufacturing cost is high. Although the embodiment uses a lattice pattern in which one-dimensional M-sequences are orthogonalized, the number of cells of the light receiving element is required to be large, and the coordinate detection process becomes complicated and expensive.

[0006] In the stylus locator and data input system disclosed in JP-A-3-37707, the photodetectable pattern recorded on the surface of the passive digitizing tablet is formed by a plurality of discrete cells of the tablet address cell; In addition, in order to read a coordinate position using an optical stylus, it is necessary to include at least one tablet address cell in the field of view of the light receiving element. Therefore, a large number of cells are required, and the apparatus becomes expensive.

An object of the present invention is to provide an optical coordinate input device which has a passive digitizing tablet having a simple structure, can be manufactured at low cost, and is highly economical.

[0008]

According to the present invention, there is provided an optical coordinate input device comprising a matrix of digitally coded large and small dots having an arrangement of M planes including two-dimensional coordinate information.
And tablets Ttopatan is recorded on the surface, the read part of the dot pattern <br/> over emissions corresponding to the indicated position on the surface of the tablet with an optical device and the optical device to optically read A position indicator including a modulator that generates a signal related to a part of the dot pattern, an oscillator, and a signal generating unit including a transmission coil , and a signal related to the part of the dot pattern, and one of the signals obtained from the signal. Part of
Coordinate code based on the pattern image related to the dot pattern
Is calculated, and this coordinate code is indicated by the position indicator.
And coordinate information extracting means for extracting the two-dimensional coordinate information of the selected position .

In the above arrangement, preferably, the coordinate information extracting means includes a pattern image relating to a part of the dot pattern.
Output level of each pixel on the pixel array area based on
Obtain a large number corresponding to a large dot and
Means for obtaining a smaller number corresponding to the dot, and means for enlarging the image space regarding the number <br/> value, and means for smoothing the numerical applying a smoothing operator to the image space regarding numbers, smooth Means for creating a top table by selecting large numerical values from the numerical values included in the image space related to the converted numerical values, and means for generating a coordinate code using, for example, four numerical values included in the top table.

[0010] In the configuration described above, preferably, motor vibration <br/> Tsu DOO has a reception unit that receives a signal.

[0011] In the configuration described above, preferably, receiving portion comprises a demodulator. Further, the receiving unit includes a receiving coil provided around the surface of the tablet.

[0012]

According to the present invention, a tablet having a simple structure is formed by using a passive digitizing tablet having a pattern formed of fine, for example, large and small dots having the arrangement characteristic of the M plane recorded on the surface thereof. Coordinate input is performed by designating a position using an optical device having an operation of partially reading the pattern and an optical position indicator having a signal generating means for generating a signal including read pattern information. be able to. In this coordinate input, a coordinate code included in the partial pattern is extracted by the coordinate information extracting means based on information on the partial pattern read by the optical device. The processing for coordinate code extraction performed by the coordinate information extracting means is an arithmetic processing for uniquely calculating coordinates on the tablet surface. Thus, the coordinate code for obtaining the coordinate position of the position is extracted based on the partial pattern information corresponding to the position designated by the position indicator on the tablet surface, and the two-dimensional coordinates corresponding to the coordinate code are extracted. It is possible to get. In addition, a transmitting unit is provided in the position indicator, and by the modulation and resonance transmission operation, a part of the read pattern information is given to the receiving unit on the tablet side. In this transmission, a characteristic receiving antenna is used. Electromagnetic waves having relatively low frequency and low directivity can be used.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view showing the internal structure of the stylus pen. Inside the stylus pen, an optical device, a modulator, an oscillator, a transmission unit, and the like are provided as input means (pen-type position indicator) of the pen input computer. Here, the “optical device” includes a light guiding optical system and a light receiving element, and reads a pattern image for partially reading a pattern including two-dimensional coordinate information recorded by drawing or the like on the surface of a tablet described later. Means vessel.

The structure of the stylus pen 1 will be described. The stylus pen 1 has a transmission coil 3 in the tip of a pen housing 2. The transmission coil 3 is an inductance element of a resonance circuit described later, and has a transmission function. The transmission coil 3 has a ferrite core 4 in the inner space, and the transmission coil 3 is wound around the ferrite core 4. A hole is formed in the shaft portion of the ferrite core 4, and the core body 5 is arranged in this hole so as to be inserted therethrough. The core body 5 advances or retreats in the axial direction in the inserted state. The core 5 has a function of transmitting the pen pressure to the pen pressure detecting device 6 when the tip of the stylus pen 1 projects out of the pen tip and the tip of the stylus pen 1 contacts the surface of the position coordinate tablet. Therefore, the core 5 functions as a pen pressure transmitting means. The pen pressure detecting device 6 detects the transmitted pen pressure and gives a detection signal to the oscillator 8 on the circuit printed circuit board 7. The oscillator 8 includes a resonance circuit that uses the transmission coil 3 as an inductance element, and has a circuit configuration that changes, for example, the oscillation frequency of the resonance circuit when a detection signal is given from the writing pressure detection device 6. The circuit printed circuit board 7 is further provided with a light receiving element 9 such as a CCD area sensor, a modulator 10, and a side switch 11. The stylus pen 1 functions as a cordless stylus pen with the oscillator 8 and the transmission coil. The side switch 11 extends outside the pen housing 2. A power supply 12 such as a battery is disposed after the circuit printed circuit board 7 and supplies power to each circuit section on the circuit printed circuit board 7.

Next, the configuration of the optical device will be described. A light guide path housing 13 for forming a light guide path (light path) is formed integrally with the pen housing 2 on the upper front side of the pen housing 2. In the light guide path housing 13, a tendency prism 14 is provided at a window at the front end, a condenser lens 15 is provided at a central required position, and a reflector 16 is provided at the back. A light receiving element 9 having a light receiving surface (field of view) 17 is provided at a position above the circuit printed board 7 below the reflection plate 16. The light receiving surface 17 is formed by a large number of pixels arranged two-dimensionally. At the front end of the light guide path housing 13 at the tip of the stylus pen 1, a window for taking in external light (light from the outside) formed by the trend prism 14 is formed. External light entering from the pen tip through the window is guided in the longitudinal direction of the light guide path by the tendency prism 14, collected by the condenser lens 15, reflected by the reflector 16, and enters the light receiving surface 17 of the light receiving element 9. . The light received by the light receiving element 9 is output as an electric signal proportional to the light intensity based on the photoelectric conversion action of each pixel. The output signal of the light receiving element 9 is provided to the modulator 10. In the above configuration, external light is taken in. However, an illumination light source may be provided inside, and irradiation light may be given to the tablet surface to take in the reflected light.

In FIG. 1, reference numeral 18 denotes a tablet disposed in front of the tip of the stylus pen 1. Tablet 1
8 is a passive digitizing tablet which does not actively act on the stylus pen 1 itself. A predetermined pattern is recorded by drawing or the like on the surface of the tablet 18 facing the tip of the stylus pen 1. This pattern is a pattern having an arrangement of M planes, and is a dot pattern including two-dimensional (XY) coordinate information that determines an absolute position on the surface of the tablet 18. When the stylus pen 1 approaches the surface of the tablet 18, the light receiving surface 1 of the light receiving element 9 passes through a window (trend prism 14) at the tip thereof.
7, an image of a part of the pattern can be projected. A part of the pattern detected on the light receiving surface 17 of the light receiving element 9 represents a code related to a coordinate of a position specified by the stylus pen 1 on the tablet surface, and a two-dimensional position coordinate can be obtained by the coordinate code. Reference numeral 19 denotes a trajectory in which light rays coming from the surface of the tablet 18 are guided to the light receiving surface 17 of the light receiving element 9.

As shown in FIG. 2, the pattern image detected on the light receiving surface 17 which is the field of view of the light receiving element 9 is output as an electric signal by the photoelectric conversion of each pixel and supplied to the modulator 10. The modulator 10 changes the oscillation output (oscillation frequency, amplitude, etc.) set by the next stage oscillator 8 with the output signal. The output signal of the modulator 10 includes the input information (dot information) on the pattern image. Therefore, the output signal of the oscillator 8 is modulated based on the information on the pattern image detected by the light receiving element 9. Become. At the output of the oscillator 8, a signal relating to the pattern image detected by the light receiving element 9 is generated. In the above embodiment, the configuration for generating a signal in the case of a cordless styleless pen has been described.However, in the case of a styleless pen with a cord, an oscillator or a modulator is not required, and a signal transmitting unit of an arbitrary format is capable of transmitting a signal. Is a means for generating

The image reflected on the light receiving surface 17 of the light receiving element 9 is generally an image formed by visible light. However, by providing an infrared light pass filter in front of the light receiving surface 17, it is possible to use only infrared light. it can. According to the configuration using infrared rays, disturbance can be removed, and a pattern image can be obtained accurately.

Transmission coil 3 wound around ferrite core 4
Is used as an inductance element forming a resonance circuit as described above, and the detection signal of the pen pressure detecting device 6 is supplied to the modulator 10 and the power supply controller 21. Reference numeral 11 denotes a side switch, and a signal generated when the switch is turned on is a modulator 1.
0 and the power supply controller 21. Thus, the writing pressure information and the ON operation information are included in the oscillation signal via the modulator 10. Reference numeral 12 denotes a power supply. When the pen pressure detecting device 6 detects the pen pressure or the side switch 11 is turned on, a driving DC power is supplied from the power supply 12 to the modulator 10 and the oscillator 8 via the power supply controller 21 so that the modulator 10 The oscillator 8 becomes active and the modulator 10 is given operation information. An oscillation signal is output from an oscillator 8 including a resonance circuit including the transmission coil 3 and a capacitor (not shown). This oscillation signal generates a relatively low frequency electromagnetic wave in the surrounding space. The electromagnetic wave output from the transmission coil 3 to the surrounding space is modulated by a modulation signal output from the modulator 10 by amplitude modulation or the like, and information on the pattern image detected on the light receiving surface (field of view) 17 of the light receiving element 9. Contains. As described below,
According to the pattern drawn on the surface of the tablet 18, each part includes the coordinate information of the position corresponding to each part, so that the electromagnetic wave output from the transmission coil 3 includes the part specified by the stylus pen 1. Coordinate information is included.

FIG. 3 shows a configuration and a circuit configuration on the tablet 18 side. The tablet 18 has an upper flat surface 18a having a rectangular shape, a two-dimensional coordinate plane is defined on the upper surface 18a, and an arbitrary point on the surface 18a is designated by the stylus pen 1 to obtain coordinates of the designated position. ing.
A pattern is drawn on the surface 18a. FIG. 4 shows an enlarged part of the pattern. This pattern utilizes a two-dimensional sequence called an M plane. The M-plane is described in detail in "Coding Theory" published by Shokodo in 1973, co-authored by Hiroshi Miyagawa, Yoshihiro Iwadare and Hideki Imai. The pattern based on the arrangement of the M plane is, for example, a digitally coded dot pattern formed by fine small circles (dots) and large circles (dots). A square 24 shown by a broken line in FIG. 4 corresponds to the visual field of the light receiving element 9, that is, the area of the light receiving surface 17. In the example shown in FIG. 4, three large circles and one small circle are in the field of view of the light receiving element 9. The illustrated M-plane pattern has a characteristic that partial patterns composed of 2 × 2 circles do not overlap. Therefore, the coordinates of the position on the tablet surface where the partial pattern exists can be obtained based on the 2 × 2 partial pattern. The circle that draws the pattern is extremely small,
The resolution of the XY coordinates on the tablet surface is determined based on the size. In the illustrated example, the number of dots is reduced for convenience of explanation, but actually, for example, one dot is used.
If a resolution of 0.5 mm is to be obtained in a state where correction between dots is not performed on a coordinate reading surface of 2.5 cm square, 250 × 250 dots are required, and an arbitrary address is obtained. Needs to read 4 × 4 dots. The number of pixels of the light receiving element at this time is 32 × 32
The degree is appropriate, and a resolution of 0.1 mm can be obtained by performing an interpolation operation.

A receiving coil 25 is provided around the surface of the tablet 18. An appropriate position is designated on the surface of the tablet 18 with the stylus pen 1 and the side switch 11
Is turned on, the oscillator 8 performs an oscillating operation,
The light receiving surface 17 of the light receiving element 9 is controlled by the modulator 10 and the oscillator 8.
The output of the oscillator is modulated based on an image pattern (including a coordinate code) represented by a part of the pattern corresponding to the designated position shown in FIG. The electromagnetic wave 28 radiated from the transmitting coil 3 based on the oscillation action is received by the receiving coil 25. The electromagnetic wave received by the receiving coil 25 includes the image pattern, and as a result, includes the coordinate code. An output signal including the image pattern of the receiving coil 25 is input to the demodulator 26. The demodulator 26 is the receiving coil 2
The image pattern is extracted from the output signal of No. 5. The demodulator 26 also extracts pen pressure information and side switch information.
The signal representing the image pattern of the demodulator 26 is supplied to the coordinate information extracting means 27, where a coordinate code, that is, coordinate information, is extracted from the signal representing the image pattern. The position coordinates on the two-dimensional surface 18a of the tablet 18 can be uniquely determined based on the extracted coordinate codes. The coordinate code (coordinate information) extracted by the coordinate information extracting means 27 is supplied to the information processing device 29, and the above pen pressure information and side switch information extracted by the demodulator 26 are also supplied to the information processing device 29. You.

Next, with reference to FIGS. 5 to 11, a description will be given of a calculation method for extracting a coordinate code in the coordinate information extracting means 27 based on the pattern image detected on the light receiving surface 17 of the light receiving element 9. FIG. . The description will be made according to the flowchart of FIG.

In FIG. 5, it is assumed that the area shown by the broken line represents the light receiving surface 17 of the light receiving element 9. It is assumed that an image of a part of a pattern formed by a plurality of large circles and small circles is projected on the light receiving surface 17 indicated by a broken line in the illustrated state. A part of this pattern is used for convenience of explanation.
The inside and the outside are shown. Numerals are written in a broken-line rectangular area representing the light receiving surface 17 corresponding to the pattern image in the light receiving surface 17. The portion corresponding to the large circle is indicated by a relatively large value, and the portion corresponding to the small circle is indicated by a relatively small value. Each of the numerical values corresponds to one pixel, and the magnitude of the value is the level of the output signal corresponding to the detected image. As is clear from the description of the numerals in the broken-line rectangular area representing the light receiving surface 17, in the description of this embodiment, the pixel array of the light receiving surface 17 of the light receiving element 9 is formed of 9 × 9 pixels. The information (9 × 9) of the pattern image of the light receiving surface 17 shown in FIG.
The pixel information represented by the numerical values is sent to the coordinate information extracting means 27 through the modulator 10, the oscillator 8, the transmitting coil 3, the receiving coil 25, and the demodulator 26. The coordinate information extracting means 27 extracts a coordinate code based on the information of the pattern image according to the flowchart shown in FIG.

Under the above technical premise, step S1 shown in FIG. 11 is executed to read 9 × 9 pixel information and store the numerical value of each pixel in the buffer memory BUF (18 × 18). At this time, the storage location has increased four times,
The same numerical value is stored in four adjacent pixel array elements. Thus, the BUF (18 × 1) in which the numerical value is stored
FIG. 6 shows the storage state of 8). As is clear from FIG. 6, the pattern image (numerical image) of the light receiving surface 17 of the light receiving element 9 is magnified, for example, four times. Next, for example, using a suitable smoothing operator as shown in FIG.
Superimposition integration is performed on the stored contents of 8), and smoothing is performed (step S2). As a result, BUF (18 × 1
The storage state of the numerical value in 8) is as shown in FIG.
In the next step S3, B having the numerical value storage state of FIG.
In the UF (18 × 18), the element with the largest numerical value (top element) is searched, the address and the numerical value are written in the top table, and then the value of the element and its neighboring elements is set to 0. Then again find the element with the largest number and repeat the same. This operation is repeated until all elements become zero. FIG. 9 shows the data state of the top element written in the top table, and FIG. 10 shows the position (address) and numerical value of each top element written in the top table in BUF (18 × 1).
This is shown on the plane 8). In the top table shown in FIG. 9, the four top elements whose addresses are closest to the center of the light receiving surface 17 of the light receiving element 9 (the point which becomes (8.5, 8.5) in coordinates) are selected (step S4). This 4
The two top elements are shown in FIG. 10 by circled numbers. When the numerical values of the four elements are, for example, 40 or more, "1" is allocated, and when the numerical values of the four elements are 39 or less, for example, "0" is allocated. Generates a coordinate code. Thus, the coordinate code can be extracted.

Each step executed by the coordinate information extracting means described with reference to FIG. 11 is realized by a microcomputer as a function realizing means.

In the above embodiment, a coordinate input device having a pen-type position indicator has been described. However, the present invention can be applied to a cursor-type position indicator. A method of extracting a coordinate code from a part of a pattern having an arrangement of M planes is shown in FIG.
However, the present invention is not limited to the above method.

[0028]

As is apparent from the above description, according to the present invention, a tablet is formed by using an M-plane array pattern formed so as to include coordinate information, while a stylus pen is formed. Since the configuration is such that the pattern at the specified position is partially read and the two-dimensional coordinates of the commanded position are obtained based on the read pattern image, the configuration of the coordinate input device is simplified and the device can be manufactured at low cost. And economic efficiency can be improved. In addition, since signals are exchanged between the position indicator and the tablet using a transmitting unit in the position indicator and a receiving antenna arranged around the tablet surface, electromagnetic waves with relatively low frequency and weak directivity are used. It can be performed using:

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the internal structure of a stylus pen of an optical coordinate input device according to the present invention.

FIG. 2 is a circuit diagram showing a configuration of an electric circuit provided inside the stylus pen.

FIG. 3 is a circuit diagram showing an electrical configuration provided on the tablet side.

FIG. 4 is a diagram showing a part of a dot pattern showing a series of M planes.

FIG. 5 is a diagram showing a numerical image of a pattern image captured on a light receiving surface of a light receiving element.

FIG. 6 is a diagram in which a numerical image is magnified four times.

FIG. 7 is a diagram showing an example of a numerical pattern of a smoothing operator.

FIG. 8 is a numerical image obtained by smoothing the numerical image shown in FIG. 6 by a smoothing operator.

FIG. 9 is a diagram showing data contents of a top table.

FIG. 10 is a diagram showing a plane on which elements stored in a top table are arranged.

FIG. 11 is a flowchart illustrating a process of extracting a coordinate code from a read pattern image.

[Explanation of symbols]

 Reference Signs List 1 stylus pen 2 pen housing 3 transmission coil 4 ferrite core 6 writing pressure detector 8 oscillator 9 light receiving element 10 modulator 11 side switch 13 light guide path housing 14 trend prism 16 reflector 17 light receiving surface 18 tablet 25 receiving coil 26 demodulator 27 Coordinate information extraction means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G06F 3/03 310 G06F 3/03 380

Claims (5)

(57) [Claims] 1. Digitally coded large and small dots having an arrangement of M planes including two-dimensional coordinate information.
Wherein the dot pattern and tablets recorded on a surface, corresponding to the indicated position on the surface of the tablet
Optical device that optically reads part of the dot pattern
When to generate the signal for some of the dot path <br/> turn read by the optical device, a modulator and an oscillator transmission
A position indicator and a signal generating means comprising a coil, receiving a signal related to the dot pattern of the part, Pa according to the portion of the dot pattern obtained from the signal
A coordinate code is calculated based on the turn image, and the coordinate code is calculated.
The two-dimensional position of the position indicated by the position indicator
Optical coordinate input apparatus comprising: the coordinate information extraction means for extracting a target information. 2. The optical coordinate input device according to claim 1 , wherein said coordinate information extracting means comprises:
Pixels on the pixel array area based on the pattern image
Large number corresponding to large dot for output level of
Get the value and take the small number corresponding to the small dot.
Means for obtained, and means for enlarging the image space for the previous SL numeric, means for smoothing the numerical value by applying a smoothing operator to the image space regarding the figures included in the image space regarding the value obtained by smoothing optical coordinate input apparatus which comprises means for creating a top table by selecting large numbers from numbers, the means for generating the coordinate code by using a numerical value included in the top table. 3. The optical coordinate input device according to claim 1, wherein the position indicator transmits a signal relating to the partial dot pattern read by the optical device to the transmission coil.
Send Le, the tablet optical coordinate input apparatus characterized by having a reception unit that receives the signal. 4. The optical coordinate input apparatus according to claim 3 wherein, prior Symbol receiver optical coordinate input apparatus comprising: a demodulator. 5. The optical coordinate input apparatus according to claim 3 or 4, wherein the receiving unit is an optical coordinate input apparatus comprising: a receiving coil provided on the surface around the tablet.