JPH07200141A - Optical position detection device, optical coordinate input device, and optical position detecting method - Google Patents

Abstract

PURPOSE:To provide an optical position detection device which is simple in constitution, inexpensive, and compact and has a wide angle of field, and an optical coordinate input device which utilizes the optical position detection device. CONSTITUTION:The optical position detection device is equipped with one image pickup means 23, a pattern member 21 which has a specific pattern arranged in front of the image pickup means 23 on a path of light, and signal processing means 25, 26, 27, and 28 which extract information regarding the distance between a light emission source 3 and the image pickup means on the basis of a detection signal regarding the specific pattern projected in the image pickup area of the image pickup means. To extract the information regarding the distance, the distance between the pattern member and the image pickup area of the image pickup means needs to be known in advance. And, the distance to the light source which emits the light can be found by utilizing one image pickup means. The specific pattern is a pattern which has equal periodicity. The signal processing means perform statistical processing by utilizing the equal periodicity to find an enlargement rate determined by the shadow of the projected specific pattern, and this enlargement rate is utilized to extract information regarding the distance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical position detecting device, an optical coordinate input device, and an optical position detecting method, and in particular, a position indicator includes a light emitting section and uses light emitted from the light emitting section. An optical position detecting device, in which one photodetector detects the light, and the coordinate of the specified position is detected based on the distance to the light emitting part and the direction of the light from the light emitting part, and this position. The present invention relates to an optical coordinate input device configured using a detection device and an optical position detection method.

[0002]

2. Description of the Related Art As a device for detecting a position, a direction, etc., a PSD (semiconductor position detecting device: Position) has hitherto been used.
Sensitive Light Detector) is known. PSD
Is an optical sensor capable of detecting the position on the light receiving surface of the spot-like light irradiated on the light receiving surface. If this PSD is used, by combining with a point light source, a position detection device that detects the existing position of the point light source, a direction detection device that detects the arrival direction of a light ray from the point light source, and a distance between the point light source and the detection device main body It is possible to make a distance measuring device for measuring the electric field (transistor technology August 1990 issue "Production of distance detecting device using PSD").

Further, there is JP-A-5-19954 as a prior art document disclosing an apparatus for optically obtaining position information. In this device, a moving body provided with a light emitting element is moved on an operation table on which an XY coordinate plane is set, and an X-axis direction side center and a Y-axis direction side center side of the operation table are respectively moved by X-axis. Providing a light receiving part and a Y light receiving part,
The light from the light emitting element of the moving body is imaged at each light receiving unit by an optical lens, and the X coordinate value and the Y coordinate value of the moving body are obtained by using the image forming position information at each light receiving unit. ing.

[0004]

In order to detect the position and the like of a point light source using PSD, it is necessary to convert the light from the point light source into spot-like light and irradiate it onto the detection light receiving surface. However, an optical lens with good light-collecting performance is required, and the distance from the detection light-receiving surface to the point light source is limited.
There was a great limitation in use, and a correction process was necessary to obtain the required accuracy. In addition, in the literature (Japanese Patent Laid-Open No. 5-
Also in the optical coordinate information output device disclosed in Japanese Patent Laid-Open No. 199554), the information for obtaining the position of the moving body forms the light from the light emitting element in the spot shape by using the optical lens in the light receiving portion of the light receiving means. Therefore, similarly to the case of PSD, an optical lens having a high light-converging performance is required from the viewpoint of detectable position accuracy.

Therefore, in order to solve the problems of the above-mentioned conventional apparatus, the present inventor has previously proposed a light ray direction detecting section which does not use a lens, and two light ray direction detecting sections existing at further distant positions. Each of the light ray direction detection units is configured to detect the direction of the point light emitting unit provided on the position indicator and calculate the distance to the point light emitting unit based on these detection values. Proposed a position detecting device (Japanese Patent Application No. 5-87940, filed March 23, 1993). A linear image sensor is used as the light ray direction detection unit, and it is configured as a two-dimensional digitizer using the principle of triangulation. As another configuration, by using an area image sensor for the light beam direction detecting unit, the three-dimensional coordinates of the light source can be detected by the stereo method, and the three-dimensional digitizer is constructed.

Since the prior optical position detecting device proposed by the present inventor required at least two ray direction detectors, the number of light detecting portions was reduced, the signal processing circuit was simplified and the manufacturing cost was reduced. There is room for improvement in terms of reduction.

An object of the present invention is to enable calculation of the distance related to the light emitting portion directly using one photodetector, which can be constructed with a simple circuit structure, which is inexpensive and compact, and which has a wide viewing angle. An object is to provide a position detection device and an optical position detection method.

Another object of the present invention is to provide an inexpensive and compact optical coordinate input device by utilizing an optical position detecting device including a single photodetector.

[0009]

An optical position detecting device according to the present invention is provided with one image pickup means for detecting the intensity of light and a position in front of the image pickup means and on the optical path of the light. Information on the distance in the normal direction to the pixel array region between the light emitting source of the light and the image capturing unit based on the pattern member having the specific pattern and the detection signal relating to the specific pattern projected on the pixel array region of the image capturing unit. Is configured to include signal processing means for extracting In extracting the information on the distance, the distance between the pattern member and the pixel array area of the image pickup means needs to be known in advance. By using one image pickup means, it is possible to obtain the distance to the light source that emits light.

In the above construction, it is preferable that the image pickup means, the pattern means and the signal processing means are unitized as one optical position detecting device.

In the above structure, more preferably,
The signal processing means is composed of a pixel signal detection section that extracts a signal related to each pixel of the image pickup means and a processing section that obtains information related to a distance based on the signal related to each pixel. The processing unit is unitized as a device, the processing unit is provided on the side of a separately prepared host computer, and the pixel signal detection unit and the processing unit are connected by communication means.

In the above structure, the specific pattern is preferably a pattern having equal intervals. The equidistant property of the pattern means that, for example, the constituent parts of the pattern include equidistant parts of known intervals. The signal processing means is
Based on the known interval in the specific pattern, the magnification rate is obtained using the projected image of the specific pattern, and the information regarding the distance is extracted using this magnification rate.

The image pickup means includes a plurality of pixels, and each of the plurality of pixels outputs a detection signal corresponding to a portion relating to the equal interval property of the projected specific pattern. The signal processing unit can obtain the enlargement ratio by statistically processing the signals relating to each part of the pattern detected by each of the plurality of pixels, and thereby can measure the distance with high accuracy.

In addition to the information on the distance, the characteristic of the M series or the M plane included in the specific pattern is used to extract the information on the incident direction of the light arriving at the pixel array area of the image pickup means. .

The specific pattern is a two-dimensional pattern created by combining a one-dimensional linear pattern and a one-dimensional linear pattern orthogonal to the one-dimensional linear pattern, and the pixel array area of the image pickup means is a pixel of a two-dimensional lattice array. In the signal processing means, the pixel signals output from the pixels are integrated in each of the vertical direction and the horizontal direction so that the distance and direction information about one axis is separated and extracted. It can also be configured.

The optical coordinate input device according to the present invention comprises:
The position indicator is provided by using each of the above-mentioned optical position detecting devices, and further includes a position indicator having a light emitting portion that emits light or indirectly emits light, and the position on the input surface where the coordinate system is defined. When the side switch is operated while moving the indicator, for example, when the side switch is operated, the above-mentioned light emitting unit emits light, and the above-mentioned optical position detection device detects the light emitted by the light emitting unit and indicates with the position indicator. It is configured to obtain the distance and direction of the specified position and to obtain the coordinate data of the position. It can be configured as a two-dimensional digitizer by utilizing the distance and the ray direction. It is also possible to detect and use only the distance, and in this case, it is used as a one-dimensional digitizer.

In the above optical coordinate input device,
The display device may include a display device that displays information about input coordinates, and the coordinate input surface indicated by the position indicator may be the display surface of the display device.

The display device further includes a display device for displaying information on input coordinates, the position indicator is used by being attached to a finger of an operator, and the display device is configured to perform a display corresponding to the movement of the finger. You can also

In the optical position detecting method according to the present invention, the light of the point-like light emitting portion forms a shadow of a specific pattern including equidistant portions on the pixel array area of one image pickup means, and the pattern of the specific pattern is formed. The array direction and the pixel array direction of the image pickup means are coincident with each other, and the normal line to the pixel array area between the light emitting section and the image pickup means is obtained by obtaining the enlargement ratio based on the detection signal output from each pixel of the image pickup means. This is a method of extracting information about the distance in the direction.

In the above method, preferably, the enlargement ratio is statistically obtained based on each detection signal of a plurality of pixels of the image pickup means.

In the above method, the specific pattern includes characteristics of the M series or the M plane, and based on the characteristics of the M series or the M plane in addition to the information about the distance, the light arriving in the pixel array area of the image pickup means is detected. Information on the incident direction is extracted.

In the above method, information about distance,
And the coordinates of the point light emitting portion are calculated based on the information on the incident direction of light.

[0023]

According to the present invention, the position indicator is provided with a point light source (light emitting portion), the point light source is caused to emit light, and the intensity of the emitted light is a CCD linear image sensor (an example of an image pickup means). ) Is configured to detect. At this time, a pattern member having a known distance from the sensor light receiving region is arranged between the point light source and the CCD linear image sensor, and the pattern member has an equal interval and M series or M plane characteristics. Pattern is prepared. When the light from the point light source is applied to the pixel array area of the CCD linear image sensor, the pattern is projected on the pixel array area. As a result, each pixel of the CCD linear image sensor detects the pattern projection image and outputs a signal. Using the output signal of this CCD linear image sensor, the magnification rate of the projected pattern is obtained by performing statistical processing on the basis of the portion relating to the equidistant property,
Information on the distance is obtained by a predetermined calculation formula using this magnification. Further, the arrival direction of the light emitted from the point light source can be detected based on a predetermined arithmetic expression by utilizing the characteristics of the M series or the M plane included in the specific pattern of the pattern member. Further, an optical coordinate input device having a simple structure by using an optical position detecting device including one photodetector as described above, which can detect the distance and direction of a point light source, is provided. Can be made.

[0024]

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

FIG. 1 shows a first embodiment of the present invention and is a perspective view showing a system configuration of an optical coordinate input device. In FIG. 1, reference numeral 1 is a CRT display device, and a rectangular display screen 1a is formed on the upper surface of the CRT display device 1. The type of the display device is not limited to the CRT, and may be a liquid crystal display device, for example. The display screen 1a of the CRT display device 1 functions as an output surface for displaying input contents and other necessary information, and is designed to be an input surface of the optical coordinate input device. On the display screen 1a as the input surface, for example, a pen-type position indicator 2 is moved by the operation of the operator. As shown in FIG. 2, the pen-type position indicator 2 has a point light source 3 (hereinafter referred to as a point light source) at its tip and is configured as an optical position indicator. The existing position of the point light source 3 on the input surface is the position designated by the position indicator 2. The light source 3 has a function as a portion that emits point light,
The light may be emitted from itself, or may be indirectly emitted by being given light from another.

In the above description, the input surface of the optical coordinate input device does not have to be integrated with the display surface of the display device, and the input surface and the display surface can be configured separately.

At the upper corner of the rectangular display screen 1a, a photodetector 4 constituting an optical position detecting device is arranged. The photodetector 4 is an optical position detector, and includes one image pickup means (for example, CCD linear image sensor) and one light receiving element, as described later. The number of photodetectors arranged near the display screen 1a and receiving the light emitted from the point light source 3 of the pen-type position indicator 2 is only one. The optical position detecting device of the present embodiment can determine at least the distance to the position indicated by the pen-type position indicator 2 by using only one photodetector 4. Further, the direction of light that reaches the image pickup area (or the pixel array area) of the image pickup means from the point light source 3 can also be obtained. Furthermore, the optical position indicator 2
The coordinates of the pointed position can be calculated based on the distance and the light arrival direction obtained with respect to the pointed position by the point light source 3. Regarding the principle of obtaining the distance to the indicated position and the arrival direction of light by using only one photodetector 4,
It will be described later.

The optical coordinate input device according to the present invention comprises an optical position detecting device (or an optical coordinate detecting device, more specifically shown in FIG. 3) including the photodetector 4, and the point light source 3 described above. And a pen-type position indicator 2 (shown in FIG. 2). The optical position detection device receives the light emitted from the point light source 3 of the position indicator 2 and calculates the coordinate information regarding the existing position of the point light source 3 based on the light.

The output signal of the optical position detector provided in the CRT display device 1 is supplied to the arithmetic / control device 6 through the RS232C cable 5. The arithmetic / control device 6 is composed of, for example, a personal computer. The arithmetic / control device 6 calculates the distance data related to the position indicated by the optical position indicator 2 and the data regarding the light arrival direction based on the data generated by the detection signal of the photodetector 4. The obtained data is CR via the CRT cable 7.
The information of the designated position is displayed on the display screen 1a of the T display device 1.

FIG. 2 shows the internal structure of the optical pen type position indicator 2. The structure of the position indicator 2 and the circuit configuration of the built-in electric circuit section will be described with reference to FIG. The pen-type position indicator 2 is a position indicator made of a cordless type using light. Reference numeral 10 denotes a pen housing, and a pen tip portion 12 rotatably provided around a fulcrum 11 is attached to a tip portion of the pen housing 10. A writing pressure detector 13 contacts the input surface with the pen tip portion 12 to indicate an arbitrary position, and the writing pressure detector 13 detects the contact pressure. The writing pressure detector 13 is a variable capacitance capacitor whose capacitance changes by pressing, and is made of a dielectric material. The point light source 3 described above is provided at the end of the pen tip portion 12, and the pen housing 10 includes an electric circuit portion including an oscillator 14 and a driver circuit 15 therein, and a battery 16.
Further, an exposed side switch 17 is provided outside. The point light source 3 is the tip of the optical fiber 18 in this embodiment. When the operator operates the side switch 17 to turn it on, electric power is supplied from the electric circuit portion to the light emitting element 19 such as a light emitting diode, and the light emitting element 1
9 emits light. The light emitted from the light emitting element 19 is reflected by the lens 20.
The light is emitted from the point light source 3 to the outside through the optical system such as the above and the optical fiber 18. The operation of the side switch 17 means that the position indicator 2 indicates the position by emitting light from the point light source 3.

The oscillation frequency output from the oscillator 14 of the electric circuit section in the position indicator 2 is modulated. The light emission action of the point light source 3 is performed by using the modulated oscillation output. The writing pressure information detected by the writing pressure detector 13 and the information given by the side switch 17 are sent to the photodetector 4. This is because.

FIG. 3 shows an example of the circuit configuration of an optical position detector including the photodetector 4. A pattern plate 21 is arranged on the front surface of the photodetector 4. As will be described later, on the pattern plate 21, for example, a pattern formed by a plurality of lines arranged at equal intervals is drawn. The spacing of the lines in the pattern is known. Inside the photodetector 4, the light receiving element 22 and the CCD linear image sensor 2 are provided.
3 are arranged side by side, and a filter 24 is arranged in front of the light receiving element 22 and the CCD linear image sensor 23. The filter 24 is the point light source 3 of the position indicator 2.
It has the effect of passing only the light of the wavelength emitted from. The light emitting element 19 that emits infrared light is used, and the filter 24 is an infrared light transmitting filter, whereby background light other than the point light source 3 can be removed. The light receiving element 22 is a means for reading an operation signal included in the light from the point light source 3, and the CCD linear image sensor 2
Reference numeral 3 denotes a one-dimensional sensor, which is a means for inputting an image of a pattern projected on the imaging region (or light receiving region) thereof. The one-dimensional sensor means that many pixels are linearly arranged. Microscopically, since the light receiving surface of each pixel has a surface shape, the surface on which the pixels are arranged is called an imaging surface. In other words, the imaging area is a pixel array area. The pixel array direction of the image pickup surface and the pattern isolation direction (pattern array direction) of the above-described equidistant pattern are provided so as to be parallel (parallel to each other).

The output signal of the light receiving element 22 is input to the frequency counter 25, and the frequency counter 25 sends a signal proportional to the frequency of the output signal to the microcomputer 26. The analog signal relating to the pattern output from the CCD linear image sensor 23 is converted into a digital signal at a predetermined sampling timing by the A / D converter 27 and then supplied to the microcomputer 26. The microcomputer 26, as described later,
The barycentric position for determining the position of the line is calculated based on the signal relating to the projected position of the line of the pattern detected at each pixel. The data of the projected position of the line obtained at each pixel is RS
It is supplied to the arithmetic and control unit 6 through the 232C interface 28 and the RS232C cable 5.
The arithmetic / control device 6 is a CCD linear image sensor 23.
Of the pattern plate 2 by performing statistical processing using the position data regarding the pattern obtained in each of the plurality of pixels of
The magnifying power of the CCD linear image sensor 23 of the pattern 1 is obtained, and the magnifying power is used to calculate the distance to the point designated by the position indicator 2.

Next, the principle of obtaining the distance to the point light source 3 of the position indicator 2 and the incident angle of light using one photodetector 4 will be described with reference to FIGS. 4 is a diagram showing a geometrical relationship for obtaining a distance, FIG. 5 is a diagram showing an example of a pattern, FIG. 6 is a diagram showing a part of an output waveform of a CCD linear image sensor, and FIG. 7 is a pattern in a detection signal. FIG. 8 is a diagram for explaining how to determine the center position (line position) of the projection unit, and FIG. 8 is a diagram showing a relationship for obtaining the enlargement ratio and the incident angle of light.

Here, the distance to the point light source means the distance in the normal direction of the image pickup surface, that is, the position P of the point light source 3 when the center of the image pickup surface is the point O and the normal line of the point O is the Z axis. Z
The coordinates themselves. The X axis is the origin of the point O on the coordinate axis taken in the direction in which the pixels of the CCD linear image sensor are arranged, and the Y axis is the origin of the point O on the coordinate axis orthogonal to the pixel arrangement direction of the CCD linear image sensor and the Z axis. . In the case where the position detecting device of the present invention constitutes a two-dimensional digitizer, the incident angle of light means ∠QOZ when the foot of the perpendicular line drawn from the point P to the ZX plane is the point Q,
In the case where the position detecting device of the present invention constitutes a three-dimensional digitizer, when the foot of the perpendicular line drawn from the point P to the YZ plane is the point R, it means a set of ∠QOZ and ∠ROZ. In the case of a three-dimensional digitizer, the two array directions of the grid-like pixels forming the CCD area image sensor are the X axis and the Y axis, respectively. The origin is the intersection of diagonal lines when the CCD linear image sensor has a square shape.

The distance from the photodetector 4 to the point light source 3 is calculated based on the pattern image of the pattern plate 21 projected on the image pickup surface of the CCD linear image sensor 23.
Strictly speaking, the distance from the image pickup surface of the CCD linear image sensor 23 to a line passing through the point light source 3 of the position indicator 2 and parallel to the image pickup surface, that is, the Z coordinate is obtained.

In FIG. 4, reference numeral 30 denotes the point light source 3 of the optical pen type position indicator 2, reference numeral 21 denotes a pattern plate, and 23.
Is a CCD linear image sensor. Reference numeral 31 is a line that passes through the position 30 indicating the point light source 3 and is parallel to the imaging surface of the CCD linear image sensor 23. The alternate long and short dash line 32
Is a pattern plate 21 and a CCD linear image sensor 2
3 is a common center line, and a broken line 33 indicates a traveling state of light incident on the CCD linear image sensor 23.
The light 33 emitted from the point light source 3 passes through the pattern plate 21 and enters the imaging surface of the CCD linear image sensor 23. The angle between the Z axis and the above-mentioned ∠QOZ, in other words, the line segment QO obtained by projecting the line segment PO on the ZX plane is θ. At this time, a part of the pattern drawn on the pattern plate 21 is projected on the imaging surface of the CCD linear image sensor 23. In FIG. 4, dimensions L1, L2, L3 and L4 are defined as shown. L1 is the horizontal direction of the pattern projection area on the imaging surface of the CCD linear image sensor 23 (pixel array direction)
L2, the light 33 from the point light source 3 is the pattern plate 21.
The horizontal length of the area that is transmitted by L3 is the pattern plate 21.
Between the CCD linear image sensor 23 and the CCD, L4
Is the distance between the line 31 and the imaging surface of the CCD linear image sensor 23. Regarding the above L1 to L4, the relationship of L4: L1 = (L4-L3): L2 is established based on the geometrical relationship. Here, L1 / L2 corresponds to the enlargement ratio of the pattern, and is therefore set to m. As a result, L4 is {m / (m-
1)} × L3. According to this equation, the distance L3 is known, so if the magnification ratio m is calculated,
The distance L4, that is, the Z coordinate of the point P can be calculated. As will be described later, the pattern provided on the pattern plate 21 is preferably an equidistant pattern, and the isolation direction is arranged so as to coincide with the pixel array direction of the CCD linear image sensor 23. And more preferably, the pattern is composed of a pattern of line segments drawn perpendicularly to the isolation direction. Therefore, even if the position of the point P is slightly floating, that is, even if the size of the line segment PQ has a certain size, the same pattern as that when the point P is on the XZ plane is created in the CCD linear image sensor 23. become.

As an example, when using a CCD linear image sensor having 2048 pixels and an inter-pixel pitch of 14 μm, if L3 is 35 mm and L2 is 20 mm, L1 is 23 mm and L4 is 268. .33 mm, and when L1 is 23.014 mm, L4 is 267.25 mm
Therefore, a distance resolution of about 1 mm can be obtained for one pixel.

The magnifying power m is calculated as follows. First, an example of the pattern used is shown in FIG. A part 40 of the pattern shown on the pattern plate 21 is enlarged and shown as 41 on the imaging surface of the CCD linear image sensor 23. The pattern is first expressed by lines arranged at equal intervals. Next, in the middle of the lines, there is a line at a position corresponding to the digital code “1”, and the digital code “0” is present. A blank portion is formed at a position corresponding to. Here, the sequence of "1" and "0" is the code sequence of the M sequence. Here, the M sequence is a code sequence that is often used in the field of communication technology, and for example, in the case of a 6-bit M sequence, the position of any consecutive 6-digit code is extracted. Is a code sequence that is uniquely determined to be some position on the pattern. On the imaging surface of the CCD linear image sensor 23, each pixel detects the intensity of light based on the part 40 of the pattern. As a result, the waveform of the signal output from the CCD linear image sensor 23 is as shown in FIG. In FIG. 6, the horizontal axis represents the position of each pixel of the CCD linear image sensor 23, and the vertical axis represents the output level (light reception intensity signal) of each pixel. In the output level, a low signal level is a portion where a line portion of the pattern is projected, and a high signal portion is a portion where the other portion is projected. CCD linear image sensor 23
In each pixel, the portion where the line portion of the pattern is projected is the shadow portion. In order to accurately find the position of the line shadow of the pattern, it is necessary to find the center position of the shadow. Therefore, for example, as shown in FIG. 7, a threshold level 42 is set in the output waveform of each pixel of the CCD linear image sensor 23, a barycentric position 43 is obtained at a signal level portion lower than that, and this barycentric position is determined in the pattern. Determined as the location of the line. In addition to the general method of obtaining the center of gravity position for obtaining the center position of the line shadow position,
There is also a method of obtaining the position of a line segment in which the hatched area in FIG. The position where the line shadow exists is treated as the center position of the shadow. In this way, the positions x0, x1 to x5, ..., X-1 to x-7, ... Of the line shadows of the pattern detected by each of a large number of pixels are determined based on the pattern projection portion of the CCD linear image sensor 23. Desired.
By obtaining the projected position of the pattern as the position of the center of gravity as described above, it is inevitably possible to perform interpolation of about a few fractions.
The accuracy of distance measurement is improved. That is, the resolution of the X coordinate can be made finer than the pixel pitch of the CCD linear image sensor.

The pattern provided on the pattern member 21 has equal intervals depending on the intervals of the lines, and the presence or absence of lines between the lines arranged at equal intervals, that is, depending on the above "1" and "0". It also has the characteristics of the M series.

The magnifying power m is obtained from the position data of the pattern detected based on the pattern projection on the CCD linear image sensor 23. FIG. 8 is a graph for showing an example of obtaining the enlargement ratio m. The horizontal axis shows the position of the pattern projected on the imaging surface of the CCD linear image sensor 23, and the vertical axis shows the relative position of the pattern. . Here, the relative position means that the pattern projected on the central portion of the CCD linear image sensor 23 is the point light source 3 as described above.
Is a concept that is provided because it is a part of the pattern plate 21 that can dynamically change when the position of the pattern plate 21 changes. The pitch is determined as one unit. Note that this graph is drawn only for the purpose of facilitating visual understanding of the calculation of the enlargement ratio and the like, and the CCD linear image sensor 23 and the pattern plate 21 are arranged in a spatially right-angled relationship. It does not mean that it will be done. As described above, the CCD linear image sensor 23 and the pattern plate 2
1 is arranged in parallel (so that the pixel array direction of the CCD linear image sensor 23 and the pattern separation direction of the pattern plate 21 coincide with each other).

In the graph of FIG. 8, the origin 0 on the horizontal axis is C
This is the position of the center point of the CD linear image sensor 23.
The horizontal axis corresponds to the X axis described above. CC
A part of the equally-spaced pattern of the pattern plate 21 is projected around the origin O, which is the center point of the D linear image sensor 23. Among them, the one closest to the origin O in the negative region of the X axis, that is, x0 The position of the line shadow of the pattern is the position where the relative position of the pattern is 0. The position determination of x0 can be intuitively understood by a person who sees FIG. 6, but in the case of the equidistant pattern including the M-series code sequences used in the present invention, the position determination can be performed by a computer process. When attempting to do so, preprocessing is required to extract equidistant patterns from the pattern. The processing is performed as follows, for example.

When the M-sequence is 6 bits, the longest "1" code is 6 in the pattern. This is because if there are seven or more, there will be two or more sequences in which six 1's continue, and the position cannot be uniquely determined. Therefore, considering the line shadows of the equally-spaced pattern provided on both sides of each line shadow forming the line, 13 line shadows may be lined up at intervals of half the pitch of the equal intervals. To put it the other way around, if fourteen continuous line shadows are detected, at least one of them is a part where the line shadows are isolated at an equal pitch of the equidistant pattern, in other words, It can be said that it is a portion forming “0” in the M-sequence code sequence.

Therefore, the computer starts with a sequence of 14
The position of each line shadow is detected, and the isolation distance between them is calculated. These 14 are in the case of a 6-bit M series, and are 16 in 7 bits and 18 in 8 bits.
Next, it is confirmed that there are almost two types of the obtained separation distances, and that the large separation distance is about twice as large as the small separation distance, and it is acquired as the pitch of the equidistant pattern. Further, returning to the line shadows on both ends of the obtained pitch, the positions of the line shadows existing at that pitch on the plus side and the minus side are sequentially acquired from the line shadow. Of these, x0 is the one closest to the origin on the negative side of the X axis.

The pitch of the equally-spaced pattern used here is used for the convenience of obtaining the line shadows of the equally-spaced pattern, and is necessarily the same as the pitch of the pattern on the pattern member 21. Not a thing.

Now, the line shadows showing the equally-spaced patterns thus extracted, that is, x1, x2, x shown in FIG.
Relative position of pattern 1, 2, 3, 4 with respect to 4, 5
Are added respectively and plotted. Also, x- referred to in FIG.
Position of pattern relative to 2, x-3, x-5, x-7
1, -2, -3, -4 are added and plotted. Relative position 0 is given to x0 and plotted.

It should be noted that 2.5, − is also applied to the line shadow showing the pattern of M series “1” which is not the line shadow of the equally spaced pattern.
It is also possible to give a relative position of half the pitch such as 0.5, and plot it, and FIG. 8 shows an example thereof.

On the abscissa of the graph shown in FIG. 8, the position of the line shadow calculated as the position of the center of gravity is plotted, and when the points are taken in relation to the position of the corresponding ordinate, the least squares method is applied. Then, the straight line 44 can be determined. Since the inclination of the straight line 44 thus obtained is given as 1 / m using the enlargement factor m, the enlargement factor m can be obtained by obtaining the inclination. By such statistical processing and the above-described calculation of the position of the center of gravity, at least sufficient 1
A degree of interpolation can be performed. In the example described above, the distance L4 can be obtained with an accuracy of at least about 0.1 mm.
However, in the above description, the points are plotted and the slope of the straight line is obtained by using FIG. 8 for the sake of convenience. In terms of computer processing, the least squares method is applied to enlarge in accordance with a corresponding predetermined procedure. Find the rate m.

As described above, the calculation of the position of the center of gravity for obtaining the position of the projection portion of the pattern line is performed by the microcomputer 26.
The calculation of the enlargement ratio m and the distance L4 is performed by the calculation / control device 6. However, the configuration is not limited to this. For example, either the microcomputer 26 or the arithmetic and control unit 6 may be configured to perform all calculations. Further, in order to perform statistical processing on the calculation of the enlargement ratio m and improve its accuracy, it is necessary to use a pattern having equal intervals, but if the accuracy is not required to be high, the interval is simply known. The distance can be obtained only by using a certain pattern.

Since the data of the distance L4 obtained as described above is related to the position designated by the position indicator 2, that is, the Z coordinate itself described above, the coordinate of the designated position is utilized by using this distance data. It will be possible to obtain.
Information regarding the obtained coordinate data is transferred from the arithmetic / control device 6 side to the CRT display device 1 side through the CRT cable 7, and necessary information is displayed on the display screen 1a.

According to the above-described embodiment, since the pattern member is used without using the optical system such as the lens, the structure is simplified, the cost can be reduced, and the wide viewing angle can be obtained. You can In the case of a lens or a single slit, the viewing angle strongly depends on the size L1 of the image pickup surface, but in the case of this embodiment, the viewing angle strongly depends on the size of the pattern and does not depend so much on L1, so that a wide viewing angle is secured. It's easy. In addition, since the distance to the indicated position can be obtained by using a single photodetector, the structure can be simplified and the manufacturing cost can be reduced in that the number of photodetectors used can be reduced. it can. In terms of improving the measurement accuracy, the detection rate of a plurality of pixels included in the CCD linear image sensor 23 is used to obtain the enlargement ratio and the distance by statistical processing. Therefore, the accuracy can be improved. it can. In the current technical situation, a high-resolution CCD linear image sensor is relatively inexpensively available as an image sensor. Therefore, a configuration using two ray direction detectors, that is, two low-resolution CCDs is used. It is more economical to use one high-resolution CCD linear image sensor than to use a linear image sensor.

The incident angle of the light 33, that is, the angle θ formed by the center line of the light 33 and the image pickup surface of the CCD linear image sensor 23 is given by tan θ = D / L3. Here, D is the X coordinate of the point where the line connecting the point light source 3 and the center O of the CCD linear image sensor 23 intersects the pattern plate 21, as shown in FIG. The X axis is the same as that described above. The incident angle of the light from the point light source 3 can be obtained by calculating the above D by giving the above pattern a characteristic of M series. The information on the incident angle of light (direction of arrival of light) is used when calculating coordinate data. The X coordinate of the point light source P is X = Z · tan
This is because it can be obtained as θ. The incident angle θ of light is obtained as follows. First, the information on the barycentric position of each line shadow shown in FIG. 6 and the information on the equidistant line shadows obtained by the extraction process of the equidistant pattern executed as the preprocessing of the above-described enlargement factor m calculation process are acquired. Then, in the middle of line shadows at equal intervals, if there is a line shadow, it is set to "1", and if there is no line shadow, "0" is set, and the number of bits required before and after the center of the CCD linear image sensor (for example, 6 bits) is taken to obtain a digital code. obtain. Since this is a partial code representing the position of the M series, it is converted into the corresponding discrete coordinates N by table conversion. Here, the discrete value coordinate N is a coordinate that is uniquely determined for each row of a predetermined number of consecutive bits, for example, 6 bits, according to the property of the M sequence. Pattern board 2
Since the coordinates are discrete values according to the pitch of the pattern drawn in 1, the coordinates are discrete. On the other hand, finer coordinates are needed to determine D. When considering the interpolated value, that is, the value (D−N), it can be seen that this corresponds exactly to the intercept d of the straight line obtained in FIG. Therefore, the relationship of D = N + d is established. As a result, the incident angle is tan θ = (N + d) / L
Required by 3. Since the intercept d is obtained by the least square method, the incident angle of light can be obtained with extremely high accuracy.

In the above embodiment, the Z coordinate of the position P of the point light source 3 can be calculated based on the calculation of the enlargement ratio m.
Further, the X coordinate of the position P of the point light source 3 is X = Z by calculating the intercept d and converting the table of the M series digital code.
・ It was possible to obtain it as tan θ. This is XZ
Realizing a two-dimensional digitizer that detects and inputs the position that changes momentarily when the point light source 3 moves on or near a plane using one CCD linear image sensor (that is, one-dimensional image sensor) Means that Extending the principle of the above-mentioned two-dimensional digitizer to a three-dimensional digitizer is to set the Y axis as described above, change the CCD linear image sensor to a CCD area image sensor, and change the pattern plate 21 only in the X axis direction. Alternatively, it can be achieved by changing to the one having the same property in the Y-axis direction.

FIG. 9 shows a second embodiment of the present invention. This embodiment realizes a three-dimensional digitizer by utilizing a CCD area image sensor, and at the same time, shows the motion of a real person and the display on the screen of the display device. It is configured to interact with an entity. Reference numeral 51 is a photodetector, a pattern plate 52 is attached to the front portion thereof, and a CCD area image sensor 53 is arranged inside. Although the light receiving element shown in FIG. 3 and other signal processing circuit sections are also provided as necessary, their illustration is omitted. Photo detector 5
The output signal from 1 is supplied to the arithmetic and control unit 6 through the RS232C cable 5. On the other hand, regarding the point light source, instead of the structure of the optical pen type position indicator, for example, the point light source 55,
56 is attached. The point light sources 55 and 56 are light emitting diodes. The point light sources 55 and 56 are configured such that power for light emission is supplied from a power source 58 via a switch 57. The switching operation of the switch 57 is performed by the arithmetic / control unit 6
From the switch control cable 59. When electric power is supplied from the power source 58 to the point light sources 55 and 56 through the switch 57 to emit light, the point light source 5
The light emitted from 5, 56 is detected by the photodetector 51, and the coordinates in the three-dimensional space can be obtained based on the distance detection principle described above.

A CRT display device 60 has a display screen 60a on which a sheet 61, for example, and a hand 62 of a person trying to pull the sheet 61 downward are displayed. Such display objects are
This is performed based on the information processing function and the display function of the control device 6. Then, the hand 62 in the display screen and the actual hand 54 are configured to have an interlocking relationship. That is, the position and movement of the hand 62 on the display screen are
Interlocks with the actual hand 54. This is because the coordinates of the point light sources 55 and 56 attached to the actual hand 54 are detected by the photodetector 51, and their coordinates are obtained, and the obtained coordinate data is converted into display data on the display screen 60a. I'm trying to display it. Thus, by interlocking the actual hand 54 with the hand 62 on the display screen, it is possible to perform an operation of pulling the sheet 61 virtually displayed on the display screen with the hand 62 on the screen. .

FIG. 10 shows an example of a pattern projected on the CCD area image sensor 53 used in the above embodiment. This pattern is an example in which the pattern of the above-described first embodiment is formed in each of two orthogonal axial directions in a square area. "1" and "0" of the M series are expressed by the presence / absence of a line in the middle of the lines at equal intervals. CCD
The area image sensor 53 obtains image data as shown in FIG. 11 by projecting the pattern shown in FIG. 10, and integrates the pixel signal values in each of the x-direction and the y-direction, and The information can be removed and converted into the same signal as in the first embodiment. Further, by this processing, the signals relating to the respective directions are integrated, so that the signal-to-noise ratio (so-called S / N ratio) can be improved and weaker light can be detected. By performing the same processing as that of the first embodiment on the above-mentioned converted signal, distance data on the two-dimensional coordinate plane, and eventually coordinate data, are calculated. FIG. 12 shows another example of the pattern. This pattern is a two-dimensional series pattern called an M plane as shown in A of FIG. 12, and is formed by minute small circles (dots) and large circles (dots), and the two-dimensional position from the two-dimensional partial code. Is a digitally encoded dot pattern that can be uniquely defined. For example, vertical 3
A set of 3 bits per bit, that is, a 9-bit arrangement determines a unique position (discrete coordinates representing a set of XY coordinates on the pattern according to the coordinate axis described above) within the entire pattern. This pattern has a numerical meaning as shown in B of FIG. Further, the positions of the grid points corresponding to the positions of the dots become the portions having the equal intervals. M
Regarding the plane, written by Hiroshi Miyagawa, Yoshihiro Iwadari and Hideki Imai, 1.
He was familiar with "code theory" published by Shokodo in 973.

In the above-described embodiment, the center of gravity of each dot projected on the image pickup surface is obtained, and the three-dimensional coordinates of the light emitting source are obtained by obtaining the enlargement ratio of the interval with respect to the pattern and the two-dimensional displacement value. More specifically, the discrete coordinates N described above are obtained as a set of (Nx, Ny) by table conversion from the digital code of the M plane, but regarding the calculation of (dx, dy) obtained as an interpolation value, After the process of calculating the two-dimensional barycentric position of each dot, the process of obtaining dx and dy in each of the X direction and the Y direction is performed. Regarding the enlargement ratio m,
Since the enlargement factors mx and my in the X-axis direction and the enlargement ratios in the Y-axis direction can be calculated, processing such as using the arithmetic mean or geometric mean of the two as m is performed. The distance of the point light source is obtained from the enlargement ratio, and the XY coordinates at the intersection of the ray direction and the pattern plate are obtained based on the code of the M plane and the information of the two intercepts, thereby determining the three-dimensional coordinates of the light source position.

Next, another embodiment of the signal processing circuit for the detection signal of the CCD linear image sensor 23 will be described with reference to FIG. In this embodiment, a comparator having a reference voltage set, an edge detector, and a serial interface are used. As shown in FIG. 13, the output value of the CCD linear image sensor 23 is first compared with the reference voltage VREF by the comparator 71, binarized depending on whether it is larger or smaller than that, and then the binarized value. Information regarding the rising and falling edges of the pixel, that is, regarding which pixel number rises from 0 to 1 and which pixel number falls from 1 to 0 in the arrangement of the binarized information in the order of pixel numbers. The information is detected by the edge detection unit 72, and the result is sent to a higher-level device such as a personal computer (the above-described arithmetic / control device 6) through, for example, the serial interface 73 (RS232C or the like). Here, the pixel number is, for example, in the case of a CCD linear image sensor having 2048 pixels, information about what number out of the 2048 pixels, that is, the coordinates on the CCD linear image sensor 23. It is something that is directly linked to the concept (that is associated with it). On the side of the arithmetic / control unit 6 which is a so-called host computer, processing such as calculation of enlargement ratio, calculation of direction, calculation of coordinates and the like will be executed. A program therefor is added to the arithmetic / control unit 6 by incorporating a device driver or a program called driver software. In FIG. 13, reference numeral 74 indicates a device driver. In addition, inside the arithmetic and control unit 6, an operating system 75, application software 7
6. The interface 77 is built in as a general component. Since the processing speed and processing capacity of CPUs used in general arithmetic and control units have been remarkably developed in recent years, other application software, etc. may be used even if processing such as enlargement ratio, direction, and coordinate calculation is performed on the host computer side. It does not seem to affect the execution of. The processing content executed by the device driver 74 is the same as the above-described processing content such as the calculation of the enlargement ratio, the calculation of the direction, and the calculation of the coordinates.
The frequency counter 25 is provided in FIG. 13 in order to detect the continuous change amount of the switch and send it to the host computer side.

[0059]

As is apparent from the above description, the present invention has the following effects.

It is possible to detect the distance of the light source and the direction of the light ray using one photodetector, and further, it is possible to detect the two-dimensional coordinates and the three-dimensional coordinates.
Since the dimensional coordinates can be detected, the structure is simplified, and an economical and compact optical position detecting device and optical coordinate input device can be realized.

Since a large pattern can be used as compared with the image pickup surface of the image pickup means without using an optical system such as a lens, a wide viewing angle can be secured.

By utilizing a specific pattern having the property of equal intervals, a plurality of positions of each part of the pattern are detected based on output signals of a plurality of pixels provided in the image pickup means, and statistical processing is performed. Thereby, high detection accuracy can be achieved.

In the optical coordinate input device, the direction of the light beam emitted from the light emitting portion of the position indicator only needs to be paid attention to one photodetector, so that the operator can easily operate the position indicator. Especially, in the case of a position indicator provided with a light source having directivity, such an effect is remarkably exhibited.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an optical coordinate input device including an optical position detecting device according to the present invention.

FIG. 2 is a cross-sectional view showing an internal structure of an optical pen type position indicator.

FIG. 3 is a configuration diagram showing an example of an optical position detection device.

FIG. 4 is a diagram for explaining a principle of obtaining a distance to a point light source.

FIG. 5 is a diagram showing an example of a pattern projected on an image pickup surface of an image pickup unit.

FIG. 6 is a waveform chart showing an example of an output signal of the image pickup means.

FIG. 7 is a diagram showing an example of how to obtain the position of the line projection unit.

FIG. 8 is a diagram for explaining how to obtain a magnification and an incident angle of light.

FIG. 9 is a system configuration diagram for explaining an application example of a three-dimensional optical coordinate input device using a CCD area image sensor.

FIG. 10 is a diagram showing an example of a two-dimensional pattern.

FIG. 11 is a diagram for explaining processing of a detection signal of a two-dimensional pattern.

FIG. 12 is a diagram showing another example of a two-dimensional pattern, which is an example of a pattern having characteristics of an M plane.

FIG. 13 is a configuration diagram showing another embodiment of the signal processing circuit for the detection signal of the CCD linear image sensor.

[Explanation of symbols]

 1 CRT display device 2 Optical pen type position indicator 3 Point light source 4 Photodetector 12 Pen tip part 13 Writing pressure detection part 17 Side switch 18 Optical fiber 19 Light emitting diode 21 Pattern board 22 Light receiving element 23 CCD linear image sensor 24 Filter 51 photodetector 52 pattern plate 53 CCD area image sensor 55, 56 point light source

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G06T 7/00 7/60

Claims (14)

[Claims] 1. An image pickup means for detecting the intensity of light,
The light based on the pattern means having a specific pattern arranged on the optical path of the light in front of the imaging means and the detection signal related to the image of the specific pattern projected on the pixel array area of the imaging means. 2. An optical position detecting device, comprising signal processing means for extracting information about a distance in a normal direction to the pixel array area between the light emitting source and the image pickup means. 2. The optical position detecting device according to claim 1, wherein the image pickup means, the pattern means and the signal processing means are unitized as one optical position detecting device. Position detection device. 3. The optical position detection device according to claim 1, wherein the signal processing means obtains the information on the distance based on a pixel signal detection section for extracting a signal on each pixel of the image pickup means and a signal on each pixel. The image pickup unit, the pattern unit, and the pixel signal detection unit are unitized as one device including a processing unit, the processing unit is provided on the host computer side, and the pixel signal detection unit and the processing unit are provided. An optical position detection device characterized by being connected by communication means. 4. The optical position detecting device according to claim 1, wherein the specific pattern is a pattern including equally-spaced portions, and the pattern arrangement direction of the specific pattern and the image pickup means are set. Pixel arrangement directions are the same, and the signal processing means extracts information regarding the distance by obtaining a magnification rate by using the projected image of the specific pattern. . 5. The optical position detecting device according to claim 4, wherein the signal processing means statistically processes signals relating to respective portions of the pattern detected by each of a plurality of pixels included in the imaging means. An optical position detecting device characterized in that the enlargement ratio is obtained. 6. The optical position detecting device according to claim 1, wherein, in addition to the information about the distance, characteristics of an M series or an M plane included in the specific pattern are used. An optical position detecting device is characterized in that information on an incident direction of the light arriving at the pixel array region of the imaging means is extracted. 7. The optical position detecting device according to claim 1, wherein the specific pattern is a two-dimensional pattern created by combining a one-dimensional linear pattern and a one-dimensional linear pattern orthogonal to the one-dimensional linear pattern. The pixel arrangement area of the image pickup means is formed of pixels in a two-dimensional lattice arrangement, and the arrangement directions of vertical and horizontal linear patterns orthogonal to each other in the specific pattern and the arrangement directions of vertical and horizontal pixel arrangements of the image pickup means. Are coincident, and in the signal processing means, by integrating in each of the vertical direction and the horizontal direction of the arrangement of the pixel signals output from the pixels,
An optical position detecting device, characterized in that distance and direction information about one axis is separated and extracted. 8. An optical position detecting device comprising: the optical position detecting device according to claim 6; and a position indicator having a light emitting portion which itself emits light or indirectly emits light. According to the light emitted from the light emitting unit, the distance to the position indicated by the position indicator and the direction of the position are obtained, and the coordinate data of the position is obtained from these distances and directions. Optical coordinate input device. 9. The optical coordinate input device according to claim 8, further comprising a display device for displaying information regarding input coordinates,
An optical coordinate input device, wherein a coordinate input surface designated by the position indicator is a display surface of the display device. 10. The optical coordinate input device according to claim 8, further comprising a display device for displaying information regarding input coordinates.
The optical coordinate input device, wherein the position indicator is used by being attached to a finger of an operator, and the display device displays a display corresponding to the movement of the finger. 11. A shadow of a specific pattern including an equal interval portion is formed on a pixel array area of one image pickup means by light emitted from a point light emitting portion, and a pattern array direction of the specific pattern and pixels of the image pickup means. The arrangement directions are the same, and the distance in the normal direction to the pixel arrangement area between the light emitting unit and the image pickup unit is obtained by obtaining the enlargement ratio based on the detection signal output from each pixel of the image pickup unit. A method for detecting an optical position, which comprises extracting information about 12. The optical detection method according to claim 11, wherein the enlargement ratio is statistically calculated based on detection signals of the plurality of pixels of the imaging unit. 13. The optical position detection method according to claim 11, wherein the specific pattern includes a characteristic of the M series or the M plane, and the characteristic of the M series or the M plane is included in addition to the information about the distance. The optical position detecting method is characterized in that the information on the incident direction of the light arriving at the pixel array region of the image pickup means is extracted based on the information. 14. The optical position detecting method according to claim 13, wherein the coordinates of the point light emitting portion are calculated based on the information on the distance and the information on the incident direction of the light. Position detection method.