JP2003323252A - Optical coordinate input device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical coordinate input device improving operability by suppressing a malfunction due to disturbance light. <P>SOLUTION: This device is provided with a filter means which discriminates whether the detected coordinate value is due to the disturbance light to filter it. To use a radio wave instead of infrared light for transmitting a control signal, an indicating device is provided with a radio wave transmitting means and a detector is provided with a radio wave demodulation means. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device in a large-screen display system, and more particularly to a large-sized personal computer screen, by operating an indicating tool directly on the screen side of the personal computer. The present invention relates to an optical coordinate input device that realizes coordinate input operations such as operations and input of characters and figures.

[0002]

2. Description of the Related Art As a coordinate input device for a large-screen display device, an indicator for emitting light (for example, infrared light) is operated on a screen, and this light is detected by a CC detector.
There is an optical coordinate input device that realizes coordinate input by receiving light by a D (Charge Coupled Device), calculating coordinate values, and transmitting the calculated coordinate values to a personal computer. CCD is a two-dimensional CCD
There is also one using a line CCD and one using a line CCD for the X axis and the Y axis. In such a device, resistance to ambient light in light detection of the detector is required. In order to suppress the influence of ambient light on the CCD, an optical filter that transmits only light of a predetermined wavelength is used, and light when the indicator is lit and light that is not lit is stored separately in the CCD. It is also possible to use a method of removing the disturbance light component that is constantly generated by taking the difference of. Also, CC
Some devices use a position detection element called PSD (Position Sensitive Device) instead of D. In such a device, an optical filter is used, the light intensity is frequency-modulated, and the modulated wave is synchronously detected to cause disturbance. It also controls the effects of light.

[0003]

However, the above-mentioned conventional example is not effective for the disturbance light which is suddenly and partially generated and which is transmitted through the optical filter and inputted. For example, when strong disturbance light is incident on a certain portion at a timing immediately before the signal output from the CCD or PSD is read, the output coordinate value corresponds to the position where the strong disturbance light is incident. Will be. As a result, when a character or a figure is being drawn, the drawing line flies as if an unexpected place was operated, the ambient light disappears immediately, and the drawing line returns to a normal position. Also, if ambient light enters during control signal detection, coordinate position detection processing and control signal detection processing cannot be performed during that time, and the drawing operation of characters and figures is partially interrupted or the operation button clicked is interrupted. If there is no response, smooth operation will be hindered. Further, since the indicator that emits diffused light is usually driven by a battery, there is a problem in that the battery is consumed quickly due to constant light emission.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical coordinate input device in which the influence of ambient light is further suppressed and the operability is better than ever. Another object of the present invention is to provide an optical coordinate input device equipped with an indicator that suppresses battery consumption.

[0005]

According to the present invention, a light emitting device emits light of a predetermined wavelength, an indicator for emitting light of a predetermined wavelength, a light detecting device for integrating detection of the light, and a signal detected by the light detecting device. In an optical coordinate input device comprising coordinate calculation means for outputting a coordinate position signal on the coordinate input surface, a filter means is provided after the coordinate calculation means, and the filter means emits light emitted from the coordinate calculation means. Coordinate memory means for storing coordinate values by a predetermined number of coordinate points before and after the coordinate of interest in the time direction, and distance calculating means for calculating the distance between adjacent coordinate values stored in the coordinate memory means, Disturbance light discriminating means for discriminating whether or not the coordinate value of interest is a coordinate due to ambient light from the inter-coordinate distance group calculated by the distance computing means, and the ambient light discriminating means determines that the coordinate value is due to ambient light. And disable the value for the coordinate value,
An interpolation value calculating means for approximating a coordinate value to replace the coordinate value from the coordinate value in the vicinity thereof is used. As a result, it is possible to suppress erroneous detection of coordinate values due to ambient light that suddenly and partially occurs. Further, by providing the filter ON / OFF means so that the operation of the filter means can be turned ON / OFF, the filter means is turned OFF in the absence of ambient light, the time required for the filtering process is eliminated, and the responsiveness is improved. it can.

Further, according to the present invention, an indicator for emitting light of a predetermined wavelength, a light detecting means for integrally detecting the light, and a coordinate input surface on which the light is emitted from a signal detected by the light detecting means. In the optical coordinate input device including the coordinate calculating means for outputting the coordinate position signal in, the indicator is provided with a radio wave transmitting means for transmitting a control signal for timing control of the light integrating operation in the light detecting means, A control signal demodulating means for receiving a radio wave and generating the timing signal is provided. The use of radio waves eliminates the influence of ambient light on the control signal. Further, the pointing device is provided with a switch input means, the radio wave transmitting means transmits a control signal corresponding to the switch input, and a control signal detecting means for identifying the control signal is provided at a subsequent stage of the control signal demodulating means. Can be prepared. As a result, the influence of ambient light on the detection of the control signal by the switch input is eliminated.

Further, the light emitting operation of the indicator is turned on / off.
Can be provided with a light emission ON / OFF means for controlling independently of the radio wave transmitting means. This allows
When the coordinate position information is unnecessary (for example, when using a slide show of Power Point), the light emitting operation can be stopped and only the control information can be transmitted from the radio wave transmitting means. As a result, the battery life of the indicator can be extended.

[0008]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment) The structure and operation of the optical coordinate input device according to the present invention will be described with reference to FIGS.

(Device Configuration) FIG. 1 is a diagram showing the overall configuration of an optical coordinate input device including a projection type display device 8 which is used at the same time. The projection display device 8 has an image signal processing unit 81 to which an image signal from the computer 9 is input.
And a liquid crystal panel or DMD (Digi
al Mirror Device), an illumination optical system including a lamp 83, a mirror 84, and a condenser lens 85, and a projection lens 86 that projects an image of the display device 82 onto the screen 10. In the optical path projected from the projection lens 86 onto the screen 10, diffused light is emitted from the light emitting section 5 at the tip of the pointing tool 4, and the radio wave transmitting section 1 of the pointing tool 4 is also transmitted.
Radio waves are emitted from 4. The detector 1 is composed of a coordinate detection light-receiving unit 2, a controller 3 for performing control and coordinate calculation of the coordinate detection unit, a control signal detection radio wave reception unit 12 and a demodulation and signal processing unit 13 thereof. The control signal corresponding to the coordinate signal corresponding to and the state of each button of the pointing tool 4 is detected and communicated to the computer 9 via the controller 3. This allows the pointing tool 4 to freely perform mouse input operations such as writing characters and line drawings on the projected display screen, clicking icons, and selecting menus.

(Explanation of Pointing Tool) FIG. 2 is a diagram showing an internal configuration of the optical coordinate input device. The pointing device 4 includes a power switch 43, buttons 44A and 44B which are input sources of control signals,
A light emission ON / OFF switch 45, a transmission signal generating means 47 for generating a transmission signal in response to the input of the button and the switch, a light emission modulating means 46 for performing a modulation process for emitting a diffused light to the generated transmission signal, and a light emission. A light emitting element 41 for emitting the modulated signal as diffused light, a light emitting section 5 incorporating the light emitting element, and a radio wave modulating means 142 for performing a modulation process for transmitting a radio wave to the signal generated by the transmission signal generating means 47. A radio wave transmitting antenna 141 for emitting a radio wave modulated signal as a radio wave. In this embodiment, an infrared light emitting LED is used as the light emitting element 41.
FIG. 3 shows an external view of the pointing tool 4. The operation will be described. The operator holds the indicator 4 in his hand and turns on the power switch 43. When the power switch 43 is turned on, the diffused light is emitted from the light emitting element 41 and the radio wave transmitting antenna 141
The emission of transmitted radio waves is started. At this time, light emission is ON
The / OFF switch 45 is in the ON state, and the diffused light is continuously emitted during this period. Light emission ON / OFF switch 4
The case of turning off 5 will be described later. The diffused light emitted from the light emitting unit 5 is used by the detecting unit 1 to calculate the coordinate value of the light emitting unit 5 with respect to the screen 10 by the process described later, and the calculated coordinate value is transmitted to the computer 9. On the screen 10 screen, the light emitting unit 5 of the pointing device 4
The mouse cursor is displayed at the position corresponding to. At this time, since the buttons 44A and 44B are not operated, the radio transmission signal does not include a control signal by button input, and the header signal and the linear sensor 20X for identifying the signal from the pointing tool 4 are included. Two
Only the signal for generating the 0Y control timing signal is sent. By pressing the button 44A or 44B, the control signal assigned to each button is superimposed on the transmission radio wave. That is, clicking an icon, selecting a menu, drawing a line, a character, or a graphic can be performed by operating the pointing tool 4 near the screen 10 without returning to the side of the personal computer 9.

The data transmitted by radio waves or diffused light is "1"
And "0", but these "1" and "0" are pulse position modulation (Pulse Position) in the transmission signal generating means 47.
Modulation). The PPM method is widely used for general infrared remote controllers, and the data bit is "0".
, "1" is formed so as to have a double interval (corresponding to the CMD signal in FIG. 7). The PPM-modulated signal is input to the light emission modulator 46 and the radio wave modulator 142.
The emission modulation means 46 outputs "Hi" of the PPM-modulated signal.
Further modulation is applied to the level so as to blink at high frequency, and the light is emitted to the space through the light emitting element 41. In the radio wave modulator 142, since the PPM-modulated signal is emitted as a radio wave, frequency modulation is performed at different frequencies for the "Hi" level and the "Low" level (R in FIG. 7).
corresponding to the adio_SG signal). The frequency-modulated signal is emitted into space through the radio wave transmission antenna 141.

By turning off the light emission ON / OFF switch 45, the light emission modulation means 46 stops the light emission operation. At this time, the radio wave modulator 142 turns on the power switch 43.
Is always active. That is, although the light emitting operation is stopped, the control signal can be transmitted by pressing the button 44A or 44B. As a result, if you do not need the coordinate position information of the screen, for example, Microsoft
When only the operation such as page turning of a slide show in a presentation application such as Power Point is required, power consumption due to the light emitting operation can be suppressed. Further, because the fact that the light emission ON / OFF switch 45 is in the OFF state is superimposed on the radio wave and transmitted as one of the control signals, and the detector 1 is forced to stop the calculation of the coordinate position, False detection of coordinate values can be suppressed more reliably.

(Description of Detector) The detector 1 is a radio wave receiving antenna 1 for receiving the radio wave transmitted from the pointing tool 4.
21, control signal demodulation means 131 for demodulating a control signal from the received radio wave, control signal detection means 132 for identifying the demodulated control signal, and visible light with respect to diffused light from the light emitting section 5 of the pointing tool 4. Visible light cut filter 100, cylinder lenses 90X and 90Y for detecting the incident direction of received light, and linear sensors 20X and 2
0Y, a sensor control unit 31 that receives a timing signal from the control signal demodulation unit 131 and controls the linear sensors 20X and 20Y, and an AD conversion unit 3 that converts an analog signal from the linear sensors 20X and 20Y into a digital signal.
1A, coordinate calculation means 32 for calculating the coordinate position of the incident direction of light with respect to the screen 10 from the digital signal from the AD conversion means 31A, filter means 34 for removing the calculated coordinate position due to sudden disturbance light, filter means From the communication control means 33 for transmitting to the connected computer 9 the filter ON / OFF switch 35 for switching ON / OFF of the, the coordinate value calculated via the filter ON / OFF switch 35 and the control signal from the control signal detection means 132 to the connected computer 9. Composed.

The operation will be described. The radio wave emitted from the radio wave transmitting antenna 141 of the pointing tool 4 is received by the radio wave receiving antenna 121, and the control signal demodulating means 131 demodulates a digital signal and generates a timing signal for coordinate position detection. The control signal detection means 132 identifies the header portion of the demodulated digital signal. When it is recognized that the received signal is from the pointing tool 4 based on the header portion, it is transmitted to the sensor control means 31 via the communication control means 33, and the sensor control operation becomes effective. The sensor control means 31 controls the reading of the linear sensors 20X and 20Y according to the generated timing signal. Button 44A in the pointing device 4,
When the 44B or the light emission ON / OFF switch 45 is operated, the control signal corresponding to each switch is superimposed on the radio wave, and this control signal is the control signal demodulating means 131.
After passing through, the signal is decoded by the control signal detection means 132 and sent to the communication control means 33.

The diffused light emitted from the light emitting section 5 of the pointing device 4 passes through the visible light cut filter 100 to eliminate the ambient light, and is then condensed by the cylinder lenses 90X and 90Y, and then on the linear sensors 20X and 20Y. Image on. As shown in FIG. 4, the cylinder lenses 90X, 90
By arranging Y at a right angle, and by arranging the photosensitive section 21X of the linear sensor 20X for detecting the X coordinate on the optical axis of the projection lens 86, the linear sensors 20X and 20Y respectively reflect the X coordinate and the Y coordinate. An output having a peak in the selected pixel can be obtained. These sensors are controlled by the sensor control means 31, and their output signals are AD conversion means 3 provided in the sensor control means 31.
It is digitized by 1 A and sent to the coordinate calculation means 32, and the output coordinate value on the sensor is calculated. By the way, the incident light has its disturbance light cut by the visible light cut filter 100, and the disturbance light also contains light having a wavelength equal to or near the diffused light emitted from the indicator 4. . These lights are transmitted together with the diffused light without being cut by the visible light cut filter 100. For example, although infrared light is used as the diffused light in this embodiment, the infrared light near the wavelength of the diffused light is also included in the sunlight from the window in the installation environment of the device and the light from the indoor inverter lighting equipment. Light is included, and these reach the linear sensors 20X and 20Y together with the diffused light. Normally, the intensity of the disturbance infrared light is lower than that of the peak portion in the original diffused light, and the peak value detection by the coordinate calculating means 32 does not interfere. In addition, even if the level is somewhat high, it can be dealt with by constantly subtracting the level of the disturbance infrared light when the diffused light is not turned on from the total light level when the diffused light is turned on.

However, the intensity of the disturbance infrared light differs depending on how the sunlight enters, the type of the inverter illuminator, the installation relationship of the detector 1 with respect to the disturbance light, and depending on the situation, it may be stronger than the diffused light. It can occur suddenly. As a result, erroneous detection of the peak location in the coordinate calculation will occur. For example, there is a case where the disturbance infrared light is not incident when the diffused light is not lit but is suddenly incident when the diffused light is lit. At this time, the mouse pointer on the screen 10
For a moment, it jumps to the coordinate position erroneously detected by the ambient light and returns to the position corresponding to the light emitting unit 5 of the original pointing tool 4 again. This kind of operation would not be a problem unless the buttons 44A and 44B are operated, but if this is for example drawing a free line, the line being drawn suddenly jumps in an unexpected direction. This means returning to the original position again, which causes a hindrance to the drawing operation. Therefore, in order to suppress the erroneous detection of the coordinates due to such a sudden disturbance infrared light as much as possible, a filter means 34 and a filter ON / OFF means 35 are provided at the subsequent stage of the coordinate calculation means 32.

(Operation of Filter Means) Filter Means 34
The operation of will be described. FIG. 5 is a diagram showing the internal configuration of the filter means 34. The coordinate value (X, Y) output from the coordinate calculation means 32 is held in the coordinate memory means 34a. The distance calculation means 34b calculates the inter-coordinate distance between the held coordinate value and the previous coordinate value and holds the calculated coordinate distance.
Then, by determining whether the calculated inter-coordinate distance is larger or smaller than a certain distance, it is detected whether or not the input coordinate value is due to ambient light. This discrimination is performed by the ambient light discrimination means 34c. If it is determined that the light is ambient light, the coordinate value is invalidated, and the coordinate value is obtained by performing an interpolation process from the correct coordinate values before and after it.

A specific example will be described with reference to FIG. The memory array of the coordinate memory means 34a is Zahyo (N), and the memory for inter-coordinate distance calculated by the distance calculation means 34b is Kyo.
ri, the memory array of the ambient light discrimination means 34c is changed to Hanbe
tsu (N), the ambient light detection flag memory of the ambient light discrimination means 34c is Gairan. Zahyo (N),
Kyori, Hanbetsu (N), and Gairan each have N, 1, N, and 1 memory areas.
The latest Zahyo () and Hanbetsu () are all held at the Nth position, but the data before that is shifted to the next lower region in advance. First, the latest coordinate value is stored in Zahyo (N) of the coordinate memory means 34a (S
102). Next, in the distance calculation means 34b, Zahy
The distance between the coordinate values of o (N) and Zahyo (N-1) is Kyori = {Zahyo (N) -Zahyo (N-
1)} ^ 2 and calculated and held (S103). This Kyo
Whether or not the value of ri is larger than a certain distance TH2 is compared (S104), and when it is larger, it is determined that the coordinate value of Zahyo (N) is generated by ambient light.
This discrimination processing is performed by the ambient light discrimination means 34c.
When no sudden disturbance light is incident, each coordinate value runs on a continuous smooth line, and the distance between each coordinate (coordinate movement amount per unit sampling: Kyori)
Does not exceed a certain distance TH2 unless the indicator 4 is operated at a very high speed. On the other hand, when sudden disturbance light is incident, this continuity is broken and the inter-coordinate distance becomes extremely large.

When it is determined that Zahyo (N) is caused by ambient light, Hanbetsu (N) indicating that the coordinate value is due to ambient light is set to "1" (S105), and Hanbetsu is set. To make it possible to immediately determine that "1" exists in the flag string of (), "1" is also set in Gairan (S10
5) After outputting the determined coordinate value (S106), the process moves to the next sample coordinate value.

Hanb when it is not discriminated as ambient light
Set "0" to etsu (N) (S108), and Ga
iran is determined (S109). If Gairan = 0, there has been no coordinate value due to ambient light until now, and the determined coordinate value is output as it is (S106). Gaira
When n = 1, at least Hanbetsu (N
−1) = 1, and the nearest n−1 Hanbetsu (n) = 0 is searched for (S110).
For example, in the case of n = N-5, from the N-4th to N-1
It is determined that the four coordinates up to the th are due to ambient light. Here, for these four coordinate values,
Numerical values are interpolated from correct coordinate values before and after that (S1)
11). As the interpolation processing, for example, simply Zahyo (N
-5) and Zahyo (N) are connected by a straight line, and interpolation is performed so that the coordinates due to ambient light are evenly arranged between them.
Or Zahyo (N-6) and Zahyo (N-5)
Then, a quadratic function that passes through the three coordinate values of AZ and Zahyo (N) is obtained, and interpolation is performed so that the coordinates are evenly arranged on this quadratic function. Of course, the accuracy of interpolation can be improved by increasing the number of normal coordinate values used for interpolation. After the interpolation processing, each interpolation value is held in the corresponding Zahyo () (S11
1), Hanbetsu () and "1" of Gairan
Is set to "0" (S112), and the determined coordinate value is output (S106). After outputting the determined coordinates, Zahyo () and Hanbetsu () are processed for processing the next sample coordinate values.
Shifts all the data in the lower one area (S
107). This resulted in Zahyo (N) and Hanbet
su (N) becomes empty, and Zahyo (1) and H
The data of anbetsu (1) will be discarded.

Here, the number N of memory arrays may be adjusted / set according to the algorithm of this interpolation processing. The final determined coordinate value is a predetermined f-th coordinate value Zahyo (f) that is output as a final coordinate value out of N coordinate values held for filter processing. It may be adjusted / set according to the algorithm of the interpolation processing and the number N of memory arrays. However, in the above description, the coordinate value due to the disturbance light generated at a small distance between the coordinates cannot be distinguished from the actual operation, and the coordinate value cannot be removed.

(Control signal demodulation operation) In the conventional optical coordinate input device, the control signal is also detected from the same infrared light as that for detecting the coordinate position. For this reason, as in the case of coordinate detection, it was easily affected by ambient light. Since it is not recognized as the original control signal due to the influence of ambient light, the buttons 44A and 4
Even if 4B is operated, this is not reflected on the display screen, that is, the mouse pointer for drawing is stopped in the middle of drawing, or it is not reflected even if the icon is clicked. It will be. Therefore, in this case, the control signal is transmitted by radio waves. In this embodiment, pulse position modulation (Pulse Positi
In the infrared light system using on modulation, the Hi level and the Low level of the baseband signal immediately before being modulated by the infrared light are modulated by radio waves having different frequencies. FIG. 7 shows the radio wave receiving antenna 12
6 is a timing chart of signal waveforms showing an operation of demodulating a control signal from the No. 1 received signal. Radio_SG is an output signal from the radio wave receiving antenna 121, and is an indicator 4
By turning on the power switch 43 of the radio wave modulation means 1
Corresponds to the signal generated from 42. Radio_SG
The CMD signal is obtained by demodulating the digital signals of "Hi" and "Low" from the signal. The CMD signal is a PPM-modulated signal, and has a slightly longer "Hi" and "" at the beginning.
"Low" is the reader part, and the header signal consisting of this reader part and the code (manufacturer ID, etc.) following this is output first, followed by the transmission data string such as control signals. The combination of "and" Low "represents the data bit" 0 "," Hi "and its triple width"
The combination of "Low" represents the data bit "1". In the indicator 4, it corresponds to the signal generated by the transmission signal generating means 47. The CMD signal is the control signal detecting means 132.
Is interpreted as a control signal and sent to the communication control means 33. Further, the Light_SG signal corresponds to a signal generated by the light emission modulation means 46 of the indicator 4, and is not detected and processed as a digital signal by the detector 1, but an instruction is given when this signal is at “Hi” level. This means that the light emitting element 41 of the tool 4 is turned on, and the diffused light reaches the linear sensors 20X and 20Y at this time. When the light emission ON / OFF switch 45 of the pointing tool 4 is in the OFF state, the Light_SG signal is not generated, so that the diffused light does not reach the linear sensors 20X and 20Y.
Further, the fact that the switch 45 is in the OFF state is also detected by the control signal detecting means 132, and based on this, the sensor control means 31 and the coordinate calculating means 32 stop the coordinate position detecting operation. As a result, the light emission ON / OFF switch 45 is OF
False detection due to ambient light at the coordinate position at F is completely suppressed.

Next, the phase synchronization of the sensor will be described.
CLK that is reset at the timing of the header part of the CMD signal and is phase-synchronized with the trailing edge of the CMD signal.
A signal is generated. This CLK signal means that it is a clock signal of a constant frequency synchronized with the presence or absence of radio waves.
Also, from the CMD signal, a Rad indicating the presence or absence of radio wave input
The io_ON signal and the sensor reset signal CLR activated by this Radio_ON signal are generated. Two linear sensors 2 while this CLR signal is "Hi"
0X and 20Y are reset, and the synchronous integration operation described later is started at the timing of the falling edge of the CLR signal synchronized with the rising edge of the CLK signal. On the other hand, when the control signal detection means 132 detects the header and confirms that the radio wave input from the pointing tool 4 has started, not to other devices or noise, this is transmitted to the sensor control means 31 to indicate that the sensor operation is valid. Integ_ON is set to "Hi", and the operation of the coordinate calculation means 32 is started. FIG. 8 shows a timing chart of the signal waveform when the radio wave input signal Radio_SG disappears and a series of operations ends. Rad
The demodulated signal CMD detected from the io_SG signal is “Lo
If "w" is continued for a certain period of time or more, R indicating the presence or absence of radio wave input is displayed.
The audio_ON signal becomes “Low”, and Integ_
The ON signal also becomes "Low", and the coordinate output operation ends.

Next, the synchronous integration operation of the linear sensors 20X and 20Y will be described. By the way, the sensor used in this embodiment has an array shape and is capable of performing a synchronous integration operation. FIG. 9 is an internal configuration diagram of the linear sensors 20X and 20Y. Since the two for X and the one for Y are the same, the following description will be made for only one.

The sensor array 21, which is a light receiving portion, is composed of N pixels, and the charge corresponding to the amount of received light is stored in the integrating portion 22. The integrator 22 can be reset by applying a voltage to the gate ICG, so that the electronic shutter operation can be performed. The electric charge stored in the integrating unit 22 is applied to the electrode ST.
Is transferred to the storage unit 23 by applying a pulse voltage to.
There are 2N storage units 23, and the CL is synchronized with the blinking of light.
Charges are separately accumulated in correspondence with "Hi" and "Low" of the K signal. After that, the charges accumulated in the 2N-stage linear CCD unit 25 are transferred through the shift unit 24 provided to simplify the transfer clock. In this way, in the linear CCD unit 25, the electric charges corresponding to the blinking of the light output from the sensor output of N pixels are arranged side by side. Linear CC
The charges arranged in the D section 25 are sequentially transferred to the ring CCD section 26. The ring CCD 26 is emptied by the CLR section 27 by the CLR signal described above, and then the linear CCD 2
The charges from 5 are accumulated in sequence. Reference numeral 29 is an amplifier for reading out this electric charge, which outputs a voltage which is non-destructive and which is proportional to the accumulated electric charge amount.

FIG. 10 is a diagram showing an example of this output waveform. When only the signal at the time of lighting (when the CLK signal is "Hi") is read, the waveform of B, the waveform at the time of non-lighting, that is, only the disturbance light is shown. At this time (when the CLK signal is “Low”), a waveform of A is obtained, and the charges of these corresponding pixels are arranged adjacent to each other in the ring CCD 26. Therefore, the amplifier 29 actually calculates the difference between the adjacent transfer stages. The output waveform is nondestructively amplified, and the output waveform is a signal of an image of only the blinking light from the indicator 4 because the disturbance light component is canceled and the noise is suppressed as shown in B-A. To be The maximum value of this waveform is successively accumulated in the ring CCD 26 by repeated blinking and becomes large, so that this level becomes a predetermined value T.
By detecting the reaching of H1, it is possible to always obtain an output waveform of constant quality. Note that this determination may be made separately for the two sensors for X and Y, but since they are placed very close to each other, almost the same amount of light is incident, so the output peaks are almost the same. Therefore, in this example, the circuit is simplified by performing the determination with only one output and performing the same control for both sensors.

Further, when the ambient light is very strong, the ring CCD is detected before the peak of the differential waveform becomes sufficiently large.
The transfer charge of 26 may be saturated. For such a case, the sensor is provided with a skim function. FIG. 11 is a diagram showing the skim operation. The skim unit 28 monitors the level of the non-lighting signal, and when the signal level exceeds the predetermined value at the nth time (two-dot chain line in the figure), a certain amount of electric charge is extracted from each of the A and B pixels. Act on. Therefore, the next n + 1-th time has a waveform such as An + 1, and by repeating this, the signal charge is continuously accumulated without being saturated even if there is extremely strong ambient light. Therefore, even if the amount of blinking light is weak, it is possible to obtain a sufficiently large signal waveform by continuing the integration operation many times.

The two linear sensors 2 thus obtained
The 0X and 20Y signals (differential signals) are the sensor control means 3
The n-bit (8-bit in this example) AD conversion means 31A provided in 1 sends the digital signal to the coordinate calculation means 32 to calculate the coordinates. The coordinate calculation is based on the coordinate value (X1, Y) on the sensor for each output data in the X and Y directions.
1) is required. Since it is similar to X and Y, its processing flowchart for only X is shown in FIG. First, in step S202, the difference data Dx (1)-
Dx (N) is read and stored in the buffer memory. Next, in step S203, pre-filtering is performed in order to further suppress noise and improve S / N. This is a very simple addition well known as the neighborhood operator (1,2,1). Next, in step S204, the larger pixel of the maximum value and the values before and after the maximum value is searched for, and the pixel numbers thereof are set to nx and nx + 1. The exact position between the pixels of the peak is obtained by using one of the differential operators (1, 1, 0, -1, -1). This calculation is to obtain the zero cross of the differential waveform, but the simple formula rearranges the formula into a very simple form shown in step 205.

[0030]

[Equation 1] However, −0.5 <GX ≦ 0.5 step. The sum of the inter-pixel coordinates Gx thus obtained in S206 and the pixel number nx is the sensor output coordinate X1. Also for Y1, Y1 = Gy + ny can be obtained similarly to X1.

Next, calibration is performed using the user calibration function to obtain output coordinate values (X, Y). This user calibration is a conversion by a simple linear function, and when the user designates three points (or more) on the screen that are predetermined in the calibration value setting mode when the installation state is changed, The coefficient of the function is determined as the solution of the simultaneous equations of three elements (if there are four points or more, a fitting method such as the least square method may be used). Such a user-installed calibration is a method generally performed by the coordinate input device and is not unique to the present invention, and thus a detailed description thereof will be omitted. In addition, it is an indispensable function when the installation is changed frequently.

The output coordinate values (X, Y) and data such as control signals obtained as described above are used as communication control means 33.
Various operations such as input of a cursor or menu on the screen projected by the projection display device 8 and input of characters and line drawings can be performed by a command transmitted from the computer 9 by a predetermined communication method.

[0033]

As described above, according to the present invention, the filter processing is provided in the time direction in the calculation of the coordinate position from the diffused light emitted from the pointing tool. Therefore, erroneous detection of the coordinate position due to sudden disturbance light can be suppressed. In addition, since transmission and reception of the control signal is performed by using radio waves instead of diffused light, erroneous detection of the control signal due to ambient light is eliminated. Further, the indicator is provided with a light emission ON / OFF switch so that the light emitting operation of the indicator can be stopped when the coordinate position detection is unnecessary, so that the power consumption of the indicator in the use situation can be suppressed. It was

[Brief description of drawings]

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

FIG. 2 is a diagram showing an internal configuration of an optical coordinate input device according to an embodiment of the present invention.

FIG. 3 is an external view of the pointing tool 4 according to the embodiment of the present invention.

FIG. 4 is a linear sensor 2 according to an embodiment of the present invention.
It is a figure showing arrangement | positioning of 0X and 20Y.

FIG. 5: Filter means 34 in an embodiment of the invention
It is a figure showing the internal structure of.

FIG. 6 is a filter means 34 according to an embodiment of the present invention.
2 is a processing flowchart of FIG.

FIG. 7 is a timing chart of signal waveforms showing an operation of restoring a control signal from a received signal of the radio wave receiving antenna 121 according to the embodiment of the present invention.

FIG. 8 is a timing chart of signal waveforms at the end of the operation of demodulating a control signal in the embodiment of the present invention.

FIG. 9 is a linear sensor 2 according to an embodiment of the present invention.
It is an internal block diagram of 0X and 20Y.

FIG. 10 is a diagram showing an example of output waveforms of the linear sensors 20X and 20Y in the embodiment of the present invention.

FIG. 11 is a diagram showing a skim operation of the linear sensors 20X and 20Y according to the embodiment of the present invention.

FIG. 12 is a coordinate calculation means 3 according to the embodiment of the present invention.
It is a processing flowchart of 2.

[Explanation of symbols] 1 detector 20X linear sensor X 20Y Linear sensor Y 31 sensor control means 31A AD conversion means 32 coordinate calculation means 33 communication control means 34 Filter means 35 Filter ON / OFF switch 4 Indicator 41 light emitting device 43 Power switch 44A Button A 44B Button B 45 Light emission ON / OFF switch 46 emission modulation means 47 transmission signal generation means 5 Light emitting part 90X, 90Y cylinder lens 100 visible light cut filter 121 Radio wave receiving antenna 131 Control signal demodulating means 132 Control signal detecting means 141 radio wave transmitting antenna 142 Radio wave modulator

Claims (4)

[Claims] 1. A coordinate on the coordinate input surface from which the light is emitted from an indicator that emits light of a predetermined wavelength, a light detector that integrally detects the light, and a signal detected by the light detector. In an optical coordinate input device comprising a coordinate calculating means for outputting a position signal, a filter means is provided at a stage subsequent to the coordinate calculating means, and the filter means stores a predetermined number of coordinate values output from the coordinate calculating means. Coordinate memory means, distance calculating means for calculating a distance between adjacent coordinate values stored in the coordinate memory means, and coordinate values input from the inter-coordinate distance group calculated by the distance calculating means Disturbance light discriminating means for discriminating whether or not the coordinate value is determined by the disturbance light discriminating means, and invalidating the coordinate value discriminated by the disturbance light discriminating means to be the coordinate value due to the disturbance light, and replacing the coordinate value with that. Optical coordinate input apparatus characterized by being composed of the interpolated value calculating means for approximating calculated from the coordinate values beside. 2. ON / OFF of operation of the filter means
2. The optical coordinate input device according to claim 1, further comprising a filter ON / OFF unit for switching between. 3. A pointing device that emits light of a predetermined wavelength, a light detecting unit that integrally detects the light, and a coordinate position on a coordinate input surface where the light is emitted from a signal detected by the light detecting unit. In an optical coordinate input device comprising a coordinate calculation means for outputting a signal, a radio wave for transmitting a control signal for timing control of a light integration operation in the light detection means and a control signal for operation from an indicator by radio waves. Equipped with a transmitting means in the pointing device,
An optical coordinate input device comprising: a control signal demodulating means for receiving the radio wave and generating the timing signal; and a control signal detecting means for identifying a control signal from the pointing tool. 4. The optical coordinate input device according to claim 3, wherein the pointing device includes a light emission ON / OFF unit capable of controlling ON / OFF of light emission independently of the radio wave transmission unit.