JPH08114666A - Method and apparatus for measuring position - Google Patents

Abstract

PURPOSE: To accurately measure a position in a short measuring period in a wide range by providing transmitters for intermittently transmitting substantially simultaneously different frequency ultrasonic waves, a receiver for detecting the transmitters via narrow band characteristic filters, a position measuring processor, etc. CONSTITUTION: A transmitting apparatus 23 intermittently transmits substantially simultaneously ultrasonic bursts having different frequencies from transmitters 3, 5. A receiving apparatus 24 detects reception signals E of an indicating member 8 according to the transmitters for the ultrasonic waves of the transmitters 3, 5 via narrow band characteristic filters 31a-31c having different central frequencies. A two-dimensional or three-dimensional position is measured by switching the mode selection button 16 of the member 8, two-dimensional or three-dimensional information is transmitted to a controller 13, a direction regulator 7, a television camera 6, an image display unit 10 are controlled based on position information of them, switch signal information, etc., from the member 8, thereby controlling the image display of a screen.

Description

Detailed Description of the Invention

[0001]

This invention uses ultrasonic waves.
The present invention relates to a three-dimensional or three-dimensional position measuring method and device.

[0002]

2. Description of the Related Art As a position measuring method of this kind, ultrasonic waves of a constant frequency are intermittently transmitted from one transmitter attached to an object to be measured, and the ultrasonic waves are arranged at predetermined intervals. The elapsed time from the start of ultrasonic wave transmission by the transmitter to the ultrasonic reception time by each receiver is measured, and the distance from the transmitter to each receiver is calculated based on these times. It is known that the position of the measured object is obtained based on these distances. In this case, three receivers are used for three-dimensional position measurement and two receivers are used for two-dimensional position measurement.

Further, the relationship between the transmitter and the receiver is reversed from the above, and ultrasonic waves are intermittently transmitted from a plurality of transmitters arranged at predetermined intervals, and these ultrasonic waves are transmitted to the object to be measured. Received by one attached receiver, measure the elapsed time from the ultrasonic transmission start time by each transmitter to the ultrasonic reception time by the receiver, and based on these times, the measured object as above It is also known to seek the position of. Also in this case, three transmitters are used for three-dimensional position measurement and two transmitters are used for two-dimensional position measurement.

[0004]

In the former method of mounting the transmitter on the measured object, one transmitter is used.
Since one ultrasonic burst is received by a plurality of receivers and the distance to the transmitter can be measured at each receiver at the same time, the measurement cycle can be shortened. However, depending on the relative angle between the transmitting surface and the receiving surface, there is a problem that the influence of the reflected wave is strong and a measurement error occurs. Also, considering the case of measuring the positions of multiple measured objects, assuming that the ultrasonic waves of the same frequency are simultaneously transmitted from the transmitters attached to each measured object, which ultrasonic wave is received by each receiver is transmitted. I can't tell if it's from a bowl. Therefore, it is necessary to transmit ultrasonic waves of different frequencies from the transmitters of the plurality of measured objects, or to measure the positions of the plurality of measured objects in a time division manner. Position measurement is difficult. Furthermore, since the transmitter is mounted on the measured object side, it is difficult to make the measured object cordless.

The latter method of mounting the receiver on the object to be measured does not have the above problem, but has the following problem. That is, when the frequencies of the ultrasonic waves transmitted from a plurality of transmitters are the same, if the ultrasonic waves are simultaneously transmitted from the respective transmitters, it is impossible to distinguish which transmitter the ultrasonic wave received by the receiver is from. Therefore, it is necessary to time-divisionally transmit the ultrasonic waves from each transmitter and measure the distance. By the way, when the three-dimensional position measuring method is applied to a presentation device such as a conference room or an event venue, in a relatively wide space of about 3 m on a side, the measuring cycle is about 20 msec and the measuring accuracy is about ± 1 m. It is necessary to measure the position of. However, as mentioned above, 3
If the distance from each transmitter is measured in a time-division manner, it takes 9 msec for an ultrasonic wave to propagate a distance of 3 m for one transmitter, and for three transmitters,
It takes 27msec to propagate the ultrasonic waves,
The measurement cycle cannot be 20 msec or less. Three
If the frequencies of the ultrasonic waves transmitted from the individual transmitters are different from each other, the ultrasonic waves can be simultaneously transmitted from these transmitters, and position measurement in a relatively wide space can be performed with a measurement cycle of about 20 msec. By the way, especially when three-dimensional position measurement is performed, it is not preferable that the directivity of ultrasonic waves is strong. However, as the frequency of ultrasonic waves increases, the directivity becomes stronger, and the frequency of ultrasonic waves that can be used for position measurement in a three-dimensional space becomes approximately 40 kHz or less. Further, in order to distinguish it from the audible band, a high frequency of about 25 kHz or higher is required. Therefore, the frequencies of ultrasonic waves that can be actually used are relatively close to, for example, 40, 32, and 25 kHz. When using ultrasonic waves of such close frequencies, it is difficult to completely separate the ultrasonic waves of each frequency with a normal bandpass filter, and it is affected by other ultrasonic waves and external noise. However, there is a problem that the measurement accuracy decreases. Therefore, again, it is difficult to perform highly accurate position measurement in a relatively wide space with a relatively short measurement cycle.

The object of the present invention is to solve the above problems,
It is an object of the present invention to provide a position measuring method and device capable of accurately measuring a wide range of positions in a short measurement cycle by using a method of mounting a receiver on an object to be measured.

[0007]

In the position measuring method according to the present invention, ultrasonic waves having different frequencies are intermittently and almost simultaneously transmitted from a plurality of transmitters arranged at a predetermined interval, and these ultrasonic waves are transmitted. Is received by one receiver attached to the object to be measured, the received signal of the receiver is passed through a plurality of band-pass filters having narrow band characteristics having different center frequencies, and the signals are separated for each ultrasonic wave from each transmitter. Received signals are individually detected, and the distance from each transmitter to the receiver is calculated based on the elapsed time from the start time of ultrasonic wave transmission by each transmitter to the detection time of the corresponding received signal for each transmitter. It is characterized in that the position of the measured object is obtained based on the distance.

The position measuring apparatus according to the present invention intermittently transmits ultrasonic waves having different frequencies from a plurality of transmitters arranged at a predetermined interval, one receiver attached to the object to be measured, and each transmitter. And transmit the received signals of the transmitter and the receiver, which are transmitted almost simultaneously, through the band-pass filters having a plurality of narrow band characteristics having different center frequencies, and individually detect the received signal for each ultrasonic wave from each transmitter. Processing for obtaining the distance from each transmitter to the receiver and the position of the object to be measured based on the elapsed time from the transmission start time of the ultrasonic wave by each receiver and the detection time of the corresponding reception signal for each transmitter by each transmitter It is characterized by having a device.

Preferably, the band-pass filter includes two piezoelectric ultrasonic transducers having the same frequency as the corresponding ultrasonic waves, and the resonators of these ultrasonic transducers face each other with a distance of about one wavelength of the corresponding ultrasonic wave. The input signals are applied to the electrodes of one transducer and the output signals are taken out from the electrodes of the other transducer.

[0010]

According to the method and apparatus of the present invention, ultrasonic waves having different frequencies are simultaneously transmitted from a plurality of transmitters, and the distances from the transmitters to the receivers are measured at substantially the same time. The measurement cycle can be shortened as compared with the case where the distance from the instrument is measured in time division. Further, the received signal of the receiver is passed through a band-pass filter having a plurality of narrow band characteristics having different center frequencies, and the received signal of each transmitter with respect to the ultrasonic wave from each transmitter is individually detected. Even if ultrasonic waves are used, they are less affected by other ultrasonic waves and external noise, and highly accurate measurement is possible.

The band-pass filter is provided with two piezoelectric ultrasonic transducers having the same frequency as the corresponding ultrasonic waves, and the resonators of these ultrasonic transducers are arranged facing each other with a distance of about one wavelength of the corresponding ultrasonic wave. When the input signal is applied to the electrode of one transducer and the output signal is taken from the electrode of the other transducer, the blocking characteristics are excellent and the effect of other ultrasonic waves and external noise is eliminated. It is possible to receive less, and it becomes possible to perform highly accurate measurement.

[0012]

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

FIG. 1 schematically shows an example of the appearance of a presentation device using the method and device of the present invention. FIG. 2 shows a functional configuration of the presentation device.

This presentation device is installed in a room such as a conference room or an event site. The external appearance of the presentation device is the display screen (2) provided at a predetermined location on the wall surface (1) of the room.
(2) Two transmitters for two-dimensional measurement (3a) (3b), which are arranged at the above two places with a predetermined interval, and three places on the ceiling surface (4) in the room, with a predetermined space The three three-dimensional measurement transmitters (5a) (5b) (5c) arranged, the TV camera (imaging device) (6) and the TV camera (6) which are arranged at predetermined positions on the ceiling surface (4). A direction adjusting device (7) for changing the direction, an indicating member (8) for a speaker (not shown) to operate by hand, an image display device (10) installed on an indoor desk (9), etc. And a control unit (11). Two-dimensional measurement transmitters (abbreviated as two-dimensional transmitters) are collectively denoted by the code (3), and when it is necessary to distinguish them, the two-dimensional first transmitters are used.
(3a) and the second transmitter (3b). Three-dimensional measurement transmitters (abbreviated as three-dimensional transmitters) are generically denoted by reference numeral (5), and when it is necessary to distinguish them, the three-dimensional first transmitter (5a) and the same three-dimensional transmitter (5a) 5b) and the third transmitter (5
We will call it c). The function of the presentation device is the screen (2), the pointing member (8), the position measuring device (1
2), an image display device (10), a television camera (6), an orientation adjusting device (7) and a control device (13).

The display screen (2) is not limited to that of this embodiment as long as it can display an image.
For example, a blackboard-shaped display plate may be used as the display screen. Also, a white wall surface may be used as a display screen. In that case, the presentation device need not have a separate display screen.

The image display device (10) is for displaying a desired image on the screen (2) based on a control signal, image information and the like from the control device (13), and for example, a known liquid crystal projector. And so on.

The television camera (6) is attached to the ceiling surface (4) via an orientation adjusting device (7). Orientation device
(7) is an azimuth angle adjusting servo mechanism (first servo mechanism) (7a) for adjusting an angle (azimuth angle) in a horizontal plane about the vertical axis, and a vertical plane about the horizontal axis. An elevation angle adjusting servo mechanism (second servo mechanism) (7b) for adjusting an angle (elevation angle) inside is provided. Then, by adjusting the azimuth angle with the first servo mechanism (7a) and adjusting the elevation angle with the second servo mechanism (7b), the orientation of the television camera (6) can be arbitrarily adjusted. Has become.

The indicating member (8) is a screen for a speaker or the like.
(2) It is for instructing the above two-dimensional position and the three-dimensional position in the room space, switching the measurement mode described later, various operation commands, etc., and is measured by the position measuring device (12). It is an object.

The position measuring device (12) uses the pointing member (8) based on the measurement mode switching information from the pointing member (8).
This is for selectively measuring the two-dimensional position on the screen (2) designated by and the three-dimensional position in the space.

The control device (13) includes an orientation adjusting device (7) and a television camera based on the operation command information from the pointing member (8) and the three-dimensional position information measured by the position measuring device (12).
Control of (6), operation command information from the pointing member (8), two-dimensional position information measured by the position measuring device (12), TV camera
It is for controlling the image display device (10) based on the image signal from (6). Although not shown, the control device (13) includes a microcomputer (not shown),
Further, an appropriate external storage device, an output device such as a printing device, and the like are provided as necessary. Three-dimensional position information of the television camera (6) in space is preset in the control device (13). The control device (13) is functionally
The image transformation means for performing the image transformation described later is provided.

Details of the external appearance of the indicating member (8) are shown in FIG. 3, and details of its electrical configuration are shown in FIG. The indicating member (8) is provided with a rod-shaped case (14) that is slightly bent at a portion closer to the base end than the middle of the length and extends linearly from this bent portion toward the base end and the tip. .
An omnidirectional microphone (hereinafter abbreviated as microphone) (15) is attached to the tip of the case (14). The microphone (15)
It is omnidirectional and is composed of, for example, an electret condenser microphone that has sufficient reception sensitivity even for sounds in the ultrasonic band of about 40 kHz, and constitutes the receiver of the position detection device (12) described later. There is. A mode selection button (16), an upper button (17) and a lower button (18) are attached to the bent portion of the case (14). At the tip of the case (14),
In addition, the tip contact detection switch (abbreviated as tip switch) (1
9) is installed. The mode selection button (16) is a self-holding type changeover switch that is switched between an on (closed) state and an off (open) state and held in each state.
The other buttons (16), (17) and (18) and the switch (19) are self-resetting push button switches that are turned on only while being operated. The microphone (15), buttons (16) (17) (18) and switch (19) are connected to the cable (20) and connector (21) connected to the proximal end of the indicating member (8) as described in detail later. ) Is connected to a required portion of the control unit (11). The mode selection button (16) is for switching the two-dimensional measurement mode (abbreviated as two-dimensional mode) and the three-dimensional measurement mode (abbreviated as three-dimensional mode) of the position measuring device (12) described later. Up button (17) and Down button (18)
Is for performing various operation commands described later.
The tip switch (19) is designed so that the tip of the pointing member (8) is on the screen when inputting handwriting which will be described later on the screen (2).
It is for detecting the contact with (2).

The position measuring device (12) comprises the above-mentioned two-dimensional transmitter (3), three-dimensional transmitter (5) and microphone (15), mode switching device (22), transmitting device (23), Receiver (24)
And a processor (25). Position measuring device (12) except transmitter (3) (5) and microphone (15) and control device (1
3) is built in the control unit (11).

Each of the transmitters (3) and (5) is composed of, for example, a piezoelectric ultrasonic transducer. 2D and 3
The natural frequency wave of the first dimension transmitter (3a) (5a) is 25 kHz
The natural frequency wave of the second transmitters (3b) and (5b) for z, two-dimensional and three-dimensional is 40 kHz and the natural frequency wave of the third transmitter (5c) for three-dimensional is 32 kHz.

The transmitting device (23) has two-dimensional transmitters (3) or three-dimensional transmitters (5) depending on a measurement mode described later.
Is to intermittently and almost simultaneously transmit ultrasonic bursts having different frequencies, and is provided with three transmission circuits (26a) (26b) (26c) and a 50 Hz transmission control oscillation circuit (27). There is. The transmission circuit is collectively referred to by the code (26),
When it is necessary to distinguish them, the first transmission circuit (26
a) will be referred to as the second transmission circuit (26b) and the third transmission circuit (26c). The oscillating circuit (27) is for controlling the transmission interval of ultrasonic bursts, and transmits the transmission start pulse signal A every 20 msec to each transmitting circuit (26) and receiving device (2).
4) and the processing unit (25). Each transmitter circuit (26)
When the transmission start pulse signal A is input from the oscillator circuit (27), the transmission signals B1, B2 and B3 having constant frequencies are output for several cycles. Although illustration is omitted, each transmission circuit (26) has, for example, an oscillation circuit that constantly outputs a transmission pulse signal of a constant frequency, and a gate that opens for a certain time when the transmission start pulse signal A is input. Transmission pulse signal of several cycles, transmission signal B1 ~
It has a gate circuit that outputs as B3. Further, each transmission circuit (26) synchronizes with the rising edge of the first pulse of the transmission signals B1 to B3, and the measurement start pulse signal C1
, C2, C3 are output. The frequencies of the transmission signals B1 to B3 are 25 kHz for the first transmission circuit (26a) and the second transmission circuit.
(26b) is 40kHz, 3rd transmission circuit (26c) is 32kHz
Is. Actually, the transmission signal B1 of each transmission circuit (26)
The frequencies ~ B3 are detuned slightly above the natural frequencies of the corresponding transmitters (3) (5). That is, the actual frequencies of the transmission signals B1 to B3 are, for example, 25.2 kHz for the first transmission circuit (26a), 40.4 kHz for the second transmission circuit (26b), and 32.3 kHz for the third transmission circuit (26c).
Is set to In addition, the transmission signal B of each transmission circuit (26)
The levels of 1 to B3 are controlled on the basis of transmission level control signals D1, D2 and D3 from a processing device (25) described later. An example of the transmitted signal B2 is shown in FIG.

The mode switching device (22) is based on the state of the mode selection button (16) of the indicating member (8), and is based on the screen.
(2) It is for switching between the two-dimensional mode for measuring the two-dimensional position above and the three-dimensional mode for measuring the three-dimensional position in the space of the room, and the first transmission circuit (26a) is the first for the two-dimensional 2D measurement state connected to transmitter (3a) and 1st transmitter for 3D
The first changeover switch (28) for switching to the three-dimensional measurement state connected to (5a) and the second transmitting circuit (26b) are used for the second two-dimensional measurement.
A second changeover switch (29) for switching between a two-dimensional measurement state connected to the transmitter (3b) and a three-dimensional measurement state connected to the three-dimensional second transmitter (5b), and a third transmission circuit (26c) 3
A third open / close switch (switchable between a two-dimensional measurement state (open state) separated from the third dimension transmitter (3c) and a three-dimensional measurement state (closed state) connected to the three-dimensional third transmitter (3c) ( 30). The mode selection button (16) of the indicating member (8) is 2
When it is switched to the dimensional mode side, the mode switching device (22)
The switches (28) to (30) are switched to the two-dimensional measurement state, and the 25 kHz ultrasonic burst is transmitted from the two-dimensional first transmitter (3a) based on the transmission signal B1 from the first transmission circuit (26a). The (first ultrasonic burst) transmits a 40 kHz ultrasonic burst (second ultrasonic burst) from the two-dimensional second transmitter (3b) based on the transmission signal B2 from the second transmission circuit (26b). To be done. Conversely, when the mode selection button (16) of the indicating member (8) is switched to the three-dimensional mode side, the switches (28) to (30) of the mode switching device (22) are switched to the three-dimensional measurement state, Transmission signal B from the first transmission circuit (26a)
The first ultrasonic burst from the three-dimensional first transmitter (5a) based on 1 and the second ultrasonic burst from the three-dimensional second transmitter (5b) based on the transmission signal B2 from the second transmission circuit (26b). With respect to the ultrasonic burst, a 32 kHz ultrasonic burst (third ultrasonic burst) is transmitted from the three-dimensional third transmitter (5c) based on the transmission signal B3 from the third transmission circuit (26c).

The receiving device (24) has a microphone (1
The received signal E from 5) is passed through band filters (31a) (31b) (31c) having narrow band characteristics with different center frequencies from each other for each transmitter for the ultrasonic burst from each transmitter (3) (5). It is for detecting the received signal, and it has three receiving circuits (3
It is equipped with 2a) (32b) (32c). The receiving circuits are collectively denoted by reference numeral (32), and when it is necessary to distinguish them, the first receiving circuit (32a), the second receiving circuit (32b) and the third receiving circuit (32
c). Filters are also collectively referred to by the code (31),
When it is necessary to distinguish, the first filter (31
a), the second filter (31b) and the third filter (31c). The reception signal E from the microphone (15), the transmission start pulse signal A from the transmission control oscillation circuit (27), and the measurement start pulse signals C1 to C3 from the corresponding transmission circuits (26) are provided to the reception circuits (32). , And count control signals F1, F2, F3 are output from each receiving circuit (32) to the processing device (25). The center frequency of the first filter (31a) is 25 kHz
The first receiver circuit (32a) detects the first transmitter-specific reception signal for the first ultrasonic burst. Second filter (3
The center frequency of 1b) is 40 kHz, and the second receiving circuit (3
2b) detects the second transmitter-specific received signal for the second ultrasonic burst. The center frequency of the third filter (31c) is 32.
The third receiving circuit 32c detects the second transmitter-specific received signal for the second ultrasonic burst. The count control signals F1 to F3 from the respective receiving circuits (32) are turned on from the time when the corresponding measurement start pulse signals C1 to C3 are input until the time when the corresponding reception signal for each transmitter is detected, and other than that. Is off when.

The processing device (25) receives from each transmitter by the corresponding two-dimensional transmitter (3) or each three-dimensional transmitter (5) from the transmission start time of the ultrasonic burst by the receiving device (24). Based on the time elapsed until the signal detection time, the microphones (15) from the two-dimensional transmitters (3) or the three-dimensional transmitters (5)
It is for obtaining the distance to and the two-dimensional or three-dimensional position of the microphone (15), the counting device (33), 1MH
Oscillation circuit for counting z (34) and arithmetic unit for position measurement
It has (35). The counting device (33) includes three counters (36a) (36b) (36c). Counter sign (36)
, And when it is necessary to distinguish them, the first counter (36a), the second counter (36b), and the third counter, respectively.
I will call it (36c). The oscillator circuit (34) uses a clock pulse of 1 MHz for counting time for each counter.
It is for output to (36). For each counter (36),
Count control signals F1 to F from the corresponding receiving circuit (32)
3 and the reset signal G from the arithmetic unit (35) is input,
The count values H1, H2, H3 of each counter (36) are input to the arithmetic unit (35). The first counter (36a) starts the transmission of the first ultrasonic burst by the two-dimensional or three-dimensional first transmitters (3a) (5a), and then outputs the corresponding reception signal for each first transmitter. This is for counting the elapsed time until the detection by the first receiving circuit (32a). Second counter
(36b) is a 2D or 3D second transmitter (3b) (5b)
Is for counting the elapsed time from when the transmission of the second ultrasonic burst is started to when the second reception signal for each second transmitter is detected by the second reception circuit (32b). The third counter (36c) is a third three-dimensional transmitter (5
After the transmission of the third ultrasonic burst is started by c), the corresponding reception signal by the third transmitter is transmitted to the third reception circuit (32c).
It is for counting the elapsed time until it is detected by. Each counter (36) is reset by the reset signal G from the arithmetic unit (35) and counts the pulses from the oscillation circuit (34) while the corresponding count control signals F1 to F3 are on. , The time is counted, and the count values H1 to H3 when the counting is stopped are held.

The arithmetic unit (35) determines the distance from each two-dimensional transmitter (3) to the microphone (15) or each three-dimensional transmitter (15) based on the count values H1 to H3 of each counter (36). ) To the microphone (15), and the two-dimensional or three-dimensional position of the microphone (15) based on these distances. There is. In addition, the arithmetic unit (35)
Functionally, the AOC that controls the level of the transmission signal of the corresponding transmission circuit (26) according to the reception level of the reception signal for each transmitter
(Automatic output level control) means is provided. Arithmetic device (3
In 5), the propagation velocity of ultrasonic waves, position coordinate information of two 2D transmitters (3) in 2D coordinates on the screen (2), 3 3D coordinates in 3D coordinates in space Transmitter
Information necessary for position measurement, such as position coordinate information in (5), is set and stored. It should be noted that a temperature sensor may be provided at an appropriate location of the presentation device so that the set value of the ultrasonic wave propagation velocity is corrected according to the temperature change. The arithmetic unit (35) reads the count values H1 to H3 of each counter (36) each time the transmission start pulse signal A is input from the transmission control oscillation circuit (27), stores them, stores them, and stores each counter ( The reset signal G is output to 36). Then, until the next transmission start pulse signal A is input, each two-dimensional transmitter (3) or each three-dimensional transmitter is used based on the count values H1 to H3 of each counter (36) stored previously. Transmitter (5)
The distance from the microphone to the microphone (15) and the two-dimensional or three-dimensional position of the microphone (15) are calculated. Further, the arithmetic unit (35) is
Based on the distance from each transmitter (3) (5) to the microphone (15), the OC means transmits the transmission signal B to the transmitter (3) (5).
The transmission level values 1 to B3 are calculated and output to the corresponding transmission circuit (26) as transmission level control signals D1 to D3. The computing unit (35) has buttons (16) to (1
8) and the switch signal from the switch (19) are input, the switch signal information, the selection information of the measurement mode, the coordinate information of the measured two-dimensional position and three-dimensional position, etc.
It is output from the arithmetic unit (35) to the control unit (13).

The position measuring device (12) has the above structure.
Each time a transmission start pulse signal A is output from the transmission control oscillator circuit (27), the microphone of the microphone (15) is changed depending on the measurement mode.
Measure dimensional or three-dimensional position. Next, the position measurement operation by the position measurement device (12) will be described in detail for each measurement mode.

When the transmission control pulse signal A is output from the transmission control oscillation circuit (27) when the two-dimensional mode is selected, the arithmetic unit (35) first causes the first and second counters (36a) to operate. ) (36b) count values H1 and H2 are read and stored in a memory or the like, and then a reset signal G is output from the arithmetic unit (35) to reset each counter (36a) (36b). At the same time or slightly thereafter, the first and second ultrasonic bursts are transmitted from the two two-dimensional transmitters (3), respectively. At the same time as the start of transmission of each ultrasonic burst,
From the first and second transmission circuits (26a) (26b) to the first and second
Measurement start pulse signal C1 is applied to the receiving circuits (32a) and (32b), respectively.
, C2 are output, which causes the count control signal F1
, F2 is turned on and the first and second counters (36a)
(36b) starts counting. Then, until the next transmission start pulse signal A is output, the arithmetic circuit (35) calculates the two-dimensional position coordinates of the microphone (15) and transmits the transmission level control signals D1 and D2 as described later. Output is done. When the first ultrasonic burst transmitted from the two-dimensional first transmitter (3a) is received by the microphone (15) after the transmission of the first and second ultrasonic bursts is started, The received signal is detected by the first receiving circuit (32a), the count control signal F1 is turned off, and the first counter (36a)
Stops counting. At this time, the first counter (36a)
The count value H1 held at is the elapsed time from the transmission start time of the first ultrasonic burst to the detection time of the reception signal for each first transmitter, that is, from the two-dimensional first transmitter (3a) to the microphone ( It corresponds to the time required for ultrasonic waves to propagate up to 15). Similarly, the two-dimensional second transmitter (3
When the second ultrasonic burst from b) is received by the microphone (15), the received signal by the second transmitter is received by the second receiving circuit.
When detected by (32b), the count control signal F2 is turned off, and the second counter (36b) stops counting. At this time, the count value H2 held in the second counter (36b) is the elapsed time from the transmission start time of the second ultrasonic burst to the detection time of the reception signal by the second transmitter corresponding thereto, that is, the two-dimensional second count. 2 This corresponds to the time required for ultrasonic waves to propagate from the transmitter (3b) to the microphone (15). When the next transmission start pulse signal A is output, similarly to the above, the arithmetic unit (35) reads and stores the count values H1 and H2 and outputs the reset signal G. Then, the transmitting circuit (26a) (26b), the transmitter (3), the receiving circuit (32a) (3
In 2b) and the counters (36a) and (36b), the same operation as described above is performed. At the same time, in the arithmetic unit (35), the distances from the two two-dimensional transmitters (3) to the microphone (15) are respectively calculated based on the previously stored count values H1 and H2, and these distances are further calculated. Based on the above, the two-dimensional position coordinates of the microphone (15) on the screen (2) are calculated. As described above, the count value H1 of the first counter (36a) corresponds to the time required for ultrasonic waves to propagate from the two-dimensional first transmitter (3a) to the microphone (15). From the time and the propagation velocity of ultrasonic waves, the microphone from the two-dimensional first transmitter (3a)
The distance to (15) can be calculated. Similarly, the second counter (3
The distance from the two-dimensional second transmitter (3b) to the microphone (15) can be calculated from the count value H2 of 6b) and the propagation velocity of ultrasonic waves. Then, the two-dimensional position coordinates of the microphone (15) are calculated based on these distances and the two-dimensional position coordinate information of the two two-dimensional transmitters (3) set in the calculation device (35). You can On the other hand, in the AOC means of the arithmetic unit (35),
The transmission level value for the first transmission circuit (26a) is obtained based on the calculated value of the distance from the two-dimensional first transmitter (3a) to the microphone (15), which is the first transmission level control signal D1. It is output to the circuit (26a). This transmission level value is obtained by selecting a preset stepwise value so that it becomes larger as the calculated value of the distance becomes larger. Then, when the transmission start pulse signal A is output next and the transmission signal B1 is output from the first transmission circuit (26a), the level of the transmission signal B1 is adjusted based on the transmission level control signal D1. To be done. That is, the level of the transmission signal B1 is adjusted based on the calculated value of the distance with respect to the ultrasonic burst of the last two times. As a result, even if the distance from the transmitter (3a) to the microphone (15) changes, the reception level of the first transmitter-specific reception signal received by the reception circuit (32a) is kept within a certain range. Become. Similarly, the transmission level value for the second transmission circuit (26b) is obtained based on the calculated value of the distance from the two-dimensional second transmitter (3b) to the microphone (15), and this is used as the transmission level control signal D2. Based on the above transmission level control signal D2 when the transmission start pulse signal A is output next to the second transmission circuit (26b) and the transmission signal B2 is output from the second transmission circuit (26b). Thus, the level of the transmission signal B2 is adjusted. Then, by repeating the above operation,
Each time the transmission start pulse signal A is output, the microphone (15)
The two-dimensional position of is measured.

Even when the three-dimensional mode is selected, when the transmission start pulse signal A is output from the measurement control oscillation circuit (27), first, the arithmetic unit (35) causes the three counters to count.
After the count values H1 to H3 of (36) are read and stored, the reset signal G is output from the arithmetic unit (35) to reset each counter (36), and at the same time or slightly later, 3 The first, second and third ultrasonic bursts are transmitted from the three-dimensional transmitters (5). Simultaneously with the start of transmission of each ultrasonic burst, the measurement start pulse signals C1 and C from the three transmission circuits (26) to the three reception circuits (32), respectively.
2 and C3 are output, whereby the count control signal F
When 1, F2 and F3 are turned on, three counters (36) start counting. Then, until the next transmission start pulse signal A is output, the arithmetic unit (35) calculates the three-dimensional position coordinates of the microphone (15) and the transmission level control signals D1, D2, as described later. The output of D3 is performed. After the start of transmission of each ultrasonic burst, the first ultrasonic burst transmitted from the three-dimensional first transmitter (5a) is the microphone (15).
When the signal is received at, the first transmitter-specific reception signal is detected by the first reception circuit (32a), the count control signal F1 is turned off, and the first counter (36a) stops counting. Similarly, when the second ultrasonic burst transmitted from the three-dimensional second transmitter (5b) is received by the microphone (15),
The 2nd counter (36b) stops counting and the 3rd for 3D
The third ultrasonic burst transmitted from the transmitter (5c) is a microphone
When received at (15), the third counter (36c) stops counting. In this case as well, the count value H1 of the first counter (36a) is set to the second counter (36b) during the time required for the ultrasonic waves to propagate from the three-dimensional first transmitter (5a) to the microphone (15).
The count value H2 of the three-dimensional second transmitter (5b)
During the time required for the ultrasonic wave to propagate up to (15), the count value H3 of the third counter (36c) is set to the three-dimensional third transmitter (5c).
This corresponds to the time required for ultrasonic waves to propagate from the microphone to the microphone (15). When the next transmission start pulse signal A is output, the count values H1, H2, and H3 are read and stored by the arithmetic unit (35) and the reset signal G is output, as in the above. And the transmitter circuit (26), transmitter
(5) The receiving circuit (32) and the counter (36) perform the same operations as above. At the same time, in the arithmetic unit (35), based on the previously stored count values H1, H2, H3, from the three three-dimensional transmitters (5) to the microphone (15) as in the two-dimensional mode. The distances of are calculated respectively,
Furthermore, these distances and 3 are set in the arithmetic unit (35).
Based on the three-dimensional position coordinate information of each three-dimensional transmitter (5), the three-dimensional position coordinate of the microphone (15) is calculated. on the other hand,
In the AOC means of the arithmetic unit (35), as in the case of the two-dimensional measurement mode, three transmitting circuits (26) based on the calculated values of the distances from the three transmitters (5) to the microphone (15). To the corresponding transmission circuit (26) as transmission level control signals D1, D2 and D3. Then, by repeating the above operation,
Each time the transmission start pulse signal A is output, the microphone (15)
The three-dimensional position of is measured.

In the above presentation device,
As described above, the position measuring device (12) constantly measures the two-dimensional position or the three-dimensional position. That is, while the mode selection button (16) of the pointing member (8) is switched to the two-dimensional mode side, the two-dimensional position is measured,
While the two-dimensional position information is sent to the control device (13) and the mode selection button (16) is switched to the three-dimensional mode side, 3
The three-dimensional position information is measured and the three-dimensional position information is acquired by the control device.
Sent to (13). Then, the control device (13) controls the orientation adjustment device (7), the television camera (6) and the image display device (10) based on the position information, the switch signal information from the pointing member (8), and the like. By doing so, the image displayed on the screen (2) is controlled.

For example, the speaker selects the mode selection button (1
When the pointing member (8) is moved to an arbitrary position on the screen (2) while the 6) is switched to the two-dimensional side, the tip of the pointing member (8) at that time is the microphone (15) part. Screen (2)
The upper two-dimensional position is measured. Then, by combining such two-dimensional position measurement with various operation commands from the pointing member (8) using the up button (17) and the down button (18), for example, on the screen (2) Controls such as switching the display of, and selection of the work menu displayed on the screen (2) are performed. Also, by pressing the tip switch (19) of the pointing member (8) against the screen (2) to turn it on, the handwriting mode is set.
By pressing (19) on the screen (2) and moving it, handwriting input is performed by the pointing member (8), and thus the handwritten input information is displayed. Alternatively, for example, the handwriting input can be performed by moving the pointing member (8) while pressing the down button (18) (while keeping it on).

When the speaker moves the pointing member (8) to an arbitrary position in the space with the mode selection button (16) switched to the three-dimensional mode side, the pointing member at that time is moved.
The three-dimensional position of the tip of (8) is measured. Then, the measurement of such a three-dimensional position and the up button (17) and the down button
By combining various operation commands from the pointing member (8) using the (18), the TV camera (6) captures an image of an object such as a material and displays the image. For example, if the tip of the pointing member (8) is brought close to an object such as a material placed on the desk (9) at an arbitrary position, and an imaging command is issued, the control device (13) instructs Material (8)
The position of the tip of the object, that is, the three-dimensional position information of the object is stored, and the azimuth angle and elevation angle of the orientation adjustment device (7) are controlled based on this position information and the position information of the television camera (6), and the television is controlled. The camera (6) is aimed at the object, and the focus of the television camera (6) is adjusted to image the object. Then, based on the image signal from the television camera (6), the image of the captured object can be displayed on the screen (2).

When an image taken by the TV camera (6) is displayed on the screen (2), the image is moved, enlarged or reduced,
It may be required to perform image transformation such as rotation or projective transformation to make it easier to see, to combine with another image stored in advance, or to add a comment by handwriting input. Based on the selection of the measurement mode from (8) and various operation commands, the above-described operation can be performed by the image transformation means of the control device.

Next, with reference to FIGS. 16 and 17, an example of the operation of the indicating member (8) and the image transformation process in the case of enlargement / reduction, rotation, and projective transformation of the image transformation will be described in detail. .

16 (a), (b) and (c) are indicating members.
It is a figure for demonstrating the operating method of (8), and the imaging range of the television camera (6) is shown by the code | symbol T in each figure. The position in space is represented by three-dimensional Cartesian coordinates with the X axis, the Y axis, and the Z axis. In this case, the X axis and the Y axis are horizontal, and the Z axis is vertical.

When instructing the image transformation, first, referring to FIG.
As shown in (a), the center point P of the operation is set within the imaging range T of the television camera (6). This operation is performed by the pointing member (8)
This is performed by bringing the tip (the portion of the microphone (15)) of the above into the imaging range T and double-clicking the down button (18). When the lower button (18) is double-clicked while the tip of the pointing member (8) is within the imaging range T, the position of the tip of the pointing member (8) measured at that time is the center point P of the operation. Is set as. When the setting of the center point P of the operation is completed, the reference vector Vo is set as shown in FIG. 16 (b). This operation is performed by moving the tip of the indicating member (8) to a desired position in the space and then clicking the lower button (18). When the lower button (18) is clicked for the first time after setting the operation center point P, the operation center point P
To the position of the tip of the pointing member (8) measured at that time is determined, and this is set as the reference vector Vo. After setting the reference vector Vo,
As shown in FIG. 16 (c), the comparison vector Va is set. This operation is also performed by moving the tip of the indicating member (8) to a desired position in the space and then clicking the lower button (18). This operation can be repeated many times. When the lower button (18) is clicked for the second time after setting the operation center point P, the vector from the operation center point P to the position of the tip of the indicating member (8) measured at that time Is obtained, and this is set as the comparison vector Va at that time. Then, each time the comparison vector Va is set, the type of image deformation is determined based on the comparison vector Va, and the determined image processing is executed.

The image processing decision is made as follows by comparing the comparison vector Va with the reference vector Vo. That is, when the comparison vector Va is set,
First, the rotation angle θ of the comparison vector Vo and the comparison vector V
The rate of change ΔL in the length of a and the rate of change ΔZ in the Z coordinate of the comparison vector Va are obtained. The rotation angle θ is represented by the angle formed by the projection of the reference vector Vo on the XY plane with respect to the projection of the reference vector Vo on the XY plane. The rate of change .DELTA.L in length is represented by the ratio (La / Lo) between the length La of the comparison vector Va and the length Lo of the reference vector Vo. The change rate ΔZ of the Z coordinate is calculated by the comparison vector Va
Between the Z coordinate value Za of the tip (the end opposite to the center point P of the operation) and the Z coordinate value Zo of the tip of the reference vector Vo (Za-Zo), and the length Lo of the reference vector Vo. It is represented by the ratio ((Za-Zo) / Lo). In addition,
These values can be obtained using a well-known calculation formula.

Next, three amounts of the rotation angle θ, the length change rate ΔL and the Z coordinate change rate ΔZ are compared with appropriate weights, and when the rotation angle θ is the most dominant, the image rotation is performed. If the rate of change ΔL in length is also most dominant, the image is scaled up / down, and if the rate of change ΔZ in Z coordinate is most dominant, projective transformation of the image is performed.

17 (a), (b) and (c) show the setting operation of the central point P of the operation by the pointing member (8), the reference vector Vo and the comparison vector Va, and the corresponding image deformation. It is a figure which shows the relationship of. The left side of each drawing of FIG. 17 shows the operation of the pointing member (8), (a) and (b) are plan views of the part of the imaging range T, and (c) is a perspective view of the same part. There is. The right side of each drawing of FIG. 17 shows a state of image deformation on the screen (2), and is a view of the screen (2) viewed from the front. Further, in the case of FIG. 17, the reference vector Vo is set to be substantially parallel to the Y axis.

When instructing to rotate the image, for example, as shown in FIG.
The comparison vector Va is set as shown in 7 (a). In this case, the comparison vector Va is set so that its length does not change much from the reference vector Vo and is substantially horizontal. Therefore, the rotation angle θ becomes larger than the change rate ΔL of the length and the change rate ΔZ of the Z coordinate, the image is rotated, and the image on the screen (2) is changed from the state indicated by the broken line to the solid line. Change to the state shown. In this case, the direction and degree of rotation of the image are determined based on the direction and size of the rotation angle θ.

When instructing the enlargement / reduction of an image, the comparison vector Va is set, for example, as shown in FIG. 17 (b). In this case, the comparison vector Va is the reference vector Vo.
It is set in almost the same direction as. Therefore, compared with the rotation angle θ and the Z coordinate change rate ΔZ, the length change rate Δ
L becomes larger and the image is enlarged or reduced. In the case of the figure, the comparison vector Va is longer than the reference vector Vo,
Therefore, since the rate of change in length ΔL is greater than 1, the image is enlarged and the image on the screen (2) changes from the state shown by the broken line to the state shown by the solid line. When the comparison vector Va is shorter than the reference vector Vo, the length change rate ΔL becomes smaller than 1, and the image is reduced. In this case, the degree of image enlargement / reduction is determined based on the magnitude of the length change rate ΔL.

When instructing the projective transformation of an image, the comparison vector Va is set, for example, as shown in FIG. 17 (c). In this case, the comparison vector Va is the reference vector Vo.
And the length does not change much, and the reference vector Vo
It is set so that it is almost in the vertical plane including. Therefore, compared with the rotation angle θ and the rate of change ΔL of the length, Z
The change rate ΔZ of the coordinates increases, the projective transformation of the image is performed, and the image on the screen (2) changes from the state shown by the broken line to the state shown by the solid line. In this case, the direction and degree of the projective transformation of the image are determined based on the sign (direction) and the magnitude of the Z coordinate change rate ΔZ.

If the television camera is only aimed at the image pickup object, a light source is attached to the tip of the pointing member and the light source emits light when the light source emits light, in addition to the method described in the above embodiment. A possible method is to control the direction of the TV camera so that it comes to the center of the, and align the pin with the light source. However, with this method, the three-dimensional position of the light source cannot be accurately measured, and therefore it is not possible to issue an image deformation instruction using the above-mentioned instruction member. Also, the TV camera cannot be pointed in a direction that is not within the field of view of the TV camera.

An example of the configuration of the second receiving circuit (32b) is shown in FIG.
Is shown in. The receiving circuit (26b) is an amplifier circuit (37
b), bandpass filter (31b) having narrow band characteristic, half-wave rectifier circuit (38b), stepped envelope (envelope waveform) generation circuit (39b), shaping circuit (40b), comparator (41b), F / F It has a (flip-flop) (42b) and an ATLC circuit (automatic threshold adjustment circuit) (43b).

In the second receiving circuit (32b), the microphone (15)
The received signal E from is amplified by the amplifier circuit (37b) and input to the filter (31b). In the filter (31b), the second transmitter-specific reception signal I (see FIG. 9 (a)) for the second ultrasonic burst from the corresponding second transmitters (3b) and (5b) is extracted, and this is half-wave rectified. Input to circuit (38b). The half-wave rectification circuit (38b) half-wave rectifies the reception signal I for each second transmitter, and the envelope generation circuit (39b) produces a signal I
Stepped envelope J from half-wave rectified wave (see Fig. 11)
Is generated. The envelope generation circuit (39b) is well known as an AM wave detection circuit, and is composed of a capacitor (44) and a resistor (45). In a normal detection circuit, a smooth envelope that connects the peaks of the half-wave rectified wave is generated, but in this generation circuit (39b), the CR values of the capacitor (44) and resistor (45) are made smaller than usual. , The envelope rises in a stepwise manner. In the shaping circuit (40b), after the step-like envelope J is amplified by the amplifier circuit (46), low frequency components are removed by the high-pass filter (47), so that the step-like envelope K having a large difference between steps of the step. (See FIG. 12) is generated and this is the comparator
Input to one input terminal of (41b). The threshold value L from the ATLC circuit (43b) is input to the other input terminal of the comparator (41b), and the output signal of the comparator (41b) is input to the F / F (42b). In the comparator (41b), the step-like envelope K and the threshold value L are compared (see FIG. 13), and the envelope K
Is below the threshold L, the output signal of the comparator (41b) is off (Low level), and when the envelope K exceeds the threshold L, the output signal of the comparator (41b) is on. (H
high level).

The ATLC circuit (43b) adjusts the threshold value L according to the reception level of the signal I in order to improve the measurement accuracy.
A first analog switch for adjusting the
(48), first and second peak hold circuits (49) (50),
A second analog switch (51), a scale conversion circuit (52) and a switch control circuit (53) are provided. The transmission start pulse signal A from the transmission control oscillation circuit (27) is input to the switch control circuit (53), and each time the transmission start pulse signal A is input, the switch control circuit (53) causes two switches (4
8) (51) is interlocked to switch between the first state and the second state. In the first state, the first switch (48) is switched to the second peak hold circuit (50) side, and the envelope J
Is input to the second peak hold circuit (50),
The second switch (51) is switched to the first peak hold circuit (49) side, and the output of the first peak hold circuit (49) is input to the scale conversion circuit (52). On the contrary, in the second state, the first switch (48) causes the first peak hold circuit to operate.
Switched to the (49) side, the envelope J is input to the first peak hold circuit (49), and the second switch
(51) is switched to the second peak hold circuit (50) side, and the output of the second peak hold circuit (50) is input to the scale conversion circuit (52). The scale conversion circuit (52) has a second
Each peak hold circuit input via the switch (51)
(49) The magnitude of the threshold value L is adjusted according to the previous peak value of the envelope J held at (50). The threshold L is, for example, the previous envelope J
It is adjusted so as to have a constant ratio (for example, 1/5) with respect to the peak value of. When the transmission start pulse signal A is input to the switch control circuit (53) and the switches (48) and (51) are switched to the first state, when the reception signal E is input from the microphone (15) after this, the envelope J is the first switch (4
It is input to the second peak hold circuit (50) via 8) and the peak value is held. At this time, the peak value of the envelope J input after the previous input of the transmission start pulse signal A is held in the first peak hold circuit (49), and this is held via the second switch (51). It is input to the scale conversion circuit (52), and the threshold value L is adjusted based on this peak value. When the next transmission start pulse signal A is input to the switch control circuit (53) and the switches (48) and (51) are switched to the second state, when the reception signal E is input from the microphone (15) after this. , Envelope J is input to the first peak hold circuit (49) via the first switch (48), and the peak value is held. At this time, in the second peak hold circuit (50), as described above, the peak value of the envelope J input after the previous input of the transmission start pulse signal A is held, and this is held by the second switch ( It is input to the scale conversion circuit (52) via 51) and the threshold value L is adjusted based on this peak value. And
By repeating such an operation every time the transmission start pulse signal A is input, the previous transmission start pulse signal A
The threshold value L of this time is adjusted according to the peak value of the envelope J input after the input of.

The F / F (42b) is for outputting the count control signal F2 to the second counter (36b), and the measurement start pulse signal C2 from the second transmitting circuit (26b) is F / F (4
Enter it in 2b). The count control signal F2, which is the output of the F / F (42b), turns on when the measurement start pulse signal C2 is input, turns off when the output signal of the comparator (41b) turns on, and then , Is kept on until the measurement start pulse signal C2 is input.

In the second receiving circuit (32b), when the transmission start pulse signal A is input, the states of the switches (48) and (51) of the ATLC circuit (43b) are switched, whereby the scale converting circuit (52). Peak hold circuit connected to (49)
The threshold value L adjusted based on the previous peak value of the envelope J held at (50) is input to the comparator (41b). After this, the transmission signal B from the second transmission circuit (26b)
When 2 is output and the measurement start pulse signal C2 is output, the count control signal F2 from the F / F (42b) is turned on. Then, when the stepped envelope K for the second transmitter-specific received signal I extracted by the filter (31b) exceeds the threshold value L, this is detected by the comparator (41b), and the comparator (41b) The output signal of turns on and the F / F (42
The count control signal F2 from b) is turned off. That is, as described above, the count control signal F2 is turned on from when the measurement start pulse signal C2 is input until the second transmitter-specific reception signal I is detected.

Second filter in the second receiving circuit (32b)
An example of the structure of (31b) is shown in FIG. This filter (31b) is provided with a pair of piezoelectric ultrasonic transducers (55) (56) which are arranged opposite to each other in a cylindrical case (54). Each transducer (55) (56) has an elastic body (55
a) (56a), piezoelectric ceramics (55b) (56b), metal plate (55c) (5
6c) and a resonator (55d) (56d) is a known one, so that the resonators (55d) (56d) face each other, at the elastic body (55a) (56a) portion, the case ( It is fixed to support members (57) and (58) fixed to both ends of 54). The transducer (55) on the input side is connected to the input terminals (59a) and (59b), and the input terminals (59a) and (59b) are connected to the output terminal of the amplification circuit (37b). The transducer (56) on the output side is
The output terminals (60a) and (60b) are connected to the input terminals of the half-wave rectifier circuit (38b). The natural frequency of the two transducers (55) (56) is 40 kHz, and the mutual spacing of the resonators (55d) (56d) is the corresponding ultrasonic wave (40 kHz).
It is set to about 1 wavelength of z). This filter (31
The center frequency of b) is 40 kHz, and its cutoff characteristic (discrimination) is shown by the curve (b) in FIG. The transmission circuit (26
The degree of detuning of the transmission signal B2 of b) is determined based on the cutoff characteristic of the filter (31b).

The configurations of the first and third receiving circuits (32a) and (32c) are almost the same as that of the second receiving circuit (32b). First
In the receiving circuit (32a), the center frequency of the first filter (31a) is 25 kHz, and the F / F for outputting the count control signal F1 has a measurement start pulse signal C1 from the first transmitting circuit (26a). To enter. In the third receiving circuit (32c), the center frequency of the third filter (31c) is 32 kHz.
z / F / for outputting the count control signal F3
In F, the measurement start pulse signal C from the third transmission circuit (26c)
3 to enter. In FIG. 6, the cutoff characteristic of the first filter (31a) is shown by the code (a), and that of the third filter (31c) is shown by the code (c).

In the above-mentioned position measuring device, when two-dimensional or three-dimensional position measurement is carried out, conventionally, the frequencies of ultrasonic waves transmitted from a plurality of transmitters are the same.
However, in this case, if ultrasonic waves are transmitted from each transmitter at the same time, it is not possible to distinguish which transmitter the ultrasonic wave received by the receiver is from, so the ultrasonic wave transmission from each transmitter and the distance Was measured in a time-sharing manner. When measuring a two-dimensional position on a relatively small display screen, the number of transmitters is two, and since the ultrasonic wave propagation distance, that is, the propagation time is short, the distance from each transmitter can be measured in a time-division manner. Even if it goes, the measurement cycle is, for example, 10 mse
It can be a sufficiently short value of c or less. However,
When measuring a three-dimensional position in a relatively wide space, the number of transmitters is three, and the propagation time of ultrasonic waves is long, so if the distance from each transmitter is measured in time division, It becomes impossible to shorten the measurement cycle sufficiently. In the case of normal position measurement, it is not preferable that the measurement cycle be longer than 20 msec. For example, considering the measurement of a three-dimensional position in a space with one side of about 3 m, it takes 9 msec for an ultrasonic wave to propagate a distance of 3 m for one transmitter. Then, 27
Since it takes msec, the measurement cycle is 20 msec.
Cannot be less than

On the other hand, in the above position measuring device (12), ultrasonic waves having different frequencies are transmitted from the plurality of transmitters (3) and (5) almost at the same time, and the transmitters (3) and (5) are transmitted. From microphone (1
Since the distances up to 5) are measured almost at the same time, the measurement cycle can be shortened as compared with the case where the distances are measured in time division.

When three-dimensional position measurement is performed using ultrasonic waves, strong directivity of ultrasonic waves is not preferable. However, the directivity of ultrasonic waves becomes stronger as the frequency increases, and the frequency of ultrasonic waves that can be used for position measurement in a three-dimensional space becomes approximately 40 kHz or less. Also, if the frequency is set too low, it will be close to the audible band, and noise that is offensive to the ear may be generated or affected by the noise.
It is necessary to set the frequency to kHz or higher. Therefore, the frequencies of the ultrasonic waves that can be actually used by the three transmitters are relatively close to each other, for example, 40, 32, and 25 kHz. And, when using ultrasonic waves of such close frequencies, it is difficult to completely separate the ultrasonic waves of each frequency with a normal bandpass filter, and under the influence of other frequencies and external noise, There is a problem that the measurement accuracy decreases. Therefore, again, it is difficult to perform highly accurate position measurement in a relatively wide space with a relatively short measurement cycle.

On the other hand, in the above-mentioned position measuring device (12), the reception signal E of the microphone (15) is passed through a plurality of band-pass filters (36) having narrow band characteristics having different center frequencies, and each transmitter is transmitted. (3) Since the reception signal I for each transmitter for the ultrasonic waves from (5) is individually detected, even if ultrasonic waves with close frequencies are used, the influence of other ultrasonic waves and external noise Highly accurate measurement is possible because there is little reception. Furthermore, since each filter (36) has the above-described configuration, it has excellent blocking characteristics, is less affected by other ultrasonic waves and external noise, and enables more accurate measurement. .

Further, in the above position measuring device (12), the processing device (25) is provided with the AOC means and receives even if the position of the microphone (15) (distance from the transmitters (3), (5)) changes. The transmission signal B1 is based on the reception level so that the level falls within a certain range.
Since the level of .about.B3 is controlled, the cutoff property (S / N ratio) between the used frequencies is excellent in combination with the excellent cutoff characteristic of the filter (36) itself.

The reception level of ultrasonic waves is inversely proportional to the distance from the sound source. Therefore, assuming that the transmission level of the ultrasonic burst from each transmitter (3) (5) is always constant, the reception level changes when the distance from the corresponding transmitter (3) (5) changes. Further, when the position of the microphone (15) changes, a difference occurs between the reception levels of the ultrasonic bursts, and the difference becomes larger as the measurement range in space becomes wider. Further, in reality, the difference in the reception level is further increased due to the influence of the reflected wave and the influence of the angle between the transmitting surfaces of the transmitters (3) and (5) and the receiving surface of the microphone (15). Therefore, the filter (36) is required to have a cutoff characteristic as shown in FIG. That is, an attenuation rate of 1/10000 (-80 dB) or less is required near frequencies other than each other. On the other hand, in the case of the above embodiment, since the transmission level is controlled by the AOC means so that the reception level for each ultrasonic burst falls within a certain range, the cutoff characteristics required for the filter (36). Is as shown in FIG. That is, the attenuation rate in the vicinity of other frequencies is 1/500 or less. However, the cutoff characteristic as shown in FIG. 6 is also difficult to realize with a conventional bandpass filter using an electronic circuit, and can be realized by configuring the filter (36) as described above.

However, in applications where there is no problem even if the measurement cycle is long, it is possible to transmit ultrasonic waves of the same frequency from a plurality of transmitters and measure the distance from each transmitter in a time division manner. Good.

In the position measuring device as described above, in order to accurately measure the distance from the transmitter to the receiver (microphone), the ultrasonic burst transmission start time and the reception signal detection time corresponding thereto are accurately measured. Need to be determined. The transmission start time of the ultrasonic burst can be accurately determined in synchronization with the rising edge of the first pulse of the transmission signal. The envelope of the transmission signal is a square wave as shown in FIG. 8, but the envelope of the reception signal is sloped as shown in FIG. 9 (b) under the influence of the bandpass characteristics of the signal transmission line. Rise to. Therefore, it is difficult to accurately determine the detection time of the received signal. The detection of the received signal in the receiving circuit is conventionally performed as follows. That is, first, the received signal is half-wave rectified and the envelope of this half-wave rectified wave is taken. As shown in FIGS. 14 and 15, this envelope is a smooth one that connects the peaks of the half-wave rectified wave. Then, this envelope is compared with a predetermined threshold value, and when it exceeds the threshold value, it is determined that the received signal is detected.

However, the conventional measuring method as described above has the following problems.

First, as described above, the level of the received signal changes depending on the distance from the transmitter. When the ATLC circuit is not provided in the receiving circuit,
Since the received signal is always compared with a fixed threshold value, as shown in FIG. 14, when the received level of the received signal changes, a difference occurs between the detection points, and the difference in the time axis direction is measured. There will be an error. Therefore, an ATLC circuit is provided in the reception circuit, and the threshold value is adjusted based on the peak value of the previous reception signal so that the ratio of the threshold value to the peak value of the reception signal becomes constant. However, since the ATLC circuit uses the peak value of the previous reception signal as the estimated value of the peak value of the current reception signal, strictly speaking, the peak value of the previous reception signal and the peak value of the current reception wave are different. Therefore, the ratio of the threshold value to the peak value of the received signal is not constant, and as shown in FIG. 15, the fluctuation component in the time axis direction becomes a measurement error. This measurement error depends on the slope of the envelope, but since the conventional smooth envelope slope is gentle, the measurement error due to the variation of the threshold value becomes large.

On the other hand, in the above position measuring device (12), the level of the transmission signal is controlled by the AOC means so that the reception level of the reception signal falls within a certain range. The measurement error due to fluctuations in the reception level is small.

Further, in the above position measuring device (12), the receiving circuit (32) is provided with the ATLC circuit (43b), and in addition, the stepwise envelope is used for detecting the received signal. The stepped envelope is formed by the forming circuit (40b), the natural frequencies of the transmitters (3) and (5), and the center frequency of the filter (36), with respect to the transmission signal B1 to B1 of the transmission circuit (26). By detuning the frequency of B3 upward, the measurement accuracy is improved compared to the conventional one.

As is apparent from FIG. 11, when the step-like envelope is used, the rising slope of each step of the step becomes steeper as compared with the conventional smooth envelope slope. When the received signal is detected by comparing the envelope with the threshold value, the measurement error is determined by the slope of the envelope. Therefore, in the case of a staircase envelope, the measurement error is determined by the rising slope of each step of the staircase. For this reason, when the stepped envelope is used, the width of the measurement error is small and it is about 1/8 of the wavelength of the carrier.
About. In the case of 25kHz ultrasonic wave, the wavelength of the carrier wave is 14mm at room temperature, so the maximum measurement error is 2mm.
(± 1 mm). In the case of the above embodiment,
Further, since the step-like envelope is formed to increase the difference between the steps of the step as shown in FIG. 13,
The range of measurement error becomes smaller. When the frequency of the transmission signal is not detuned with respect to the frequencies of the transmitter and the filter, the reception signal becomes as shown in Fig. 9 (b). Taking the smooth envelope of the half-wave rectified wave, the solid line in Fig. 10 ( It becomes as shown in b). On the other hand, when the frequency of the transmission signal is detuned upward with respect to the frequencies of the transmitter and the filter, the reception signal becomes as shown in Fig. 9 (a), and its smooth envelope is shown by the broken line in Fig. 10. As shown in (a). As is clear from FIGS. 9 and 10, when the transmission signal is detuned, the waveform of the reception signal is distorted, but the slope of the envelope becomes larger than that when the transmission signal is not detuned. Therefore, even when the staircase-shaped envelope is taken, the rising slope of each step of the staircase is larger than that when the step is not detuned.
The range of measurement error becomes smaller. In this case,
Since it is only necessary to determine the point at which the received signal is detected, it is not necessary to faithfully reproduce the received signal with respect to the transmitted signal, and there is no problem even if distortion occurs in the received signal due to detuning.

In the conventional presentation device,
When a TV camera captures an image of a speaker or material and the image is displayed on the screen, the TV camera is fixed and the material that comes into the field of view is fixed. You can adjust the orientation, register several expected positions in advance, enter the registration number and direct the TV camera in that direction, or the TV automatically in the direction of the speaker's voice. A voice control system that points the camera is adopted. However, in the case of the fixed method, it is often difficult to bring the face of the speaker or the like into the visual field, and it is impossible to capture an image of a material or the like that is not in the visual field. Also,
In the case of the voice control system, the TV camera may face the wrong direction in response to noise such as the sound of flipping a note. Furthermore, in both the preset method and the voice control method, for example, when you want to display a material in a place that is not registered, such as on a desk, you cannot easily point the TV camera in that direction. It is necessary to move materials etc. into the field of view of the TV camera. Alternatively, it is necessary to manually point the television camera in a desired direction by using an operation means such as a joystick on the operation pad. However, in such a case, there is a problem in that the speaker cannot concentrate on the statement because of the operation, which distracts the audience. In addition, if the operation of the television camera or the like is left to another person, it becomes difficult to smoothly provide the material according to the progress of the topic.

On the other hand, in the above presentation device, the speaker simply moves the tip of the pointing member (8) near a material and operates the pointing member (8),
The television camera (6) can be pointed in that direction, which allows the material and the like to be imaged and displayed on the screen (2). Further, the position measuring device (12) is arranged on the screen (2) and in space, and the five transmitters (3) and (5) and the one microphone (15) attached to the indicating member (8). Since it is used to measure the position using ultrasonic waves, in order to measure the position on the screen (2) and in the space other than the transmitter (3) (5) and the microphone (15). The position can be measured relatively easily without the need for a special device.

In the above embodiment, the indicator member (8) is connected to the control unit (11) by the cable (20) to transmit the signal by wire, but this may be performed wirelessly. .

FIG. 18 shows an example of the configuration of the presentation device when the signal transmission is performed wirelessly.

In FIG. 18, two Fs are attached to the indicating member (8).
The M transmitters (64) and (65) are provided, and the position measuring device (12) is provided with two FM receivers (66) and (67). Then, the reception signal E from the microphone (15) is wirelessly transmitted from the transmitter (64) to the receiver (66), and further transmitted from the receiver (66) to the receiving device (24). Also, press buttons (16)-(18) and switch (1
The switch signal from 9) is wirelessly transmitted from the transmitter (65) to the receiver (66), and the mode switching device is further transmitted from the receiver (66).
(22) and the arithmetic circuit (32). Others are the same as the case of the above-mentioned embodiment, and the same portions are denoted by the same reference numerals.

When it is necessary to output the voice of the speaker through the speaker, a wired microphone device for voice or a wireless microphone device provided separately from the above presentation device can be used. In that case, a small microphone of the voice microphone device can be attached to an appropriate place such as the speaker's clothes.

As shown in FIG. 18, when a presentation device transmits a received signal from a microphone (15) wirelessly and a wireless microphone device for voice is used separately, the ultrasonic signal and the voice signal are transmitted. Since two channels are used, there is a possibility of crosstalk between the two channels within the usable bandwidth defined by the Radio Law.
This problem is solved by transmitting the ultrasonic signal and the audio signal in one channel.

FIG. 19 shows an example of the configuration of the presentation apparatus shown in FIG. 18, in which the ultrasonic signal and the audio signal are further transmitted by one channel.

In FIG. 19, a voice microphone (receiver) (68) is provided on the pointing member (8) side, in addition to the position measuring microphone (15). Further, a mixer (69) as a signal superimposing means is added to the indicating member (8). A microphone having a reception sensitivity limited to an audible band, such as a dynamic microphone, is used as the voice microphone (68). The voice microphone (68) may be attached to an appropriate place such as the base end side portion of the indicating member (8).
It may be provided separately from (8) and attached to the speaker's clothes or the like. On the other hand, on the control unit (11) side, an ultrasonic region frequency cutoff low-pass filter (61), an audio amplifier circuit (62) and a speaker (63) are added. In this case, the received signal from the microphone (15) is mainly the ultrasonic signal received from the ultrasonic burst from the transmitters (3) and (5), and the received signal from the microphone (68) is the speaker's voice. The received audio signal is in the audible band. Then, the mixer (69) superimposes the ultrasonic signal and the voice signal from the two microphones (15) and (68) and outputs the superposed signals, and this output is output from the FM transmitter (64) to the FM receiver (66). It is transmitted wirelessly. The reception signal E received by the receiver (66) is input to the low pass filter (61) in addition to the reception circuit (32). As described above, the received signal E is a superposition of the ultrasonic signal and the audio signal, but the audio signal in the audible band is separated from the received signal E by the low-pass filter (61), and this is amplified. Speaker (63) through circuit (62)
And the sound is played from the speaker (63). The audio signal output from the low-pass filter (61) is sent to the control device (13) and can be used for audio command, control and the like. In addition, by controlling the amplifier circuit (62) with the control device (13) in response to a command from the indicating member (8), it is possible to output sound from the speaker (63) or prevent it from being output. . Others are the same as in the case of the embodiment of FIG. 18, and the same parts are designated by the same reference numerals.

In the case of the embodiment shown in FIG. 19, only one occupied channel is required for transmitting the ultrasonic signal and the voice signal, and crosstalk does not occur. Further, since it is not necessary to separately prepare a wireless microphone device for voice, the cost can be reduced.

In the embodiment shown in FIG. 19, the signal transmission between the mixer (69) and the receiving circuit (32) and the low pass filter (61), and the buttons (16) to (18) and the switch are carried out.
The signal transmission between the device (19) and the mode switching device (22) and the arithmetic device (35) can of course be performed by wire. Also in this case, only one analog signal line for the acoustic signal of the ultrasonic signal and the sound signal is required.

In the embodiment shown in FIG. 19, a microphone for position measurement is used.
Although a microphone (68) for voice (15) and a voice (68) are separately provided, as shown in FIG. 20, one microphone (15) provided for the pointing member (8) is used for position measurement and voice. It can also be combined.

The presentation device shown in FIG.
The microphone (68) for sound and the mixer (69) are removed from the embodiment of FIG. In this case, the microphone of the indicating member (8)
(15) is a receiver that receives the ultrasonic waves from the transmitters (3) and (5),
It also serves as a voice receiver for receiving the voice of a speaker or the like, and a signal superimposing means for superimposing an ultrasonic signal and an audio signal. The reception signal E of the microphone (15) is superposed with the ultrasonic signal and the audio signal. It has been done. The reception signal E from the microphone (15) is wirelessly transmitted from the FM transmitter (64) to the FM receiver (66), and is transmitted from the receiver (66) to the receiving circuit (32) and the low pass filter (61). To be done. Others are the same as the case of the embodiment of FIG. 19, and the same portions are denoted by the same reference numerals.

In the case of the embodiment shown in FIG. 20, only one microphone for the ultrasonic signal and one for the audio signal are required, so that the cost can be further reduced.

In the above-mentioned embodiment, the position measuring device (12) measures both the three-dimensional position in the space and the two-dimensional position on the screen (2). It may not be necessary to measure the two-dimensional position.

FIG. 21 shows an example of the configuration of the presentation apparatus in the case where the part relating to the two-dimensional position measurement is removed from the embodiment shown in FIG.

In FIG. 21, the mode selection button (16) is removed from the pointing member (8). Also, a position measuring device
From (12) to two-dimensional transmitter (3) and mode switching device
(22) is removed and each transmission circuit (26) is always connected to the corresponding three-dimensional transmitter (5). Others are the same as the case of the embodiment of FIG. 19, and the same portions are denoted by the same reference numerals.

In the case of the embodiment of FIG. 21, the image display device (10)
May display an image on the screen (2) of the above embodiment. But in this case the screen (2)
Is used only for displaying images. Further, the image display device (10) may be one that displays an image on a TV, a liquid crystal display panel, or the like. When the image display device (10) uses a TV, the presentation can be used for a video conference. In that case, the image signal and the audio signal, from the control device (13) through an appropriate communication means,
Try to transmit to a TV installed in another place. The image display device (10) may display a three-dimensional image on a stereoscopic TV. In that case, for example, two TV cameras separated by the distance between the eyes of the human are used to capture images for the right eye and the left eye, and these images are used to display a three-dimensional image on a display screen on which a lenticular lens or the like is attached. Display the image.

In the embodiment shown in FIG. 21, the voice microphone (68) may be attached to the indicating member (8). Also, without separately providing a microphone (68) for voice, one microphone
In (15), both the ultrasonic wave and the voice may be used. Especially in the latter case, when the presentation is used in a karaoke studio, etc., when the singer sings with the pointing member (8), the TV camera (6) tracks this and the image display device such as TV ( The image of the singer is displayed on the display screen of (10), the image image of the song and the image of the singer are combined and displayed, or the singer operates the indicator member (8) to adjust the volume. Can be done.

Further, in the embodiment shown in FIG. 21, it is of course possible to transmit a signal between the pointing member (8) and the position measuring device (12) by wire.

The presentation device may be permanently installed in a conference room, an event hall, or the like, and may be used exclusively, or the entire presentation device may be portable and installed at a desired place for use. You may do it.

A mode switching button is used as the indicating member (8).
(16), the upper end button (17) and the lower end button (18) are provided on the base end portion, and the microphone (15) and the tip end portion (19) are provided on the end portion can be expanded and contracted. One can also be used.

[0088]

As described above, according to the method and apparatus of the present invention, the measurement cycle can be shortened as compared with the case where the distances from a plurality of transmitters are measured in a time division manner. Even if ultrasonic waves having frequencies close to each other are used, there is little influence of other ultrasonic waves or external noise, and highly accurate measurement is possible. Therefore, it is possible to accurately measure the position of a wide range in a short measurement cycle by using the method of mounting the receiver on the measured object.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a presentation device showing an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of the presentation device of FIG.

FIG. 3 is a side view showing an example of an indicating member.

FIG. 4 is a block diagram showing an example of a configuration of a second receiving circuit.

FIG. 5 is a vertical sectional view showing an example of a bandpass filter.

FIG. 6 is a graph showing a cutoff characteristic of a bandpass filter.

FIG. 7 is a graph showing a cutoff characteristic required for a bandpass filter when AOC means is not provided.

FIG. 8 is a timing chart showing an example of a transmission signal.

FIG. 9 is a timing chart showing transmitter-specific reception signals when a transmission signal is detuned and when it is not detuned.

FIG. 10 is a timing chart showing a smooth envelope of a half-wave rectified wave of a reception signal for each transmitter when a transmission signal is detuned and when the transmission signal is not detuned.

FIG. 11 is a timing chart showing a stepped envelope of a half-wave rectified wave of a reception signal for each transmitter.

FIG. 12 is a timing chart showing a stepped envelope and a stepped envelope in which the difference between steps is increased.

FIG. 13 is a timing chart showing a relationship between a step-like envelope having a large disparity between steps and a threshold value.

FIG. 14 is a timing chart showing a relationship between a smooth envelope and a threshold when reception levels of received signals are different.

FIG. 15 is a timing chart showing a relationship between a smooth envelope of a received signal and a change in threshold value.

FIG. 16 is an explanatory diagram showing a method of operating an instruction member when instructing a graphic transformation.

FIG. 17 is an explanatory diagram showing the relationship between the operation of the pointing member and the graphic deformation.

FIG. 18 is a block diagram corresponding to FIG. 2 showing another embodiment of the present invention.

FIG. 19 is a block diagram corresponding to FIG. 2 showing still another embodiment of the present invention.

FIG. 20 is a block diagram corresponding to FIG. 2 showing still another embodiment of the present invention.

FIG. 21 is a block diagram corresponding to FIG. 2 showing still another embodiment of the present invention.

[Explanation of symbols]

 (3a) (3b) Transmitter for two-dimensional measurement (5a) (5b) (5c) Transmitter for three-dimensional measurement (8) Pointing member (12) Position measuring device (15) Microphone (receiver) (23) Transmission Device (24) Receiver (25) Processor (31a) (31b) (31c) Band-pass filter (55) (56) Piezoelectric ultrasonic transducer (55d) (56d) Resonator

Claims (3)

[Claims] 1. Ultrasonic waves having different frequencies are intermittently and substantially simultaneously transmitted from a plurality of transmitters arranged at predetermined intervals, and these ultrasonic waves are attached to an object to be measured.
Received by one receiver, the received signal of the receiver is passed through a band-pass filter having a plurality of narrow band characteristics having different center frequencies from each other, and the received signal for each ultrasonic wave from each transmitter is individually detected, Obtain the distance from each transmitter to the receiver based on the elapsed time from the transmission start time of the ultrasonic wave by each transmitter to the detection time of the corresponding reception signal for each transmitter,
A position measuring method characterized in that the position of an object to be measured is obtained based on these distances. 2. Ultrasonic waves having different frequencies are intermittently and substantially simultaneously transmitted from a plurality of transmitters arranged at a predetermined interval, one receiver attached to an object to be measured, and each transmitter. Transmitting device, receiving device for individually detecting the received signal of each transmitter for ultrasonic waves from each transmitter by passing the received signal of the receiver through a band-pass filter having a plurality of narrow band characteristics having different center frequencies, and each transmission A processing device that determines the distance from each transmitter to the receiver and the position of the measured object based on the elapsed time from the start time of ultrasonic wave transmission by the detector to the detection time of the corresponding reception signal for each transmitter Position measuring device characterized by. 3. A band-pass filter comprises two piezoelectric ultrasonic transducers having the same frequency as a corresponding ultrasonic wave, and the resonators of these ultrasonic transducers are opposed to each other with a distance of about one wavelength of the corresponding ultrasonic wave. 3. The position measuring device according to claim 2, wherein an input signal is applied to an electrode of one transducer and an output signal is taken out from an electrode of the other transducer.