KR20030081582A - Ultrasonic coordinates measurement device and method - Google Patents

Abstract

PURPOSE: An apparatus and a method for measuring position coordinates of an ultrasonic wave are provided to maintain superior resolution of the position coordinate measuring apparatus even if the apparatus is used in a large region. CONSTITUTION: A position coordinate measuring apparatus for an ultrasonic wave includes a pointer(20) for radiating predetermined frequencies. At least one ultrasonic wave receiving section is provided in a two-dimensional plane to detect the movement of the pointer. A position coordinate measuring section is provided to calculate a position coordinate of the ultrasonic wave. The position coordinate measuring section has a time information detecting part(40) for detecting position information of each ultrasonic wave receiving section using a timer and a position coordinate calculating par(35)t for calculating the position coordinate of the pointer based on information detected by the time information detecting part(40).

Description

Ultrasonic coordinates measurement device and method

The present invention relates to an apparatus for measuring the position coordinates of a pointer by receiving an ultrasonic wave radiated from a pointer moving in a two-dimensional plane, and more particularly, by detecting an ultrasonic pointer and moving the pointer on a wide board on a two-dimensional plane. The present invention relates to an ultrasonic position coordinate measuring apparatus and method for calculating a position coordinate value of a pointer through a position coordinate calculating unit and outputting the same in various forms through a PC or a corresponding means.

A coordinate measurement algorithm for detecting the position coordinate of the ultrasonic radiation pointer on the existing two-dimensional plane is described with reference to FIG.

As shown in FIG. 1, a phase difference occurs according to a difference in ultrasonic arrival times between two ultrasonic receivers S10 and S11 among three ultrasonic receivers S10, S11, and S01, which are ultrasonic receivers 10 that detect ultrasonic waves radiated from a pointer. Then, the relative distance difference from P (x, y) can be obtained. Therefore, one hyperbola A can be obtained from the distance between the ultrasonic receivers S10 and S11 and the distance difference between P (x, y). In addition, another hyperbola B is generated by the distance difference between the positions of the ultrasonic receivers S11 and S01 and P (x, y). As such, the two hyperbolas have one intersection within the confined area 100 of the board or blackboard, which is the coordinate at which the ultrasound is emitted.

However, the conventional ultrasonic position coordinate measuring algorithm as described above is a technique for measuring coordinates using only the phase difference of ultrasonic waves. As the area 100 increases, the farther the ultrasonic distance is, the signal-to-noise ratio decreases, so that it is difficult to measure accurate phase difference. It has a hard disadvantage. Therefore, in the area such as a wide board such as a school blackboard, the error of the measured position coordinate value increases, which causes a problem of a sharp drop in resolution.

In general, the ultrasonic frequency region for the coordinate measuring system measured in the region of 2m to 3m of the various ultrasonic region mainly uses ultrasonic waves in the 40KHz band. This is because ultrasonic waves of higher frequencies are not able to secure a sufficient signal-to-noise ratio (SNR) due to the rapid decrease in output depending on the transmission distance. Ultrasonic waves of lower frequencies are considerably degraded due to their longer wavelengths. Because there is. Therefore, in such applications, the most commonly used ultrasonic frequency at present is 40 KHz. However, this frequency domain also has a limitation in constructing a coordinate measuring system having a wide range of 3m or more due to the limitation of its measuring distance.

Accordingly, an object of the present invention is to supplement the problems of the conventional ultrasonic position coordinate measuring technique effective only in the relatively small region as described above, and the position coordinate measuring apparatus that can maintain the resolution even in an infinite size region such as a wide board. And at this time, to provide an ultrasonic position coordinate measuring apparatus and method having an algorithm for minimizing the number of the ultrasonic receiver is inevitably added.

1 is a configuration diagram of a conventional ultrasonic position coordinate measuring algorithm.

2A is a block diagram for explaining a restricted area and an extended area of the present invention;

Figure 2b is a pointer diagram of the present invention.

3 is a configuration diagram of the ultrasonic receiver and the position coordinate calculation unit of the present invention.

4 is a block diagram of an ultrasonic position coordinate measuring apparatus according to the present invention.

5 is a signal flow diagram of the ultrasonic position coordinate measuring apparatus according to the present invention.

Figure 6 is a model diagram for explaining the ultrasonic position coordinate measurement algorithm of the present invention.

Figure 7 is a model diagram for explaining and expanding the measurement algorithm of the present invention.

<Description of Drawing>

Ultrasonic receiver 10, ultrasonic sensors 23 and 11 for transmission and reception, signal detector 13, pointer (ultrasound transmitter 20), housing 21, ink marker 22, ultrasonic drive circuit 24, A power supply controller 25, a power supply 26, a marker tip 27, a board 30, a position coordinate calculator 35, a time information detector 40, a signal processor 42, a signal converter 43, Timer 44, operation controller 50, position calculator 52, storage 53, central processor 54, display 60, user interface 70, area 100, wide board 100 ')

Prerequisites

The meanings of the restricted area and the extended area according to the present invention will be described with reference to FIG. 2A.

As shown in Fig. 2A, the limited area means a limited area of about 2 to 3 m that can secure a constant resolution by a conventional position coordinate measuring method. On the other hand, the extended area is an area in which the position of the pointer can be measured without sacrificing the resolution by the position coordinate measuring algorithm of the present invention, and means an extended area in the limited area.

Ultrasonic Position Coordinate Measuring System

The overall system of the present invention is an ultrasonic position coordinate measuring apparatus comprising a pointer (ultrasound transmitting unit), an ultrasonic receiving unit, a position coordinate calculating unit consisting of a time information detecting unit and an operation control unit, which will be described with reference to the drawings. .

First, a pointer for transmitting ultrasonic waves will be described. As shown in FIG. 2B, the pointer (ultrasound transmitting unit) 20 used in the present invention is implemented in the form including the ink marker 22, and the power supply unit 26 for supplying power to the pointer 20 and the The ultrasonic driving circuit unit 24, which receives the power from the power supply unit 26 and generates ultrasonic waves at an arbitrary time and frequency, senses contact between the pointer 20 and the board and turns on the pointer 20. Or, the power control unit 25 for controlling the power operation of the off (off) is configured in the housing 21, the ultrasonic signal generated from the ultrasonic drive circuit unit 24 in accordance with the operation of the power control unit 25 is transmitted It is radiated through the credit ultrasonic sensor 23.

In the pointer 20 of the present invention configured as described above, a battery generally used is used as the power source used, and a switch or the like may be used as the power control unit 25 that controls the power operation (on / off). However, the present invention is not limited thereto. In addition, the function of the ultrasonic driving circuit unit 24 for generating ultrasonic waves at any time and frequency not described is as known to those skilled in the art.

Looking at the operation of the pointer configured as described above, when the marker tip 27 of the pointer 20 is in contact with the board (board), the switch of the power control unit 25 is turned on (on). At this time, the ultrasonic signal generated from the ultrasonic driving circuit unit 24 that receives the power from the power supply unit 26 to generate ultrasonic waves at an arbitrary time and frequency is radiated 360 ° through the transmitting ultrasonic sensor 23.

Next, the present invention will be described with reference to the accompanying drawings an ultrasound receiver for receiving an ultrasound radiated from a pointer (ultrasound transmitter) and a position coordinate calculator for calculating a position coordinate of a pointer detected through the ultrasound receiver.

As shown in Figures 3 and 4, at least one ultrasonic receiver 10 attached to the outer periphery of the wide board 30 on the two-dimensional plane at arbitrary intervals to detect the movement of the pointer is an ultrasonic signal transmitted from the pointer It includes a receiving ultrasonic sensor 11 for receiving a signal and a signal detection unit (Detector Circuit, 13) for detecting the signal through the receiving ultrasonic sensor 11, including an amplifier and a comparator (not shown).

The configuration of the position coordinate calculator for calculating the position coordinates of the pointers detected by the one or more ultrasonic receivers 10 is as follows.

The position coordinate calculating unit 35 is largely comprised of a time information detecting unit 40 and an operation control unit 50. First, the signal processor 42 of the time information detector 40 finds three ultrasonic receivers 10 that are closest to the ultrasonic sensor for transmitting a pointer among the ultrasonic receivers 10 and performs signal processing such as noise reduction. . Next, the absolute time information received by the ultrasonic signal receiving unit 10 is detected by a system-specific timer (timer, 44) and temporarily stored in a register (not shown), and obtained through the timer 44 The ultrasonic receiving absolute time data and the position information of the ultrasonic receiving unit input in advance are converted into signals in accordance with a communication protocol by the signal conversion unit 43 and then transmitted to the operation control unit 50.

The position calculator 52 of the operation controller 50 receiving the data (the ultrasonic receiver position information and the ultrasonic reception absolute time) from the time information detector 40 calculates the position coordinates of the pointer, and the calculated data is used by the user. Depending on the control of the interface (User Interface, 70) is also stored in the storage unit 53, and output in various forms (display, 60) through a PC or a corresponding means (not shown). This operation is controlled by the central processing unit 54 of the operation control unit 50, the operation control unit 50 according to the present invention can be processed by software using a PC or other corresponding processor unit (unit).

And, the data transmitted from the time information detecting unit 40 to the operation control unit 50 is transmitted according to the communication protocol, in the present invention according to the communication protocol in the form of {ultrasound receiver sensor position information, ultrasonic reception absolute time} Is sent.

According to the present invention configured as described above, the position coordinate value of the pointer calculated by the operation control unit is output (60) in various forms through a PC or a corresponding means according to the user interface 70.

The technical idea according to the present invention will be described with reference to Fig. 4, which is a system for obtaining the position coordinates of a pointer on a limited area.

As shown in FIG. 4, when the pointer 20 detects contact with the board 30 and emits ultrasonic waves at an arbitrary frequency, one or more ultrasonic receivers attached to the outside of the board 30 at arbitrary intervals ( 10) That is, the ultrasonic signals are received (detected) in S00, S10, S20, S01, S11, and S21. Then, the ultrasonic sensor for transmission of the pointer 20 among the one or more ultrasonic receivers 10 receiving the ultrasonic signal radiated from the pointer 20 in the signal processing unit (FIGS. 3 and 42) of the time information sensor 40. The three ultrasonic receivers 10 (ie, S10, S11, S20 in the drawing) at the shortest distance are found. Then, after detecting the absolute time information received by the ultrasonic signal radiated from the pointer 20 through the sensor position information and the timer (Figs. 3, 44) of each selected ultrasonic receiver, the signal converter 43 meets the communication protocol. The conversion is transmitted to the operation control unit 50. In the operation control unit 50 receiving the data, the position coordinates of the pointer are calculated by the position calculating unit 52 under the control of the central processing unit 54 shown in FIG. 3, which is stored in the storage unit 53 or the user. Depending on the interface 70, the output 60 is output in various forms via a PC or equivalent means (not shown). Here, the signal from the operation control unit 50 is transmitted to a PC or a corresponding means by a USB (Universal Serial Bus) communication means.

Such a signal flow centering on the operation of the ultrasonic position coordinate measuring apparatus in the limited region described with reference to FIG. 4 is shown in FIG. 5. For reference, the signal flow diagram shown in FIG. 5 is an output flow diagram of a signal transmitted from the signal converter 43 of the time information sensor 40 of FIG. 3 to the position calculator 52 of the operation controller 50.

As shown in FIG. 5, the signals of three ultrasonic receivers that receive the ultrasonic signals radiated from the ultrasonic sensor for transmitting the pointer, that is, the signals L10, L11, and L20 in the fast order of time are {ultrasound receiver sensor position information and ultrasonic reception]. Absolute time} is transmitted according to communication protocol. That is, as shown in the figure, the first signal L10 is transmitted in the form of {S10, T10}, L11 in the form of (S11, T11), L20 is transmitted in the form of {S20, T20}. However, in the present invention, in order to obtain more improved resolution, the fourth sensor signal L21, that is, {S21, T21} is additionally available information.

Ultrasonic Position Coordinate Measuring Method

An ultrasonic position coordinate measuring method according to the present invention, which receives ultrasonic waves emitted from a moving pointer on a wide board on a two-dimensional plane and calculates position coordinates of the pointers detected by the ultrasonic receiver, will be described with reference to the accompanying drawings. Explain.

The method (algorithm) for measuring the ultrasonic position coordinates used in the present invention includes the position coordinates calculated in the limited region based on any number of ultrasonic receivers closest to the position from which the ultrasonic waves are radiated. This method converts the coordinates into reference coordinates and calculates the position coordinates in the entire system. With reference to the drawings, the algorithm for obtaining the position coordinates of the pointer on the extended wide board will be described, starting with the description of the algorithm for measuring the position coordinates of the pointer in the restricted area.

First, the algorithm for measuring the ultrasonic position coordinates in the limited area will be described with reference to FIG. As shown in the figure, the algorithm of the present invention will be described taking the coordinate calculation method of P1 (x, y) as an example.

In the drawing, a process of obtaining coordinates of P1 (x, y) by using four groups of ultrasonic receivers 10 consisting of S10, S00, S01, and S11 in the limited area 100 is as follows.

First, P1 (x1, y1) is obtained from three groups of ultrasonic receivers 10 of S10, S00, and S01, and coordinates of P1 (x2, y2) of three groups of ultrasonic receivers 10 of S10, S11, and S01 are obtained. Obtain The final P1 (x, y) is calculated by weighted sum of P1 (x1, y1) and P1 (x2, y2) coordinates obtained above.

First, the system of equation (1) must be solved to find P1 (x1, y1).

(2)

(3)

here, ,

In [Equation 1] above, Is the coordinate value of the receiver sensor S (N, M), Is the absolute time that the S (N, M) sensor received the ultrasonic pulse.

Solving the system of equations (1), we get two (x, y), where If you choose to be expressed as one equation [Equation 2].

here,

On the other hand, in order to find P1 (x2, y2), it is necessary to solve the simultaneous equations of [Equation 3] as shown in [Equation 1].

(2)

(3)

here, ,

In the above Equation 3, since the linear receiving units S10, S11 and S11, S01 are perpendicular to each other, the following Equation 4 is established.

Therefore, in [Equation 3] silver Changes to

And similarly to P1 (x1, y1), P1 (x2, y2) Considering the case, can be expressed by one equation as shown in [Equation 5].

here,

Now, by weighted sum of P1 (x1, y1) and P1 (x2, y2), the final P1 (x, y) can be obtained. In the present invention, a weight for obtaining an improved resolution may be obtained from Equation 6 below.

[Equation 6] is configured to give a greater weight to P1 (x1, y1) closer to S00, and to give a greater weight to P1 (x2, y2) closer to S11. As a result of weight addition, P1 (x, y) according to the present invention is as follows.

,

According to the present invention, the algorithm for obtaining the position coordinates of the pointer in the restricted area is as described above. Here, the expansion algorithm of the present invention will be described taking an example of a wide board 100 'having an ultrasonic sensor installed in two rows and N columns shown in FIG.

As shown in Fig. 7, the calculation method of P2 (x, y) is in the direction of increasing the reference coordinate axis to the right, that is, x You can think of it as parallel. Therefore, the parallel coordinates P2 (x, y) can be calculated as in Equation (8).

That is, [Equation 1] to [Equation 7] After entering the corrected value in, calculate (x, y) and finally the x coordinate It only needs to be moved parallel to the left, that is, in the direction of decreasing x.

In this way, the equation expanded in the case of PN (x, y) is shown in [Equation 9].

As described above, according to the algorithm for obtaining the position coordinates of the pointer in the wide board on the two-dimensional plane of the present invention, the calculation of the position coordinate value of the pointer is based on the limited number of ultrasonic receivers closest to the position where the ultrasonic wave is emitted. The position coordinates calculated at are converted into the reference coordinates of the entire area including the extended area and calculated as the position coordinates on the whole system. As described above, according to the algorithm of the present invention, the positional coordinates of the pointer can be obtained without sacrificing the resolution on the wide board where the rows and columns are infinitely extended.

As described above, according to the ultrasonic position coordinate measuring apparatus and method of the present invention, the resolution of the existing ultrasonic position coordinate measuring technology effective only in a relatively small area can be maintained in the infinite size region, at this time, Inevitably, the number of ultrasonic receivers added is minimized. This may be used for industrial devices, medical devices, toys, robot fields, online lectures, etc., where work is performed using two-dimensional coordinates.

Claims (9)

In the wide board having the restricted area and the extended area on the 2D plane, the pointer moving in the extended area is detected by the ultrasonic receiver, and the position coordinate value of the changed pointer is calculated by the position coordinate calculating unit, and this is obtained through a PC or a corresponding means. As a device for outputting in various forms, Implemented in the form including an ink marker, a pointer (ultrasound transmitting unit) that emits a predetermined frequency, One or more ultrasonic receivers attached to M-rows and N-columns at arbitrary intervals outside the wide board on a two-dimensional plane to detect the movement of the pointer; A time information sensing unit for finding three ultrasonic receivers closest to the ultrasonic transmitter for transmitting the pointer among the ultrasonic receivers, and detecting time information of the ultrasonic receiver and position information of each ultrasonic receiver with a system-specific timer; Comprising a calculation control unit for calculating the position coordinates of the pointer using the information detected by the time information detecting unit is composed of a position coordinate calculation unit for calculating the position coordinates of the pointer detected by the ultrasonic receiver, Ultrasonic position coordinate measuring apparatus characterized in that the position coordinate value of the pointer calculated by the calculation control unit of the position coordinate calculator is output (displayed) in various forms through a PC or a corresponding means according to the user environment (interface). . The ultrasonic position coordinate measuring apparatus according to claim 1, wherein M = 2. The method of claim 1, wherein the time information detecting unit A signal processor for selecting three ultrasonic signals which are fast in time among the input ultrasonic signals and removing noise of the signal; A timer generally used in a system for obtaining an absolute time of reception of an ultrasonic signal obtained by the signal processor; Ultrasonic position coordinate measurement, characterized in that consisting of a signal conversion unit for converting the received absolute time data of the ultrasonic signal obtained through the timer to match the communication protocol (protocol) for transmission together with the position information of the ultrasonic receiver input in advance Device. The ultrasonic position coordinate measuring apparatus according to claim 1 or 3, wherein the time information detecting unit can further use information of a fourth ultrasonic signal among the input ultrasonic signals in order to obtain more improved resolution. The method of claim 1, wherein the operation control unit A position calculator for calculating a position coordinate value of the pointer using data received from the time information detector; A storage unit for storing the position coordinate values of the pointer calculated through the position calculator; And a central processing unit for controlling the position calculating unit and the storage unit, wherein the arithmetic control unit is capable of processing by software using a PC or another processor unit corresponding thereto. The communication protocol according to any one of claims 1, 3, and 5, wherein the communication protocol for transmission from the time information sensing unit to the operation control unit follows the form of {ultrasound receiver sensor position information, ultrasonic reception absolute time}. Ultrasonic position coordinate measuring device. As a position coordinate calculation method of a position coordinate measuring apparatus configured and operated as described in claim 1, In the direction in which x increases from an arbitrary position P1 (x, y) of the restricted area of the wide board where the ultrasonic receiver is installed in M rows and N columns on the outside. The coordinate P2 (x, y) located in the extended area by Obtaining P1 (x1, y1) using three groups of first ultrasonic receivers among the ultrasonic receivers located in the restricted region; Obtaining P1 (x2, y2) using three second ultrasonic receiver groups among ultrasonic receivers located in the restricted region; Weighting P1 (x1, y1) and P1 (x2, y2) to obtain pointer position coordinates P1 (x, y) of the restricted area; The reference coordinate axis of P2 (x, y) is from P1 (x, y). Since x is moved in parallel, x is equal to x in the stepwise formula for obtaining P1 (x, y). Calculate the (x, y) by putting the translational value by The x coordinate calculated above And obtaining a position coordinate P2 (x, y) through a step of moving in a direction in which x decreases as much as possible. The method of claim 7, wherein the equation for obtaining any position PN (x, y) of the extended region is Ultrasonic position coordinate measurement method, characterized in that generalized by the same algorithm. The method of claim 8, wherein the weight in obtaining the position coordinates of the pointer is Ultrasonic position coordinate measuring method characterized in that.