JPH0347531B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position correction method for a coordinate input device.

When a pattern such as a character or figure input from the input surface of a coordinate input device is sent to an output device for reproduction and output, position correction is performed to obtain the output pattern at a desired position and size.

FIG. 1 is a block diagram for explaining a position correction method for a coordinate input device. The coordinate input device 1 is
An electric signal (coordinate signal) indicating the coordinates of the handwritten input location is generated in accordance with a pattern handwritten on the input surface 10 with the pen 11 and sent to the control device 3 . The control device 3 converts the coordinate signal into an image signal, sends this to the image display device 2, and displays an image of the input pattern on the display surface 20. In this case, the coordinate signal generated when inputting to the origin Oi (or full-scale point Fi) on the input surface 10 and the coordinate signal to be displayed at the origin Od (or full-scale point Fd) on the display surface 20 are usually used. Since this is different from the signal, it is necessary to correct the position so that they match.

In the conventional position correction method for a coordinate input device, this position correction is performed by a processor built in the control device 3. At the time of initial calibration, after specifying the initial calibration mode by operating a switch (not shown) or the like, input is first made to the origin Oi of the input surface 10 with the pen 11 as shown by the broken arrow A. The processor in the control device 3 compares the digital coordinate signal sent at this time with the digital coordinate signal for displaying the origin Od of the display surface 20, and generates a digital offset signal indicating the difference between the two. generated and stored in memory. Next, add (or subtract) the digital offset signal to the digital coordinate signal sent when inputting to the full-scale point Fi on the input surface 10 with the pen 11, and add (or subtract) the digital offset signal to this and the full-scale point Fd on the display surface 20. A digital coefficient signal indicating the ratio to the digital coordinate signal for displaying is generated and stored in memory. When specifying the input mode, the processor in the control device 3 first adds (or subtracts) the digital offset signal read from the memory to the digital coordinate signal sent in response to the input to the input surface 10, and then adds (or subtracts) the digital offset signal read from the memory. The addition (or subtraction) result is multiplied by a digital coefficient signal to create a position-corrected digital coordinate signal. The control device 3 converts this position-corrected coordinate signal into an image signal and sends it to the image display device 2. By performing the position correction in this way, for example, the cursor C can be displayed on the display surface 20.
When inputting to the origin Oi, the cursor display C moves to the origin Od as shown by the dashed arrow B, and when inputting to the full-scale point Fi, the cursor C moves to the full-scale point Fd. , and the output pattern is displayed in the desired position and size.

However, in such a conventional position correction method for a coordinate input device, the processing speed is slow because the position correction is performed by arithmetic processing in the processor in the control device 3, and the digital offset signal and coefficient signal are Since it is stored in the memory within the control device 3, when a plurality of coordinate input devices 1 are connected to the control device 3, memory capacity corresponding to the number of coordinate input devices 1 is required, and there is a drawback that there is a limit to the number of devices that can be connected. .

An object of the present invention is to provide a position correction method for a coordinate input device that eliminates the above-mentioned drawbacks, has a high processing speed, and does not impose a limit on the number of input devices that can be connected to a control device.

The method of the present invention includes a first variable means for varying the voltage of a first electrical signal indicating the shift amount of the origin at the time of origin calibration, and shifting the voltage of the received signal by the voltage of the first electrical signal. an origin correction circuit having an addition circuit for transmitting, a second variable means for varying a coefficient indicating an expansion rate of coordinates during full scale calibration, and a coefficient circuit for multiplying the voltage of a received signal by the coefficient and transmitting the multiplied value. a full-scale correction circuit having a cascade connection of the origin correction circuit and the full-scale correction circuit, a coordinate signal indicating the input coordinates to the coordinate input device is provided to the input end thereof, and a coordinate signal whose position is corrected is output from the output end thereof; It has a configuration that sends out.

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 2 is a circuit diagram showing a first embodiment of the present invention. The signal X ₁ is an analog signal of a voltage proportional to the X coordinate of the input point to the input surface 10 in FIG. The variable resistor V _R is a manual potentiometer, and the voltage between DC voltage +V and -V
It is provided to obtain an offset signal for V _C.
The adding circuit 12 is an analog adding circuit in which a resistor R is connected in series to one input terminal of the operational amplifier 13, and another resistor R is connected between the input terminal and the output terminal. That is, the adder circuit 12
A signal X ₂ which is an analog signal of the voltage obtained by subtracting the voltage of the signal X ₁ from V _C is sent to the coefficient circuit 15 . The coefficient circuit 15 is an amplifier circuit in which a resistor R is connected in series to one input terminal of the operational amplifier 14, and a manual variable resistor r is connected between the input terminal and the output terminal, and the voltage of the signal X ₂ is A signal _X3 , which is an analog signal with a voltage multiplied by -(r/R), is sent out.

The circuit of this embodiment is provided on the side of the coordinate input device 1 shown in FIG. 1, and a signal _X1 indicating the X coordinate is connected thereto. Similarly, a signal indicating the Y coordinate is also connected to a circuit having the same configuration.
If the output signals of both circuits are sent to the control device 3, there is no need for position correction in the control device 3, and the input operator can perform initial calibration at any time by adjusting variable resistors V _R and r. I can do it. At the time of initial calibration, first enter the origin Oi with pen 11,
The variable resistor V _R of both circuits is adjusted so that the cursor display C matches the origin Od, and the origin initial calibration is performed.
Next, input the full scale point Fi with the pen 11, adjust the variable resistors r of both circuits so that the cursor display C matches the full scale point Fd, and perform initial full scale point calibration. The voltage of signal X ₃ at the input is the voltage of the offset signal from the voltage of signal X ₁ .
The voltage is equal to the value obtained by subtracting V _C multiplied by (r/R). Therefore, the signal X ₃ becomes an analog signal obtained by position-correcting the signal X ₁ .

In this embodiment, the position correction is performed immediately by analog signal processing, does not require calculation processing time as in the conventional case, and a memory for storing data for position correction is provided in the control device 3. This eliminates the limit on the number of input devices that can be connected to the control device due to memory capacity constraints.

FIG. 3 is a circuit diagram showing another example of the configuration of the adder circuit 12 of this embodiment. In the circuit shown in the figure, a resistor R is connected in series to each of the two input terminals of the operational amplifier 13, another resistor R is connected between one input terminal and the output terminal, and the other input terminal is connected to the ground. This is an analog adder circuit with another resistor R connected between them. The voltage of the signal _X3 sent out by this circuit is equal to the voltage of the signal _X1 minus the voltage V _C of the offset signal.

FIG. 4 is a circuit diagram showing another example of the configuration of the coefficient circuit 15 of this embodiment. The circuit in the same figure has an amplification degree of 1
At the input end of the larger amplifier 17, a variable resistor VR
It gives a signal X ₂ divided by , and sends out a signal X ₃ with a voltage proportional to the voltage of the signal X ₂ . The polarity of this circuit may be made to match the polarity of the adder circuit 12 to which it is connected.

The first embodiment shows a case where the initial calibration is performed manually. However, if the degree of position correction between the input surface and the display surface is frequently changed during input, the initial calibration may be performed manually each time. It is troublesome to have to do this. In order to eliminate this trouble, initial calibration may be performed automatically. An embodiment in which automatic initial calibration is performed will be described below.

FIG. 5 is a block diagram showing a second embodiment, which has a configuration in which a circuit for automatically setting an offset signal at the time of initial origin calibration is added to the adding circuit 12 of the first embodiment. The switch SW is closed when the origin initial calibration mode is designated, forming a circuit loop for automatic setting of the offset signal. The signal X ₂ sent out by the adder circuit 12 is amplified through an amplifier 21 and then converted into a digital signal by an analog-digital converter (A/D) 22 and sent as a signal X ₂ to one input terminal of a comparator 23. sent to. The other input terminal of the comparator 23 receives a digital signal (for example, the first
A digital signal (digital signal) for displaying the origin Od of the display surface 20 in the figure is sent. The comparator 23 is
Both digital signals sent to both input terminals are compared and a pulse signal indicating the magnitude relationship between the two is sent out.

This pulse signal is sent to the correction data generation circuit 25 via the switch SW only during the initial calibration of the origin. The correction data generation circuit 25 includes a comparator 23
In response to the pulse signal sent from the digital to analog converter (D /A) Send to 26. The D/A 26 converts the digital signal sent from the correction data generation circuit 25 into an analog signal and sends it to the addition circuit 12 as an offset signal. As described above, when the magnitude relationship indicated by the pulse signal of the comparator 23 is reversed, the correction data generation circuit 25 stops changing the value of the digital signal, and holds and transmits the value at that time. At this time, the value of signal X ₂ substantially converges to zero, completing the origin initial calibration. In the input mode, the switch SW is opened and the circuit loop for automatic setting of the offset signal is opened, the voltage V _C of the offset signal maintains the value at the time of completion of the origin initial calibration, and the adder circuit 12 outputs the signal X ₁ Sends a signal that has undergone origin position correction, that is, a signal X ₂ with a voltage equal to the voltage of the signal X 1 minus the voltage V _C of the offset signal (or the voltage of the signal X ₁ subtracted from the voltage V _C ) _. do.

FIG. 6 is a block diagram showing an example of the configuration of the correction data generation circuit 25 of this embodiment. The pulse signal sent from the comparator 23 via the switch SW during the initial calibration of the origin is sent to the gate circuit 28 and the counter 2.
Sent to 7. The gate circuit 28 connects the pulse train of the clock signal to the counter 27 at the start of the origin initial calibration, and then interrupts the connection of the pulse example of the clock signal to the counter 27 when the magnitude relationship indicated by the pulse signal is reversed. It has a gate function to The counter 27 is an up/down counter that counts up or down the pulse example of the clock signal in the direction of reversing the magnitude relationship indicated by the pulse signal. The digital signal indicating the value of the count result of the counter 27 is a D/
Sent to A26.

FIG. 7 is a block diagram showing the third embodiment, in which the manual adjustment type coefficient circuit 1 of the first embodiment is shown.
5, a voltage or data adjustment type coefficient circuit 16 is used, and a circuit for automatically setting the voltage Vg or data Dg indicating the coefficient at the time of initial full-scale point calibration is added. The switch SW is closed during initial full-scale point calibration to form a circuit loop for automatic coefficient setting. This circuit loop operates in the same way as the circuit loop in the second embodiment at the time of full-scale point initial calibration, and automatically sets coefficients. i.e. signal X ₂
The voltage signal _X3 , which is the voltage multiplied by a factor, is A/D2
2, it is converted to a digital signal and becomes the signal X ₃ ,
The _value of this signal digital signal). After the convergence, the data Dg, which is a digital signal sent out by the correction data generation circuit 25, maintains the value at the time of convergence. In the input mode, the switch SW is open and the data Dg holds the value at the time of convergence, and the coefficient circuit 16 outputs the _signal
It sends out a signal _X3 which is the voltage multiplied by a factor. Therefore,
The signal _X3 is a signal obtained by performing full-scale point position correction on the signal _X2 .

FIGS. 8a and 8b are circuit diagrams each showing a configuration example of the coefficient circuit 16 of this embodiment. Figure a
is a voltage adjustment type circuit, and is a coefficient circuit in which the source and drain of the field effect transistor Q are connected to one input terminal and output terminal of the operational amplifier 14. In this circuit, the computer effect transistor Q
The degree of amplification is changed by applying a voltage Vg to the gate of and changing the resistance value between the source and drain depending on the value of the voltage Vg. In addition, the voltage
Vg is the voltage of the analog signal sent from the D/A 26 in FIG. FIG. 8b shows a data adjustment type circuit, which is a coefficient circuit in which both ends of a variable resistor 30 whose resistance value is varied according to data Dg are connected to one input terminal and output terminal of an operational amplifier 14. FIG. In this circuit, the sending data Dg of the correction data generation circuit 25 is given to the control end of the variable resistor 30,
The degree of amplification is changed by changing the resistance value between both ends of the variable resistor 30 depending on the value of the data Dg, and the D/A 26 shown in FIG. 7 is not required.

FIGS. 9 and 10 are block diagrams showing fourth and fifth embodiments of the present invention, respectively,
Both embodiments have a function of automatically performing full-scale point initial calibration. In the fourth embodiment shown in FIG. 9, an A/D 31 is used instead of the coefficient circuit 16 and A/D 22 in the third embodiment (see FIG. 7).
and input the signal X ₂ to the analog input terminal of A/D31.
and also a voltage at the reference voltage input terminal of A/D31.
An offset signal of Vg is applied, and a signal X ₃ obtained by digitally converting the signal X ₂ using the voltage Vg as a reference voltage is sent out and also sent to the comparator 23 . Obviously, upon completion of the full-scale point initial calibration, the signal
X ₃ value and full scale point data generation circuit 29
The value of the digital signal sent from

In the fifth embodiment shown in FIG. 10, a D/A is used instead of the coefficient circuit 16 of the third embodiment (see FIG. 7).
32, and input a signal to the reference voltage input terminal of the D/A 32.
X ₂ is applied, and data Dg is applied to the digital input terminal of the D/A 32, and a signal X ₃ obtained by converting the data Dg into an analog signal using the voltage of the signal X ₂ as a reference voltage is sent out and also sent to the A/D 22. Obviously, upon completion of the full-scale point initial calibration, the signal
X ₃ value and full scale point data generation circuit 29
is substantially equal to the value of the digital signal sent out by the .

The adder circuit 12 of the second embodiment and the circuit of any one of the third to fifth embodiments are connected to the first embodiment.
If they are connected in cascade as in the embodiment described above, a position correction means that automatically performs the initial calibration is obtained. Note that the functions of the comparator 22 and the correction data generation circuit 25 in the second to fifth embodiments, that is, the signal
The function of comparing X ₂ or X ₃ with reference point (origin or full scale point) data, and the function of generating and storing correction data according to the comparison results, are
It is clear that this can also be realized by program control using a processor built into the coordinate input device.

As is clear from the above description, the present invention can realize a position correction method for coordinate input devices that has faster processing speed than conventional methods and does not have a limit on the number of input devices that can be connected to a control device as in conventional methods. effective.

[Brief explanation of drawings]

Fig. 1 is a block diagram for explaining a correction method for a coordinate input device, Figs. 2 to 4 are circuit diagrams showing embodiments of the present invention, and Figs. 5 to 7 show embodiments of the invention. Block diagram shown in Figure 8a and b
9 is a circuit diagram showing an embodiment of the present invention, and FIGS. 9 and 10 are block diagrams showing embodiments of the present invention. 1... Coordinate input device, 10... Input surface, 11...
... pen, 2 ... image display device, 20 ... display surface,
3...Control device, 12...Addition circuit, 15, 16
... Coefficient circuit, 17, 21 ... Amplifier, 22, 3
1...Analog-digital converter (A/D),
23...Comparator, 24...Origin data generation circuit,
25... Correction data generation circuit, 26, 32... Digital-analog converter (D/A).

Claims (1)

[Claims] 1. A first variable means for varying the voltage of a first electrical signal indicating the amount of shift of the origin during origin calibration, and a first variable means for shifting the voltage of the received signal by the voltage of the first electrical signal. a second variable means for varying a coefficient indicating a magnification rate of coordinates during full scale calibration; and a coefficient circuit for multiplying the voltage of a received signal by the coefficient and transmitting the multiplied voltage of the received signal. and a full-scale correction circuit having the origin correction circuit and the full-scale correction circuit connected in cascade, a coordinate signal indicating the input coordinates to the coordinate input device is supplied to the input end of the origin correction circuit, and the position-corrected coordinate is output from the output end of the full-scale correction circuit. A position correction method for a coordinate input device, characterized in that a signal is transmitted. 2. The position correction system for a coordinate input device according to claim 1, wherein the first variable means includes a variable resistor for varying the voltage of the first electric signal. 3. The position correction system for a coordinate input device according to claim 2, wherein the variable resistor can be changed manually. 4. The position correction system for a coordinate input device according to claim 1, wherein the second variable means includes a variable resistor for varying the coefficient. 5. The position correction system for a coordinate input device according to claim 4, wherein the variable resistor can be changed manually. 6. The first variable means includes a comparison means for comparing a value of a digital signal obtained by digitally converting the transmission signal of the addition circuit with a value of predetermined origin data, and a comparison result of the comparison means during the origin calibration. In response, the voltage of the first electric signal is varied so that the value of the digital signal converges to the value of the origin data, and after the convergence, the voltage of the first electric signal at the time of convergence is maintained. 2. A position correction system for a coordinate input device according to claim 1, further comprising a control means provided with an offset signal generation means. 7. The second variable means includes a comparison means for comparing a value of a digital signal obtained by digitally converting the transmission signal of the coefficient circuit with a value of predetermined full-scale point data, and a comparison means for comparing the value of the digital signal obtained by digitally converting the transmission signal of the coefficient circuit, and a comparison means for comparing the value of the digital signal obtained by digitally converting the transmission signal of the coefficient circuit and the value of the predetermined full-scale point data at the time of the full-scale calibration. Coefficient generating means is provided for varying the coefficients so that the value of the digital signal converges to the value of the full scale point data in response to the result, and for holding the coefficients at the time of convergence after the convergence. A position correction system for a coordinate input device according to claim 1, comprising a control means.