JPS6162914A - Correction system for inclination of coordinate input device - Google Patents

Abstract

PURPOSE:To make an inclination correction which is conventionally impossible by generating the quantity of correction of the inclination of each coordinate axis from the X and Y coordinate signals of an input point, and varying, setting, and adding their coefficient during calibration. CONSTITUTION:A circuit by which a coordinate input device perform inclination correction consists of amplifiers 4X-5X and 4Y-5Y, variable resistors VRX and VRY, and adders 6X and 6Y. Coordinate signals (x) and (y) of the X and Y axes are inputted thereto from the coordinate input device and signals x0 and y0 after the coordinate axes centered on the origin of a coordinate system assumed on an input surface are rotated as specified are outputted. The origin positions of the input and output surfaces are corrected during calibration at the start of input. Then, a specific input point on the X axis (Y axis) on the input surface is inputted and said variable resistance VRX (VRY) is adjusted manually so that said point is outputted at a specific position on the output surface, thereby correcting the inclination of the X axis (Y axis). Further, size correction between an input and an output is made at a predetermined full-scale point.

Description

[Detailed description of the invention] The present invention relates to a tilt correction method for a coordinate input device.

Conventionally, when a pattern such as characters or figures input on the input surface of a coordinate input device is sent to an output device (for example, an image display device or a figure plotter) for reproduction and output, the output pattern is obtained at the desired position and size. Therefore, the electrical signal (coordinate signal) K indicating the input cover pattern is subjected to origin position correction and size correction before being sent to the output device.

However, many coordinate input devices are of the type in which a piece of paper is placed on the input surface and input is made using a marking tool on the paper surface, or of the type in which a transparent input surface is provided close to the output surface. In the former type, it is difficult to place the paper so that it is not tilted at all with respect to the assumed coordinate axis on the input surface, and in many cases, the output cut (turn is tilted with respect to the input cover turn on the paper surface) is difficult. This tilt cannot be corrected by the above-mentioned origin position correction and lens correction. Also, among the latter types, when projecting an image from the rear onto a screen that is the output surface or using an abrogator It is difficult to prevent the screen and rear projector from tilting at all when installing them, and in many cases, a difference in tilt occurs between the input cover turn and the output cover turn.This tilt is also caused by the origin position correction described above. and cannot be corrected by size correction.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tilt correction method for a coordinate input device for correcting a tilt that cannot be corrected in the past.

The method of the present invention is to receive X and yiw signals respectively indicating the X and X coordinate values of the input point to the coordinate input device, and multiply the X and X coordinate values by first and second coefficients [
Generates first and second electric signals indicating the amount of correction of the tilt of each coordinate axis, and when calibrating the tilt of each coordinate axis, the first electric signal
and first and second variable coefficient means capable of varying and setting a second coefficient;
@1 adding means for sending an X-coordinate signal whose coordinate axis inclination is corrected by adding the electric signals of the X-coordinate signal and the first electric signal; and a second addition means for sending out.

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

FIG. 1 is a block diagram showing a first embodiment of the present invention. The signals X and Y are coordinate signals sent from the coordinate input device, and are electric signals indicating the X coordinate and the X coordinate of the input location on the input surface. That is, the signals X and y are analog signals in which each voltage has a value proportional to the X coordinate and the X coordinate of the input location. Amplifier 4X and 4
Both Y are inserted and connected as buffers, and the respective signals
Signals -X and -y, which are obtained by inverting the polarities of signals X and y, are applied to the other ends of variable resistors VRX and VRY via Y. The amplifier 4X (or 4Y) is an amplification circuit with an amplification factor of 1, and for example, as shown in the figure, the voltage at the output end of the operational amplifier 14 may be directly connected as a feedback to the input leakage.

The amplifier 5X (or 5Y) is an amplifier circuit with an amplification factor of -1. For example, as shown in the figure, a resistor R is connected in series to the input beak of the operational amplifier 15, and the voltage at the output terminal is connected to another resistor R. [If you connect the feedback to the input end, it will be stormy. The variable resistor VRX (or VRY) is a voltage meter that can manually adjust the voltage division ratio, and is provided to obtain a slope correction signal of a voltage intermediate between the signals X and -X (or the signals y and -y). Variable resistor VRY (or VRX
) is sent to one input terminal of adder 6X (or 6Y). The adder 6X (or 6Y) is an analog addition circuit that adds the voltages of the above-mentioned slope correction signal and signal X (or y), and sends out a signal xo (or %) of the voltage of the addition result.

Obviously, the voltage of the signal Xo (or yo) is the linear combination of the voltages of the signals X and y. The value corresponds to the coordinate (or Yw1 mark) k. Therefore, by adding and connecting the circuit of this embodiment to a coordinate input device, it is possible to add a new tilt correction function to the conventional origin position correction and size correction functions.

In other words, when calibrating the initial input, the origin position is corrected by first inputting to the origin of the input surface and outputting to the origin of the output surface, and then correcting the origin position on the Y axis (or Y axis) of the input surface Manually adjust the variable resistor VRX (or VRY) so that it is input to a predetermined point on the output surface and output on the Y-axis (or Y-axis).
Performs tilt correction.

Further, size correction between the input and output is performed at a predetermined full scale point to complete the initial calibration.

In the input mode after completion of this initial calibration, the coordinate signal is corrected for the origin position, size, and tilt by the circuit of this embodiment, and the output cover pattern is obtained at the desired position and size, and with the tilt with respect to the input cover pattern removed. can get.

By providing a tilt correction function that was not available in the past, when placing paper on the input surface or installing an ablator, there is no need to spend a long time positioning the input surface so that it is not tilted with respect to the coordinate axes, which saves time. After positioning within the camera, tilt correction can be easily performed. In addition, if you print each point for initial calibration on the input paper in advance, such as the origin, the calibration points on each coordinate axis, or the full-scale point, you can avoid printing misalignment or tilting with respect to the coordinate axes of the input surface. Even if the output pattern is placed at a desired position and size, an initial calibration is performed before inputting, and an origin position correction, a size correction, and a tilt correction are performed to obtain an output pattern at a desired position and size and without tilt. Furthermore, initial calibration can also be performed very easily in the case where a paper with a copy of the output pattern is placed on the input surface as it is and a new pattern is inputted on top of the already output pattern.

The first embodiment shows a case in which initial calibration of tilt correction is performed manually, but an embodiment in which a means for automatically performing initial calibration is provided in order to eliminate the trouble of performing initial calibration manually is described below. explain.

FIG. 2 is a block diagram showing the second embodiment. In place of the variable resistors VRX and VRY of the first embodiment, variable resistors 7X and 7Y, and control circuits 8X and 8Y are provided to control the voltage division ratio between the two.

FIG. 3 is a block diagram showing an example of the configuration of the control circuit 8X of this embodiment. The control circuit 8X is supplied with a signal XO from the adder 6X. The signal Xo is converted into a digital signal by an analog-to-digital converter (A/D) 12 and sent to one input terminal of a comparator 13. The other input terminal of the comparator 13 is supplied with a digital signal indicating a zero value from the reference data generation circuit 18. The comparator 13 compares the values of the digital signals sent to both input ends, generates a pulse signal indicating the magnitude relationship between the two, and outputs a pulse signal to the switch SW.
send to The switch SW is a switch that is closed only during initial calibration of the Y-axis inclination.

On the other hand, the gate circuit 20 starts sending a pulse train of the clock signal to the counter 19 at the start of the initial calibration of the Y-axis inclination,
It has a gate function that stops sending out the pulse train of the clock signal to the counter 19 when the magnitude relationship of the pulse signal sent from the comparator 13 via the switch SW is reversed. The counter 19 is an up-down counter that up-counts or down-counts the pulse train of the clock signal so as to equalize the voltage division ratio of the variable resistor 7Y in the direction of reversing the magnitude relationship indicated by the pulse signal sent via the switch SW. It is Kawanta. A digital signal indicating the count result value of the counter 19 is sent to the variable resistor 7Y. When the magnitude relationship of the pulse signals sent from the comparator 13 is reversed, the gate circuit 20 stops sending out the pulse train of the clock signal.

After this time, the counter 19 continues to send out a digital signal holding the count result when the pulse train is stopped. At this time,
Signal X obtained by digitally converting signal Xo.

converges to substantially zero, completing the initial calibration of the X-axis tilt.

The control circuit 8Y also has the same configuration as the control circuit 8X, and automatically controls the voltage division ratio of the 5M variable resistor 7X so that the voltage of the signal yo substantially converges to zero during the initial calibration of the X-axis tilt. adjust.

In input mode, switch SW opens and variable resistor 7X
The partial pressure ratios of and 7Y are maintained at the values at the time of completion of the initial calibration of the inclinations of both coordinate axes, and the signals Xo and yo become signals obtained by performing inclination correction on the signals X and y.

FIG. 4 is a block diagram showing a third embodiment of the present invention. In this embodiment, the signals X and Y obtained by converting analog coordinate signals into digital signals are converted to signal
Send yo. Signal X (or Y) is sent to multiplier 17X
(or 17Y) and adder 16X (or 16
Y). Multiplier 17X (or 17Y) and adder 16X (or 16Y) are digital multipliers and adders, respectively. The multiplier 17X (or 17Y)' receives the digital signal sent from the control circuit 9Y (or 9X) and the signal X (or Y).
), the digital signal for tilt correction indicating the multiplication result with
It is sent to adder 16Y (or 16X). Adder 16Y
(or 16X) is the multiplier 17X (or 17Y)
) Signal Yo (or Xo
), and also sends this to the control circuit 9Y (or 9
Send to X).

The control circuits 9X and 9Y each have a configuration in which the A/D 12 is removed from the control circuits 8X and 8Y of the second embodiment, and the other coordinate component with respect to the coordinate axis is substantially zero at the time of initial calibration of the tilt of each coordinate axis. Multiplier i so that it converges to
Automatically adjusts the digital signal value sent to 7Y and 17X.

In this embodiment, the analog signal processing circuit of the second embodiment is entirely constructed with a digital signal processing circuit, and it can also be configured to operate under program control using a processor such as a microphone i or a combination processor. It is clear that this can be achieved.

As is clear from the above description, the present invention has the effect of realizing a tilt correction method for a coordinate input device that enables tilt correction, which was conventionally impossible to correct.

[Brief explanation of drawings]

1 to 4 are block diagrams showing embodiments of the present invention. 4X, 4Y, 5X, 5y...Amplifier, VRX
, VRY. 7X, 7Y...Variable resistance, 6X, 6Y, 16X
, 16Y... Adder, 17X, 17Y...
... Multiplier, 8X, 8Y. 9X, 9Y... Control circuit.

Claims (4)

[Claims] (1) Receiving X and Y coordinate signals indicating the X and Y coordinate values of input points to the coordinate input device, respectively, multiplying the X and Y coordinate values by the first and second coefficients to calculate the amount of correction for each coordinate axis inclination. and when calibrating the tilt of each coordinate axis, said first and second electrical signals, respectively.
first and second variable coefficient means capable of varying and setting coefficients; and a first variable coefficient means for adding the X coordinate signal and the second electric signal to send out an X coordinate signal whose coordinate axis inclination is corrected. and a second addition means for adding the Y coordinate signal and the first electric signal to send out a Y coordinate signal whose coordinate axis tilt is corrected. Correction method. (2) The first and second variable coefficient means each include:
Comparing means for comparing the values indicated by the sending signals of the first and second adding means with the values of predetermined reference data; control means for varying the first and second coefficients so that the signal value converges to the value of the reference data; and coefficient generating means for holding the coefficients at the time of convergence after the convergence. A tilt correction method for a coordinate input device according to claim (1). (3) The tilt correction method for a coordinate input device according to claim (1), wherein the first and second variable coefficient means each have a variable resistance for varying the first and second coefficients. . (4) The tilt correction method for a coordinate input device according to claim (3), wherein the variable resistor can be changed manually.