JPH0262005B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for correcting read coordinates in a digitizer that reads X and Y coordinates using a common data processing system.

Set the X, Y coordinates to one cursor (or pin), 1
An example of a digitizer read by a common data processing system consisting of two detection switches and a processing device will be explained based on FIG. Loop formed by coil x ₁
An alternating current electromotive force is induced in ~ _x4 and _y1 ~ _y5 .
Therefore, switch 2 is switched to loop x ₁ to _{x 4} and
By detecting the induced electromotive force of y ₁ to _{y 5} and reading the addresses of loops x ₁ to x ₄ and y ₁ to y ₅ where the electromotive force is maximum, the position of the excitation coil, that is, the cursor 1 (X, Y coordinates).

In such a digitizer, since the X and Y coordinates are not read simultaneously, when the cursor is moved at a certain speed, an error occurs due to the difference in reading time between the X and Y coordinates.
That is, as shown in Figure 2, the trajectory of the cursor is
Then, at time t ₁ , the X coordinate of point A ₁ on trajectory l _is
If we read the Y coordinate Y ₁ of point A ₁ ' on trajectory l at time t ₁ ', the actual measurement point is point B whose coordinates are (x ₁ , y ₁ ).
Therefore, the actual measurement point B deviates from the locus l.

The present invention was made in view of the above circumstances, and its purpose is to use a cursor (or pen) in a digitizer that reads X and Y coordinates alternately (that is, discretely) using a common data processing system. An object of the present invention is to provide a method for correcting read coordinates in a digitizer, which can reduce the amount of deviation in the trajectory of a cursor by correcting errors caused by movement of the digitizer.

Hereinafter, the present invention will be explained based on the accompanying drawings.

As shown in Figure 3, the trajectory l of the cursor is such that the X and Y coordinates are read alternately by the device shown in Figure 1, and the measurement times tn, tn ¹ (n is a positive integer) , the point on the trajectory l at tn < tn ¹ < tn + 1) is An, An ¹ , and the X coordinate is at the measurement time tn,
Read the Y coordinate at measurement time tn ¹ , and let these reading values be Xn and Yn.

Y for the X coordinate Xn read in this way
The coordinate Yn ¹ is corrected as the average value Yn- ₁ +Yn/2 of the Y coordinates Yn- ₁ and Yn read immediately before and after the X-coordinate Xn. X coordinate for Y coordinate Yn read in reverse
Xn ¹ is corrected as the average value Xn+Xn+ ₁ /2 of the X coordinates Xn and Xn+ ₁ read immediately before and after the Y coordinate Yn.

After the above correction, the measurement time interval tn
Since the amount of cursor movement at -tn-1, tn ¹ -tn-1 ¹ is very small, the amount of cursor movement at each interval can be regarded as a straight line, and
Since the reading time relative to the cursor movement speed is very small, the coordinate reading interval tn−tn ¹ −1, tn ¹
Since -tn can be considered to be equal, the corrected coordinates Xn ¹ and Yn ¹ can be considered to be on the trajectory l, and the reading error with respect to the moving speed can be ignored.

In addition, the above correction values Xn ¹ and Yn ¹ can be calculated from the required two values from the memory because the reading coordinates are temporarily stored in the memory in the digitizer shown in Fig. 1.
This can be easily determined by reading out the reading coordinates and calculating their average value using the calculation section.

As described above, the present invention allows the reading coordinates of either the X coordinate or the Y coordinate to be determined by
Since the correction is made by averaging the coordinates read immediately before and after one reading coordinate, the correction value almost matches the trajectory of the cursor (or pen), and the reading error due to the moving speed is so small that it can be ignored. Become.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a digitizer that reads X and Y coordinates using a common data processing system, FIG. 2 is a graph illustrating a conventional example, and FIG. 3 is a graph illustrating an example of the present invention. 1...Cursor, 2...Switch.

Claims (1)

[Claims] 1. In a digitizer that reads the X and Y coordinates alternately using a common data processing system, the coordinates of the other one of the X and Y coordinates are read immediately before and after the other. A method for correcting read coordinates in a digitizer, characterized in that the coordinates are averaged.