JP2831715B2 - Position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention relates to a position detection device using an online handwritten character recognition technology.

(Conventional technology) In recent years, CAD (Computer Aided Design) and handwritten character recognition devices using online handwritten character recognition technology,
A position detecting device generally called a tablet is widely used. This tablet has X and Y orthogonal to each other
It is a flat plate composed of a plurality of electrodes in different directions, and by performing a writing operation on this with an input pen, the coordinates of the input position are detected.

In this tablet, when coordinates are detected in response to handwriting input, an error may occur in the detected coordinates due to external noise such as static electricity. As a method for removing this kind of error in the detected coordinates, conventionally, when an input is made from coordinates that are at least a certain distance away from the previously detected coordinates,
A method of removing this as erroneous coordinate detection has been adopted. In other words, the upper limit of the speed when drawing with the input pen is obtained, and when coordinates in a range exceeding this speed are detected,
The coordinate detection is regarded as being erroneous and is removed.

FIG. 4 shows such a conventional coordinate detection method. In the figure, P _n-1 and P _n indicate coordinate positions detected at sampling timings t _n-1 and t _n , respectively. The sampling timing follows a sampling clock for detecting the coordinates of the tablet, and the interval is constant. Further, r _n and r _{n + 1} are the radii of the circles indicating the allowable input ranges at the sampling timings t _n and t _{n + 1} , respectively. The allowable input range is always constant and this radius r _n , r
The value of _{n + 1} is also equal.

In the figure, with respect to P _n-1 which is detected by the sampling timing t _n-1, because the P _n detected at the next sampling timing t _n that are within the allowable input range of the radius r _n, normal input And the coordinate data is sent to the information processing apparatus as valid data. However, since P _{n + 1} detected at the next sampling timing t _{n + 1} is out of the allowable range of the radius r _{n + 1} , it is regarded as erroneous detection due to noise or the like, and its coordinate value is ignored or removed. You.

(Problems to be Solved by the Invention) However, in the conventional method in which a coordinate is detected in a coordinate range outside a certain range, it is regarded as an erroneous detection. Can not follow. Further, if the allowable input range is unnecessarily widened in order to improve the input followability, erroneous detection due to noise or the like is likely to occur.

The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a position detecting device capable of reliably removing erroneous detection due to external noise such as static electricity while enabling high-speed input.

[Structure of the Invention] (Means and Actions for Solving the Problems) The present invention is directed to a case in which an input frame is set for each entry, and the pen tip of an input pen is set. The position coordinates and the moving speed are detected, the allowable input speed limit is determined from the detected position coordinates, and the validity / invalidity of the next detected coordinates is determined based on the allowable input speed limit and the pen moving speed. When writing large characters and figures in a large input box, the maximum input speed is large.When writing small characters and figures in a small input box, the maximum input speed is Since it becomes smaller, it is possible to set an appropriate allowable input speed corresponding to the expected maximum input speed according to the size of the input frame.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the circuit configuration, wherein 1 is a tablet plate, which is constituted by arranging a plurality of X electrodes 2 and Y electrodes 3 in a matrix. A voltage is applied to each electrode of the X electrode 2 by the X electrode drive circuit 4 and a voltage of the Y electrode 3 to the Y electrode 3 by the Y electrode drive circuit 5, respectively. The X electrode drive circuit 4 and the Y electrode drive circuit 5 are both driven and controlled by the tablet controller 6. The tablet controller 6 also drives and controls the input pen 7. The input pen 7 has an electrode inside. By performing a writing operation with the input pen 7 on the tablet board 1 and instructing the coordinate operation, the voltage applied to the X electrode 2 and the Y electrode 3 is applied to the internal electrodes of the input pen 7 by electrostatic induction. It is captured as a voltage signal, and the voltage signal is sent to the tablet controller 6. And the tablet controller 6
Converts the voltage signal into coordinate data of the X coordinate and the Y coordinate of the designated coordinates on the tablet 1. The tablet controller 6 executes the above control in accordance with the control command sent from the information processing device 9 via the host interface 8, and sends out the obtained coordinate data to the information processing device 9 via the host interface 8. . The information processing device 9 includes, for example, a CAD system or a personal computer, and performs processing using coordinate data transmitted from the tablet controller 6 via the host interface 8.

The operation for detecting the position in the above configuration will be described with reference to FIG.

First, at the beginning of the operation, the system is started in step S1 to display an initial input screen as shown in FIG. In step S2, area information (input frame information) is set in the information processing apparatus 9 for the initial screen data.

The following operation is executed by the tablet controller 6, and in order to start the operation, it is determined whether or not the switch of the input pen 7 is turned on as shown in step S3 by sampling a voltage signal. The input pen 7
When it is turned on, the coordinate data is converted in step S4, and coordinate data composed of X coordinate data and Y coordinate data on the tablet board 1 is detected. The detected coordinate data is sent to the information processing device 9, and in steps S5 to S7, which of the area information A, B, and C is determined in order. If the region information is, for example, A, the process proceeds from step S5 to step S8, and the input frame size (the length of the X direction frame × the length of the X direction frame) is obtained from the input frame coordinate data in the region information stored in the information processing device 9 in step S2. (The length of the Y-direction frame). The information processing apparatus 9 is comprised of allowable input movement restriction rate V _n corresponding to the input frame size data is given. Allowable input travel V
_n is given in the form of input frame size A ≦ V _n ≦ input frame size B.

As described above, the allowable input movement limit amount _VA is obtained from the input frame size. The movement limit amount V _A obtained as V _MAX, followed after it is determined whether or not the first point in step S9, the movement amount D _n of the mobile coordinates of the point P _n-1, P _n in step S10 Is within the allowable input movement limit amount _VMAX . That is, D _n = P _n
It is determined whether or not “D _n > V _MAX ” holds as −P _n−1 / T (where P _n −P _n−1 : moving distance, T: sample time). If the condition holds, the coordinate point is removed, and the process returns to step S3. If _VMAX is not exceeded, the process proceeds to step S11, where the coordinate data is set to the sample time T.
Are displayed in dots corresponding to.

If it is determined in step S6 that the area information is B, the process proceeds from step S6 to step S12,
Find the allowable input movement limit amount V _B in the same manner as 8 sets the allowable input movement limit amount V _B as V _MAX, leading to step S9.

Further, if the area information in step S7 is determined to be is C, the process proceeds from step S7 to step S13, obtains the allowable input movement restriction rate V _C in the same manner as in step S8, the allowable input movement limit amount V set _C as V _MAX, also leads to step S9.

By performing the input speed limitation by the input frame size according to the moving amount (writing speed) of the input pen 7 for a certain period of time by the above method, erroneous detection due to noise is prevented,
Further, it is possible to improve the followability of the writing speed.

[Effects of the Invention] As described above in detail, according to the present invention, the position coordinates of the pen tip of the input pen and the moving speed are determined for a case where an input frame is set for each entry. Since the allowable input speed limit is determined from the detected position coordinates and the pen speed is determined based on the allowable input speed limit and the pen moving speed, the validity / invalidity of the next detected coordinate is determined. When entering large characters and figures in a box, the maximum input speed increases, and when entering small characters and figures in a small box, the maximum input speed decreases. It is possible to set an appropriate allowable input speed corresponding to the expected maximum input speed according to the size of the input speed. In addition, it is possible to provide a position detection device capable of improving the effect of removing erroneous measurement due to noise by strictly limiting the speed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention, FIG. 2 is a flowchart showing processing contents, FIG. 3 is a diagram illustrating an input area by an input pen, and FIG. It is a figure showing the method of. 1 ... tablet plate, 2 ... X electrode, 3 ... Y electrode, 4
... X electrode drive circuit, 5... Y electrode drive circuit, 6... Tablet controller, 7... Input pen, 8... Host interface, 9.

Continuation of front page (56) References JP-A-64-14629 (JP, A) JP-A-60-114924 (JP, A) JP-A-60-97429 (JP, A) (58) Fields studied (Int .Cl. ⁶ , DB name) G06F 3/03 G06F 3/033

Claims (1)

(57) [Claims] An input pen, coordinate detecting means for detecting a position coordinate of a pen tip of the input pen, speed detecting means for detecting a moving speed of the pen tip of the input pen, and the coordinate detecting means Determining means for determining an allowable input limit speed from the detected position coordinates of the pen tip; and a pen moving speed determined by the speed detecting means and an allowable input speed limit determined by the determining means. And a determination means for determining whether the detected coordinates are valid or invalid.