JPH10232736A - Coordinate detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coordinate detector with which detecting processing speed can be remarkably accelerated. SOLUTION: A moving distance x1 in X-axis direction between the last detected position P1 of moving coordinate indicator and a position P2 detected this time is found, a moving distance x2 equal with the moving distance x1 in X-axis direction is added to the position P2 detected this time as a moving distance in X-axis direction, and the next position P3 of coordinate indicator is inferred. The similar inference is performed concerning Y axis as well. With a detection loop coil LXn5 , in which the position P3 provided by such inference exists, as a center, detection loop coils LXn4 and LXn6 (range A30 ) on both the sides are detected and scanned and the next position of coordinate indicator is detected. Since the repetition of partial scan or the re-execution of whole scan is not performed, the detecting processing speed can be remarkably accelerated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate detecting device for detecting coordinates of a position on a tablet designated by a coordinate indicator.

[0002]

2. Description of the Related Art A coordinate detecting device is generally called a digitizer, and various types have been proposed. One of these methods is an electromagnetic induction method. This electromagnetic induction method uses the phenomenon that a coordinate indicator that generates magnetic flux is brought close to the detection loop conductor laid on the tablet and the magnetic flux crosses the detection loop conductor, thereby inducing an induced voltage in the detection loop conductor. It is a method to do. This will be described with reference to FIG.

FIG. 4 is a block diagram of a coordinate detecting device.
In this figure, reference numeral 1 denotes a coordinate indicator having an excitation circuit 1a and a coil 1b. Reference numeral 2 denotes a position detection unit (tablet) that detects a position indicated by the coordinate indicator 1, and includes a large number of detection loop coils arranged in the X-axis direction and a large number of detection loop coils arranged in the Y-axis direction. Have been. Reference numeral 3X denotes an X-axis direction selector unit, and 3Y denotes a Y-axis direction selector unit, which sequentially selects and scans each detection loop coil of a detection loop coil group in each axis direction. Reference numeral 4 denotes a signal waveform shaping unit, which amplifies a detection signal obtained by scanning the X-axis direction selector unit 3X and the Y-axis direction selector unit 3Y, adjusts the gain through a band-pass filter, and shapes a predetermined frequency signal. I do. Reference numeral 5 denotes an A / D converter for converting the signal obtained by the signal waveform shaping unit 4 into a digital value. Reference numeral 6 denotes a coordinate detection arithmetic control unit which detects the coordinates designated by the coordinate indicator 1 based on the detection signal from the A / D converter 5, and also selects an X-axis direction selector unit 3X and a Y-axis direction selector unit 3Y. Control the scanning of. The coordinate values obtained by the coordinate detection calculation control unit 6 are output to a host computer (not shown) as position information specified by the coordinate indicator 1.

FIG. 5 is a view showing detection loop coils in the X-axis direction and the Y-axis direction laid on the tablet shown in FIG. In this figure, L _X0 ,..., L _Xj,.
Xn is a detection loop coil in the X-axis direction, L _Y0 ,..., L
_Yi ,..., L _Ym represents a detection loop coil in the Y-axis direction. In the case shown, the coordinate indicator 1 exists in the detection loop coil L _Xj in the X-axis direction and exists in the detection loop coil L _Yi in the Y-axis direction.

Next, the operation of the coordinate detecting device will be described with reference to FIGS. FIG. 6 is a flowchart for explaining the operation of the coordinate detection calculation control unit 6 shown in FIG.
6 is a wiring diagram of a part of a detection loop coil group of the tablet 2. FIG. Here, since the operation of detecting the X-axis coordinate and the operation of detecting the Y-axis coordinate are the same, in the following description, only the X-axis coordinate detection will be described, and the description of the Y-axis coordinate detection will be omitted. At the time of coordinate detection, first, the coordinate detection arithmetic control unit 6
By instructing the axial selector 3X, the detection loop coil L _X0 ~
L _Xn is scanned (entire scanning) to check the induced voltage of each detection loop coil induced by the instruction of the coordinate indicator 1 (procedure S ₁ shown in FIG. 6). As a result of this scanning, if the induced voltage of one or two detection loop coils is much higher than the other induced voltages, it is determined that the coordinate indicator 1 has been detected (step S ₂ ), and the one detection loop coil or One of the two detection loop coils (the one with the larger induced voltage) is assumed to be the detection center loop coil. Incidentally, if not found entire scan detection center loop coil of the steps S _1, i.e., when the coordinate indicator 1 is not detected, and repeats the processing of steps S ₁ again.

[0006] Procedure S ₁ of the entire scan result, as described above, when the detection center loop coil is assumed, the coordinate detecting operation control unit 6 in a predetermined range before and after centering the detection center loop coil scanning the detection loop coil (Step S _3). Partial scan of the procedure S ₃ (partial scan)
Is a process for preparing for a case where the detection center loop coil changes due to movement of the coordinate indicator 1 during detection (for example, movement that occurs when operating the coordinate indicator 1 to draw a figure or the like). The range of the partial scan for this purpose is determined in consideration of the following points. That is, the moving speed of the coordinate indicator 1 is usually about several cm / sec to about 2 to 3 m / sec. It is to be noted that the moving speed may be momentarily higher than this, but the frequency is extremely small and poses no problem. In this normal movement, when the detection rate is 200 points / second, the detection interval is 0.5 to 15 mm. The effective detection width of the detection loop coil is usually several mm to several tens of mm, and is equal to or approximately twice the detection interval. The range of partial scan is
In consideration of these points, the predetermined range is set around the detection loop coil of the coordinate indicator 1 which is detected this time.

FIG. 7 shows an example of the partial scanning. When the coordinate indicator 1 by the current detection process is determined to be the point P ₁ of the detection loop coil L _Xf, the partial scan to perform the next coordinate detection of the coordinate indicator 1, the range A ₁₀ in FIG. 7 This is performed for five detection loop coils centered on the detection loop coil L _Xf as shown by. Similarly, when the coordinate indicator 1 is in the point P ₂ of the detection loop coil L _Xh, the partial scan row for five detection loop coils around the detection loop coil L _Xh represented by range A ₂₀ Will be In FIG. 7, the range A ₀₀ is a partial scanning range in the case of performing the partial scanning of the detection loop coil L _Xf against seven detection loop coil.

As a result of the partial scanning, it is determined whether or not the coordinate indicator 1 has been detected within the scanned area (step S ₄ ). If not detected, the process returns to step S ₁ , and the entire scanning is performed again. I do. As described above, the case where the coordinate indicator 1 is not detected occurs because the coordinate indicator 1 moves away from the surface of the tablet 2 or moves out of the predetermined range, and the predetermined range around the detection center loop coil is determined. This is because no voltage is induced in the detection loop coil inside. Coordinate detection operation control unit 6, when the coordinate indicator 1 in partial scan by Step S ₃ is detected, the same whether determined that detection center loop coil detection loop coil in the detection is assumed previously (steps S _5), if not the same, assuming the detection center loop coil after the change as a new detection center loop coil (Step S _6), carried out again partial scan returns the process to Step S _3. In the processing of Step S _5, if it is determined that there is no change in the detection center loop coil, the detection center loop coil identified as coordinates detectable detection center loop coil, the specified detection center loop coil the front and rear of the three detection loop coils centered detecting scanning (Step S _7).

FIG. 7 shows an example of the detection scan. When the coordinate indicator 1 is the point P ₁ of the detection loop coil L _Xf, detection scanning is performed on the three detection loop coils around the detection loop coil L _Xf represented by range A _11, the coordinate indicator when the vessel 1 is in the point P ₂ of the detection loop coil L _Xh, detection scanning is performed for the three detection loop coils around the detection loop coil L _Xh represented by range a _21. It is determined whether or not each of the induced voltages detected as a result of this detection scanning is normal (step S ₈ ). If the induced voltage is abnormal, the process returns to step S ₃ . Is calculated (step S ₉ ), and the process returns to step S ₃ .

Here, an outline of the calculation of the coordinate value by the coordinate detection calculation control section 6 will be described with reference to FIGS. FIG.
FIG. 9 is a diagram showing a selected detection loop coil, and FIG. 9 is a characteristic diagram of an induced voltage induced in each detection loop coil shown in FIG. 8, and the horizontal axis represents the center position (L _1C , L _{1 C)} of the detection loop coil.
_2C and L _3C ), and the induced voltage is plotted on the vertical axis. As shown in FIG. 8, it is assumed that the position P _L2 of the coordinate indicator 1 is located at one detection loop coil L ₂ of the detection loop coil group.
According to the example shown in FIG. 7, the detection scan in this case is performed for three detection loop coils L ₁ , L ₂ , and L ₃ . Three detection loop coils L ₁ , L ₂ , L ₃
Each induced voltage obtained, as shown in FIG. 9, the center position L _1C, L _2C, the induced voltage V _L1 on the curve C _L2 corresponding to L _3C, V _L2, V _L3 of the detection loop coil . Note that the curve C _L2 is a detection loop coil induced voltage characteristic curve that moves in parallel with the displacement of the position P _{L2 in} the X-axis direction. By calculating the solution of the approximate function of the detected induced voltages V _L1 , V _L2 , and V _L3 , the X-axis coordinate value of the position P _L2 of the coordinate indicator 1 can be obtained. For simplicity, it is also possible to calculate a coordinate value by performing a comparison operation of these induced voltages. In exactly the same way, another position P of the coordinate indicator 1 shown in FIG.
_{As for L23} , its X-axis coordinate value can be obtained based on the induced voltages V _L10 , V _L20 , and V _L30 on the curve C _L23 obtained by translating the curve C _L2 in parallel. In FIG. 8, P
_L23 is the boundary of the detection area, that is, the detection loop coil L ₂
Right and in the middle of the left detection loop coil L ₃ of.

[0011]

In [0005] the conventional coordinate detection device, calculates the coordinates (locus) By repeating the partial scan subsequent processing steps S ₃ shown in FIG. In this case, the detection processing speed is greatly affected by the response speed of the actual scanning processing. In the conventional method, when a deviation from the partial scan area occurs due to the high-speed movement of the coordinate indicator 1, the process from the whole scan must be performed again. The scanning has to be repeated, which causes a problem that the detection processing speed is greatly reduced. Further, in order to avoid the repetition of the partial scanning, it is conceivable to increase the area of the partial scanning. However, in that case, the scanning time also increases, and it is not expected to improve the detection processing speed.

An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a coordinate detection device capable of greatly improving the detection processing speed.

[0013]

In order to attain the above object, according to the present invention, there is provided a tablet in which a large number of loop-shaped conductors are arranged in a predetermined axial direction, and coordinates indicating an arbitrary position on the tablet. An indicator, selector means for sequentially scanning each loop-shaped conductor, and a coordinate value of a position designated by the coordinate indicator based on a voltage of each loop-shaped conductor obtained by predetermined scanning of the selector means. A coordinate detector comprising: a coordinate calculating means for calculating the coordinate value; a coordinate value estimating means for estimating a next coordinate value based on the current coordinate value and one or more coordinate values immediately before the coordinate detector; And a detection scanning unit for scanning the predetermined number of loop-shaped conductors centered on the loop-shaped conductor including the coordinate values estimated by the above-mentioned selector means.

According to a fourth aspect of the present invention, there is provided a tablet in which a large number of loop-shaped conductors are arranged in a predetermined axial direction, a coordinate indicator for designating an arbitrary position on the tablet, and sequentially scanning the loop-shaped conductors. A coordinate detector for calculating a coordinate value of a position designated by the coordinate indicator based on a voltage of each loop-shaped conductor obtained by predetermined scanning of the selector. At
The position displaced from the current coordinate value by the difference between the current coordinate value and the previous coordinate value in the predetermined axis direction according to the moving direction of the trajectory obtained from the current coordinate value and a plurality of coordinate values immediately before the current coordinate value is the next position in the axis direction. A coordinate value estimating means for estimating the coordinate value of the coordinate value, and a loop-shaped conductor including the coordinate value estimated by the coordinate value estimating means, a speed change obtained from the current coordinate value and a plurality of coordinate values immediately before the current value. And a detection scanning means for scanning a predetermined number of loop-shaped conductors including the loop-shaped conductor by the selector means.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments.

FIG. 1 is a diagram for explaining the principle of estimation of the coordinate value estimating means of the coordinate detecting device according to the embodiment of the present invention.
The configuration of the coordinate detection device according to the present embodiment is the same as the configuration shown in FIG. 4 except for a part of the processing of the coordinate detection calculation control unit 6 shown in FIG. In FIG. 1, P ₁ is the position of the previously detected coordinate indicator 1, L _Xn1 is the detection loop coil at the position P ₁ , P ₂ is the position of the coordinate indicator 1 detected this time, L
_Xn3 the detection loop coil of the position P _2, the position P ₃ is estimated that it would become the position of the next coordinate indicator 1 in the coordinate value estimating means, L _Xn5 shows a detection loop coil position P _3. Further, x ₁ is the distance in the X-axis direction between the position P ₁ and the position P _2, x ₂ is the distance between the position P ₂ to the position P _3. In the following description as well, only the X axis will be described, and the description of the Y axis will be omitted.

Next, the operation of this embodiment will be described with reference to the explanatory diagram of FIG. 1 and the flowchart shown in FIG. In the flowchart shown in FIG. 2, the processing of steps S ₁ ~ Step S ₉ is the same as the conventional processing shown in FIG. In this embodiment, the coordinate in the processing of steps S ₉ is detected, it is determined whether the detection is 3 and subsequent detection (Step S ₁₀ shown in FIG. 2), first or second if detecting performs processing of partial scan procedure S _3. Then, from the detection of the third subsequent performs estimation of position (Step S _11), on the basis of this assumption, it performed immediately detected scan without performing partial scan.

The presumed position in steps S ₁₁ is performed as follows. That is, the coordinate detecting operation control unit, the distance in the X-axis direction between the position P ₁ position P ₂ and the previous detection of the detection time x
₁ look, the movement of the next coordinate indicator 1 is assumed to be the movement of the current moving distance x ₁ and equidistant x _2, the next time by adding the distance x ₁ (= x ₂₎ to the position P ₂ guessing the position P ₃ of the coordinate indicator 1. The detection loop coils of the position P ₃ (the case shown in FIG. 1, L _Xn5) searching, which was identified as the detection center loop coils and detects the scanning steps S _{7. Assuming} that the detection scan is scanning of three detection loop coils, the detection scan in the case shown in FIG. 1 is performed by the detection loop coils L _Xn4 , L _Xn5 , and L _Xn6 (scanning range A ₃₀ shown in FIG. 1).
Made against.

As described above, in the present embodiment, the next movement distance of the coordinate indicator in the X-axis direction and the Y-axis direction is assumed to be equal to the movement distance in each axis direction from the previous time to the current time. Since the coordinates are estimated and the detection scanning is performed with the detection loop coil at the coordinates as the center, the scanning process of the partial scanning can be omitted in the third and subsequent detections, whereby the partial scanning is repeated or repeated. Can be avoided, and the detection processing speed can be greatly improved.

FIG. 3 is a diagram for explaining another principle of estimating the coordinate value estimating means. In this Figure, P ₁₁ is the position of the coordinate indicator 1 before the previous detection, L _Xn11 the detection loop coils of the position P _11, P ₁₂ is the position of the coordinate indicator 1 of the previous detection, L _Xn13 is the position P ₁₂ detection loop coil, P ₁₃ is the position of the coordinate indicator 1 detected this time, L _Xn14 the detection loop coils of the position P _13, P ₁₄ and would be the position of the next coordinate indicator 1 in the coordinate value estimating means suspected positions, L _Xn15 shows a detection loop coil of the position P _14. Further, x ₁₁ is the distance in the X-axis direction between the position P ₁₂ to the position P _11, x ₁₂ is the position P ₁₂ to the position P
X-axis direction of the distance between _13, x ₁₃ represents the distance in the X-axis direction between the position P ₁₃ to the position P _14.

The coordinate detection arithmetic control unit calculates the distance x ₁₁ and the distance x
Judge the size relationship with ₁₂ . In the case shown, since x ₁₁ > x ₁₂ , it can be seen that the moving speed of the coordinate indicator 1 in the X-axis direction has decreased. Therefore, I guess based on the next location P ₁₄ of the coordinate indicator 1 to the following equation. _{x 13 = 2 x 12 -x 11} = x 12 - since (x ₁₁ -x ₁₂₎ ............ (1) above (1) in parentheses are the current deceleration amount, the next movement distance, assuming that the deceleration is equal to infer a deceleration component resulting current from the current travel distance (x ₁₂₎ to (x ₁₁ -x ₁₂₎ is a distance obtained by subtracting. As a result, the next coordinate indicator 1
_Is presumed to be the detection loop coil L _Xn15, and the detection scan of the three detection loop coils (the scanning range A ₄₀ shown in FIG. 3) centering on this is performed. When x ₁₁ <x ₁₂ , all the subtractions in the expression (1) are additions. In addition, for the change in the moving speed, an average value of the change in the moving speed may be obtained from more detection positions, and the next moving distance may be estimated based on the average value. As described above, by considering the change in the moving speed of the coordinate indicator, the same effect as that of the estimation processing shown in FIG. 1 can be obtained, and the estimation can be performed with higher accuracy.

Further, an estimation processing method other than the above two estimation processing will be described with reference to an example shown in FIG. In the above estimation process shown in FIG. 3, the following movement distance in the X-axis direction was estimated using Expression (1). However, in this estimation method, FIG.
As in the estimation processing method shown in (1), the next movement distance is estimated to be the same movement distance (x ₁₃ = x ₁₂ ) as this time. Then, the magnitude relationship between the distance x ₁₁ and the distance x ₁₂ is determined, and in the case shown in the figure, x ₁₁
> Because it is x _12, the detection loop coil for detecting the scanned object, one added in the negative direction end portion of the X-axis (detection loop coil L
Added _Xn13), the detection scanning range A ₅₀ and four detection loop coils. That is, in order to correct that the estimation of the moving distance (x ₁₃ = x ₁₂ ) is too large in the deceleration state, the detection scan is applied to only one detection loop coil in the negative direction to cope with this. When x ₁₁ <x ₁₂ , one detection loop coil in the forward direction is added to the detection scan.

By the way, when the estimated position of the next point is close to or near the boundary of the detection area, for example, in the case of P _L23 in FIG. 8, the detection loop coils L ₁ , L ₂ , and L _{3 use} the coordinate indicator 1.
Detection loop coils L ₂ , L ₃ , L
_It may be necessary to detect the position at ₄ . Therefore, when the distance from the estimated position to the boundary of the detection area is shorter than the predetermined distance α, four detection loop coils including the detection loop coils on both sides of the two detection loop coils including the estimated position are detected and scanned. To do it. That is, in the case of P _L23 in FIG. 8, the detection scanning is performed on the four detection loop coils L _{1 to} L ₄ . In this way, the reliability of the estimation process can be further ensured.

[0024]

As described above, according to the present invention, the next detection position is estimated based on the current detection position, and a predetermined number of loop conductors including the loop conductor at the estimated detection position are detected. Since the scanning is performed, the processing of the partial scanning can be omitted, whereby the repetition of the partial scanning and the execution of the whole scanning again can be avoided, and the detection processing speed can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a principle of estimation of a coordinate value estimating unit of a coordinate detection device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a detection operation of the coordinate detection device according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating another principle of estimation of coordinate value estimation means.

FIG. 4 is a block diagram of a coordinate detection device.

FIG. 5 is a diagram showing detection loop coils in the X-axis direction and the Y-axis direction wired on the tablet shown in FIG. 4;

FIG. 6 is a flowchart illustrating an operation of a coordinate detection calculation control unit illustrated in FIG. 4;

FIG. 7 is a wiring diagram of a part of a detection loop coil group of the tablet.

FIG. 8 is a diagram showing a selected detection loop coil.

9 is a characteristic diagram of an induced voltage induced in each detection loop coil shown in FIG.

[Explanation of symbols]

P ₁ to P ₃ detecting position L _Xn1 ~L _Xn6 detection loop coil A ₃₀ detects the scanning range

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[Procedure amendment]

[Submission date] March 28, 1997

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

Claims (4)

[Claims] 1. A tablet in which a large number of loop-shaped conductors are arranged in a predetermined axial direction, a coordinate indicator for designating an arbitrary position on the tablet, selector means for sequentially scanning each of the loop-shaped conductors, and the selector A coordinate calculating means for calculating a coordinate value of a position designated by the coordinate pointing device based on a voltage of each loop-shaped conductor obtained by a predetermined scanning of the means. Coordinate value estimating means for estimating the next coordinate value based on one or more coordinate values immediately before that, and a predetermined number of loops centered on a loop-shaped conductor including the coordinate values estimated by the coordinate value estimating means A coordinate scanning device provided with a detection scanning means for scanning the conductive wire by the selector means. 2. The method according to claim 1, wherein the coordinate value estimating means is configured to determine the current coordinate value by a difference in a predetermined axis direction between each coordinate value based on vector information obtained from the current coordinate value and the previous coordinate value. A coordinate detection device for estimating that the position displaced from the next coordinate value is the next coordinate value in the axial direction. 3. The coordinate value estimating means according to claim 1, wherein said coordinate value estimating means calculates a current coordinate value in a predetermined axis direction in accordance with a change in a moving direction and a speed of a trajectory obtained from the current coordinate value and a plurality of coordinate values immediately before said coordinate value. And that the position displaced by the value obtained by adding or subtracting the difference between the previous two coordinate values and the previous coordinate value with respect to the difference between the previous coordinate value is assumed to be the next coordinate value in the axis direction. Coordinate detection device. 4. A tablet on which a large number of loop-shaped conductors are arranged in a predetermined axial direction, a coordinate indicator for designating an arbitrary position on the tablet, selector means for sequentially scanning each of the loop-shaped conductors, and this selector A coordinate calculating means for calculating a coordinate value of a position designated by the coordinate pointing device based on a voltage of each loop-shaped conductor obtained by a predetermined scan of the means. The position displaced from the current coordinate value by the difference between the current coordinate value and the previous coordinate value in the predetermined axis direction according to the moving direction of the trajectory obtained from the plurality of immediately preceding coordinate values is the next coordinate value in the axis direction. Coordinate value estimating means, and a loop-shaped conductor including the coordinate values estimated by the coordinate value estimating means, according to the change in speed obtained from the current coordinate value and a plurality of coordinate values immediately before the current value. A coordinate detecting apparatus comprising: a loop-shaped conducting wire deviated from the center; and a detection scanning means for scanning a predetermined number of loop-shaped conducting wires including the loop-shaped conducting wire by the selector means.