JPS62126428A - Character graphic input processing system - Google Patents

Abstract

PURPOSE:To correct display due to the delay of detection and to display correctly an inputted character graphic by providing an interpolation processing part for interpolating a locus found out by a position detecting part to a control part. CONSTITUTION:A transparent tablet 2 is set up on a display part 1 so that the display contents on the display part 1 can be observed through the tablet 2, a character graphic is inputted with an input pen 3 and the position of the input pen 3 is detected by the position detecting part 5. When the locus of the input pen 3 is found out from a point of time that the input pen 3 is brought into contact with the tablet 2 by the position detecting part 5, i.e. when a pen- down point is detected, the interpolation processing part 6 interpolates the locus so as to extend it by a prescribed distance. The distance to be extended can be selected in accordance with a drawing speed. Thereby, a shift from a real pen-down point due to the delay of position detection in the position detecting part 5 can be corrected and the corrected value can be displayed on the display part 1.

Description

[Detailed Description of the Invention] [Summary] When characters and figures are input on a tablet with an input pen, the difference between the position where the input pen actually contacts the tablet and the position obtained by position detection processing is detected using the input pen. Interpolation processing is performed on the basis of the locus of the input character and figure, so that the character figure is displayed from the position where it was actually input, thereby making it possible to accurately display the input character figure.

[Industrial application field]

The present invention relates to a text/figure input processing method in which a transparent tablet is placed on a display section, text/figures are input onto the tablet using an input pen, and the text/figures are displayed on the display section.

Cathode ray tube (CRT) display device, flat panel electroluminescent (EL)
) A transparent tablet is placed on the display unit of a display device, a liquid crystal display device, etc., characters and figures are inputted on the tablet with an input pen, and displayed on the display unit by detecting the position of the input pen, Systems that perform handwritten input are known.
There is a demand for characters and graphics that are the same as characters and graphics input by handwriting to be displayed on the display unit.

[Conventional technology]

For example, as shown in FIG. 5, the character/graphic input device includes a transparent tablet 22 placed aX on a flat electroluminescent (EL) display section 21, and an input bezel 2 placed on the tablet 22.
3 is used to input characters and figures, and shows the case of a capacitive coupling type. The tablet 22 is configured by laminating, for example, an acrylic resin plate 22a, a transparent resistance plate 22b, a transparent shield slope 22C, and an acrylic resin plate 22d, and the display contents of the display section 21 can be seen from above. . Incidentally, an electromagnetic coupling type tablet is also known.

Oscillators 27a and 27b are connected to the resistance plate 22b of the tablet 22.
An oscillation output signal is applied from the input pen 22 through the switches 26a and 26b so that the phase of the composite electric field corresponds to the position on the tablet 22, and the phase of the signal detected by the capacitive coupling with the input pen 23 is adjusted. A phase detecting section 24 detects a phase difference from a reference phase, and a converting section 25 including a read-only memory converts the phase information into position information and transfers the position information to a processor (not shown).

The output signals of the aforementioned oscillators 27a and 27b are respectively A.
s1n ωt , As1n(ωt-π/2), and X
.

Switches 26a and 26 for switching position detection in the Y direction
oscillator 27a, oscillator 27a,
27b is applied, and the distance between the electrodes is L, the potential e on the resistance plate 22b at position (1)
However, “O=J X L + 1
-X L 2 A yells.

This signal e is electrostatically detected by the input pen 23, and the position X of the input pen 23 can be determined from the phase θ as follows. Therefore, switch 26a
, 26b, the positions in the X and Y directions can be determined respectively. Also, since the distance is predetermined,
Once the phase θ is obtained, it can be converted into position information in the conversion unit 25 from the relationship of equation (2).

FIG. 6 is an explanatory diagram of the input pen and input section. The input pen 23 includes an insulating tip 23a at the tip, a detection electrode 23b, a switch 23c made of pressure-sensitive rubber, etc., and a shield electrode 23d.
, an insulating case 23e, a cable 23f, etc., and when the human power probe 23 is brought into contact with the tablet 22, the detection electrode 23b presses the switch 23c made of pressure-sensitive rubber or the like, thereby making the switch 23c conductive. A signal induced by the coupling between the electric field on the tablet 22 and the tip of the detection electrode 23b is input to the amplifier 31 via the switch 23c and the cable 23f.

The output of the three amplifiers is input to a comparator 34 via a low pass filter 32 and a bypass filter 33. A band pass filter is configured by the low pass filter 32 and the bypass filter 33, and the detection electrode 23 of the input pen 23
The fundamental frequency component of the signal induced in b is extracted. For example, if the frequency of the signals applied to the tablet 22 from the oscillators 27a and 27b is 4.8 KHz, the fundamental frequency of the signal induced in the detection electrode 23b of the input pen 23 is 4.8 KHz, so the cut Off frequency 5.5
A fundamental frequency signal is extracted through a KHz low-pass filter 32 and a 3.8 KHz bypass filter 33, compared with a predetermined level by a comparator 34, and a rectangular wave detection signal Vp is output from an output terminal 35. Output.

FIG. 7 is a block diagram of the position detection section, in which the oscillator 411
Frequency divider 42. The multiplexer 43 constitutes a drive signal generation section 50, and the oscillator 41 has a 19.66M
A Hz signal is outputted and added as a count clock to a counter 45, and the frequency is divided by a frequency divider 42. The frequency is divided by this frequency divider 42 to, for example, 1/4096, and 4.
Signal φ weights with 90 degree difference in phase at 8 KHz,
Outputs φ2. This signal φ0. φ2 is (signal As1n ωt shown in equation 11, As1n (ωt-π/
2), and serves as a drive signal for the tablet 22.

Also, exclusive OR circuit 44. Counter 45. Register 47.
48 constitutes a phase difference measuring section 51. The mode selection unit 46 selects between a calibration mode and a measurement mode.The measurement mode consists of an X measurement mode and a Y measurement mode, and a flag indicating each mode is output. Also, each mode is set to one of the drive signals (4,8 KHz rectangular wave), for example.
It consists of 2 periods, and the 1st to 8th periods are the settling time of the filters 32, 33, etc. of the input section due to mode switching,
The 9th to 12th periods are the actual phase difference measurement time.

In the calibration mode, by controlling the multiplexer 43 to set the drive signal φi=φ1=A sin ωt, that is, by driving the tablet 22 with the drive signal φ1 having the same phase, the phase difference depending on the position on the tablet 22 is eliminated. Also, the counter 45 is cleared, and the detection signal V of the input pen 23
The output signal of the exclusive OR circuit 44 becomes "1" for a time corresponding to the phase difference between p and the signal ψ1, that is, the phase shift of the input section.
”, and the counter 45 counts down the output signal of the oscillator 41.The count contents of the counter 45 are set in the register 48 as a calibration value.Please note that the phase shift due to temperature changes or changes over time in the input section may occur. If it is 0, the phase difference between the detection signal Vp and the signal φ1 is O, and the count content of the counter 45 is 0. Also, this calibration mode is activated when the input pen 23 is brought into contact with the tablet 22, that is, every time the pen is down. This is done once every 24 hours, and after that it is in measurement mode.

In the measurement mode, the multiplexer 43 is controlled to set the drive signal φ, = φz = Asin (ω = 1/2), and the counter 45 is set to the register 48 determined in the previous calibration mode.
After loading the contents of the 1st to 8th cycles, the 9th to 12th cycles
In each period, a time period corresponding to the phase difference between the signal φ and the detection signal Vp is counted up. When the count ends, the count contents are set in the register 47.

Therefore, the content of the register 47 is the calibration value obtained in the calibration mode, and the phase difference obtained in the measurement mode is calibrated.

The contents of this register 47 are phase information, and this phase information is used as an address in the read-only memory (ROM) 49 to read position information.If the phase information has a phase difference of 0, the position of x=O Information will be read out.

As described above, the tablet 22 by the input pen 23
Since the upper position can be detected, the information will be displayed on the display section 21 based on the detected position information.

[Problem that the invention seeks to solve]

As described above, the position detection of the input pen 23 is performed by the phase difference measurement unit 51 at regular intervals, and the detection corresponding to the measurement cycle starts from the time when the input pen 23 is actually brought into contact with the tablet 22. There will be a delay. Due to this time delay, a position shifted from the actual contact position of the input pen 23 is detected as a pen-down point. Since the speed of handwritten input is 200 to 600 mm/s, if the detection of hendown is delayed by several tens of meters, a line with a length of 2 to 10 mm will not be displayed.

Figure 8 is a handwriting characteristic measurement diagram, which shows the measured maximum drawing speed (mm/S) and bandwidth (Hz) in handwriting input, where the ・ mark indicates alphabetic character input, the O mark indicates kanji input, The X mark indicates the case of graph input.

The band on the vertical axis is the drawing point sequence x (t), y (t)
The maximum frequency obtained by Fourier transform is shown, and the sampling frequency for position detection is selected with this band in consideration. As can be seen from this measurement diagram, the speed of handwritten input is 200 to 609 mm/S.

FIG. 9 is an explanatory diagram of the position detection operation of the human pen, and when the input pen 23 is brought into contact with the tablet 22 and moved,
The position of the pen down point is Xo.

If ``Yo'' is selected, the switch 23C operates as shown as the switch detection point at a point where the input pen 23 has moved slightly. And a delay time t for preventing chattering etc.
After d, calibration mode R is entered, the calibration value is measured, and then Y
Y depending on the measurement mode.

Detection is performed, and then X, detection is performed by the X measurement mode. Similarly, the trajectory of the input pen 23 is changed to Y2.
X2. It is determined by the detection of... The detected pen-down point of the input pen 23 in the position detection section is x,...
y, so the position of the input pen 23 after td+3 is detected from the switch detection point, and the coordinate (X
o, Yo) to the coordinates (X+, Y+) are not displayed on the display unit 21.

For example, regarding “a” and rPJ shown in FIG.
Due to the delay in the position detection process mentioned above, the part indicated by the dotted line from the actual pen-down point to the point where the position detection was performed was not displayed, resulting in the input character shape being displayed with unnatural content. .

The present invention corrects the display due to the detection delay in this way,
The purpose of this is to enable input characters and figures to be displayed correctly.

[Means for solving problems]

The character/figure input processing method of the present invention corrects the deviation between the actual position of the input pen and the detected position by interpolating the trajectory of the input pen, and will be explained with reference to FIG. A transparent tablet 2 is placed on the display section 1 so that the display contents of the display section 1 can be seen through the tablet 2. Characters and figures are input using the human pen 3, and the position of the input pen 3 is controlled by the control section 4. The interpolation processing unit 6 performs interpolation processing based on the trajectory of the input pen 3 determined by the position detection unit 5, and a character/figure is input from a position close to the actual pen-down position. This is displayed on the display unit 1 as follows.

[Effect]

When the trajectory of the input pen 3 is determined from the point at which the input pen 3 contacts the tablet 2 by the position detection section 5, that is, the pen-down point is detected, the interpolation processing section 6 extends the trajectory by a predetermined distance. Interpolate as follows. This extended distance can be selected depending on the drawing speed.

Therefore, the deviation from the actual pen-down point due to the position detection delay in the position detection section 5 can be corrected and displayed on the display section 1.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a block diagram of an embodiment of the present invention, in which 11 is a processor (CPU), 12 is a main memory, 13 is a display control device, 14 is a display memory having a display capacity for at least one screen, and 15 is an electric field. 16 is a tablet control device, 17 is a transparent tablet, 18 is an input pen, and 19 is a data bus. A transparent tablet 17 is placed on the display section 15, and is configured so that the display contents of the display section 15 can be seen through the tablet 1-17.

The tablet 17 is, for example, a capacitive coupling type shown in FIG. 5, and the input pen 18 has a configuration shown in FIG. 6, for example, corresponding to the tablet 17.

Further, the tablet control device 16 has, for example, the configuration shown in FIG.
8 trajectories are required. Then, the trajectory of the input pen 18 is stored in the main memory 12, and interpolation processing is performed by the arithmetic function of the processor 11. The contents of the main memory 12 are then transferred to the display control device 13, and display information for one screen is stored in the display memory 14 and displayed on the display section 15.

In this embodiment, the position detection section 5 in FIG. 1 is realized by the tablet control section N16, and the interpolation processing section 6
This figure shows a case where the calculation function of the processor 11 is used to realize the calculation function of the processor 11.

Figure 3 is an explanatory diagram of the interpolation process, where the points to be found as actual pen-down points are (Xo, Yo), the first point detected is (X+, Y+), and the second point is (Xz, y2). ,
Let td be the delay time to prevent chattering, and t be the measurement time in each mode, and ignore the switch operation delay time due to the stroke of the manual pen 18 because it is minute.

It is assumed that the input pen 18 has a velocity of 0 at the point (Xo, Yo) and is moving at a constant acceleration until (X+, Y+) and (Xz, Yz) are measured. The velocity components Vx and Vy in the X and Y directions are Xo=X, -2AX (t
d+3 ・t)” −・(71Yo ”Y+ −−A
y (td+2 ・t)” ・−・(81 Therefore, Xo=X, +λx(XI Xz) −(91Y
, = Y, +λ'i (Y + Y 2 ) −
...The actual pen-down point (Xo, Yo) can be determined by aOl. Note that first find the X coordinate, then
This applies to the case where the coordinates are determined, but on the other hand, when the X coordinate is determined first, formula 00 and (2) 2 are opposite. Furthermore, although the case where interpolation processing is performed using two points (X+, Y+) and (Xz, Yz) is shown, it is also possible to perform interpolation processing using more points. Further, although the above-described interpolation process is linear interpolation, it is also possible to perform curve interpolation based on the trajectory of the input pen consisting of at least three points to determine the actual pen-down point.

FIG. 4 is a processing flowchart of an embodiment of the present invention,
The pen flag is set to 0 by the start (PENFG←0
)■. When there is an input such as pen-down or pen-off of the input pen, an interrupt is processed, and if it is determined that the pen is off by this interrupt information analysis, a determination is made as to whether or not the pen flag is 1. . If the pen flag is 1 (
PENFG=1), draw a point (XD, YD) and set the pen flag to 0 (PENFG-0). In this case, since the pen is turned off after pen down, the display coordinates (XD, YD) corresponding to the pen down position
A point will be displayed on the .

Also, when the pen flag is not 1 (PENFG≠1), the pen flag is set to 0 by pen off.

Furthermore, if it is determined by the interrupt information analysis (■) that the interrupt is for obtaining tablet coordinates (measurement mode), it is determined whether the pen flag is 0, 1, or 2 (■). If the pen flag is 0, it means that the input pen has just come down after touching the tablet, so convert the tablet coordinates (X, Y) to display coordinates (XD, YD), and convert these tablet coordinates (X, Y) into display coordinates (XD, YD). This is the first detection position after pen-down (IX-X, IY←Y) ([1). Then, the pen flag is set to 1, and PENFG-1)@ waits for input.

Tablet coordinates are converted to display coordinates using the input pen position (X, X coordinates) determined by the measurement mode.
This is to form display information that is converted into display coordinates corresponding to the configuration of the display section.

Also, if the pen flag is 1, this means that the second tablet coordinates have been obtained after the pen is down, so the first detected position and the second tablet coordinates (X
, Y), IX+λX(IX-X), IY+λy
(IY-Y), λX, λy are 0υ, refer to αδ formula), display coordinates (I XD, I YD
) Convert to ■. And this time, the tablet coordinates (X,
Convert Y) to display coordinates (XD, YD) 0° Then display coordinates (XD, YD), (IXD,
IYD) by linear interpolation■. That is, based on the first and second position detections described above, a position approximate to the actual pen-down position is determined by linear interpolation processing.

Then, set the pen flag to 2 (PENFG←2)■,
Waiting for input.

If the pen flag is 2, it indicates the third or later position detection, and the previous display coordinates XD and YD are saved (IXD 4-XD, IYD-YD),
In step 0, the current tablet coordinates (X, Y) are converted to display coordinates (XD, YJ). Thereafter, the process goes through steps ① and ② and waits for input.

In this embodiment, the number of position detections from pen down detection is displayed using the pen flag PENFG, and linear interpolation is performed based on the display coordinates of the first and second times, but up to the third position detection number. You can also display curves and perform curve interpolation. Furthermore, it can be applied not only to electrostatic tablets but also to electromagnetic tablets.

〔Effect of the invention〕

As explained above, in the present invention, the transparent tablet 2 is placed on the display unit 1, characters and figures are inputted using the input pen 3, and the position of the input pen 3 is detected by the position detection unit 5 and displayed. At the same time, the interpolation processing section 6 performs interpolation processing based on the trajectory of the input pen 3 to find a position close to the actual pen-down position and displays it. It has the advantage of correcting partial omissions and correctly displaying human-generated characters and figures. Therefore, it becomes possible to input fine characters and figures such as kanji correctly.

[Brief explanation of drawings]

Fig. 1 is a principle block diagram of the present invention, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is an explanatory diagram of interpolation processing, Fig. 4 is a processing flowchart of the embodiment of the present invention, and Fig. 5 6 is an explanatory diagram of the character/figure input device, FIG. 6 is an explanatory diagram of the input pen and input section, FIG. 7 is a block diagram of the position detection section, FIG. 8 is a diagram for measuring handwriting characteristics, and FIG. 9 is the position of the input pen. Detection operation explanatory diagram, FIG. 10 is a display explanatory diagram. 1.15.21 is a display unit, 2.17.22 is a tablet, 3, 18.23 is an input pen, 4 is a control unit, 5 is a position detection unit, 6 is an interpolation processing unit, 11 is a processor, 12 is a main unit Memory, 13 is a display control device, 14 is a display memory, 1
6 is a tablet control device, and 19 is a data bus.

Claims (1)

[Claims] A transparent tablet (2) is placed on the display section (1), characters and figures are inputted onto the tablet (2) using an input pen (3), and the text on the tablet (2) is In the character/figure input processing method in which the position of the input pen (3) is detected by the position detection section (5) of the control section (4) and displayed on the display section (1), the control section (4) , the position detection section (5)
An interpolation processing unit (6) is provided to interpolate the trajectory determined by the input pen (3) determined by the position detection unit (5).
) on the tablet (2), the interpolation processing unit (6) determines the position where the input pen (3) actually contacts the tablet (2) through interpolation processing;
A character/graphic input processing method characterized by displaying on the display section (1).