JPH0727435B2 - Handwritten image input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is mainly used in a picture image communication device for transmitting and receiving a handwritten picture image together with voice using a general telephone line. The present invention relates to a handwritten image input device.

[Prior art]

A drawing image communication device capable of transmitting and receiving a handwritten drawn image together with a voice using a general telephone line has been developed. By the way, an input device for inputting a handwritten drawn image is required in this type of drawn image communication device, but the conventional handwritten drawn image input device is a pressure-sensitive type having a configuration shown in the schematic cross section in FIG. The drawing pad was mainly used. That is, in the conventional pressure-sensitive drawing pad, the resistance sheet 3 is provided on the upper and lower sides of the pressure-sensitive sheet 37, which becomes substantially conductive due to a decrease in electric resistance value when pressure is applied.
6, 38 are arranged, and the input surface protection film 31 is arranged on the upper surface of the upper resistance sheet 36. And double resistance sheet
36 and 38 are combined so that the directions in which the resistance values increase are orthogonal to each other, and a constant voltage is applied to each of the orthogonal ends, and an input pen (normal pencil, ballpoint pen) is applied from above the input surface protection film 31. Etc.), a pressure sensitive sheet 37 at that position is conducted by the contact pressure of the input pen, and the resistance sheets 36 and 38 on the upper and lower sides are short-circuited. The position of the input pen on the drawing pad is detected by detecting the change in the voltage value of both resistance sheets 36 and 38 at this time by the detection circuit 30.

[Problems to be solved by the invention]

By the way, generally, when a person writes a character or draws a figure, especially when drawing a continuous line, if the writing speed is a little faster, the writing pressure may be insufficient, and the drawn line may be faint or blurred. On the other hand, the pressure-sensitive sheet of the drawing pad as described above becomes substantially conductive only when a certain amount of pressure is applied. When the writing pressure is insufficient like
On the input surface protection film 11, so-called "interruption" occurs in which a blank is drawn in the middle of a drawn line that is drawn continuously and should be input as a continuous line.

[Means for solving problems]

The present invention has been made in view of the above circumstances,
A film switch that uses a pressure-sensitive sheet that overlaps the pressure-sensitive sheet of a conventional drawing pad and does not conduct when contacted by human fingers is used, but conducts at a pressure lower than the conduction pressure of the pressure-sensitive sheet is adopted. There is. By adopting such a configuration, even when the writing pressure of the drawing pen being drawn on the drawing pad falls below the level at which the pressure-sensitive sheet becomes non-conductive, the drawing by the drawing pen is performed by the conduction of the film switch. That is, it becomes possible to detect that the image input is continued. Therefore, in such a case, the image processing may be performed assuming that the drawing is continuously performed between the position of the input pen detected next time. It is an object of the present invention to provide a handwritten drawing image input device which can prevent the disconnection of the drawing line, which often occurs in the conventional pressure-sensitive drawing pad, by adopting such a configuration.

The present invention provides a pressure-sensitive sheet that conducts by the contact pressure of a handwriting input pen, a position signal that indicates a conduction position of the pressure-sensitive sheet, and an input position detection that outputs a pen-down signal that indicates that the input pen is in contact. In a handwritten drawing image input device including a circuit and a processing circuit that performs an image input process based on the position signal, a pressure smaller than a pressure overlaid on the pressure-sensitive sheet and conducted by the pressure-sensitive sheet and a finger. A film switch using another pressure sensitive sheet that conducts at a pressure higher than the contact pressure, a detection circuit that outputs a detection signal to the processing circuit when the film switch is conducting, and an image input by the input pen Is performed and both the pen down signal and the detection signal are applied to the processing circuit, and then only the pen down signal is not applied,
And a unit for performing an image input process based on position signals immediately before and immediately after the period when the detection signal is not applied.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing an embodiment thereof.

FIG. 1 is a schematic diagram showing the configuration of a handwritten drawn image input device according to the present invention.

In the figure, reference numeral 1 is a pressure-sensitive drawing pad, and a schematic cross section thereof is shown in FIG. The pressure-sensitive drawing pad 1 includes an input surface protection film 11 on the uppermost surface and a resistance sheet on the lower half.
16, the structure consisting of the pressure sensitive sheet 17 and the resistance sheet 18 is similar to the conventional general pressure sensitive drawing pad, but in the device of the present invention, the input surface protective film 11 and the resistance sheet 16 of the uppermost surface In the meantime, the pressure sensitive sheet 13 is connected to the electrode sheets 12 and 14
The film switch 10 sandwiched from above and below is disposed so as to be electrically insulated from the lower half resistance sheet 16 by the insulating sheet 15. The pressure-sensitive sheet 13 used in the film switch 10 has a pressure required for its conduction to be considerably lower than that of the pressure-sensitive sheet 17, but is set higher than the contact pressure of a human finger or the like. Therefore, both electrode sheets 12,14
Is not conductive when touched by human fingers, etc., but of course with the writing pressure when proper drawing is performed with the input pen,
Even when the writing speed of the input pen during drawing is increased and the writing pressure is reduced to such an extent that the pressure-sensitive sheet 17 does not conduct, the current is conducted and the electrode sheets 12 and 14 are short-circuited.

Resistance sheet 16 and pressure sensitive sheet 17 in the lower half of the insulation sheet 15
An input position detection circuit 22 for detecting a voltage change of both the resistance sheets 16 and 18 to detect an X coordinate and a Y coordinate voltage is connected to the same constituent portion as that of the conventional pressure sensitive drawing pad composed of the resistance sheet 18 and the resistance sheet 18. Has been done. This input position detection circuit 22
Indicates that the X-coordinate and Y-coordinate voltage signals representing the position of the input pen on the drawing pad 1 and the pressure sensitive sheet 17 are conducting based on the voltage changes of the resistance sheets 16 and 18, in other words, by the input pen. The first pen-down signal PDS1 indicating that drawing is being performed is output, and these output signals are given to the processing circuit 3.

A detection circuit 21 for detecting conduction of the pressure sensitive sheet 13 is connected to both electrode sheets 12 and 14 of the film switch 10 above the insulating sheet 15, and the detection circuit 21 detects the sense of the film switch 10. The pressure sheet 13 conducts and both electrode sheets 1
A second pen down signal PDS2 indicating whether or not 2 and 14 are short-circuited
And the second pen-down signal PDS2 is supplied to the processing circuit 3.

The detection circuit 21 described above and the input position detection circuit 22 described above
The detecting section 2 is constituted by.

The operation of the device of the present invention configured as described above will be described with reference to the flowchart of FIG. 2 and the timing chart of FIG. 3 showing the processing contents of the processing circuit 3.

First, the flag is reset. Then, when the input of the drawn image by the input pen is started on the drawing pad 1 (Fig. 3), the film switch 10 is turned on first so that the pen down signal PDS2 turns to a high level (Fig. 3).
After a short delay, the pressure sensitive sheet 17 becomes conductive and the pen down signal PDS1 also turns to high level (FIG. 3). Then, at the sampling timing T0, the processing circuit 3 reads the X, Y coordinate signals supplied from the input position detection circuit 22 and performs a predetermined process. Since the flag has been reset, the processing circuit 3 returns to the step of checking the state of the pen-down signal PDS2 after waiting for the next sampling timing T1.

By repeating the above-described series of processing at each sampling timing, the position of the input pen on the drawing pad 1 at each sampling timing is sequentially detected, and the data is stored as a continuous drawing line in a memory (not shown), or After being subjected to predetermined processing by a data processing device (not shown), it is transmitted to the other party through a telephone line.

Now, for example, when the writing speed of the input pen during image input is slightly increased and the writing pressure is reduced to such an extent that the pressure-sensitive sheet 17 does not conduct, the pen down signal PDS1 turns to a low level (FIG. 3 or). At this time, when the pen down signal PDS2 also turns to the low level (FIG. 3), the input of the drawn image by the input pen is stopped, specifically, the input pen touches the pressure-sensitive drawing pad 1. Not in a state (3rd
In this case, the process is returned to the step of resetting the flag.

On the other hand, when the pen down signal PDS2 maintains the high level even though the pen down signal PDS1 has changed to the low level (FIG. 3), the input of the drawn image by the input pen itself is stopped. However, the writing pressure was reduced for some reason. In this case, the processing circuit 3 causes the pen down signal PDS1 to turn to the high level again and both pen down signals PDS1 and PDS2 to turn to the high level (Fig. 3), or the pen down signal PDS2 to turn to the low level and both pen down signals. The states of the pen-down signals PDS2 and PDS1 are checked at each subsequent sampling timing until the signals PDS1 and PDS2 both turn to low level (described above). As a result, if the pen-down signal PDS2 also goes low and both turn to low (FIG. 3,), it is determined that the input of the drawn image by the input pen has been stopped, and the processing circuit 3 resets the flag. Return processing. However, if the pen-down signal PDS1 goes high and both turn to high (FIG. 3), after the flag is set, the process proceeds to the step of reading the X, Y coordinate signals. After that, since the flag is set, the X and Y coordinates read in the processing at the immediately preceding sampling timing T4 and the previous time, specifically, the pen down signal P
The processing is performed by, for example, known straight line and curve interpolation so that the drawn line between the X and Y coordinates read in the processing at the sampling timing T2 immediately before the DS1 changes to the low level is connected.

〔effect〕

As described above in detail, according to the present invention, when an image is input to a drawn image communication device by a handwritten drawn image input device, when the writing speed is conventionally high and the writing pressure is insufficient, ,
Although no image input is detected and a continuous line is drawn on the input surface of the input device, a line that is cut off in the middle as image data is input and is also transmitted to the other party. Such inconvenience is avoided.

In the above embodiments, the present invention is applied to the drawn image communication device, but the present invention can of course be applied to, for example, a handwriting input device of a word processor.

[Brief description of drawings]

The drawings show the embodiments of the present invention. FIG. 1 is a schematic diagram showing the configuration of a handwritten drawing image input device according to the present invention, and FIG. 2 is a flow chart showing the processing contents of its processing circuit.
FIG. 3 is a timing chart of the same, and FIG. 4 is an explanatory diagram of a conventional technique. 1 ... Pressure-sensitive drawing pad, 3 ... Processing circuit 10 ... Film switch, 11 ... Input surface protection film,
12,14 …… Electrode sheet, 13 …… Pressure sensitive sheet, 15 …… Insulation sheet, 16,18 …… Resistance sheet, 17 …… Pressure sensitive sheet

Claims (1)

[Claims] 1. A pressure-sensitive sheet that conducts by the contact pressure of a handwriting input pen, an input position that outputs a position signal indicating the conductive position of the pressure-sensitive sheet, and a pen-down signal indicating that the input pen is in contact. In a handwritten drawing image input device including a detection circuit and a processing circuit that performs an image input process based on the position signal, a pressure smaller than a pressure overlaid on the pressure-sensitive sheet and conducted by the pressure-sensitive sheet and a finger. A film switch using another pressure-sensitive sheet that conducts at a pressure higher than the contact pressure of, a detection circuit that outputs a detection signal to the processing circuit when the film switch is conducting, and an image by the input pen After the input is made and both the pen down signal and the detection signal are given to the processing circuit,
A means for performing interpolation processing as continuous drawing lines based on the position signals immediately before and immediately after the period when the pen down signal is not given, when only the pen down signal is not given. Handwritten drawing image input device characterized by.