JP5723697B2 - Display device with handwriting input function - Google Patents

Description

  The present invention relates to a display device with a handwriting input function that detects a change in position touched by a display unit as a handwritten locus and displays a line at a corresponding location.

In recent years, display devices such as liquid crystal display devices have become thinner, higher in image quality, larger in size, and lower in cost, and new applications have been created.
For example, there is an application to a smart phone or an electronic book terminal which can be said to be an advanced form of a portable information terminal. There are also applications for information or digital signage that can be said to be a development of conventional posters and signs. Furthermore, a system that can be said to be a development of a so-called electronic blackboard using a large display device equipped with a touch panel or the like has been proposed.

As described here, there are various uses for realizing an intuitive operation by the user by detecting an input on a display device using a sensor such as a touch panel. Some of them are compatible with handwritten input, such as an electronic blackboard. In addition, the information display and the display device for digital signage can be used not only to detect a touch on a button displayed on the screen but also to input a handwritten character with a finger.
In such handwriting input, it is normal to display a line corresponding to the location touched by the display unit to indicate that the user input has been accepted. Further, it is usual to provide a so-called eraser function for erasing or correcting when there is a writing error. However, in order to use this eraser function, it has been conventionally necessary to switch the input mode.

Various techniques related to handwriting input have been proposed in the field of portable information terminals. Regarding the eraser function, a technical point is known in which a character is deleted by writing a gesture on a target character (see, for example, Patent Document 1).
Also, there is a technology for detecting the size of the area touched by the display unit and switching from the function of drawing a line as a pen to the function of erasing a line as an eraser when the size of the pen is larger than that of a dedicated pen for input. .

JP-A-6-149467

  In handwriting input using a large display device such as an electronic blackboard, if the user makes a mistake in writing a character or the like, it tends to scrape off the wrong place with a hand or finger with the feeling of a familiar blackboard or white board. . However, conventionally, in order to use the eraser function, an operation for switching the mode is required. If the user does not know it or knows it and rubs it with a finger when trying to erase it, the display device recognizes the operation of rubbing with the finger as a writing action. As a result, a line is drawn at the location where the user rubbed, and the process according to the user's intention to erase the character or the like is not performed.

In this way, an electronic blackboard or the like should emphasize intuitive and simple operation so that anyone can easily use it. When using the eraser function, it is necessary to switch functions one by one. That is, since the operation for instructing erasure is not intuitive, the user needs knowledge and familiarity. Moreover, even if the operation is learned, there is a problem that the operation related to the instruction is complicated.
The present invention has been made in view of the above circumstances, and provides a display device that allows a user to instruct erasure of a line displayed on a display unit by an intuitive and simple operation.

  The present invention provides a display unit that can display handwritten characters and handwritten line drawings, a detection unit that detects a position touched by the display unit as time passes, and a detection unit that detects the position as a handwritten locus. Control to display a line corresponding to the handwriting trajectory on the display unit and to execute processing associated with the gesture when it is determined that the pattern predetermined as a gesture matches the handwritten trajectory And the gesture includes an erasing gesture for erasing a line already displayed on the display unit, and when the handwriting locus is newly detected, the handwriting locus is an erasing gesture pattern. When it is determined that the handwriting locus coincides with the erase gesture, the line overlapping the handwriting locus is erased. When it is determined that the over emissions provides handwriting input-capable display device, characterized in that to display the line overlapping the handwriting trajectory.

  In this invention, when a handwriting locus is newly detected, the control unit erases a line that overlaps the handwriting locus when it is determined that the handwriting locus matches the pattern of the erasing gesture, and the handwriting locus is an erasing gesture. When it is determined that the pattern is different, the line overlapping the handwritten locus is displayed, so that the line already displayed on the display unit can be erased by an intuitive instruction mode called gesture. Since there is no need to perform the operation of switching to the eraser function mode as in the prior art, the operation is simple.

  In other words, as with a conventional blackboard or white board, the user can erase a line that the user wants to erase by rubbing the line already displayed on the display unit with a finger, and processing according to the user's intention is realized. The

In the present invention, the handwritten character is a character input by the user freehand. It does not matter whether the mode displayed on the display unit is a character consisting of a line as drawn by the user freehand or a character displayed by a predetermined font by performing handwritten character recognition.
The handwritten line drawing is an image composed of lines input by the user freehand. It does not matter whether the mode displayed on the display unit is a line as drawn by the user freehand or a line that is displayed after being shaped to some extent such as correction of distortion.

The display unit displays information, and displays at least the above-mentioned handwritten characters and handwritten line drawings. In addition, a video or an image corresponding to the input signal or data stored in the memory may be displayed. Specific examples thereof include an information display using a liquid crystal panel and an electronic blackboard using a liquid crystal panel.
The detection unit detects that the display unit has been touched and a touched location, and detects a change in the location with time. The specific mode is, for example, a touch panel sensor and a processing circuit that processes the signal. The detection principle may be any system such as electrostatic or optical.

  The handwriting trajectory is a history of positions where the display unit is touched with a user's fingers or a touch pen. The word “trajectory” is used, but the handwritten trajectory itself is not visible. However, the control part which concerns on this invention can display a line in the location where the handwritten locus | trajectory was drawn among the display parts. In that case, the displayed line shows a handwritten locus. However, in a mode in which handwritten character recognition is performed and characters in a predetermined font are displayed, the control unit displays a line at a position corresponding to the handwritten locus in the display unit during the period after the handwriting input. However, after character recognition, a character in a predetermined font is displayed instead of the line. The same applies to shaping a line drawn freehand.

In addition, a gesture is a device in which a specific pattern is associated with a specific instruction in advance in an apparatus having a handwriting input function such as an information portable terminal. Then, when the corresponding pattern is drawn, processing is performed assuming that an instruction associated with the pattern is given.
Further, the location corresponding to the locus specifically refers to a pixel corresponding to a location touched by the display unit when the display unit is composed of a plurality of pixels arranged vertically and horizontally. The trajectory can be said to be a trace where the part touched by the display unit has moved with time. However, since the area covered by one pixel is very small, a plurality of pixels correspond to a place touched at a certain point in time. Furthermore, a larger number of pixels correspond to a trajectory as a trace of the location moving with time.

It is explanatory drawing which shows the external appearance of the display apparatus of this invention. It is a block diagram which shows the electrical structure of the display apparatus 11 shown in FIG. It is the 1st explanatory view showing contents which a control part concerning this invention displays on a liquid crystal display according to operation. It is the 2nd explanatory view showing contents which a control part concerning this invention displays on a liquid crystal display according to operation. It is a 1st flowchart which shows the process which the control part which concerns on this invention performs. It is a 2nd flowchart which shows the process which the control part which concerns on this invention performs. It is a 3rd flowchart which shows the process which the control part which concerns on this invention performs. It is a 4th flowchart which shows the process which the control part which concerns on this invention performs. It is a 1st explanatory view showing an example of a mode in which a control part concerning this invention determines a candidate for erasure. It is the 2nd explanatory view showing the example of the mode in which the control part concerning this invention determines the candidate for erasure.

Hereinafter, preferred embodiments of the present invention will be described.
The control unit determines whether or not the handwriting trajectory matches the pattern of the erasure gesture only when the period from the start of drawing the handwritten trajectory to the end of drawing is within a predetermined time, and is drawn within the predetermined time. When there is not, it may be made not to use an erase gesture. In this way, the line can be erased when it is determined that the erase gesture matches the pattern and that the line is drawn within a predetermined time after the line is drawn. In other words, since it is determined that the writing is normal writing based on a combination of morphological and temporal conditions, a process more in line with the user's intention is realized.
The pattern of the erase gesture may be a bent line having a predetermined number of turns or more. In this way, like a conventional blackboard or white board, the operation of rubbing the display portion of the part to be erased with a finger is detected as a bent line written with a single stroke, that is, a folded line including a folding point, and an erase gesture and Judgment can be made. That is, when trying to erase a line drawn on a conventional white board or blackboard, the user usually rubs to draw a serrated bent line on the white board or blackboard on which the line has already been drawn, The control unit can erase the line according to the user's intention in response to the detection of the intuitive or reflective operation by the user.

  Alternatively, the detection unit detects a handwritten trajectory having a thickness, and the control unit erases a portion of the line determined to intersect the handwriting trajectory that overlaps the handwritten trajectory having the thickness and does not overlap. The portion may not be erased. In this way, the user erases the line so as to erase the part that overlaps the handwritten trajectory and leaves the other part by drawing the handwritten trajectory of the erase gesture so as to intersect a part of the already drawn line. can do. Therefore, lines can be erased at intervals similar to those of conventional white boards and blackboards.

  In addition, the control unit may erase the entire line connected to the portion determined to overlap the handwriting trajectory. In this way, even if the handwriting trajectory of the erasing gesture is not drawn over the entire drawn line, the control unit erases the entire line connected to the portion overlapping the handwritten trajectory. You can erase the entire line with.

  Alternatively, the detection unit may be configured to erase a portion that overlaps the handwriting locus having the thickness and does not erase a portion that overlaps the handwriting locus having the thickness, or overlaps the handwriting locus. The selection of whether to delete the entire line connected to the determined portion may be accepted, and the line may be deleted in the selected mode. In this way, the control unit can switch whether to erase only the part where the line overlaps the handwritten locus, or to erase the entire line using the erase gesture, according to the user's selection.

In addition, the control unit determines whether the handwriting trajectory coincides with the erasure gesture only when the time from when the handwriting trajectory starts to be drawn to when the handwriting trajectory is finished is shorter than a predetermined period, When it is longer than the period, a line may be displayed at a location corresponding to the handwritten locus. In this way, it is possible to more reliably discriminate between an operation for reflecting off a line and an operation for drawing a line based on the time from the start of drawing a handwritten locus to the end of drawing.
Preferred embodiments of the present invention include combinations of any of the plurality of embodiments shown here.

Hereinafter, the present invention will be described in more detail with reference to the drawings. In addition, the following description is an illustration in all the points, Comprising: It should not be interpreted as limiting this invention.
≪Configuration of display device≫
FIG. 1 is an explanatory view showing the appearance of the display device of the present invention. As shown in FIG. 1, the display device 11 of the present invention includes a liquid crystal display 13 as a display unit and a touch panel 15 as a detection unit arranged on the liquid crystal display 13. Furthermore, a stand 17 for pointing the liquid crystal display 13, a control unit, and a control unit (not shown in FIG. 1) as a storage unit are provided. The control unit is disposed on the back surface of the liquid crystal display 13.

  The touch panel detects the position when the user's finger or the input pen touches the screen of the liquid crystal display 13. When a plurality of positions are touched simultaneously, each position can be detected. When the position changes with time, it is detected as a handwritten locus. When a wide area is touched, the area is detected. For example, an area corresponding to the thickness of the pen tip of the input pen is detected. Therefore, the thickness of the handwriting locus differs when the thickness of the pen tip is different.

The stand 17 is provided with a caster so that it can be moved as necessary. However, as a different aspect, the display device 11 may not be provided with a stand and may be fixed to a wall or a column.
FIG. 2 is a block diagram showing an electrical configuration of the display device 11 shown in FIG. As shown in FIG. 2, the display device 11 includes a liquid crystal display 13, a touch panel 15, a control unit 19, and a storage unit 21. The hardware configuration of the control unit 19 includes a CPU that executes a control program stored in the storage unit 21, a RAM that provides a work area for the CPU, and a display control circuit that generates a video signal to the liquid crystal display 13. Become. Furthermore, it includes an input / output circuit and a timer to which signals between the liquid crystal display 13 and the touch panel 15 are connected. The hardware configuration of the storage unit 21 is a nonvolatile memory that stores a control program to be executed by the CPU, definitions of patterns and processes related to gestures, display data of the liquid crystal display 13, and other data.

  Further, as a functional configuration of the control unit 19, a display control unit 19a and an input detection unit 19b are provided. The display control unit 19 a performs control to display information on the liquid crystal display 13. For example, when HTML data constituting a web page is input, characters and images corresponding to the HTML data are displayed on the liquid crystal display 13. More specifically, the display control unit 19a includes a graphic drawing unit and a position determining unit. The graphic drawing unit creates and deletes a graphic to be displayed on the liquid crystal display 13. The position determination unit determines the position, size, and range for displaying an object such as a handwritten line.

  The input detection unit 19 b detects a user operation based on a detection signal from the touch panel 15. More specifically, the input detection unit 19b includes a position detection unit, a contact detection unit, a size detection unit, a gesture detection unit, and a time measurement unit, that is, a timer. The position detection unit acquires the coordinates of the position where the touch panel 15 is touched. The contact detection unit detects the presence or absence of a touch on the touch panel 15. The size detection unit detects the size of the touched area. The gesture detection unit detects the coincidence when the handwritten locus coincides with a predetermined gesture pattern. The time measurement unit starts time measurement when a touch on the touch panel is made, continues measurement while the touch continues, and stops measurement when the touch disappears.

  As a functional configuration of the storage unit 21, an input coordinate storage unit 21a, a graphic drawing information storage unit 21b, and a time storage unit 21c are provided. The input coordinate storage unit 21a stores the coordinates of the position where the touch panel 15 is touched as input coordinates. As the touched position moves, a plurality of input coordinates are associated and stored. A series of input coordinates represents the shape of the handwritten locus. The graphic drawing information storage unit 21 b stores information related to objects to be displayed on the liquid crystal display 13. The time storage unit 21c stores time data measured by the time measurement unit.

≪Display control≫
3 and 4 are explanatory diagrams illustrating examples of contents displayed on the liquid crystal display 13 by the control unit 19 in accordance with a user operation. As shown in FIGS. 3 and 4, the display area of the liquid crystal display 13 is roughly divided into a tool bar 33 and a work area 35. The toolbar 33 displays instructions received by the display device as a plurality of buttons. Examples of the buttons are as follows. There is an “end” button for instructing to end the application as an electronic blackboard. There is also an “Open” button for opening the file of the electronic blackboard application. Further, there is a “Save” button for saving the file. And there is a “pen” button that draws a line. In addition, there is an “Eraser” button that erases the drawn line. There is also a “Select” button for selecting the drawn object. There is a “print” button for printing the work area 35. There is also a “Setting” button for making various settings. When each button is touched by the user, the control unit 19 recognizes the touched button based on the detection signal of the touch panel 15 and executes a predetermined instruction for the button.

When the user touches the “pen” button and writes a character in the work area 35 using an input pen (not shown), the touch panel 15 detects a change in the position touched by the pen tip of the input pen and the position with time. The control unit 19 that has received a signal from the touch panel 15 determines a change in the detected position, that is, a handwriting locus. Then, it is determined whether or not the handwritten trajectory matches a predetermined gesture pattern.
When it coincides with the gesture, the control unit 19 executes a predefined process for the gesture. An example of a gesture is line erasure as will be described later. On the other hand, when the handwriting trajectory does not match any gesture, the control unit 19 controls the liquid crystal display 13 to display a line corresponding to the handwriting trajectory. As a result, characters are drawn as handwritten lines. Preferably, the control unit 19 stores each line, that is, each handwritten locus as an object in the storage unit 21.

When the user touches the “eraser” button and recognizes that the work area 35 has been wiped with the input pen or finger based on the detection signal from the touch panel 15, the control unit 19 detects the wiped portion. If a line is drawn, delete that line. That is, the pixel data of the wiped portion is initialized so that nothing is drawn.
FIG. 3A shows an example in which the control unit 19 displays handwritten characters corresponding to the handwriting locus in the work area 35. (B) shows a state in which the user has further written the characters “to”. At this time, it is assumed that the user notices that the last written “to” character is incorrect. Of course, if the character “to” is wiped after touching the “eraser” button, the control unit 19 erases that portion. However, in this case, it is assumed that the user wipes the character “to” without touching the “eraser” button.

  FIGS. 3C, 4A, and 4B show the display of the work area 35 at that time. FIG. 3C shows a state immediately before the user traces the character “TO”, and the finger 31 is just above the character “TO”. FIG. 4A shows a state immediately after the tip of the finger 31 moves in the direction of arrow A from the top to the bottom and the character “to” is wiped off. At this time, the control unit 19 recognizes the part touched by the tip of the finger 31 based on the detection signal from the touch panel 15 and causes the liquid crystal display 13 to display a line corresponding to the handwritten locus. FIG. 4B shows a state immediately after the finger 31 is moved in the direction of the arrow A ′ from the lower side to the upper side, and the characters “to” are wiped off.

  FIG. 4C shows a state immediately after the tip of the finger 31 is further moved in the direction of the arrow A from the upper side to the lower side and the character “to” is wiped off. At this time, the control unit 19 recognizes based on the detection signal from the touch panel 15 that it has been repeatedly touched at almost the same position. Then, it is determined that this pattern corresponds to the erase gesture pattern stored in the storage unit 21. Based on the determination, the control unit 19 erases the line drawn to overlap the character “to” at the timings of FIGS. 4A and 4B and the line of the character “TO” overlapping the line. That is, the line of the portion wiped at the timings of FIGS. 4A and 4B is erased.

Here, the control unit 19 may leave the unwiped portion without erasing. However, as another aspect, a handwritten line object that at least partially overlaps the wiped portion may be erased in units of objects. As yet another aspect, a line continuous with a handwritten line that at least partially overlaps the wiped part may be erased. According to this aspect, for example, the character “to” is erased from the entire character “to” because the lines constituting the character are continuous. On the other hand, for example, in the case of the character “DO”, the two lines of “TO” and the cloud point are not continuous and are isolated, so if only the “TO” part is wiped, the cloud point 2 Leave the lines of the book without erasing them.
Note that any one of the modes may be selected by the user's selection. The following can be considered as means for performing the selection. When the “setting” button in the toolbar 33 is touched, the control unit 19 executes the setting menu in response thereto. In the setting menu, a menu for accepting the selection is prepared. When the user makes a selection while viewing the menu screen displayed in the work area 35, the control unit 19 recognizes the user's selection based on the detection signal from the touch panel 15. After ending the setting menu according to the user's instruction, the control unit 19 performs an erasing process according to the selected mode.

≪Flowchart≫
5-8 is a flowchart which shows the process which the control part 19 performs. A processing procedure will be described with reference to the flowchart. In addition, although the flowchart has shown the aspect in which the location touched simultaneously is only one location, when extending this to multiple locations, if the process of FIGS. 5-8 is processed in parallel by the number of those locations. Good. In addition, although the flowchart describes only the drawing process sequentially in order to make the features of the present invention easier to understand, the control unit 19 can perform other processes such as monitoring whether or not the button of the toolbar 33 has been pressed. Is done by multitasking.

First, in FIG. 5, the control unit 19 monitors whether or not a new line has started to be drawn based on the detection signal from the touch panel (step S11). The fact that a new line has been drawn means that the control unit 19 has determined that a new position that is not continuous with any handwriting locus has been touched.
When it is determined that a new line has started to be drawn (Yes in step S11), the control unit 19 next sets 1 as an initial value to a variable n for counting the number of lines divided by the turning point when a turning line is drawn. Is set (step S13). The variable n is secured as a specific storage area in the RAM that provides the work area. Then, a timer for obtaining a time from the start to the end of drawing when a wrapping line is drawn is started (step S15).
Furthermore, the control part 19 calculates | requires the touched position based on the detection signal obtained from the touch panel at the time of performing judgment of the said step S11 (step S17). The position is stored in the storage unit 21 as the starting point coordinates (step S19).

  Subsequently, the control unit 19 checks whether or not the touch is continued at the present time based on the detection signal from the touch panel (step S21). If the touch is not continued (No in step S21), the routine returns to step S11 and waits for a new line to be drawn. On the other hand, when the touch is continued (Yes in step S21), the coordinates of the position touched at the present time are obtained (step S23). This is because when the touched position is changed, the position is tracked. If the obtained coordinates are different from the previous coordinates, the obtained coordinates are stored in the storage unit 21 in association with the previous coordinates (step S25). A series of coordinates stored in the storage unit 21 becomes a handwritten locus. Then, a line connecting the previous coordinate is displayed in the work area 35 (step S27). A series of displayed lines becomes a line corresponding to the handwritten locus.

  Subsequently, the control unit 19 checks whether or not the value of the variable n that stores the number of lines divided by the switchback (number of folded lines) is 3 (step S29). If the variable n is 3, it is determined that there is a possibility of an erase gesture (Yes in step S29). Then, the routine proceeds to step S41 shown in FIG. 7, and executes a process related to determination as to whether or not it is an erase gesture. Of course, the value “3” of the variable n is an example of a threshold value. The threshold value may be a value other than “3” as long as the drawing of the broken line and the operation to erase the drawn line can be distinguished. In this flowchart, only the process of the erase gesture according to the feature of the present invention is shown, and the processes related to other gestures are omitted. However, when recognizing other gestures, it should also be determined at this portion whether the pattern and the handwriting trajectory match.

  On the other hand, if the value of the variable n is not 3 in Step S29 (No in Step S29), the control unit 19 makes the movement direction with the previous coordinate in the direction opposite to the previous movement direction. It is checked whether or not (step S31). That is, it is checked whether a new switchback has been performed. Here, even if the opposite direction is not a reverse direction, if the angle is within a certain range, it is determined to be switchback. An example is a range of 135 ° or more and 225 ° or less.

  When it is determined that the switchback is not performed (No in step S31), the routine returns to the above-described step S21 and loops. In this loop processing, the control unit 19 stores the handwritten trajectory in the storage unit 21 and displays the corresponding line. On the other hand, if it is determined that the switchback is new (Yes in step S31), the routine proceeds to step S33 in FIG.

  In step S33, the control unit 19 checks the value of the variable n that stores the number of folded lines. When the variable n is 2, two lines divided at the turn-back point, that is, one reciprocal line, are drawn, so the current coordinates and the start point coordinates are compared (step S35). If the position is not within the predetermined range from the starting point coordinates and is away from the starting point coordinates, it is determined that it does not correspond to the erasing gesture (Yes in Step S35), and the routine returns to Step S11 described above. That is, the erase gesture determination is reset, and a process for obtaining a handwritten locus is started. If it is within a predetermined range from the starting point coordinates, the value of the variable n is incremented by 1 (step S39), the process returns to the above-described step S21, and the process of obtaining the handwritten locus is continued.

On the other hand, if it is determined in step S33 that the value of the variable n is not 2, that is, if the value of the variable n is determined to be 1, the coordinates at which the switchback is performed first are stored as the coordinates of the turning point. 21 (step S37). Then, the value of the variable n is incremented by 1 (step S39), the process returns to the above-described step S21, and the process for obtaining the handwritten locus is continued.
If it is determined in step S29 described above that the value of the variable n is 3, the control unit 19 executes the following processing. First, the current coordinates are stored in the storage unit as end point coordinates (step S40). Then, the end point coordinates are compared with the position of the turning point coordinates stored in the storage unit 21 at the time of the first switchback (step S41). This comparison corresponds to step S35 described above. If the end point coordinate is not within the predetermined range from the turn point coordinate and is away from the end point coordinate, it is determined that the end point coordinate does not correspond to the erase gesture (No in step S41), and the routine returns to step S21 described above. That is, it is determined that the gesture is not an erasing gesture, and the process of obtaining a handwritten locus is continued.

If within the predetermined range from the turning point coordinates (Yes in step S41), the control unit 19 checks the timer and confirms whether or not it is within the predetermined time after the line is started to be drawn (step S43). If it is not within the predetermined time, it is determined that the gesture is not an erase gesture, and the routine returns to step S11 described above. That is, the determination of the erase gesture is reset and processing for obtaining a handwritten locus is newly started.
On the other hand, if it is within the predetermined time, the control unit 19 stores the current coordinates as end point coordinates in the storage unit 21 (step S44). Next, the control part 19 calculates | requires the distance between a starting point coordinate and an end point coordinate, and compares it with a predetermined distance. If it is less than the predetermined distance (No in step S45), it is determined that the erase gesture is elliptical. Then, the routine proceeds to step S53 in FIG. The predetermined distance may be determined in advance such as 10% of the distance between the start point and the end point.

  On the other hand, if both are equal to or longer than the predetermined distance (Yes in step S45), the control unit 19 determines that the erasing gesture is a folded line shape, and executes a process associated with the folded line shaped erase gesture. That is, a straight line connecting the start point and the end point is defined as a reference direction, and a direction perpendicular thereto is defined as a width direction. Then, the distribution in the width direction of each part of the return line determined as the erasing gesture, that is, each coordinate stored in the storage unit 21 is obtained. If each coordinate is within a predetermined distance in the width direction, it is determined that the wrapping line traces the same part and is finally a true erasing gesture (Yes in step S47). Then, the routine proceeds to step S49.

  On the other hand, if each coordinate is not within the predetermined distance in the width direction, it is determined that the drawn folding line does not trace the same portion, and the routine returns to step S11. Here, a message indicating that it is not an erase gesture may be displayed on the display device 11. In this case, the control unit 19 does not perform the erasing process in response to the erasing gesture. Then, since the line is displayed in the above-described step S27, the return line is drawn.

Note that if the fold line continues to be drawn even after the routine returns to step S11, the control unit 19 newly determines an erase gesture.
In step S49, the control unit 19 extracts a region belonging to the handwritten locus drawn so far by connecting the start point and the turning point. There are several possible ways of extracting the region. This will be described later. The control unit 19 erases the line drawn in the extracted area. That is, the handwritten locus is deleted, and the line drawn so as to intersect the handwritten locus is deleted (step S51). Then, the routine returns to step S11.

On the other hand, when it is determined in step S45 described above that the erasure gesture is elliptical, the control unit 19 executes the following process. First, the control unit 19 searches for the position drawn on the outermost side among the coordinates of the handwritten trajectory stored in the storage unit. In order to simplify the processing, the coordinates of the uppermost, lowermost, leftmost, and rightmost points are obtained as representatives of the outermost region (step S53). Further, out of the coordinates of the line stored in the storage unit, the vertical and horizontal coordinates indicating the innermost area of the drawn line are obtained (step S55). In order to simplify the processing, the upper, lower, left, and right inner points corresponding to the uppermost, lowermost, leftmost, and rightmost points obtained in step S53 described above are obtained as representatives. Then, based on the coordinates of the four representative points of upper, lower, left, and right, it is determined whether the difference in size between the outermost region and the innermost region is within a threshold value (step S57).

  The threshold value may be determined in advance as, for example, the ratio of the distance between the inner upper and lower points to the distance between the uppermost point and the lowermost point. Alternatively, it may be determined in advance as a ratio of the distance between the inner left and right points with respect to the distance between the leftmost point and the rightmost point. It may be determined in advance as a combination of both.

  As a result of the determination, if the difference in size between the outermost area and the innermost area is not within the threshold value, it is determined that the drawn elliptical lines do not trace the same part, and the routine returns to step S11. . Here, a message indicating that it is not an erase gesture may be displayed on the display device 11. In this case, the control unit 19 does not perform the erasing process in response to the erasing gesture. Then, since the line is displayed in step S27 described above, an elliptical line is drawn.

  On the other hand, if it is determined in step S57 that the difference in size between the outermost region and the innermost region is within the threshold, the control unit 19 extracts the region surrounded by the drawn line (step S59). The line already drawn in the extracted area is deleted (step S61).

≪Determination of lines to be erased≫
Here, some aspects will be described in which the control unit 19 determines a line to be erased when it is determined that the handwritten locus is an erase gesture.
First, the case of the wrapping line-shaped erasing gesture will be described.
As described in step S49 of FIG. 7 described above, the control unit 19 extracts an area covered by the handwriting locus. In the first mode for determining this region, a portion where three lines divided by two turning points overlap is extracted as the region. That is, it is a mode in which the part traced three times is extracted.

In the second mode, an area in which any of the three lines is drawn is extracted as the area. That is, the part in which any line of the handwritten locus is drawn is extracted as the region.
The user may be allowed to select which mode is to be applied using a setting menu.

When the region covered by the handwriting locus is extracted in this way, the control unit 19 determines a line to be erased based on the relationship with the region as described in step S51. When the handwriting locus is drawn, the already drawn line is the object to be erased.
When the control unit 19 determines the erasure target, there are several modes. The first mode is a mode of erasing a pixel portion at a portion that intersects with the region extracted in the process of step S49.

  FIG. 9 is an explanatory diagram showing an example of a mode in which the control unit according to the present invention determines the erasure target. FIG. 9A shows a state in which an area (cover area) covered by the handwritten locus is extracted from a line-shaped erasing gesture drawn on the already drawn characters “to”. The cover area 37 is an area shown in gray. FIG. 9B shows an erasure target determined by the control unit 19 in the case of the first aspect described above. Of the lines constituting the characters “to”, only the pixels that intersect the cover area 37 are to be erased.

The second mode is a mode in which all lines connected to the portion intersecting with the cover region 37 are erased. According to this aspect, the entire character “TO” that intersects the cover area 37 in FIG. 9A is to be erased.
However, according to this aspect, when one character is composed of a plurality of isolated lines (connected components), a part of the character is deleted.

  FIG. 10 is an explanatory diagram showing an example in which the control unit according to the present invention determines an erasure target. FIG. 10A shows a case where the cover area 37 is positioned on the character “ha” already drawn. FIG. 10B shows the first aspect described above, and only the pixels that intersect with the cover region 37 among the lines constituting the character “ha” are to be erased. FIG. 10C shows a second mode, in which the connected component on the right side that intersects the cover area 37 among the lines constituting the character “ha” is to be erased, but the connected component on the left side is erased. It remains without being targeted.

The third mode is a mode in which the erasure target is determined in units of objects. For example, if the character “ha” in FIG. 10 is one object, the entire character “ha” of the object that intersects the cover area 37 is to be erased. The object here refers to a unit selected using the “select” button on the toolbar 33. That is, when a handwriting locus is drawn in the work area 35, the unit that the control unit 19 processes as a series of handwriting locus is an object. For example, a series of handwritten trajectories drawn after a “pen” button on the toolbar 33 is touched until another button is touched is one object.
The user may be allowed to select which of the first to third modes is applied using a setting menu.

Next, the case of an elliptical erase gesture will be described.
The control unit 19 extracts a region surrounded by an ellipse in step S59 of FIG. 8 described above. At this time, even if the start point and the end point of the handwriting locus are slightly apart and a complete closed region is not formed, the closed region is determined by complementing with a straight line or a curve connecting them. Moreover, what is necessary is just to let the closed area | region comprised by the outermost area | region of an ellipse be the boundary of the said area | region. As a different mode, a closed region constituted by the innermost region may be used as the boundary of the region. It may be possible for the user to select which one to apply by using a setting menu.

  After extracting the region surrounded by the handwritten locus in this way, the control unit 19 determines a line to be erased based on the relationship with the region as described in step S61. As for this processing, similar to step S51 in the folding line, (1) a mode in which only the pixels that intersect with the extracted region are erased, and (2) a mode in which all lines connected to the portion that intersects with the region are erased. (3) A mode of determining the erasure target in units of objects is applicable. It may be possible for the user to select which one to apply by using a setting menu.

≪Modification≫
Some modifications of the embodiments described so far are listed.
First, the turning point of the erase gesture is not limited to two, and may be a different natural number such as three or four. The number of turning points may be set by the user.
In addition, when the lines intersecting with the handwriting locus determined to be the erasing gesture are all drawn before the predetermined time from the time when the handwriting locus is drawn, the control unit 19 erases the handwriting locus. It may be determined that it is not, and it may be handled as normal writing. This is because immediately after drawing a line, it is determined that it is not an action traced on the line in an attempt to erase it.

In addition, although a folded line-shaped erase gesture and an elliptical erase gesture have been mentioned, an X-shaped (X or X) -shaped gesture is conceivable as a different gesture. Then, an undo process may be associated with the X-shaped gesture instead of the erase gesture. The undo function is a function that undoes the processing performed before the gesture is drawn.
In addition to the embodiments described above, there can be various modifications of the present invention. These modifications should not be construed as not belonging to the scope of the present invention. The present invention should include the meaning equivalent to the scope of the claims and all modifications within the scope.

11: Display device 13: Liquid crystal display 15: Touch panel 17: Stand 19: Control unit 21: Storage unit 19a: Display control unit 19b: Input detection unit 21a: Input coordinate storage unit 21b: Graphic drawing information storage unit 21c: Time storage unit 31: Finger 33: Toolbar 35: Work area 37: Cover area

Claims (5)

A display unit capable of displaying handwritten characters and handwritten line drawings;
When the position touched by the display unit moves with time, a detection unit that detects the position as a handwritten locus;
When the detection unit and the display unit are controlled to display a line corresponding to the handwriting locus on the display unit and it is determined that a predetermined pattern as a gesture matches the handwriting locus, the line is associated with the gesture. And a control unit for executing the processing,
The gesture includes an erase gesture for erasing a line already displayed on the display unit,
When the handwriting trajectory is newly detected, the control unit determines the handwriting trajectory as an erasure gesture only when the period from when the handwriting trajectory is started to when the handwriting trajectory is finished is within a predetermined time. If the pattern is not drawn within the predetermined time, it is not an erase gesture, and the pattern has a predetermined number or more of bent lines, elliptical lines, and intersections. Determine whether it matches any of the straight lines,
When it is determined that the handwriting locus matches the pattern of the erasing gesture, the line overlapping the handwriting locus is erased. When the handwriting locus is determined to be a different pattern from the erasing gesture, the line overlapping the handwriting locus is A display device with a handwriting input function, characterized by being displayed. The detection unit detects a handwritten locus having a thickness,
2. The display device according to claim 1 , wherein the control unit erases a portion that overlaps the handwriting locus having the thickness among lines determined to overlap the handwriting locus and does not erase a portion that does not overlap. Wherein the control unit, the display device according to claim 1 or 2 erases the entire line joining the portions determined to overlap the handwritten locus. The detection unit detects a handwritten locus having a thickness,
The control unit determines that the portion of the line that is determined to overlap the handwriting locus does not delete the portion that overlaps the handwriting locus having the thickness and does not delete, or is overlapped with the handwriting locus. The display device according to claim 1, wherein selection of a mode for erasing the entire line connected to the selected portion is accepted, and the line is erased in the selected mode. The control unit determines whether the handwriting trajectory coincides with the erasure gesture only when the time from when the handwriting trajectory starts to be drawn to when the handwriting trajectory is finished is shorter than a predetermined period. display device according to any one of claims 1-4 long time to display a line at a position corresponding to the handwriting trajectory.