KR101715856B1 - Method for removing line cross phenomenon of touch screen display device - Google Patents

Abstract

The present invention relates to a line cross removal method for an infrared touch screen display capable of eliminating a line cross phenomenon, comprising the steps of: A) identifying a tracking ID of each of two touch points recognized by a touch in a previous frame period; A step B for confirming a tracking ID of each of two touch points recognized by a touch in the current frame period; A step C of linearly connecting the touch points of the same tracking ID generated in different frame periods; Determining whether two straight lines intersect; When the two straight lines intersect, the tracking IDs of the two touch points recognized by the touch in the current frame period are matched with each other. If two straight lines do not intersect with each other, the two touch points And an E step of keeping the tracking ID as it is.

Description

METHOD FOR REMOVING LINE CROSS PHENOMENON OF TOUCH SCREEN DISPLAY DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared touch screen display device, and more particularly, to a line cross removal method of an infrared touch screen display device capable of eliminating a line cross.

2. Description of the Related Art Generally, a touch screen display device is one of various methods of configuring an interface between an information communication device and a user using various displays, and is an input device capable of interfacing with a device by directly touching the screen with a hand or a pen to be.

Since the touch screen display device is an input device that can be easily used by both men and women by interactively and intuitively operating the buttons displayed on the display unit only by touching them with fingers, And guidance of major institutions, traffic information, and so on.

Such a touch screen display device may be classified into a resistive type, a capacitive type, an ultrasonic wave type, and an infrared type according to a method of recognizing the touch screen.

Although the advantages of each of the above-described methods are different from each other, in recent years, an infrared type touch screen display device has been attracting attention due to minimization of pressure applied to the touch surface and convenience of disposition.

However, the conventional infrared touch screen display device has a problem that the coordinates of the virtual image are mistakenly recognized as the real coordinates because the real image and the virtual image can not be distinguished accurately when determining coordinates for a plurality of touch points. As a result, when two straight lines are simultaneously drawn, a line cross phenomenon in which the two straight lines cross each other may appear.

FIG. 1 is a view showing a line cross phenomenon generated in a conventional infrared touch screen display device, and FIG. 2 is an enlarged view of part A of FIG.

As shown in FIGS. 1 and 2, it can be seen that, unlike the intention of the user who wants to draw two non-intersecting straight lines, the display shows two straight lines L1 and L2 crossing each other.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a line cross removal method of an infrared touch screen display device capable of eliminating a line cross phenomenon.

According to another aspect of the present invention, there is provided a method of removing a line cross of an infrared touch screen display device, comprising the steps of: A) identifying a tracking ID of each of two touch points recognized in a previous frame period; A step B for confirming a tracking ID of each of two touch points recognized by a touch in the current frame period; A step C of linearly connecting the touch points of the opposite tracking ID generated in different frame periods; Determining whether two straight lines intersect; When the two straight lines intersect, the tracking IDs of the two touch points recognized by the touch in the current frame period are matched with each other. If two straight lines do not intersect with each other, the two touch points And an E step of keeping the tracking ID as it is.

The two touch points in the previous frame period are divided into a first touch point given a tracking ID number 1 and a second touch point given a tracking ID number 2; In addition, the two touch points in the current frame period are divided into a third touch point given a tracking ID number 1 and a fourth touch point given a tracking ID number 2.

The step (D) includes: generating a first straight line connecting the first touch point and the fourth touch point to each other; Calculating a first value by substituting an x-axis coordinate value and a y-axis coordinate value of the second touch point into a first linear equation for the first straight line; Calculating a second value by substituting the x-axis coordinate value and the y-axis coordinate value of the third touch point into the first linear equation; Generating a second straight line connecting the second touch point and the third touch point to each other; Calculating a third value by substituting an x-axis coordinate value and a y-axis coordinate value of the first touch point into a second linear equation for the second straight line; Calculating a fourth value by substituting an x-axis coordinate value and a y-axis coordinate value of the fourth touch point into the second linear equation; And judging that the first straight line and the second straight line cross each other when the value obtained by multiplying the first value by the second value is smaller than 0 and the value obtained by multiplying the third value by the fourth value is smaller than 0 And determining that the first straight line and the second straight line do not intersect when the above-described condition is not satisfied.

In the step E, when the first straight line intersects with the second straight line, the tracking ID of the third touch point is changed to 2, the tracking ID of the fourth touch point is changed to 1, The tracking ID of the third touch point is maintained at 1 and the tracking ID of the fourth touch point is maintained at 2 when the second straight line does not intersect.

Wherein the previous frame period is an n-th (n is a natural number) frame period, and the current frame is an (n + m) th (m is a natural number) frame period.

The line cross removal method of the infrared touch screen display device according to the present invention has the following effects.

According to the present invention, when two straight lines intersect, the two straight lines can be prevented from intersecting by aligning the tracking IDs of the two touch points recognized by touch in the current frame period. Therefore, the line cross phenomenon can be eliminated.

1 is a diagram showing a line cross phenomenon generated in a conventional infrared touch screen display device
Fig. 2 is an enlarged view of part A of Fig. 1
3 is a diagram illustrating a touch screen display device according to an embodiment of the present invention.
4 is a flowchart showing a line cross removal method according to an embodiment of the present invention.
5 is a flowchart showing the subdivision of step S4 in Fig.
FIG. 6 is a diagram for explaining a method for determining whether or not two straight lines intersect using the intersecting condition equation 1 and the intersecting condition equation 2
Fig. 7 is a view showing the shape before line cross removal and after line cross removal

3 is a diagram illustrating a touch screen display apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the touch screen display apparatus according to an embodiment of the present invention includes a touch screen panel TP, first through third infrared cameras CAM1 through CAM3, and a recursive reflector SR.

The first to third infrared cameras are located at three corners of the touch screen panel TP.

The retroreflector (SR) is located on four sides of the touch screen panel (TP). This retroreflective sheet SR is constituted by a retro-reflecting layer formed by stacking a plurality of prisms.

Each of the infrared cameras CAM1 to CAM3 includes an infrared LED (light emitting diode) for emitting infrared light, an objective lens for condensing the incident light, a photosensor for sensing light condensed by the objective lens, And an optical filter located on the front or back of the lens. The incident light is incident on the photo sensor through the optical filter and the objective lens. The infrared LED plays a role of emitting light toward the retroreflective plate (SR). The resolution of the photosensor may have a resolution of 500 pixels or more in the horizontal direction (so as to detect the position on 500 or more pixels in the horizontal direction).

Each of the infrared cameras CAM1 to CAM3 receives the light reflected from at least two surfaces and detects the infrared light emitted from the infrared camera at the other corner facing the corner where the camera is located. do.

In addition, when there is a touch on the display portion DP of the touch screen panel TP, the light reflected from the recursive reflection plate SR or the light at the touch point of the contacted object (input means such as a hand or a pen) is blocked , Each infrared camera detects the point at which this light is blocked.

The infrared cameras CAM1 to CAM3 are connected to a control unit which analyzes the optical signals for the light detected from the infrared cameras CAM1 to CAM3 and calculates coordinates for the touch position.

The control unit analyzes the optical signal provided from the first infrared camera (CAM1) and the optical signal provided from the second infrared camera (CAM2) by triangulation and transmits the optical signal provided from the second infrared camera (CAM2) CAM3) is analyzed by the triangulation method to calculate the number of touch points, each coordinate of touch points, and a tracking ID for each touch point.

The number of touch points means the number of touch points touched on the display unit DP of the touch screen panel TP. Each coordinate of the touch points means an x-axis coordinate value and a y-axis coordinate value of each touch point. The tracking ID indicates which one of a plurality of touch points is first touched in time. That is, when two points are touched simultaneously, these two points are not actually touched at exactly the same time, and are touched with a subtle time difference. For example, if the left touch point TP1 in FIG. 3 is generated temporally earlier than the right touch point TP2, the control unit assigns the tracking ID 1 to the left touch point TP1, A tracking ID 2 is assigned to the touch point TP2.

When the user moves downward while touching two fingers on the display unit DP to draw two lines on the paint board, a plurality of discontinuous touch points are sequentially generated on the display unit DP, These touch points are recognized as one continuous line. That is, the control unit assigns the same tracking ID to touch points that are touched first in time and a plurality of touch points that are connected to the touch points in time, So that two straight lines are generated.

However, as described above, when the distinction between the virtual image and the real image becomes ambiguous owing to the limitation of the algorithm of the control unit for determining the coordinates of the touch points, the coordinates of the virtual image may be misinterpreted as the actual coordinates. In such a case, there is a problem that two straight lines intersect. That is, the user intends two straight lines, but the two straight lines intersect each other due to the erroneous recognition of the control unit.

In the present invention, the following cross-line crossing phenomenon is eliminated by using the following algorithm.

4 is a flowchart illustrating a line cross removal method according to an embodiment of the present invention.

First, as shown in step S1, a tracking ID of each of two touch points recognized by a touch in the previous frame period is checked.

Then, as shown in step S2, the tracking ID of each of the two touch points recognized by the touch in the current frame period is confirmed.

Next, as shown in step S3, touch points of the same tracking ID generated in different frame periods are connected by a straight line. That is, any one of the touch points of the previous frame period and the touch point of the current frame period is connected by a straight line. At this time, the two touch points should have the same tracking ID. Similarly, another touch point of the previous frame period and another touch point of the current frame period are connected in a straight line. These two touch points must also have the same tracking ID.

Then, as shown in step S4, it is determined whether or not two straight lines intersect with each other. That is, it is determined whether the two straight lines connecting the touch points having the same tracking ID cross each other.

Then, as shown in step S5, when the two straight lines intersect, the tracking IDs of the two touch points recognized by the touch in the current frame period are swapped with each other. That is, the tracking ID of one touch point in the current frame period is matched with the tracking ID of another touch point in the current frame period. Accordingly, the tracking ID of one touch point in the current frame period is converted into the tracking ID of another touch point, and the tracking ID of another touch point is converted into the tracking ID of one touch point.

On the other hand, if the two straight lines do not intersect, as shown in step S6, the tracking IDs of the two touch points recognized as touched in the current frame period are maintained.

Thereafter, as shown in step S7, the number of touch points of the current frame period, the tracking ID of each of the touch points, and the coordinates of each of the touch points detected through S5 or S6 are transmitted to the operating system send. That is, the control unit finally calculates the above-described information about the touch points in the current frame period, and transmits the calculated information to the operating system.

Here, in the step S4, two intersecting conditional equations can be used in determining the intersection of two straight lines.

5 is a flowchart showing the subdivision of step S4 of FIG.

As shown in FIG. 5, step S4 includes steps S4-1 and S4-2.

In step S4-1, it is determined whether two straight lines intersect first based on the intersection condition equation 1. [

In step S4-2, it is determined whether or not the two straight lines intersect based on the intersecting condition equation (2).

When both the conditions according to the intersecting condition equation 1 and the intersecting condition equation 2 are satisfied, the control section judges that the two straight lines intersect.

On the other hand, when none of the conditions according to the intersecting condition equation 1 and the intersecting condition equation 2 is satisfied, the controller determines that the two straight lines do not intersect with each other.

A method of determining the intersection of two straight lines using the intersecting condition 1 and the intersecting condition vertical 2 will be described in detail as follows.

FIG. 6 is a diagram for explaining a method for determining whether two straight lines intersect using the intersecting condition equation 1 and the intersecting condition equation 2. FIG.

6, the two touch points in the previous frame period ((n-1) th Frame) are the first touch point P1 and the second tracking ID TID2, And a second touch point P2 to which the second touch point P2 is assigned.

Similarly, the two touch points in the current frame period (n-th Frame) are the third touch point P3 given the tracking ID 1 (TID1) and the fourth touch point P3 given the tracking ID 2 (TID2) P4).

First, as shown in Fig. 6 (a), a first straight line f1 (x, y) connecting the first touch point P1 and the fourth touch point P4 is generated.

Thereafter, the x-axis coordinate value and the y-axis coordinate value of the second touch point P2 are set to the first linear equation (a1 * x + b1 * y + c1) for the first straight line f1 And calculates the first value. Here, a1, b1 and c1 are all constants.

Subsequently, the second value is calculated by substituting the x-axis coordinate value and the y-axis coordinate value of the third touch point P3 into the first linear equation.

Then, when the value obtained by multiplying the first value by the second value (intersection condition equation 1) is smaller than 0, it is judged that these two straight lines intersect first, and the following condition is further examined.

That is, as shown in FIG. 6 (b), a second straight line f2 (x, y) connecting the second touch point P2 and the third touch point P3 is generated.

Thereafter, the x-axis coordinate value and the y-axis coordinate value of the first touch point P1 are added to the second linear equation (a2 * x + b2 * y + c2) for the second straight line f2 And the third value is calculated. Here, a2, b2, and c2 are all constants.

Next, the fourth value is calculated by substituting the x-axis coordinate value and the y-axis coordinate value of the fourth touch point P4 into this second linear equation.

Thereafter, when the value obtained by multiplying the third value by the fourth value (the intersection condition equation 2) is smaller than 0, it is finally determined that the two straight lines intersect.

Fig. 7 is a view showing a form before line cross removal and after line cross removal.

FIG. 7A shows a state in which the line cross elimination algorithm according to the present invention is not applied, and it can be seen that the two straight lines cross each other.

However, when the line cross elimination algorithm according to the present invention is applied, it can be seen that the two straight lines are corrected so as not to intersect as shown in FIG. 7 (b).

That is, according to the present invention, when the first straight line f1 (x, y) intersects with the second straight line f2 (x, y), the control unit sets the tracking ID of the third touch point P3 to 1 And the tracking ID of the fourth touch point P4 is changed from No. 2 (TID2) to No. 1 (TID1), as shown in FIG. 7 (b) , So that the two straight lines do not intersect with each other.

The previous frame period (n-1) th frame described above is the n-th (n is a natural number) frame period, and the current frame (n-th Frame) is the (n + m) th (m is a natural number) frame period. For example, the previous frame period may be the first frame period, and the current frame period may be the second frame period immediately after the first frame period.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. Will be clear to those who have knowledge of.

S1 to S7:

Claims (5)

An A step of identifying a tracking ID of each of two touch points recognized by a touch in a previous frame period;
A step B for confirming a tracking ID of each of two touch points recognized by a touch in the current frame period;
A step C of linearly connecting the touch points of the opposite tracking ID generated in different frame periods;
Determining whether two straight lines intersect; And
If the two straight lines intersect, the tracking IDs of the two touch points recognized by the touch in the current frame period are matched with each other. If the two straight lines do not intersect with each other, Wherein the step (c) includes the step (e). The method according to claim 1,
The two touch points in the previous frame period are divided into a first touch point given a tracking ID number 1 and a second touch point given a tracking ID number 2; And,
Wherein the two touch points of the current frame period are divided into a third touch point given a tracking ID number 1 and a fourth touch point given a tracking ID number 2, . 3. The method of claim 2,
The step (D)
Generating a first straight line connecting the first touch point and the fourth touch point to each other;
Calculating a first value by substituting an x-axis coordinate value and a y-axis coordinate value of the second touch point into a first linear equation for the first straight line;
Calculating a second value by substituting the x-axis coordinate value and the y-axis coordinate value of the third touch point into the first linear equation;
Generating a second straight line connecting the second touch point and the third touch point to each other;
Calculating a third value by substituting an x-axis coordinate value and a y-axis coordinate value of the first touch point into a second linear equation for the second straight line;
Calculating a fourth value by substituting an x-axis coordinate value and a y-axis coordinate value of the fourth touch point into the second linear equation; And
When the value obtained by multiplying the first value by the second value is less than 0 and the value obtained by multiplying the third value by the fourth value is less than 0, it is determined that the first straight line intersects with the second straight line, And determining that the first straight line and the second straight line do not intersect with each other when the condition is not satisfied. The method of claim 3,
In the step E,
The tracking ID of the third touch point is changed to 2 and the tracking ID of the fourth touch point is changed to 1 when the first straight line and the second straight line intersect with each other and the first straight line and the second straight line cross each other The tracking ID of the third touch point is maintained at 1 and the tracking ID of the fourth touch point is maintained at the second touch point. The method according to claim 1,
Wherein the previous frame period is an n-th (n is a natural number) frame period, and the current frame is an (n + m) th (m is a natural number) frame period.

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