KR20120072503A - Method for removing line cross phenomenon of touch screen display device - Google Patents

Abstract

PURPOSE: A line cross removing method of an infrared ray touch screen display device is provided to prevent intersection of two straight lines by switching a tracking ID of two touch points. CONSTITUTION: A tracking ID of two touch points is confirmed in a previous frame period(S1). The tracking ID of two touch points is confirmed by being recognized as touch in current frame section(S2). The touch points of the tracking ID are connected(S3). If two lines are crossed, a tracking ID of the two touch points is switched(S5). If two lines are not crossed, the tracking ID is maintained(S6).

Description

Line cross removal method of infrared touch screen display device {METHOD FOR REMOVING LINE CROSS PHENOMENON OF TOUCH SCREEN DISPLAY DEVICE}

The present invention relates to an infrared touch screen display device, and more particularly, to a method for removing line crosses of an infrared touch screen display device capable of removing line crosses.

In general, a touch screen display device is one of various methods for configuring an interface between a user and an information communication device using various displays, and an input device that allows a user to interface with the device by directly touching the screen with a hand or a pen. to be.

The touch screen display device is an input device that can be easily used by both men and women by interactively and intuitively by simply touching a button displayed on the display unit with a finger. Therefore, a device for issuing banks and government offices, various medical equipment, tourism And it is applied in many fields such as guidance of major organizations, traffic guidance.

The touch screen display device may include a resistive type, a capacitive type, an ultrasonic wave type, an infrared type, or the like according to a method of recognizing.

Although the advantages of the above-described methods are different from each other, in recent years, an infrared touch screen display apparatus has been focused for minimizing pressure applied to the touch surface and for ease of arrangement.

However, the conventional infrared touch screen display device has a problem of incorrectly recognizing the coordinates of the virtual image as the actual coordinates because it cannot accurately distinguish between the real image and the virtual image when determining coordinates of a plurality of touch points. As a result, when drawing two straight lines simultaneously, a line cross phenomenon in which the two straight lines cross each other may appear.

FIG. 1 is a diagram illustrating a line cross phenomenon occurring in a conventional infrared touch screen display, and FIG. 2 is an enlarged view of part A of FIG. 1.

As shown in FIG. 1 and FIG. 2, it can be seen that, unlike the user's intention to draw two non-intersecting straight lines, the two straight lines L1 and L2 cross each other on the display unit.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object thereof is to provide a method for removing a line cross of an infrared touch screen display device capable of eliminating a line cross phenomenon.

According to an aspect of the present invention, there is provided a method for removing a line cross of an infrared touch screen display device, the method including: checking a tracking ID of each of two touch points recognized as touches in a previous frame period; Checking a tracking ID of each of the two touch points recognized as touches in the current frame period; Step C of connecting touch points of the same tracking ID generated in different frame periods in a straight line; Determining whether two straight lines cross each other; And when the two straight lines cross each other, the tracking IDs of the two touch points recognized as touches in the current frame period are exchanged with each other. If the two straight lines do not intersect, the tracking IDs of the two touch points recognized as touches in the current frame period are changed. Characterized in that the step E to maintain the tracking ID as it is.

The two touch points of the previous frame period are divided into a first touch point assigned with tracking ID 1 and a second touch point assigned with tracking ID 2; The two touch points of the current frame period are divided into a third touch point assigned with tracking ID 1 and a fourth touch point assigned with tracking ID 2.

The step D may include generating a first straight line connecting the first touch point and the third 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 with respect to the first straight line; Calculating a second value by substituting the x-axis coordinate value and the y-axis coordinate value of the fourth touch point into the first linear equation; Generating a second straight line connecting the second touch point and the fourth 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 with respect to the second straight line; Calculating a fourth value by substituting the x-axis coordinate value and the y-axis coordinate value of the third touch point into the second linear equation; And determining that the first and second straight lines cross each other when the first product is multiplied by the second value is less than 0, and the third product is multiplied by the fourth value is less than zero. And determining that the first straight line and the second straight line do not intersect when the above-described condition is not satisfied.

In step E, when the first straight line and the second straight line cross each other, the tracking ID of the third touch point is changed to No. 2 and the tracking ID of the fourth touch point is changed to No. 1, and If the second straight line does not intersect, 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.

The previous frame period is an nth (n is a natural number) frame period, and the current frame is an n + mth (m is a natural number) frame period.

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

According to the present invention, when the two straight lines intersect, the tracking IDs of the two touch points recognized as touches in the current frame period are swapped with each other to prevent the two straight lines from crossing each other. Therefore, the line cross phenomenon can be eliminated.

1 is a diagram illustrating a line cross phenomenon occurring in a conventional infrared touch screen display device.
2 is an enlarged view of a portion A of FIG. 1;
3 illustrates a touch screen display device according to an exemplary embodiment of the present invention.
4 is a flowchart illustrating a method of removing a line cross according to an exemplary embodiment of the present invention.
FIG. 5 is a flow chart showing the subdivision of step S4 of FIG.
FIG. 6 is a view for explaining a method of determining whether two straight lines intersect each other using the cross condition equation 1 and the cross condition equation 2. FIG.
7 is a view showing the form before and after the line cross removal;

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

As shown in FIG. 1, the touch screen display device according to an exemplary embodiment of the present invention includes a touch screen panel TP, first to third infrared cameras CAM1 to CAM3, and a retroreflective plate SR.

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

The retroreflective plate SR is positioned on four sides of the touch screen panel TP. The retroreflective plate SR is composed of a retro-reflecting layer formed by stacking a plurality of prisms.

Each of the infrared cameras CAM1 to CAM3 includes an infrared light emitting diode (LED) for emitting infrared light, an objective lens for collecting incident light, a photo sensor for sensing light collected by the objective lens, and an objective It includes an optical filter located on the front or rear of the lens. The incident light is incident on the photo sensor through the optical filter and the objective lens. In addition, the infrared LED serves to emit light toward the retroreflective plate SR. The resolution of the photo sensor may have a resolution of at least 500 pixels in the horizontal direction (to detect a position on at least 500 pixels in the horizontal direction).

Each of the infrared cameras CAM1 to CAM3 is provided with light that is retroreflected from at least two planes, and also detects infrared light emitted from the infrared camera at the other corner facing the corner where it is located. do.

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

The infrared cameras CAM1 to CAM3 are connected to the controller, and the controller calculates coordinates for the touch position by analyzing an optical signal for light detected by the infrared cameras CAM1 to CAM3.

The controller 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 the optical signal provided from the second infrared camera CAM2 and the third infrared camera ( The optical signal provided from CAM3 is analyzed by triangulation to calculate the number of touch points, each coordinate of the touch points, and a tracking ID for each of the touch points.

The number of touch points refers to 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 of the touch points. The tracking ID indicates which of the plurality of touch points has been touched first in time. In other words, when two points are touched at the same time, they are not touched at exactly the same point in time, but are touched with a subtle time difference. For example, when the touch point TP1 on the left side of FIG. 3 occurs earlier in time than the touch point TP2 on the right side, the controller gives tracking ID 1 to the touch point TP1 on the left side and the right side. Give tracking ID 2 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 plate, 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 controller assigns the same tracking ID to the touch point touched first and the plurality of touch points connected to the line in time, and then applies the same tracking ID to the touch point touched and the touch points connected to the line. This gives two straight lines.

However, as described above, when the distinction between the virtual image and the real image becomes ambiguous due to the limitation of the algorithm of the controller that determines the coordinates of the touch points, the virtual image coordinates may be misrecognized as the actual coordinates. In this case, a problem arises where two straight lines intersect. That is, the user intends to have two straight lines, but due to the misperception of the controller, the two straight lines appear to cross each other.

In the present invention, the line cross phenomenon in which two straight lines intersect is removed by using the following algorithm.

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

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

Subsequently, as shown in step S2, the tracking ID of each of the two touch points recognized as touches in the current frame period is checked.

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

Then, as shown in step S4, it is determined whether two straight lines cross. That is, it is determined whether two straight lines connecting touch points having the same tracking ID intersect each other.

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

Meanwhile, as shown in step S6, if two straight lines do not intersect, the tracking IDs of the two touch points recognized as touches in the current frame period are maintained as they are.

Then, as shown in step S7, the number of touch points of the current frame period, the tracking ID of each of these touch points, and the coordinates of each of the touch points identified through the step S5 or S6 to the operating system send. That is, the controller finally calculates the above-mentioned information about the touch points in the current frame period, and transmits the calculated information to the operating system.

Here, in determining whether the two straight lines cross at step S4, two cross condition equations may be used.

FIG. 5 is a flow chart showing the subdivision of step S4 of FIG. 4.

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 based on the cross condition equation (1).

In step S4-2, it is determined whether two lines intersect finally based on the cross-conditioning equation 2.

When the conditions according to the cross condition equation 1 and the cross condition equation 2 are satisfied, the controller determines that the two straight lines intersect.

On the other hand, when any one of the conditions according to the cross condition equation 1 and the cross condition equation 2 is not satisfied, the controller determines that the two straight lines do not intersect.

A method of determining whether two straight lines intersect using the cross condition equation 1 and the cross condition vertical 2 will be described in detail with reference to the following.

FIG. 6 is a diagram for describing a method of determining whether two straight lines intersect each other using the cross condition equation 1 and the cross condition equation 2. FIG.

As shown in FIG. 6, two touch points of the previous frame period (n-1) th Frame are the first touch point P1 and tracking ID number 2 (TID2) to which tracking ID 1 (TID1) has been assigned. ) Is divided into a second touch point P2.

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

First, as shown in (a) of FIG. 6, a first straight line f1 (x, y) connecting the first touch point P1 and the third touch point P3 to each other is generated.

Subsequently, the x-axis coordinate value and the y-axis coordinate value of the second touch point P2 are input to the first linear equation (a1 * x + b1 * y + c1) of the first straight line f1 (x, y). Substitution is performed to calculate 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 fourth touch point P4 into this first linear equation.

Subsequently, when the value obtained by multiplying the first value and the second value (Crossing Equation 1) is less than 0, it is determined that these two straight lines cross each other, and the following condition is further examined.

That is, as shown in (b) of FIG. 6, a second straight line f2 (x, y) connecting the second touch point P2 and the fourth touch point P4 to each other is generated.

Then, the x-axis coordinate value and the y-axis coordinate value of the first touch point P1 in the second linear equation (a2 * x + b2 * y + c2) for the second straight line f2 (x, y). Is substituted to calculate the third value. 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 third touch point P3 into the second linear equation.

Subsequently, when the value obtained by multiplying the third value and the fourth value (intersection conditional expression 2) is less than zero, it is finally determined that these two straight lines cross each other.

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

7 (a) shows a state in which the line cross elimination algorithm according to the present invention is not applied, and it can be seen that 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.

That is, according to the present invention, when the first straight line f1 (x, y) and the second straight line f2 (x, y) cross each other, the controller determines a tracking ID of the third touch point P3 by 1. By changing the number TID1 to the number 2 (TID2) and changing the tracking ID of the fourth touch point P4 from the number 2 (TID2) to the number 1 (TID1), as shown in FIG. We can ensure that the two straight lines do not intersect each other.

On the other hand, the previous frame period ((n-1) th Frame) is the nth (n is a natural number) frame period, and the current frame (n-th Frame) is the n + mth (m is a natural number) frame period. For example, the previous frame period may be a first frame period, and the current frame period may be a second frame period, which is a period immediately following 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: step

Claims (5)

Checking a tracking ID of each of the two touch points recognized as touches in the previous frame period;
Checking a tracking ID of each of the two touch points recognized as touches in the current frame period;
Step C of connecting touch points of the same tracking ID generated in different frame periods in a straight line;
Determining whether two straight lines cross each other; And,
If the two straight lines intersect, the tracking IDs of the two touch points recognized as touches in the current frame period are exchanged with each other. If the two straight lines do not intersect, the tracking IDs of the two touch points recognized as touches in the current frame period are interchanged. Method of removing the line cross of the infrared touch screen display device comprising the step of maintaining the same. The method of claim 1,
The two touch points of the previous frame period are divided into a first touch point assigned with tracking ID 1 and a second touch point assigned with tracking ID 2; And,
The two touch points of the current frame period are divided into a third touch point granted with tracking ID 1 and a fourth touch point assigned with tracking ID 2, and the method of removing the line cross of the infrared touch screen display device. . The method of claim 2,
The step D,
Generating a first straight line connecting the first touch point and the third 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 with respect to the first straight line;
Calculating a second value by substituting the x-axis coordinate value and the y-axis coordinate value of the fourth touch point into the first linear equation;
Generating a second straight line connecting the second touch point and the fourth 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 with respect to the second straight line;
Calculating a fourth value by substituting the x-axis coordinate value and the y-axis coordinate value of the third touch point into the second linear equation; And,
The first straight line and the second straight line are determined to intersect with each other when the first product is multiplied by the second value is less than zero, and the third product is multiplied by the fourth value is less than zero. And determining that the first and second straight lines do not intersect when the above condition is not satisfied. The method of claim 3, wherein
The step E,
When the first straight line and the second straight line cross each other, the tracking ID of the third touch point is changed to No. 2 and the tracking ID of the fourth touch point is changed to No. 1, and the first and second straight lines intersect. Otherwise, the tracking ID of the third touch point is maintained at number 1 and the tracking ID of the fourth touch point is maintained at number 2. The method of claim 1,
And the previous frame period is an nth (n is a natural number) frame period, and the current frame is an n + mth (m is a natural number) frame period.

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