KR20110011337A - Multi-touch detection apparatus and method for projective capacitive touch screen - Google Patents

Abstract

PURPOSE: A multi-touch detecting apparatus on a projective capacitive touch screen and a method thereof are provided to remove ghost touch information from detected touch spot information. CONSTITUTION: Noise against obtained row electrode data and column electrode data is removed(S430). Offset data is removed from the row electrode data and column electrode data(S440). Touch point information of a user is detected about a touch screen from the row electrode data and column electrode data(S450). Information about an actually touched location is tracked among the detected touch spot information(S460).

Description

MULTI-TOUCH DETECTION APPARATUS AND METHOD FOR PROJECTIVE CAPACITIVE TOUCH SCREEN}

One embodiment of the present invention relates to an apparatus and a method capable of sensing a multi-touch position with respect to a projection capacitance touch screen.

The touch screen can be used intuitively and easily from a user's point of view, compared to a device using a button or keypad, and a device manufacturer can provide a colorful graphical user interface. In addition, the touch screen can eliminate mechanical buttons, enabling a beautiful design of the device, and utilizes the space occupied by the existing buttons as an additional display space, making it an interface suitable for full browsing requiring a large screen. . Due to these advantages, touch screens are being used in various fields such as mobile devices, industrial devices, game devices, etc. beyond the limited applications such as ATMs and kiosks of banks, and the market size is rapidly growing.

According to an embodiment of the present invention, a multi-touch sensing device groups each row electrode data and column electrode data of a touch screen to detect touch point information on the touch screen, and a user in the detected touch point information. It includes a touch point tracking unit for tracking the actual touch point actually touched by.

In addition, the multi-touch sensing method according to an embodiment of the present invention is to group each of the row electrode data and column electrode data of the touch screen to detect the touch point information on the touch screen and to the user from the detected touch point information Tracking the actual touch point that was actually touched by.

An apparatus and method for accurately detecting a multi-touch position in a projection capacitive touch screen according to an embodiment of the present invention can be provided.

Hereinafter, with reference to the accompanying drawings will be described an embodiment according to the present invention; However, the present invention is not limited or limited by the embodiments. Also, like reference numerals in the drawings denote like elements.

The technologies used in touch screens are the most popular types of portable devices such as resistive type and projection capacitance type. The resistance method is a method of inputting a pressure sensor installed on the surface of the touch screen each time it is pressed. Projection capacitance method is composed of two layer bases each having horizontal and vertical transparent electrode lines arranged to face each other so that when the conductor such as a finger is connected, it detects the change in capacitance occurring at the location and determines the location. This excellent and beautiful design has the advantage of being possible.

1 is a diagram illustrating a touch position detection principle of a projection capacitive touch screen using a line scanning method.

As shown in FIG. 1, a typical projection capacitance touch screen senses whether the horizontal and vertical electrodes are in contact with the user's finger through line scanning, and then detects the intersection of the two electrodes in contact with the touch position.

As shown in FIG. 1, when the finger touches the projection capacitive touch screen, the interpolation method may be applied to a value measured at the contact electrode and the electrode around the touch screen to improve the touch position detection resolution. The row electrodes C ₁ to C ₇ and the column electrodes R ₁ to R ₆ are arranged at positions P _c1 to P _c7 and P _r1 to P _{r6 on} the X-axis Y-axis, respectively, and x _c1 to x _c7 and x _r1 to x _r6 are measured values of the row electrode and the column electrode, respectively.

The most popular method for such interpolation is a weighted average method such as Equation (1).

Where N is the number of row electrodes and M is the number of column electrodes.

This interpolation method is suitable for the application of the touch screen which needs only to sense a single contact, but when applied to a multi-touch application, there is a problem in that the position of the multi-touch is not detected correctly.

2 is a diagram illustrating a problem of the projected capacitance touch screen during multi-touch.

Referring to FIG. 2, in the multi-touch projection capacitive touch screen, the position detection of the multi-touch becomes inaccurate due to the median problem (a) and the ghost touch problem (b).

The median problem (a) is that when applying the position detection algorithm to the output value of the touch screen sensor without any consideration, only one median value 202 of the multi-touch point is detected when two or more points 201 and 203 are touched. Is generated. In order to solve the median problem (a), one embodiment of the present invention may observe the electrode measurements and then divide the measurements for each row and column electrode into groups and apply Equation 1 to each.

The ghost touch problem (b) is a phenomenon in which unnecessary touches 211 and 213 irrespective of the actual touch positions 201 and 203 are detected and thus the exact number and location of the touches cannot be detected. Occurs in the back. In order to solve the ghost touch problem (b), an embodiment of the present invention applies a separate error correction algorithm when detecting a position to detect only a touch operation by a finger, thereby preventing an operation error of the touch screen, and grasping the detected multi-touch. By removing unnecessary data such as ghost touch among the positions, the actual touch position can be identified, and a unique ID can be assigned to each actual touch position.

3 is a diagram illustrating a configuration of a multi-touch sensing device of a touch screen according to an embodiment of the present invention.

Referring to FIG. 3, the multi-touch sensing device 300 of the touch screen according to an embodiment of the present invention may include a data acquirer 310, a noise remover 320, an offset remover 330, and a touch point detector ( 340 and a touch point tracker 350.

The data acquirer 310 acquires row electrode data and column electrode data according to a user's touch operation on the touch screen. That is, the data acquisition unit 310 obtains the row electrode data and the column electrode data by converting the row signal and the column signal detected by the sensor of the touch screen into digital data through an analog / digital converter.

The noise removing unit 320 removes noise of the obtained row electrode data and column electrode data. That is, the noise removing unit 320 removes unnecessary noise from the row electrode data and the column electrode data transmitted from the data obtaining unit 310. For example, the noise canceller 320 may have a low frequency band rejection function as a moving average filter, and may be suitably used in an embedded system because the calculation amount is small.

The offset remover 330 removes the offset data from the row electrode data and the column electrode data from which the noise is removed. That is, the offset remover 330 receives the row electrode data and the column electrode data from which the noise is removed from the noise remover 320, and removes the offset data from the row electrode data and the column electrode data from which the noise is removed. .

5 shows raw data with offset, offset data, and offset-free data.

Referring to FIG. 5, the offset remover 330 removes the offset data 520 from the original data 510 including the offset and outputs the data 530 from which the offset is removed.

For example, the offset removing unit 330 may set the data when there is no contact with the touch screen as offset data and then remove the set offset data from the row electrode data and the column electrode data from which the noise is removed.

The touch point detector 340 groups the row electrode data and the column electrode data of the touch screen to detect the user's touch point information on the touch screen. That is, the touch point detector 340 groups the row electrode data and the column electrode data of the touch screen according to a predetermined criterion and detects the touch point information of the user with respect to the grouped row electrode data and the column electrode data. For example, the touch point detector 340 may group the row electrode data and the column electrode data from which the noise and the offset are removed to detect location information of the user's touch point with respect to the touch screen.

The touch point detector 340 analyzes signals generated in the row and column electrodes of the touch screen, extracts signal regions by the multi-touch, groups the extracted signal regions, and analyzes the grouped signal regions. Detect location information on the touch point of the user. For example, the touch point detector 340 binarizes the row electrode data and the column electrode data of the touch screen according to a preset reference value, clusters the binarized data for each level, and applies a weighted average algorithm to each cluster. Location information regarding the touch point of the user may be detected.

The touch point tracking unit 350 tracks the actual touch point actually touched by the user in the detected touch point information. That is, the touch point tracking unit 350 tracks the actual touch point according to a result of comparing the detected touch point information with past touch position information, and assigns an ID to the tracked actual touch point.

For example, the touch point tracking unit 350 tracks the actual touch point information that is actually touched by using a multi-touch location tracking algorithm that compares the detected touch point information with past touch location information, and the tracked actual touch point information. You can assign a unique ID to. Also, the touch point tracker 350 may remove ghost touch information detected due to unnecessary contact not related to the actual touch point from the detected touch point information.

4 is a diagram illustrating an operation flow of a multi-touch sensing method of a touch screen according to an embodiment of the present invention.

3 and 4, in step S410, the multi-touch sensing device 300 initializes the system. For example, in operation S410, the multi-touch sensing device 300 may include a data acquirer 310, a noise remover 320, an offset remover 330, a touch point detector 340, and a touch point tracker 350. You can initialize the operation of.

In operation S420, the multi-touch sensing device 300 obtains row electrode data and column electrode data according to a user's touch operation on the touch screen. For example, in step S420, the multi-touch sensing device 300 converts the row electrode signal and the column electrode signal generated according to a user's touch operation on the touch screen through the data acquisition unit 310 to perform analog / digital conversion. Row data and column electrode data can be obtained.

In operation S430, the multi-touch sensing apparatus 300 removes noise on the obtained row electrode data and column electrode data. For example, in operation S430, the multi-touch sensing apparatus 300 may remove unnecessary noise included in the obtained row electrode data and column electrode data through the noise remover 320.

In operation S440, the multi-touch sensing apparatus 300 removes offset data from the row electrode data and the column electrode data from which the noise is removed. For example, in operation S440, the multi-touch sensing apparatus 300 may remove the offset data from the row electrode data and the column electrode data from which the noise is removed through the offset remover 330.

In operation S450, the multi-touch sensing device 300 detects user touch point information on the touch screen from the row electrode data and the column electrode data from which the noise and offset are removed. For example, in operation S450, the multi-touch sensing apparatus 300 binarizes the row electrode data and the column electrode data from which the noise and the offset are removed through the touch point detector 340 according to a preset reference value, and the binary data. After clustering by level, a weighted average algorithm may be applied to each cluster to detect location information of the touch point of the user.

6 is a flow chart of a touch area grasping algorithm for row or column electrode data according to an embodiment of the present invention.

7 is a diagram illustrating an example of detecting a position of a touch point by clustering row or column electrode data.

6 and 7, the touch point detector 340 analyzes electrode signals S1 from each row and column electrode of the touch screen (S610), and analyzes the analyzed electrode signals S1 as reference values. Binary by (T) (S620). The touch point detector 340 retrieves the clusters C1 and C2 from the binarized data by a labeling algorithm (S630) and analyzes the center positions P1 and P2 of the clusters (S640). .

For example, the touch point detector 340 analyzes twelve column electrode signals S1 as shown in FIG. 7, and binarizes the analyzed column electrode signals S1 based on a result of comparing the analyzed column electrode signals S1 with a reference value T. Apply the labeling algorithm to the binarized data to search the clusters C1 and C2, and apply the weighted average algorithm to the searched clusters C1 and C2 to analyze the center positions P1 and P2, respectively. The location of the point can be detected.

와

로 정의하고, 각각에 대한 기준치를

와

로 정의한다. 여기서 N은 열 전극의 수, M은 행 전극의 수이다. 이러한 경우 열 전극들에 대한 레이블링 알고리즘의 의사 코드 (pseudo code)는 표 1에 도시된 것과 같으며 행 전극들에 대해서도 동일한 알고리즘을 적용하는 것이 가능하다. First, measure the signals from the column and row electrodes

Wow

Is defined as

Wow

. Where N is the number of column electrodes and M is the number of row electrodes. In this case, the pseudo code of the labeling algorithm for the column electrodes is as shown in Table 1, and it is possible to apply the same algorithm to the row electrodes.

; class label
l = 1; label index
i = 1;

if

;

for i = 2:N
if

if

l = l + 1;
end

;
end
end

; class label
l = 1; label index
i = 1;

if

;

for i = 2: N
if

if

l = l + 1;
end

;
end
end

)를 얻을 수 있다.The touch point detector 340 may detect a center position of the touch point by applying a weighted average algorithm to clusters to which the labeling algorithm is applied. For example, when the number of touch regions identified for each row electrode and column electrode is k and l, respectively, the total number of touch points is k × l, and the touch point detector 340 applies Equation 2 to the clusters. Location information for the touch point (

) Can be obtained.

Here, R _ck and R _rl denote k and l th touch regions of the row and column electrodes, respectively.

In operation S460, the multi-touch sensing apparatus 300 tracks the position information actually touched among the detected touch point information. For example, in operation S460, the multi-touch sensing apparatus 300 may track the position information actually touched among the detected touch point information through the touch point tracking unit 350.

In operation S460, the multi-touch sensing device 300 tracks the actual touch point information that is actually touched by using a multi-touch location tracking algorithm that compares the detected touch point information with past touch location information, and the tracked actual Assign a unique ID for touch point information.

Since the touch screen detects a plurality of touch positions, the multi-touch sensing apparatus 300 may not reflect the user's actual touch operation. Therefore, the multi-touch sensing apparatus needs to track the position of the touch point according to the multi-touch position tracking algorithm. The multi-touch position tracking algorithm is a method of allocating an ID by comparing a distance between a touch position of a current time and a touch position of a previous time.

The multi-touch location tracking algorithm according to an embodiment of the present invention will be described taking the case of two trackable touch locations as an example. The number of possible touches at the previous sample instant is 0, 1, 2, and the possible number of touch positions obtained through the touch point detection algorithm at the current sample instant are 0, 1, 2, 4.

FIG. 8 is a diagram illustrating a touch point detection result that may be generated by a touch point detection algorithm when two fingers touch each other.

Referring to FIG. 8, a circle represents a user's actual touch, and a rectangle represents a position of a touch point obtained through a touch point detection algorithm. The number of detected touches is 2, and the result that can be generated by the touch point detection algorithm when two fingers are in contact is when two fingers are placed vertically (a), two fingers are placed horizontally (b) and two fingers (C) is arranged diagonally.

The relationship between the position of the previous sample and the touch point of the current sample is as shown in Table 2.

Case Number of Previous Pointers (NP) Number of Current Pointers including ghost pointers (NT) Note One 0 0 No tracking 2 0 One No tracking.
Assign default ID 3 0 2 No tracking
Random ID assignment 4 0 4 Unidentifiable
Return error 5 One 0 No tracking 6 One One No tracking
Assign previous ID 7 One 2 Pointer tracking 8 One 4 Pointer tracking
Ghost pointer elimination 9 2 0 No tracking 10 2 One Pointer tracking 11 2 2 Pointer tracking 12 2 4 Pointer tracking
Ghost pointer elimination

Referring to Table 1, case 1, 2, 3, 4, 5, 6, and 9 do not require location tracking for a separate touch point, and case 7, 8, 10, 11, and 12 may not be touched. Location tracking is required.

9 is a flowchart of a touch point tracking algorithm according to an embodiment of the present invention.

9, the touch point tracking unit 350 determines the number NP of previous touch points from the detected touch point information (S910).

The touch point tracker 350 detects the number NT of temporary touch points from the detected touch point information (S920). The number of temporary touch points includes the number of ghost touch points as well as the number of actual touch points.

If the current touch does not occur (NT = 0, S930) as shown in Case 1, 5, and 9 shown in Table 2, the touch point tracker 350 does not need to perform the touch point tracking algorithm and thus ends the operation. do.

If the touch point tracking unit 350 generates a single touch as shown in Case 2 shown in Table 2 ((NP, NT) = (0, 1), S940), the touch point tracking unit 350 provides a basic ID for the point where the single touch occurs. Assign (S945). In addition, the touch point tracking unit 350 allocates a random ID to each touch point when two touches occur at the same time as in Case 3 ((NP, NT) = (0, 2), S940) ( S945).

The touch point tracker 350 may touch the diagonal direction simultaneously without information about the previous touch point as in Case 4 shown in Table 2 ((NP, NT) = (0, 4), S950). In this case, since the touch point tracking algorithm cannot be processed (S955).

If the touch point tracking unit 350 performs a single touch movement as shown in Case 6 shown in Table 2 ((NP, NT) = (1, 1), S960), the touch of the current touch point is detected by the ID of the previous touch point. Assign to the point (S945).

The touch point tracking unit 350 detects a new touch while moving two touch positions as shown in Case 7, 10, and 11 shown in Table 2 ((NP, NT) = (1, 2), (2, 1) ), (2, 2), and S970), the touch point is tracked by applying a touch position tracking algorithm (S975), and an ID is assigned to the tracked touch point (S945). The touch location tracking algorithm is a method of allocating an ID by comparing a distance between a touch location of a current time and a touch location of a previous time. The touch position tracking algorithm assigns an appropriate ID for each touch point at the current sampling moment and associates it with the touch point at the previous sampling moment. For example, the touch point tracking unit 350 has information about the position and ID of the touch point at the previous sampling moment and the position of the temporary touch point at the current sampling moment, and according to the touch position tracking algorithm, ID can be assigned.

The touch point tracking unit 350 tracks the touch point when the ghost touch is generated ((NP, NT) = (1, 4), (2, 4)) as in Cases 8 and 12 (S985), The ghost touch is removed from the tracked touch point (S990). The ghost touch is a virtual touch in which no touch is actually generated among the tracked touch point information.

As such, the touch point tracking unit 350 may accurately track the actual touch location information by removing the ghost touch information detected due to unnecessary contact that is not related to the actual touch location information with respect to the detected multi-touch location information. Can be.

The touch point identified at the previous moment is PPi (i = 0, 1), and the touch point identified by the clustering algorithm is called TPj (j = 0, 1, 2, 4), and i and j are respectively It means ID.

Considering the case of Case 7, there is one previous touch point PP0, and two touch points C0 and C1 exist at the present time, and between the previous touch point PP0 and the current touch points TP0 and TP1. For accurate matching, the scale Dij, which represents the distance between the previous touch point PPi and the current temporary touch point TPj, is defined as in Equation 3.

Dij = | PPi-TPj |

For example, the touch point tracking unit 350 is a measure Dij representing the distance between the previous touch point PPi and the current temporary touch point TPj using Equation 3 in the case of Case 7, and the two D00 and D01. You can get the value. The touch point tracking unit 350 defines TP0 as a subsequent touch point of PP0 and TP1 as a new touch point because PP0 and TP0 are close when D00 is smaller than D01. The touch point tracker 350 may determine TP1 as a subsequent touch point of PP0 when D00 is not smaller than D01. The final touch points CP0 and CP1 are defined as in Equation 4.

CP0 = TP0 and CP1 = TP1, if D00 <D01

CP0 = TP1 and CP1 = TP0, otherwise

The touch point tracking unit 350 calculates CP0 = TP0 when D00 is less than D10 and calculates CP1 = TP0 when D00 is less than D10 in case of D10 and D10.

The touch point tracking unit 350 calculates D00 and D01 in case 11, and sets CP0 = TP0, CP1 = TP1 when D00 is less than D01, and CP0 = TP1, CP1 = TP0 when D00 is not less than D01. Set it.

The touch point tracker 350 is a single touch at a previous sample instant, and in case of Case 8 where a touch of two fingers is currently generated, the touch point tracker 350 uses four row electrodes and four column electrode signals as shown in FIG. 10. Track location information (TP0, TP1, TP2, TP3) for the touch point. As an example, the four touch point information may include two actual touch positions TP0 and TP3 and two virtual touch positions TP1 and TP2. The touch point tracking unit 350 calculates a distance D0j between the previous touch point PP0 and the currently detected touch point TPi (i = 0, 1, 2, 3), and among the currently detected touch points TPi. The actual touch point associated with the previous touch point PP0 is calculated using Equation 5.

The touch point tracking unit 350 calculates the actual touch point CP0 associated with the previous touch point using Equation 5 when the case 8 has two fingers arranged diagonally, and the actual touch point associated with the current touch point. CP1 may be determined to be positioned diagonally to CP0, and the remaining points except for CP0 and CP1 may be determined as ghost touch points and removed.

11 is a diagram illustrating an example of an actual touch point from which a ghost touch point is removed.

Referring to FIG. 11, in case 8, when the actual touch point CP0 associated with the previous touch point is located at the upper left end (TP0), the touch point tracking unit 350 positions CP1 in a diagonal direction of CP0 (TP3). It is determined that it is, and the remaining points except for CP0, CP1 may be determined as a ghost touch point and removed (a).

The touch point tracking unit 350 determines that the CP1 is positioned in the diagonal direction of the CP0 when the CP0 is positioned at the lower left end (TP1), and removes the remaining points except for the CP0 and CP1 as ghost touch points. (B).

The touch point tracking unit 350 determines that the CP1 is positioned in the diagonal direction of the CP0 when the CP0 is positioned at the phase TP2 (TP1), and removes the remaining points except for the CP0 and CP1 as ghost touch points. (C).

The touch point tracking unit 350 determines that the CP1 is positioned in the diagonal direction of the CP0 when the CP0 is located at the lower right end (TP3), and removes the remaining points except for the CP0 and CP1 as ghost touch points. (D)

The touch point tracking unit 350 may move the case 12 in a state where two fingers are touched, and thus, as in Case 8, the touch point tracking unit 350 may remove the ghost touch from the detected touch point information to track the exact position of the actual touch point.

As described above, the multi-touch sensing device and method according to an embodiment of the present invention cluster the row and column electrode data of the touch screen and apply the weighted average algorithm to each cluster to obtain the center position by using the touch point information. By detecting and removing the ghost touch information from the detected touch point information it is possible to accurately detect the multi-touch.

Meanwhile, the method according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the media may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks, such as floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

As described above, the present invention has been described by specific embodiments such as specific components and the like. For those skilled in the art to which the present invention pertains, various modifications and variations are possible.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all of the equivalents or equivalents of the claims as well as the claims to be described later will belong to the scope of the present invention. .

1 is a diagram illustrating a position detection principle of a projection capacitive touch screen using a line scanning method.

2 is a diagram illustrating a problem of the projected capacitance touch screen during multi-touch.

3 is a diagram illustrating a configuration of a multi-touch sensing device of a touch screen according to an embodiment of the present invention.

4 is a diagram illustrating an operation flow of a multi-touch sensing method of a touch screen according to an embodiment of the present invention.

5 shows raw data with offset, offset data, and offset-free data.

6 is a flowchart of a touch area identification algorithm for row or column electrode data according to an embodiment of the present invention.

7 is a diagram illustrating an example of detecting a position of a touch point by clustering row or column electrode data.

8 is a diagram illustrating a touch point detection result detected according to a touch point detection algorithm when two fingers touch each other.

9 is a flowchart of a touch point tracking algorithm according to an embodiment of the present invention.

10 is a diagram illustrating an example of an actual touch position and a virtual touch position.

11 is a diagram illustrating an example of an actual touch point from which a ghost touch point is removed.

<Explanation of symbols for the main parts of the drawings>

300: multi-touch detection device

310: data acquisition unit

320: noise canceling unit

330: offset remover

340: touch point detector

350: touch point tracking unit

Claims (11)

A touch point detector configured to group each row electrode data and column electrode data of the touch screen to detect touch point information on the touch screen; And Touch point tracking unit for tracking the actual touch point actually touched by the user in the detected touch point information Multi-touch detection device comprising a. The method of claim 1, The touch point detector, Multi-touch sensing for binarizing each row electrode data and column electrode data of the touch screen according to a predetermined reference value, clustering the binarized data for each level and applying a weighted average algorithm to each cluster to detect the touch point information Device. The method of claim 1, A data acquisition unit for acquiring the row electrode data and the column electrode data according to a touch operation of the user with respect to the touch screen; A noise removing unit for removing noise with respect to the obtained row electrode data and column electrode data; And An offset remover that removes offset data from the row electrode data and the column electrode data from which the noise is removed; More, The touch point detector, And detecting the touch point information by using the row electrode data and the column electrode data from which the noise and the offset are removed. The method of claim 1, The touch point tracking unit, And tracking the actual touch point according to a result of comparing the detected touch point information with past touch position information, and assigning an ID to the tracked real touch point. The method of claim 4, wherein The touch point tracking unit, And removing ghost touch information detected by the unnecessary touch that is not related to the actual touch point from the detected touch point information. Grouping each of the row electrode data and the column electrode data of the touch screen to detect touch point information on the touch screen; And Tracking the actual touch point actually touched by the user in the detected touch point information. The method of claim 6, Detecting the touch point information, And dividing the row electrode data and the column electrode data according to a predetermined reference value, clustering the binarized data for each level, and applying a weighted average algorithm to each cluster to detect the touch point information. The method of claim 6, Detecting the touch point information, And detecting the touch point information after removing noise and offset from the row electrode data and the column electrode data. The method of claim 6, Tracking the actual touch point, And detecting an actual touch point actually touched according to a result of comparing the detected touch point information with past touch position information, and assigning an ID to the tracked real touch point. 10. The method of claim 9, Tracking the actual touch point, And removing, as the virtual touch information, ghost touch information detected due to unnecessary contact that is not related to the actual touch point in the detected touch point information. A computer readable recording medium having recorded thereon a program for performing the method of claim 6.

Images