TWI843345B - Lagrangian touch trajectory simulation method, touch module and information processing device - Google Patents

Abstract

A Lagrangian touch trajectory fitting method includes: periodically reading a touch point coordinate from a sensing array; taking a current touch point coordinate and the coordinates of the previous touch point The midpoint has a first horizontal coordinate ( _xc ) and a first vertical coordinate ( _yc ). Substituting the first horizontal coordinate ( _xc ) into a first Lagrange polynomial to obtain a second vertical coordinate ( ), and substituting the first vertical coordinate (y _c ) into a second Lagrange polynomial to obtain a second horizontal coordinate ( ); and according to the current touch point coordinates , the coordinates of the previous touch point and the coordinates of the previous touch point The horizontal and vertical relative position relationship determines the coordinates of an insertion point as ( )or( ).

Description

Lagrangian touch trajectory simulation method, touch module and information processing device

The present invention relates to touch data processing, and more particularly to a touch track fitting scheme.

Existing touch technology adds insertion points between multiple sensed touch points to increase touch reporting points. For example, a third-order Bessel algorithm is used to calculate four known points to generate a simulated orbit, and then an insertion point is generated on the simulated orbit.

However, the Bessel algorithm has probabilistic burrs, and its fitting trajectory has insufficient curvature and inverse curvature. In addition, the Bessel algorithm can only interpolate within the known touch point interval and cannot predict the coordinates of future touch points.

To solve the above problems, a novel touch trajectory fitting method is urgently needed in this field.

One purpose of the present invention is to disclose a Lagrangian touch trajectory fitting method, which can generate insertion points by three touch points to reduce the amount of calculation.

Another object of the present invention is to disclose a Lagrangian touch trajectory fitting method, which can determine the coordinates of the insertion point and predict the coordinates of the next touch point and the next insertion point by a Lagrangian polynomial.

Another object of the present invention is to disclose a Lagrangian touch trajectory fitting method, which can generate coordinates of multiple next touch points according to a Lagrangian polynomial and the coordinates of the three latest touch points of multiple finger trajectories in the application of multi-finger touch operation, and find the closest ones to each next touch point in the finger trajectories to determine the corresponding finger trajectory of each next touch point.

Another object of the present invention is to disclose a touch module that can reduce the amount of calculation, optimize the curvature of the fitting trajectory, and predict the position of the next touch point through the aforementioned touch trajectory fitting method.

Another object of the present invention is to disclose an information processing device that can reduce the amount of calculation of the fitting trajectory, optimize the curvature of the fitting trajectory, and predict the position of the next touch point through the aforementioned touch module.

To achieve the above-mentioned purpose, a Lagrangian touch trajectory fitting method is proposed, which is implemented by a control circuit. The method includes: periodically reading a touch point coordinate from a sensing array; taking a current touch point coordinate and the coordinates of the previous touch point The midpoint has a first horizontal coordinate ( _xc ) and a first vertical coordinate ( _yc ). Substituting the first horizontal coordinate ( _xc ) into a first Lagrange polynomial to obtain a second vertical coordinate ( ), and substituting the first vertical coordinate (y _c ) into a second Lagrange polynomial to obtain a second horizontal coordinate ( ); and according to the current touch point coordinates , the coordinates of the previous touch point and the coordinates of the previous touch point The horizontal and vertical relative position relationship determines the coordinates of an insertion point as ( )or( ), where The insertion point coordinates are ;when The insertion point coordinates are ( ); and The insertion point coordinates are and( ) and ( ) is closer.

In one embodiment, the first Lagrangian polynomial is based on the current touch point coordinates , the coordinates of the previous touch point and the coordinates of the previous touch point A polynomial with the horizontal coordinate (x) as a variable is generated, and the second Lagrangian polynomial is based on the coordinates of the current touch point , the coordinates of the previous touch point and the coordinates of the previous touch point Generates a polynomial with the vertical coordinate (y) as a variable.

In one embodiment, the Lagrangian touch control trajectory fitting method further includes: presetting a valve value and a difference Let the x coordinate of the next touch point be ; and let the y coordinate of the next touch point be ,in is the first Lagrangian polynomial.

In one embodiment, the Lagrangian touch trajectory fitting method further comprises: finding a finger trajectory corresponding to the next touch point in a plurality of finger trajectories The nearest finger trajectory to determine the next touch point of the attributed finger track.

In one embodiment, the Lagrangian touch trajectory fitting method further comprises: setting the x coordinate of the next insertion point to The y coordinate is .

In one embodiment, the Lagrangian touch trajectory fitting method further includes: the control circuit sequentially transmits the current touch point coordinates and the insertion point coordinates to an application processor via a communication interface.

To achieve the aforementioned object, the present invention further proposes a touch module having a control circuit and a sensor array, wherein the control circuit executes the aforementioned touch track fitting method.

In possible embodiments, the sensing array may be a capacitive sensing array, an ultrasonic sensing array, a pressure sensing array or an optical sensing array.

To achieve the aforementioned object, the present invention further proposes an information processing device having the aforementioned touch module and an application processor.

In possible embodiments, the information processing device may be a smart phone, a portable computer or a car computer.

In order to enable the Review Committee to further understand the structure, features, purpose, and advantages of the present invention, the following are attached with drawings and detailed descriptions of preferred specific embodiments.

The principle of the present invention is to use a second-order Lagrange polynomial to generate the coordinates of an insertion point between the coordinates of three touch points and predict the coordinates of the next touch point, the contents of which are as follows:

(I) Generation of insertion points:

The coordinates of three touch points are known First calculate two possible insertion points ,in , f(x) is the first Lagrangian polynomial, g(y) is the second Lagrangian polynomial, , .

Then, if satisfied Dissatisfied The insertion point coordinates are ;

If satisfied And not satisfied , then the insertion point coordinates are as well as

like Satisfied, then Pick closer.

(ii) Coordinate prediction of the next touch point:

Take the insertion point coordinates For example, set the valve value , The predicted x coordinate of the next touch point is

;

The y coordinate of the next touch point is ;

Take the x coordinate of the next insertion point as The y coordinate of the insertion point is When the insertion point coordinates are The same applies to time.

In addition, in the application of multi-finger touch operation, the present invention obtains the next touch point After that, you can find the next touch point in multiple finger trajectories. The nearest finger trajectory to determine the next touch point of the attributed finger track.

Please refer to FIG1, which shows a block diagram of an embodiment of the touch module of the present invention. As shown in FIG2, a touch module 100 has a control circuit 110 and a sensing array 120, and the control circuit 110 has a read circuit 111, a memory 112, a control unit 113 and a communication interface 114, wherein the read circuit 111 is used to read the touch point data from the sensing array 120, the memory 112 stores the touch point data, the control unit 113 executes a Lagrangian touch trajectory fitting program, and the communication interface 114 is used to communicate with an application processor. In addition, the sensing array 120 may be a capacitive sensing array, an ultrasonic sensing array, a pressure sensing array, or an optical sensing array.

The Lagrangian touch trajectory fitting procedure includes the following steps:

(i) periodically reading the touch point coordinates from the sensing array 120 by the readout circuit 111;

(ii) The control unit 113 determines the coordinates of the current touch point , the coordinates of the previous and next touch points and the coordinates of the previous touch point Generate a first Lagrangian polynomial with the horizontal coordinate (x) as a variable and a second Lagrangian polynomial with the vertical coordinate (y) as a variable; take the middle point between the current touch point coordinate and the previous touch point coordinate, the middle point has a first horizontal coordinate ( _xc ) and a first vertical coordinate ( _yc ), substitute the first horizontal coordinate ( _xc ) into the first Lagrangian polynomial to obtain a second vertical coordinate ( ), and substitute the first vertical coordinate (y _c ) into the second Lagrange polynomial to obtain a second horizontal coordinate ( );as well as

(iii) Determine the coordinates of an insertion point according to the horizontal and vertical relative position relationship of the current touch point coordinates, the previous touch point coordinates, and the previous previous touch point coordinates ( )or( ), where The insertion point coordinates are ;when The insertion point coordinates are ( ); and The insertion point coordinates are and( ) and ( ) is closer.

In addition, the Lagrangian touch trajectory fitting procedure may further include a step of predicting the coordinates of the next touch point and the next insertion point:

(IV) Setting the valve value , Let the x coordinate of the next touch point be

;and

Let the y coordinate of the next touch point be ,in is the first Lagrangian polynomial; and

(V) Let the x coordinate of the next insertion point be The y coordinate is

.

In addition, in the application of multi-finger touch operation, the present invention obtains the next touch point After that, you can find the next touch point in multiple finger trajectories. The nearest finger trajectory to determine the next touch point According to this, the present invention can optimize the simulation effect of a touch track.

As can be seen from the above, the present invention discloses a Lagrangian touch trajectory fitting method. Please refer to FIG. 2, which shows a flow chart of an embodiment of the Lagrangian touch trajectory fitting method of the present invention, which is implemented by a control circuit. As shown in FIG. 2, the method includes: periodically reading a touch point coordinate from a sensing array (step a); taking a current touch point coordinate and the coordinates of the previous touch point The midpoint has a first horizontal coordinate ( _xc ) and a first vertical coordinate ( _yc ). Substituting the first horizontal coordinate ( _xc ) into a first Lagrange polynomial to obtain a second vertical coordinate ( ), and substituting the first vertical coordinate (y _c ) into a second Lagrange polynomial to obtain a second horizontal coordinate ( )(step b); and according to the current touch point coordinates , the coordinates of the previous touch point and the coordinates of the previous touch point The horizontal and vertical relative position relationship determines the coordinates of an insertion point as ( )or( ), where The insertion point coordinates are ;when The insertion point coordinates are ( ); and The insertion point coordinates are and( ) and ( ) is closer (step c).

In step a, the sensing array may be a capacitive sensing array, an ultrasonic sensing array, a pressure sensing array or an optical sensing array.

In step b, the first Lagrangian polynomial is based on the current touch point coordinates , the coordinates of the previous touch point and the coordinates of the previous touch point A polynomial with the horizontal coordinate (x) as a variable is generated, and the second Lagrangian polynomial is based on the coordinates of the current touch point , the coordinates of the previous touch point and the coordinates of the previous touch point Generates a polynomial with the vertical coordinate (y) as a variable.

In addition, the Lagrangian touch trajectory fitting method may further include a coordinate prediction step of the next touch point:

Default value and a difference Let the x coordinate of the next touch point be

;and

Let the y coordinate of the next touch point be ,in is the first Lagrangian polynomial.

In addition, the Lagrangian touch trajectory fitting method may further include a coordinate prediction step of the next insertion point:

Let the x coordinate of the next insertion point be The y coordinate is

.

In addition, in the application of multi-finger touch operation, the Lagrangian touch trajectory fitting method may further include:

Find the next touch point in multiple finger trajectories The nearest finger trajectory to determine the next touch point of the attributed finger track.

In addition, after obtaining the insertion point coordinates, the control circuit can sequentially transmit the current touch point coordinates and the insertion point coordinates to an application processor via a communication interface.

According to the above description, the present invention further proposes an information processing device. Please refer to FIG. 3, which shows a block diagram of an embodiment of the information processing device of the present invention. As shown in FIG. 3, an information processing device 200 has a touch module 210 and an application processor 220, wherein the touch module 210 is implemented by the touch module 100, and the application processor 220 is used to periodically receive the current touch point coordinates and insertion point coordinates output by the touch module 210.

In addition, the information processing device 200 may be a smart phone, a portable computer or a car computer.

Through the above disclosed design, the present invention has the following advantages:

1. The Lagrangian touch trajectory fitting method of the present invention can generate insertion points by three touch points to reduce the amount of calculation.

2. The Lagrangian touch trajectory fitting method of the present invention can determine the coordinates of the insertion point and predict the coordinates of the next touch point and the next insertion point by a Lagrangian polynomial.

3. The Lagrangian touch trajectory fitting method of the present invention can generate coordinates of multiple next touch points according to a Lagrangian polynomial and the coordinates of the three latest touch points of multiple finger trajectories in the application of multi-finger touch operation, and find the closest ones to each next touch point in the finger trajectories to determine the corresponding finger trajectory of each next touch point.

4. The touch module of the present invention can reduce the amount of calculation, optimize the curvature of the fitting trajectory, and predict the position of the next touch point through the aforementioned touch trajectory fitting method.

5. The information processing device of the present invention can reduce the amount of calculation of the fitting trajectory, optimize the curvature of the fitting trajectory, and predict the position of the next touch point through the aforementioned touch module.

The invention disclosed in this case is a preferred embodiment. Any partial changes or modifications that are derived from the technical concept of this case and are easily inferred by people familiar with the art do not deviate from the scope of the patent rights of this case.

In summary, this case shows that its purpose, means and effects are all different from the known technology, and it is the first invention that is practical and indeed meets the patent requirements for invention. We sincerely request the review committee to examine this carefully and grant a patent as soon as possible to benefit the society. This is our utmost prayer.

100:Touch module

110: Control circuit

111: Read out circuit

112: Memory

113: Control unit

114: Communication interface

120:Sensor array

200: Information processing device

210: Touch Module

220: Application Processor

Step a: Periodically read the coordinates of a touch point from a sensing array

Step b: Get the coordinates of the current touch point

and the coordinates of the previous touch point The midpoint has a first horizontal coordinate ( _xc ) and a first vertical coordinate ( _yc ). Substituting the first horizontal coordinate ( _xc ) into a first Lagrange polynomial to obtain a second vertical coordinate ( ), and substituting the first vertical coordinate (y _c ) into a second Lagrange polynomial to obtain a second horizontal coordinate ( ).

Step c: According to the current touch point coordinates , the coordinates of the previous touch point and the coordinates of the previous touch point The horizontal and vertical relative position relationship determines the coordinates of an insertion point as ( )or( ), where The insertion point coordinates are ;when The insertion point coordinates are ( ); and The insertion point coordinates are and( ) and ( ) Closer

Fig. 1 is a block diagram of a touch module according to an embodiment of the present invention. Fig. 2 is a flow chart of a touch track fitting method according to an embodiment of the present invention. Fig. 3 is a block diagram of an information processing device according to an embodiment of the present invention.

Step a: Periodically read the coordinates of a touch point from a sensing array

)，及將該第一垂直座標(y_c)代入一第二拉格朗日多項式以獲得一第二水平座標(

) Step b: Take the middle point between the current touch point coordinate (x ₃ , y ₃ ) and the previous touch point coordinate (x ₂ , y ₂ ), the middle point has a first horizontal coordinate (x _c ) and a first vertical coordinate (y _c ), substitute the first horizontal coordinate (x _c ) into a first Lagrange polynomial to obtain a second vertical coordinate (

), and substituting the first vertical coordinate (y _c ) into a second Lagrange polynomial to obtain a second horizontal coordinate (

)

)或(

,y_c)，其中，當(x₁-x₂)×(x₂-x₃)大於0且(y₁-y₂)×(y₂-y₃)不大於0，則 插入點座標取(x_c ,

)；當(y₁-y₂)×(y₂-y₃)大於0且(x₁-x₂)×(x₂-x₃)不大於0，則插入點座標取(

,y_c)；及當(y₁-y₂)×(y₂-y₃)大於0且(x₁-x₂)×(x₂-x₃)大於0，則插入點座標取(x_c ,

)和(

,y_c)中與(x_c ,y_c)較近者 Step c: Determine the coordinates of an insertion point (x _c , y ₃ ) according to the horizontal and vertical relative position relationship between the current touch point coordinates (x ₃ , y 3 ), the previous touch point coordinates (x ₂ , y ₂ ) and the previous previous touch point coordinates (x ₁ , y ₁ )

)or(

, y _c ), where (x ₁ -x ₂ )×(x ₂ -x ₃ ) is greater than 0 and (y ₁ -y ₂ )×(y ₂ -y ₃ ) is not greater than 0, the insertion point coordinates are (x _c ,

); when (y ₁ -y ₂ )×(y ₂ -y ₃ ) is greater than 0 and (x ₁ -x ₂ )×(x ₂ -x ₃ ) is not greater than 0, the insertion point coordinates are (

, y _c ); and when (y ₁ -y ₂ )×(y ₂ -y ₃ ) is greater than 0 and (x ₁ -x ₂ )×(x ₂ -x ₃ ) is greater than 0, the insertion point coordinates are (x _c ,

)and(

, y _c ) that is closer to (x _c , y _c )

Claims (17)

A Lagrangian touch trajectory fitting method is implemented by a control circuit. The method includes: periodically reading a touch point coordinate from a sensing array; taking a midpoint between a current touch point coordinate (x ₃ , y ₃ ) and a previous touch point coordinate (x ₂ , y ₂ ), the midpoint having a first horizontal coordinate (x _c ) and a first vertical coordinate (y _c ), substituting the first horizontal coordinate (x _c ) into a first Lagrangian polynomial to obtain a second vertical coordinate (

), and substituting the first vertical coordinate (y _c ) into a second Lagrange polynomial to obtain a second horizontal coordinate (

); and according to the horizontal and vertical relative position relationship between the current touch point coordinates (x ₃ , y ₃ ), the previous touch point coordinates (x ₂ , y ₂ ) and the previous previous touch point coordinates (x ₁ , y ₁ ), the coordinates of an insertion point are determined as (x _c ,

)or(

, y _c ), where (x ₁ -x ₂ )×(x ₂ -x ₃ ) is greater than 0 and (y ₁ -y ₂ )×(y ₂ -y ₃ ) is not greater than 0, the insertion point coordinates are (x _c ,

); when (y ₁ -y ₂ )×(y ₂ -y ₃ ) is greater than 0 and (x ₁ -x ₂ )×(x ₂ -x ₃ ) is not greater than 0, the insertion point coordinates are (

, y _c ); and when (y ₁ -y ₂ )×(y ₂ -y ₃ ) is greater than 0 and (x ₁ -x ₂ )×(x ₂ -x ₃ ) is greater than 0, the insertion point coordinates are (x _c ,

)and(

, y _c ) that is closer to (x _c , y _c ); wherein the first Lagrangian polynomial is a polynomial with the horizontal coordinate (x) as a variable generated according to the current touch point coordinates (x ₃ , y ₃ ), the previous touch point coordinates (x ₂ , y ₂ ) and the previous previous touch point coordinates (x ₁ , y ₁ ), and the second Lagrangian polynomial is a polynomial with the vertical coordinate (y) as a variable generated according to the current touch point coordinates (x ₃ , y ₃ ), the previous touch point coordinates (x ₂ , y ₂ ) and the previous previous touch point coordinates (x ₁ , y ₁ ). The Lagrangian touch trajectory fitting method as described in claim 1 further comprises: presetting a valve value △ x _h and a difference value △ x =|( x ₃ - x ₂ )-( x ₂ - x ₁ )| , and setting the x coordinate of the next touch point to

; and let the y coordinate of the next touch point be

, where f (.) is the first Lagrangian polynomial. The Lagrangian touch trajectory fitting method as described in claim 2 further comprises: finding a point in the plurality of finger trajectories that corresponds to the next touch point (

,

) The nearest finger trajectory to determine the next touch point (

,

)'s attributed finger track. The Lagrangian touch trajectory fitting method as described in claim 2 further comprises: setting the x coordinate of the next insertion point to

, the y coordinate is

The Lagrangian touch trajectory fitting method as described in claim 1 further includes: the control circuit sequentially transmits the current touch point coordinates and the insertion point coordinates to an application processor via a communication interface. A touch module has a control circuit and a sensing array, wherein the control circuit executes a Lagrangian touch trajectory fitting procedure, the procedure comprising: periodically reading a touch point coordinate from the sensing array; taking a midpoint between a current touch point coordinate (x ₃ , y ₃ ) and a previous touch point coordinate (x ₂ , y ₂ ), the midpoint having a first horizontal coordinate (x _c ) and a first vertical coordinate (y _c ), substituting the first horizontal coordinate (x _c ) into a first Lagrangian polynomial to obtain a second vertical coordinate (

), and substituting the first vertical coordinate (y _c ) into a second Lagrange polynomial to obtain a second horizontal coordinate (

); and according to the horizontal and vertical relative position relationship between the current touch point coordinates (x ₃ , y ₃ ), the previous touch point coordinates (x ₂ , y ₂ ) and the previous previous touch point coordinates (x ₁ , y ₁ ), the coordinates of an insertion point are determined as (x _c ,

)or(

, y _c ), where (x ₁ -x ₂ )×(x ₂ -x ₃ ) is greater than 0 and (y ₁ -y ₂ )×(y ₂ -y ₃ ) is not greater than 0, the insertion point coordinates are (x _c ,

); when (y ₁ -y ₂ )×(y ₂ -y ₃ ) is greater than 0 and (x ₁ -x ₂ )×(x ₂ -x ₃ ) is not greater than 0, the insertion point coordinates are (

, y _c ); and when (y ₁ -y ₂ )×(y ₂ -y ₃ ) is greater than 0 and (x ₁ -x ₂ )×(x ₂ -x ₃ ) is greater than 0, the insertion point coordinates are (x _c ,

)and(

, y _c ) that is closer to (x _c , y _c ); wherein the first Lagrangian polynomial is a polynomial with the horizontal coordinate (x) as a variable generated according to the current touch point coordinates (x ₃ , y ₃ ), the previous touch point coordinates (x ₂ , y ₂ ) and the previous previous touch point coordinates (x ₁ , y ₁ ), and the second Lagrangian polynomial is a polynomial with the vertical coordinate (y) as a variable generated according to the current touch point coordinates (x ₃ , y ₃ ), the previous touch point coordinates (x ₂ , y ₂ ) and the previous previous touch point coordinates (x ₁ , y ₁ ). The touch module as described in claim 6, wherein the Lagrangian touch trajectory fitting procedure further comprises: presetting a valve value △ x _h and a difference value △ x =|( x ₃ - x ₂ )-( x ₂ - x ₁ )| , and setting the x coordinate of the next touch point to

; and let the y coordinate of the next touch point be

, where f (.) is the first Lagrangian polynomial. The touch module as claimed in claim 7, wherein the Lagrangian touch trajectory fitting procedure further comprises: finding a point in the plurality of finger trajectories that corresponds to the next touch point (

,

) The nearest finger trajectory to determine the next touch point (

,

)'s attributed finger track. The touch module as claimed in claim 7, wherein the Lagrangian touch trajectory fitting procedure further comprises: setting the x coordinate of the next insertion point to

, the y coordinate is

The touch module as described in claim 6, wherein the Lagrangian touch trajectory fitting procedure further comprises: the control circuit sequentially transmits the current touch point coordinates and the insertion point coordinates to an application processor via a communication interface. A touch control module as described in claim 6, wherein the sensing array is a sensing array selected from a group consisting of a capacitive sensing array, an ultrasonic sensing array, a pressure sensing array, and an optical sensing array. An information processing device has a touch module and an application processor, wherein the touch module has a control circuit and a sensing array, and is characterized in that the control circuit executes a Lagrangian touch trajectory fitting program, the program comprising: periodically reading a touch point coordinate from the sensing array; taking a midpoint between a current touch point coordinate (x ₃ , y ₃ ) and a previous touch point coordinate (x ₂ , y ₂ ), the midpoint having a first horizontal coordinate (x _c ) and a first vertical coordinate (y _c ), substituting the first horizontal coordinate (x _c ) into a first Lagrangian polynomial to obtain a second vertical coordinate (

), and substituting the first vertical coordinate (y _c ) into a second Lagrange polynomial to obtain a second horizontal coordinate (

); and according to the horizontal and vertical relative position relationship between the current touch point coordinates (x ₃ , y ₃ ), the previous touch point coordinates (x ₂ , y ₂ ) and the previous previous touch point coordinates (x ₁ , y ₁ ), the coordinates of an insertion point are determined as (x _c ,

)or(

, y _c ), where (x ₁ -x ₂ )×(x ₂ -x ₃ ) is greater than 0 and (y ₁ -y ₂ )×(y ₂ -y ₃ ) is not greater than 0, the insertion point coordinates are (x _c ,

); when (y ₁ -y ₂ )×(y ₂ -y ₃ ) is greater than 0 and (x ₁ -x ₂ )×(x ₂ -x ₃ ) is not greater than 0, the insertion point coordinates are (

, y _c ); and when (y ₁ -y ₂ )×(y ₂ -y ₃ ) is greater than 0 and (x ₁ -x ₂ )×(x ₂ -x ₃ ) is greater than 0, the insertion point coordinates are (x _c ,

)and(

, y _c ) that is closer to (x _c , y _c ); wherein the first Lagrangian polynomial is a polynomial with the horizontal coordinate (x) as a variable generated according to the current touch point coordinates (x ₃ , y ₃ ), the previous touch point coordinates (x ₂ , y ₂ ) and the previous previous touch point coordinates (x ₁ , y ₁ ), and the second Lagrangian polynomial is a polynomial with the vertical coordinate (y) as a variable generated according to the current touch point coordinates (x ₃ , y ₃ ), the previous touch point coordinates (x ₂ , y ₂ ) and the previous previous touch point coordinates (x ₁ , y ₁ ). The information processing device as claimed in claim 12, wherein the Lagrangian touch trajectory fitting procedure further comprises: presetting a valve value △ x _h and a difference value △ x =|( x ₃ - x ₂ )-( x ₂ - x ₁ )| , and setting the x coordinate of the next touch point to

; and let the y coordinate of the next touch point be

, where f (.) is the first Lagrangian polynomial. The information processing device as claimed in claim 13, wherein the Lagrangian touch trajectory fitting procedure further comprises: finding a point in the plurality of finger trajectories that corresponds to the next touch point (

,

) The nearest finger trajectory to determine the next touch point (

,

)'s attributed finger track. The information processing device as claimed in claim 13, wherein the Lagrangian touch trajectory fitting procedure further comprises: setting the x coordinate of the next insertion point to

, the y coordinate is

The information processing device as described in claim 12, wherein the Lagrangian touch trajectory fitting procedure further comprises: the control circuit sequentially transmits the current touch point coordinates and the insertion point coordinates to an application processor via a communication interface. The information processing device as described in claim 12 is a device selected from the group consisting of a smart phone, a portable computer and a car computer.

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