TWI553531B - Optical touch device and method for calculating coordinate of touch point - Google Patents

Description

Optical touch device and calculation method of touch point coordinates

The invention relates to an optical touch device and a calculation method of a touch point coordinate, in particular to an optical touch device and a touch point coordinate calculation method capable of avoiding offset of a touch track.

Since current consumer electronic products are designed in a light, thin, short, and small direction, there is no room for traditional input tools such as a mouse and a keyboard. With the advancement of optical touch device technology, optical touch has been widely used in various consumer electronic products, such as displays, All in One, mobile phones, and Personal Digital Assistant (PDA). The control device is used as a tool for inputting data. At present, the optical touch device has advantages of lower cost and easier achievement than other touch technologies, such as resistive, capacitive, ultrasonic or projected image, especially in the field of large-sized touch display.

The conventional optical touch device utilizes two image sensing units disposed oppositely to sense a touch point indicated by a touch object (eg, a finger or a stylus) on the indication plane. When the image sensing unit senses the touch object on the indication plane, the processing unit of the optical touch device can calculate the coordinates of the touch point indicated by the touch object. However, limited by the resolution capabilities of the image sensing unit, the optical touch device cannot be made too large.

Please refer to FIG. 1 , which is a schematic diagram of a prior art optical touch device 5 . As shown in FIG. 1 , the optical touch device 5 is provided with four image sensing units 52 , 54 , 56 , 58 in the middle of the indication plane 50 , wherein the image sensing units 52 , 58 are responsible for sensing the right half of the indication plane 50 . The touch sensing area, and the image sensing units 54, 56 are responsible for sensing the touch area of the left half of the indication plane 50. In this way, a large-sized optical touch application can be realized.

As shown in FIG. 1 , a central touch area 500 is defined between the image sensing units 52 , 54 , 56 , 58 , wherein the connection of the image sensing units 52 , 58 is one of the left borders 502 of the central touch area 500 . The connection between the image sensing units 54, 56 is a right border 504 of the central touch area 500. In general, the touch operation on the central touch area 500 can be sensed by the image sensing units 52, 58 or the image sensing units 54, 56. As shown in FIG. 1 , the touch track 60 is sensed by the image sensing units 54 , 56 , and the touch track 62 is sensed by the image sensing units 52 , 58 . For the image sensing units 54 and 56, the touch track 60 starts to shift when approaching the right border 504; for the image sensing units 52, 58, when the touch track 62 is near the left border 502, Will start to produce an offset. Therefore, the transition and connection of the touch track 60 and the touch track 62 in the central touch area 500 may occur, which may cause an unsmooth phenomenon, thereby affecting the look and feel in use.

The invention provides an optical touch device capable of avoiding offset of a touch track and a calculation method of the touch point coordinates to solve the above problems.

An optical touch device includes an indicating plane having a first side and a second side, the first side being opposite to the second side; a first image sense The measuring unit and the second image sensing unit are disposed at intervals on the first side; a third image sensing unit and a fourth image sensing unit are spaced apart from each other on the second side, the first The image sensing unit is opposite to the fourth image sensing unit, and the second image sensing unit is opposite to the third image sensing unit, the first image sensing unit, the second image sensing unit, and the third A central touch area is defined between the image sensing unit and the fourth image sensing unit; and a processing unit is electrically connected to the first image sensing unit, the second image sensing unit, and the third image The first image sensing unit senses a first image, and the second image sensing unit is configured to sense a touch image on the central touch area. The unit senses a second image, the first The image sensing unit senses a third image, and the fourth image sensing unit senses a fourth image; the processing unit calculates a first coordinate of a touch point according to the first image and the fourth image, Calculating a second coordinate of the touch point according to the second image and the third image, and The first coordinate and the second coordinate are integrated by a weight to calculate an output coordinate of the touch point.

The patent application scope of the present invention further discloses that the processing unit calculates the output coordinate of the touch point by the following formula: X _T = X ₁ × W + X ₂ × (1- W ); and Y _T = Y ₁ × W + Y ₂ ×(1- W ); where (X _T , Y _T ) represents the output coordinate, (X ₁ , Y ₁ ) represents the first coordinate, and (X ₂ , Y ₂ ) represents the second coordinate, And W represents the weight.

The connection between the first image sensing unit and the fourth image sensing unit is the first boundary of the central touch area, the second image sensing unit and the third image. The connection of the sensing unit is a second boundary of the central touch area, wherein the first touch line defines a first critical line and a second critical line, and the first critical line is at a threshold from the first boundary The second critical line is spaced from the second boundary by the threshold distance; when the touch point is between the first boundary and the first critical line, the weight is equal to 0; when the touch point is located at the first When the boundary between the second boundary and the second critical line is equal to 1; when the touch point is between the first critical line and the second critical line, the weight is equal to , d represents the distance between the touch point and the first boundary, T represents the threshold distance, and D represents the distance between the first boundary and the second boundary.

The method of the present invention further discloses that when the processing unit calculates N touch points according to the first image and the fourth image, and calculates M touch points according to the second image and the third image, The processing unit determines whether N is greater than M, and N and M are both positive integers; when N is greater than M, the processing unit calculates and outputs coordinates of the N touch points; when N is less than M, the processing unit calculates and outputs The coordinates of the M touch points.

The application scope of the present invention further discloses that when N is equal to M, the processing unit pairs the N touch points and the M touch points to obtain N pairs of touch points, and the processing unit integrates the weights. The coordinates of the N pairs of touch points to calculate N output coordinates of the N pairs of touch points.

The method of the present invention further discloses a method for calculating a touch point coordinate, which is applicable to an optical touch device, the optical touch device includes an indication plane, a first image sensing unit, and a second image sensing unit. a third image sensing unit and a fourth image sensing unit, the indicating plane having a first side and a second side, the first side being opposite to the second side, the first side The first image sensing unit is disposed on the first side of the second image sensing unit, and the third image sensing unit is disposed on the second side of the fourth image sensing unit. The first image sensing unit is opposite to the fourth image sensing unit, and the second image sensing unit is opposite to the third image sensing unit, the first image sensing unit, the second image sensing unit, and the A central touch area is defined between the third image sensing unit and the fourth image sensing unit, and the method for calculating the touch point coordinates includes: when a touch gesture is performed on the central touch area, the first An image sensing unit senses a first image, the second image sensing unit senses a second image, the third image sensing unit senses a third image, and the fourth image sensing unit senses a fourth image; calculating a first coordinate of a touch point according to the first image and the fourth image; calculating a second coordinate of the touch point according to the second image and the third image; and Weighting the first coordinate and the second coordinate to calculate The output coordinates of one touch point.

The patent application scope of the present invention further discloses that the output coordinate of the touch point is calculated by the following formula: X _T = X ₁ × W + X ₂ × (1- W ); and Y _T = Y ₁ × W + Y ₂ ×(1- W ); where (X _T , Y _T ) represents the output coordinate, (X ₁ , Y ₁ ) represents the first coordinate, (X ₂ , Y ₂ ) represents the second coordinate, and W Indicates the weight.

The connection between the first image sensing unit and the fourth image sensing unit is the first boundary of the central touch area, the second image sensing unit and the third image. The connection of the sensing unit is a second boundary of the central touch area, wherein the first touch line defines a first critical line and a second critical line, and the first critical line is at a threshold from the first boundary The second critical line is spaced from the second boundary by the threshold distance. When the touch point is between the first boundary and the first critical line, the weight is equal to 0; when the touch point is located at the first When the boundary between the second boundary and the second critical line is equal to 1; when the touch point is between the first critical line and the second critical line, the weight is equal to , d represents the distance between the touch point and the first boundary, T represents the threshold distance, and D represents the distance between the first boundary and the second boundary.

The method for calculating the touch point coordinates further includes calculating N touch points according to the first image and the fourth image, and according to the second image and the third The image calculates M touch points; determines whether N is greater than M, wherein N and M are positive integers; when N is greater than M, calculates and outputs coordinates of the N touch points; and when N is less than M, calculates And output the coordinates of the M touch points.

The method for calculating the touch point coordinates further includes: when N is equal to M, pairing the N touch points with the M touch points to obtain N pairs of touch points; And integrating the coordinates of the N pairs of touch points with the weight to calculate N output coordinates of the N pairs of touch points.

In summary, the present invention integrates two sets of coordinates of the touch points sensed by the two sets of image sensing units by using weights to calculate the output coordinates of the touch points acting on the central touch area. Therefore, the present invention can effectively prevent the touch track from being offset in the central touch area, so that the touch track does not have an unsmooth phenomenon in the central touch area.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

1, 5‧‧‧ optical touch device

10, 50‧‧‧ indicating plane

12‧‧‧First image sensing unit

14‧‧‧Second image sensing unit

16‧‧‧ Third image sensing unit

18‧‧‧Four image sensing unit

20‧‧‧Processing unit

30, 32, 34, 36, 38, 40, 42, 42a, 42b, 44, 44a, 44b‧‧‧ touch points

52, 54, 56, 58‧‧‧ image sensing unit

60, 62‧‧‧ touch track

100‧‧‧ first side

102‧‧‧Second side

104, 500‧‧‧ central touch area

106‧‧‧First border

108‧‧‧second border

110‧‧‧first critical line

112‧‧‧second critical line

114‧‧‧ Left touch area

116‧‧‧Right touch area

502‧‧‧left border

504‧‧‧Right border

I1‧‧‧ first image

I2‧‧‧second image

I3‧‧‧ third image

I4‧‧‧ fourth image

D, d, H‧‧‧ distance

L‧‧‧ length

W‧‧‧Width

O‧‧‧ coordinate origin

T‧‧‧ threshold distance

X-Y‧‧‧ Right Angle Coordinate System

θ _A , θ _B , θ _C , θ _D ‧‧‧ angle

△θ‧‧‧ angle threshold

S10-S14, S20-S30‧‧‧ steps

FIG. 1 is a schematic diagram of a prior art optical touch device.

FIG. 2 is a schematic diagram of an optical touch device according to an embodiment of the invention.

Fig. 3 is a functional block diagram of the optical touch device in Fig. 2.

Figure 4 is a schematic diagram of a touch point generated on a central touch area.

FIG. 5 is a schematic diagram illustrating how the threshold distance is set by the second image sensing unit and the third image sensing unit.

Figure 6 is a schematic diagram of two touch points generated on the central touch area.

Figure 7 is a schematic diagram of two touch points generated on the central touch area.

Figure 8 is a schematic diagram of two touch points generated on the central touch area.

FIG. 9 is a flow chart of a method for calculating a touch point coordinate according to an embodiment of the present invention.

FIG. 10 is a flowchart of a method for calculating a touch point coordinate according to another embodiment of the present invention.

Please refer to FIG. 2 and FIG. 3 , FIG. 2 is a schematic diagram of an optical touch device 1 according to an embodiment of the present invention, and FIG. 3 is a functional block diagram of the optical touch device 1 in FIG. 2 . As shown in FIG. 2 and FIG. 3 , the optical touch device 1 includes an indication plane 10 , a first image sensing unit 12 , a second image sensing unit 14 , and a third image sensing unit 16 . The fourth image sensing unit 18 and the processing unit 20 are electrically connected to the first image sensing unit 12, the second image sensing unit 14, the third image sensing unit 16, and the fourth image sensing. Unit 18.

In an actual application, the indication plane 10 can be a display panel (for example, a liquid crystal display panel), a whiteboard, a blackboard, a projection screen, or other plane for the user to perform a touch operation; the first image sensing unit 12 and the second image sense The measurement unit 14, the third image sensing unit 16 and the fourth image sensing unit 18 may be a Charge-coupled Device (CCD) sensor or a Complementary Metal-Oxide Semiconductor (CMOS). The sensor, but not limited thereto; the processing unit 20 can be a processor or controller having a data operation/processing function. In an actual application, a light emitting unit (for example, a light emitting diode) may be disposed beside the first image sensing unit 12, the second image sensing unit 14, the third image sensing unit 16, and the fourth image sensing unit 18. Or, a light bar is placed around the indicating plane 10 to provide the light required for a general touch operation. When the light emitting unit is disposed beside the first image sensing unit 12, the second image sensing unit 14, the third image sensing unit 16, and the fourth image sensing unit 18, a reflective border or light absorbing may be disposed around the indicating plane 10. Border, depending on the application.

The indicator plane 10 has a first side 100 and a second side 102, wherein the first side 100 is opposite the second side 102. The first image sensing unit 12 and the second image sensing unit 14 are disposed at intervals on the first side 100 , and the third image sensing unit 16 and the fourth image sensing unit 18 are spaced apart from each other on the second side 102 . The first image sensing unit 12 is opposite to the fourth image sensing unit 18, the second image sensing unit 14 is opposite to the third image sensing unit 16, and the first image sensing unit 12 and the second image sensing unit A central touch area 104 is defined between the unit 14 , the third image sensing unit 16 and the fourth image sensing unit 18 . In addition, the first image sensing unit 12 and the fourth The connection of the image sensing unit 18 is the first boundary 106 of the central touch area 104, and the connection between the second image sensing unit 14 and the third image sensing unit 16 is the second of the central touch area 104. Boundary 108.

The present invention can set the XY right angle coordinate system and its coordinate origin O as shown in FIG. 2, where L is the length of the indication plane 10 and W is the width of the indication plane 10. The coordinates of the first image sensing unit 12 can be represented as (X _A , Y _A ), the coordinates of the second image sensing unit 14 can be represented as (X _B , Y _B ), and the coordinates of the third image sensing unit 16 can be It is expressed as (X _C , Y _C ), and the coordinates of the fourth image sensing unit 18 can be expressed as (X _D , Y _D ). As shown in FIG. 2, when a touch gesture is performed on the central touch area 104 to generate a touch point 30, the first image sensing unit 12 can sense that the angle of the touch point 30 is θ. _A , the second image sensing unit 14 can sense that the angle of the touch point 30 is θ _B , and the third image sensing unit 16 can sense that the angle of the touch point 30 is θ _C and the fourth image The sensing unit 18 can sense that the angle with respect to the touch point 30 is θ _D . It should be noted that the angles θ _A , θ _B , θ _C , and θ _D can be easily calculated by those skilled in the art of optical touch technology, and are not described herein again. Then, the first image sensing unit 12 and the fourth image sensing unit 18 can be used for triangulation to calculate the coordinates (X _E , Y _E ) of the touch point 30 by using the following formula 1 or by using the second The image sensing unit 14 and the third image sensing unit 16 perform triangulation to calculate the coordinates (X _E , Y _E ) of the touch point 30 by the following formula 2.

Please refer to FIG. 4 , which is a schematic diagram of a touch point 32 generated on the central touch area 104 . As shown in FIG. 4, a first critical line 110 and a second critical line 112 are defined in the central touch area 104, wherein the first critical line 110 is separated from the first boundary 106 by a threshold distance T, and the second critical line 112 is also spaced from the second boundary 108 by a threshold distance T.

As shown in FIG. 4, when a touch gesture is performed on the central touch area 104 to generate a touch point 32, the first image sensing unit 12 senses a first image I1, and the second image sensing The unit 14 senses a second image I2, the third image sensing unit 16 senses a third image I3, and the fourth image sensing unit 18 senses a fourth image I4. Since only one touch point 32 is generated on the central touch area 104, only one corresponding light interception signal is sensed in the first image I1, the second image I2, the third image I3, and the fourth image I4. Then, the processing unit 20 calculates the first coordinate (X ₁ , Y ₁ ) of one of the touch points 32 according to the first image I1 and the fourth image I4 according to the first formula I, according to the second image I2 and the third image I3. Calculating the second coordinate (X ₂ , Y ₂ ) of one of the touch points 32 by using the above formula ₂ , and integrating the first coordinate (X ₁ , Y ₁ ) and the second coordinate (X ₂ , Y ₂ ) by a weight W To calculate the output coordinate (X _T , Y _T ) of one of the touch points 32.

In this embodiment, the processing unit 20 can calculate the output coordinates (X _T , Y _T ) of the touch point 32 by the following formula 3.

Further, the weight W can be set in the following manner. When the touch point 32 is located between the first boundary 106 and the first critical line 110, the weight W can be set equal to 0; when the touch point 32 is located between the second boundary 108 and the second critical line 112, the weight W Can be set equal to 1; when the touch point 32 is located between the first critical line 110 and the second critical line 112, the weight W can be set equal to Where d represents the distance between the touch point 32 and the first boundary 106, T represents the threshold distance described above, and D represents the distance between the first boundary 106 and the second boundary 108.

When the touch point 32 is located between the first boundary 106 and the first critical line 110, it indicates that the touch point 32 is too close to the first boundary 106, so the second image I2 and the third image I3 can be calculated second. The coordinates (X ₂ , Y ₂ ) serve as output coordinates (X _T , Y _T ) of the touch point 32 to prevent the touch track from shifting between the first boundary 106 and the first critical line 110. Similarly, when the touch point 32 is located between the second boundary 108 and the second critical line 112, it indicates that the touch point 32 is too close to the second boundary 108, and thus can be calculated according to the first image I1 and the fourth image I4. The first coordinate (X ₁ , Y ₁ ) is used as the output coordinate (X _T , Y _T ) of the touch point 32 to prevent the touch track from shifting between the second boundary 108 and the second critical line 112.

In the embodiment shown in FIG. 4, the touch point 32 is located between the first critical line 110 and the second critical line 112. Therefore, you can weight W= The first coordinate (X ₁ , Y ₁ ) and the second coordinate (X ₂ , Y ₂ ) are integrated into the above formula 3 to calculate the output coordinates (X _T , Y _T ) of the touch point 32. Therefore, the present invention can effectively prevent the touch track from being offset in the central touch area 104, so that the touch track does not have an unsmooth phenomenon in the central touch area 104.

It should be noted that when the touch point is generated on the left touch area 114 on the left side of the central touch area 104, the second image sensing unit 14 and the third image sensing unit 16 can be used in the general optical touch principle. Calculating the number and coordinates of the touch points; when the touch points are generated in the right touch area 116 on the right side of the central touch area 104, the first image sensing unit 12 and the fourth image sensing unit 18 can be used for general optics. The touch principle is used to calculate the number and coordinates of touch points.

Please refer to FIG. 5 , which is a schematic diagram illustrating how the threshold distance T is set by the second image sensing unit 14 and the third image sensing unit 16 . As shown in FIG. 5, the second image sensing unit 14 and the third image sensing unit 16 can be used for triangulation to calculate all available touch points, wherein the second image sensing unit 14 and the third image are The sensing angle of the sensing unit 16 ranges from 0 to 90 degrees, and the interval is 1 degree, but is not limited thereto. In the right triangle area, the available touch points are relatively dense, and the touch point distribution can be fan-shaped to the right. Therefore, the touch point offset in this triangular area will be severe. According to the actual touch accuracy requirement, an angle threshold Δθ can be taken as appropriate, and if the distance between the second image sensing unit 14 and the third image sensing unit 16 is H, the threshold distance T can be set to Tan△θ. For example, if the distance H between the second image sensing unit 14 and the third image sensing unit 16 is 120 cm, and the angle threshold Δθ is 10 degrees, the threshold distance T can be set to 10.57 cm.

In this embodiment, when all the touch points are located in the central touch area 104, the processing unit 20 calculates N touch points according to the first image I1 and the fourth image I4, and according to the first When the two images I2 and the third image I3 calculate M touch points, the processing unit 20 may first determine whether N is greater than M, where N and M are both positive integers. When N is greater than M, the processing unit 20 calculates and outputs the coordinates of the N touch points using Equation 1 above. When N is less than M, the processing unit 20 calculates and outputs the coordinates of the M touch points using Equation 2 above. When N is equal to M, the processing unit 20 first pairs the N touch points and the M touch points to obtain N pairs of touch points. Then, the processing unit 20 integrates the coordinates of the N pairs with the touch points by using the above-mentioned weights W to calculate the N output coordinates of the N pairs of touch points.

Please refer to FIG. 6. FIG. 6 is a schematic diagram of two touch points 34, 36 generated on the central touch area 104. As shown in FIG. 6, the two touch points 34 and 36 overlap each other in the first image I1 and the fourth image I4. Therefore, the processing unit 20 calculates only one touch according to the first image I1 and the fourth image I4. Point (ie, N=1). In addition, the two touch points 34 and 36 are not overlapped in the second image I2 and the third image I3. Therefore, the processing unit 20 can calculate two touch points according to the second image I2 and the third image I3 (ie, , M = 2). At this time, the processing unit 20 can directly calculate and output the coordinates of the two touch points 34, 36 by using the above formula 2. In this way, it is possible to avoid a case where a misjudgment occurs due to overlapping of a plurality of touch points.

Please refer to FIG. 7. FIG. 7 is a schematic diagram of two touch points 38, 40 generated on the central touch area 104. As shown in FIG. 7, the two touch points 38 and 40 overlap each other in the second image I2 and the third image I3. Therefore, the processing unit 20 calculates only one touch according to the second image I2 and the third image I3. Point (ie, M=1). In addition, the two touch points 38 and 40 are not overlapped in the first image I1 and the fourth image I4. Therefore, the processing unit 20 can calculate two touch points according to the first image I1 and the fourth image I4 (ie, , N=2). At this time, the processing unit 20 can directly calculate and output the coordinates of the two touch points 38, 40 by using the above formula 1. In this way, it is possible to avoid a case where a misjudgment occurs due to overlapping of a plurality of touch points.

Please refer to FIG. 8. FIG. 8 is a schematic diagram of two touch points 42 and 44 generated on the central touch area 104. As shown in FIG. 8, the two touch points 42 and 44 are not overlapped in the first image I1, the second image I2, the third image I3, and the fourth image I4, so the processing unit 20 is based on the first image. Two touch points 42a, 44a (ie, N=2) can be calculated for the I1 and the fourth image I4, and two touch points 42b, 44b can be calculated according to the second image I2 and the third image I3. (ie, M=2). At this time, the processing unit 20 can pair the touch points 42a, 44a, 42b, and 44b two by two according to the shortest distance between each two touch points to obtain two pairs of touch points. In the embodiment shown in FIG. 8, the touch points 42a, 42b are a pair, and the touch points 44a, 44b are a pair. Then, the processing unit 20 integrates the coordinates of the two pairs of touch points by using the above-mentioned weights W to calculate the two output coordinates of the two pairs of touch points. The two output coordinates are the output coordinates of the two touch points 42, 44.

Please refer to FIG. 9. FIG. 9 is a flow chart of a method for calculating a touch point coordinate according to an embodiment of the present invention. The calculation method of the touch point coordinates in FIG. 9 is applicable to the optical touch device 1 described above. In addition, the control logic of the calculation method of the touch point coordinates in FIG. 9 can be implemented by circuit design and software design. First, in step S10, when the touch gesture is performed on the central touch area 104, the first image sensing unit 12 senses the first image I1, and the second image sensing unit 14 senses the second image I2. The third image sensing unit 16 senses the third image I3, and the fourth image sensing unit 18 senses the fourth image I4. Then, step S12 is executed to calculate a first coordinate of the touch point according to the first image I1 and the fourth image I4, and calculate a second coordinate of the touch point according to the second image I2 and the third image I3. Finally, step S14 is performed to integrate the first coordinate and the second coordinate with weights to calculate the output coordinates of the touch point.

Please refer to FIG. 10 , which is a flowchart of a method for calculating a touch point coordinate according to another embodiment of the present invention. The calculation method of the touch point coordinates in FIG. 10 is applicable to the optical touch device 1 described above. In addition, the control logic of the calculation method of the touch point coordinates in FIG. 10 can be implemented by circuit design and software design. First, step S20 is performed to calculate N touch points according to the first image I1 and the fourth image I4, and M touch points are calculated according to the second image I2 and the third image I3, wherein N and M are positive Integer. Next, step S22 is performed to determine whether N is greater than M. When N is greater than M, step S24 is performed to calculate and output coordinates of the N touch points. When N is less than M, step S26 is performed to calculate and output the coordinates of the M touch points. When N is equal to M, step S28 is performed to pair N touch points and M touch points to obtain N pairs of touch points. Then, In step S30, the coordinates of the N pairs of touch points are integrated by weights to calculate N output coordinates of the N pairs of touch points.

It should be noted that other working principles of the calculation method of the touch point coordinates of the present invention are as described above, and are not described herein again.

In summary, the present invention integrates two sets of coordinates of the touch points sensed by the two sets of image sensing units by using weights to calculate the output coordinates of the touch points acting on the central touch area. Therefore, the present invention can effectively prevent the touch track from being offset in the central touch area, so that the touch track does not have an unsmooth phenomenon in the central touch area.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

1‧‧‧Optical touch device

10‧‧‧ indicating plane

12‧‧‧First image sensing unit

14‧‧‧Second image sensing unit

16‧‧‧ Third image sensing unit

18‧‧‧Four image sensing unit

32‧‧‧ Touch points

100‧‧‧ first side

102‧‧‧Second side

104‧‧‧Central touch area

106‧‧‧First border

108‧‧‧second border

110‧‧‧first critical line

112‧‧‧second critical line

114‧‧‧ Left touch area

116‧‧‧Right touch area

I1‧‧‧ first image

I2‧‧‧second image

I3‧‧‧ third image

I4‧‧‧ fourth image

D, d‧‧‧ distance

L‧‧‧ length

W‧‧‧Width

O‧‧‧ coordinate origin

T‧‧‧ threshold distance

X-Y‧‧‧ Right Angle Coordinate System

Claims (10)

An optical touch device includes: an indicating plane having a first side and a second side, the first side being opposite to the second side; a first image sensing unit and a second image The sensing unit is disposed at intervals on the first side; a third image sensing unit and a fourth image sensing unit are spaced apart from each other on the second side, the first image sensing unit and the first The second image sensing unit is opposite to the third image sensing unit, and the first image sensing unit, the second image sensing unit, the third image sensing unit, and the first image sensing unit are opposite to the third image sensing unit. A central touch area is defined between the four image sensing units; and a processing unit is electrically connected to the first image sensing unit, the second image sensing unit, the third image sensing unit, and the fourth An image sensing unit, wherein the first image sensing unit senses a first image and the second image sensing unit senses a second image when a touch gesture is performed on the central touch area The third image sensing unit senses a third And the fourth image sensing unit senses a fourth image; the processing unit calculates a first coordinate of one touch point according to the first image and the fourth image, according to the second image and the third image The image calculates a second coordinate of the touch point, and integrates the first coordinate and the second coordinate with a weight to calculate an output coordinate of the touch point. The optical touch device of claim 1, wherein the processing unit calculates the output coordinate of the touch point by the following formula: X _T = X ₁ × W + X ₂ × (1- W ); and Y _T = Y ₁ × W + Y ₂ × (1- W ); where (X _T , Y _T ) represents the output coordinate, (X ₁ , Y ₁ ) represents the first coordinate, and (X ₂ , Y ₂ ) represents The second coordinate, and W represents the weight. The optical touch device of claim 2, wherein the connection between the first image sensing unit and the fourth image sensing unit is a first boundary of the central touch area, and the second image sensing unit The connection with the third image sensing unit is a second boundary of the central touch area, wherein the first touch line defines a first critical line and a second critical line, and the first critical line and the first a boundary is separated from a threshold distance, the second critical line is spaced from the second boundary by the threshold distance; when the touch point is between the first boundary and the first critical line, the weight is equal to 0; When the handle is located between the second boundary and the second critical line, the weight is equal to 1; when the touch point is between the first critical line and the second critical line, the weight is equal to , d represents the distance between the touch point and the first boundary, T represents the threshold distance, and D represents the distance between the first boundary and the second boundary. The optical touch device of claim 1, wherein the processing unit calculates N touch points according to the first image and the fourth image, and calculates M according to the second image and the third image. When the touch point is used, the processing unit determines whether N is greater than M, and N and M are both positive integers; when N is greater than M, the processing unit calculates and outputs coordinates of the N touch points; when N is less than M, the processing unit The processing unit calculates and outputs coordinates of the M touch points. The optical touch device of claim 4, wherein when N is equal to M, the processing unit pairs the N touch points and the M touch points to obtain N pairs of touch points. The unit integrates the coordinates of the N pairs of touch points with the weight to calculate N output coordinates of the N pairs of touch points. A method for calculating a touch point coordinate is applicable to an optical touch device. The optical touch device includes an indication plane, a first image sensing unit, a second image sensing unit, and a third image sensing unit. And a fourth image sensing unit, the indicating plane has a first side and a second side, the first side is opposite to the second side, the first image sensing unit and the second image The sensing unit is disposed on the first side of the first image sensing unit, and the third image sensing unit is disposed on the second side of the fourth image sensing unit. The first image sensing unit is coupled to the second image sensing unit. The second image sensing unit is opposite to the third image sensing unit, the first image sensing unit, the second image sensing unit, and the third image sensing unit are opposite to the fourth image sensing unit. A central touch area is defined between the fourth image sensing unit, and the method for calculating the touch point coordinates includes: when a touch gesture is performed on the central touch area, the first image sensing unit senses Detecting a first image, the second image sensing unit sensing a second image, the third image sensing unit sensing a third image, and the fourth image sensing unit sensing a fourth image; Calculating a first coordinate of a touch point according to the first image and the fourth image; calculating a second coordinate of the touch point according to the second image and the third image; and integrating the first coordinate by using a weight And the second coordinate to calculate the output coordinate of one of the touch points. The method of claim 6 requesting computing coordinates of the touch point of entry, wherein the output of the coordinates of the touch point is calculated by the following _{formula: X T = X 1 × W} + X 2 × (1- W); and Y _T = Y ₁ × W + Y ₂ × (1- W ); where (X _T , Y _T ) represents the output coordinate, and (X ₁ , Y ₁ ) represents the first coordinate, (X ₂ , Y ₂ ) Indicates the second coordinate, and W represents the weight. The method for calculating a touch point coordinate according to claim 7, wherein the connection between the first image sensing unit and the fourth image sensing unit is a first boundary of the central touch area, and the second image is The connection between the sensing unit and the third image sensing unit is a second boundary of the central touch area, wherein the first touch line defines a first critical line and a second critical line, the first critical line a threshold distance from the first boundary, the second critical line is spaced from the second boundary by the threshold distance, and when the touch point is between the first boundary and the first critical line, the weight is equal to 0; When the touch point is between the second boundary and the second critical line, the weight is equal to 1; when the touch point is between the first critical line and the second critical line, the weight is equal to , d represents the distance between the touch point and the first boundary, T represents the threshold distance, and D represents the distance between the first boundary and the second boundary. The method for calculating a touch point coordinate according to claim 6, further comprising: calculating N touch points according to the first image and the fourth image, and calculating M according to the second image and the third image a touch point, wherein N and M are both positive integers; determining whether N is greater than M; when N is greater than M, calculating and outputting coordinates of the N touch points; and when N is less than M, calculating and outputting the M The coordinates of the touch points. The method for calculating a touch point coordinate as described in claim 9, further comprising: when N is equal to M, pairing the N touch points with the M touch points to obtain N pairs of touch points; And integrating the coordinates of the N pairs of touch points with the weight to calculate N output coordinates of the N pairs of touch points.