Patent Publication Number: US-2016239149-A1

Title: Method of identifying touch gesture and touch system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of United States patent application filed on Mar. 17, 2014 and having application Ser. No. 14/215,415, the entire contents of which are hereby incorporated herein by reference 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method of identifying touch gesture, and more particularly to a method of identifying touch gesture and a touch system. 
     2. Description of the Related Art 
     Touch pads or external touch pads of notebook computers serve as an alternative to a physical mouse device, and is basically equipped with functions for controlling cursor, left button and right button on the computer systems. To keep abreast of software development of manufacturers of computer systems, such touch pads start providing a control function over edge swipe gesture. For example, when computer systems initialize a hidden menu function of a window environment and users are allowed to perform the control over cursor, left button and right button, the menu bar is initially in a hidden state. Once the touch pads detect that users&#39; gestures pertain to edge swipe gestures, the computer systems will automatically display the hidden menu bar on the screens for users to pick. Besides, functions of switching pages on screens can be supported in a similar fashion. 
     Microsoft® has already laid the groundwork for the rules of determining edge swipe gestures. However, due to low accuracy in determining the edge swipe gestures, the touch pads incorporating the determination rules are not handy in use. The reason is described as follows. 
     With reference to  FIGS. 19A and 19B , based on operational habits of users, a front left portion and a front right portion of a notebook computer with respect to users are usually designed as the left button and the right button. Pressing the front left portion and the front right portion can perform the functions of the left button and the right button. As to the control over edge swipe gestures, bordering portions adjacent to the left side, the right side, and the top side of the touch pad are defined for edge swipe gestures to occur. With reference to  FIG. 20 , a touch device  10  capable of determining edge swipe gestures is configured with a bordering area W and a touch object-moving distance R, and a method of determining edge swipe gestures is performed under a touch mode. With reference to  FIGS. 21A to 21D , when a finger moves inwards from outside the touch device  10  to firmly and sequentially touch a first sensing line to a third sensing line X 1 ˜X 3  of the touch device  10 , a first sensing signal to a third sensing signal S 1 ˜S 3  are sequentially outputted as shown in  FIG. 21E . The sensing values of the first sensing signal S 1  to the third sensing signal S 3  are greater than a sensing threshold dVth 1  as shown in  FIG. 21F . When the touch device  10  is determined by the touch mode for its sensing state, the first sensing line X 1  in the bordering area W can sense the finger thereon, the finger can be sensed to sequentially move from the first sensing line to the third sensing line X 1 ˜X 3  in an inward direction, and the finger is sensed to actually move a distance greater than the preset touch object-moving distance R in a period of time. Accordingly, the rules of determining edge swipe gestures are met, and the movement of the finger is determined as an edge swipe gesture. 
     With reference to  FIGS. 19A and 19B , the foregoing touch device  10  is combined with a case  20  of a notebook computer. If a top surface of the touch device  10  is not flush with a top surface of the case  20  and a finger swipes from the case  20  to the right side of the touch device  10  as shown in  FIGS. 20, 22A and 22B , the finger is not firmly pressing the sensing lines when the finger is on the first sensing line X 1  until the finger is on the second sensing line X 2  and the third sensing line X 3  as shown in  FIGS. 22C and 22D . With reference to  FIG. 22F , although the first sensing line X 1  outputs a first sensing signal S 1  having a non-zero sensing value, the sensing value of the first sensing signal S 1  is lower than the sensing threshold dVth 1  in the touch mode. As there is no touch object identified to be on the bordering area, the rules of determining edge swipe gestures are not satisfied and no edge swipe gesture can be identified. Similar situation takes place when an area of a finger touching the bordering area is small. Since the sensing value of the first sensing signal S 1  outputted from the first sensing line X 1  is lower than the sensing threshold dVth 1 , the finger&#39;s movement fails to be identified as an edge swipe gesture, and the hidden menu bar is unable to be displayed on the screen of a window environment. 
     SUMMARY OF THE INVENTION 
     In view of the technical shortcomings in the forgoing conventional method of identifying edge swipe gesture lacking sensitive identification of edge swipe gestures, the objective of the present invention is to provide a method of identifying edge touch gesture. 
     To achieve the foregoing objective, the method of identifying edge touch gesture is performed by a controller of a touch device, and has steps of: 
     a. scanning the touch device under a hover mode; 
     b. scanning the touch device under a touch mode; 
     c. determining if there is a touch object on the touch device according to a scanning result of the touch mode; and 
     d. when there is a touch object on the touch device, identifying the gesture according to a scanning result of the hover mode and the scanning result of the touch mode. 
     The foregoing method employs the hover mode and the touch mode to respectively acquire sensing signals on the edge area and the non-edge area of a touch pad. Each single sensing frame is generated by converting the sensing signals on the edge area and on the non-edge edge. As being sensitive to small sensing value, the hover mode is used to acutely sense a touch object, such as a finger or stylus, swiping through the edge area. When users swipe through the touch pad with the touch object from one edge of the touch pad, despite the failure of touching the edge area or small contact area with the edge area, users&#39; swiping movement can be identified by the hover mode. After the swiping distance and time are calculated and meet the requirements of edge swipe gesture, users&#39; edge swipe gesture can be correctly identified as an edge swipe gesture. 
     To achieve the foregoing objective, the method of opening window control bar through identification of edge swipe gesture is performed by a controller of a touch device, and has steps of: 
     acquiring at least one first sensing signal on an edge area of the touch device under a hover mode; 
     acquiring multiple second sensing signals on a non-edge area of the touch device under a touch mode; 
     determining if a valid touch of a touch object occurs on the non-edge area of the touch device according to the second sensing signals; 
     when the valid touch of the touch object occurs on the non-edge area, determining if a valid touch of the touch object occurs on the edge area of the touch device according to the at least one first sensing signal; 
     when the valid touch of the touch object occurs on the edge area, determining if a distance between the valid touches on the edge area and the non-edge area within a swipe time exceeds a swipe distance; and 
     when the distance exceeds the swipe distance, sending out a signal to an operating system for the operating system to open a corresponding control bar. 
     The foregoing method employs the hover mode and the touch mode to respectively acquire sensing signals on the edge area and the non-edge area of the touch device. Being sensitive to small sensing value, the hover mode is used to accurately sense a touch object, such as a finger or stylus, swiping through the edge area so as to identify the sensed movement as a valid touch. After the swiping distance and time are calculated and meet the requirements of edge swipe gesture, users&#39; edge swipe gesture can be correctly identified and a signal, such as a hot key signal, can then be sent to an operating system. The operating system will open a corresponding window control bar according to the signal to achieve a higher success rate for correctly opening a window control bar through the identification of edge swipe gesture. 
     To achieve the foregoing objective, another method of identifying edge swipe gesture is performed by a controller of a touch device, and has steps of: 
     acquiring at least one first sensing signal on an edge area of the touch device under a hover mode; 
     acquiring multiple second sensing signals on a non-edge area of the touch device under a touch mode; 
     determining if there is a touch object on the non-edge area according to the second sensing signals, and when there is a touch object on the non-edge area, determining if the touch object has previously appeared on the edge area according to the at least one first sensing signal; and 
     when the touch object has previously appeared on the edge area according to the at least one first sensing signal, sequentially outputting multiple sets of coordinates of the touch object on the edge area and on the non-edge area to an operating system for the operating system to identify a swipe gesture. 
     Similarly, the foregoing method also employs the hover mode and the touch mode to respectively acquire sensing signals on the edge area and the non-edge area of the touch device to increase the identification rate of users&#39; edge swipe gesture except when the touch device is used as a touch screen. After a swiping movement is identified, the coordinates of the object on the edge area and on the non-edge area are sequentially outputted to the operating system of the computer for the operating system to make final determination of edge swipe gesture. 
     To achieve the foregoing objective, a major technical approach is to provide a touch system for converting a user&#39;s operation command into a signal launching a window control bar through an operating system of a computer in the touch system, and the touch system has a computer, a touch device, a display and a controller. 
     The computer has an operating system installed thereon. 
     The touch device is electrically connected to the computer and has an edge area and a non-edge area. 
     The edge area extends inwards a distance from an edge of the touch device. 
     The display is electrically connected to the computer. 
     The controller is electrically connected to the touch device and the computer, generates a signal for launching a window control bar after a touch object hovers on the edge area of the touch device and then touches the non-edge area of the touch device, and outputs the signal to the computer for the operating system of the computer to display a window control bar on the display. 
     The controller of the foregoing touch system in collaboration with the touch device can fulfill the foregoing two methods of identifying edge swipe gesture and output a signal for launching window control bar to the computer after an edge swipe gesture is identified. The operating system of the computer then opens a window control bar on the display according to the signal. 
     Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic view of a first embodiment of a touch device applied to a touch pad in accordance with the present invention; 
         FIG. 1B  is a schematic view of a second embodiment of a touch device applied to a touch pad in accordance with the present invention; 
         FIG. 2  is a flow diagram of a first embodiment of a method of identifying edge swipe gesture performed on the touch device in  FIG. 1A ; 
         FIG. 3A  is a schematic view of a touch screen to which the touch devices in  FIGS. 1A and 1B  are applied; 
         FIG. 3B  is a functional block diagram of the touch screen in  FIG. 3A ; 
         FIG. 4A  is a schematic view of a first embodiment of a touch device with a touch screen in accordance with the present invention; 
         FIG. 4B  is a schematic view of a second embodiment of a touch device with a touch screen in accordance with the present invention; 
         FIG. 5  is a flow diagram of a second embodiment of a method of identifying edge swipe gesture performed on the touch screen of the touch device in  FIG. 4A ; 
         FIGS. 6A and 6B  are schematic views showing generation of an effective sensing frame in accordance with the present invention; 
         FIG. 7A  is a schematic diagram showing a process of a first signal processed on an edge area of a touch panel in accordance with the present invention; 
         FIG. 7B  is a schematic diagram showing a process of a first signal processed on a non-edge area of a touch panel in accordance with the present invention; 
         FIG. 8A  is a schematic diagram showing a process of a second signal processed on an edge area of a touch panel in accordance with the present invention; 
         FIG. 8B  is a schematic diagram showing a process of a second signal processed on a non-edge area of a touch device in accordance with the present invention; 
         FIG. 9  is a flow diagram of a third embodiment of a method of identifying edge swipe gesture performed on the touch device in  FIG. 1B ; 
         FIGS. 10A, 10B, 10C and 10D  are schematic views of finger movements associated with an edge swipe gesture on a touch device in accordance with the present invention; 
         FIGS. 11A, 11B and 11C  are waveform diagrams of sensing signals at corresponding finger locations in  FIGS. 10B, 10C and 10D ; 
         FIGS. 12A, 12B and 12C  are waveform diagrams of signal-processed sensing signals in  FIGS. 11A, 11B and 11C ; 
         FIGS. 13A, 13B, 13C and 13D  are schematic views of finger movements associated with an edge swipe gesture on a touch device in accordance with the present invention; 
         FIGS. 14A, 14B and 14C  are waveform diagrams of sensing signals at corresponding finger locations in  FIGS. 13B, 13C and 13D ; 
         FIGS. 15A, 15B and 15C  are waveform diagrams of signal-processed sensing signals in  FIGS. 14A, 14B and 14C ; 
         FIG. 16  is a flow diagram of a method of opening window control bar in accordance with the present invention; 
         FIG. 17  is a schematic diagram showing signal conversion after outputting a control signal to an operating system in accordance with the present invention; 
         FIG. 18  is a schematic view of opening a window control bar on a touch device in accordance with the present invention; 
         FIG. 19A  is a schematic view of a conventional touch pad mounted on a housing of a notebook computer; 
         FIG. 19B  is a partially enlarged operational schematic view of the conventional touch pad in  FIG. 19A ; 
         FIG. 20  is a schematic view of a conventional touch pad; 
         FIGS. 21A, 21B, 21C and 21D  are schematic views of finger movements associated with an edge swipe gesture on a conventional touch device; 
         FIGS. 21E and 21F  are waveform diagrams of sensing signals in  FIGS. 21A, 21B, 21C and 21D ; 
         FIGS. 22A, 22B, 22C and 22D  are schematic views of finger movements associated with an edge swipe gesture not touching an outmost sensing line of a conventional touch device; and 
         FIGS. 22E to 22F  are waveform diagrams of sensing signals in  FIGS. 22A, 22B, 22C and 22D . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention targets at increasing success rate of identifying swipe gesture on a touch device and can be also applied to open window control bar for users to increase a success rate in opening window control bar. The touch devices of the present invention are applicable to touch panels or touch screens. 
     With reference to  FIG. 1A , a first embodiment of a touch device  10  in accordance with the present invention has multiple sensing lines along a first axis X 1 ˜Xk, multiple sensing lines along a second axis Y 1 ˜Yq, and a controller  20  electrically connected to the sensing lines along the first axis and the second axis X 1 ˜Xk, Y 1 ˜Yq. The controller  20  drives the sensing lines along the first axis and the second axis X 1 ˜Xk, Y 1 ˜Yq by means of a self scan approach or a mutual scan approach, receives sensing signals of the sensing lines along the first axis and the second axis X 1 ˜Xk, Y 1 ˜Yq, and identifies if there is any effective touch or touch object on the touch device  10  according to the sensing signals. The touch device  10  has at least one edge area  11  and a non-edge area  12  defined on the touch device  10 . The edge area  11  is defined as an area extending a distance leftwards from a right edge of the touch device  10  or extending a distance rightwards from a left edge of the touch device  10 . When applied to a notebook computer, the touch device  10  further has an edge area extending a distance downwards from a top edge of the touch device  10 . Each of the at least one edge area  11  contains a single sensing line X 1 , Xk or Yq being parallel to a nearest edge of the touch device  10 . With reference to  FIG. 1B , the touch device  10 ′ has at least one edge area  11 , and each of the at least one edge area  11  contains two or more than two sensing lines X 1 /X 2 , Xk−1/Xk or Yq−1/Yq being parallel to a length direction of a corresponding edge area  11 . Preferably, the edge area  11  is the edge area specified by the “edge swipe gesture control functions” of WIN8™. The non-edge area  12  is defined as an area other than the at least one edge area  11  on the touch device  10 ,  10 ′. 
     With reference to  FIG. 2 , a first embodiment of a method of identifying edge swipe gesture in accordance with the present invention is performed by the controller  20  and has the following steps. 
     Step S 10 : Acquire a first sensing signal on the edge area  11  of the touch device  10  under a hover mode and acquire a second sensing signal on an entire area of the touch device  10  under a touch mode. 
     Step S 11 : Determine if there is a touch object on the non-edge area  12  according to the second sensing signal, if positive, perform step S 12 , and otherwise, resume step S 10 . 
     Step S 12 : Determine if the touch object has previously appeared on the edge area  11  according to the first sensing signal. In other words, determine if the first sensing signal has varied in response to the presence of the touch object on the edge area  11 . If the determination result of step S 12  is positive, perform step S 13 . Otherwise, resume step S 10 . 
     Step S 13 : Determine if a displacement of the touch object within a swipe time exceeds a swipe distance. In other words, determine if a distance between two positions of the touch object on the edge area  11  and on the non-edge area  12  exceeds the swipe distance within the swipe time. Preferably, the swipe time and the swiping distance meet the specifications of the “edge swipe gesture control functions” in WIN8™. If the determination result of step S 13  is positive, perform step S 14 . Otherwise, resume step S 10 . 
     Step S 14 : Generate a signal indicating that the movement of the touch object corresponds to an edge swipe gesture. 
     With reference to  FIG. 3A , a touch device  10   a  is a touch screen  1 . With reference to  FIG. 3B , the touch screen  1  has a display  2 . The touch device  10   a  is electrically connected to a controller  20 . The controller  20  is electrically connected to the display  2  of the touch screen  1  through a computer  3 . With reference to  FIG. 4A , the touch device  10   a  has multiple sensing lines along a first axis and a second axis X 1 ˜Xn, Y 1 ˜Ym and a controller electrically connected to the sensing lines along the first axis and the second axis X 1 ˜Xn, Y 1 ˜Ym. The controller  20  drives the sensing lines along the first axis and the second axis X 1 ˜Xn, Y 1 ˜Ym by means of a self scan approach or a mutual scan approach, receives sensing signals of the sensing lines along the first axis and the second axis X 1 ˜Xn, Y 1 ˜Ym, and identifies if there is any touch object on the touch device  10   a  according to the sensing signals. Each of the at least one edge area  11  contains a single sensing line X 1 , Xn, Y 1  or Ym being parallel to a nearest edge of the touch device  10 . With reference to  FIG. 4B , the touch device  10   a ′ has at least one edge area  11 , and each of the at least one edge area  11  contains two or more than two sensing lines X 1 /X 2 , Xn−1/Xn or Y 1 /Y 2  being parallel to a length direction of a corresponding edge area  11 . 
     With reference to  FIG. 5 , a second embodiment of a method of identifying edge swipe gesture in accordance with the present invention is performed by the controller  20  and has the following steps. 
     Step S 20 : Acquire at least one first sensing signal on the edge area  11  of the touch device  10   a  under a hover mode and acquire multiple second sensing signals on an entire area  12  of the touch device  10   a  under a touch mode. 
     Step S 21 : Determine if there is a touch object on the non-edge area  12  of the touch device  10   a  according to the second sensing signals, if positive, perform step S 22 , and otherwise, resume step S 20 . 
     Step S 22 : Determine if the touch object has previously appeared on the edge area  11  according to the first sensing signal. In other words, determine if any touch object was present on the edge area  11  according to the first sensing signal. If the determination result of step S 22  is positive, perform step S 23 . Otherwise, resume step S 20 . 
     Step S 23 : Sequentially output multiple sets of coordinates of the touch object on the edge area  11  and on the non-edge area  12  to the operating system (OS) of the computer  3  for the OS to identify a swipe gesture. 
     Moreover, to increase the accuracy of the OS in identifying a swipe gesture, the controller  20  can further perform a step S 221  after step S 22  to set up a preset time that is not greater than the swipe time and a preset distance that is not greater than the swipe distance. When determining the touch object has appeared on both the edge area  11  and the non-edge area  12  in step S 21 , the controller  20  further determines if a displacement of the touch object moving from the edge area  11  to the non-edge area  12  within the preset time is within the preset distance. If the determination result is positive, it indicates that a swipe gesture may be identified, and the controller  20  further performs step S 22 . If the determination result is negative, the controller  20  only outputs the current set of coordinates of the touch object on the non-edge area  12  to the computer  3 . To determine whether the displacement is within the preset distance, the controller  20  takes the first set of coordinates of the touch object on the non-edge area  12  and the any set of coordinates of the touch object or the last set of coordinates of the touch object on the edge area  11  to calculate the displacement, and compares the displacement with the preset distance to determine if the displacement is within the preset distance in step S 221 . Step S 221  aims to eliminate the gesture using two fingers to respectively tap the edge area  11  and the non-edge area  12  in a sequential manner to enhance the accuracy in identifying a swipe gesture. Step  23  serves to sequentially output the coordinates of the touch object according to the time sequence when the touch object moves from the edge area  11  to the non-edge area  12 . As sequentially receiving the coordinates of the touch object when the touch object moves from the edge area  11  to the non-edge area  12 , the OS of the computer  3  can determine if the displacement of the touch object moving from the edge area  11  to the non-edge area  12  within the swipe time has exceeded a swipe distance within a swipe time, in which the swipe time and the swipe distance are specified in the “edge swipe gesture control functions” in WIN8™. If the displacement has exceeded the swipe distance within the swipe time, it indicates that current user&#39;s gesture is a swipe gesture. 
     To sum up, when users&#39; swipe movement approaches the edge area  11 , instead of immediately receiving the coordinates of the touch object on the edge area  11  transmitted from the controller  20 , the OS of the computer  3  receives coordinates of the touch object on the edge area  11  only after the controller  20  identifies the presence of the object on the non-edge area  12 , thereby effectively enhancing the correctness of the computer in identifying swipe gesture. As the involved processing time is rather short, users will not actually feel the time delay arising from the processing. 
     With reference to  FIGS. 1A, 4A, 6A and 6B , the controller  20  of the touch device  10 ,  10 ′ scans the sensing lines along the first axis and the second axis X 1 ˜Xn, Y 1 ˜Ym using a scan cycle Ts to sequentially generate sensing frames F 1 ˜F 4 . The controller  20  may process sensing signals under a hover mode and a touch mode. With reference to  FIG. 6B , the sensing frame F 1  is obtained by processing the sensing signals over the entire area of the touch device  10 ,  10 ′ under the touch mode, and the sensing frame F 2  is obtained by processing the sensing signals over the edge area  11  of the touch device  10 ,  10 ′ under the hover mode. The following description explains how to implement the different hover mode and touch mode. 
     With reference to  FIGS. 7A and 7B , a first implementation of the touch mode and the hover mode is shown. During a step of reading the first sensing signal on the edge area  11  of the touch device  10 ,  10 ′ under the hover mode, the controller  20  reads the sensing signals on the edge area  11  of the touch device  10 ,  10 ′ detected within each scan cycle Ts as illustrated in  1 A and  3 A to read the sensing signal S 1  of the rightmost sensing line X 1 . With further reference to  FIG. 7A , each sensing signal S 1  of the sensing line X 1  on the edge area  11  is multiplied by a hover sensitivity parameter G 2 . Each sensing signal after the multiplication is converted by a digital conversion into the first sensing signal S 1 ′ in generation of the sensing frames F 2 , F 4  in  FIG. 6B . 
     As to the step of reading the second sensing signal over the entire area of the touch device  10 ,  10 ′ under the touch mode, with reference to  FIG. 7B , the controller  20  reads the sensing signals on the entire area of the touch device  10 ,  10 ′ detected within each scan cycle Ts, multiplies each sensing signal S 3  by a touch sensitivity parameter G 1 , converts the sensing signal after the multiplication with an analog-to-digital conversion (ADC), and filters the sensing signal after the ADC through a digital filter, such as IIR (Infinite Impulse Response) filter. The controller  20  further computes a standard deviation or a mean by referring to previous one or previous few sensing frames with the entire area of the touch device scanned, so as to obtain the second sensing signal S 3 ′. As the hover sensitivity parameter is greater than the touch sensitivity parameter (G 2 &gt;G 1 ), the sensing signals on the edge area  11  are amplified. 
     When swiping through one edge of the touch device  10 ,  10 ′, a user&#39;s finger is able to approach but fails to touch the sensing line X 1  on the edge area  11  due to the height difference at the edge of the touch device  10 ,  10 ′. Hence, the sensing signal sensed at the sensing line X 1  is relatively weaker and is lower than a touch sensing threshold dVth 1 . However, after the signal processing step as shown in  FIG. 7A  under the hover mode, the sensing signal S 1  is amplified with gain enhancement to become the first sensing signal S 1 ′. Therefore, during the step of determining if the touch object has appeared on the edge area by means of the first sensing signal S 1 ′, the first sensing signal S 1 ′ sensed within the edge area  11  can be directly determined if it is greater than the touch sensing threshold dVth 1 . If the first sensing signal S 1 ′ is greater than the touch sensing threshold dVth 1 , the touch object is identified to have appeared within the edge area  11 . As to the touch object identification on the non-edge area  12 , the second sensing signal S 3 ′ is similarly compared with the touch sensing threshold dVth 1 . If the second sensing signal S 3 ′ is also greater than the touch sensing threshold dVth 1 , the touch object is identified to be present on the touch device. 
     With reference to  FIGS. 8A and 8B , a second implementation of the touch mode and the hover mode is shown. During the step of reading the first sensing signal S 1 ″ on the edge area  11  of the touch device  10 ,  10 ′ under the hover mode, the sensing signal S 1  read on the sensing line X 1  of the edge area  11  is multiplied by a sensitivity parameter G. The sensing signal after the multiplication is converted into the first sensing signal S 1 ″ by an analog-to-digital conversion. Each sensing signal on the non-edge area of the touch device  10 ,  10 ′ sensed under the touch mode is also multiplied by the sensitivity parameter G. The sensing signal after the multiplication is converted by an analog-to-digital conversion (ADC). The sensing signal after the ADC is filtered by a digital filter, such as an IIR filter. The controller  20  further computes a standard deviation or a mean by referring to previous one or previous few sensing frames with the entire area of the touch device scanned, so as to obtain the second sensing signal S 3 ′. It is noted from  FIGS. 8A and 8B  that the sensing values of the sensing signals filtered by the digital filter slightly drop. To successfully identify the weaker first sensing signal S 1 ″, the controller  20  in  FIGS. 1A and 3A  will set up a first sensing threshold (same as the touch sensing threshold dVth 1 ) and a second sensing threshold (dVth 2 ). The second sensing threshold is less than the first sensing threshold (dVth 2 &lt;dVth 1 ). As long as the first sensing signal S 1 ″ is greater than the second sensing threshold, the first sensing signal S 1 ″ can still be considered to be valid. 
     With reference to  FIG. 9 , a third embodiment of a method of identifying edge swipe gesture in accordance with the present invention is substantially the same as the method illustrated in  FIG. 2 , and adopts a first implementation of combining the touch mode and the hover mode as illustrated in  FIGS. 10D, 11C and 12C . When the sensing signal S 3 ′ on the non-edge area of the touch device has been signal-processed and is determined that its sensing value has exceeded the touch sensing threshold dVth 1 , the controller  20  identifies the touch object present on the non-edge area of the touch device and further determines if the touch object is present on the edge area according to previous two sensing frames. The present embodiment is performed on the touch device in  FIG. 1B . Hence, a step S 121  of determining if the touch object moves from the edge area  11  to the non-edge area  12  is additionally included in the step S 12 . In other words, the moving direction of the touch object is determined by the variations of the first sensing signals S 1 ′, S 2 ′ on the two sensing lines X 1 , X 2  on the edge area  11  according to the previously-generated first sensing frame and second sensing frame. Specifically, the finger-moving direction is illustrated in  FIGS. 10A to 10D . With reference to  FIGS. 10B and 10C , when the finger swipes through but does not touch the edge area  11 , the sensing signals of the sensing lines X 1 , X 2  are illustrated in  FIGS. 11A and 11B . Before undergoing the gain-enhancing signal processing, both sensing values of the sensing signals S 1  of the sensing line X 1  in the consecutive two scanning results do not exceed the touch sensing threshold dVth 1 . Both the sensing values of the first sensing signals S 1  and the second sensing signal S 2  on the sensing lines X 1 , X 2  in the consecutive first and second sensing frames, which are illustrated in  FIGS. 12A and 12B  and generated after the gain-enhancing signal processing, exceed the touch sensing threshold dVth 1 . Subsequently, the moving direction of the touch object is to be determined. As the sensing value of the first sensing signal S 1 ′ on the sensing line X 1  is greater than the sensing value of the first sensing signal S 2 ′ on the sensing line X 2  as illustrated in  FIG. 12A  in the first sensing frame and the sensing value of the first sensing signal S 1 ′ on the sensing line X 1  is less than the sensing value of the first sensing signal S 2 ′ on the sensing line X 2  as illustrated in  FIG. 12B  in the second sensing frame, the touch object is determined to move from the edge area  11  to the non-edge area  12 . 
     An second implementation of combining the touch mode and the hover mode can be employed to determine if any touch object is present on the edge area. Similarly, as illustrated in  FIGS. 13D, 14C and 15C , determining if a touch object is present on the edge area of the touch device takes place after determining that the touch object is identified on the non-edge area according to the sensing signal S 3 ″. With reference to  FIGS. 13B and 13C , when a finger swipes through but does not touch the edge area  11  due to the height difference at the edge of the touch device, the sensing signals of the sensing lines X 1 , X 2  are illustrated as in  FIGS. 14A and 14B . In the consecutive first and second sensing frames generated after the signal processing in the hover mode as illustrated in  FIGS. 15A and 15B , although not being greater than the first sensing threshold dVth 1 , the sensing values of the first sensing signals S 1 ″, S 2 ″ already exceed the second sensing threshold dVth 2 . Subsequently, the moving direction of the touch object is to be determined. As the sensing value of the first sensing signal S 1 ″ on the sensing line X 1  is greater than the sensing value of the first sensing signal S 2 ″ on the sensing line X 2  as illustrated in  FIG. 15A  in the first sensing frame and the sensing value of the first sensing signal S 1 ″ on the sensing line X 1  is less than the sensing value of the first sensing signal S 2 ″ on the sensing line X 2  as illustrated in  FIG. 15B  in the second sensing frame, the touch object is determined to move from the edge area  11  to the non-edge area  12 . 
     The edge area on the touch device  10   a ′ applied to the touch screen  1  in  FIG. 4B  has two or more than two sensing lines. Hence, step S 121  in  FIG. 9  can be added between steps S 22  and S 221  in  FIG. 5  to determine if the touch object moves from the edge area to the non-edge area, and step S 221  is performed only after the determination result in step  121  is positive. 
     The foregoing methods of identifying edge swipe gesture employ the hover mode and the touch mode to perform signal processing on the sensing signals on the edge area  11  and the non-edge area  12  of the touch device  10 ,  10 ′ so as to facilitate swipe gesture determination and increase the success rate in identifying edge swipe gesture by means of touch information detected under the hover mode. Such technique is also applicable to a method of opening window control bar. With reference to  FIG. 16 , the method of opening window control bar has the following steps. 
     Step S 30 : Acquire a first sensing signal on an edge area  11  of the touch device  10 ,  10 ′ under a hover mode and acquire a second sensing signal on an entire area of the touch device  10 ,  10 ′ under a touch mode. 
     Step S 31 : Determine if any valid touch occurs on the non-edge area  12  of the touch device  10 ,  10 ′ according to the second sensing signal. If the determination result is positive, perform step S 32 . Otherwise, resume step S 30 . 
     Step S 32 : Determine if any valid touch occurs on the edge area  11  of the touch device  10 ,  10 ′ according to the first sensing signal. If the determination result is positive, perform step S 33 . Otherwise, resume step S 30 . 
     Step S 33 : Determine if a calculated distance between the valid touches on the edge area  11  and the non-edge area  12  within a swipe time exceeds a swipe distance. If the determination result is positive, perform step S 34 . Otherwise, resume step S 30 . In a preferred implementation of the step  33 , a distance between an initial position of one of the valid touches on the edge area and a last position of another valid touch on the touch device is calculated, and the distance is determined if exceeding the swipe distance. 
     Step S 34 : Send out a hot key signal. The hot key signal is sent to an OS for the OS to open a corresponding window control bar. Additionally, a step of determining the valid touch moves from the edge area  11  to the non-edge area  12  can be added. 
     To fulfill the foregoing steps, with reference to  FIG. 17 , the controller  20  of the touch device  10 ,  10 ′ performs steps S 20 -S 23  in a kernel layer therein, and outputs the coordinates (X, Y) of the valid touches to an application program operated on the highest application layer (user interface) for the application program to determine if an edge swipe gesture is identified according to the coordinates of the valid touches. When an edge swipe gesture is identified, the controller  20  generates a hot key signal corresponding to the edge swipe gesture and sends the hot key signal to the user interface of WIN8™. After receiving the hot key signal, a computer with WIN8™ installed thereon performs a function corresponding to the hot key signal. An example is illustrated in  FIG. 18 . When users make a left swipe from the right edge of the touch panel, once the swipe movement is successfully identified, the controller  20  of the touch device  10 ,  10 ′ in  FIG. 1A or 1B  outputs a signal to an application. After identifying the swipe movement as an edge swipe gesture, the application outputs a hot key signal specified by WIN8™, which is equivalent to the hot key signal generated by simultaneously pressing the “WINDOWS” key and the “C” key on a standard keyboard, for the OS to receive the hot key signal. The computer then controls to display a window control bar  31  on a right edge of a screen  30  of a display. If the application identifies that the swipe movement is an edge swipe gesture moving from left to right so as to open the window control bar  31  on a left edge of the screen  30 , the application then outputs a hot key signal specified by WIN8™ which is equivalent to the hot key signal generated by simultaneously pressing the “WINDOWS” key and the “Tab” key on a standard keyboard. If the application identifies that the swipe movement is an edge swipe gesture moving from top to bottom so as to open the window control bar  31  on a top edge of the screen  30 , the application then outputs a hot key signal specified by WIN8™ which is equivalent to the hot key signal generated by simultaneously pressing the “WINDOWS” key and the “Z” key on a standard keyboard. The foregoing description includes, but is not limited to, a feasible approach of identifying edge swipe gesture and opening window control bar. 
     In sum, the present invention respectively reads the sensing signals on the edge area and on the non-edge area of the touch device using the hover mode and the touch mode, determines if the signal-processed first sensing signal has varied after determining that a valid touch occurs on the non-edge area, and determines that a valid touch has already occurred on the edge area before the valid touch occurring on the non-edge area if the first sensing signal has varied so as to identify an edge swipe gesture. As the hover mode can sense weak sensing value of the sensing signals, using the hover mode in the present invention can sense the finger or stylus swiping through the edge area with higher degree of dexterity so as to easily identify a valid touch. Once the calculations of the swipe distance and swipe time meet the requirements of an edge swipe gesture, the present invention can correctly identify users&#39; swiping movement and send a hot key signal to an OS for the OS to open a corresponding control bar, thereby increasing the success rate in identifying edge swipe gesture and opening a control bar. 
     Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.