Patent Publication Number: US-2019192915-A1

Title: Treadmill and control method for controlling the treadmill belt thereof

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
     This application is a divisional application of U.S. application Ser. No. 15/418,621, filed Jan. 27, 2017, entitled “TREADMILL AND CONTROL METHOD FOR CONTROLLING THE TREADMILL BELT THEREOF”. The entire content of the above identified application is incorporated herein by reference. 
     Some references, which may include patents, patent applications and various publications, are cited and discussed in the description of this disclosure. The citation and/or discussion of such references is provided merely to clarify the description of the present disclosure and is not an admission that any such reference is “prior art” to the disclosure described herein. All references cited and discussed in this specification are incorporated herein by reference in their entireties and to the same extent as if each reference was individually incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to a treadmill and a control method for controlling the treadmill belt thereof; more particularly, to a treadmill and a control method for controlling the treadmill belt thereof in which an image sensor is utilized to measure specific light patterns or to determine the characteristics of the images of a user so as to adjust the treadmill belt accordingly. 
     2. Description of Related Art 
     Fitness has become an important issue for people all around the world, motivating more and more people to build an exercise habit. The treadmill is one of the most common exercise machines at present. A treadmill of the prior art provides functionalities such as speed adjustment, a timer, and various exercise modes so that users can adjust their exercise routine on the treadmill as needed. 
     In the prior art, when a user wishes to adjust the speed of the treadmill belt, manual operation of the control panel on the treadmill is required. However, since the user&#39;s physical strength will gradually decrease as the exercise continues, accidents may happen when the user tries but fails to reach the control panel from the farther end of the treadmill belt due to fatigue. 
     Furthermore, everyone has their own natural way of running. For example, some treadmill users habitually run towards a lateral side of the treadmill belt, which applies uneven pressure to the treadmill and hence is likely to shorten the lifespan of the treadmill after long-term use. 
     Therefore, one of the primary objectives in the art is to overcome the afore-mentioned shortcomings and provide a durable and safe treadmill. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present disclosure provides a treadmill that includes a treadmill belt, a first signal member, a first sensor, and a controller. The first signal member is disposed at position near a first side of the treadmill belt. The first sensor retrieves a first image. The first image includes a first light pattern provided by the first signal member, and the first light pattern extends from a first starting point of the first image. The controller is coupled to the first sensor and adjusts an operating speed of the treadmill belt in accordance with a characteristic property of the first light pattern. 
     Another embodiment of the present disclosure provides a control method for controlling the treadmill belt of a treadmill, in which the treadmill includes a treadmill belt. A first signal member is disposed at a position near a first side of the treadmill belt. The control method includes a step A: retrieving a first image using a first sensor, wherein the first image includes a first light pattern provided by the first signal member, the first light pattern extending from a first starting point of the first image; a step B: controlling an operating speed of the treadmill belt according to a length of the first light pattern using a controller. 
     According to another embodiment of the present disclosure, a treadmill is disclosed, in which the treadmill includes a treadmill belt, an image sensor, and a controller. The image sensor includes an image sensing unit for retrieving an image of a user. The controller is electrically connected to the image sensor and adjusts an operating speed of the treadmill belt according to the percentage of the pixels representing the user in all the pixels of the image. 
     Another embodiment of the present disclosure provides a control method for controlling the treadmill belt of a treadmill, in which the treadmill includes a treadmill belt, an image sensor, and a controller. The control method includes: an image sensing unit of the image sensor retrieving an image of a user, and the controller adjusting an operating speed according to the percentage of the pixels representing the user in all the pixels of the image. 
     Another embodiment of the present disclosure provides a treadmill including a treadmill belt, an image sensor including an image sensing unit for retrieving an image of a user, and a controller electrically connected to the image sensor, in which the controller performs at least one of a startup operation, a shutdown operation, a speed-up operation, and a slow-down operation according to at least one gesture image corresponding to at least one gesture made by the user. 
     The treadmill and the control method for controlling the treadmill belt thereof provided by the present disclosure can accelerate or decelerate the operating speed or stop the operation of the treadmill belt according to the physical condition and the running rate of the treadmill user according to the position of the treadmill user, preventing accidents that may occur when the user is too exhausted to keep up with the speed of the treadmill. Furthermore, the treadmill of the present disclosure can adjust the slope of the running surface such that the user can stay running in the middle of the treadmill belt, improving the user&#39;s running posture and reducing uneven pressure distribution applied to the treadmill. Moreover, the treadmill of the present disclosure can adjust the operating speed of the treadmill belt in accordance with the percentage of the pixels representing the user in the image retrieved by the image sensor, and can perform various operations in accordance with gestures made by the user shown in the image retrieved by the image sensor. Through the above technical means, the treadmill of the present disclosure performs operations and adjusts the treadmill belt automatically so that the treadmill users do not need to manually operate the treadmill. 
     In order to further the understanding of the present disclosure, the following embodiments are provided along with illustrations to facilitate the disclosure of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic diagram illustrating a treadmill according to one embodiment of the present disclosure. 
         FIG. 1B  is a schematic diagram illustrating a first sensor according to one embodiment of the present disclosure. 
         FIG. 2  is a schematic diagram illustrating the sensing areas on the treadmill belt of the treadmill according to one embodiment of the present disclosure. 
         FIG. 3  is a schematic diagram of a first image according to one embodiment of the present disclosure. 
         FIGS. 4A and 4B  are two first images with different parts thereof being covered. 
         FIG. 5  is a schematic diagram illustrating the sensing areas on the treadmill belt of the treadmill according to one embodiment of the present disclosure. 
         FIGS. 6A to 6C  are the first images with different parts thereof being covered. 
         FIG. 7  is a schematic diagram illustrating the sensing areas on the treadmill belt of the treadmill according to one embodiment of the present disclosure. 
         FIGS. 8A and 8B  respectively show a first image and a second image according to one embodiment of the present disclosure. 
         FIGS. 9A and 9B  respectively show the first image and the second image retrieved when an object is in a first detection area. 
         FIGS. 10A and 10B  respectively show the first image and the second image retrieved when an object is in a second detection area. 
         FIG. 11  is a flow chart illustrating a control method for controlling the treadmill belt of a treadmill according to one embodiment of the present disclosure. 
         FIG. 12  is a flow chart illustrating the control method for controlling the treadmill belt of a treadmill according to another embodiment of the present disclosure. 
         FIG. 13  is a flow chart illustrating the control method for controlling the treadmill belt of a treadmill according to yet another embodiment of the present disclosure. 
         FIG. 14A  is a flow chart illustrating the treadmill according to one embodiment of the present disclosure. 
         FIG. 14B  is a schematic diagram illustrating an image sensor according to one embodiment of the present disclosure. 
         FIGS. 15A, 15B, and 15C  show the images retrieved by the image sensing units according to one embodiment of the present disclosure. 
         FIG. 16  is a flow chart illustrating a control method for controlling the treadmill belt of a treadmill according to another embodiment of the present disclosure. 
         FIG. 17  is a flow chart illustrating a control method for controlling the treadmill belt of a treadmill according to yet another embodiment of the present disclosure. 
         FIG. 18  is a flow chart illustrating a control method for controlling the treadmill belt of a treadmill according to another embodiment of the present disclosure. 
         FIG. 19  is a schematic view illustrating the detection areas on the treadmill belt of a treadmill according to one embodiment of the present disclosure. 
         FIGS. 20A and 20B  show the images retrieved by the image sensing units according to another embodiment of the present disclosure. 
         FIG. 21  is a flow chart illustrating the control method for controlling the treadmill belt of the treadmill according to another embodiment of the present disclosure. 
         FIG. 22  is a schematic diagram illustrating the treadmill according to another embodiment of the present disclosure. 
         FIG. 23  is a schematic diagram illustrating an image retrieved by the image sensing unit according to another embodiment of the present disclosure. 
         FIG. 24  is a table showing gestures and the commands corresponding thereto according to one embodiment of the present disclosure. 
         FIG. 25  is a flow chart illustrating the control method for controlling the treadmill belt of a treadmill according to another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The aforementioned illustrations and following detailed description are exemplary for the purpose of further explaining the scope of the present disclosure. Other objectives and advantages related to the present disclosure will be illustrated in the following description and appended drawings. 
     It should be understood that, although terms such as “first” and “second” are used to describe the components of the present disclosure in the description below, the components are not limited by these terms. Instead, the use of these terms is merely for the purpose of distinguishing components from each other. On the other hands, the term “or” may indicate that any one of the listed items or all the possible combinations thereof are included. 
     The present disclosure adjusts the operating speed of the treadmill belt of a treadmill by retrieving and measuring light patterns or the images of the treadmill users. 
     With reference to  FIG. 1A , the present disclosure provides a treadmill M including a treadmill belt  20 , a first signal member, a first sensor  51  and a controller  30 . The first signal member is disposed at position near a first side  204  of the treadmill belt  20 . The controller  30  is coupled to the first sensor  51 . Specifically, the treadmill M further includes a frame body  10  and a control panel  103  disposed on the frame body  10 . The controller  30  is disposed in the control panel  103  and provides the user with information such as the running rate, running time or warnings. The controller  30  can directly adjust the treadmill belt  20  based on the above information. The frame body  10  includes a first support rail  101  and a second support rail  102  that are disposed on both sides of the treadmill belt  20  at an end thereof. The first support rail  101  and the second support rail  102  extend upwardly. The first sensor  51  is disposed on the first support rail  101 . It should be noted that the position where the first sensor  51  is disposed enables the first sensor  51  to retrieve the first light pattern provided by the first signal member, in which the first sensor  51  can retrieve the whole or a part of the first light pattern. For example, the first sensor  51  can retrieve three fourths or a half of the first light pattern; however, the present disclosure is not limited thereto. Furthermore, the treadmill belt  20  includes a walking belt  202  and a support base  203  that supports the walking belt  202 . 
     The first signal member is used for providing light patterns. The first signal member can emit light so as to generate light patterns. Under such case the first sensor  51  can perform the detection of light patterns more effectively. The first signal member can be made of materials with high reflection coefficients which reflect light so as to provide the first sensor  51  with light patterns. 
     Specifically, the first signal member can be a light emitting component, such as infrared emitter, lase emitter, or LED. The first signal member can also be a reflective component with high reflection coefficient, such as a reflective belt or a retro reflector. The first signal member can also be formed of fluorescence glass balls, or include both a reflective belt and fluorescence glass balls. However, the present disclosure is not limited thereto. A person skilled in the art can choose the material of the first signal member according to actual needs. In the embodiments described below, the signal members are exemplified as reflective components, and the first signal member is a reflective component  41 . 
     The first sensor  51  is used for retrieving a first image that includes the first light pattern. Referring to  FIG. 3 , the first image  61  includes the first light pattern  611  provided by the first reflective component  41 . The first light pattern  611  extends from the first starting point S 1  of the first image  61 . The image output an image information representing the original image, without outputting the original image so that the transmission load between the image sensor and external processor can be reduced. It should be noted that the present disclosure uses the term “image” to represent the original image and/or the image information of the original image. 
     Referring to  FIG. 1A , the first sensor  51  is a complementary metal-oxide-semiconductor (CMOS) or a charge-coupled device (CCD), to which the present disclosure is not limited. 
     With reference to  FIG. 1B  and  FIG. 3 , the first sensor  51  can further include a first light emitter  71  that is disposed on the first sensor  51 . The first light emitter  71  generates a light beam that illuminates the first reflective component  41  to further generate a first light pattern  611 , thereby increasing the definition of the first light pattern  611  in the first image  61 . The first light emitter  71  can be an LED that emits infrared light or light with a wavelength greater than 850 nm. It should be noted that the first light emitter  71  can be exemplified in different ways, and the present disclosure is not limited to the above examples. 
     In addition, in the present embodiment, the treadmill M includes a sensor and a reflective component; however, the present disclosure is not limited thereto. In other embodiments, the treadmill M can include a plurality of sensors and reflective components, in which the plurality of reflective components are disposed at lateral sides of the treadmill belt  20  and the sensors can retrieve light patterns provided by at least one of the reflective components. In the embodiments described below, the treadmill M includes one sensor and one reflective component. 
     In the present embodiment, the first sensor  51  outputs the first image  61  to the controller  30 , which calculates the characteristic properties of the first light pattern  611  according to the first image  61 . In other embodiments, the first sensor  51  can also include a first image-processing device (not shown in  FIG. 1A ). The first image-processing device receives the first image  61  and calculates the characteristic properties of the first light pattern  611  according to the first image  61 . The first image-processing device then provides the controller  30  with the characteristic properties of the first light pattern  611 , with which the controller  30  adjusts the treadmill belt  20  accordingly. 
     When a user is running on the treadmill M, the user&#39;s body will cover part of the first image  61  retrieved by the first sensor  51  and change the characteristic properties of the first light pattern  611 . The characteristic properties of the first light pattern  611  can include the position and the length of the first light pattern  611 , and the number of segments included in the first light pattern  611 . Taking the length of the first light pattern  611  for example, when the user is running on the treadmill M, his/her feet will cover different parts of the first light pattern  611  such that the length of the first light pattern  611  changes while the user is running. More specifically, when the runner shifts towards the front end  201  of the treadmill belt  20 , the first light pattern  611  becomes shorter; when the runner shifts towards the rear end of the treadmill belt  20 , the first light pattern  611  becomes longer. 
     Through the above means, the relative position between the user and the front end  201  can be determined according to the length of the first light pattern  611 . Furthermore, the step frequency can be determined based on the variation frequency of the length of the first light pattern  611 . The step frequency can be a reference for the analysis of the user&#39;s exercise performance. 
     The controller  30  before calculates the length of the first light pattern  611  can define the first light pattern  611  based on the difference in brightness between the first light pattern  611  and the rest of the first image  61  (background image), and then the controller  30  calculate the length of the first light pattern  611  by determining the distance that the first light pattern  611  extends from the first starting point S 1 . The length of the first light pattern  611  may also be determined by the distance that the first light pattern  611  extends in a predetermined direction P, or the furthest distance the first light pattern  611  extends from the first starting point S 1 . In the present embodiment, the predetermined direction P refers to the direction in which the first light pattern  611  extends from the first starting point S 1  to an end point F 1 . 
     Moreover, in the embodiment that the positions of the first sensor  51  and the first signal member are fixed, the length of the first light pattern  611  can be determined based on where the first light pattern  611  is located on the first image  61 . For example, when the first light pattern  611  is in a first region of the first image  61 , the representative length of the first light pattern  611  is X 1 , and when the first light pattern  611  is located at both the first region and a second region, the representative length of the first light pattern  611  is X 2 , in which X 2  is longer than X  1 . Through the above means, the length of the first light pattern  611  can be determined and be referred to by the controller  30  when adjusting the operating speed of the treadmill belt  20 . 
     With reference to  FIG. 1A , the controller  30  adjusts the operating speed of the treadmill belt  20  according to at least one light pattern, e.g. the first light pattern  611 . In this embodiment, the controller  30  receives the first image  61  and calculates the length of the first light pattern  611  according to the first image  61 , and then adjusts the operating speed of the treadmill belt  20  accordingly. The technical aspects concerning the controller  30  is common knowledge in the art and thus will not be further explained herein. 
     Referring to  FIG. 1A  and  FIG. 3 , after a user presses the start button (not shown) on the treadmill M, the first sensor  51  retrieves the first image  61  after every specific time interval. The first image  61  contains the first light pattern  611  caused by light reflected from the first reflective component  41  to the first sensor  51 . When there is no object A standing on the treadmill M, the light reflected by the first reflective component  41  will not be blocked, which corresponds to the first light pattern  611  in  FIG. 3  that has a length being the distance between the first starting point S 1  and the end point F  1 . 
     Referring to  FIG. 2 , the treadmill M is divided into the first sensing area SR 1  adjacent to the first sensor  51  and the second sensing area SR 2  adjacent to the first sensing area SR 1 . The controller  30  determines whether the object A is in the first sensing area SR 1  or the second sensing area SR 2  according to the length of the first light pattern  611 , and then adjusts the operating speed of the treadmill belt  20  accordingly. In practice, the treadmill belt  20  is divided into a front region (corresponding to the first sensing area SR 1 ) and a rear region (corresponding to the second sensing area SR 2 ) in this embodiment. The length of the first light pattern  611  when the first light pattern  611  is covered by the object A is used for determining at which region the object A is located. 
     With reference to  FIGS. 4A and 4B , when the object A is on the treadmill belt  20  of the treadmill M, the object A will be situated between the first sensor  51  and the first reflective component  41  and thus will block the light transmitted therebetween, rendering the first light pattern  611  shown in  FIG. 4A  or  FIG. 4B . 
     Referring to  FIG. 4A , when the length of the first light pattern  611  that extends from the first starting point S 1  is smaller than a predetermined value TH 1 , the controller  30  determines that the object A is in the first sensing area SR 1  of the treadmill belt  20  and increases the operating speed of the treadmill belt  20  accordingly. Specifically, the controller  30  determines that the object A is moving faster than the treadmill belt  20  operates, and then increases the operating speed of the treadmill belt  20  such that the treadmill belt  20  is moving at the same rate as the object A so that the object A can stay moving in the middle of the treadmill belt  20 . In this embodiment, the first predetermined value TH 1  is a half of the distance between the first starting point S 1  and the end point F 1 . It should be noted that the value of the first predetermined value TH 1  is not limited to the above example. A person skilled in the art can set the threshold value according to actual needs. 
     With reference to  FIG. 4B , when the distance that the first light pattern  611  extends from the first starting point S 1  is greater than the first predetermined value TH 1 , the controller  30  determines that the object A is in the second sensing area SR 2  of the treadmill belt  20  and decreases the operating speed of the treadmill belt  20  accordingly. More specifically, the controller  30  determines that the object A is moving slower than the treadmill belt  20  operates, and then decreases the operating speed of the treadmill belt  20  such that the treadmill belt  20  is moving at the same rate as the object A so that the object A can stay moving in the middle of the treadmill belt  20 . 
     The control method for controlling the treadmill belt of the treadmill M will be explained below. With reference to  FIGS. 2, 4A, 4B and 11 , in step S 101 , the first sensor  51  retrieves the first image  61  after every specific time interval. The first image  61  includes the first light pattern  611  provided by the first reflective component  41  and extending from the first starting point S 1 . 
     In step S 102 , the controller  30  receives the first image  61  and calculates the length of the first light pattern  611  based on the first image  61 . In other embodiments, the first image-processing device of the first sensor  51  can receive the first image  61  and calculate the length of the first light pattern  611 . Next, the first image-processing device outputs the length of the first light pattern  611  to the controller  30 . In this way, controller  30  is not needed in calculating the length of the first light pattern  611  so that resources provided by the controller  30  can be spared. The way the length of the first light pattern  611  is measured has been explained above and will not be further explained herein. 
     In step S 103 , the controller  30  determines whether the length of the first light pattern  611  is greater than the first predetermined value TH 1 . If the length of the first light pattern  611  is not greater than the first predetermined value TH 1 , step S 104  follows. On the other hand, if the length of the first light pattern  611  is greater than the first predetermined value TH 1 , step S 105  follows. Specifically, the controller  30  determines whether the first light pattern  611  is in the first sensing area SR 1  or in the second sensing area SR 2  according to the length of the first light pattern  611 , and then adjusts the operating speed of the treadmill belt  20  accordingly. 
     In step S 104 , the controller  30  determines that the object A is in the first sensing area SR 1  of the treadmill belt  20 , that is to say, the controller  30  determines that the speed at which the object A moves is higher than the operating speed of the treadmill belt  20 . Next, the controller  30  increases the operating speed of the treadmill belt  20  through a driving module. Afterwards, step S 101  follows. In step S 105 , the controller  30  determines that the speed at which the object A moves is lower than the operating speed of the treadmill belt  20 . Next, the controller  30  decreases the operating speed of the treadmill belt  20  through a driving module. Afterwards, step S 101  follows. 
     Steps S 101  to S 105  will be repeated until the stop button on the treadmill (not shown in  FIGS. 1 and 2 ) is pressed. The start button and the stop button of the treadmill M can be the same button or two separate buttons. 
     In addition, the treadmill M can further include a second reflective component  42  and a second sensor  52 . Referring to  FIG. 2 , the second reflective component  42  is disposed on the second side  205  and corresponds to the first reflective component  41 . The second sensor  52  is coupled to the controller  30  and disposed on the second support rail  102 . It should be noted that the first sensor  51  can be disposed at a position where the first sensor  51  can detect the light reflected by the first reflective component  41  and the second reflective component  42 , in which the second sensor  52  omitted. 
     The second reflective component  42  has a high reflection coefficient and can be made of materials that are the same as or different from that of the first reflective component  41 . A person skilled in the art can choose the material of the second reflective component  42  according to actual needs. 
     The second sensor  52  retrieves a second image, which includes a second light pattern caused by light reflected by the second reflective component  42 . The second light pattern extends from a second starting point S 2  and, as with the first image  61 , changes according to the position of the object A. 
     The controller  30  can also determine whether the object A is in the first sensing area SR 1  or second sensing area SR 2  according to at least one of the length of the first light pattern  611  and the length of the second light pattern, in which the determination method is similar to the control method shown in the flow chart of  FIG. 11 . 
     More specifically, when the length of the first light pattern  611  changes and that of the second light pattern is not affected by the object A, the controller  30  adjusts the operating speed of the treadmill M according to the first image  61 . When the length of the second light pattern changes and that of first light pattern  611  is not affected by the object A, the controller  30  adjusts the operating speed of the treadmill M according to the second image. When the length of the first light pattern  611  and the second light pattern both change, the controller  30  adjusts the operating speed of the treadmill M according to any one of the first image  61  and the second image. 
     Furthermore, the present disclosure is not limited by the positions at which the first sensor  51 , the second sensor  52 , the first reflective component  41 , and/or second reflective component  42  are disposed as long as the first sensor  51  can detect the light reflected by the first reflective component  41  when there is no object on the treadmill M. The first sensor  51  can retrieve the whole first light pattern  611  or a part of the first light pattern  611 , e.g. three fourths or a half of the first light pattern  611 . However, the present disclosure is not limited thereto. In other embodiments, when an object A (user) is running on the treadmill M, the light reflected by the first reflective component  41  will be blocked by the object A, and then the controller  30  adjusts the treadmill belt  20  according to the characteristics of the first light pattern  611 ; when there is no object A (the user) on the treadmill M, the second sensor  52  can detect the light reflected by the second reflective component  42 , in which the second sensor  52  can retrieve the whole second light pattern or a part of the second light pattern, e.g. three fourths or a half of the second light pattern. When the object A is using the treadmill M, the light reflected by the second reflective component  42  will be blocked by the object A, and then the controller  30  adjusts the treadmill belt  20  according to the characteristics of the second light pattern. 
     Moreover, the second sensor  52  can further include a second image-processing device that retrieves the second image and calculates the length of the second light pattern according to the second image. Next, the second processing device outputs the length of the second light pattern to the controller  30 . The way in which the second image-processing device calculates the length of the second light pattern is similar to that used to calculate the length of the first light pattern  611 , and will not be further explained herein. 
     Furthermore, the second sensor  52  of the present disclosure further includes a second light emitter that provides light towards the second reflective component  42 . The second reflective component  42  reflects the light so as to generate the second light pattern. The second sensor  52  can be the same type of sensor as the first sensor  51 . The first sensor  51  and the second sensor  52  can be different types of sensors. The technical aspects relating to a sensor is common knowledge in the art, and thus will not be further explained herein. 
     Through the aforementioned technical means, the treadmill M of the present disclosure can adjust the operating speed of the treadmill belt  20  according to the position of the user, thereby providing a speed that is appropriate for the user. Accordingly, the user of the treadmill M does not need to press any button on the treadmill M to adjust the operating speed, and when the user is too tired to keep up with the speed of the treadmill M, the treadmill M will automatically slow down or shut down, which prevents accidents from happening. It should be noted that the controller  30  can output information related to the treadmill belt  20  to the control panel  103  so that the control panel  103  will alert the user, through lights or sounds that the operation of the treadmill M is about to be adjusted. In addition, the control panel  103  can display workout information in connection with the user, such as step frequency or running speed. 
     With reference to  FIG. 5  and  FIGS. 6A to 6C , the specific structure of the treadmill M′ according to another embodiment of the present disclosure is similar to that of the treadmill M, and the differences therebetween will be explained below. 
     The treadmill belt  20 ′ of the treadmill M′ is divided into a first sensing area SR 1 ′, a second sensing area SR 2 ′, and a third sensing area SR 3 ′. The second sensing area SR 2 ′ is between the first sensing area SR 1 ′ and the third sensing area SR 3 ′. The first sensing area SR 1 ′ is near the first sensor  51 ′. The first sensing area SR 1 ′, the second sensing area SR 2 ′, and the third sensing area SR 3 ′ are arranged in sequence along a track direction Z. Specifically, the first sensing area SR 1 ′, the second sensing area SR 2 ′, and the third sensing area SR 3 ′ correspond to the front region, the middle region and the rear region of the treadmill belt  20 ′ respectively. 
     The controller  30 ′ determines whether an object A′ is in the first sensing area SIC′, the second sensing area SR 2 ′ or the third sensing area SR 3 ′ according to the length of the first light pattern  611 ′ and then adjusts the operating speed of the treadmill belt  20 ′ accordingly. More specifically, the controller  30 ′ determines whether the object A′ is in the first sensing area SR 1 ′ or the second sensing area SR 2 ′ using a second predetermined value TH 2 , and then determines whether the object A′ is in the second sensing area SR 2 ′ or the third sensing area SR 3 ′ using a third predetermined value TH 3 . The determination methods involved will be further described below. 
     With reference to  FIG. 5 ,  FIGS. 6A to 6C  and  FIG. 12 , the control method in  FIG. 12  is applicable to the treadmill M′ shown in  FIG. 5 . Steps S 201  and S 202  are identical to steps S 101  and S 102 , and thus will not be explained herein. Steps S 203  to S 207  will be explained below. 
     In step S 203 , the controller  30 ′ determines whether the object A′ is in the first sensing area SR 1 ′ of the treadmill belt  20 ′ by determining whether the length of the first light pattern  611 ′ is greater than the second predetermined value TH 2 . 
     As shown in  FIG. 6A , if the length of the first light pattern  611 ′ of the first image  61 ′ is greater than the second predetermined value TH 2 , the controller  30 ′ determines that the object A′ is in the first sensing area SR 1 ′ of the treadmill belt  20 ′, i.e. the front region of the treadmill belt  20 ′. Specifically, the controller  30 ′ determines that the speed at which the object A′ moves is greater than the operating speed of the treadmill belt  20 ′. Next, step S 204  follows. In step S 204 , the controller  30 ′ increases the operating speed of the treadmill belt  20 ′ such that the treadmill belt  20 ′ moves as fast as the object A′ so that the object A′ can stay running in the middle of the treadmill belt  20 ′. Next, step S 201  follows. When the length of the first light pattern  611 ′ is greater than the second predetermined value TH 2 , step S 205  is performed. In step S 205 , the controller  30 ′ determines whether the length of the first light pattern  611 ′ is greater than the third predetermined value TH 3 , thereby determining whether the object A′ is in the second sensing area SR 2 ′ or the third sensing area SR 3 ′ of the treadmill belt  20 ′. 
     Referring to  FIG. 6B , when the length of the first light pattern  611 ′ is not greater than the third predetermined value TH 3 , i.e. the length of the first light pattern  611 ′ is between the second predetermined value TH 2  and the third predetermined value TH 3 , the controller  30 ′ determines that the object A′ is in the second sensing area SR 2 ′ of the treadmill belt  20 ′, i.e. the user is in the middle region of the treadmill belt  20 ′. In this step, the controller  30 ′ determines that the object A′ is moving as fast as the treadmill belt  20 ′, and then step S 206  follows. In step S 206 , the controller  30 ′ maintains the operating speed of the treadmill belt  20 ′, and then the control method returns to step S 201 . 
     As shown in  FIG. 6C , the controller  30 ′ determines that the object A′ is in the third sensing area SR 3 ′ of the treadmill belt  20 ′ when the length of the first light pattern  611 ′ is greater than the third predetermined value TH 3 , i.e. the controller  30 ′ determines that the object A′ is in the rear region of the treadmill belt  20 ′. The controller  30 ′ then determines that the object A′ moves at a speed lower than the operating speed of the treadmill belt  20 ′. Afterwards, step S 207  follows. In step S 207 , the controller  30 ′ decreases the operating speed of the treadmill belt  20 ′ such that the treadmill belt  20 ′ moves at the same rate as the object A′. Next, step S 201  is returned to, and the control method begins anew. 
     Similarly, steps S 201  to S 207  will be repeated until the stop button on the treadmill M′ (not shown in  FIG. 5 ) is pressed. 
     It should be noted that the second predetermined value TH 2  is one third of the distance between the first starting point S 1 ′ and the end point F 1 ′. The third predetermined value TH 3  is two thirds of the distance between the first starting point S 1 ′ and the end point F 1 ′. However, the present disclosure is not limited thereto. A person skilled in the art can set the second predetermined value TH 2  and the third predetermined value TH 3  according to actual needs. 
     In addition, the treadmill M′ of  FIG. 5  can further include a second reflective component  42 ′ and a second sensor  52 ′. The positions of the second reflective component  42 ′ and the second sensor  52 ′ and the structural relationship therebetween are similar to those of the second reflective component  42  and the second sensor  52  in the aforementioned embodiment, and therefore will not be further described herein. 
     The second sensor  52 ′ retrieves a second image, which includes the second light pattern provided by the second component  42 ′. The second light pattern of the second image changes according to the positions of the object A′ in a way that is similar to the way the first image  61 ′ changes. 
     The controller  30 ′ determines whether the object A′ is in the first sensing area SR 1 ′, second sensing area SR 2 ′, or third sensing area SR 3 ′ of the treadmill belt  20 ′ according to at least one of the length of the first light pattern  611 ′ and that of the second light pattern. Next, the controller  30 ′ adjusts the operating speed of the treadmill belt  20 ′ according to the position of the object A′. The way that the controller  30 ′ determines the length of the first light pattern  611 ′ and that of the second light pattern is similar to the flow chart shown in  FIG. 12 . 
     Specifically, when the length of the first light pattern  611 ′ changes and the second light pattern is not affected by the object A, the controller  30 ′ retrieves the first image  61 ′ to adjust the operating speed of the treadmill M′. When the first light pattern  611 ′ is not affected by the object A and the second light pattern changes, the controller  30 ′ retrieves the second image to adjust the operating speed of the treadmill M′. 
     In addition, the second sensor  52 ′ of the present embodiment can further include a second image-processing device and a second light emitter. The second image-processing device can calculate the length of the second image in a way that is similar to the way the length of the first light pattern  611 ′ is calculated, the details of which will not be reiterated herein. 
     It should be noted that, in the present embodiment, the treadmill belt  20 ′ is divided into three detection areas; however, the present disclosure is not limited thereto. In other embodiments, the treadmill belt  20 ′ can be divided into as many areas as needed. The number of detection areas can be varied according to actual needs. 
     Referring to  FIG. 7 , in this embodiment, the treadmill M″ includes a treadmill belt  20 ″, a first sensor  51 ″, a second sensor  52 ″, and a controller  30 ″. A first reflective component  41 ″ is disposed at a position near a first side  204 ″ of the treadmill belt  20 ″ and a second reflective component  42 ″ is disposed at a position near a second side  205 ″ of the treadmill belt  20 ″. The second side  205 ″ is on the opposite side of the first side  204 ″. The first sensor  51 ″ and the second sensor  52 ″ are identical to the first sensors and the second sensors in the aforementioned embodiments, and therefore will not be further explained herein. 
     With reference to  FIG. 7  and  FIGS. 8A to 8B , the first sensor  51 ″ retrieves the first image  61 ″ shown in  FIG. 8A  by receiving the light reflected by the first reflective component  41 ″. The second sensor  52 ″ retrieves the second image  62 ″ shown in  FIG. 8B  by receiving the light reflected by the second reflective component  42 ″. The first light pattern  611 ″ of the first image  61 ″ extends from the first starting point S 1 ” towards the end point F 1 “. The second light pattern  621 ” of the second image  62 ″ extends from the second starting point S 2 ″ towards the second end point F 2 ″. Afterwards, the length of the first light pattern  611 ″ and that of the second light pattern  621 ″ are applied to subsequent calculations performed by the controller  30 ″. 
     The differences among the treadmill M″ of the present embodiment, the treadmill M of  FIG. 2  and the treadmill M′ of  FIG. 7  is that the treadmill belt  20 ″ of the treadmill M″ is divided into a first detection area DR 1  adjacent to the first reflective component  41 ″ and a second detection area DR 2  neighboring the second reflective component  42 ″. The controller  30 ″ determines whether the object A″ is in the first detection area DR 1  or the second detection area DR 2  according to the length of the first light pattern  611 ″ or the second light pattern  621 ″. In practice, the treadmill belt  20 ″ is divided into left and right regions. The controller  30 ″ determines in which region the object A″ is located according to the length of the first light pattern  611 ″ and that of the second light pattern  621 ″ when the first light pattern  611 ″ and the second light pattern  621 ″ are covered. 
       FIG. 8A  and  FIG. 8B  show a case in which the first sensor  51 ″ and the second sensor  52 ″ respectively retrieve the first image  61 ″ and the second image  62 ″ at the same time. In this embodiment, neither the first light pattern  611 ″ of the first image  61 ″ nor the second light pattern  621 ″ of the second image  62 ″ is affected by the object A″. Accordingly, the controller  30 ″ determines that there is no object on the treadmill belt  20 ″. 
     The control method for controlling the treadmill belt  20 ″ of the treadmill M″ will be described below. With reference to  FIGS. 7, 9A to 9B, 10A to 10B and 13 , the control method shown in  FIG. 13  is applied to the treadmill M″ of  FIG. 7 . In step S 301 , the first sensor  51 ″ retrieves the first image  61 ″ after every specific time interval, and the second sensor  52 ″ retrieves the second image  62 ″ after every specific time interval. 
     In step S 302 , the controller  30 ″ receives the first image  61 ″ and the second image  62 ″ at the same time, and then performs steps S 303  and S 304 . In step S 303 , the controller  30 ″ calculates the length of the first light pattern  611 ″ according to the first image  61 ″, and then step S 305  follows. In step  304 , the controller  30 ″ calculates the length of the second light pattern  621 ″ according to the second image  62 ″, and then performs step S 305 . It should be noted that the method that the controller  30 ″ adopts to calculate the lengths of the first light pattern  611 ″ and the second light pattern  621 ″ is similar to that described above, and thus will not be explained herein. 
     In step S 305 , the controller  30 ″ determines whether the length of the first light pattern  611 ″ is greater than that of the second light pattern  621 ″. With the result of the determination, the controller  30 ″ can determine at which part of the treadmill belt  20 ″ the object A″ is located and then adjust the treadmill belt  20 ″ accordingly. 
     As shown in  FIGS. 9A and 9B , if the length of the first light pattern  611 ″ is greater than that of the second light pattern  621 ′, step S 306  is performed. In step S 306 , the controller  30 ″ determines that the object A″ is in the second detection area DR 2  of the treadmill belt  20 ″, that is to say, the light reflected by the second reflective component  42 ″ is partly blocked by the user on the treadmill belt  20 ″. The controller  30 ″ therefore determines that the user is near the second reflective component  42 ″, i.e. near the left side of the treadmill belt  20 ″, and then performs step S 308 . In step S 308 , the controller  30 ″ adjusts the treadmill belt  20 ″ accordingly through a driving module (not shown in  FIG. 7 ), e.g., the controller  30 ″ increases the slope of the treadmill belt  20 ″ from the left side so that the user shifts towards the other side of the treadmill belt  20 ″, that is, the side adjacent to the first reflective component  41 ″. Next, the control method returns to step S 301 . 
     With reference to  FIG. 10A  and  FIG. 10B , if the length of the first light pattern  611 ″ is not greater than that of the second light pattern  621 ″, the controller  30 ″ performs step S 307 . In step S 307 , the controller  30 ″ determines that the object A″ is located at the first detection area DR 1  of the treadmill belt  20 ″. In other words, the light reflected by the first reflective component  41 ″ is blocked by the user on the right side of the treadmill belt  20 ″. Next, the controller  30 ″ performs step S 309 . In step S 309 , the controller  30 ″ adjusts the treadmill belt  20 ″ accordingly. For example, the controller  30 ″ increases the slope of the treadmill belt  20 ″ from the right side so that the user shifts towards the left side of the treadmill belt  20 ″, i.e. the side near the second reflective component  42 ″. Next, step S 301  is returned to, and the control method begins anew. 
     Steps S 301  to S 309  will be repeated until the stop button (not shown in  FIG. 7 ) is pressed. 
     Through the technical means provided by the present disclosure, the treadmill M″ can adjust the treadmill belt  20 ″ according to the position of the user. Therefore, when a user runs on one side of the treadmill belt  20 ″ out of habit, the controller  30 ″ will increase the slope of said side of the treadmill belt  20 ″, thereby reducing the risk of a fall. Furthermore, through the constant adjustment of the treadmill belt  20 ″, the user is able to stay running in the middle of the treadmill belt  20 ″, which helps improve the running posture of the user and reduce uneven pressure distribution applied on the treadmill M″, by which treadmill M″ can have a longer lifespan. 
     Moreover, the controller  30 ″ can also determine the exercise state of the object A″ according to the length variation of the first light pattern  611 ″ or the second light pattern  621 ″ over time. More specifically, when in different exercise states, e.g. running and walking, the user&#39;s step frequency differs. Therefore, by calculating the length variations of the first light pattern  611 ″ and second light pattern  621 ″, the controller  30 ″ can determine the exercise state of the user. 
     In addition, in other embodiments, the first reflective components ( 41 ,  41 ′,  41 ″) and the second reflective components ( 42 ,  42 ′,  42 ″) can be replaced by first light emitters and second light emitters respectively, in which the first light emitters project light onto the first sensor ( 51 ,  51 ′,  51 ″) so that the first sensor can retrieve the first light pattern, and the second light emitters project light onto the second sensor ( 52 ,  52 ′,  52 ″) so that the second sensor can retrieve the second light pattern. 
     With reference to  FIGS. 14A and 14B , the treadmill N provided by one embodiment of the present disclosure includes a treadmill belt  20 , an image sensor  53 , and a controller  70 . The controller  70  is coupled to the image sensor  53 . Specifically, the treadmill N further includes a frame body  10  and a control panel  103  disposed on the frame body  10 . The controller  70  can be disposed in the control panel  103 . The control panel  103  provides the user with information such as the running speed, running time and/or warnings. Furthermore, the control panel  103  can adjusts the treadmill belt  20  through the above mentioned information. The frame body  10  includes a first support rail  101  and a second support rail  102  that are disposed on both sides of the treadmill belt  20  at an end thereof. The first support rail  101  and the second support rail  102  extend upwardly. The treadmill belt  20  includes a walking belt  202  and a support base  203  that supports the walking belt  202 . The object A refers to the user of the treadmill N. 
     As shown in  FIG. 14B , the image sensor  53  includes an image sensing unit  531 . In the present embodiment, the image sensor  53  further includes a light emitter  533 . The light emitter  533  is a light source that emits invisible light, such as infrared or light with a wavelength greater than 850 nm. It should be noted that the light emitter  533  can be exemplified in other ways; the present disclosure is not limited to the above example. 
     In this embodiment, the treadmill N includes one image sensing unit and one light emitter; however, the present disclosure is not limited thereto. In other embodiments, the numbers of the image sensing unit and the light emitter can respectively be more than one. 
     The image sensing unit  531  of the image sensor  53  retrieves an image of the object A (the user of the treadmill N). The image sensing unit  531  retrieves the image of the object A after every specific time interval. The controller  70  adjusts the operating speed of the treadmill belt  20  according to the characteristic properties of the image. The characteristic properties can be the percentage of the pixels in the image that represent the object A or the distribution manner thereof 
     Referring to  FIGS. 14A and 15A to 15C , the image  151  is an image that contains the object A. The  figure 1511  in the image  151  corresponds to the object A, which is formed of a plurality of pixels. Since the image sensor  53  is disposed at the front end of the treadmill N, the closer the object A is to the front end  201  of the treadmill N, the higher the percentage of pixels representing the object A is. In other words, the farther the object A is from the front end  201  of the treadmill N, the lower the percentage of the pixels representing the object A. The controller  70  can adjust the operating speed of the treadmill belt  20  according to the percentage of the pixels that constitute the  figure 1511  such that the object A can remain in the middle of the treadmill belt  20 . 
     As shown in  FIG. 15B , the image  152  retrieved by the image sensing unit  531  contains a  figure 1521  that corresponds to the object A. In the image  152 , the percentage of the pixels constituting the  figure 1521  is higher than the percentage of the pixels constituting the  figure 1511  in the image  151 . Therefore, the object A is positioned closer to the front end  201  of the treadmill N in the embodiment shown in  FIG. 15B  than in the embodiment shown in  FIG. 15A . 
     As shown in  FIG. 15C , the image  153  contains a  figure 1531  corresponding to the object A. In the image  153 , the percentage of the pixels constituting the  figure 1531  is lower than the percentage of the pixels constituting the  figure 1511  in the image  151 . Therefore, the object A is positioned farther from the front end  201  of the treadmill N in the embodiment shown in  FIG. 15C  than in the embodiment shown in  FIG. 15A . 
     The controller  70  adjusts the operating speed of the treadmill belt  20  by the distance between the object A and the front end  201  according to the percentage of the pixels representing the object A in the image retrieved by the image sensor  53 . In this way, the object A can remain in the middle of the treadmill belt  20 . 
     In one embodiment, the controller  70  can determine whether the object A is moving faster or slower than the treadmill belt  20  by detecting and determining if the object A is too close to the front end  201  or too far from the front end  01  and then increase or decrease the operating speed of the treadmill belt  20  through a driving module (not shown) so that the object A can remain moving in the middle of the treadmill belt  20 . 
     For example, when the number or percentage of the pixels corresponding to the object A in the image retrieved by the image sensing unit  531  is greater than a predetermined value then the controller  70  determines that the object A is too close to the front end  201 . When the number or percentage of the pixels corresponding to the object A in the image retrieved by the image sensing unit  531  is smaller than a predetermined value then the controller  70  determines that the object A is too far from the front end  201 . 
     Furthermore, the controller  70  can automatically start the treadmill belt  20  if the object A is too close to the front end  201 . In that case, the distance between the object A and the front end  201  when the controller  70  starts the treadmill belt  20  can be smaller than the distance between the object A to the front end  201  when the controller starts increasing the operating speed of the treadmill belt  20 . 
     The controller  70  also can automatically stop the treadmill belt  20  if the object A is too far from the front end  201 . In that case, the distance from the object A to the front end  201  when the controller starts the treadmill belt  20  can be greater than the distance from the object A to the front end  201  when the controller starts decreasing the operating speed of the treadmill belt  20 . 
     In one embodiment of the present disclosure, the controller  70  can determine whether the object A is gradually increasing or decreasing the running speed by detecting and determining if the number or percentage of the pixels corresponding to the object A in the image retrieved by the image sensing unit  531  gradually increases or decreases and then correspondingly increase or decrease the operating speed of the treadmill belt  20  through a driving module (not shown) so that the object A can remain moving in the middle of the treadmill belt  20 . 
     In one embodiment of the present disclosure, the controller  70  can determine the step frequency of the user by calculating the variation frequency of the pixels in the image that correspond to the object A. The step frequency can be a reference for the user&#39;s exercise performance. 
     The technical aspects concerning the image sensor  53  and the controller  70  are common knowledge in the art, and therefore will not be further described herein. 
     In one embodiment of the present disclosure, the light emitter  533  of the image sensor  53  emits light that illuminates the object A. The image retrieved by the image sensing unit  531  includes a figure corresponding to the object A that is formed by light emitted from the light emitter  533  and reflected by a reflective component. The light emitter  533  can emit invisible light; however, the present disclosure is not limited thereto. In other embodiments, the light emitter  533  can emit both visible and invisible light so that the treadmill of the present disclosure can operate in any environment. 
     Through the technical means provided by the present disclosure, the treadmill N can start, stop, or adjust the treadmill belt  20  according to the position of the user, thereby providing the user with an appropriate operating speed that conforms to the physical condition of the user. The user does not need to press any button on the treadmill to adjust the operating speed of the treadmill belt. When the user is too tired to keep up with the speed of the treadmill belt  20 , the treadmill will automatically slow down or shut down, reducing the risk of accidents when the user is unable to reach the stop button. It should be noted that the control panel  103  can inform the user of an upcoming adjustment of the treadmill N with alerting sounds or light. In addition, the control panel  103  can show the exercise information of the user, such as running speed or exercise state. 
     The control method for controlling the treadmill belt of the treadmill N will be described below. With reference to  FIGS. 14A, 14B and 16 , the control method shown in  FIG. 16  is applicable to the treadmill N shown in  FIG. 14A . In the present embodiment, a predetermined value TH 161  and a predetermined value TH 163  can be set in the controller  70 . The predetermined value TH 161  and the predetermined value TH 163  respectively represent a number or a percentage of the pixels corresponding to the object A in the image retrieved by the image sensing unit  531 . 
     In step S 161 , the image sensing unit  531  of the image sensor  53  retrieves an image of the object A. The image sensing unit  531  contains a plurality of pixels, which means that every image retrieved by the image sensing unit  531  includes a plurality of pixels as well. 
     In step S 162 , the controller  70  determines whether the percentage of the pixels corresponding to the object A is smaller than the predetermined value TH 161 . If so, the controller  70  performs step S 163 . If not, the controller  70  performs step S 164 . In step S 163 , since the controller  70  determines that in the image retrieved by the image sensing unit  531 , the percentage of the pixels corresponding to the object A is smaller than the predetermined value TH 161 , which means that the object A is too far from the front end  201  of the treadmill N and is moving slower than the treadmill belt  20 , the controller  70  decreases the operating speed of the treadmill belt  20  through a driving module (not shown) accordingly so that the object A can remain in the middle of the treadmill belt  20 . Next, the control method returns to step S 161 . 
     In step S 164 , the controller  70  determines whether the percentage of the pixels corresponding to the object A is greater than the predetermined value TH 163 . If so, the controller  70  performs step S 165 ; if not, the controller  70  performs step S 161 . In step S 165 , since the controller  70  determines that in the image retrieved by the image sensing unit  531 , the percentage of the pixels corresponding to the object A is greater than the predetermined value TH 163 , which means that the object A is too close to the front end  201  of the treadmill N and is moving faster than the treadmill belt  20 , the controller  70  increases the operating speed of the treadmill belt  20  through a driving module (not shown) accordingly so that the object A can remain in the middle of the treadmill belt  20 . 
     It should be noted that the predetermined value TH 161  and the predetermined value TH 163  described above are not to limit the scope of the present disclosure. A person skilled in the art can set up the predetermined value TH 161  and predetermined value TH 163  according to actual needs. 
     With reference to  FIGS. 14A, 14B and 17 , the control method of  FIG. 17  is applicable to the treadmill N of  FIG. 14A . 
     In step S 171 , the image sensing unit  531  of the image sensor  53  retrieves an image of the object A. The image sensing unit  531  includes a plurality of pixels, which means that every image retrieved by the image sensing unit  531  is formed of a plurality of pixels as well. 
     Next, in step S 172 , the controller  70  determines whether the percentage of the pixels corresponding to the object A in the image retrieved by the image sensing unit  531  is decreasing. If so, the controller  70  performs step S 173 ; if not, the controller  70  performs step S 174 . In step S 173 , since the controller  70  determines that in the image retrieved by the image sensing unit  531 , the percentage of the pixels corresponding to the object A is decreasing, which means that the object A is getting further from the front end  201  of the treadmill N and is moving faster than the treadmill belt  20 , the controller  70  decreases the operating speed of the treadmill belt  20  through a driving module (not shown) accordingly so that the object A can remain in the middle of the treadmill belt  20 . Next, step S 171  follows, and the control method begins anew. 
     In step S 174 , the controller  70  determines whether the percentage of the pixels corresponding to the object A in the image retrieved by the image sensing unit  531  is increasing. If so, the controller  70  performs step S 175 ; if not, step S 171  follows, and the control method begins anew. In step S 175 , since the controller  70  determines that in the image retrieved by the image sensing unit  531 , the percentage of the pixels corresponding to the object A is increasing, which means that the object A is getting closer to the front end  201  of the treadmill N and is moving faster than the treadmill belt  20 , the controller  70  decreases the operating speed of the treadmill belt  20  through a driving module (not shown) accordingly so that the object A can remain in the middle of the treadmill belt  20 . 
     Referring to  FIGS. 14A, 14B and 18 , the control method shown in  FIG. 18  is applicable to the treadmill N of  FIG. 14A . In the present embodiment, a predetermined value TH 181  and a predetermined value TH 183  can be set in the controller  70 , in which the predetermined value TH 181  and the predetermined value TH 183  respectively correspond to a percentage of the pixels representing the object A. 
     In step S 181 , the image sensing unit  531  of the image sensor  53  retrieves an image of the object A. The image sensing unit  531  includes a plurality of pixels, which means that every image retrieved by the image sensing unit  531  is formed of a plurality of pixels. 
     Next, in step S 182 , the controller  70  determines whether the percentage of the pixels corresponding to the object A in the image retrieved by the image sensing unit  531  is greater than the predetermined value TH 181 . If so, the controller  70  performs step S 183 ; if not, step S 181  follows, and the control method begins anew. In step S 183 , since the controller  70  determines that in the image retrieved by the image sensing unit  531 , the percentage of the pixels corresponding to the object A is greater than the predetermined value TH 181 , which means that the object A (user) is already standing at a predetermined position on the treadmill belt  20 , the controller  70  starts the treadmill belt  20  accordingly. 
     Next, in step S 184 , the controller  70  determines whether the percentage of the pixels corresponding to the object A in the image retrieved by the image sensing unit  531  is smaller than the predetermined value TH 183 . If so, the controller  70  performs step S 185 ; if not, the controller  70  performs step S 186 . In step S 183 , since the controller  70  determines that in the image retrieved by the image sensing unit  531 , the percentage of the pixels corresponding to the object A is smaller than the predetermined value TH 183 , which means that the object A (the user) is already standing at a predetermined position on the treadmill belt  20 , the controller  70  stops the treadmill belt  20  accordingly. 
     It should be noted that the predetermined value TH 181  and the predetermined value TH 183  described above are not to limit the scope of the present disclosure. A person skilled in the art can set the predetermined value TH 181  and predetermined value TH 183  according to actual needs. 
     With reference to  FIGS. 19, 20A and 20B , the treadmill N′ provided by another embodiment of the present disclosure includes a treadmill belt  20 ′, an image sensor  53 ′, and a controller  70 ′. The controller  70 ′ is coupled to the image sensor  53 ′. Specifically, the treadmill N′ further includes a frame body  10  and a control panel  103  disposed on the frame body  10 . The controller  70 ′ can be disposed in the control panel  103 . The frame body  10  includes a first support rail  101  and a second support rail  102  that are disposed on both sides of the treadmill belt  20 ′ at an end thereof. The first support rail  101  and the second support rail  102  extend upwardly. The treadmill belt  20 ′ includes a walking belt  202  and a support base  203  that supports the walking belt  202 . The object A′ refers to the user of the treadmill N′. 
     The difference between the treadmill N of  FIG. 14  and the treadmill N′ of the present embodiment is that the treadmill belt  20 ′ of the treadmill N′ is divided into a first detection area DR 1 ′ adjacent to a first side  214  and a second detection area DR 2 ′ adjacent to the second side  215 . The image sensor  53 ′ is located between the first side  214  and the second side  215 . Referring to  FIGS. 20A and 20B , the image  191  and  192  retrieved by the image sensing unit of the image sensor  53 ′ is divided into a first image zone ( 1911  in  FIG. 20A and 1921  in  FIG. 20B ) close to the first side  214  of the treadmill belt  20 ′ and a second image zone ( 1913  in  FIG. 20A and 1923  in  FIG. 20B ) close to the second side  215  of the treadmill belt  20 ′. 
     In the present embodiment, the controller  70 ′ determines whether the object A′ is in the first detection area DR 1 ′ or the second detection area DR 2 ′ according to the image retrieved by the image sensor  53 ′ and adjusts the treadmill belt  20 ′ accordingly. 
     With reference to  FIG. 20A , in this embodiment, a predetermined value can be set (not shown) in the controller  70 ′. The predetermined value corresponds to a percentage of the pixels in the first image zone  1911  that represents the object A′. In the image  191 , the  figure 1915  corresponds to the object A′. When the percentage of the pixels in the  figure 1915  is larger than the predetermined value, the controller  70 ′ determines that the object A′ is in the first detection area DR 1 ′ of the treadmill belt  20 ′. 
     Accordingly, the controller  70 ′ adjusts the treadmill belt  20 ′ through a driving module (not shown). For example, the controller  70 ′ increases the slope of the treadmill belt  20 ′ from the first side  214  such that the user shifts towards the second side  215  of the treadmill belt  20 ′, whereby the user can remain in the middle of the treadmill belt  20 ′. 
     As shown in  FIG. 20B , in this embodiment, a predetermined value can be set (not shown) in the controller  70 ′. The predetermined value corresponds to a percentage of the pixels in the second image zone  1923  that represents the object A′. In the image  192 , the  figure 1925  corresponds to the object A′. When the percentage of the pixels in the  figure 1925  is larger than the predetermined value, the controller  70 ′ determines that the object A′ is in the second detection area DR 2 ′ of the treadmill belt  20 ′. 
     Accordingly, the controller  70 ′ adjusts the treadmill belt  20 ′ through a driving module (not shown). For example, the controller  70 ′ increases the slope of the treadmill belt  20 ′ from the second side  215  such that the user shifts towards the first side  214  of the treadmill belt  20 ′, whereby the user can remain in the middle of the treadmill belt  20 ′. 
     Through the technical means provided by the present disclosure, the treadmill N′ can adjust the treadmill belt  20 ′ according to the position of the user. Therefore, when a user runs on a side of the treadmill belt  20 ′ out of habit, the controller  70 ′ will increase the slope of the side of the treadmill belt  20 ′ where the user is running, thereby reducing the risk of a fall. Furthermore, through the constant adjustment of the treadmill belt  20 ′, the user maintains running in the middle of the treadmill belt  20 ′, which helps improve the running posture adopted by the user and reduce uneven pressure distribution applied on the treadmill N′, by which treadmill M″ can have a longer lifespan. 
     The control method for controlling the treadmill belt of the treadmill N′ will be explained below. With reference to  FIGS. 19, 20A, 20B and 21 , the control method shown in  FIG. 21  is applicable to the treadmill N′ of  FIG. 19 . In the present embodiment, a predetermined value TH 211  and a predetermined value TH 213  can be set in the controller  70 ′, in which the predetermined value TH 211  corresponds to a percentage of pixels in the first image zone that represent the object A′, and the predetermined value TH 213  corresponds to a percentage of pixels in the second image zone that represent the object A′. 
     In step S 211 , the image sensing unit of the image sensor  53 ′ retrieves an image of the object A′ (the user of the treadmill N′). Since the image sensing unit includes a plurality of pixels, every image retrieved by the image sensing unit is formed of a plurality of pixels. 
     In step S 212 , the controller  70 ′ determines whether the percentage of the pixels in the first image zone that correspond to the object A′ is greater than the predetermined value TH 211 . If so, the controller  70 ′ performs step S 213 ; if not, the controller  70 ′ performs step S 215 . In step S 213 , since the percentage of the pixels in the first image zone that correspond to the object A′ is greater than the predetermined value TH 211 , the controller  70 ′ determines that the object A′ is in the first detection area DR 1 ′ of the treadmill belt  20 ′. Next, in step S 215 , the controller  70 ′ adjusts the treadmill belt  20 ′ accordingly. For example, the controller  70 ′ increases the slope of the treadmill belt  20 ′ from the first side  214  such that the user shifts towards the second side  215 . Next, the control method returns to step S 211 . 
     In step S 215 , the controller  70 ′ determines whether the percentage of the pixels in the second image zone that correspond to the object A′ is greater than the predetermined value TH 213 . If so, the controller  70 ′ performs step S 216 ; if not, step S 211  follows, and the control method begins anew. In step S 216 , since the percentage of the pixels in the second image zone that correspond to the object A′ is greater than the predetermined value TH 213 , the controller  70 ′ determines that the object A′ is in the second detection area DR 2 ′ of the treadmill belt  20 ′. Next, in step S 217 , the controller  70 ′ adjusts the treadmill belt  20 ′ accordingly. For example, the controller  70 ′ increases the slope of the treadmill belt  20 ′ from the second side  215  such that the user runs towards the first side  214 . Next, the control method returns to step S 211 . 
     It should be noted that the predetermined value TH 211  and the predetermined value TH 213  described above are not to limit the scope of the present disclosure. A person skilled in the art can set the predetermined value TH 211  and predetermined value TH 213  according to actual needs. 
     Referring to  FIG. 22  and  FIG. 23 , the treadmill N″ provided by another embodiment of the present disclosure includes a treadmill belt  20 ″, an image sensor  53 ″, and a controller  70 ″. The controller  70 ″ is coupled to the image sensor  53 ″. Specifically, the treadmill N″ further includes a frame body  10  and a control panel  103  disposed on the frame body  10 . The controller  70 ″ can be disposed in the control panel  103 . The frame body  10  includes a first support rail  101  and a second support rail  102  that are disposed on both sides of the treadmill belt  20 ″ at an end thereof. The first support rail  101  and the second support rail  102  extend upwardly. The treadmill belt  20 ′ includes a walking belt  202  and a support base  203  that supports the walking belt  202 . The object A″ refers to the user of the treadmill N″. The treadmill N″ of the present embodiment and the treadmill N and treadmill N′ of the aforementioned embodiments share a similar structure, and the differences therebetween will be explained below. 
     The image sensor  53 ′ in the present embodiment further includes an image processing unit (not shown). The image sensor  53 ″ retrieves an image of the object A″ (a user of the treadmill N″) after every specific time interval. The controller  70 ″ adjusts the treadmill belt  20 ″ according to a characteristic property of the image, in which the characteristic property can be the percentage of the pixels corresponding to the object A″ or the distribution manner thereof. In this embodiment, the characteristic property is the distribution manner of the pixels corresponding to the object A″ in the image, the details of which are described below. 
     The image sensing unit of the image sensor  53 ″ retrieves an image of the object A″ which is then received by the image processing unit. The image processing unit calculates a dynamic gesture image corresponding to a gesture G made by the object A″ with a hand H, and then outputs the dynamic gesture image to the controller  70 ″. The controller  70 ″ issues a control command according to the dynamic gesture image G′ to adjust the treadmill belt  20 ″. 
     With reference to  FIG. 23 , the image sensing unit of the image sensor  53 ″ retrieves an image  231  of the object A″. The  figure 2311  in the image  231  corresponds to the object A″, and the dynamic gesture image G′ corresponds to the gesture G made by the object A″ with the hand H. The dynamic gesture image G′ can be a first image, a hands-spread-out image, a waving image, a hands-rotating-clockwise image, a hands-rotating-counterclockwise image, a hands-moving-up image, a hands-moving-down image, an arm-held-up image, an arm-laid-down image, an arm-held-out image, an arms-held-up image, an arms-laid-down image, and an arms-spread-out image. However, the present disclosure is not limited thereto. 
     After receiving the image  231  of the object A″, the image processing unit of the image sensor  53 ″ can calculate the dynamic gesture image G′ that corresponds to the gesture G made by the object A″ with the hand H. The image sensor  53 ″ then outputs the dynamic gesture image G′ to the controller  70 ″. The controller  70 ″ issues a control command according to the dynamic gesture image G′ so as to perform certain operations on the treadmill belt  20 ″ such as startup, shut down, or speed adjustment. 
     Referring to  FIG. 24 , when the gesture G is “holding up both hands”, the image processing unit of the image sensor  53 ″ calculates the dynamic gesture image G′ that corresponds to the gesture G and then the image sensor  53 ″ outputs the dynamic gesture image G′ to the controller  70 ″. The controller  70 ″ sends out a control command to start the treadmill belt  20 ″. In this embodiment, the control command that corresponds to the gesture “waving hands” is to stop the treadmill belt  20 ″; the control command that corresponds to the gesture “rotating hands clockwise” is to increase the operating speed of the treadmill belt  20 ″; the control command corresponding to the gesture “rotating hands counterclockwise” is to decrease the operating speed of the treadmill belt  20 ″; the control command corresponding to the gesture “moving hands up” is to increase the slope of the treadmill belt  20 ″; the control command corresponding to the gesture “moving hands down” is to decrease the slope of the treadmill belt  20 ″. Through the above technical means, the present disclosure realizes automatic adjustment of the treadmill belt  20 ″ according to the gesture G made by the object A″ with the hand H. 
     The gestures and commands listed in  FIG. 24  are for exemplary purpose only. A person skilled in the art can design various gestures and the corresponding commands in accordance with actual needs. The techniques involved in the implementation of the image sensor  53 ″ and the controller  70 ″ are common knowledge in the art, and thus will not be further explained herein. 
     Through the technical means provided by the present disclosure, the treadmill N″ can start, stop or adjust the treadmill belt  20 ″ according to the gesture made by the user, whereby the user does not need to press any button on the treadmill N″ to adjust the treadmill belt  20 ″ during usage; instead, the treadmill performs various operations automatically. 
     The control method for controlling the treadmill belt of the treadmill N″ will be explained below. With reference to  FIGS. 22, 23 and 25 , the control method shown in  FIG. 25  is applicable to the treadmill N″ of  FIG. 22 . 
     In step S 251 , the image sensing unit of the image sensor  53 ″ retrieves an image  231  of the object A″ (a user of the treadmill N″), in which the object A″ is making a gesture G. Next, in step S 252 , the image processing unit of the image sensor  53 ″ calculates the dynamic gesture image G′ that corresponds to the gesture G according to the image  231 . The image sensor  53 ″ then outputs the dynamic gesture image G′ to the controller  70 ″. Next, in step S 253 , the controller  70 ″ issues a control command to adjust the treadmill belt  20 ″ according to the dynamic gesture image G′. For example, the controller  70 ″ sends out a command that starts, stops or adjusts the treadmill belt  20 ″. Through the above technical means, the present disclosure realizes automatic adjustment of the treadmill belt  20 ″ according to the gesture G made by the object A″ with the hand H. 
     In summary, the present disclosure provides a treadmill and a control method for controlling the treadmill belt thereof that retrieves images using a sensor. A controller adjusts the operating speed of the treadmill belt according to the length of the light pattern in the image. Therefore, the present disclosure can determine the physical condition or the running rate of the user according to the position of the user, and then increase or decrease the operating speed of the treadmill belt or stop the treadmill belt, which can prevent accidents that might happen when the user is too exhausted to keep running at a certain pace. 
     Furthermore, the treadmill and the control method for the treadmill belt thereof can compare the length of the first light pattern with that of the second light pattern using the controller, and the controller can adjust the treadmill belt according to the result of the comparison. Specifically, the treadmill of the present disclosure can adjust the slope of the treadmill according to whether the user is running on the left part or the right part of the treadmill belt so that the user can remain running in the middle of the treadmill belt, which improves the running posture and uneven pressure distribution applied to the treadmill. The lifespan of the treadmill can thereby be extended. 
     Moreover, the controller of the treadmill of the present disclosure can adjust the operating speed of the treadmill belt according to the percentage of the pixels corresponding to the user in the image retrieved by the image sensor. In addition, the controller can adjust the treadmill belt according to the dynamic gesture image derived from the image retrieved by the image sensor, thereby providing automatic adjustment of the treadmill belt without the user having to manually operate the treadmill. 
     The description illustrated supra set forth simply the preferred embodiments of the present disclosure; however, the characteristics of the present disclosure are by no means restricted thereto. All changes, alterations, or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the present disclosure delineated by the following claims.