Patent Publication Number: US-10783645-B2

Title: Apparatuses, methods, and storage medium for preventing a person from taking a dangerous selfie

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Application claims priority of Taiwan Application No. 106145980, filed on Dec. 27, 2017, and the entirety of which is incorporated by reference herein. 
     BACKGROUND OF THE APPLICATION 
     Field of the Application 
     The application relates generally to imaging applications or services, and more particularly, to apparatuses, methods, and storage medium for preventing a person from taking a dangerous selfie. 
     Description of the Related Art 
     With the rapid development of imaging technology, most mobile electronic apparatuses are equipped with front cameras to allow the user to take selfies. In a typical selfie scenario using a cellphone, the user may operate the cellphone either manually or using an assisting device (e.g., a selfie stick) to allow the front camera to face the user, and to take a picture of the user and/or the background. In addition, before taking the picture, the user may confirm the view of the front camera, which is displayed on the screen of the cellphone. 
     However, there are situations where accidents may occur in such selfie scenarios due to the user not noticing the dangerous environment behind him or her while taking the selfie. For example, the user may be taking a selfie near a cliff in some scenic area, or near the edge of a high spot in a building, and then accidentally fall from the high place. Therefore, it is desirable to have a solution for detecting and preventing dangerous selfies. 
     BRIEF SUMMARY OF THE APPLICATION 
     In one aspect of the application, a method for preventing a person from taking a dangerous selfie, executed by a mobile electronic apparatus comprising a multi-axis sensing device and an image acquisition device disposed on a surface of the mobile electronic apparatus, is provided. The method comprises the following steps: using the image acquisition device operating in a shooting mode to capture an image of the person in a background; using the multi-axis sensing device to detect orientation information of the mobile electronic apparatus; determining whether the person is in a potentially dangerous environment according to the orientation information and the image; and enabling the image acquisition device to suspend or exit the shooting mode when the person is in the potentially dangerous environment. 
     In another aspect of the application, a mobile electronic apparatus comprising an image acquisition device, a multi-axis sensing device, and a controller is provided. The image acquisition device is disposed on a surface of the mobile electronic apparatus, and is configured to capture an image of a person in a background. The multi-axis sensing device is configured to detect orientation information of the mobile electronic apparatus. The controller is configured to determine whether the person is in a potentially dangerous environment according to the orientation information and the image, and enable the image acquisition device to suspend or exit the shooting mode when the person is in the potentially dangerous environment. 
     Other aspects and features of the application will become apparent to those with ordinary skill in the art upon review of the following descriptions of specific embodiments of the method for preventing a person from taking a dangerous selfie and the mobile electronic apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The application can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  is a block diagram illustrating the system architecture of a mobile electronic apparatus according to an embodiment of the application; 
         FIG. 2  is a flow chart illustrating the method for preventing a person from taking a dangerous selfie according to an embodiment of the application; 
         FIGS. 3A and 3B  show a flow chart illustrating the method for preventing a person from taking a dangerous selfie according to another embodiment of the application; 
         FIG. 4  is a schematic diagram illustrating an exemplary orientation of the mobile electronic apparatus; 
         FIG. 5  is a schematic diagram illustrating the determination of whether the person in the image is in a potentially dangerous environment according to an embodiment of the application; 
         FIG. 6A  depicts an exemplary image captured by the image acquisition device; 
         FIG. 6B  depicts the distribution of the variations of grey scales of the pixels along the earth-line k; 
         FIG. 6C  depicts another exemplary image captured by the image acquisition device; 
         FIG. 6D  depicts the distribution of the variations of grey scales of the pixels along the earth-line m; and 
         FIGS. 7A and 7B  show a flow chart illustrating the method for preventing a person from taking a dangerous selfie according to yet another embodiment of the application. 
     
    
    
     DETAILED DESCRIPTION OF THE APPLICATION 
     The following description is made for the purpose of illustrating the general principles of the application and should not be taken in a limiting sense. It should be understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
       FIG. 1  is a block diagram illustrating the system architecture of a mobile electronic apparatus according to an embodiment of the application. The mobile electronic apparatus  100  includes an image acquisition device  10 , a display device  20 , a multi-axis sensing device  30 , a Global Positioning System (GSP) device  40 , a controller  50 , and a storage device  60 . The image acquisition device  10 , the display device  20 , the multi-axis sensing device  30 , the GSP device  40 , and the storage device  60  are coupled to the controller  50 . In addition, the display device  20  and the storage device  60  are coupled to the image acquisition device  10 . 
     The mobile electronic apparatus  100  may be a hand-held image or video camera, a cellphone or smartphone, a panel Personal Computer (PC), or any computing device supporting the selfie function. 
     The image acquisition device  10  may support different operation modes. When operating in the shooting mode, the image acquisition device  10  may capture images and support the function of digital zooming. When operating in the protection mode, the image acquisition device  10  may be suspended from capturing images, to protect the user from injury due to taking a selfie. The image acquisition device  10  may include one or more optics, such as see-through lens, and/or image sensors. In one embodiment, the mobile electronic apparatus  100  may be a smartphone, and the image acquisition device  10  may include the front camera and/or the back camera of the smartphone. In another embodiment, the image acquisition device  10  may include a three-dimensional (3D) camera which may be configured to capture images and obtain the depth information of the objects in the captured images (i.e., the distance from the mobile electronic apparatus  100  to the objects). The images captured by the image acquisition device  10  may be sent to the display device  20  for display, or may be sent to the controller  50  to be forwarded to the display device  20 , or may be sent to the storage device  60  to be stored therein. 
     The display device  20  is responsible for displaying visual content and/or texts, such as the images captured by the image acquisition device  10 . The display device  20  may be a Liquid-Crystal Display (LCD), Light-Emitting Diode (LED) display, Organic LED (OLED) display, Electronic Paper Display (EPD), or Cathode Ray Tube (CRT) display, etc. In one embodiment, the display device  20  may further include one or more touch sensors disposed thereon or thereunder for sensing touches, contacts, or approximations of objects, such as fingers or styluses, enabling the display device  20  to serve as an input device. 
     In one embodiment, both the image acquisition device  10  and the display device  20  may be disposed on the front surface of the mobile electronic apparatus  100  (e.g., the surface on which the user operates a smartphone). 
     In another embodiment, the image acquisition device  10  and the display device  20  may be disposed on different surfaces of the mobile electronic apparatus  100 . For example, the image acquisition device  10  may be disposed on the back surface of the mobile electronic apparatus  100 , and the display device  20  may be disposed on the front surface of the mobile electronic apparatus  100 , wherein the display device  20  may be adhered to a mechanical structure which may move the display device  20  to face the same direction as the image acquisition device  10  does. For example, the display device  20  may be a revolvable screen. 
     The multi-axis sensing device  30  may include one or more types of sensor(s), such as an acceleration sensor, a magneto sensor (also called an electrical compass), a gyroscope sensor, and/or an altitude sensor. The acceleration sensor may be used to detect the acceleration of the mobile electronic apparatus  100 . The magneto sensor may be used to detect changes in the magnetic field. The gyroscope sensor may be used to detect the angular velocity of the mobile electronic apparatus  100 . The altitude sensor may be used to detect the horizontal height of the mobile electronic apparatus  100 . Based on the detection result provided by the multi-axis sensing device  30 , the orientation, including the spatial position, and the dip angle (i.e., the angle that the front surface of the mobile electronic apparatus  100  is facing relative to the horizontal line), and the horizontal height of the mobile electronic apparatus  100  may be determined. 
     The GPS device  40  is responsible for providing the positioning function. Specifically, the GPS device  40  may provide the 2D or 3D location (e.g., longitude and latitude information) of the mobile electronic apparatus  100  through communications with one or more satellites. 
     The controller  50  may be a general-purpose processor, Micro-Control Unit (MCU), Digital Signal Processor (DSP), Application Processor (AP), or any combination thereof, which includes various circuits for providing the function of data and image processing/computing, receiving image data from the image acquisition device  10 , receiving detection result from the multi-axis sensing device  30  and the GPS device  40 , and storing and retrieving data to and from the storage device  60 . In particular, the controller  50  coordinates the image acquisition device  10 , the display device  20 , the multi-axis sensing device  30 , the GSP device  40 , and the storage device  60  for performing the method for preventing a person from taking a dangerous selfie. 
     As will be appreciated by persons skilled in the art, the circuits in the controller  50  will typically comprise transistors that are configured in such a way as to control the operation of the circuitry in accordance with the functions and operations described herein. As will be further appreciated, the specific structure or interconnections of the transistors will typically be determined by a compiler, such as a Register Transfer Language (RTL) compiler. RTL compilers may be operated by a processor upon scripts that closely resemble assembly language code, to compile the script into a form that is used for the layout or fabrication of the ultimate circuitry. Indeed, RTL is well known for its role and use in the facilitation of the design process of electronic and digital systems. 
     The storage device  60  is a non-transitory computer-readable storage medium, including a memory, such as a FLASH memory or a Non-volatile Random Access Memory (NVRAM), or a magnetic storage device, such as a hard disk or a magnetic tape, or an optical disc, or any combination thereof for storing image data and instructions or program code of communication protocols, applications, and/or the method for preventing a person from taking a dangerous selfie. 
     The I/O device  60  may include one or more buttons, a keyboard, a mouse, a touch pad, a microphone, a speaker, and/or a light device, etc., serving as the Man-Machine Interface (MMI) for receiving user inputs and/or outputting prompt/feedback signals. 
     It should be understood that the components described in the embodiment of  FIG. 1  are for illustrative purposes only and are not intended to limit the scope of the application. For example, the mobile electronic apparatus  100  may include additional components, such as an Input/Output (I/O) device, a power supply, and/or a wireless communication device. The I/O device may include one or more buttons, a keyboard, a mouse, a touch pad, a microphone, a speaker, and/or a light device, etc., serving as the Man-Machine Interface (MMI) for receiving user inputs and/or outputting prompt/feedback signals. The power supply may be a mobile/replaceable battery providing power to all the other components of the mobile electronic apparatus  100 . The wireless communication device may provide the function of wireless communications to receive wireless signals (e.g., a wireless signal for controlling the image acquisition device  10  to capture image, a broadcast signal indicating that the current environment is dangerous), using a wireless technology, such as the Bluetooth technology, Wireless-Fidelity (WiFi) technology, Global System for Mobile communications (GSM) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for Global Evolution (EDGE) technology, Wideband Code Division Multiple Access (WCDMA) technology, Code Division Multiple Access 2000 (CDMA-2000) technology, Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, Worldwide Interoperability for Microwave Access (WiMAX) technology, Long Term Evolution (LTE) technology, Time-Division LTE (TD-LTE) technology, and LTE-Advanced (LTE-A) technology, etc. 
       FIG. 2  is a flow chart illustrating the method for preventing a person from taking a dangerous selfie according to an embodiment of the application. In this embodiment, the method is applied to a mobile electronic apparatus capable of taking pictures, such as the mobile electronic apparatus  100 , which at least includes an image acquisition device (e.g., image acquisition device  10 ) disposed on a surface (e.g., the front surface or back surface of the mobile electronic apparatus  100 ), and a multi-axis sensing device (e.g., the multi-axis sensing device  30 ). 
     To further clarify, the method may be implemented as a software module (e.g., an APP) consisting of program code which may be loaded and executed by a controller (e.g., the controller  50 ) of the mobile electronic apparatus. 
     To begin with, the mobile electronic apparatus uses the image acquisition device operating in the shooting mode to capture an image of a person in a background (step S 210 ). In one embodiment, the mobile electronic apparatus may be a smartphone or a panel PC, the image acquisition device may refer to the front camera, and the shooting mode may refer to the selfie mode. In another embodiment, the mobile electronic apparatus may be a hand-held image or video camera, in which the screen may be operable to be revolved to face the same direction as the camera does. 
     Next, the mobile electronic apparatus uses the multi-axis sensing device to detect the orientation information of the mobile electronic apparatus (step S 220 ). Specifically, the movements (e.g., a shift or rotation) of the mobile electronic apparatus cause changes in the orientation of the mobile electronic apparatus, wherein the orientation may be construed as the result of the mobile electronic apparatus rotating over the z-axis (e.g., the vertical axis pointing to the earth&#39;s core), y-axis (e.g., the eastern axis pointing to the geographical east), and x-axis (e.g., the northern axis pointing to the geographical north) in a coordinate system (e.g., the North East Down (NED) system). The rotation angle over the z-axis may be defined as the yaw angle ψ, the rotation angle over the y-axis may be defined as the pitch angle θ, and the rotation angle over the x-axis may be defined as the roll angle ϕ. The yaw angle ψ, the pitch angle θ, and the roll angle ϕ may be determined according to the acceleration, the changes in the magnetic field, and the angular velocity detected by the multi-axis sensing device, and may be further used to determine the orientation, including the spatial position and the dip angle, of the mobile electronic apparatus. Please note that the detailed descriptions of the orientation determination are omitted herein since they are beyond the scope of the application. 
     Subsequent to step S 220 , the mobile electronic apparatus determines whether the person is in a potentially dangerous environment according to the orientation information detected by the multi-axis sensing device and the image captured by the image acquisition device (step S 230 ). The potentially dangerous environment may include a cliff, a seashore, or the edge of a high spot in a building. The details of step S 230  will be described later in  FIGS. 5 and 6A-6D . 
     After that, the mobile electronic apparatus enables the image acquisition device to suspend or exit the shooting mode when the person is in the potentially dangerous environment (step S 240 ). The suspension or exit of the shooting mode may prevent the person from taking selfies, by enabling the image acquisition device to enter the protection mode, or by suspending/deactivating the image acquisition device. Taking the mobile electronic apparatus being a smartphone as an example, the suspension or exit of the shooting mode may include deactivating the image acquisition device and returning the smartphone to the desktop view. 
     Subsequent to step  230 , if it is determined that the person is not in a potentially dangerous environment, no action is performed and the method ends. 
       FIGS. 3A and 3B  show a flow chart illustrating the method for preventing a person from taking a dangerous selfie according to another embodiment of the application. In this embodiment, the method is applied to a mobile electronic apparatus capable of taking pictures, such as the mobile electronic apparatus  100 , which at least includes an image acquisition device (e.g., image acquisition device  10 ) disposed on a surface (e.g., the front surface or back surface of the mobile electronic apparatus  100 ), and a multi-axis sensing device (e.g., the multi-axis sensing device  30 ). 
     To further clarify, the method may be implemented as a software module (e.g., an APP) consisting of program code which may be loaded and executed by a controller (e.g., the controller  50 ) of the mobile electronic apparatus. 
     To begin with, the mobile electronic apparatus determines whether the image acquisition device has entered the shooting mode (step S 310 ). In one embodiment, the mobile electronic apparatus is a smartphone or panel PC, and it may determine whether the image acquisition device has entered the shooting mode by checking if the front camera or back camera is activated or not. Generally speaking, the shooting mode may also be referred to as the selfie mode when the front camera is activated. Alternatively, when the back camera is activated, it may also be used for taking selfies with the use of an assistive device (e.g., a shutter remote control). In another embodiment, the mobile electronic apparatus is a hand-held image or video camera with a revolvable screen, and it may determine whether the image acquisition device has entered the shooting mode by checking if the revolvable screen is manually switched to face the same direction as the camera does. 
     Subsequent to step S 310 , if the image acquisition device has entered the shooting mode, the mobile electronic apparatus determines its orientation according to the detection result obtained from the multi-axis sensing device (step S 320 ). The detailed description regarding the orientation information of the mobile electronic apparatus is similar to step S 220  in the embodiment of  FIG. 2 , and thus, it is omitted herein for brevity. 
     Subsequent to step  310 , if the image acquisition device has not entered the shooting mode, no action is performed and the method ends. 
     Subsequent to step  320 , the mobile electronic apparatus determines whether its orientation indicates that the surface on which the image acquisition device is disposed tilts down at a dip angle (i.e., the surface is facing a predetermined direction at a dip angle) (step S 330 ). For example, the mobile electronic apparatus may be a smartphone and the surface may be the front surface where the screen is disposed. In a preferred embodiment, the surface tilting down at a dip angle may suggest that the person (e.g., the user of the mobile electronic apparatus) is taking a selfie.  FIG. 4  is a schematic diagram illustrating an exemplary orientation of the mobile electronic apparatus. As shown in  FIG. 4 , the mobile electronic apparatus is a smartphone, and the dip angle is defined using the horizontal line (denoted as h) as the reference. Specifically, the dip angle refers to the angle (denoted as θ) that the screen (i.e., the front surface) of the smartphone is facing (denoted with the axis p) relative to the horizontal line. 
     Subsequent to step S 330 , if the surface on which the image acquisition device is disposed does not tilt down at a dip angle, the method ends. 
     Subsequent to step S 330 , if the surface on which the image acquisition device is disposed tilts down at a dip angle, the mobile electronic apparatus determines whether the person is in a potentially dangerous environment (e.g., a cliff, or the edge of a high spot in a building) according to the orientation information detected by the multi-axis sensing device and the image captured by the image acquisition device (step S 340 ). The details of step S 340  will be described later in  FIGS. 5 and 6A ˜ 6 D. 
     Subsequent to step S 340 , if the person is in a potentially dangerous environment, the mobile electronic apparatus enables the image acquisition device to suspend or exit the shooting mode (step S 350 ), and the method ends. The suspension or exit of the shooting mode may prevent the person from taking selfies, by enabling the image acquisition device to enter the protection mode, or by suspending/deactivating the image acquisition device. Taking the mobile electronic apparatus being a smartphone as an example, the suspension or exit of the shooting mode may include deactivating the image acquisition device and returning the smartphone to the desktop view. 
     Subsequent to step  340 , if the person is not in a potentially dangerous environment, no action is performed and the method ends. 
     In another embodiment, a new step may be included subsequent to step S 350  in  FIG. 3B , wherein the new step is to ignore any wireless signal requesting control over the image acquisition device, so as to prevent the person from taking a selfie through wireless access. 
     In another embodiment, a new step may be inserted between steps S 330  and S 340  in  FIG. 3B , wherein the new step is to identify if a human face appears in the image, and if so, the method proceeds to step S 340 , and if not, the method ends. That is, the step of human face identification is performed to further confirm if the person is really taking a selfie. 
     It should be understood that both the new step of ignoring wireless control signals and the new step of human face identification may be added to the embodiment of  FIGS. 3A and 3B . 
       FIG. 5  is a schematic diagram illustrating the determination of whether the person in the image is in a potentially dangerous environment according to an embodiment of the application. Firstly, the spatial position and the dip angle of the mobile electronic apparatus are first determined based on the detection result obtained from the multi-axis sensing device. Secondly, the skyline and earth-line in the image are determined according to the spatial position and the dip angle. Thirdly, the change in height of a background object in the image, which is the result of movement of the mobile electronic apparatus, is analyzed. Lastly, the distance from the background object to the mobile electronic apparatus is calculated according to the information regarding the change in height of the background object in the image and the movement of the mobile electronic apparatus. 
     In this embodiment, the height of the background object (e.g., a tree) is denoted as H, and the mobile electronic apparatus is depicted as a hand-held image camera. As shown in  FIG. 5 , before the mobile electronic apparatus is moved, the distance from the background object to the camera is denoted as L, the distance from the camera to the formatted image is denoted as q, and the height of the background object in the image is denoted as n. After the mobile electronic apparatus is moved to the right horizontally with a distance l, the distance from the background object to the camera becomes L′, and the height of the background object in the image becomes n′. 
     According to the lens formula, the lens magnification ratio M may be represented as 
               M   =       n   N     =     q   L         ,         
and the distance L may be derived from this mathematical relation, as follows.
 
             n   =       q   L     ×   N                   n   ′     =         q     L   ′       ⁢   N     =       q     L   +   1       ⁢   N                     n     n   ′       =         L   +   1     L     =     1   -     l   L                     L   =     l     1   -     n     n   ′                 
The distance l may be obtained from the detection result provided by the multi-axis sensing device, and the image heights n and n′ may be obtained from the number of pixels of the background object in the image. Accordingly, the distance L may be calculated.
 
     Likewise, the distance D from the person (assuming there is a person in front of the camera) to the camera may be determined. Subsequently, it may be determined whether the distance from the background object to the person is greater than a predetermined threshold according to the distances L and D. If the distance from the background object to the person is greater than the predetermined threshold, it may be determined that the person is in a potentially dangerous environment. In one embodiment, the predetermined threshold may be 10 meters. 
       FIGS. 6A to 6D  are schematic diagrams illustrating the determination of whether the person in the image is in a potentially dangerous environment according to an embodiment of the application. Firstly, the spatial position and the dip angle of the mobile electronic apparatus are first determined based on the detection result obtained from the multi-axis sensing device. Secondly, the skyline and earth-line in the image are determined according to the spatial position and the dip angle. Lastly, the variations of grey scales of the pixels along the skyline or earth-line are analyzed. 
       FIG. 6A  depicts an exemplary image captured by the image acquisition device. As shown in  FIG. 6A , the earth-line k in the image is determined.  FIG. 6B  depicts the distribution of the variations of grey scales of the pixels along the earth-line k. As shown in  FIG. 6B , grey scales fluctuate intensely, wherein each variation of grey scales may represent a common border of objects in the background, and a higher variation may indicate a more complicated composition of objects in the background. Generally, an image taken from a higher ground may cover more objects in the background, and thus, may have more drastic variations of grey scales. Therefore, when the variations of grey scales of the pixels along the earth-line are drastic, it may be determined that the image was taken from a high ground and that the person is in a potentially dangerous environment. 
     Specifically, within the pixels 0˜100, there are 28 crests and troughs formed by the grey-scale variation over 50. Within the pixels 100˜200, there are 14 crests and troughs formed by the grey-scale variation over 50. Within the pixels 200˜300, there are 13 crests and troughs formed by the grey-scale variation over 50. Overall, the average number of crests and troughs within every 100 pixels is greater than 5, and thus, it may be determined that the person is in a potentially dangerous environment. 
       FIG. 6C  depicts another exemplary image captured by the image acquisition device. As shown in  FIG. 6C , the earth-line m in the image is determined.  FIG. 6D  depicts the distribution of the variations of grey scales of the pixels along the earth-line m. As shown in  FIG. 6D , grey scales fluctuate less intensely, when compared to  FIG. 6B . Overall, the average number of crests and troughs within every 100 pixels is less than 5, and thus, it may be determined that the person is not in a potentially dangerous environment. 
     It should be understood that the threshold value 5 described in the embodiments of  FIGS. 6A ˜ 6 D is for illustrative purposes only and is not intended to limit the scope of the application. 
       FIGS. 7A and 7B  show a flow chart illustrating the method for preventing a person from taking a dangerous selfie according to yet another embodiment of the application. In this embodiment, the method is applied to a mobile electronic apparatus capable of taking pictures, such as the mobile electronic apparatus  100 , which at least includes an image acquisition device (e.g., image acquisition device  10 ) disposed on a surface (e.g., the front surface or back surface of the mobile electronic apparatus  100 ), and a multi-axis sensing device (e.g., the multi-axis sensing device  30 ). 
     To further clarify, the method may be implemented as a software module (e.g., an APP) consisting of program code which may be loaded and executed by a controller (e.g., the controller  50 ) of the mobile electronic apparatus. 
     To begin with, the mobile electronic apparatus determines whether the image acquisition device has entered the shooting mode (step S 710 ). In one embodiment, the mobile electronic apparatus is a smartphone or panel PC, and it may determine whether the image acquisition device has entered the shooting mode by checking if the front camera or back camera is activated or not. Generally speaking, the shooting mode may also be referred to as the selfie mode when the front camera is activated. Alternatively, when the back camera is activated, it may also be used for taking selfies with the use of an assistive device (e.g., a shutter remote control). In another embodiment, the mobile electronic apparatus is a hand-held image or video camera with a revolvable screen, and it may determine whether the image acquisition device has entered the shooting mode by checking if the revolvable screen is manually switched to face the same direction as the camera does. 
     Subsequent to step S 710 , if the image acquisition device has entered the shooting mode, the mobile electronic apparatus uses the GPS device to obtain its location (step S 720 ). Otherwise, if the image acquisition device has not entered the shooting mode, the method ends. 
     Subsequent to step S 720 , the mobile electronic apparatus determines the altitude corresponding to its location according to the geographic mapping information (step S 730 ), and then uses the multi-axis sensing device (e.g., the altitude sensor within the multi-axis sensing device) to detect its horizontal height (step S 740 ). 
     Subsequent to step S 730 , the mobile electronic apparatus determines whether the difference between its horizontal height and the altitude is greater than a predetermined threshold (step S 750 ), and if not, the method ends. In one embodiment, the predetermined threshold may be  10  meters but not limited thereto. 
     Subsequent to step S 750 , if the difference is greater than a predetermined threshold, it may be determined that the person in the image is in a building at that location, and the mobile electronic apparatus uses the multi-axis sensing device to detect the orientation information (step S 760 ). 
     Subsequent to step S 760 , the mobile electronic apparatus determines whether the orientation information indicates that a specific surface (e.g., the surface on which the image acquisition device is disposed) of the mobile electronic apparatus tilts down at a dip angle (i.e., the surface is facing a predetermined direction at a dip angle) (step S 770 ). For example, the mobile electronic apparatus may be a smartphone and the surface may be the front surface where the screen is disposed. In a preferred embodiment, the surface tilting down at a dip angle may suggest that the person (e.g., the user of the mobile electronic apparatus) is taking a selfie, as shown in  FIG. 4 . 
     Subsequent to step S 770 , if the surface does not tilt down at a dip angle, the method ends. 
     Subsequent to step S 770 , if the surface tilts down at a dip angle, the mobile electronic apparatus determines whether the person is in a potentially dangerous environment (e.g., a cliff, or the edge of a high spot of a building) according to the orientation information detected by the multi-axis sensing device and the image captured by the image acquisition device (step S 780 ). The reference regarding detailed description of step S 780  may be made to the embodiments of  FIGS. 5 and 6A ˜ 6 D as mentioned above. 
     Subsequent to step S 780 , if the person is in a potentially dangerous environment, the mobile electronic apparatus enables the image acquisition device to suspend or exit the shooting mode (step S 790 ), and the method ends. The suspension or exit of the shooting mode may prevent the person from taking selfies, by enabling the image acquisition device to enter the protection mode, or by suspending/deactivating the image acquisition device. Taking the mobile electronic apparatus being a smartphone as an example, the suspension or exit of the shooting mode may include deactivating the image acquisition device and returning the smartphone to the desktop view. 
     Subsequent to step  780 , if the person is not in a potentially dangerous environment, the method ends. 
     In another embodiment, a wireless station may be disposed in a certain area (e.g., a high-floor observation deck) within a building to broadcast a wireless signal indicating that the coverage area of the wireless signal is dangerous, and a new step may be included subsequent to the ‘YES’ branch of step S 780  in  FIG. 7B , wherein the new step is performed to check whether such a broadcast signal has been received, and if so, step S 790  is performed. Otherwise, if such a broadcast signal has not been received, it may suggest that the person is in a safe area (e.g., indoors) on the high floor of the building, and step S 790  may not be performed. 
     In another embodiment, a new step may be included subsequent to step S 790  in  FIG. 7B , wherein the new step is to ignore any wireless signal requesting control over the image acquisition device, so as to prevent the person from taking a selfie through wireless access. 
     In another embodiment, a new step may be inserted between steps S 770  and S 780  in  FIG. 7B , wherein the new step is to identify if a human face appears in the image, and if so, the method proceeds to step S 780 , and if not, the method ends. That is, the step of human face identification is performed to further confirm if the person is really taking a selfie. 
     It should be understood that both the new step of ignoring wireless control signals and the new step of human face identification may be added to the embodiment of  FIGS. 7A and 7B . 
     In view of the forgoing embodiments, it will be appreciated that the present application may prevent the user of a mobile electronic apparatus from taking dangerous selfies, by detecting whether the user in the captured image is in a potentially dangerous environment according to the image acquisition device, the multi-axis sensing device, and/or the positioning device of the mobile electronic apparatus, and enabling the image acquisition device to suspend or exit the shooting mode. Advantageously, accidents caused by taking dangerous selfies may be avoided. 
     While the application has been described by way of example and in terms of preferred embodiment, it should be understood that the application cannot be limited thereto. Those who are skilled in this technology can still make various alterations and modifications without departing from the scope and spirit of this application. Therefore, the scope of the present application shall be defined and protected by the following claims and their equivalents. 
     Note that use of ordinal terms such as “first”, “second”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of the method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having the same name (except for use of ordinal terms), to distinguish the claim elements.