Patent Publication Number: US-2018033177-A1

Title: Method for image display and electronic device supporting the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims priority under 35 U.S.C. §119 to a Korean patent application filed on Aug. 1, 2016 in the Korean Intellectual Property Office and assigned Serial number 10-2016-0097833, the disclosure of which is incorporated by reference herein in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates generally to an image display technology based on a head mounted display device. 
     BACKGROUND 
     Various shapes of image devices are being suggested as image processing technologies rapidly develop. For example, a head mounted display (HMD) device that is a wearable image display device mountable on the body may display an image in the field of view of a user. 
     The HMD device may display a large-screen, high-magnification image through an internal optical device based on an image signal provided from an external digital device or an internal device. In addition, the HMD device may display a stereoscopic virtual reality (VR) image and may be used in various fields such as an education field, a military field, a medical field, or an industry field. 
     Since the HMD device is operated while being mounted on a facial area of the user, the field of view of the user may be restricted within an inner area of the HMD device. In this case, the user that views an image through the HMD device may fail to perceive a peripheral environment, thus colliding with a peripheral object (e.g., animals, things, human bodies, or the like). 
     SUMMARY 
     Example aspects of the present disclosure address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an example aspect of the present disclosure provides an image display method that allows a user wearing an HMD device to perceive an environment on a real space based on an image taken from an object adjacent to the HMD device and an electronic device supporting the same. 
     In accordance with an example aspect of the present disclosure, a head mounted electronic device may include a display configured to display a virtual reality (VR) image in left-eye and right-eye lens areas, a camera module configured to photograph an image, and a processor configured to detect at least one object existing within a photographing range of the camera module based on the photographed image of the camera module. 
     According to an example embodiment, the processor may switch the VR image into the photographed image or into an augmented reality (AR) image including at least part of the photographed image if at least one object exists within a first area, the first area comprising an area from the camera module to a point spaced apart from the camera module by a first distance within the photographing range. 
     Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and attendant advantages of the present disclosure will be more apparent and readily appreciated from the following detailed description, taken in conjunction with the accompanying drawings, in which like reference numerals refer to like elements, and wherein: 
         FIG. 1  is a diagram illustrating an example head mounted display device according to an example embodiment; 
         FIG. 2  is a diagram illustrating an example of an operation of the head mounted display device according to an example embodiment; 
         FIG. 3  is a diagram illustrating an example of a real space in which the head mounted display device is operated according to an example embodiment; 
         FIG. 4  is a diagram illustrating an example configuration of an electronic device according to an example embodiment; 
         FIG. 5A  is a diagram illustrating an example first embodiment in which an object exists within a first area; 
         FIG. 5B  is a diagram illustrating an example of image switching according to the first embodiment; 
         FIG. 5C  is a diagram illustrating another example of image switching according to the first embodiment; 
         FIG. 5D  is a diagram illustrating another example of image switching according to the first embodiment; 
         FIG. 6A  is a diagram illustrating an example second embodiment in which an object exists within a second area; 
         FIG. 6B  is a diagrams illustrating an example of image switching according to the second embodiment; 
         FIG. 7A  is a diagram illustrating an example third embodiment in which an object exists within a photographing range of a camera module; 
         FIG. 7B  is a diagram illustrating an example of image switching according to the third embodiment; 
         FIG. 8  is a flowchart illustrating an example image display method of the electronic device according to an example embodiment; and 
         FIG. 9  is a flowchart illustrating an example image display method of the electronic device according to another example embodiment. 
     
    
    
     Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. 
     DETAILED DESCRIPTION 
     Various example embodiments of the present disclosure may be described with reference to accompanying drawings. Accordingly, those of ordinary skill in the art will recognize that modifications, equivalents, and/or alternatives of the various embodiments described herein can be variously made without departing from the scope and spirit of the present disclosure. With regard to description of drawings, similar elements may be marked by similar reference numerals. 
     In the disclosure disclosed herein, the expressions “have”, “may have”, “include” and “comprise”, or “may include” and “may comprise” used herein indicate existence of corresponding features (e.g., elements such as numeric values, functions, operations, or components) but do not exclude presence of additional features. 
     In the disclosure disclosed herein, the expressions “A or B”, “at least one of A or/and B”, or “one or more of A or/and B”, and the like used herein may include any and all combinations of one or more of the associated listed items. For example, the term “A or B”, “at least one of A and B”, or “at least one of A or B” may refer to all of the case (1) where at least one A is included, the case (2) where at least one B is included, or the case (3) where both of at least one A and at least one B are included. 
     The terms, such as “first”, “second”, and the like used in this disclosure may be used to refer to various elements regardless of the order and/or the priority and to distinguish the relevant elements from other elements, but do not limit the elements. For example, “a first user device” and “a second user device” indicate different user devices regardless of the order or priority. For example, without departing the scope of the present disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. 
     It will be understood that when an element (e.g., a first element) is referred to as being “(operatively or communicatively) coupled with/to” or “connected to” another element (e.g., a second element), it may be directly coupled with/to or connected to the other element or an intervening element (e.g., a third element) may be present. On the other hand, when an element (e.g., a first element) is referred to as being “directly coupled with/to” or “directly connected to” another element (e.g., a second element), it should be understood that there are no intervening element (e.g., a third element). 
     According to the situation, the expression “configured to” used herein may be used interchangeably with, for example, the expression “suitable for”, “having the capacity to”, “designed to”, “adapted to”, “made to”, or “capable of”. The term “configured to” must not mean only “specifically designed to” in hardware. Instead, the expression “a device configured to” may refer to a situation in which the device is “capable of” operating together with another device or other components. For example, a “processor configured to perform A, B, and C” may refer to a dedicated processor (e.g., an embedded processor) for performing a corresponding operation or a generic-purpose processor (e.g., a central processing unit (CPU) or an application processor) which may perform corresponding operations by executing one or more software programs which are stored in a memory device. 
     Terms used in this disclosure are used to describe specified embodiments of the present disclosure and are not intended to limit the scope of the present disclosure. The terms of a singular form may include plural forms unless otherwise specified. All the terms used herein, which include technical or scientific terms, may have the same meaning that is generally understood by a person skilled in the art. It will be further understood that terms, which are defined in a dictionary and commonly used, should also be interpreted as is customary in the relevant related art and not in an idealized or overly formal unless expressly so defined herein in various embodiments of the present disclosure. In some cases, even if terms are terms which are defined in the disclosure, they may not be interpreted to exclude embodiments of the present disclosure. 
     An electronic device according to various embodiments of the present disclosure may include at least one of a smartphone, a tablet personal computer (PC), a mobile phone, a video telephone, an electronic book reader, a personal digital assistant (PDA), a portable multimedia player (PMP), or a smart camera, or the like, but is not limited thereto. 
     According to various embodiments, the electronic device may be one of the above-described devices or a combination thereof. An electronic device according to an embodiment may be a flexible electronic device. Furthermore, an electronic device according to an embodiment may not be limited to the above-described electronic devices and may include other electronic devices and new electronic devices according to the development of technologies. 
     Hereinafter, electronic devices according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. The term “user” used herein may refer to a person who uses an electronic device (or a head mounted display device) or may refer to a device (e.g., an artificial intelligence electronic device). 
     An electronic device described across the disclosure may be operated while being mounted on a head mounted display (HMD) device and may be configured to be removable from the HMD device. Alternatively, the electronic device may include the HMD device or may be physically or operatively integrated with the HMD device. Below, an example embodiment in which an electronic device is mounted and operated on an HMD device will be described. 
       FIG. 1  is a diagram illustrating an example head mounted display device according to an example embodiment. 
     Referring to  FIG. 1 , an HMD device  200  may include a main frame  210 , a support member  220 , a front frame  230 , or a mounting member  240 . An electronic device  100  may be included as an element of the HMD device  200 . 
     The main frame  210  may form a body of the HMD device  200  and may also accommodate at least some of elements associated with performing a function of the HMD device  200 . The main frame  210  may be supported by the support member  220  on a face (e.g., a facial area) of the user. For this reason, the main frame  210  may be formed of a lightweight material (e.g., plastic). 
     The main frame  210  may include a positioning member  211  and/or an input member  213 . The positioning member  211  may control a front or rear movement of the front frame  230 . For example, if the user operates the positioning member  211 , at least part of the front frame  230  may be inserted into the main frame  210  or may protrude to the outside from the main frame  210 . As such, the electronic device  100  mounted on the front frame  230  may come close to a user&#39;s face or may be spaced apart from the user&#39;s face. The user may adjust a location of the electronic device  100  through the positioning member  211  to make a sight environment suitable for the user. In various embodiments, the positioning member  211  may include, for example, a wheel, a dial, or the like. 
     The input member  213  may include various input circuitry and allow a function of the electronic device  100  to operate in response to, for example, a user input (e.g., a touch, a press, a drag, or the like). In this regard, the user may allow a graphic user interface (GUI) to be displayed on a screen displayed in sight, by using the input member  213 . The user may control a settings item associated with image playback, such as an audio volume of the electronic device  100 , by operating the input member  213  such that an input signal is applied to at least one object (e.g., a settings menu) included in the GUI. In various embodiments, the input member  213  may include at least one of a touch pad, a physical button, a joystick, and a wheel. 
     The main frame  210  may further include a connector (not illustrated) for communicating with the electronic device  100 . The connector may perform a role of an input/output interface between the HMD device  200  and the electronic device  100 . For example, an input applied to the input member  213  (or a signal input to the GUI) may be transferred to the electronic device  100  through the connector. In various embodiments, the connector may include a USB connector that is connectable to a USB port of the electronic device  100 . Also, in various embodiments, the connector may be implemented with a coupling member  231  itself or may be disposed in a partial area of the coupling member  231 . 
     The support member  220  may support the main frame  210  on the user&#39;s face (e.g., a facial area). The support member  220  may be coupled to one side surface (e.g., a rear surface) of the main frame  210  or may be integrally formed with the main frame  210 . The support member  220  may have a structure corresponding to a facial curve of a human, thus closely making contact with the user&#39;s face. In various embodiments, at least a partial area of the support member  220  may include a cushion material for reducing physical friction with the user&#39;s face, physical impact, or the like. 
     The front frame  230  may provide an area for mounting (or integration with or accommodating) the electronic device  100 . In this regard, a shape of the front frame  230  may correspond to the size or area of the electronic device  100 . In an embodiment, the front frame  230  may include at least one coupling member  231  for fixing the electronic device  100 . At least part of a lens assembly  233  disposed inside the front frame  230  (or the main frame  210 ) may be exposed through at least a partial area of the front frame  230 . Accordingly, the user that wears the HMD device  200  may view at least a partial area (e.g., a front display area) of the electronic device  100  through the lens assembly  233 . 
     The mounting member  240  (e.g., a band) may fix the main frame  210  on the user&#39;s face upon wearing the HMD device  200 . Opposite ends of the mounting member  240  may have a hook structure and may be connected with opposite ends of the main frame  210 . The mounting member  240  may include, for example, an elastic material or may include a member (e.g., a buckle, a Velcro, a magnet, or the like) for adjusting a length. Accordingly, the mounting member  240  may stably surround a head area of the user and may fix a location of the main frame  210  while supporting a weight of the main frame  210 . In various embodiments, the mounting member  240  may be replaced with eyeglass temples, a helmet, straps, or the like. 
     The electronic device  100  may be mounted on the front frame  230  based on the coupling member  231  and may interact with the HMD device  200 . For example, an image displayed in a display area of the electronic device  100  may be displayed in the field of view of the user of the HMD device  200  through the lens assembly  233 . 
     In various embodiments, the HMD device  200  may further include a cover member  250 . The cover member  250  may assist in preventing and/or reducing the likelihood of separation of the electronic device  100  and may also protect the electronic device  100  from external impact. With regard to performing a function of the electronic device  100  (e.g., operating a camera  130 ), a partial area (e.g., an area corresponding to a location of the camera  130 ) of the cover member  250  may include, for example, an opening  251 . 
       FIG. 2  is a diagram illustrating an example of an operation of a head mounted display device according to an example embodiment. 
     Referring to  FIGS. 1 and 2 , the HMD device  200  on which the electronic device  100  is mounted may display a screen in the field of view of the user. For example, the electronic device  100  mounted on the HMD device  200  may display an image in a display area, and the image may be displayed in a screen (e.g., a screen viewed through the lens assembly  233 ) that is displayed in the field of view of the user through the HMD device  200 . In this operation, the electronic device  100  may execute a normal function (e.g., a function of displaying one image in a display area) or a virtual reality (VR) function (e.g., a function of displaying one image in a display area so as to be separated into a left-eye area and a right-eye area). In the case where the electronic device  100  displays an image based on the VR function, the user may view a VR image  10  through the lens assembly  233  of the HMD device  200 . In various embodiments, to prevent distortion of an image due to lens included in the lens assembly  233 , the VR function may inversely distort a two-dimensional image depending on a characteristic of the lens. 
       FIG. 3  is a diagram illustrating an example of a real space in which a head mounted display device according to an example embodiment is operated. 
     As illustrated in  FIG. 3 , the user that wears the HMD device  200  may be near or neighbor various objects (e.g., an animal  1 , objects  2  and  3 , a human body (not illustrated), and the like) in a real space. Alternatively, in the case where the user moves with regard to operating the HMD device  200  (e.g., executing a game through the VR image  10 ), the user may approach the objects. 
     Since only the VR image  10  is displayed in the field of view of the user that wears the HMD device  200 , the user may fail to perceive a neighboring or approaching object or may fail to grasp an exact location of the object. In this case, there may be a risk of collision between the user wearing the HMD device  200  and the object existing within the real space. The collision may cause accidents, such as user injury and object damage, in addition to a simple physical contact. In this regard, the electronic device  100  according to an embodiment may detect an object existing within a specified distance from the HMD device  200  (or the user wearing the HMD device  200 ). If the object is detected, the electronic device  100  may switch an image displayed in the display area into an image associated with the object, thus providing the user with a notification associated with the object. 
       FIG. 4  is a diagram illustrating an example configuration of an electronic device according to an example embodiment. 
     Referring to  FIG. 4 , the electronic device  100  may include a memory  110 , a display  120 , a camera module (e.g., including camera circuitry)  130 , a processor (e.g., including processing circuitry)  140 , an input/output interface (e.g., including input/output circuitry)  150 , and/or a communication interface (e.g., including communication circuitry)  160 . In an embodiment, the electronic device  100  may not include at least one of the above-described elements or may further include any other element(s). In various embodiments, at least some of the above-described elements may be included as elements of the HMD device  200 , or the electronic device  100  including the above-described elements may be included as an element of the HMD device  200 . 
     The memory  110  may include a volatile and/or nonvolatile memory. For example, the memory  110  may store instructions or data associated with at least one other element of the electronic device  100 . In various embodiments, the memory  110  may store an application program, and the application program may include, for example, at least one image data to be displayed through the display  120 . 
     The display  120  may display various content (e.g., texts, images, video, icons, symbols, or the like). For example, the display  120  may display content corresponding to the at least one image data included in the application program. In various embodiments, in the case where the electronic device  100  operates the VR function, the display  120  may separate and display one image into two images corresponding to a left eye and a right eye of the user, respectively. In various embodiments, the display  120  may include a liquid crystal display (LCD), a light-emitting diode (LED) display, an organic LED (OLED) display, a microelectromechanical systems (MEMS) display, or an electronic paper display, or the like, but is not limited thereto. 
     The camera module  130  may include various camera circuitry and photograph a still image or a video. For example, if the electronic device  100  is mounted on the HMD device  200 , the camera module  130  may photograph an image of an area in front of the HMD device  200 . In an embodiment, after the electronic device  100  is mounted on the HMD device  200 , the camera module  130  may be activated as soon as the HMD device  200  is driven or after a specified time elapses from a point in time when the HMD device  200  is driven. In various embodiments, the camera module  130  may be activated from a point in time when the electronic device  100  is mounted on the HMD device  200 . Alternatively, the camera module  130  may be activated from a point in time when the user wears the HMD device  200 . 
     In various embodiments, the camera module  130  may include various camera circuitry, such as, for example, and without limitation, at least one depth camera (e.g., a time of flight (TOF) manner or a structure light manner) and/or a color camera (e.g., an RGB camera). Also, the camera module  130  may further include at least one sensor (e.g., a proximity sensor) or light source (e.g., an LED array) with regard to executing a function. In various embodiments, the at least one sensor may be implemented with a module that is independent of the camera module  130  and may sense an area in front of the HMD device  200 . For example, a sensor (e.g., proximity sensor) module may sense an object by emitting infrared rays (or ultrasonic waves) to an area in front of the HMD device  200  and receiving infrared rays (or ultrasonic waves) reflected from the object. In this case, the camera module  130  may be activated from a point in time when at least one object is sensed by the sensor module. 
     The processor  140  may include various processing circuitry and perform data processing or an operation associated with control or communication of at least one other element of the electronic device  100 . For example, the processor  140  may obtain data of an image photographed by the camera module  130  and may detect an object existing within a photographing range of the camera module  130  based on the obtained image data. In this operation, the processor  140  may exclude an external device (e.g., a joystick paired with the HMD device  200 ) associated with the HMD device  200  from a detection target. In this regard, the processor  140  may store image data of at least part of the external device in the memory  110  upon setting pairing between the HMD device  200  and the external device. In an embodiment, the processor  140  may compare image data of at least one object detected within a photographing range of the camera module  130  with the image data stored in the memory  110 . If the comparison result indicates that image data of a specific object coincides with the image data stored in the memory  110  by a specified numeric value or more, the processor  140  may determine whether the electronic device  100  or the HMD device  200  interacts with the specified object (or whether specified data are transmitted and received between the specific object and the electronic device  100  or the HMD device  200 ). The processor  140  may identify an object, which corresponds to the image data stored in the memory  110  and interacts with the electronic device  100  or the HMD device  200 , as an external device paired with the HMD device  200  and may exclude the identified object from object detection targets. 
     In various embodiments, the processor  140  may exclude an object associated with the user wearing the HMD device  200  from the detection target. For example, the processor  140  may determine an object, which exists within a specified range (e.g., a range that is determined by a radius corresponding to the user&#39;s arm length) from the user wearing the HMD device  200 , as a user&#39;s body and may exclude the determined object from the detection target. Alternatively, the processor  140  may determine an object that physically makes contact with an external device paired with the HMD device  200  as the body of the user gripping the external device and may exclude the determined object from the detection target. 
     In an embodiment, the processor  140  may calculate (determine) or detect the number of detected objects, the size of a detected object, a distance between a detected object and the HMD device  200 , a movement of a detect object, or the like. The processor  140  may control the driving of the display  120  based on the calculated or detected result. This will be more fully described below. 
     In various embodiments, the processor  140  may include various processing circuitry, such as, for example, and without limitation, at least one of a dedicated processor, a central processing unit (CPU), an application processor (AP), and a communication processor (CP). As hardware, at least part of the processor  140  may access the memory  110  to perform a function associated with an instruction stored in the memory  110 . 
     The input/output interface  150  may include various input/output circuitry and transfer a command or data from the user or another external device (e.g., the HMD device  200 ) to any other element of the electronic device  100 . Also, the input/output interface  150  may output a command or data from any other element of the electronic device  100  to the user or another external device. 
     The communication interface  160  may include various communication circuitry and establish communication between the electronic device  100  and an external device (e.g., the HMD device  200 ). For example, the communication interface  160  may support communication with the external device through wireless communication (e.g., wireless fidelity (Wi-Fi), Bluetooth, near field communication (NFC), magnetic stripe transmission (MST), or the like) or wired communication. 
       FIG. 5A  is a diagram illustrating an example first embodiment in which an object exists within a first area, and  FIGS. 5B, 5C and 5D  are diagrams illustrating various examples of image switching according to the example first embodiment. 
     Referring to  FIG. 5A , the user may operate the HMD device  200  on which the electronic device  100  is mounted in any real space. The camera module  130  installed in the electronic device  100  may be activated if a specific time elapses from a point in time when the HMD device  200  is driven. In various embodiments, the camera module  130  may be activated from a point in time when the electronic device  100  is mounted on the HMD device  200  or from a point in time when the user wears the HMD device  200 . 
     At a point in time when the camera module  130  is activated, the HMD device  200  may be in a state where an image (e.g., a VR image) is displayed in the field of view of the user or in a state where the HMD device  200  makes ready for displaying an image. Various embodiments that will be described below ( FIGS. 5A to 5D ,  FIGS. 6A and 6B , or  FIGS. 7A and 7B ) will be described as the HMD device  200  displays a VR image at a point in time when the camera module  130  is activated but may be identically or similarly applied to a state where the HMD device  200  makes ready for displaying the VR image. 
     The activated camera module  130  may continuously or periodically photograph an area in front of the HMD device  200 . The camera module  130  may transfer the photographed image to a processor ( 140  of  FIG. 4 ) of the electronic device  100  in real time, in the form of a batch, or in the form of a stream. The processor  140  may detect an object existing within a photographing range  131  of the camera module  130  based on the photographed image. 
     In an embodiment, in the case where at least one object (e.g., a dog  1 ) exists within the photographing range  131  of the camera module  130 , the processor  140  may calculate (determine) a distance from the HMD device  200  to the object  1 . If the calculated distance between the HMD device  200  and the object  1  is within a specified first distance “r”, the processor  140  may determine that the object  1  exists within a first area  132  that is specified as an area from the HMD device  200  to a point spaced apart therefrom by the first distance “r”. 
     In an embodiment, with regard to the at least one object  1  existing within the first area  132 , the processor  140  may switch an image displayed in the display  120  of the electronic device  100  into an image taken by the camera module  130 . In this case, as illustrated in  FIG. 5B , the VR image  10  played on a screen of the HMD device  200  may be switched into a photographed image  30  associated with an area in front of the HMD device  200  based on driving of the camera module  130 . In various embodiments, the processor  140  may control the electronic device  100  such that specified notification sound or vibration is output in switching into the photographed image  30 . Also, in various embodiments, a numeric value indicating a distance between the HMD device  200  and the object  1  existing within the first area  132  may be displayed on the photographed image  30  thus switched. 
     Referring to another embodiment, in the case where the at least one object  1  exists within the first area  132 , the processor  140  may switch an image displayed in the display  120  of the electronic device  100  into an augmented reality (AR) image. For example, the AR image may include an image in which at least part of the VR image  10  displayed on a screen of the HMD device  200  and at least part of the photographed image  30  photographed by the camera module  130  are overlaid (a picture in picture (PIP) manner). Accordingly, the AR image may include an image in which at least part of any one of the VR image  10  and the photographed image  30  is included in the other thereof. In this regard, referring to  FIG. 5C , the VR image  10  displayed in the field of view of the user wearing the HMD device  200  may be switched into an AR image  40   a  in which a photographed image of the object  1  is overlaid on the VR image  10 . In various embodiments, the processor  140  may control any other elements of the electronic device  100  such that an event such as specified notification sound or vibration is output, together with the image switching operation. 
     Referring to  FIG. 5D  according to another embodiment, in the case where the at least one object  1  exists within the first area  132 , the processor  140  may switch an AR image, a type of which is different from that of the above-described AR image. For example, the AR image of the different type may include an image in which the VR image  10  displayed on the display  120  and the photographed image  30  of the camera module  130  are in parallel with each other in the same frame (e.g., a picture out picture (POP) manner). Accordingly, an image displayed on a screen of the HMD device  200  may be switched from the VR image  10  into an AR image  40   b  in which the VR image  10  and the photographed image  30  divided to have the specified size are displayed. 
       FIG. 6A  is a diagram illustrating an example second embodiment in which an object exists within a second area, and  FIG. 6B  is a diagram illustrating an example of image switching according to the example second embodiment. 
     In  FIG. 6A , an operation of detecting, at a processor ( 140  of  FIG. 4 ) of the electronic device  100 , an object existing within the photographing range  131  of the camera module  130  and operations attended by the detecting operation may be the same as or similar to the operations described with reference to  FIG. 5A  or may correspond to the operations described with reference to  FIG. 5A . 
     In an embodiment, in the case where at least one object (e.g., a dog  1 ) exists within the photographing range  131  of the camera module  130 , the processor  140  may calculate (determine) a distance from the HMD device  200  to the object  1 . If the distance between the HMD device  200  and the object  1  exceeds the specified first distance “r” and is not greater than a third distance (e.g., a distance corresponding to a sum of the first distance “r” and a specified second distance “R”), the processor  140  may determine that the object  1  exists within a second area  133 . For example, the second area  133  may include an area from a boundary of the above-described first area ( 132  of  FIG. 5A ) to a point “P” spaced apart therefrom by the specified second distance “R”. 
     In an embodiment, in the case where the at least one object  1  exists within the second area  133 , the processor  140  may add at least one content to at least one area of an image displayed in a display ( 120  of  FIG. 4 ) of the electronic device  100 . For example, the at least one content may include an icon, an image such as a shaded silhouette or a symbol, or a text such as characters, which are associated with the object  1  existing within the second area  133 . In various embodiments, the processor  140  may control the electronic device  100  such that specified notification sound or vibration is output together with adding the content. As content is added to an image on the display  120 , as illustrated in  FIG. 6B , the VR image  10  that includes content  1   a  (e.g., an icon) associated with the object  1  may be displayed in the field of view of the user wearing the HMD device  200 . 
     In various embodiments, in the case where the object  1  existing within the second area  133  is a dynamic object, the processor  140  may allow the content  1   a  to track a location of the dynamic object on an image displayed on the display  120 . For example, the processor  140  may continuously or periodically analyze a photographed image provided from the camera module  130  in real time, in the form of a batch, or in the form of a stream to detect a direction variation of the object  1 , a size variation of the object  1 , a variation in a distance between the object  1  and the HID device  200 , or the like. If at least one variation is detected, the processor  140  may determine that the object  1  is a dynamic object. The processor  140  may track a movement of a dynamic object based on a photographed image and may adjust a location, at which the contents  1   a  is added on an image displayed in the display  120 , so as to correspond to a location movement of the dynamic object. 
       FIG. 7A  is a diagram illustrating an example third embodiment in which an object exists within a photographing range, and  FIG. 7B  is a diagram illustrating an example of image switching according to the example third embodiment. An example embodiment that will be described with reference to  FIGS. 7A and 7B  may be associated with the execution of the operations and functions assumed in the embodiment described with reference to  FIGS. 5A to 5D  or in the embodiment described with reference to  FIGS. 6A and 6B . 
     In  FIG. 7A , operations associated with activating the camera module  130  may be the same as or similar to those described with reference to  FIG. 5A . The activated camera module  130  may perform first photographing on an area in front of the HID device  200  and may transfer the photographed image to a processor ( 140  of  FIG. 4 ). 
     The processor  140  may calculate (determine) the number of objects (e.g., a dog  1 , a table  2 , and a sofa  3 ) existing within the photographing range  131  of the camera module  130 , based on the first photographed image from the camera module  130 . In an embodiment, if the calculated number of objects exceeds a specified threshold value, the processor  140  may switch an image displayed in a display ( 120  of  FIG. 4 ) into at least one pop-up window. In this case, as illustrated  FIG. 7B , the VR image  10  that is displayed in the field of view of the user wearing the HID device  200  may be switched into at least one pop-up window  20 . At least one text that is associated with a request to change a location of the HID device  200  (or a location of the user wearing the HMD device  200 ) may be included in the pop-up window  20 . However, the pop-up window  20  is not limited to  FIG. 7B  and may include various shapes, a plurality of pop-up windows, various contents, or the like. 
     In various embodiments, the processor  140  may calculate the sizes of the objects  1 ,  2 , and  3  existing within the photographing range  131  of the camera module  130  based on the first photographed image. If the size of at least one object is larger than a specified threshold size, the processor  140  may switch the displayed VR image  10  into the pop-up window  20 . In this operation, even though the calculated number of objects  1 ,  2 , and  3  does not exceed a specified threshold value, the processor  140  may switch the VR image  10  into the pop-up window  20  if at least one object exceeds a threshold size. 
     As described above, a head mounted electronic device according to various embodiments, may include a display that displays a virtual reality (VR) image in left-eye and right-eye lens areas, a camera module comprising camera circuitry configured to photographs an image, and a processor that detects at least one object existing within a photographing range of the camera module based on a photographed image photographed by the camera module. 
     According to various example embodiments, the processor may switch the VR image to the photographed image or to switch the VR image to an augmented reality (AR) image including at least part of the photographed image if at least one object exists within a first area, the first area being an area from the camera module to a point spaced apart from the camera module by a first distance within the photographing range of the camera module. 
     According to various example embodiments, the processor may add at least one content associated with the object existing within a second area to the VR image if at least one object exists within the second area, the second area being an area from a boundary of the first area to a point spaced apart from the boundary of the first area by a second distance within the photographing range of the camera module. 
     According to various example embodiments, the processor may allow tracking a location variation of a dynamic object on the VR image if the at least one object existing within the second area is a dynamic object. 
     According to various example embodiments, the processor may determine a number of objects existing within the photographing range of the camera module based on an image that is photographed by the camera module after the head mounted electronic device is driven and may switch the VR image to at least one pop-up window if the determine number of objects exceeds a specified threshold number of objects. 
     According to various example embodiments, the pop-up window may include at least one text associated with a location change of the head mounted electronic device. 
     According to various example embodiments, the camera module may be activated after a specified time elapses from a point in time when the head mounted electronic device is driven. 
     According to various example embodiments, the head mounted electronic device may include at least one coupler on which an electronic device including at least one of the camera module and the processor is mounted. 
     According to various example embodiments, the camera module may be activated from a point in time when the electronic device is mounted on the head mounted electronic device. 
     According to various example embodiments, the processor may overlay a photographed image of at least part of the object existing within the first area on at least part of the VR image upon switching the VR image to the AR image. 
     According to various example embodiments, the processor may separately display the VR image and the photographed image, each of which has a specified size, on a single screen upon switching the VR image to the AR image. 
       FIG. 8  is a flowchart illustrating an example image display method of an electronic device according to an example embodiment. 
     In operation  801 , the HMD device  200  on which the electronic device  100  is mounted may be driven. In various embodiments, the camera module  130  of the electronic device  100  may be activated as soon as the electronic device  100  is mounted on the HMD device  200 , at a point in time when a specified time elapses from a point in time when the HMD device  200  is driven, or at a point in time when the user wears the HMD device  200  on which the electronic device  100  is mounted. The activated camera module  130  may photograph an area in front of the HMD device  200 . The camera module  130  may transfer the photographed image to the processor  140  of the electronic device  100  in real time. 
     In operation  803 , the processor  140  may detect an object (e.g., an animal, a thing, a human body, or the like) existing (e.g., located) within a photographing range of the camera module  130  based on the image photographed by the camera module  130 . In the case where at least one object is detected, the processor  140  may calculate a distance from the HMD device  200  (or the user wearing the HMD device  200 ) to the detected object. 
     In operation  805 , the processor  140  may determine an area where the detected object is located, based on the calculated distance between the HMD device  200  and the detected object. An object that exists within the photographing range of the camera module  130  may be located in any one area of specified first, second, and third areas. The first area may include an area from the HMD device  200  to a point spaced apart therefrom by the specified first distance. The second area may include a second distance area between a boundary of the first area and a specified point of the photographing range. The third area may include the remaining area of the photographing range of the camera module  130  other than the first area and the second area. 
     If it is determined in operation  805  that the detected object is located within the first area, in operation  807 , the processor  140  may switch an image displayed in the display  120  into the photographed image by the camera module  130 . Alternatively, the processor  140  may switch an image displayed in the display  120  into an AR image including at least part of the photographed image by the camera module  130 . In this operation, the processor  140  may control other elements of the electronic device  10 , for example, such that specified notification sound or vibration of a specified pattern is output. 
     If it is determined in operation  805  that the detected object is located within the second area, in operation  809 , the processor  140  may add at least one content on the image displayed in the display  120 . For example, the content may include an icon, an image such as a shaded silhouette or a symbol, or a text such as characters, which are associated with the object  1  existing within the second area. In various embodiments, in the case where the object existing within the second area is a dynamic object, the processor  140  may control a location of the content on the image displayed in the display  120  to correspond to a location movement of the dynamic object. 
     Although not illustrated in  FIG. 8 , if it is determined in operation  805  that the object is located in the third area, the processor  140  may determine that the object is located at a point that is relatively distant from the HMD device  200 . Accordingly, the processor  140  may not perform an operation (e.g., the above-described image switching or content adding operation) of providing a separate notification with regard to the object located in the third area. 
       FIG. 9  is a flowchart illustrating an example image display method of an electronic device according to another example embodiment. Operations to be described below may be associated with an operation assumed in the operations described with reference to  FIG. 8 , for example. 
     In operation  901 , the HMD device  200  on which the electronic device  100  is mounted may be driven, and the camera module  130  of the electronic device  100  may be activated. The activated camera module  130  may perform first photographing on an area in front of the HMD device  200  and may transfer the photographed image to the processor  140  of the electronic device  100 . 
     In operation  903 , the processor  140  may detect an object (e.g., an animal, a thing, a human body, or the like) existing within a photographing range of the camera module  130  based on the image first photographed by the camera module  130 . If at least one or more objects are detected within the photographing range, the processor  140  may calculate the number of the detected objects. In various embodiments, the processor  140  may further calculate the size of the at least one object existing within the photographing range of the camera module  130 . 
     In operation  905 , the processor  140  may determine whether the calculated number of objects exceeds a specified threshold value. The specified threshold value may be set or changed by the user in consideration of an operating place of the HMD device  200 , for example. If the calculated number of objects exceeds the specified threshold value, in operation  907 , the processor  140  may switch an image displayed in the display  120  into at least one pop-up window. At least one text that is associated with a request to change a location of the HMD device  200  (or a location of the user wearing the HMD device  200 ) may be included in the pop-up window. 
     According to various embodiments, in operation  905 , the processor  140  may further determine whether the calculated object size exceeds a specified threshold size. If the calculated object size exceeds the specified threshold size, in addition, if the calculated object size is larger than the specified threshold size even though the calculated number of objects does not exceed the specified threshold value, in operation  907 , the processor  140  may switch the image displayed in the display  120  into a pop-up window. 
     As described above, a method of displaying an image for a head mounted electronic device may include displaying a virtual reality (VR) image in left-eye and right-eye lens areas, photographing an image of an area in front of the head mounted electronic device, detecting at least one object existing within a first area based on the photographed image, the first area being an area from the head mounted electronic device to a point spaced apart from the head mounted electronic device by a first distance, and switching the VR image to the photographed image or to an augmented reality (AR) image including at least part of the photographed image if at least one object exists within the first area. 
     According to various example embodiments, the method may further include detecting at least one object existing within a second area based on the photographed image, the second area being an area from a boundary of the first area to a point spaced apart from the boundary of the first area by a second distance, and adding at least one content associated with the at least one object existing within the second area to the VR image if at least one object exists within the second area. 
     According to various example embodiments, the adding of the at least one content may include allowing tracking a location variation of the object existing within the second area on the VR image. 
     According to various example embodiments, the method may further include determining, based on an image photographed after the head mounted electronic device is driven, a number of objects existing within a third area of a photographing range of the image other than the first area and the second area, and switching the VR image into at least one pop-up window if the determined number of objects exceeds a specified threshold number of objects. 
     According to various example embodiments, the pop-up window may include at least one text associated with a location change of the head mounted electronic device. 
     According to various example embodiments, t the photographing of the image may include starting photographing after a specified time elapses from a point in time when the head mounted electronic device is driven. 
     According to various example embodiments, the method may further include mounting, on the head mounted electronic device, an electronic device performing at least one of the photographing of the image, the detecting of the object, and the switching into the AR image. 
     According to various example embodiments, the photographing of the image may include starting photographing from a point in time when the electronic device is mounted on the head mounted electronic device. 
     According to various example embodiments, the switching to the AR image may include overlaying an image associated with at least part of the object existing within the first area on at least part of the VR image. 
     According to various example embodiments, the switching to the AR image may include separately displaying the VR image and the photographed image, each of which has a specified size, on a single screen. 
     According to various example embodiments, as an actually photographed image of an object adjacent to an HMD device is displayed on a screen displayed through the HMD device, it may be possible to perceive dangerous situations in a real space while operating the HMD device. 
     Besides, a variety of effects directly or indirectly understood through this disclosure may be provided. 
     While the present disclosure has been illustrated and described with reference to various example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.