Patent Publication Number: US-11657574-B2

Title: Systems and methods for providing an audio-guided virtual reality tour

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/425,945, filed May 30, 2019, which claims the benefits of priority to Chinese Application Nos. CN 201810538662.2, filed May 30, 2018 and CN 201810539141.9, filed May 30, 2018. The entire contents of the above-identified applications are expressly incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present application relates to virtual reality (VR) technologies. More specifically, the present application relates to systems and methods for providing an audio-guided VR tour in an in-door environment. 
     BACKGROUND 
     Conventional real estate sales rely on distribution of paper pamphlets and advertisement through newspaper and other paper-based media channels. These off-line advertising methods suffer from low efficiency and limited customer base. Promoting real estate sales on-line has become popular thanks to the proliferation of Internet and network-connected mobile devices. Real estate information augmentation services may collect for-sale information and distribute such information to subscribers through mailing list or publish the information on websites or mobile app portals. While the on-line approach improves the timeliness and reaches a larger audience, the contents delivered on-line remain largely the same as their off-line counterparts. For example, a typical on-line real estate advertisement includes a set of photos of the subject property and some textual descriptions. In order to gain more detailed knowledge about the property, such as specific parts not covered or insufficiently depicted by the photos, a visit to the property would normally be required. In addition, the textual descriptions are often provided in the form of a laundry list, lacking context to specific features of the underlying real estate property. 
     Embodiments of the present disclosure improve the user experience in exploring and virtually touring real estate properties by providing audio-guided VR tours. 
     SUMMARY 
     In one aspect, a system is provided for providing an audio-guided in-door VR tour. The system may include a communication interface configured to receive input from a user and to output media contents, a memory storing computer-readable instructions, and at least one processor coupled to the communication interface and the memory. The computer-readable instructions, when executed by the at least one processor, may cause the at least one processor to perform operations. The operations may include displaying, through the communication interface, a view of a three-dimensional (3D) VR environment. The operations may also include playing, through the communication interface, an audio guide associated with the view. The operations may further include detecting, during the playing of the audio guide, a target operation input by the user to alter the view. In response to the detection of the target operation, the operations may include adjusting, based on the detected target operation, the view with respect to a fixed point position within the 3D VR environment. 
     In another aspect, a method is provided for providing an audio-guided in-door virtual reality (VR) tour. The method may include displaying, through a communication interface, a view of a three-dimensional (3D) VR environment. The method may also include playing, through the communication interface, an audio guide associated with the view. The method may further include detecting, during the playing of the audio guide, a target operation input by a user to alter the view. In response to the detection of the target operation, the method may include adjusting, based on the detected target operation, the view with respect to a fixed point position within the 3D VR environment. 
     In a further aspect, a non-transitory computer-readable medium is provided. The non-transitory computer-readable medium may store instructions that, when executed by at least one processor, cause the at least one processor to perform a method for providing an audio-guided in-door virtual reality (VR) tour. The method may include displaying, through a communication interface, a view of a three-dimensional (3D) VR environment. The method may also include playing, through the communication interface, an audio guide associated with the view. The method may further include detecting, during the playing of the audio guide, a target operation input by a user to alter the view. In response to the detection of the target operation, the method may include adjusting, based on the detected target operation, the view with respect to a fixed point position within the 3D VR environment. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates an exemplary system for providing an in-door VR tour, according to embodiments of the disclosure. 
         FIG.  2    illustrates an exemplary three-dimensional (3D) VR environment, according to embodiments of the disclosure. 
         FIG.  3    illustrates a block diagram of an exemplary computer system configured to provide an in-door VR tour, according to embodiments of the disclosure. 
         FIGS.  4 A and  4 B  are flow charts of exemplary methods for providing an audio-guided in-door VR tour, according to embodiments of the disclosure. 
         FIG.  5    illustrates an exemplary user interface for displaying a view of a 3D VR environment, according to embodiments of the disclosure. 
         FIG.  6    illustrates an exemplary path of an in-door VR tour, according to embodiments of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       FIG.  1    illustrates an exemplary system  100  for providing an in-door VR tour, according to embodiments of the disclosure. System  100  may include a data capturing portion, a data processing portion, and a VR displaying portion. The data capturing portion may include a camera device  110  configured to capture images of an in-door environment  102 , which may include enclosed or partially-enclosed space, such as one or more rooms of a residential or commercial real estate property, passenger or cargo space of a vessel (e.g., car, truck, recreational vehicle, trailer, train, ship, plane, etc.), a hall/suite/room of a cultural, political, industrial, or business establishment, etc. In-door environment  102  may include fixtures (e.g., lights, fans, cabinets, closets, etc.), structures (furniture, decorations, etc.), or other features. In some embodiments, in-door environment  102  may include part of a real estate property that may be for sale or rent. For example, the example shown in  FIG.  1    depicts a living room of an apartment, house, or office building. Embodiments of the disclosure may create a 3D model of in-door environment  102  to facilitate the provision of a VR tour of the in-door environment. For example, multiple images of in-door environment  102  may be captured, aligned, and combined to recreate or reconstruct a 3D representation of the in-door environment  102 . In some embodiments, range, depth, or distance information may also be acquired to aid in creating the 3D model. 
     In some embodiments, camera device  110  may be configured to capture images of in-door environment  102 . The image data captured by camera device  110  may include static images or photos, motion images or videos, 3D images including range, depth, or distance information, or any combination thereof. For example, camera device  110  may include a specially designed VR camera or 3D camera configured to capture 3D images having range/depth/distance information. In this case, camera device  110  may include multiple lenses. One or more of the lenses may be configured to capture the color or intensity information, while one or more other lenses may be configured to capture the range/depth/distance information. The color/intensity information and range/depth/distance information may be stored locally in a memory of camera device  110 , transmitted to an accompanying mobile device  111  located in the proximity to the camera device, and/or streamed to a remote server, such as server  142  located in a cloud computing service  140 , which will be discussed in greater detail below. For example, when mobile device  111  is used, image data captured by camera device  110  may be transmitted to mobile device  111 , where the image data may be preprocessed, including, for example, aligning and/or combining point cloud data captured at different shooting angles or positions, adding one or more feature points such as those on windows or mirrors, and conditioning the image data for transmission, such as streaming, dividing into packets, and/or compressing the image data. 
     In some embodiments, camera device  110  may include a camera not specifically designed to acquire 3D model data, such as a general-purpose digital camera, a camera equipped on a mobile device (e.g., a smart phone camera, a tablet camera, a laptop camera, etc.), a webcam, an action/sports camera, a panorama or 360-degree camera, or the like. In this case, images captured by camera device  110  may be aligned and combined based on feature recognition, image registration, machine learning, or other suitable techniques to convert multiple patches of 2D images into a 3D model. 
     In some embodiments, camera device  110  may include, separate from the image capturing device, a range device such as a light-based sensor (e.g., infra-red, laser, etc.) to acquire range/depth/distance information, which may be associated with 2D images captured by camera device  110  to create a 3D model. 
     As shown in the example of  FIG.  1   , camera device  110  may be installed on a stand  112 . In some embodiments, stand  112  may include a tripod or similar supporting structures. Camera device  110  may be coupled to stand  112  through mounting, screwing, magnetically attaching, or any suitable mechanism to physically associate with stand  112 . 
     In some embodiments, camera device  110  may be rigidly associated with stand  112 . For example, the connection between camera device  110  and stand  112  may not allow significant movement of camera device  110  relative to stand  112 . In some embodiments, camera device  110  may be flexibly associated with stand  112 . For example, camera device  110  may be connected to stand  112  via a ball head, pan head, gimbal, CV-joint, track, slider, etc., to allow movement (e.g., tilt, pan, linear motion, or the like) of camera device  110  relative to stand  112 . In some embodiments, motion of camera device  110  may be manually or remotely controlled by an operator. In some embodiments, motion of camera device  110  may be automatically controlled by a motorized mechanism and may be based on a predetermined routine or feedback from the captured information. 
     In some embodiment, stand  112  may be equipped with a motion mechanism to move around. For example, stand  112  may include wheels or similar structures to allow movement within in-door environment  102 . Stand  112  may be motorized to propel itself. For example, stand  112  may be mounted on or integrated with a motorized base, cart, or robotic platform. In some embodiments, the motion of stand  112  may be controlled by an operator. In some embodiments, the motion of stand  112  may be automatically controlled based on a predetermined routine or feedback from the captured information. 
     In some embodiments, stand  112  may be omitted. For example, camera device  110  may be placed directly on any suitable surface or held by a user during an image capturing process. 
     The captured image data of in-door environment  102  may be processed by the data processing portion of system  100 . In some embodiments, the data processing portion may include a cloud computing service (also referred to as cloud service or simply cloud)  140  comprising one or more servers  142  (hereinafter collectively referred to as server  142 ). Image data captured by camera device  110  may be transmitted to cloud  140  via a communication channel  114 . In some embodiments, communication channel  114  may include a wired or physical connection, such as a data cable or card reader. In some embodiments, communication channel  114  may include a wireless connection, such as a wireless local area network (WLAN) connection, Bluetooth connection, telecommunication link (e.g., 3G, 4G, 5G, etc.), or the like. In some embodiments, when mobile device  111  is used to process the image data captured by camera device  110 , mobile device  111  may be part of the data processing portion. In this case, communication channel  114  may be between mobile device  111  and cloud  140  in addition to or instead of between camera device  110  and cloud  140 . 
     Server  142  may include data processing devices to process the image data received from camera device  110  and/or mobile device  111 . For example, the image data may include multiple images of in-door environment  102  captured at multiple locations and/or multiple shooting angles. The multiple images may include high-definition color photos, sometimes with multiple exposure levels, of features in the in-door environment  102 . The multiple images may also include or be associated with 3D range data (e.g., 3D point cloud data) and/or geographical information (e.g., GPS information) of in-door environment  102 . Based on the image data, server  142  may map the features contained in the images as well as image textures and details to a 3D model representing the in-door environment  102  using techniques such as automatic model creation, intelligent hole filling, automatic data extraction, and high-dynamic range (HDR) optimization. In this way, in-door environment  102  can be reconstructed in virtual reality to allow users to explore, examine, and experience the features of in-door environment  102  in high fidelity without being physically present therein. In some embodiments, part or all of the data processing may be performed by mobile device  111 . For example, mobile device  111  and server  142  may work in tandem to process the image data captured by camera device  110 . 
     Viewing or touring the reconstructed in-door environment  102  can be accomplished through various ways, such as using a terminal device. For example, as shown in  FIG.  1   , a user  122  may use a terminal device  120  to view or virtually tour the VR version of the in-door environment (referred to as VR environment  126 ) displayed on terminal device  120 . In some embodiments, terminal device  120  may communicate with cloud  140  to exchange information about displaying VR environment  126 . For example, data related to the VR environment  126 , such as the 3D model of in-door environment  102 , color information, texture information, spatial relationship among various features/objects, and one or more default view points, view angles, and/or filed of views may be transmitted from cloud  140  to terminal device  120  via a communication channel  124 . User  122  may manipulate the view point, view angle, and field of view in the VR environment  126  to explore various features, for example to virtually “move” along a route to change the view point, pan/tilt to change the view angle, and zoom in/out to change the field of view. These manipulations may be fed back to cloud  140  via communication channel  124  to update the content of the VR environment  126  displayed on terminal device  120 . Communication channel  124  may include any suitable wired or wireless connections between cloud  140  and terminal device  124 , such as a broadband connection (e.g., via WLAN, LAN, and/or short-range communication links such as Bluetooth), a telecommunication link (e.g., 3G, 4G, 5G, etc.), or the like. 
     VR environment  126  displayed on terminal device  120  may be enriched with various enrichment data. For example, audio description or guidance (referred to as audio guide) may be added to VR environment  126  to enrich the user experience. The audio guide may include a recorded voice guidance to introduce features of in-door environment  102 , background information, or other information to assist user  122  in understanding the features or characteristics of in-door environment  102 . In another example, video demonstration may be provided to showcase certain features displayed in VR environment  126 . In yet another example, one or more spatial operations altering the view of the VR environment  126  may be added to direct the user&#39;s attention to specific aspects of VR environment  126 . Exemplary spatial operations may include panning, tilting, zooming, sliding or moving in any suitable manner, etc. These multimedia contents enrich the VR environment  126  by engaging user  122  with additional layers of interactions, thereby improving the user experience. 
     Enrichment data such as audio description, video demonstration, and spatial operations altering the view of the VR environment  126  may be added by a user  132 . In some embodiments, user  132  may have a role falling within a predetermined authorization group, such as a realtor, an owner or manager of a real estate property, or the like. User  132  may operate a terminal device  130  to create enrichment data or upload pre-created enrichment data to cloud  140 . For example, terminal device  130  may display a 3D VR environment  136  (also referred to as VR environment  136  or environment  136  for simplicity) that may be similar to VR environment  126  but may include additional interface elements configured for creating or adding enrichment data. When user  132  is navigating through VR environment  136 , a user indicator, which may or may not be visible in VR environment  136 , may be used to determine the field of view depicted on terminal device  130 . For example, the user indicator may be represented by a point position within VR environment  136  simulating the position where user  132  is virtually located within VR environment  136  and/or a view direction toward which user  132  faces. The point position of the user indicator may coincide with the view point at which the view of the VR environment  126 / 136  displayed on terminal device  120 / 130  is perceived or observed. In some embodiments, the point position may correspond to the location at which the image data of in-door environment  102  is captured. For example, camera device  110  may be placed at a spatial location within in-door environment  102  to capture image data, which may be used to reconstruct the 3D model of in-door environment  102 . When the 3D model is displayed to user  120 / 130  in the form VR environment  126 / 136 , user  120 / 130  may be presented with a view of the VR environment as if the user is standing at the same spatial location of camera device  110  and to observe what camera device  110  can capture. In some embodiments, whether the user indicator is within VR environment  136  or not may indicate whether user  132  engages or experiences VR environment  136 . 
     Terminal device  130  may communicate with cloud  140  via communication channel  134 , which may be similar to communication channel  124 . Enrichment data created or uploaded by user  132  may be transmitted to cloud  140  via communication channel  134 . After receiving the enrichment data, cloud  140 , through server  142 , may update the 3D model of in-door environment  102  stored thereon by adding the enrichment data, and provide the updated VR environment  126  to user  122 . 
       FIG.  2    illustrates an exemplary 3D VR environment  200 , according to embodiments of the disclosure. As shown in  FIG.  2   , 3D VR environment  200  may simulate or represent a residential unit, such as an apartment or house floor. It is noted that 3D VR environment  200  is not limited to the example shown in  FIG.  2   . Rather, 3D VR environment  200  may include a VR representation of any in-door space or environment. Referring to  FIG.  2   , 3D VR environment  200  may include one or more functional spaces, such as  210 ,  220 ,  230 ,  240 ,  250 , and  260 . As used herein, a functional space refers to an enclosed or partially enclosed space that is associated with a particular function. In some cases, a functional space may correspond to a room. For example, functional space  210  may correspond to a first bedroom, and functional space  230  may correspond to a second bedroom. In some cases, a functional space may correspond to an enclosed or partially enclosed space within or adjacent to a room. For example, functional space  240  may correspond to a closet. In some cases, a function space may correspond to an area that is generally used for a specific purpose. For example, functional space  220  may correspond to a kitchen area, functional space  250  may correspond to a dining area, and functional space  260  may correspond to a living room. Although functional spaces  220 ,  250 , and  260  may share the same room (e.g., an enclosed area), they may be considered as different functional spaces due to their different functions. 
       FIG.  3    illustrates a block diagram of an exemplary computer system  300  configured to implement various functions disclosed herein. For example, computer system  300  may be configured as server  142  to create or reconstruct VR environment  126 . In another example, computer system  300  may be configured as terminal device  120  or  130  to display or enrich VR environment  126 / 136 . As shown in  FIG.  3   , computer system  300  may include a processor  310 , a communication interface  320 , a memory/storage  330 , and a data bus  340 . Memory/storage  330  may be configured to store computer-readable instructions that, when executed by processor  310 , can cause processor  310  to perform various operations disclosed herein. Memory  330  may be any non-transitory type of mass storage, such as volatile or non-volatile, magnetic, semiconductor-based, tape-based, optical, removable, non-removable, or other type of storage device or tangible computer-readable medium including, but not limited to, a ROM, a flash memory, a dynamic RAM, and a static RAM. 
     Processor  310  may be configured to perform the operations in accordance with the instructions stored in memory  330 . Processor  310  may include any appropriate type of general-purpose or special-purpose microprocessor, digital signal processor, microcontroller, or the like. Processor  310  may be configured as a separate processor module dedicated to performing one or more specific operations disclosed herein. Alternatively, processor  310  may be configured as a shared processor module capable of performing other operations unrelated to the one or more specific operations disclosed herein. 
     Communication interface  320  may be configured to communicate information between computer system  300  and other devices or systems. For example, communication interface  320  may include an integrated services digital network (ISDN) card, a cable modem, a satellite modem, or a modem to provide a data communication connection. As another example, communication interface  320  may include a local area network (LAN) card to provide a data communication connection to a compatible LAN. As a further example, communication interface  320  may include a high-speed network adapter such as a fiber optic network adaptor, 10G Ethernet adaptor, or the like. Wireless links can also be implemented by communication interface  320 . In such an implementation, communication interface  320  can send and receive electrical, electromagnetic or optical signals that carry digital data streams representing various types of information via a network. The network can typically include a cellular communication network, a Wireless Local Area Network (WLAN), a Wide Area Network (WAN), or the like. 
     Communication interface  320  may also include various I/O devices such as a display  322 , a microphone  324 , a speaker or speaker module  326 , a keyboard, a mouse, a touchpad, a touch screen, a camera, a biosensor, etc. User  122 / 132  may input data to and/or receive information from terminal device  120 / 130  through communication interface  320 . 
     Display  322  may be integrated as part of computer system  300  or may be provided as a separate device communicatively coupled to computer system  300 . Display  322  may include a display device such as a Liquid Crystal Display (LCD), a Light Emitting Diode Display (LED), a plasma display, or any other type of display, and provide a Graphical User Interface (GUI) presented on the display for user input and data depiction. In some embodiments, display device  322  may include a VR goggle, a pair of VR glasses, or other similar devices that provide immersive VR experience. For example, VR environment  126 / 136  may be displayed on display  322 . In some embodiments, display  322  may be integrated as part of communication interface  320 . 
     Microphone  324  may include any suitable audio input device configured to receive audio signals and convert the audio signals to electrical signals. For example, user  132  may record an audio guide through microphone  324  as part of the enrichment data. 
     Speaker (or speaker module)  326  may include any suitable audio output device. In some embodiments, speaker  326  may include an audio transducer to convert electrical signals to audio signals. In some embodiments, speaker  326  may take the form of a digital to analog converter to convert digital audio signals to analog signals, which can be further converted to audio signals by a separate audio transducer. 
     Data bus  340  may include any suitable communication medium configured to facilitate data exchange among components of computer system  300 . 
       FIG.  4 A  illustrates a flowchart of an exemplary method  400  for providing an audio-guided VR tour of an in-door environment (e.g., in-door environment  102 ), according to embodiments of the disclosure. In some embodiments, method  400  may be implemented by server  142 . However, method  400  is not limited to that exemplary embodiment and may be implemented by terminal device  120 / 130  or jointly by server  142  and terminal device  120 / 130 . As discussed above, server  142  and/or terminal device  120 / 130  may be implemented by computer system  300 . Method  400  may include steps  402 - 416  as described below. It is to be appreciated that some of the steps may be optional to perform the disclosure provided herein. Further, some of the steps may be performed simultaneously, or in a different order than shown in.  FIG.  5    illustrates an exemplary user interface for displaying a view of a 3D VR environment, according to embodiments of the disclosure. Method  400  will be de discussed together with  FIGS.  3  and  5   . 
     In step  402 , processor  310  may, through communication interface  320  (e.g., display  322 ), display an audio guide control on a launching page of an audio-guided in-door VR tour.  FIG.  5    illustrate an exemplary audio guide control  510  on an exemplary launching page  502 , according to embodiments of the disclosure. As shown in  FIG.  5   , audio guide control  510  may include components such as a user profile icon  512  (e.g., an image, photo, or avatar of the audio guide narrator), an audio guide description  514 , and/or a play button  516 . In some embodiments, audio guide control  510  may include few components then the example shown in  FIG.  5   . For example, an alternative or additional play button  520  (may be used as an audio guide control by itself) may be provided on launching page  502 . Launching page  502  may be an interface where a user can launch or start an audio-guided VR tour. For example, launching page  502  may be the first page shown to the user after the user select an in-door environment or a functional space of an in-door environment. Launching page  502  may include a photo, image, and/or VR representation associated with the audio-guided in-door VR tour and/or the underlying in-door environment or functional space. Displaying audio guide control  510 / 520  on launching page  502  allows the user to launch a VR tour quickly and conveniently, improving the user experience. 
     Processor  310  may generate audio guide control  510  by acquiring an audio file and corresponding VR images and storing the combination in memory/storage  330 . Processor  310  may also acquire information of user profile icon  512  and the description of the audio guide  514 . Processor  310  may then load user profile icon  512  and description  514 , along with play button  516 , into audio guide control  510  for display on launching page  502 . Processor  310  may establish the mapping relationship between play button  516  and the audio file and corresponding VR images stored in memory/storage  330  to allow automatically playing of the audio guide and displaying the corresponding view of the VR environment. 
     In step  404 , processor  310  may determine whether to receive, through communication interface  320  (e.g., a touchscreen, keyboard, mouse, etc.), an instruction or trigger from the user triggering audio guide control  510 / 520 . For example, processor  310  may determine whether the user click, touch, or hold audio guide control  510 / 520  to initiate the audio guide. If processor  310  does not receive such an instruction or trigger, method  400  returns to step  402  following the NO branch, in which processor  310  continue waiting for the instruction or trigger (e.g., in a stand-by mode). On the other hand, after processor  310  receives such an instruction or trigger from the user, method  400  proceeds to steps  406  and  408  following the YES branch in response to the reception of the instruction or trigger. It is noted that step  406  and  408  may be performed sequentially in any order (e.g., step  406  followed by step  408  or vice versa) or, at substantially the same time. 
     In step  406 , processor  310  may display, through communication interface  320  (e.g., display  322 ), a view of a 3D VR environment, such as a view of VR environment  126 / 136 . As used herein, a view of a 3D VR environment may include at least a partial display of the 3D VR environment observed at a point position and having a field of view (FOV). Altering the view angle, direction, or performing zooming-in/out may change the FOV, thereby altering the view. In some embodiments, multiple views may be provided to the user when the user manipulate the FOV (e.g., by sliding, zooming-in, or zooming-out). 
     In step  408 , processor  310  may play, through communication interface  320 , an audio guide associated with the view displayed to the user. As discussed above, steps  406  and  408  may be performed simultaneously upon receiving the user instruction or trigger by, for example, clicking play button  516  or  520 . In some embodiments, multiple views may be associated with the audio guide. As the audio guide is playing back, a sequence of views may be displayed to the user, based on a pre-recorded sequence of spatial operations to alter the view. For example, user  132  may pre-record the audio guide by inputting voice signals along with a series of spatial operations to manipulate the FOV of the view to, for example, showcase certain features. The sequence of spatial operations may also be recorded and associated with the audio guide. When the audio guide is played back, the recorded spatial sequence may also be played back, for example in synchronization with the audio guide, to provide a dynamic VR experience and to better focus on certain features of the underlying in-door environment. 
     During the playing of the audio guide, the user may be allowed to alter the default view associated with the audio guide that is being displayed. For example, processor  310  may detect a target operation input by the user to alter the view in step  410 . In some embodiments, the target operation may include altering the FOV for observing the VR environment. For example, the user may slide the view on a touch screen in any direction (e.g., up, down, left, right, angular, or a combination thereof) to change the view direction or view angle. In another example, the user may zoom in the view (e.g., by clicking a zoom-in button or by using gesture operations such as a two-finger pinching operation) to shrink the FOV. In yet another example, the user may zoom out the view (e.g., by clicking a zoom-out button or by using gesture operations such as a two-finger pinching operation) to enlarge the FOV. Depending on applications, one or more of such FOV altering operations may be set as target operations. In response to the detection of the target operation in step  410 , processor  310  may, in step  412  following the YES branch of step  410 , adjust the view based on the detected target operation. 
     In some embodiments, the adjustment of the view may be with respect to a fixed point position within the VR environment. For example, when the target operation is a sliding operation, processor  310  may adjust the view according to the sliding direction, acceleration, speed, or other properties, but without changing the viewing point position. In other words, the view adjustment may be allowed under the condition that the user indicator (e.g., the view point) is fixed to a point position within the VR environment. In some embodiments, the fixed point position may correspond to a point position at which the view is displayed when the target operation is detected. For example, as the audio guide is playing, one or more preset views associated with the audio guide may be displayed to the user, which may be at different point positions. When the target operation is detected, processor  310  may determine the current point position at which the view is being displayed as the fixed point position and alter the view at the fixed point position without moving to another point position. For instance, when the target operation is a zoom operations (zooming in or zooming out), processor  310  may adjust the FOV to reflect the zoomed view observed at the fixed point position. In other words, during the playing of the audio guide, the user is permitted to manipulate the view to observe the VR environment with limited flexibility, namely at a fixed point position. This fixed point position may be dynamically determined, as discussed above, as the point position at the time when the target operation is detected. The fixed point position may also be one of a predetermined set, for example, corresponding to a point position at which the view is captured by camera device  110 . 
     In some embodiments, processor  310  may restrict certain operations input by the user. For example, the fixed point position may be within a first functional space, such as a fixed point position  610  within functional space  210  shown in  FIG.  6   . An operation by the user to jump to another functional space while the audio guide is playing may be prohibited. Steps  414  and  416  show an exemplary process to restrict such an operation. Referring back to  FIG.  4 A , when processor  310  does not detect a target operation (the NO branch of step  410 ), method  400  may proceed to step  414 , in which processor  310  may detect whether an operation to change the view from a first functional space (e.g., functional space  210  shown in  FIG.  6   ) to a second functional space (e.g., functional space  250  shown in  FIG.  6   ), which is different from the first functional space. If no such operation is detected, method  400  may loop back to step  410 . On the other hand, if such an operation is detected by processor  310 , in response to the detection, processor  310  may, in step  416 , deny the operation of jumping among functional spaces and may send, through communication interface  320 , an alert indicating the operation is not permitted (e.g., an audible alert output by speaker  326 , a visual alert output by display  322 , etc.). 
     Allow limited flexibility to change the view displayed on a terminal device (e.g., terminal device  120 ) may encourage user  122  to explore VR environment  126  while listening to the audio guide, and at the same time maintain a degree of order to prevent user  122  from losing focus. Processor  310  programmed based on exemplary method  400  improve the user experience as well as the efficiency of the VR tour. 
       FIG.  4 B  illustrate another exemplary method  400 ′ for providing a VR tour, according to embodiments of the disclosure. Method  400 ′ is similar to method  400  in that steps  402  to  412  are the same, while steps  414  and  416  are replaced by steps  418  and  420 , respectively. Accordingly, description of steps  402  to  412  of method  400 ′ are omitted. Following the NO branch of step  410 , in step  418 , if processor  310  does not detect any target operation, and the waiting or standby time exceeds a predetermined time period, method  400 ′ proceeds to step  420 . If the predetermined time period has not been reached, method  400 ′ may loop back to step  410 . 
     In step  420 , processor  310  may proceed the user indicator from the first point position associated with the audio guide to a second point position. The second point position may be the next point position along a predetermined path of the audio-guided VR tour. In this way, processor  310  may sequentially proceed through a series of point positions, with the audio guide being played along the path, to complete the VR tour. 
       FIG.  6    shows an exemplary procession of point positions along a path of an in-door VR tour, according to embodiments of the disclosure. A user, such as user  120 , may start an audio-guided VR tour by, for example, clicking play button  516  or  520  displayed on the launching page  502 . The VR tour may start by displaying a view of a VR environment, such as a VR view of functional space  210  at point position  610 , along with an audio guide describing the features of functional space  210 . During the playing of the audio guide, user  120  may change the view by inputting a target operation, such as a sliding or zooming operation. The view displayed may be adjusted accordingly. The adjusted view may be from the view point fixed at point position  610 . During the playing of the audio guide, the point position may also change according to a predetermined sequence. For example, at a first time point, the point position may be at  610 . At a second time point, the point position may proceed to  612 . If the user inputs a target operation at the first time point, the view may be adjusted with respect to the fixed point position at  610 . If the user inputs a target operation at the second time point, the view may be adjusted with respect to the fixed point position at  612 . If the user inputs an operation attempting to change the functional space (e.g., from  210  to  250 ), processor  310  may deny that operation and send an alert indicating the operation is not permitted. 
     After a predetermined time period has passed, if processor  310  does not receive any target operation, processor  310  may proceed to the next point position along a pass and display the default view at the next point position. For example, processor  310  may proceed from point position  612  to point position  650  along pass  615 . During the procession, processor  310  may display 3D VR images along pass  615  to simulate the process of moving along the path. In some embodiments, there may be multiple point positions along pass  615 . Processor  310  may proceed to each point position along pass  615  and display the corresponding VR images at each point position. The procession may be at a constant speed from point position  612  to each intermediate point positions and finally to point position  650 . The procession may from one functional space to another functional space (e.g., from point position  612  in functional space  210  to point position  650  in functional space  250 ), or within the same functional space (e.g., from point position  610  to point position  612 , both in functional space  210 ). Similarly, after a predetermined time period, processor  310  may again proceed from point position  650  to point position  630  along a path  635  and to display the 3D VR images along the pass at a predetermined speed. 
     Another aspect of the disclosure is directed to a non-transitory computer-readable medium storing instructions which, when executed, cause one or more processors to perform the methods, as discussed above. The computer-readable medium may include volatile or non-volatile, magnetic, semiconductor, tape, optical, removable, non-removable, or other types of computer-readable medium or computer-readable storage devices. For example, the computer-readable medium may be the storage device or the memory module having the computer instructions stored thereon, as disclosed. In some embodiments, the computer-readable medium may be a disc or a flash drive having the computer instructions stored thereon. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed system and related methods. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed system and related methods. 
     It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.