XR device and method for controlling the same

1. An extended reality (XR) device comprising:

a communication module configured to communicate with a Head-Mounted Display (HMD) that is worn by a user to provide the user with Virtual Reality (VR) content;

a camera configured to receive an image of a first space including the user; and

a processor configured to transmit VR content to the HMD through the communication module,

wherein the processor is further configured to:

recognize a position of the user and positions of real-world objects within the image of the first space, create a first tree structure composed of nodes corresponding to the real-world objects,

store the first tree structure in a memory of the XR device, wherein the nodes include information about positions and sizes of the real-world objects,

determine whether the user moves closer to at least one of the real-world objects by a predetermined distance or less using the first tree structure,

when the user moves closer to the at least one of the real-world objects by the predetermined distance or less, warn the user of a possibility of collision with the at least one of the real-world objects,

recognize bounding-boxes of the real-world objects within the image,

determine whether the user has moved closer to at least one of the bounding-boxes of the real-world objects by a predetermined distance or less,

recognize a bounding-box of at least one body part of the user within the image, and

determine whether the bounding-box of the at least one body part moves closer to at least one of the bounding-boxes of the real-world objects by a predetermined distance or less.

2. The XR device according to claim 1 , wherein the processor is further configured to determine whether the user has moved closer to at least one object corresponding to at least one node from among the nodes by a predetermined distance or less.

3. The XR device according to claim 1 , wherein the real-world objects include at least one object that does not move at all within the image, and at least one object that is not changed in size within the image.

4. The XR device according to claim 1 , wherein the processor is further configured to:

when a new object, that has moved within the image of the first space or has been changed in size within the image of the first space, is recognized, add a new node corresponding to the new object to the first tree structure, and

store the first tree structure added with the new node in the memory,

wherein the new node includes information about a position and size of the new object.

5. The XR device according to claim 1 , wherein the processor is further configured to:

after the user has moved from one position to another position, when a specific object, which has been covered by the user prior to the movement of the user, is recognized, add a specific node corresponding to the specific object to the first tree structure, and

store the first tree structure added with the specific node in the memory,

wherein the specific node includes information about a position and size of the specific object.

6. The XR device according to claim 1 , wherein:

the memory stores the first tree structure and a second tree structure that is composed of respective nodes corresponding to objects included in a second space different from the first space,

the processor is further configured to:

when the user moves between the first space and the second space, create a third tree structure that is composed of nodes related to a movement direction of the user from among nodes included in the first and second tree structures,

store the third tree structure in the memory, and

determine whether the moving user moves closer to at least one of objects included in the third tree structure by a predetermined distance or less.

7. The XR device according to claim 1 , wherein the processor is further configured to transmit collision alert information to the HMD through the communication module such that the collision alert information including information about a direction of the at least one of the real-world objects located adjacent to the user and an estimated collision distance of the at least one of the real-world objects located adjacent to the user is displayed on an output screen image of the VR content of the HMD.

8. A method for controlling an extended reality (XR) device, the method comprising:

transmitting Virtual Reality (VR) content to a Head-Mounted Display (HMD) worn by a user;

receiving an image of a first space including the user through a camera;

recognizing a position of the user and positions of real-world objects within the image of the first space;

creating a first tree structure composed of nodes corresponding to the real-world objects, storing the first tree structure in a memory of the XR device, wherein the nodes include information about positions and sizes of the real-world objects;

determining that the user moves closer to at least one of the real-world objects by a predetermined distance or less using the stored first tree structure;

warning the user of a possibility of collision with the at least one of the real-world objects located adjacent to the user according to a result of the determining;

recognizing bounding-boxes of the real-world objects within the image;

determining whether the user has moved closer to at least one of the bounding-boxes of the real-world objects by a predetermined distance or less;

recognizing a bounding-box of at least one body part of the user within the image; and

determining whether the bounding-box of the at least one body part moves closer to at least one of the bounding-boxes of the real-world objects by a predetermined distance or less.

9. The method according to claim 8 , wherein the determining that the user moves closer to at least one of the real-world objects includes:

determining whether the user has moved closer to at least one object corresponding to at least one node from among the nodes by a predetermined distance or less.

10. The method according to claim 8 , wherein the real-world objects include at least one object that does not move at all within the image, and at least one object that is not changed in size within the image.

11. The method according to claim 8 , further comprising:

when a new object, that has moved within the image of the first space or has been changed in size within the image of the first space, is recognized, adding a new node corresponding to the new object to the first tree structure, and storing the first tree structure added with the new node in the memory,

wherein the new node includes information about a position and size of the new object.

12. The method according to claim 8 , wherein the determining that the user moves closer to at least one of the real-world objects includes:

after the user has moved from one position to another position,

when a specific object, which has been covered by the user prior to the movement of the user, is recognized, adding a specific node corresponding to the specific object to the first tree structure, and storing the first tree structure added in the specific node in the memory,

wherein the specific node includes information about a position and size of the specific object.

13. The method according to claim 8 , wherein:

the memory stores the first tree structure and a second tree structure that is composed of respective nodes corresponding to objects included in a second space different from the first space,

wherein the determining that the user moves closer to at least one of the real-world objects includes:

when the user moves between the first space and the second space, creating a third tree structure that is composed of nodes related to a movement direction of the user from among nodes included in the first and second tree structures, and storing the third tree structure in the memory, and

determining whether the moving user moves closer to at least one of objects included in the third tree structure by a predetermined distance or less.

14. The method according to claim 8 , wherein the warning the user of the possibility of collision with the at least one of the real-world objects located adjacent to the user includes:

transmitting collision alert information to the HMD such that the collision alert information including information about a direction of the at least one of the real-world objects located adjacent to the user and an estimated collision distance of the at least one of the real-world objects located adjacent to the user is displayed on an output screen image of the VR content of the HMD.