Point cloud data transmission device, point cloud data transmission method, point cloud data reception device, and point cloud data reception method

1. A method of transmitting point cloud data by an apparatus, the method comprising:

acquiring point cloud data that is comprised of points;

encoding geometry information included in the point cloud data;

encoding attribute information included in the point cloud data; and

transmitting the encoded geometry information, the encoded attribute information and signaling information,

wherein the encoding the attribute information comprises:

selecting attribute information of at least one of occupied nodes in an octree for predicted attribute information of a node to be attribute-encoded, wherein the octree having an octal tree structure is generated by recursively subdividing a bounding box for the point cloud data, wherein the octree is formed of levels, wherein each of the levels includes a plurality of nodes, wherein each of the plurality of nodes is an occupied node that includes one or more points or a unoccupied node that does not include any point, and wherein, when a parent node of the node to be attribute-encoded includes two or more occupied child nodes, one of the two or more occupied child nodes is selected for the predicted attribute information,

acquiring residual attribute information based on attribute information of the node to be attribute-encoded and the predicted attribute information, and

encoding the residual attribute information,

wherein the signaling information includes information for indicating an attribute coding method and information related to the prediction of the attribute information.

2. An apparatus for transmitting point cloud data, the apparatus comprising:

an acquirer configured to acquire point cloud data that is comprised of points;

a geometry encoder configured to encode geometry information included in the point cloud data;

an attribute encoder configured to encode attribute information included in the point cloud data; and

a transmitter configured to transmit the encoded geometry information, the encoded attribute information and signaling information,

wherein the attribute encoder selects attribute information of at least one of occupied nodes in an octree for predicted attribute information of a node to be attribute-encoded, acquires residual attribute information based on attribute information of the node to be attribute-encoded and the predicted attribute information, and encodes the residual attribute information,

wherein the octree having an octal tree structure is generated by recursively subdividing a bounding box for the point cloud data, wherein the octree is formed of levels, wherein each of the levels includes a plurality of nodes, wherein each of the plurality of nodes is an occupied node that includes one or more points or a unoccupied node that does not include any point, wherein, when a parent node of the node to be attribute-encoded includes two or more occupied child nodes, one of the two or more occupied child nodes is selected for the predicted attribute information, and

wherein the signaling information includes information for indicating an attribute coding method and information related to the prediction of the attribute information.

3. A method of receiving point cloud data by an apparatus, the method comprising:

receiving encoded geometry information, encoded attribute information and signaling information;

decoding the encoded geometry information based on the signaling information;

decoding the encoded attribute information based on an octree and the signaling information; and

rendering point cloud data that is comprised of points by processing the decoded geometry information and the decoded attribute information,

wherein the decoding the attribute information comprises:

selecting attribute information of at least one of occupied nodes in the octree for predicted attribute information of a node to be attribute-decoded based on the signaling information, wherein the octree having an octal tree structure is generated by recursively subdividing a bounding box for the point cloud data, wherein the octree is formed of levels, wherein each of the levels includes a plurality of nodes, wherein each of the plurality of nodes is an occupied node that includes one or more points or a unoccupied node that does not include any point, and wherein, when a parent node of the node to be attribute-encoded includes two or more occupied child nodes, one of the two or more occupied child nodes is selected for the predicted attribute information, and

restoring attribute information of the node to be attribute-decoded based on the predicted attribute information and residual attribute information in the encoded attribute information,

wherein the signaling information includes information for indicating an attribute coding method and information related to the prediction of the attribute information.

4. An apparatus for receiving point cloud data, the apparatus comprising:

a receiver configured to receive encoded geometry information, encoded attribute information and signaling information;

a geometry decoder configured to decode the encoded geometry information based on the signaling information;

an attribute decoder configured to decode the encoded attribute information based on an octree and the signaling information; and

a renderer configured to render point cloud data that is comprised of points by processing the decoded geometry information and the decoded attribute information,

wherein the attribute decoder selects attribute information of at least one of occupied nodes in the octree as predicted attribute information of a node to be attribute-decoded based on the signaling information, and restores attribute information of the node to be attribute-decoded based on the predicted attribute information and residual attribute information in the encoded attribute information,

wherein the octree having an octal tree structure is generated by recursively subdividing a bounding box for the point cloud data, wherein the octree is formed of levels, wherein each of the levels includes a plurality of nodes, wherein each of the plurality of nodes is an occupied node that includes one or more points or a unoccupied node that does not include any point, wherein, when a parent node of the node to be attribute-encoded includes two or more occupied child nodes, one of the two or more occupied child nodes is selected for the predicted attribute information, and

wherein the signaling information includes information for indicating an attribute coding method and information related to the prediction of the attribute information.