Three-dimensional data encoding method, three-dimensional data decoding method, three-dimensional data encoding device, and three-dimensional data decoding device

1. A three-dimensional data encoding method comprising:

generating a layered structure including one or more layers by hierarchically arranging three-dimensional points each having an attribute information item;

encoding the attribute information item of each of the three-dimensional points using the layered structure; and

generating a first bitstream including the attribute information item encoded and an identification information item indicating whether the three-dimensional points are re-ordered in Morton order.

2. The three-dimensional data encoding method according to claim 1 ,

wherein when the identification information item indicates that the three-dimensional points are not re-ordered in the Morton order, in the generating of the layered structure, the three-dimensional points are not re-ordered in the Morton order.

3. The three-dimensional data encoding method according to claim 1 ,

wherein when the identification information item indicates that the three-dimensional points are re-ordered in the Morton order, in the generating of the layered structure, the three-dimensional points are re-ordered in the Morton order.

4. The three-dimensional data encoding method according to claim 1 ,

wherein the layered structure includes one layer.

5. The three-dimensional data encoding method according to claim 1 ,

wherein the layered structure includes two or more layers, and

the three-dimensional points are classified into the two or more layers in such a way that a distance between three-dimensional points belonging to a higher layer is longer than a distance between three-dimensional points belonging to a lower layer.

6. The three-dimensional data encoding method according to claim 1 , further comprising:

generating a second bitstream when the layered structure includes two or more layers, the second bitstream including the attribute information item encoded and a layer information item used in generating the layered structure including the layers.

7. The three-dimensional data encoding method according to claim 6 ,

wherein the second bitstream does not include the identification information item.

8. A three-dimensional data decoding method comprising:

obtaining a bitstream including an attribute information item encoded based on three-dimensional points arranged hierarchically to form a layered structure including one or more layers; and

decoding the attribute information item encoded, based on whether the bitstream includes an identification information item indicating whether the three-dimensional points are re-ordered in Morton order.

9. The three-dimensional data decoding method according to claim 8 ,

wherein in the decoding, in a case where the bitstream is a first bitstream including the identification information item,

when the identification information item indicates that the three-dimensional points are not re-ordered in the Morton order, the layered structure is generated by hierarchically arranging the three-dimensional points without re-ordering the three-dimensional points in the Morton order, and the attribute information item encoded is decoded using the layered structure.

10. The three-dimensional data decoding method according to claim 8 ,

wherein in the decoding, in a case where the bitstream is a first bitstream including the identification information item,

when the identification information item indicates that the three-dimensional points are re-ordered in the Morton order, the three-dimensional points are re-ordered in the Morton order, based on position information items of the three-dimensional points, the layered structure is generated by hierarchically arranging the three-dimensional points re-ordered, and the attribute information item encoded is decoded using the layered structure generated.

11. The three-dimensional data decoding method according to claim 9 ,

wherein the first bitstream indicates that a layered structure including one layer is generated.

12. The three-dimensional data decoding method according to claim 8 ,

wherein the layered structure includes two or more layers, and

the three-dimensional points are classified into the two or more layers in such a way that a distance between three-dimensional points belonging to a higher layer is longer than a distance between three-dimensional points belonging to a lower layer.

13. The three-dimensional data decoding method according to claim 8 ,

wherein in the decoding, in a case where the layered structure includes two or more layers, and the bitstream is a second bitstream including a layer information item used in generating a layered structure including layers, the layered structure including the layers is generated by hierarchically arranging the three-dimensional points using the layer information item, and the attribute information item encoded is decoded using the layered structure generated.

14. The three-dimensional data decoding method according to claim 13 ,

wherein the second bitstream does not include the identification information item.

15. A three-dimensional data encoding device comprising:

a processor; and

memory,

wherein using the memory, the processor:

generates a layered structure including one or more layers by hierarchically arranging three-dimensional points each having an attribute information item;

encodes the attribute information item of each of the three-dimensional points using the layered structure; and

generates a first bitstream including the attribute information item encoded and an identification information item indicating whether the three-dimensional points are re-ordered in Morton order.

16. A three-dimensional data decoding device comprising:

a processor; and

memory,

wherein using the memory, the processor:

obtains a bitstream including an attribute information item encoded based on three-dimensional points arranged hierarchically to form a layered structure including one or more layers; and

decodes the attribute information item encoded, based on whether the bitstream includes an identification information item indicating whether the three-dimensional points are re-ordered in Morton order.