Decoding method, encoding method, decoding device, and encoding device
View Patent ↗A decoding method includes: calculating a first position on a polar coordinate system, using a first residual generated by predicting a position of a first three-dimensional point on the polar coordinate system; calculating a second position by transforming the polar coordinate system of the first position into a Cartesian coordinate system; decoding the position of the first three-dimensional point on the Cartesian coordinate system by adjusting the second position using a second residual of the Cartesian coordinate system; and decoding attribute information of the first three-dimensional point, using the first position before the transforming.
1 . A decoding method for decoding three-dimensional point cloud data, the decoding method comprising:
calculating a first position on a polar coordinate system by adding up a first predicted value and a first residual value included in a bitstream, the first residual value being a difference between a position of a first three-dimensional point on the polar coordinate system and the first predicted value;
calculating a second position by transforming the polar coordinate system of the first position into a Cartesian coordinate system;
decoding the position of the first three-dimensional point on the Cartesian coordinate system by adding up the second position and a second residual value included in the bitstream, the second residual being a difference between the position of the first three-dimensional point on the Cartesian coordinate system and the second position; and
decoding attribute information of the first three-dimensional point, using the first position on the polar coordinate system before the transforming the polar coordinate system of the first position into the Cartesian coordinate system.
2 . The decoding method according to claim 1 , further comprising:
decoding a position of a second three-dimensional point on the Cartesian coordinate system by calculating a third position by adding up a second predicted value and a third residual value included in the bitstream, the third residual value being a difference between the position of the second three-dimensional point on the Cartesian coordinate system and the second predicted value;
calculating a fourth position by transforming the Cartesian coordinate system of the third position into the polar coordinate system; and
decoding attribute information of the second three-dimensional point, using the fourth position.
3 . The decoding method according to claim 1 , further comprising:
normalizing the first position before the transforming, wherein
in the decoding of the attribute information of the first three-dimensional point, the normalized first position is used.
4 . The decoding method according to claim 1 , wherein
in the decoding of the position of the first three-dimensional point on the Cartesian coordinate system, the second residual included in the bitstream is inverse-quantized, and the position of the first three-dimensional point on the Cartesian coordinate system is decoded by adding up the second position and the inverse-quantized second residual.
5 . An encoding method for encoding three-dimensional point cloud data, the encoding method comprising:
calculating a first position by transforming a coordinate system of a position of a first three-dimensional point on a Cartesian coordinate system into a polar coordinate system;
generating a first residual that is a difference between the first position on the polar coordinate system and a first predicted value;
calculating a second position by transforming the polar coordinate system of the first position into the Cartesian coordinate system;
generating a second residual that is a difference between the second position and the position of the first three-dimensional point on the Cartesian coordinate system;
encoding attribute information of the first three-dimensional point, using the first position; and
generating a bitstream including the first residual, the second residual, and the encoded attribute information.
6 . The encoding method according to claim 5 , further comprising:
generating a third residual that is a difference between a third position of a second three-dimensional point on the Cartesian coordinate system and a second predicted value; and
encoding attribute information of the second three-dimensional point, using a fourth position of the second three-dimensional point on the polar coordinate system.
7 . The encoding method according to claim 5 , further comprising:
normalizing the first position; and
in the encoding of the attribute information of the first three-dimensional point, the normalized first position is used.
8 . The encoding method according to claim 5 , further comprising:
quantizing the second residual, wherein
the bitstream includes the quantized second residual.
9 . A decoding device for decoding three-dimensional point cloud data, the decoding device comprising:
a processor; and
memory, wherein
using the memory, the processor:
calculates a first position on a polar coordinate system by adding up a first predicted value and a first residual value included in a bitstream, the first residual value being a difference between a position of a first three-dimensional point on the polar coordinate system and the first predicted value;
calculates a second position by transforming the polar coordinate system of the first position into a Cartesian coordinate system;
decodes the position of the first three-dimensional point on the Cartesian coordinate system by adding up the second position and a second residual value included in the bitstream, the second residual being a difference between the position of the first three-dimensional point on the Cartesian coordinate system and the second position; and
decodes attribute information of the first three-dimensional point, using the first position on the polar coordinate system before the transforming the polar coordinate system of the first position into the Cartesian coordinate system.
10 . An encoding device for encoding three-dimensional point cloud data, the encoding method comprising:
a processor; and
memory, wherein
using the memory, the processor:
calculates a first position by transforming a coordinate system of a position of a first three-dimensional point on a Cartesian coordinate system into a polar coordinate system;
generates a first residual that is a difference between the first position on the polar coordinate system and a first predicted value;
calculates a second position by transforming the polar coordinate system of the first position into the Cartesian coordinate system;
generates a second residual that is a difference between the second position and the position of the first three-dimensional point on the Cartesian coordinate system;
encodes attribute information of the first three-dimensional point, using the first position; and
generating a bitstream including the first residual, the second residual, and the encoded attribute information.