Method and apparatus for encoding/decoding point cloud coordinate transformation residual
An encoding method includes: obtaining original point cloud data; transforming coordinates of the original point cloud data to obtain a coordinate transformation residual; establishing a relationship between azimuth information of a point cloud and the coordinate transformation residual; determining an encoding rule for the coordinate transformation residual based on the relationship between the azimuth information of the point cloud and the coordinate transformation residual; and encoding the coordinate transformation residual according to the encoding rule, to obtain data rate information.
1. A method for encoding a point cloud coordinate transformation residual, comprising:
obtaining original point cloud data;
transforming coordinates of the original point cloud data to obtain a coordinate transformation residual;
establishing a relationship between azimuth information of a point cloud and the coordinate transformation residual, wherein establishing the relationship between the azimuth information of the point cloud and the coordinate transformation residual comprises:
establishing function expressions between the azimuth information of the point cloud and the coordinate transformation residual as follows:
Δ
x
=
r
·
cos
(
φ
)
-
(
r
+
Δ
r
)
·
cos
(
φ
+
Δφ
)
,
and
Δ
y
=
r
·
sin
(
φ
)
-
(
r
+
Δ
r
)
·
sin
(
φ
+
Δφ
)
;
wherein Δx and Δy represent coordinate transformation residual components of a point, r represents depth information of the point, φ represents azimuth information of the point, Δr represents a precision loss of the depth information of the point, and Δφ represents a precision loss of the azimuth information of the point;
determining an encoding rule for the coordinate transformation residual based on the relationship between the azimuth information of the point cloud and the coordinate transformation residual; and
encoding the coordinate transformation residual according to the encoding rule, to obtain data rate information.
2. The method for encoding a point cloud coordinate transformation residual according to claim 1 , wherein the function expressions between the azimuth information of the point cloud and the coordinate transformation residual are approximated as follows:
Δ
x
≈
-
Δ
r
·
cos
(
φ
)
,
and
Δ
y
≈
-
Δ
r
·
sin
(
φ
)
;
wherein Δx and Δy represent coordinate transformation residual components of a point, φ represents azimuth information of the point, and Δr represents a precision loss of depth information of the point.
3. The method for encoding a point cloud coordinate transformation residual according to claim 1 , wherein establishing the relationship between the azimuth information of the point cloud and the coordinate transformation residual further comprises:
obtaining a specific representation form of an angle value of an azimuth, a function value of an azimuth, or an azimuth symbol based on a function expression of the azimuth information of the point cloud and the coordinate transformation residual.
4. The method for encoding a point cloud coordinate transformation residual according to claim 1 , wherein determining the encoding rule for the coordinate transformation residual based on the relationship between the azimuth information of the point cloud and the coordinate transformation residual comprises:
dividing an azimuth into several intervals based on the relationship between the azimuth information of the point cloud and the coordinate transformation residual; and
setting a corresponding encoding rule for the coordinate transformation residual for each azimuth interval.
5. The method for encoding a point cloud coordinate transformation residual according to claim 4 , wherein setting the corresponding encoding rule for the coordinate transformation residual for each azimuth interval comprises:
separately assigning a context model for a coordinate transformation residual of each azimuth interval, and performing corresponding initialization for entropy encoding of the coordinate transformation residual of each azimuth interval.
6. The method for encoding a point cloud coordinate transformation residual according to claim 5 , wherein encoding the coordinate transformation residual according to the encoding rule comprises:
obtaining azimuth information of a current point, and determining an azimuth interval to which the current point belongs; and
for different coordinate transformation residual components of the current point, selecting a corresponding context model based on the azimuth interval to perform entropy encoding.
7. An apparatus for encoding a point cloud coordinate transformation residual, comprising:
a computing device, configured to:
obtain original point cloud data;
transform coordinates of the original point cloud data to obtain a coordinate transformation residual;
establish a relationship between azimuth information of a point cloud and the coordinate transformation residual, wherein establishing the relationship between the azimuth information of the point cloud and the coordinate transformation residual comprises:
establishing function expressions between the azimuth information of the point cloud and the coordinate transformation residual as follows:
Δ
x
=
r
·
cos
(
φ
)
-
(
r
+
Δ
r
)
·
cos
(
φ
+
Δφ
)
,
and
Δ
y
=
r
·
sin
(
φ
)
-
(
r
+
Δ
r
)
·
sin
(
φ
+
Δφ
)
;
wherein Δx and Δy represent coordinate transformation residual components of a point, r represents depth information of the point, φ represents azimuth information of the point, Δr represents a precision loss of the depth information of the point, and Δφ represents a precision loss of the azimuth information of the point;
determine an encoding rule for the coordinate transformation residual based on the relationship between the azimuth information of the point cloud and the coordinate transformation residual; and
encode the coordinate transformation residual according to the encoding rule, to obtain data rate information.
8. A method for decoding a point cloud coordinate transformation residual, comprising:
obtaining data rate information;
determining a decoding rule for the coordinate transformation residual based on a relationship between azimuth information of a point cloud and the coordinate transformation residual, wherein the relationship between the azimuth information of the point cloud and the coordinate transformation residual comprises:
function expressions between the azimuth information of the point cloud and the coordinate transformation residual are as follows:
Δ
x
=
r
·
cos
(
φ
)
-
(
r
+
Δ
r
)
·
cos
(
φ
+
Δφ
)
,
and
Δ
y
=
r
·
sin
(
φ
)
-
(
r
+
Δ
r
)
·
sin
(
φ
+
Δφ
)
;
wherein Δx and Δy represent coordinate transformation residual components of a point, r represents depth information of the point, φ represents azimuth information of the point, Δr represents a precision loss of the depth information of the point, and Δφ represents a precision loss of the azimuth information of the point; and
decoding the data rate information according to the decoding rule, to obtain a reconstructed point cloud coordinate transformation residual.
9. An apparatus for decoding a point cloud coordinate transformation residual, comprising:
a computing device, configured to:
obtain data rate information;
determine a decoding rule for the coordinate transformation residual based on a relationship between azimuth information of a point cloud and the coordinate transformation residual, wherein the relationship between the azimuth information of the point cloud and the coordinate transformation residual comprises:
function expressions between the azimuth information of the point cloud and the coordinate transformation residual are as follows:
Δ
x
=
r
·
cos
(
φ
)
-
(
r
+
Δ
r
)
·
cos
(
φ
+
Δφ
)
,
and
Δ
y
=
r
·
sin
(
φ
)
-
(
r
+
Δ
r
)
·
sin
(
φ
+
Δφ
)
;
wherein Δx and Δy represent coordinate transformation residual components of a point, r represents depth information of the point, φ represents azimuth information of the point, Δr represents a precision loss of the depth information of the point, and Δφ represents a precision loss of the azimuth information of the point; and
decode the data rate information according to the decoding rule, to obtain a reconstructed point cloud coordinate transformation residual.
10. The apparatus for encoding a point cloud coordinate transformation residual according to claim 7 , wherein the function expressions between the azimuth information of the point cloud and the coordinate transformation residual are approximated as follows:
Δ
x
≈
-
Δ
r
·
cos
(
φ
)
,
and
Δ
y
≈
-
Δ
r
·
sin
(
φ
)
;
wherein Δx and Δy represent coordinate transformation residual components of a point, φ represents azimuth information of the point, and Δr represents a precision loss of depth information of the point.
11. The apparatus for encoding a point cloud coordinate transformation residual according to claim 7 , wherein establishing the relationship between the azimuth information of the point cloud and the coordinate transformation residual further comprises:
obtaining a specific representation form of an angle value of an azimuth, a function value of an azimuth, or an azimuth symbol based on a function expression of the azimuth information of the point cloud and the coordinate transformation residual.
12. The apparatus for encoding a point cloud coordinate transformation residual according to claim 7 , wherein determining the encoding rule for the coordinate transformation residual based on the relationship between the azimuth information of the point cloud and the coordinate transformation residual comprises:
dividing an azimuth into several intervals based on the relationship between the azimuth information of the point cloud and the coordinate transformation residual; and
setting a corresponding encoding rule for the coordinate transformation residual for each azimuth interval.
13. The apparatus for encoding a point cloud coordinate transformation residual according to claim 12 , wherein setting the corresponding encoding rule for the coordinate transformation residual for each azimuth interval comprises:
separately assigning a context model for a coordinate transformation residual of each azimuth interval, and performing corresponding initialization for entropy encoding of the coordinate transformation residual of each azimuth interval.
14. The apparatus for encoding a point cloud coordinate transformation residual according to claim 13 , wherein encoding the coordinate transformation residual according to the encoding rule comprises:
obtaining azimuth information of a current point, and determining an azimuth interval to which the current point belongs; and
for different coordinate transformation residual components of the current point, selecting a corresponding context model based on the azimuth interval to perform entropy encoding.
15. The method for decoding a point cloud coordinate transformation residual according to claim 8 , wherein the function expressions between the azimuth information of the point cloud and the coordinate transformation residual are approximated as follows:
Δ
x
≈
-
Δ
r
·
cos
(
φ
)
,
and
Δ
y
≈
-
Δ
r
·
sin
(
φ
)
;
wherein Δx and Δy represent coordinate transformation residual components of a point, φ represents azimuth information of the point, and Δr represents a precision loss of depth information of the point.
16. The apparatus for decoding a point cloud coordinate transformation residual according to claim 9 , wherein the function expressions between the azimuth information of the point cloud and the coordinate transformation residual are approximated as follows:
Δ
x
≈
-
Δ
r
·
cos
(
φ
)
,
and
Δ
y
≈
-
Δ
r
·
sin
(
φ
)
;
wherein Δx and Δy represent coordinate transformation residual components of a point, φ represents azimuth information of the point, and Δr represents a precision loss of depth information of the point.
17. The method for decoding a point cloud coordinate transformation residual, according to claim 8 , wherein determining the decoding rule for the coordinate transformation residual based on the relationship between the azimuth information of the point cloud and the coordinate transformation residual comprises:
dividing an azimuth into several intervals based on the relationship between the azimuth information of the point cloud and the coordinate transformation residual; and
setting a corresponding decoding rule for the coordinate transformation residual for each azimuth interval.
18. The apparatus for decoding a point cloud coordinate transformation residual according to claim 9 , wherein determining the decoding rule for the coordinate transformation residual based on the relationship between the azimuth information of the point cloud and the coordinate transformation residual comprises:
dividing an azimuth into several intervals based on the relationship between the azimuth information of the point cloud and the coordinate transformation residual; and
setting a corresponding decoding rule for the coordinate transformation residual for each azimuth interval.
19. The method for encoding a point cloud coordinate transformation residual according to claim 1 , wherein establishing the relationship between the azimuth information of the point cloud and the coordinate transformation residual further comprises:
obtaining a specific representation form of an angle value of an azimuth based on a function expression of the azimuth information of the point cloud and the coordinate transformation residual.
20. The method for encoding a point cloud coordinate transformation residual according to claim 1 , wherein establishing the relationship between the azimuth information of the point cloud and the coordinate transformation residual further comprises:
obtaining a specific representation form of an azimuth symbol based on a function expression of the azimuth information of the point cloud and the coordinate transformation residual.