Method and device for up-sampling a point cloud
This method for up-sampling a point cloud representing a 3D object, comprises: —detecting ( 2 ) points belonging to at least one under-sampled region of the point cloud on the basis of at least one desirable sampling rate (K); —obtaining ( 12 ), for each detected point, an associated tangent plane; —inserting ( 14 ) in the point cloud at least one neighboring point of each detected point if a distance between the neighboring point and the tangent plane associated with the detected point is less than a first threshold.
1. A method comprising:
detecting a plurality of points of a point cloud, wherein a detected point has a number of distance-S neighbors being less than a first value and a number of distance-S′ neighbors being greater than a second value, wherein S′ is larger than S;
obtaining, for the plurality of detected points, associated planes; and
inserting in the point cloud at least one neighboring point for each of the plurality of detected points based on a distance between the neighboring point and the plane associated with the detected point.
2. The method of claim 1 , wherein the plurality of points of a point cloud are detected on a basis of at least one sampling rate, and wherein the at least one sampling rate is defined as a minimum number of neighbors of each point of the point cloud in a sphere or a cube whose center is the point and having a given size.
3. The method of claim 1 , wherein it is decided whether the neighboring point is inserted depending on one or more of:
the number of the distance-S neighbors; or
a change of a distance between a further neighborhood defined by the distance S′ and a local neighborhood defined by the distance S of the detected point when the neighboring point is inserted.
4. The method of claim 1 , wherein the plane associated with the detected point is determined using a Principal Component Analysis (PCA) technique.
5. The method of claim 1 , further comprising determining an attribute of each inserted point.
6. The method of claim 5 , wherein the attribute is a color.
7. The method of claim 5 , wherein the attribute is determined by interpolation from nearby points of the point cloud.
8. The method of claim 7 , wherein the interpolation is performed in a R, G, B color space or in a Y, U, V color space.
9. A method for coding a point cloud representing a 3D object, comprising an up-sampling post-processing according to claim 1 .
10. A method for decoding, from a bitstream, a point cloud representing a 3D object, comprising an up-sampling post-processing according to claim 1 .
11. An apparatus comprising a memory and one or more processors configured to:
detect a plurality of points of a point cloud, wherein a detected point has a number of distance-S neighbors being less than a first value and a number of distance-S′ neighbors being greater than a second value, wherein S′ is larger than S;
obtain, for the plurality of detected points, associated planes; and
insert in the point cloud at least one neighboring point for each of the plurality of detected points based on a distance between the neighboring point and the plane associated with the detected point.
12. The apparatus of claim 11 , wherein the plurality of points of a point cloud are detected on a basis of at least one sampling rate, and wherein the at least one sampling rate is defined as a minimum number of neighbors of each point of the point cloud in a sphere or a cube whose center is the point and having a given size.
13. The apparatus of claim 11 , wherein it is decided whether the neighboring point is inserted depending on one or more of:
the number of the distance-S neighbors; or
a change of a distance between a further neighborhood defined by the distance S′ and a local neighborhood defined by the distance S of the detected point when the neighboring point is inserted.
14. The apparatus of claim 11 , wherein the plane associated with the detected point is determined using a Principal Component Analysis (PCA) technique.
15. The apparatus of claim 11 , wherein the one or more processors are further configured to determine an attribute of each inserted point.
16. The apparatus of claim 15 , wherein the attribute is a color.
17. The apparatus of claim 15 , wherein the attribute is determined by interpolation from nearby points of the point cloud.
18. The apparatus of claim 17 , wherein the interpolation is performed in a R, G, B color space or in a Y, U, V color space.
19. An encoder comprising the apparatus of claim 11 .
20. A decoder comprising the apparatus of claim 11 .