Method and apparatus of encoding/decoding point cloud geometry data sensed by at least one sensor
A method of encoding, into a bitstream, point cloud geometry data represented by ordered coarse points occupying some discrete positions of a set of discrete positions of a two-dimensional space, includes obtaining at least one binary data (f j ) representative of an order index difference representative of a difference between order indices of two consecutive occupied coarse points and encoding each of the at least one binary data (f j ) by: obtaining coordinates (s j ,λ j ) of a current coarse point (P j ) within the two-dimensional space; obtaining a sensing number (N sens (s j ,λ j )) from the current coarse point (P j ), the sensing number (N sens (s j ,λ j )) being representative of an average number of consecutive sensing needed by a sensor (λ j ) associated with the current coarse point (P j ) to sense another coarse point; and entropy encoding, into the bitstream, the binary data (f j ) based on the sensing number (N sens (s j ,λ j )).
1 . A method of encoding, into a bitstream, point cloud geometry data represented by ordered coarse points occupying some discrete positions of a set of discrete positions of a two-dimensional space, wherein the method comprises obtaining at least one binary data (f j ) representative of an order index difference representative of a difference between order indices of two consecutive occupied coarse points and encoding each of the at least one binary data (f j ) by:
obtaining coordinates (s j ,λ j ) of a current coarse point (P j ) within the two-dimensional space;
obtaining a sensing number (N sens (s j ,λ j )) from the current coarse point (P j ), the sensing number (N sens (s j ,λ j )) being representative of an average number of consecutive sensing needed by a sensor (λ j ) associated with the current coarse point (P j ) to sense another coarse point; and
entropy encoding, into the bitstream, the binary data (f j ) based on the sensing number (N sens (s j ,λ j )).
2 . A method of decoding, from a bitstream, point cloud geometry data represented by ordered coarse points occupying some discrete positions of a set of discrete positions of a two-dimensional space, wherein the method comprises obtaining at least one binary data (f j ) representative of an order index difference representative of a difference between order indices of two consecutive occupied coarse points by:
obtaining coordinates of a current coarse point (P j ) within the two-dimensional space;
obtaining a sensing number (N sens (s j ,λ j )) from the current coarse point (P j ), the sensing number (N sens (s j ,λ j )) being representative of an average number of consecutive sensing needed by a sensor (λ j ) associated with the current coarse point (P j ) to sense another coarse point; and
entropy decoding, into the bitstream, the binary data (f j ) based on the sensing number (N sens (s j ,λ j )).
3 . The method of claim 1 , wherein entropy encoding the binary data (f j ) is based on the sensing number (N sens (s j ,λ j )) in response to the sensing number (N sens (s j , λ j )) being greater than an activation threshold (th activation ); or based on at least a coordinate difference (C j ) between one first coordinate associated with the current coarse point (P j ) and one first coordinate of a preceding encoded or decoded coarse point (P prec ) with a same sensor index as a sensor index (λ j )) associated with the current coarse point, in response to the sensing number (N sens (s j , λ j )) not being greater than the activation threshold (th activation ).
4 . The method of claim 1 , wherein entropy encoding the binary data (f j ) is based on a value (Δ j ) depending on a sample index (s j ), another sample index (s last ) associated with a sensing time instant at which a point of the point cloud, represented by a last occupied coarse point (P last ), has been sensed by the sensor associated with the sensor index (λ j ), and the sensing number (N sens (s j ,λ j )).
5 . The method of claim 4 , wherein the value (Δ j ) is bounded by two thresholds.
6 . The method of claim 1 , wherein the sensing number (N sens (s j ,λ j )) depends on at least one of a radius (r object ) or an azimuthal angle (φ last ) associated with a last occupied coarse point (P last ) representing a point of the point cloud sensed by the sensor (λ j ) associated with the current coarse point (P j ).
7 . The method of claim 1 , wherein the sensing number (N sens (s j ,λ j )) depends on a point cloud characteristic distance (L PC ), defining a mean distance between points of the point cloud, and on an arc length (L arc ) defined in a two-dimensional cartesian coordinate plane between two consecutive sensing by the sensor associated with the current coarse point.
8 . The method of claim 7 , wherein the arc length (L arc ) is based on a radius associated with a last occupied coarse point (P last ) representing a point of the point cloud sensed by the sensor associated with the current coarse point and an azimuthal shift between two consecutive sensing.
9 . The method of claim 7 , wherein the point cloud characteristic distance (L PC ) is encoded into the bitstream.
10 . An apparatus of encoding, into a bitstream, point cloud geometry data represented by ordered coarse points occupying some discrete positions of a set of discrete positions of a two-dimensional space, wherein the apparatus comprises at least one processor configured to obtain at least one binary data (f j ) representative of an order index difference representative of a difference between order indices of two consecutive occupied coarse points and encoding each of the at least one binary data (f j ) by:
obtaining coordinates (s j ,λ j ) of a current coarse point (P j ) within the two-dimensional space;
obtaining a sensing number (N sens (s j ,λ j ) from the current coarse point (P j ), the sensing number (N sens (s j ,λ j )) being representative of an average number of consecutive sensing needed by a sensor (λ j ) associated with the current coarse point (P j ) to sense another coarse point; and
entropy encoding, into the bitstream, the binary data (f j ) based on the sensing number (N sens (s j ,λ j )).
11 . An apparatus of decoding, from a bitstream, point cloud geometry data represented by ordered coarse points occupying some discrete positions of a set of discrete positions of a two-dimensional space, wherein the apparatus comprises at least one processor configured to perform the method of claim 2 .
12 . A non-transitory computer-readable storage medium carrying instructions of program code for executing the method of claim 1 .
13 . A non-transitory computer-readable storage medium carrying instructions of program code for executing the method of claim 2 .
14 . The method of claim 2 , wherein entropy decoding the binary data (f j ) is based on the sensing number (N sens (s j ,λ j )) in response to the sensing number (N sens (s j , λ j ) being greater than an activation threshold (th activation ); or based on at least a coordinate difference (C j ) between one first coordinate associated with the current coarse point (P j ) and one first coordinate of a preceding encoded or decoded coarse point (P prec ) with a same sensor index as a sensor index (λ j ) associated with the current coarse point, in response to the sensing number (N sens (s j ,λ j )) not being greater than the activation threshold (th activation ).
15 . The method of claim 2 , wherein entropy decoding the binary data (f j ) is based on a value (Δ j ) depending on a sample index (s j ), another sample index (s last ) associated with a sensing time instant at which a point of the point cloud, represented by a last occupied coarse point (P last ), has been sensed by the sensor associated with the sensor index (λ j ), and the sensing number (N sens (s j ,λ j )).
16 . The method of claim 15 , wherein the value (Δ j ) is bounded by two thresholds.
17 . The method of claim 2 , wherein the sensing number (N sens (s j ,λ j )) depends on at least one of a radius (r object ) or an azimuthal angle (P last ) associated with a last occupied coarse point (P last ) representing a point of the point cloud sensed by the sensor (λ j ) associated with the current coarse point (P j ).
18 . The method of claim 2 , wherein the sensing number (N sens (s j ,λ j )) depends on a point cloud characteristic distance (L PC ), defining a mean distance between points of the point cloud, and on an arc length (L arc ) defined in a two-dimensional cartesian coordinate plane between two consecutive sensing by the sensor associated with the current coarse point.
19 . The method of claim 18 , wherein the arc length (L arc ) is based on a radius associated with a last occupied coarse point (P last ) representing a point of the point cloud sensed by the sensor associated with the current coarse point and an azimuthal shift between two consecutive sensing.
20 . The method of claim 18 , wherein the point cloud characteristic distance (L PC ) is encoded into the bitstream.