LASER INDEX CUTTING IN PREDICTIVE GEOMETRIC CODING FOR POINT CLOUD COMPRESSION

Abstract

method and system for encoding and decoding point cloud geometry obtained from LIDAR sensors in a predictive geometry point cloud compression (G-PCC) scheme, specifically through a clipping mechanism and / or limiting the reconstructed laser index value to remain within the valid laser index range according to the number of lasers used. This invention utilizes coordinate representation in the radius, azimuth, and laser index (r, φ, i) domains, then implements laser index prediction and reconstruction by limiting or adjusting the residual laser index value during the encoding and decoding process.Thus, the reconstructed laser index does not exceed the permissible limit, thus preventing the occurrence of undefined decoder behavior, improving the reliability of the point cloud compression and decompression process, and supporting the interoperability and efficiency of LIDAR data processing in various applications such as autonomous vehicles, three-dimensional mapping, and extended reality.

Claims

Claim:

1. A method of encoding a point cloud, the method comprising: determining, by one or more processors, a plurality of lasers used to capture light detection and ranging (LIDAR) data representing the point cloud; and encoding, by the one or more processors, a laser index for a current junction of the point cloud, wherein encoding the laser index comprises: obtaining a predicted laser index value from the current junction; determining a residual laser index value for the current junction, wherein determining the residual laser index value comprises limiting the sum of the residual laser index value and the predicted laser index value based on the determined number of lasers; and encoding, in a bitstream, one or more syntax elements representing the residual laser index value.

2. The method according to claim 1, wherein limiting the sum of the residual laser index value and the predicted laser index value based on the determined number of lasers comprises: limiting the sum of the residual laser index value and the predicted laser index value to be: greater than or equal to zero and less than or equal to the determined number of lasers minus one.

3. The method according to claim 2, wherein limiting the sum of the residual laser index value and the predicted laser index value comprises truncating the sum of the residual laser index value and the predicted laser index value to be: greater than or equal to zero and less than or equal to a specified number of lasers minus one. 4 . The method according to claim 1, further comprising: encoding, in a bit-stream, syntax elements representing a specified number of lasers. 5 . The method according to claim 1, wherein the laser index coding comprises a laser index coding responsive to the determination to code the current connection using an angular coding mode of predictive geometric coding.

6. The method according to claim 1, wherein the one or more processors are included in the vehicle or head-mounted device (HMD).

7. A method of decoding a point cloud, the method comprising: determining, by one or more processors, a plurality of lasers used to capture light detection and ranging (LIDAR) data representing the point cloud; and decoding, by the one or more processors, a laser index for a current joint of the point cloud, wherein the laser index decoder comprises: obtaining a predicted laser index value of the current joint; decoding, from a bitstream, one or more syntax elements representing a residual laser index value for the current joint; and reconstructing, as a sum of the residual laser index value and the predicted laser index value, a laser index of the current joint, wherein the laser index of the current joint is limited based on a determined number of lasers.

8. The method according to claim 7, wherein the laser index of the current connection is limited to be: greater than or equal to zero and less than or equal to the specified number of lasers minus one.

9. The method according to claim 8, wherein the laser index of the current connection is limited to: greater than or equal to zero and less than or equal to the specified number of lasers minus one. 10 .The method according to claim 7, further comprising: a decoder, from a bit-stream, of syntax elements representing a predetermined number of lasers.

11. The method according to claim 7, wherein the laser index decoder comprises a laser index decoder responsive to determining that the current connection is encoded using an angular coding mode of predictive geometric coding.

12. A device for encoding a point cloud, the device comprising: a memory configured to store at least a portion of the point cloud; and one or more processors implemented in series and configured to: determine the number of lasers used to capture light detection and ranging (LIDAR) data representing the point cloud; and encode a laser index for a current connection of the point cloud, wherein, to encode the laser index, the one or more processors are configured to: obtain a predicted laser index value from the current connection; determine a residual laser index value for the current connection, wherein, to determine the residual laser index value, the one or more processors are configured to limit the sum of the residual laser index value and the predicted laser index value based on a determined quantity of lasers; and encode, in a bit stream, one or more syntactic elements representing the residual laser index value. 13 . The device according to claim 12, wherein, to limit the sum of the residual laser index value and the predicted laser index value based on the determined number of lasers, the one or more processors are configured to: limit the sum of the residual laser index value and the predicted laser index value based on the determined number of lasers to: be greater than or equal to zero and less than or equal to the determined number of lasers minus one. 14 .The device according to claim 13, wherein, to limit the sum of the residual laser index value and the predicted laser index value, the one or more processors are configured to: truncate the sum of the residual laser index value and the predicted laser index value based on the determined number of lasers to be: greater than or equal to zero and less than or equal to the determined number of lasers minus one. 15 .The device according to claim 12, wherein the one or more processors are further configured to: encode, in a bit stream, syntactic elements representing the specified number of lasers. 16 .The device according to claim 12, wherein, to encode the laser index one or more processors are configured to encode the laser index responsive to the determination to encode the current connection using an angle encoding mode of predictive geometric coding.

17. The device according to claim 12, wherein said device is a vehicle or head-mounted device (HMD).

18. A device for decoding a point cloud, the device comprising: a memory configured to store at least a portion of the point cloud; and one or more processors implemented in series and configured to: determine the number of lasers used to capture light detection and ranging (LIDAR) data representing the point cloud; and decode a laser index for a current connection of the point cloud, wherein, to decode the laser index, the one or more processors are configured to: obtain a predicted laser index value of the current connection; decode, from a bit-stream, one or more syntax elements representing a residual laser index value for the current connection; and reconstruct, as a sum of the residual laser index value and the predicted laser index value, a laser index of the current connection, wherein the laser index of the current connection is limited by a determined number of lasers. 19 .The device according to claim 18, wherein the laser index of the current connection is limited to be: greater than or equal to zero and less than or equal to the specified number of lasers minus one. 20 .The device according to claim 19, wherein the laser index of the current connection is limited to: greater than or equal to zero and less than or equal to the specified number of lasers minus one. 21 .The device of claim 18, wherein the one or more processors are further configured to: decode, from the bit-stream, syntax elements representing the specified number of lasers.

22. The device of claim 18, wherein, to decode the laser index, the one or more processors are configured to decode the laser index responsive to determining that the current connection is encoded using an angle encoding mode of predictive geometric coding.

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