CN112565764B - A method for inter-frame encoding and decoding of point cloud geometric information - Google Patents

Abstract

The embodiment of the invention provides a point cloud geometric information interframe coding and decoding method, which comprises the steps of obtaining a frame point cloud before a current frame point cloud as a reference frame point cloud; respectively carrying out octree division on the current frame point cloud and the reference frame point cloud, then dividing the divided nodes, and obtaining a first octree structure of the current frame point cloud and a second octree structure of the reference frame point cloud after iterative division to leaf nodes; acquiring the occupancy condition of each reference node, and acquiring the occupancy condition of a first neighbor node of the reference node when the occupancy condition of the reference node corresponding to the coding node is occupied; and determining a context model of the occupation code of the node to be coded based on the occupation situation and carrying out entropy coding according to the context model to obtain a binary code stream. The invention uses the context model of the interframe to carry out entropy coding when the interframe prediction occupies, otherwise uses the context model of the intraframe to carry out entropy coding without motion compensation, thereby reducing the complexity of interframe coding and decoding and improving the performance of geometric entropy coding.

Description

A method for inter-frame encoding and decoding of point cloud geometric information

technical field

The invention belongs to the technical field of encoding and decoding, and in particular relates to a method for inter-frame encoding and decoding of point cloud geometric information.

Background technique

With the continuous development of point cloud technology, the compression coding of point cloud data has become an important research problem. At present, both the Audio Video coding Standard Workgroup of China (AVS, Audio Video coding Standard Workgroup of China) and the Moving Picture Experts Group (MPEG, Moving Picture Experts Group) in the International Organization for Standardization are formulating standards for point cloud coding. At this stage, the point cloud encoding process of AVS is shown in Figure 1. First, coordinate transformation is performed on the geometric information, so that all point clouds are contained in a bounding box (bounding box). Then quantization is carried out. This step of quantization mainly plays the role of scaling. Due to the rounding of quantization, the geometric information of some points is the same, and whether to remove duplicate points is determined according to the parameters. The process of quantization and removal of duplicate points is also called for voxelization. The bounding box is called the root node, and the octree division of the root node is to divide the bounding box into eight sub-cubes. Whether it is occupied means whether it contains a point in the point cloud. 0 means that the child node is not occupied, and 1 means that the child node is occupied. This bit is called the occupancy code, and is entropy encoded to generate a binary code stream. Continue to perform octree division on non-empty sub-cubes (including points in the point cloud) until the divided leaf nodes are 1x1x1 unit cubes, and stop dividing. The point in the point is encoded to generate a binary code stream. After the geometry encoding is completed, the geometry information is reconstructed. The encoding of attribute information is mainly carried out for color information. First, convert the color information from RGB color space to YUV color space. The geometrically reconstructed point cloud is then recolored using the original point cloud so that the unencoded attribute information corresponds to the reconstructed geometric information. In the color information coding, after the point cloud is sorted by Morton code, the nearest neighbor of the point to be predicted is searched by using the geometric space relationship, and the predicted attribute value is obtained by interpolation prediction of the point to be predicted by using the reconstructed attribute value of the found neighbor, and then the predicted attribute value is obtained. The prediction residual is obtained by differentiating the real attribute value and the predicted attribute value, and finally the prediction residual is quantized and encoded to generate a binary code stream. The decoding process is shown in Figure 2, and the decoding process and the encoding process are inverse to each other.

In the current AVS point cloud coding platform, there is no inter-frame technology, only the above-mentioned intra-frame technology, so only the spatial correlation can be used to remove redundant information, and the temporal correlation cannot be used to remove redundant information.

SUMMARY OF THE INVENTION

In order to solve the above problems existing in the prior art, the present invention provides an inter-frame encoding and decoding method for point cloud geometric information. The technical problem to be solved by the present invention is realized by the following technical solutions:

In a first aspect, a method for inter-frame coding of point cloud geometric information provided by the present invention includes:

Obtain the frame point cloud before the current frame point cloud as the reference frame point cloud of the current frame point cloud;

Perform voxelization on the point cloud of the current frame to obtain the point cloud of the current frame after voxelization;

The current frame point cloud and the reference frame point cloud are divided into octrees respectively, and the divided sub-nodes are divided into octrees until they are divided into leaf nodes, and the first octree structure and reference of the current frame point cloud are obtained. The second octree structure of the frame point cloud;

Wherein, the first octree structure includes a plurality of nodes, and each node corresponds to a reference node in the second octree structure;

For each node to be encoded in the first octree structure, obtain the occupancy situation of the corresponding reference node in the second octree structure;

For each node to be coded in the first octree structure, when the occupancy situation of the reference node corresponding to the node to be coded is occupied, obtain the occupancy situation of the first neighbor node adjacent to the reference node;

Based on the occupancy situation of the first neighbor node, determine the context model of the occupancy code of the node to be encoded;

Entropy encoding is performed on the node occupancy code to be encoded after the context model is determined to obtain a binary code stream.

Optionally, for each node to be encoded in the first octree structure, when the occupancy status of the reference node corresponding to the node to be encoded is occupied, obtain the first neighbor node adjacent to the reference node. The steps for a placeholder situation include:

For each node to be coded in the first octree structure, when the occupancy status of the reference node corresponding to the to-be-coded node is occupied, the occupancy status of the first neighbor node coplanar with the reference node is acquired.

Optionally, at each node to be encoded for the first octree structure, when the occupancy status of the reference node corresponding to the node to be encoded is occupied, obtain the first neighbor adjacent to the reference node. Before the step of the node, the method for inter-frame encoding of point cloud geometric information further includes:

For each node to be encoded in the first octree structure, determine whether the reference node corresponding to the node to be encoded is occupied; The occupancy of any or combination of the second neighbor nodes in the parent node coplanarity;

Based on the occupancy situation of the second neighbor node, the context model of the occupancy code of the node to be encoded is determined.

Optionally, before the step of determining the context model of the occupancy code of the node to be encoded based on the occupancy situation of the first neighbor node, the method for inter-frame coding of point cloud geometric information further includes:

Obtain the occupancy status of the second neighbor node that is coplanar, collinear, co-point with the node to be encoded, and coplanar with the parent node of the node to be encoded or combined;

The step of determining the context model of the occupancy code of the node to be encoded based on the occupancy situation of the first neighbor node includes:

Based on the occupancy conditions of the first neighbor node and the second neighbor node, a context model of the occupancy code of the node to be encoded is determined.

Optionally, before the step of determining the context model of the occupancy code of the node to be encoded based on the occupancy situation of the first neighbor node, the method for inter-frame coding of point cloud geometric information further includes:

Obtain the occupancy status of the third neighbor node that is coplanar, colinear, and copointed with the reference node corresponding to the node to be encoded;

forming a set of the occupancy conditions of the third neighbor nodes;

Selecting a first preset number of elements in the set as target elements;

The step of determining the context model of the occupancy code of the node to be encoded based on the occupancy situation of the first neighbor node includes:

Based on the target element, a context model of the placeholder code of the node to be encoded is determined.

Optionally, after the step of selecting a preset number of elements in the set as target elements, the method for inter-frame coding of point cloud geometric information further includes:

Optionally select a second preset number of elements in the target elements, and use the second preset number of elements as elements for determining the same context model;

Wherein, the first preset number is greater than the second preset number;

Based on the target element, the step of determining the context model of the placeholder code of the node to be encoded includes:

Based on the second number of elements in the target element, a context model of the placeholder code of the node to be encoded is determined.

Optionally, after the step of acquiring the occupancy status of the first neighbor node coplanar with the reference node, the method for inter-frame encoding of point cloud geometric information further includes:

obtaining the location information of the first neighbor node;

Based on the occupancy situation of the first neighbor node, the step of determining the context model of the occupancy code of the node to be encoded includes:

Based on the location information and occupancy status of the first neighbor node, a context model of the occupancy code of the node to be encoded is determined.

In a second aspect, a method for inter-frame decoding of point cloud geometric information provided by the present invention includes:

receive binary stream;

Wherein, the binary code stream includes the node occupancy code to be decoded;

For each node to be decoded, when the occupancy situation of the reference node corresponding to the node to be decoded is occupied, obtain the occupancy situation of the first neighbor node adjacent to the reference node;

determining the context model of the occupancy code of the node to be decoded based on the occupancy situation of the first neighbor node;

Entropy decoding is performed on the node occupancy code to be decoded after the context model is determined.

Optionally, for each node to be decoded in the first octree structure, when the occupancy status of the reference node corresponding to the node to be decoded is occupied, obtain the first neighbor node adjacent to the reference node. The steps for a placeholder situation include:

For each node to be decoded in the first octree structure, when the occupancy status of the reference node corresponding to the to-be-decoded node is occupied, the occupancy status of the first neighbor node coplanar with the reference node is acquired.

Optionally, at each node to be decoded for the first octree structure, when the occupancy status of the reference node corresponding to the node to be decoded is occupied, obtain the first neighbor adjacent to the reference node. Before the step of the node, the method for inter-frame decoding of point cloud geometric information further includes:

Determine whether the reference node corresponding to the node to be decoded is occupied, if not, obtain the second neighbor node that is coplanar, collinear, co-point with the node to be decoded, and coplanar with the parent node of the node to be decoded or combined occupancy;

Based on the occupancy situation of the second neighbor node, the context model of the occupancy code of the node to be decoded is determined.

An embodiment of the present invention provides a method for inter-frame encoding of point cloud geometric information. By acquiring the frame point cloud before the current frame point cloud as the reference frame point cloud; the current frame point cloud and the reference frame point cloud are divided into octrees respectively. , and then divide the divided nodes, iteratively divide to the end of the leaf node, and obtain the first octree structure of the point cloud of the current frame and the second octree structure of the point cloud of the reference frame; obtain the occupancy of each reference node situation; when the occupancy situation of the reference node corresponding to the coding node is occupied, obtain the occupancy situation of the first neighbor node of the reference node; based on the occupancy situation, determine the context model of the occupancy code of the node to be encoded and Entropy coding is performed according to the context model to obtain a binary code stream. In the present invention, the inter-frame context model is used for entropy coding when the inter-frame prediction is occupied, otherwise, the intra-frame context model is used for entropy coding without motion compensation, so the complexity of inter-frame coding and decoding can be reduced and the geometric entropy coding performance can be improved. .

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

Description of drawings

1 is a schematic flowchart of an AVS encoding process provided by an embodiment of the present invention;

2 is a schematic diagram of an AVS decoding process provided by an embodiment of the present invention;

FIG. 3 is a flowchart of the application of the inter-frame technology provided by an embodiment of the present invention to an AVS encoding process;

FIG. 4 is a flowchart of the application of the inter-frame technology provided by an embodiment of the present invention to an AVS decoding process;

5 is a flowchart of a method for inter-frame encoding of point cloud geometric information provided by an embodiment of the present invention;

6 is a schematic diagram of a neighbor node of a reference frame corresponding node;

7 is a flowchart of an AVS inter-frame prediction provided by an embodiment of the present invention;

8 is a schematic diagram of 6 coplanar neighbor nodes existing in a reference node according to an embodiment of the present invention;

9 is a schematic diagram of 12 collinear neighbor nodes existing in a reference node provided by an embodiment of the present invention;

10 is a schematic diagram of 8 common-point neighbor nodes existing in a reference node provided by an embodiment of the present invention;

FIG. 11 is a flowchart of a method for inter-frame decoding of point cloud geometric information according to an embodiment of the present invention.

Detailed ways

The present invention will be described in further detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

Example 1

Referring to FIG. 3, in the process of AVS encoding, the inter-frame technology is used, so that a method for inter-frame encoding of point cloud geometric information provided by an embodiment of the present invention is used. .

As shown in FIG. 4 , a method for inter-frame coding of point cloud geometric information provided by an embodiment of the present invention includes:

S1a, obtaining the frame point cloud before the current frame point cloud as the reference frame point cloud of the current frame point cloud;

The frame point cloud before the current frame point cloud may be the previous frame point cloud of the current frame point cloud, or a frame in the previous N frame point clouds, which is not limited in the present invention.

S2a, perform voxelization processing on the point cloud of the current frame to obtain the point cloud of the current frame after voxelization processing;

S3a, perform octree division on the point cloud of the current frame and the point cloud of the reference frame respectively, and continue to perform octree division on the sub-nodes obtained by division until the leaf nodes are divided to obtain the first octree structure of the point cloud of the current frame and the second octree structure of the reference frame point cloud;

Wherein, the first octree structure includes a plurality of nodes, and each node corresponds to a reference node in the second octree structure;

S4a, for each node to be encoded in the first octree structure, obtain the occupancy situation of the corresponding reference node in the second octree structure;

S5a, for each node to be coded in the first octree structure, when the occupancy situation of the reference node corresponding to the node to be coded is occupied, obtain the occupancy situation of the first neighbor node adjacent to the reference node ;

Referring to Figure 5, the left side of Figure 5 is the reference frame, the right side of Figure 5 is the current frame, the node to be encoded in the current frame is a gray block, the reference node corresponding to the node to be encoded in the reference frame is also a gray block, and the blank block is the first. a neighbor node.

S6a, based on the occupancy situation of the first neighbor node, determine the context model of the occupancy code of the node to be encoded;

S7a, entropy encoding is performed on the node occupancy code to be encoded after the context model is determined to obtain a binary code stream.

As an optional implementation manner of the present invention, after the binary code stream is obtained, the probability distribution corresponding to the allocated context model of the occupancy code of the node to be encoded may be updated.

It can be understood that the probability distribution corresponding to the context may change after each context is allocated. Therefore, updating the probability distribution of the context can improve the accuracy of allocating the context to the node occupancy code to be coded, thereby improving the coding performance.

Referring to Figure 6, the execution process can be:

(1) First, a part of the memory can be opened to save the reconstructed point cloud obtained from the previous frame as the reference frame of the point cloud of the current frame, which is recorded as pointcloudPred;

(2) Quantize the current frame point cloud pointcloud to obtain the current frame quantized point cloud and record it as pointcloudQua;

(3) The quantized point cloud pointcloudQua of the current frame and the point cloudPred of the reference frame are divided into octrees respectively, and the occupancy codes of the octrees are respectively recorded as occupancy and occupancyPred, and each bit of the 8-bit occupancy code is respectively recorded as Oi and OPi, and store the 8-bit occupancy codes of the current point cloud and the reference point cloud in the hash table, which is convenient for finding neighbor information for the node later.

(4) Determine whether the current node satisfies the outlier coding scheme. If it satisfies the outlier coding scheme, directly set the occupancy to 0, enter (5) coding the occupancy, and then encode the relative coordinates of the outliers. If the outlier coding scheme is not satisfied, directly Enter (5).

(5) If OPi is equal to 1, that is, the ith child node of the current block of the reference frame is occupied, then find the occupancy information of the reference frame node (as shown in Figure 4) corresponding to the coded coplanar neighbor node of the current child node Oi, and calculate The sum of the occupied neighbor nodes is 0-3, a total of 4 cases, the corresponding 4 contexts are assumed to be ctx_interPredict[4], each context corresponds to a probability distribution, and the probability distribution corresponding to the context is selected by using the occupancy of the neighbor nodes. The selected probability distribution performs entropy encoding on the occupancy code Oi of the ith child node of the current block of the current frame, and updates the probability distribution corresponding to the selected context based on Oi; if OPi is equal to 0, that is, the ith child of the current block of the reference frame is used. If the node is not occupied, then use the 191 contexts in the original frame to entropy encode the occupancy code Oi of the i-th child node of the current block of the current frame. One of the contexts corresponds to a probability distribution, and the probability corresponding to the selected context is based on Oi. The distribution is updated.

An embodiment of the present invention provides a method for inter-frame encoding of point cloud geometric information. By acquiring the frame point cloud before the current frame point cloud as the reference frame point cloud; the current frame point cloud and the reference frame point cloud are divided into octrees respectively. , and then divide the divided nodes, iteratively divide to the end of the leaf node, and obtain the first octree structure of the point cloud of the current frame and the second octree structure of the point cloud of the reference frame; obtain the occupancy of each reference node situation; when the occupancy situation of the reference node corresponding to the coding node is occupied, obtain the occupancy situation of the first neighbor node of the reference node; based on the occupancy situation, determine the context model of the occupancy code of the node to be encoded and Entropy coding is performed according to the context model to obtain a binary code stream. In the present invention, the inter-frame context model is used for entropy coding when the inter-frame prediction is occupied, otherwise, the intra-frame context model is used for entropy coding without motion compensation, so the complexity of inter-frame coding and decoding can be reduced and the geometric entropy coding performance can be improved. .

Embodiment 2

As an optional embodiment of the present invention, for each to-be-coded node of the first octree structure, when the occupancy status of the reference node corresponding to the to-be-coded node is occupied, obtain and reference node The steps of the occupancy situation of the adjacent first neighbor nodes include:

For each node to be coded in the first octree structure, when the occupancy status of the reference node corresponding to the to-be-coded node is occupied, the occupancy status of the first neighbor node coplanar with the reference node is acquired.

Embodiment 3

As an optional embodiment of the present invention, for each to-be-coded node of the first octree structure, when the occupancy status of the reference node corresponding to the to-be-coded node is occupied, obtain and reference Before the step of the first neighbor node adjacent to the node, the method for inter-frame coding of point cloud geometric information further includes:

Step a: for each node to be encoded in the first octree structure, determine whether the reference node corresponding to the node to be encoded is occupied, if not, obtain coplanar, collinear, common point and the node to be encoded The occupancy situation of any one or a combination of the second neighbor nodes in the coplanar parent node of the encoding node;

Step b: Determine the context model of the occupancy code of the node to be encoded based on the occupancy situation of the second neighbor node.

Embodiment 4

As an optional embodiment of the present invention, before the step of determining the context model of the occupancy code of the node to be encoded based on the occupancy status of the first neighbor node, the point cloud geometric information Coding methods also include:

Obtain the occupancy status of the second neighbor node that is coplanar, collinear, co-point with the node to be encoded, and coplanar with the parent node of the node to be encoded or combined;

The step of determining the context model of the occupancy code of the node to be encoded based on the occupancy situation of the first neighbor node includes:

Based on the occupancy conditions of the first neighbor node and the second neighbor node, a context model of the occupancy code of the node to be encoded is determined.

It can be understood that in this embodiment, the intra-frame and inter-frame are no longer used separately, but the context of the intra-frame and inter-frame is used in combination, which can be combined into context[intracontext][intercontext] or context[intercontext][intracontext], considering both Intra-frame information also considers inter-frame information. In the above inter-frame scheme, there are 4 contexts between frames and 191 contexts within a frame, so there are 4*191=764 contexts.

Embodiment 5

As an optional embodiment of the present invention, before the step of determining the context model of the occupancy code of the node to be encoded based on the occupancy status of the first neighbor node, the point cloud geometric information Coding methods also include:

Step a: Obtain the occupancy status of the third neighbor node that is coplanar, colinear, and co-pointed with the reference node corresponding to the node to be encoded;

Step b: forming a set of the occupancy conditions of the third neighbor nodes;

Step c: Optionally select a preset number of elements as target elements in the set;

Step d: The step of determining the context model of the occupancy code of the node to be encoded based on the occupancy situation of the first neighbor node includes:

Step e: Based on the target element, determine the context model of the placeholder code of the node to be encoded.

As shown in Fig. 7 to Fig. 9 , the reference node has 6 coplanar neighbors, 12 collinear neighbors and 8 coplanar neighbors. This embodiment changes the way of finding neighbors, not just finding the current child node Oi that has been coded coplanar nodes The corresponding reference frame node. Since all the information between frames can be obtained at the encoding and decoding ends, it is possible to find all the coplanar, collinear and common points of OPi corresponding to the Oi node, a total of 26 neighbor nodes or a subset of these 26 neighbor nodes.

Embodiment 6

As an optional embodiment of the present invention, after the step of selecting a preset number of elements in the set as target elements, the method for inter-frame encoding of point cloud geometric information further includes:

Optionally select a second preset number of elements in the target elements, and use the second preset number of elements as elements for determining the same context model;

Wherein, the first preset number is greater than the second preset number;

Based on the target element, the step of determining the context model of the placeholder code of the node to be encoded includes:

Based on the second number of elements in the target element, a context model of the placeholder code of the node to be encoded is determined.

It can be understood that the step (5) in the embodiment is modified, and the number of nodes occupied and mapped are no longer the number of occupied nodes and a corresponding context, but the number of occupied nodes can be mapped to the sum of the corresponding context. Corresponding to a context, for example, when the number of occupied neighbors in the main scheme is 1 and 2, the same context is used, then one context can be reduced and only 3 contexts are used.

Embodiment 7

As an optional embodiment of the present invention, after the step of acquiring the occupancy status of the first neighbor node that is coplanar with the reference node, the method for inter-frame encoding of point cloud geometric information further includes:

obtaining the location information of the first neighbor node;

Based on the occupancy situation of the first neighbor node, the step of determining the context model of the occupancy code of the node to be encoded includes:

Based on the location information and occupancy status of the first neighbor node, a context model of the occupancy code of the node to be encoded is determined.

It can be understood that the occupancy status is occupied or unoccupied, and the position information includes the position of the first neighbor node relative to the reference node. The occupancy status and the position information are arranged and combined, and the number of context models is expanded to a geometric multiple.

The advantages of the encoding method provided by the present invention are verified below with experimental data. Without changing the geometric PSNR (PSNR is an objective standard for image evaluation, the larger the PSNR, the better the image quality.), the encoding code stream size can be reduced, as shown in the table below, the reconstructed point cloud is in C1 (geometric BD-rate in the case of lossy, attribute lossy) (BD-rate is a parameter used to measure the quality of performance. When BD-rate is negative, it means that the performance becomes better. On this basis, the absolute value of BD-rate is higher. Larger, the greater the gain in performance.) The performance becomes better, in the case of C4 (geometric lossless, attribute lossless) bpp (bpp is used to measure the size of the code stream in the lossless case, less than 100% means the performance becomes better, in On this basis, the smaller the absolute value, the larger the gain) and the better the performance. On the AVS platform, the geometric information of some multi-frame point cloud sequences is tested under the conditions of C1 (geometric lossy, attribute lossy) and C4 (geometric lossless, attribute lossless), and the results are shown in Table 1 and Table 2:

Table 1 The performance comparison result of the coding method of the present invention and the existing AVS point cloud coding technology in the case of C1

Table 2 The performance comparison results of the coding method of the present invention and the existing AVS point cloud coding technology in the case of C4

sequence name bpp ford_01 97.1% ford_02 98.0% ford_03 98.7%

Embodiment 8

Referring to FIG. 10 , in the process of AVS decoding, the inter-frame technology is used to obtain an inter-frame decoding method for point cloud geometric information provided by an embodiment of the present invention.

As shown in FIG. 11 , an inter-frame decoding method for point cloud geometric information provided by an embodiment of the present invention includes:

S1b, receive binary code stream;

Wherein, the binary code stream includes the node occupancy code to be decoded;

S2b, for each node to be decoded, when the occupancy situation of the reference node corresponding to the node to be decoded is occupied, obtain the occupancy situation of the first neighbor node adjacent to the reference node;

S3b, based on the occupancy situation of the first neighbor node, determine the context model of the occupancy code of the node to be decoded;

S4b, entropy decoding is performed on the node occupancy code to be decoded after the context model is determined.

Embodiment 9

As an optional embodiment of the present invention, for each node to be decoded in the first octree structure, when the occupancy status of the reference node corresponding to the node to be decoded is occupied, obtain the reference node The steps of the occupancy situation of the adjacent first neighbor nodes include:

For each node to be decoded in the first octree structure, when the occupancy status of the reference node corresponding to the to-be-decoded node is occupied, the occupancy status of the first neighbor node coplanar with the reference node is acquired.

Embodiment ten

As an optional embodiment of the present invention, for each node to be decoded in the first octree structure, when the occupancy status of the reference node corresponding to the node to be decoded is occupied, obtain and reference Before the step of the neighbor node adjacent to the node, the method for inter-frame decoding of point cloud geometric information further includes:

Step a: Determine whether the reference node corresponding to the node to be decoded is occupied, and if not, obtain any or a combination of the nodes that are coplanar, collinear, co-point with the node to be decoded, and coplanar with the parent node of the node to be decoded. Occupancy of two neighbor nodes;

Step b: Determine the context model of the occupancy code of the node to be decoded based on the occupancy situation of the second neighbor node.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deductions or substitutions can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (10)

1. A point cloud geometric information interframe coding method is characterized by comprising the following steps:

acquiring a frame point cloud before a current frame point cloud as a reference frame point cloud of the current frame point cloud;

performing voxelization processing on the current frame point cloud to obtain the voxelized current frame point cloud;

respectively carrying out octree division on the current frame point cloud and the reference frame point cloud, and continuously carrying out octree division on sub nodes obtained by division until leaf nodes are divided to obtain a first octree structure of the current frame point cloud and a second octree structure of the reference frame point cloud;

wherein the first octree structure comprises a plurality of nodes, each node corresponding to a reference node in the second octree structure;

aiming at each node to be coded in the first octree structure, acquiring the occupation situation of a corresponding reference node in the second octree structure;

for each node to be coded of the first octree structure, when the occupation situation of a reference node corresponding to the node to be coded is occupied, acquiring the occupation situation of a first neighbor node adjacent to the reference node;

determining a context model of the bit occupying code of the node to be coded based on the bit occupying situation of the first neighbor node;

and entropy coding the placeholder code of the node to be coded after the context model is determined to obtain a binary code stream.

2. The point cloud geometric information interframe coding method according to claim 1, wherein the step of acquiring, for each node to be coded of the first octree structure, an occupancy of a first neighbor node adjacent to a reference node when an occupancy of the reference node corresponding to the node to be coded is occupied comprises:

for each node to be coded of the first octree structure, when the occupancy condition of a reference node corresponding to the node to be coded is occupied, the occupancy condition of a first neighbor node coplanar with the reference node is obtained.

3. The point cloud geometric information interframe coding method according to claim 1, wherein before the step of obtaining, for each node to be coded of the first octree structure, a first neighboring node adjacent to a reference node when an occupancy of the reference node corresponding to the node to be coded is occupied, the point cloud geometric information interframe coding method further comprises:

judging whether a reference node corresponding to a node to be coded is occupied or not aiming at each node to be coded of the first octree structure, if not, acquiring the occupation condition of a second neighbor node which is any one or combination of coplanarity, collinearity and coplanarity with the node to be coded and coplanarity with a father node of the node to be coded;

and determining a context model of the bit occupying code of the node to be coded based on the bit occupying situation of the second neighbor node.

4. The point cloud geometric information interframe coding method according to claim 1, wherein before the step of determining the context model of the node-to-be-coded space-occupying code based on the space-occupying condition of the first neighboring node, the point cloud geometric information interframe coding method further comprises:

acquiring the occupation situation of a second neighbor node which is coplanar, collinear or concurrent with the node to be coded and is coplanar or combined with a father node of the node to be coded;

the step of determining the context model of the node occupation code to be coded based on the occupation situation of the first neighbor node comprises:

and determining a context model of the node occupation code to be coded based on occupation conditions of the first neighbor node and the second neighbor node.

5. The point cloud geometry information interframe coding method of claim 1, wherein prior to the step of determining the context model of the node-to-be-coded placeholder code based on the placeholder of the first neighboring node, the point cloud geometry information interframe coding method further comprises:

acquiring the occupation situation of a third neighbor node which is coplanar, collinear and concurrent with the reference node corresponding to the node to be coded;

forming a set of the occupation conditions of the third neighbor nodes;

optionally selecting a first preset number of elements in the set as target elements;

the step of determining the context model of the node occupancy code to be coded based on the occupancy of the first neighboring node comprises:

and determining a context model of the node occupation code to be coded based on the target element.

6. The point cloud geometric information interframe coding method according to claim 5, wherein after the step of optionally selecting a preset number of elements in the set as target elements, the point cloud geometric information interframe coding method further comprises:

optionally selecting a second preset number of elements from the target elements, and taking the second preset number of elements as elements for determining the same context model;

the first preset quantity is greater than the second preset quantity;

the step of determining the context model of the node occupation code to be coded based on the target element comprises the following steps:

determining a context model of the node-to-be-encoded bit-occupying code based on a second number of target elements.

7. The point cloud geometry information interframe coding method of claim 2, wherein after the step of obtaining an occupancy of a first neighbor node that is coplanar with a reference node, the point cloud geometry information interframe coding method further comprises:

acquiring the position information of the first neighbor node;

the step of determining the context model of the node-occupying code to be coded based on the occupying situation of the first neighboring node comprises:

and determining a context model of the occupation code of the node to be coded based on the position information and the occupation situation of the first neighbor node.

8. A point cloud geometric information interframe decoding method is characterized by comprising the following steps:

receiving a binary code stream;

the binary code stream comprises a node occupation code to be decoded;

for each node to be decoded of the first octree structure, when the occupation situation of a reference node corresponding to the node to be decoded is occupied, acquiring the occupation situation of a first neighbor node adjacent to the reference node;

determining a context model of the node occupation code to be decoded based on the occupation situation of the first neighbor node;

and entropy decoding the placeholder of the node to be decoded after the context model is determined.

9. The point cloud geometric information interframe decoding method of claim 8, wherein the step of obtaining, for each node to be decoded of the first octree structure, an occupancy of a first neighbor node adjacent to a reference node when an occupancy of the reference node corresponding to the node to be decoded is occupied comprises:

for each node to be decoded of the first octree structure, when the occupancy of the reference node corresponding to the node to be decoded is occupied, acquiring the occupancy of a first neighbor node coplanar with the reference node.

10. The point cloud geometric information interframe decoding method according to claim 8, wherein before the step of acquiring, for each node to be decoded of the first octree structure, a first neighbor node adjacent to a reference node when an occupancy of the reference node corresponding to the node to be decoded is occupied, the point cloud geometric information interframe decoding method further comprises:

judging whether a reference node corresponding to a node to be decoded is occupied, if not, acquiring the occupation condition of a second neighbor node which is any one or combination of coplanarity, collinearity and coplanarity with the node to be decoded and coplanarity with a father node of the node to be decoded;

and determining a context model of the occupation code of the node to be decoded based on the occupation situation of the second neighbor node.

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