EP-4742162-A1 - DECODING METHOD, DECODING DEVICE, AND ENCODING DEVICE

Abstract

A decoding method includes: in a first prediction process performed when a depth of a current node that stores a three-dimensional point is less than a first threshold value, prioritizing inter prediction over intra prediction (S501); in a second prediction process performed when the depth is less than a second threshold value and less than or equal to the first threshold value, using a prediction scheme indicated in control information included in a bitstream, the second threshold value being greater than the first threshold value (S502); and in a third prediction process performed when the depth is less than or equal to the second threshold value, using the intra prediction (S503). For example, in at least one of the first prediction process, the second prediction process, or the third prediction process, both the intra prediction and the inter prediction need not be used under a predetermined condition.

Inventors

• OHKAWA, MASATO
• IGUCHI, NORITAKA
• SUGIO, TOSHIYASU
• NISHI, TAKAHIRO
• ITO, ATSUSHI

Assignees

• Panasonic Intellectual Property Corporation of America

Dates

Publication Date

20260513

Application Date

20240521

Claims (7)

1. A decoding method comprising: in a first prediction process performed when a depth of a current node that stores a three-dimensional point is less than a first threshold value, prioritizing inter prediction over intra prediction; in a second prediction process performed when the depth is less than a second threshold value and less than or equal to the first threshold value, using a prediction scheme indicated in control information included in a bitstream, the second threshold value being greater than the first threshold value; and in a third prediction process performed when the depth is less than or equal to the second threshold value, using the intra prediction.
2. The decoding method according to claim 1, wherein in at least one of the first prediction process, the second prediction process, or the third prediction process, both the intra prediction and the inter prediction are not to be used under a predetermined condition.
3. The decoding method according to claim 1, further comprising: determining a prediction process to be used for the current node, by using first information that is included in the bitstream and indicates the first threshold value and the second threshold value.
4. The decoding method according to claim 3, wherein the first information includes: second information indicating an ordinal level of the first threshold value from a shallowest depth, and third information indicating an ordinal level of the second threshold value from a deepest depth.
5. The decoding method according to claim 1, wherein the control information includes a first flag for the current node for which the second prediction process is to be used, when the first flag indicates a first value: the control information further includes a second flag for the current node; when the second flag indicates a third value, the intra prediction is to be used in a prediction process for the current node; and when the second flag indicates a fourth value, both the inter prediction and the intra prediction are not to be used in the prediction process for the current node, and when the first flag indicates a second value: the second flag is not included in the bitstream; and the inter prediction is to be used in the prediction process for the current node.
6. A decoding device comprising: a processor; and memory, wherein using the memory, the processor: in a first prediction process performed when a depth of a current node that stores a three-dimensional point is less than a first threshold value, prioritizes inter prediction over intra prediction; in a second prediction process performed when the depth is less than a second threshold value and less than or equal to the first threshold value, uses a prediction scheme indicated in control information included in a bitstream, the second threshold value being greater than the first threshold value; and in a third prediction process performed when the depth is less than or equal to the second threshold value, uses the intra prediction.
7. An encoding device comprising: a processor; and memory, wherein using the memory, the processor: in a first prediction process performed when a depth of a current node that stores a three-dimensional point is less than a first threshold value, prioritizes inter prediction over intra prediction; in a second prediction process performed when the depth is less than a second threshold value and less than or equal to the first threshold value, stores, in a bitstream, control information indicating a prediction scheme used, the second threshold value being greater than the first threshold value; and in a third prediction process performed when the depth is less than or equal to the second threshold value, uses the intra prediction.

Description

[Technical Field] The present disclosure relates to a decoding method, an encoding method, a decoding device, and an encoding device. [Background Art] Devices or services utilizing three-dimensional data are expected to find their widespread use in a wide range of fields, such as computer vision that enables autonomous operations of cars or robots, map information, monitoring, infrastructure inspection, and video distribution. Three-dimensional data is obtained through various means including a distance sensor such as a rangefinder, as well as a stereo camera and a combination of a plurality of monocular cameras. Methods of representing three-dimensional data include a method known as a point cloud scheme that represents the shape of a three-dimensional structure by a point cloud in a three-dimensional space. In the point cloud scheme, the positions and colors of a point cloud are stored. While point cloud is expected to be a mainstream method of representing three-dimensional data, a massive amount of data of a point cloud necessitates compression of the amount of three-dimensional data by encoding for accumulation and transmission, as in the case of a two-dimensional moving picture (examples include Moving Picture Experts Group-4 Advanced Video Coding (MPEG-4 AVC) and High Efficiency Video Coding (HEVC) standardized by MPEG). Meanwhile, point cloud compression is partially supported by, for example, an open-source library (Point Cloud Library) for point cloud-related processing. Furthermore, a technique for searching for and displaying a facility located in the surroundings of the vehicle by using three-dimensional map data is known (see, for example, Patent Literature (PTL) 1). [Citation List] [Patent Literature] [PTL 1] International Publication WO 2014/020663 [Summary of Invention] [Technical Problem] In such encoding methods and decoding methods, there is a demand for improving encoding efficiency. The present disclosure has as an object to provide a decoding method, an encoding method, a decoding device, or an encoding device capable of improving encoding efficiency. [Solution to Problem] A decoding method according to an aspect of the present disclosure includes: in a first prediction process performed when a depth of a current node that stores a three-dimensional point is less than a first threshold value, prioritizing inter prediction over intra prediction; in a second prediction performed when the depth is less than a second threshold value and less than or equal to the first threshold value, using a prediction scheme indicated in control information included in a bitstream, the second threshold value being greater than the first threshold value; and in a third prediction process performed when the depth is less than or equal to the second threshold value, using the intra prediction. A decoding device according to an aspect of the present disclosure includes: a processor; and memory. Using the memory, the processor: in a first prediction process performed when a depth of a current node that stores a three-dimensional point is less than a first threshold value, prioritizes inter prediction over intra prediction; in a second prediction process performed when the depth is less than a second threshold value and less than or equal to the first threshold value, uses a prediction scheme indicated in control information included in a bitstream, the second threshold value being greater than the first threshold value; and in a third prediction process performed when the depth is less than or equal to the second threshold value, uses the intra prediction. [Advantageous Effects of Invention] The present disclosure can provide a decoding method, an encoding method, a decoding device, or an encoding device capable of improving encoding efficiency. [Brief Description of Drawings] [FIG. 1] FIG. 1 is a diagram illustrating an example of a RAHT current node according to an embodiment.[FIG. 2] FIG. 2 is a diagram illustrating a three-dimensional region in an octree structure corresponding to the RAHT current node according to the embodiment.[FIG. 3] FIG. 3 is a flowchart of a first example of encoding processing according to an embodiment.[FIG. 4] FIG. 4 is a flowchart of intra prediction processing by an encoding device according to an embodiment.[FIG. 5] FIG. 5 is a flowchart of determination processing of conditions for performing intra prediction according to an embodiment.[FIG. 6] FIG. 6 is a diagram illustrating the relationship between layers and prediction to be applied in the first example according to the embodiment.[FIG. 7] FIG. 7 is a flowchart of a first example of decoding processing according to an embodiment.[FIG. 8] FIG. 8 is a flowchart of intra prediction processing by a decoding device according to an embodiment.[FIG. 9] FIG. 9 is a flowchart of a second example of encoding processing according to the embodiment.[FIG. 10] FIG. 10 is a diagram illustrating the relationship between layers and pred