Abstract: A three-dimensional data encoding method includes: (i) in a first case where a layered structure is generated by classifying three-dimensional points into layers: encoding attribute information for the three-dimensional points based on the layered structure; and generating a bitstream including layer information utilized for the generation of the layered structure; and (ii) in a second case where the three-dimensional points are not classified: encoding attribute information for the three-dimensional points; and generating a bitstream not including the layer information.

Abstract: A displacement detection method, performed by a computer, includes: obtaining (i) a first three-dimensional (3D) model representing a region at a first timing by 3D points and including first objects and (ii) a second three-dimensional model representing the region at a second timing by 3D points and including second objects, the second timing being different from the first timing; detecting, by use of attribute information of the first objects and the second objects, (i) first 3D points included in the first 3D model and (ii) second 3D points included in the second 3D model and associated with the respective first 3D points; performing alignment of the first 3D model and the second 3D model by use of the first 3D points and the second 3D points; and detecting displacement between the first 3D model and the second 3D model after the alignment.

Abstract: A three-dimensional data encoding method encodes a plurality of three-dimensional points, and includes: selecting one of two or more prediction modes for calculating a predicted value of an attribute information item of the first three-dimensional point, in accordance with attribute information items of one or more second three-dimensional points in the vicinity of a first three-dimensional point; calculating the predicted value by the selected prediction mode; calculating, as a prediction residual, a difference between a value of the attribute information item of the first three-dimensional point and the calculated predicted value; and generating a bit stream that includes the one prediction mode and the prediction residual.

Abstract: A three-dimensional data encoding method includes: calculating coefficient values from pieces of attribute information of three-dimensional points included in point cloud data; quantizing the coefficient values individually to generate quantized values; and generating a bitstream including the quantized values. Each of the coefficient values belongs to any one of layers. In the quantizing, each of the coefficient values is quantized using a quantization parameter for a layer to which the coefficient value belongs among the layers, and the bitstream includes first information and pieces of second information, the first information indicating a reference quantization parameter, the pieces of second information being for calculating quantization parameters for the layers from the reference quantization parameter.

Abstract: A method for transmitting a bitstream via a network is provided. The bitstream is for coding a current block and is generated by: deriving a first candidate from a first motion vector that has been used to code a first block; coding a first index identifying a reference picture to be used for coding the current block; deriving a second candidate having a second motion vector that includes a non-zero value, which is assigned to the reference picture; and coding a second index identifying a selected candidate to be used for coding the current block. The second motion vector is not derived by coding a block adjacent to the current block, and the non-zero value is assigned by offset values which include an OffsetX and an OffsetY and which are located in a picture header.

Abstract: Various embodiments for transmitting a bitstream via a network are provided. The bitstream includes an index identifying a motion vector from a candidate list. The candidate list is generated by: adding, when a motion vector used for coding a first block spatially adjacent to the current block is useable for coding the current block, one or more first candidates to the candidate list; adding a second candidate to the candidate list, with the second candidate being derived based on a motion vector used for coding a second block within a first collocated picture; and adding a third candidate to the candidate list until a number of the plurality of candidates in the candidate list reaches a maximum number, with the third candidate being derived based on a motion vector used for coding a third block within a second collocated picture.

Abstract: A three-dimensional data encoding method includes: determining, by a first method, a first prediction value of a distance component included in position information of a three-dimensional point; and determining, by a second method, a second prediction value of a direction component included in the position information, the second method being different from the first method. For example, the first method may be inter prediction, and the second method may be intra prediction.

Abstract: A three-dimensional data decoding method includes: performing at least one of: a first process including: determining a first context based on first information identifying a first point cloud including a first prediction point that is referred to for calculating a predicted value of a first three-dimensional point according to inter prediction; and arithmetic-decoding, using the first context determined, second information identifying the first prediction point; or a second process including: determining a second context based on at least one of the first information or the second information; and arithmetic-decoding, using the second context determined, a prediction residual of the first three-dimensional point.

Abstract: A three-dimensional data encoding method includes: obtaining geometry information which includes first three-dimensional positions on a measurement target, and is generated by a measurer that radially emits an electromagnetic wave in different directions and obtains a reflected wave which is the electromagnetic wave that is reflected by the measurement target; generating a two-dimensional image including first pixels corresponding to the directions, based on the geometry information; and encoding the two-dimensional image to generate a bitstream. Each of the first pixels has a pixel value indicating a first three-dimensional position or attribute information of a three-dimensional point which is included in a three-dimensional point cloud and corresponds to a direction to which the first pixel corresponds among the directions.

Abstract: A three-dimensional data encoding method includes: classifying three-dimensional points included in point cloud data into layers, based on geometry information of the three-dimensional points; generating first information indicating whether to permit referring to, for a current three-dimensional point included in the three-dimensional points, attribute information of another three-dimensional point belonging to a same layer as the current three-dimensional point; and encoding attribute information of the current three-dimensional point to generate a bitstream, by or without referring to the attribute information of the other three-dimensional point according to the first information. The bitstream includes the first information.

Abstract: A three-dimensional data decoding method includes: selecting, from among contexts, a first context for an encoded first information item to be processed; and arithmetic-decoding the encoded first information item to be processed, using the first context, to generate a first information item to be processed. Encoded first information items including the encoded first information item to be processed are included in a bitstream generated by encoding an information item about positions of three-dimensional points. The encoded first information items are generated by arithmetic-encoding first information items including the first information item to be processed. The first information items each correspond to a different one of reference positions and indicate whether a three-dimensional point corresponding to a reference position corresponding to the first information item is present.

Abstract: An encoding method for encoding three-dimensional points each having a position represented by a distance and an angle, the encoding method comprising: identifying three-dimensional points that belong to a second processing unit and have been encoded, for inter prediction of a first three-dimensional point belonging to a first processing unit; and selecting a reference three-dimensional point from the three-dimensional points identified to calculate an inter predicted value of the first three-dimensional point. The three-dimensional points identified include a second three-dimensional point and a third three-dimensional point, the second three-dimensional point having a second angle corresponding to a first angle of the first three-dimensional point, the third three-dimensional point having a third angle greater than the second angle.

Abstract: A moving picture decoding apparatus for decoding a current block of a picture is provided. A motion vector candidate list includes motion vector candidates. Each motion vector candidate includes a value. A second candidate is arranged before a first candidate in the motion vector candidate list. The first candidate is sorted before the second candidate in the motion vector candidate list based on the value of the first candidate and the value of the second candidate. An index identifying a motion vector candidate from the motion vector candidate list is decoded, and the current block is generated using the identified motion vector candidate. The value of the first candidate is higher than the value of the second candidate, and the value is based on a number of times the candidate is selected as a motion vector predictor for neighboring blocks.

Abstract: A three-dimensional data encoding method includes encoding information of a current node included in an N-ary tree structure of three-dimensional points included in three-dimensional data, where N is an integer greater than or equal to 2. In the encoding, reference to information of a first node included in neighboring nodes spatially neighboring the current node is permitted, and reference to information of a second node included in the neighboring nodes is prohibited, the first node having a same parent node as the current node, the second node having a different parent node from the parent node of the current node.

Abstract: A three-dimensional data creation method for use in a vehicle including a sensor and a data receiver that transmits and receives three-dimensional data to and from an external device. The three-dimensional data creation method includes: creating second three-dimensional data based on information detected by the sensor and first three-dimensional data received by the data receiver; and transmitting, to the external device, third three-dimensional data that is part of the second three-dimensional data.

Abstract: An image coding method includes: deriving a candidate for a motion vector of a current block from a co-located motion vector; adding the candidate to a list; selecting the motion vector of the current block from the list; and coding the current block, wherein the deriving includes: deriving the candidate by a first derivation scheme in the case of determining that each of a current reference picture and a co-located reference picture is a long-term reference picture; and deriving the candidate by a second derivation scheme in the case of determining that each of the current reference picture and the co-located reference picture is a short-term reference picture.

Abstract: An image coding method includes: writing, into a sequence parameter set, buffer description defining information for defining a plurality of buffer descriptions; writing, into the sequence parameter set, reference list description defining information for defining a plurality of reference list descriptions corresponding to the buffer descriptions; and writing, into a first header of each processing unit which is included in a coded bitstream, buffer description selecting information for specifying a selected buffer description.

Abstract: A displacement detection method, performed by a computer, includes: obtaining (i) a first three-dimensional (3D) model representing a region at a first timing by 3D points and including first objects and (ii) a second three-dimensional model representing the region at a second timing by 3D points and including second objects, the second timing being different from the first timing; detecting, by use of attribute information of the first objects and the second objects, (i) first 3D points included in the first 3D model and (ii) second 3D points included in the second 3D model and associated with the respective first 3D points; performing alignment of the first 3D model and the second 3D model by use of the first 3D points and the second 3D points; and detecting displacement between the first 3D model and the second 3D model after the alignment.

Abstract: A three-dimensional data encoding method uses a first encoding scheme and a second encoding scheme different from the first encoding scheme, and includes: (i) transforming a first quantization parameter to a first scale value or (ii) transforming the first scale value to the first quantization parameter, based on a first table indicating a correspondence between values of the first quantization parameter and values of the first scale value and being shared between the first encoding scheme and the second encoding scheme; performing encoding including a first quantization process to generate encoded attribute information, the first quantization process being a process of dividing, by the first scale value, each of first coefficient values based on items of attribute information of three-dimensional points included in point cloud data; and generating a bitstream including the encoded attribute information and the first quantization parameter.

Abstract: A moving picture coding includes: coding a first flag indicating whether or not temporal motion vector prediction is used; when the first flag indicates that the temporal motion vector prediction is used: coding a first parameter for calculating the temporal predictive motion vector; wherein when the first flag indicates that the temporal motion vector prediction is not used, the first parameter is not coded.