| CPC G06T 9/001 (2013.01) [G06T 9/40 (2013.01)] | 10 Claims |

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1. A three-dimensional data encoding method comprising:
calculating a coefficient value of each of nodes included in a layered structure by generating the layered structure in which each of items of attribute information of three-dimensional points included in point cloud data is hierarchically divided into a first component and a second component; and
quantizing, for each of the nodes, the coefficient value of the node using one or more first parameters for one or more groups to which one or more items of attribute information used in the calculating of the coefficient value belong, to generate quantized values, wherein
at least one item of attribute information among the items of attribute belongs to any one of the one or more groups,
in the calculating, a second coefficient value of a second node of a second layer which is one layer higher than a first layer of the layered structure is calculated using two first coefficient values of two first nodes belonging to the first layer,
the quantizing includes:
(i) generating one or more second parameters by left-shifting the one or more first parameters by N bits, N being a natural number;
(ii) generating a third parameter by right-shifting, by one bit, a sum obtained by adding up two second parameters from among the one or more second parameters, the two second parameters corresponding to the two first nodes;
(iii) generating a fourth parameter by right-shifting the third parameter by N bits; and
(iv) quantizing the second coefficient value using the fourth parameter, and
each parameter of the one or more first parameters, the one or more second parameters, the third parameter, and the fourth parameter is expressed by a bit sequence.
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