Patent ID: 11936841
Assignee: B1 INSTITUTE OF IMAGE TECHNOLOGY, INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 0:
1. A method of decoding a 360-degree image performed by an image decoding apparatus, the method comprising:
receiving a bitstream in which the 360-degree image is encoded, the bitstream including data of an expanded 2-dimensional image, the expanded 2-dimensional image including a 2-dimensional image and a predetermined expansion region, and the 2-dimensional image being projected from an image with a 3-dimensional projection structure and including one or more faces;
generating a predicted image by performing prediction based on information on the prediction included in the bitstream; and
reconstructing the expanded 2-dimensional image based on the predicted image and a residual image,
wherein a size of the expansion region is determined based on first width information of the expansion region on a left side of the face and second width information of the expansion region on a right side of the face, both the first width information and the second width information being obtained from the bitstream,
wherein sample values of the expansion region are determined differently according to a padding method selected from a plurality of padding methods,
wherein the sample values of the expansion region are determined by horizontally copying the sample values of the face according to the padding method selected from the plurality of padding methods,
wherein the size of the expansion region is determined based on size information obtained from the bitstream,
wherein the predicted image is added to the residual image to reconstruct the expanded 2-dimensional image,
wherein the number of syntax elements for the size information is determined differently based on a projection format for the 3-dimensional projection structure, the projection format being one among a plurality of projection formats including an ERP format in which the 360-degree image is projected in a two-dimensional plane and a CMP format in which the 360-degree image is projected in a cube,
wherein the residual image is obtained by decoding residual information included in the bitstream, and
wherein the 3-dimensional projection structure is selectively determined based on identification information, among a plurality of pre-defined projection formats including the ERP format in which the 360-degree image is projected in the two-dimensional plane and the CMP format in which the 360-degree image is projected in the cube.