3D Point Cloud to 2D Image Global Grid Bandwidth Control
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Solution Overview
Problem
Existing 3D content transmission methods using Video-based Point Cloud Compression (V-PCC) face challenges in maintaining constant bandwidth due to varying sizes of 2D images created from 3D point clouds, leading to increased burdens on transmitters and receivers during decoder initialization.
Innovation Solution
An apparatus and method that utilize a global grid generator to determine the size of a 2D image converted from a point cloud, creating a V3C bitstream and extracting grid information for encapsulation into ISOBMFF data, which is then transmitted efficiently using DASH or MMT, ensuring consistent bandwidth and decoder initialization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If V-PCC converts 3D content to 2D image for compression, then existing 2D content transmission methods can be used, but the 2D image size varies making it difficult to guarantee constant bandwidth
Solution Approach 1:
The patent applies preliminary action by pre-defining a maximum image size during the compression process. The encoder determines the maximum dimensions of 2D images that will be generated from the 3D point cloud data, and this maximum size information is embedded in the bitstream. This allows the receiver to allocate buffer memory in advance and ensures that the transmitted data will fit within predetermined bandwidth constraints, preventing variable bandwidth requirements.
Solution Approach 2:
The patent changes the parameter of image size from variable to fixed by establishing a maximum size constraint. Instead of allowing each 2D image to have its own unique dimensions based on the 3D content, the system enforces a uniform maximum size parameter across all images in the sequence. This parameter change enables constant bandwidth transmission while still preserving the adaptive nature of V-PCC compression through the use of maximum size specifications rather than exact size matching.
2Manufacturing precision
If variable sized 2D images are transmitted, then 3D content can be accurately represented, but iterative decoder initialization occurs increasing transmitter and receiver burden
Solution Approach 1:
The patent applies preliminary action by providing maximum size information to the decoder before actual decoding begins. The encoder embeds this maximum dimension data in the bitstream, allowing the receiver to pre-allocate buffer memory and initialize the decoder with the correct expected dimensions. This eliminates the need for iterative initialization attempts, as the decoder is prepared in advance with the appropriate size parameters, reducing both transmitter and receiver complexity.
3Productivity
If constant bandwidth is enforced, then transmission efficiency improves, but decoder initialization information must be precisely managed
Solution Approach 1:
The patent uses an intermediary approach by introducing maximum size information as a mediating parameter between the encoder and decoder. This intermediary data element serves as a contract that defines the expected dimensions of compressed images, allowing both ends to synchronize their operations without losing critical size information. The maximum size acts as a bridge that enables constant bandwidth transmission while preserving all necessary dimensional information needed for proper decoder initialization and operation.
Data Source
AI summary
An apparatus for transmitting 3D contents includes an input configured to receive a point cloud to be converted into a 2D image; a global grid generator configured to create a global grid that determines a size of a 2D image to be converted from the point cloud; a point cloud converter configured to create a V3C bitstream in which the point cloud is converted to a 2D image of a size determined by the global grid based on V-PCC; and a grid information extractor configured to extract size information of the global grid from the V3C bitstream; an encapsulator configured to create ISOBMFF data based on the V3C bitstream and the extracted global grid size information; and a transmitter configured to transmit the ISOBMFF data.