Depth Helper Data for 3D Video Rendering

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Solution Overview

Problem

Existing 3D video systems face challenges in providing depth information efficiently, as they require additional data transmission capacity and often rely on unreliable local depth map generation, leading to visually disturbing errors.

Innovation Solution

A system that includes a source device with a stereo-to-depth convertor to generate depth helper data only when differences between the source and locally generated depth maps exceed a threshold, which is then included in the 3D video signal to enhance depth rendering at the destination device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If depth maps are added to the 3D video data stream, then depth information quality is improved, but data transmission capacity requirement increases

Engineering Contradiction:
Improvedepth information qualityVSAvoiddata transmission capacity
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies local quality by selectively providing depth helper data only in specific regions where depth map quality is insufficient. The destination device generates a locally produced depth map and compares it with the source depth map, then receives depth helper data only for regions where the difference exceeds a threshold. This ensures high depth information quality where needed while minimizing additional data transmission.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements partial action by transmitting depth helper data only partially - specifically for regions where quality improvement is necessary rather than providing complete depth maps for the entire video stream. The source device provides depth helper data selectively based on quality requirements, and the destination device uses this partial data to enhance only the necessary portions of the depth map.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If depth helper data is transmitted for all regions, then depth rendering quality is improved, but data transmission amount increases

Engineering Contradiction:
Improvedepth rendering qualityVSAvoiddata transmission amount
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies local quality by selectively providing depth helper data only in specific regions where depth map quality is insufficient. The destination device generates a locally produced depth map and compares it with the source depth map, then receives depth helper data only for regions where the difference exceeds a threshold. This ensures high depth information quality where needed while minimizing additional data transmission.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses copying by having the destination device generate a local copy of the depth map from the stereo video data, then comparing this copied depth map with the source depth map to identify regions requiring enhancement. This allows the system to determine precisely where depth helper data is needed without transmitting helper data for entire regions.

Inventive Principle:
Principle #26Copying

3Quantity of substance

If no depth map data is provided, then data transmission capacity is reduced, but depth map generation errors occur

Engineering Contradiction:
Improvedata transmission capacityVSAvoiddepth map generation reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies preliminary action by having the source device prepare depth helper data in advance for regions where quality issues are anticipated. The source depth map is generated and compared with the expected local depth map at the destination, and depth helper data is prepared beforehand for transmission only where needed, ensuring reliability without excessive data transmission.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary solution by transmitting depth helper data as a intermediate element between the source depth map and the locally generated depth map. This intermediary data allows the destination device to correct errors in its locally generated depth map without requiring complete depth map transmission, thus improving reliability while maintaining data efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2834982B1Depth helper data
Publication Date: 2017.08.09 KONINKLIJKE PHILIPS NV
  • EP2834982B1 patent drawingFigure 1
  • EP2834982B1 patent drawingFigure 2~3
  • EP2834982B1 patent drawingFigure 4~5

AI summary

A hybrid transmission/auto-conversion 3D format and scheme for transmission of 3D data towards various types of 3D displays is described. In the decoder (20) a stereo-to-depth convertor (24) generates a depth map. In the 3D video signal additional depth information called depth helper data (DH-bitstr) is sparsely transmitted both in time (partial depths in time) and/or spatially (partial depth within the frames). A depth switcher (25) selects the partial depths based on an explicit or implicit mechanism for indicating when these are to be used or when the depths must be automatically generated locally. Advantageously disturbing depth errors due to said stereo-to-depth convertor are reduced by the depth helper data.