Depth Map Enrichment for Occlusion Precision

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Solution Overview

Problem

The finite resolution of depth maps leads to approximations in determining occlusion and shadowing, resulting in artifacts like bias aliasing and peter-panning, especially when fragments belong to the same surface.

Innovation Solution

Enhancing the depth map content by associating each element with additional information representing the variation of depth within the element, allowing for more precise depth retrieval at any point within the element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a depth map with finite resolution is used to determine occlusion and shadowing, then the processing is simplified and faster, but the precision of depth determination deteriorates, leading to aliasing artifacts

Engineering Contradiction:
Improveprocessing speedVSAvoiddepth determination precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent divides each depth map element into multiple sub-elements or samples, allowing independent depth determination for different regions within the same element. This segmentation enables more precise depth measurement without requiring the entire depth map to be processed at higher resolution, thus maintaining processing speed while improving precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an additional dimension of sampling within each depth map element, transitioning from a single depth value per element to multiple depth values at different positions or with different weights. This dimensional expansion allows precise depth determination while keeping the overall depth map structure intact for efficient processing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If a bias value is introduced to overcome bias aliasing, then the accuracy of occlusion determination improves, but a new artifact known as peter-panning artifact is introduced

Engineering Contradiction:
Improveocclusion determination accuracyVSAvoidpeter-panning artifact
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies different depth sampling strategies to different regions of the depth map based on local characteristics. Instead of using a uniform bias value across the entire depth map, the system adapts the depth determination method to local areas, applying bias correction only where necessary and using direct comparison where possible, thereby avoiding the peter-panning artifact while maintaining accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts depth determination parameters based on local scene characteristics and depth map properties. By changing the determination method from fixed bias addition to adaptive sampling and comparison, the system eliminates the peter-panning artifact while maintaining accurate occlusion detection.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If depth information is sampled at multiple positions within an element, then the precision of depth retrieval improves, but the data storage and processing complexity increases

Engineering Contradiction:
Improvedepth retrieval precisionVSAvoiddata structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent samples depth information at multiple positions within each element, but only to the extent necessary to achieve the desired precision. Instead of uniformly sampling the entire element, the system applies selective sampling based on the specific requirements of the rendering task, storing only the necessary depth information and using it efficiently during processing.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent pre-computes and stores depth information at multiple sampled positions within each element during the depth map generation phase. This preliminary action allows the system to retrieve precise depth values during rendering without performing complex calculations in real-time, reducing processing complexity while maintaining high precision.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2956910B1Method and device for enriching the content of a depth map
Publication Date: 2025.03.05 THOMSON LICENSING SA
  • EP2956910B1 patent drawingFigure 1
  • EP2956910B1 patent drawingFigure 2~3B
  • EP2956910B1 patent drawingFigure 4~5

AI summary

A method for enriching the content associated with a first element (21) of a depth map (10) the depth map (10) being associated with a scene (1) according to a point of view. Thereafter, at least a first information representative of a variation of depth in the first element (21) in the space of the depth map is established.