Real-Time Key Light Direction Detection in AR

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Solution Overview

Problem

Existing augmented reality systems face challenges in seamlessly integrating virtual 3D objects into real environments due to the lack of accurate lighting direction detection, which requires knowledge of light sources and object micro-surface properties, and often rely on assumptions about the scene or specific objects.

Innovation Solution

A method and apparatus that detect the main lighting direction from an input image using data-parallel architectures, analyzing shading and intensity to estimate light sources without relying on object micro-surface orientation or specific object assumptions, through image analysis, sub-sampling, and spherical parameterization to generate virtual lighting in real-time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If real-time light source detection is implemented using traditional methods, then lighting accuracy for virtual objects is improved, but computational time increases and real-time processing becomes unachievable

Engineering Contradiction:
Improvelighting accuracyVSAvoidreal-time processing capability
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent divides the image processing task into multiple independent segments by processing different regions of the image simultaneously. The image is divided into blocks, and each block is processed by separate processing units that operate in parallel, enabling real-time computation while maintaining accurate light source detection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a spatial dimension to the processing architecture by mapping image pixels to a spherical coordinate system. This dimensional transformation allows parallel processing of light direction estimation across different spatial regions, converting a sequential problem into a parallelizable one that achieves real-time performance.

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

2Measurement precision

If detection methods rely on object micro-surface properties or specific object assumptions, then detection accuracy is improved, but adaptability to general scenes deteriorates

Engineering Contradiction:
Improvedetection accuracyVSAvoidscene adaptability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal detection method that works for any scene without requiring specific object recognition or micro-surface property analysis. The system uses general image intensity and gradient information that is applicable to all scenes, making it versatile while maintaining accuracy through the spherical parameterization approach.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent extracts the essential light source detection task from complex object-specific analysis. By removing dependencies on object identification and micro-surface properties, the system isolates the core function of detecting light directions from general image intensity patterns, enabling broad applicability across different scenes.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If data-parallel architecture is used for real-time processing, then processing speed is improved, but system complexity increases

Engineering Contradiction:
Improveprocessing speedVSAvoidsystem architecture complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the processing system into multiple independent processing units that each handle specific image blocks. This segmentation enables parallel execution while keeping individual units simple, managing overall system complexity through modular design while achieving high processing speed.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3394834B1Key lights direction detection
Publication Date: 2022.05.11 THOMSON LICENSING SA
  • EP3394834B1 patent drawingFigure 1
  • EP3394834B1 patent drawingFigure 2
  • EP3394834B1 patent drawingFigure 3

AI summary

A method and apparatus for detecting a main lighting direction from the input image, which corresponds to a key light. The system is operative to run on data- parallel architectures allows for incoming light direction estimation in real-time. More particularly, the method and apparatus detect a key, or principal light direction relative to the position/orientation of an acquisition device. It method involves image analysis to find a maximum intensity value, maximal values filtering, and conversion of the input image position to a direction in space.