Indoor Illumination Simulation for Camera Tracking

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Solution Overview

Problem

Existing methods for visual camera tracking in indoor scenes are sensitive to outdoor illumination changes, particularly from sunlight, which are not adequately addressed by current illumination simulation techniques, leading to instability and inaccuracy.

Innovation Solution

A method for simulating indoor scene illumination using normalized radiosity maps and brightness scale parameters, accounting for outdoor light sources like the sky, ground, and sun, by separating light contributions and simplifying outdoor geometry into a sphere model, allowing real-time adaptation to changing outdoor conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional indoor illumination models are used, then computational simplicity is maintained, but accuracy under outdoor lighting conditions deteriorates

Engineering Contradiction:
Improveillumination simulation accuracyVSAvoidillumination model complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The illumination model is segmented into multiple independent light sources (sky, ground, sun) with separate radiosity maps computed for each. This allows the system to selectively combine only the relevant light sources for current conditions, maintaining accuracy while managing computational complexity through modular organization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Radiosity maps are pre-computed for each light source position and stored for later retrieval. When simulating illumination, the system only needs to retrieve and combine pre-computed maps rather than performing full radiosity calculations, significantly reducing real-time computational load while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If full radiosity calculations are performed for each light source, then illumination accuracy is improved, but computational load increases

Engineering Contradiction:
Improveillumination simulation accuracyVSAvoidcomputational load
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The system pre-computes and stores radiosity maps for each light source position before runtime. During actual illumination simulation, it only retrieves and combines these pre-computed maps, avoiding repeated full radiosity calculations and reducing computational load to linear combination operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates simplified representations (radiosity maps) of complex lighting scenarios and stores them for reuse. These maps capture the essential illumination characteristics without containing the full computational complexity of the original radiosity calculations, enabling efficient retrieval and combination.

Inventive Principle:
Principle #26Copying

3Reliability

If the system adapts to changing outdoor illumination, then tracking stability is improved, but computational frequency requirements increase

Engineering Contradiction:
Improvetracking stabilityVSAvoidcomputational frequency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system updates illumination parameters at specific intervals (e.g., when sun position changes significantly or sky conditions change) rather than continuously. This periodic update strategy maintains tracking stability by adapting to illumination changes while avoiding excessive computational frequency during stable lighting conditions.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The illumination model dynamically adjusts which light sources are active and their relative intensities based on current outdoor conditions (sun position, sky state). This dynamic adaptation allows the system to respond to illumination changes only when necessary, balancing tracking stability with computational efficiency.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4050568B1A method for simulating the illumination of an indoor scene observed by a camera illuminated by outdoor light
Publication Date: 2025.06.25 TOYOTA JIDOSHA KK
  • EP4050568B1 patent drawingFigure 1
  • EP4050568B1 patent drawingFigure 2
  • EP4050568B1 patent drawingFigure 3

AI summary

A method for simulating, at an instant, the illumination of an indoor scene observed by a camera and being illuminated by outdoor light, the method comprising: a first preliminary phase (P1) including: obtaining (S003, S004) a reflectance map of the scene elaborating normalized radiosity maps for the contribution of the sky and the ground, a second phase (P2) carried out within a first given duration from the instant including: obtaining (S007) the position of the sun, obtaining (S008) a normalized radiosity map for the contribution of the sun, a third phase (P3), including: acquiring an image of the scene, determining (S014, S015) brightness scale parameters for the ground, the sky, and the sun. The invention also proposes tracking the camera position.