Projector-Space Compensation Filters for Screen Mottling

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Solution Overview

Problem

Visual displays in simulators suffer from brightness variations (mottling) due to non-uniform paint thickness and optical properties, which can distract users when high contrast is achieved, necessitating a method to adjust projected image brightness.

Innovation Solution

A method involving a processor that receives a captured image, applies a spatial frequency filter, determines a projector-space compensation filter to adjust brightness, and outputs it for projection, using a camera and projector to correct brightness inconsistencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If optimized paint coating processes are used to produce better overall display contrast, then display contrast is improved, but mottling becomes visible and distracts users

Engineering Contradiction:
Improvedisplay contrastVSAvoidmottling visibility
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by capturing an image of the screen with a camera, processing it through spatial frequency filtering to identify mottling patterns, and pre-computing a compensation filter before projection. This allows the system to anticipate and correct brightness variations before they affect the user experience during actual operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful effect of visible mottling into a benefit by using the captured screen image to generate a compensation filter. The spatial frequency analysis identifies the mottling patterns, and the inverse filter is designed to counteract these specific patterns, transforming the problem of visible non-uniformity into a solvable signal processing task that improves overall display quality.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If traditional displays with lower contrast are used, then mottling is not distracting to users, but display quality and visual impact are reduced

Engineering Contradiction:
Improvemottling distractionVSAvoiddisplay contrast
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The patent implements feedback by capturing the actual screen output with a camera, analyzing the captured image to detect brightness variations and mottling patterns, and using this information to generate a compensation filter. This closed-loop approach allows the system to adapt to the specific characteristics of the display screen and correct issues in real-time, enabling high contrast displays without the distracting effects of mottling.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If robotic painting arms are used to ensure consistent paint application, then paint uniformity is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvepaint uniformityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical approach of using robotic painting arms with a digital signal processing solution. Instead of relying on complex mechanical systems to achieve paint uniformity, the system captures the screen image, applies spatial frequency filtering to identify non-uniformities, and generates a computational compensation filter. This substitutes mechanical precision requirements with algorithmic correction, simplifying the manufacturing process while achieving the same goal of uniform display appearance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP4625972A1Method of and system for electronic mottling compensation
Publication Date: 2025.10.01 CAE INC
  • EP4625972A1 patent drawingFigure 1
  • EP4625972A1 patent drawingFigure 2
  • EP4625972A1 patent drawingFigure 3

AI summary

A method for generating a digital filter for adjusting a brightness of a screen, the method being executed by a processor, the method comprising: receiving a captured image of a screen on which a reference image is projected by a projector, the captured image being captured by a camera; applying a spatial frequency filter to the captured image, thereby obtaining a spatially filtered image; determining a projector-space compensation filter based on the spatially filtered image, the projector-space compensation filter being configured for adjusting a brightness of the acquired image; and outputting the projector-space compensation filter.