LED Display Imaging With Single-Camera Moiré Detection

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Solution Overview

Problem

Existing methods for detecting and removing moirés in virtual productions, where a background image is displayed on an LED display and imaged with a real object, are inefficient as they require separate cameras and post-production processing, which can lead to unnoticed moirés and subsequent reimaging.

Innovation Solution

A processing apparatus and method that integrates moiré detection during imaging by using phase-difference detection and correlation calculations on image signals from a single camera, allowing real-time identification and removal of moirés by converting image data into frequency and spatial axis signals to eliminate the frequency components causing moirés.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate camera is used for moiré detection, then moiré detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvemoiré detection capabilityVSAvoidcamera system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines moiré detection functionality with the main imaging camera by processing image signals from the same camera at different imaging angles. Instead of using a separate detection camera, the system utilizes the imaging camera's output signals and applies signal processing techniques (Fourier transform, correlation calculation) to detect moiré patterns, thereby eliminating the need for additional hardware while maintaining detection capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The imaging camera is made multi-functional by enabling it to perform both normal imaging and moiré detection using the same hardware. The system processes the imaging signals to extract moiré information through frequency analysis and correlation calculations, allowing one device to serve multiple purposes without requiring specialized separate equipment

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

2Manufacturing precision

If post-production processing is used for moiré removal, then image quality is improved, but loss of time occurs

Engineering Contradiction:
Improveimage qualityVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs moiré detection and removal during the imaging process itself rather than in post-production. By detecting moiré patterns in real-time using signal processing on the captured images and removing them before final output, the system eliminates the need for time-consuming post-production re-imaging while maintaining image quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements real-time feedback by detecting moiré patterns during imaging and immediately applying correction measures. The correlation calculation results provide feedback on moiré presence, allowing the system to adjust processing parameters or notify operators instantly, preventing the propagation of moiré artifacts and eliminating delays associated with post-production discovery

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables real-time detection and removal of moirés during imaging, preventing post-production issues and improving the quality of captured images by integrating moiré detection within the imaging process.

Implementation Method 1

an image pickup apparatus that includes an imaging unit that captures an image including the display area displaying the first image and generates an image signal

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP4580174A1Processing apparatus, imaging system, processing method, and program
Publication Date: 2025.07.02 CANON KK
  • EP4580174A1 patent drawingFigure 1
  • EP4580174A1 patent drawingFigure 2A~2B
  • EP4580174A1 patent drawingFigure 3

AI summary

A processing apparatus (700) is configured to cause a display apparatus (300) to display a first image, and to acquire from an image pickup apparatus (100) a second image made by capturing at an angle of view including a display area of the display apparatus The processing apparatus includes an acquiring unit (702) configured to acquire a distinction result of distinguishing between an area in which an object existing between the display area and the image pickup apparatus has been captured, and the display area in the second image, a detector (702) configured to detect a change in the second image by comparing the first image with an image of the display area in the second image, and a control unit (702) configured to perform first control for notifying information regarding a detection result.