Projection System Stroboscopic Pattern Tracking

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Solution Overview

Problem

Existing projection mapping technologies face challenges in accurately tracking and aligning images on moving projection surfaces, particularly when the surface is not solid color, leading to position deviations due to limitations in camera shutter speed and the need for prior markings or complex calculations.

Innovation Solution

A projection system that projects a content image and a pattern image satisfying specific conditions onto a non-solid color projection surface, using a camera to calculate deformation values and adjust the images in real-time to match the surface's movement, ensuring accurate alignment and minimizing position deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a pattern image is used for tracking on a non-solid color projection surface, then the texture on the projection surface can be utilized as a tracking indicator, but position deviation occurs when the projection surface moves rapidly due to camera shutter speed limitations

Engineering Contradiction:
Improveability to track on non-solid color surfacesVSAvoidposition accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies periodic action by projecting a stroboscopic pattern image that alternates between different brightness states (first brightness and second brightness) synchronized with the camera's shutter operation. This periodic brightness variation creates distinct tracking markers that can be detected even during rapid surface movement, overcoming the position deviation problem caused by camera shutter speed limitations while maintaining adaptability to non-solid color surfaces.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If prior alignment and markings are required for projection mapping, then accurate tracking can be achieved, but the technology becomes difficult for users to operate

Engineering Contradiction:
Improvealignment accuracyVSAvoiduser accessibility
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent implements self-service by enabling the projection system to automatically perform alignment and tracking without requiring prior markings or manual configuration. The system projects the stroboscopic pattern image, captures it with the camera, and automatically calculates the projection surface position and movement based on the pattern recognition, thereby achieving accurate alignment while maintaining ease of operation for end users.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If complex calculation methods are used to simulate camera images for tracking, then alignment is not required, but the calculation amount becomes too large to enable real-time content image tracking

Engineering Contradiction:
Improveno alignment requiredVSAvoidreal-time tracking capability
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent applies the extraction principle by isolating and utilizing only the essential high-frequency components of the projection surface texture through the stroboscopic pattern image. Instead of performing complex full-image simulations, the system extracts key positional information from the alternating brightness patterns, significantly reducing calculation requirements while maintaining the ability to track on non-solid color surfaces in real-time.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4024385B1Projection system, projection system control device, projection method, and program
Publication Date: 2025.03.26 TOHOKU UNIV
  • EP4024385B1 patent drawingFigure 1~2
  • EP4024385B1 patent drawingFigure 3
  • EP4024385B1 patent drawingFigure 4~5

AI summary

A projection system includes a projector that projects a content image and a pattern image, a camera that photographs a projection surface when the pattern image is projected, a camera deformation value calculation unit that calculates a texture deformation value indicating a change in position, orientation, or shape of the projection surface on the basis of a photographing result, a projector deformation value acquisition unit that acquires a projector deformation value for converting the content image on the basis of the pattern image captured in the photographing result and the texture deformation value, and a transmission image acquisition unit that executes processing of deforming the content image on the basis of the projector deformation value and processing of deforming the pattern image on the basis of the projector deformation value, and the pattern image satisfies a condition that a plurality of types of solid color regions having different brightness values are included.