Projection System Using Infrared Structured Light for 3D Measurement

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Solution Overview

Problem

Existing projection systems face challenges in obtaining accurate three-dimensional measurements and fast two-dimensional detection of objects, particularly in dynamic environments, which hinders precise image projection and mapping.

Innovation Solution

A projection system that combines a visible light projector, an infrared light projector, and a camera, using spatial coding schemes and infrared light illuminators to capture and project images, enabling real-time three-dimensional measurements and high-speed two-dimensional detection by distinguishing between bright and dark regions in the projected patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If structured light projection is used for three-dimensional measurement, then measurement precision is improved, but detection time increases

Engineering Contradiction:
Improvethree-dimensional measurement precisionVSAvoiddetection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The measurement process is divided into two independent stages: first capturing the invisible light image for three-dimensional shape measurement, then capturing the visible light image for two-dimensional feature detection. This segmentation allows both measurements to proceed without interfering with each other, reducing total detection time while maintaining precision for both 3D and 2D measurements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses periodic projection of invisible light patterns followed by periodic capture of visible light images in a time-multiplexed manner. This periodic action enables the structured light measurement and color image capture to be performed in alternating cycles, achieving both 3D precision and 2D speed without requiring simultaneous operation

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If invisible light projection is used for three-dimensional measurement, then measurement accuracy is improved, but information on object color and texture is lost

Engineering Contradiction:
Improvethree-dimensional measurement accuracyVSAvoidobject color and texture information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The system merges the invisible light projection system for 3D measurement with a visible light imaging system for color and texture capture. By combining these two systems and integrating their data in post-processing, the invention recovers both the geometric information from invisible light and the color/texture information from visible light, eliminating the information loss that would occur with invisible light alone

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The visible light camera acts as an intermediary that captures color and texture information during the same measurement cycle as the invisible light projection. This intermediary visible light imaging compensates for the information loss inherent in invisible light measurement, providing a complete description of the object including both geometry and appearance

Inventive Principle:
Principle #24Intermediary (Mediator)

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 precise image projection that follows the motion of objects, reduces detection time, and facilitates accurate three-dimensional measurement and two-dimensional position determination, enhancing the precision and speed of image mapping and projection.

Implementation Method 1

captures an image of the invisible light projected from the invisible light projector

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3524929B1Projection system
Publication Date: 2022.05.11 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3524929B1 patent drawingFigure 1
  • EP3524929B1 patent drawingFigure 2
  • EP3524929B1 patent drawingFigure 3A~3B

AI summary

A projection system (1) for projecting an image (71) comprises: a visible light projector (23) that projects the image with visible light; an invisible light projector (30, 33) that projects an invisible light image onto the object with invisible light; an imaging device (43) that captures the invisible light image projected from the invisible light projector; and a controller (5) that obtains information regarding reflected light from the object while obtaining three-dimensional measurements of the object to control the image, based on a capture image. The invisible light image includes a bright region (Rl) and a dark region (R0) having a light amount less than the light amount of the bright region. The invisible light projector emits the invisible light to cause the light amount of the dark region in the invisible light image to be more than or equal to an offset value (b).