2D Detection of Embedded Light Codes Using Periodic Shuttering

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Solution Overview

Problem

Current illumination systems struggle to detect embedded codes in light sources across a two-dimensional scene in real time using conventional low-cost cameras, as they require high acquisition rates to detect high-frequency codes, which are invisible to the human eye, and existing methods either fail to detect multiple codes or require expensive cameras.

Innovation Solution

A detection system that captures a series of images with varying exposure times within a frame time to correlate the presence of embedded codes, allowing for the identification of light sources in a 2D scene using conventional cameras by processing the intensity sums of pixels over multiple images, enabling the detection of invisible high-frequency codes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If high-frequency codes are embedded in light output to make them invisible to the human eye, then code invisibility is improved, but detection capability with conventional low-cost cameras deteriorates because they lack sufficient acquisition rate

Engineering Contradiction:
Improvecode visibility to human eyeVSAvoiddetection capability with conventional cameras
Core Design Contradiction:
Object-affected harmful factorsVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies periodic action by using a light shutter to periodically block and unblock light at specific time intervals within a frame period. This allows the camera to capture light intensity variations at multiple time points, enabling detection of high-frequency coded light patterns that would otherwise be invisible. The periodic shutter operation synchronizes with the coded light frequency to extract information across multiple acquisitions.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent transitions from single-point detection to two-dimensional scene detection by processing pixel data across the entire image sensor array. Multiple pixels simultaneously detect light from different spatial positions, and the system correlates intensity variations across the two-dimensional pixel grid to identify coded light sources and their locations in the scene.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Difficulty of detecting and measuring

If camera acquisition rate is increased to detect high-frequency codes, then detection capability is improved, but device cost increases due to requirement for expensive high-speed cameras

Engineering Contradiction:
Improvedetection capabilityVSAvoidcamera cost
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent uses periodic shutter operation within a single frame period to effectively increase the detection sampling rate without requiring a high-frame-rate camera. By opening and closing the shutter multiple times during one camera frame exposure, the system captures multiple samples of the coded light signal, enabling high-frequency detection with low-cost cameras that have slower frame rates.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent performs preliminary correlation processing on the acquired pixel data to identify coded light patterns before final detection. The system pre-processes the intensity data from multiple time points and spatial positions, correlating it with expected code patterns to extract information, thereby enabling detection with conventional cameras that would otherwise be insufficient for high-frequency codes.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If single-position code detection is used, then device complexity is reduced, but scene characterization capability deteriorates as it cannot detect codes at multiple positions simultaneously

Engineering Contradiction:
Improvedetection system complexityVSAvoid2D scene characterization capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent extends detection from a single spatial position to the entire two-dimensional scene by utilizing the camera's pixel array. Each pixel independently detects light intensity variations, and the system processes the two-dimensional grid of pixel data to identify multiple coded light sources simultaneously across different positions in the scene, achieving full scene characterization.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent combines the detection capability across all pixels in the camera sensor array to simultaneously detect multiple codes in different spatial positions. By merging the information from all pixel detections and correlating their temporal and spatial patterns, the system identifies multiple light sources and their respective codes within a single two-dimensional scene capture.

Inventive Principle:
Principle #5Merging (Combining)

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 of embedded codes from multiple light sources in a 2D scene using less expensive cameras, improving user interaction and scene setting capabilities while maintaining code invisibility to the human eye.

Implementation Method 1

a camera sensor configured to detect light from a scene and generate image data corresponding to the detected light

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2524575B1Method and system for 2d detection of localized light contributions
Publication Date: 2019.05.08 SIGNIFY HOLDING BV
  • EP2524575B1 patent drawingFigure 1
  • EP2524575B1 patent drawingFigure 2
  • EP2524575B1 patent drawingFigure 3

AI summary

The invention relates to a detection system for determining whether a light contribution of a light source is present at a selected position within a 2D scene. The light contribution includes an embedded code comprising a repeating sequence of N symbols. The detection system includes a camera and a processing unit. The camera is configured to acquire a series of images of the scene via specific open/closure patterns of the shutter. Each image includes a plurality of pixels, each pixel representing an intensity of the light output of the light source at a different physical position within the scene. The processing unit is configured to process the acquired series of images to determine whether the light contribution of the first light source is present at the selected physical position within the scene by e.g. correlating a sequence of pixels of the acquired series corresponding to the selected physical position with the first sequence of N symbols.