2D Planar VCSEL Array for Adaptive 3D Imaging

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Solution Overview

Problem

Current 3-D imaging technologies are complex and costly, limiting their application to only a few areas due to the need for sophisticated optical sources, detectors, and processors, and they often require calibration procedures that restrict their use to specific environments.

Innovation Solution

A 3-D proximity sensing and imaging apparatus using a 2-D planar array of Vertical Cavity Surface Emitting Lasers (VCSELs) with a programmable current driver and processor for generating various illumination patterns and synchronizing detection, allowing for accurate distance measurement and imaging with low divergence and high output power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sophisticated optical sources and detectors are used for 3-D imaging, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces sophisticated, expensive optical sources with inexpensive LED lights. Instead of using complex detectors, it employs simple photodiodes that are already present in mobile device cameras. The system achieves accurate 3-D imaging by processing multiple 2-D images captured under varying illumination conditions, eliminating the need for specialized expensive hardware while maintaining measurement precision.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent makes the camera system universal by using it for both 2-D photography and 3-D imaging. The same camera module with its existing photodiodes and lens is used for both functions. By illuminating the scene with structured light patterns and processing the captured images through computational algorithms, the system achieves multi-functionality without adding specialized 3-D imaging hardware.

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

2Measurement precision

If sophisticated optical sources and detectors are used for 3-D imaging, then measurement precision is improved, but cost increases

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces sophisticated, expensive optical sources with inexpensive LED lights. Instead of using complex detectors, it employs simple photodiodes that are already present in mobile device cameras. The system achieves accurate 3-D imaging by processing multiple 2-D images captured under varying illumination conditions, eliminating the need for specialized expensive hardware while maintaining measurement precision.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If complex calibration procedures are used, then measurement precision is improved, but ease of operation worsens

Engineering Contradiction:
Improveimaging accuracyVSAvoidcalibration complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent implements self-calibration by capturing images of a calibration pattern (such as a chessboard or grid) that is already present in the scene. The system automatically detects the calibration pattern features and computes the camera parameters and distortion coefficients without requiring manual intervention. This eliminates complex manual calibration procedures while maintaining imaging accuracy.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If high intensity light pulses are used for time of flight measurement, then measurement precision is improved, but use of energy increases

Engineering Contradiction:
Improvedistance measurement resolutionVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent uses periodic modulation of LED illumination at high frequencies (e.g., 100 MHz) rather than continuous high-intensity pulses. By modulating the LED intensity periodically and using synchronous detection in the image processing, the system can measure distance with high precision while consuming significantly less energy compared to continuous high-power illumination. The modulated signal allows extraction of distance information from the phase shift or time delay of the reflected light.

Inventive Principle:
Principle #19Periodic action

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

The solution enables accurate 3-D imaging and sensing with reduced complexity and cost, suitable for everyday applications, providing high-resolution images and distance measurements over larger distances with improved signal-to-noise ratio and adaptability to different ambient light conditions.

Implementation Method 1

an optical source comprising a VCSEL array chip, wherein the VCSEL array chip comprises a plurality of VCSELs

Methodology Applied
Scientific EffectLaser emission: Laser

Implementation Method 2

a radiation detection apparatus... generates one or more electrical signal proportional to reflected radiation received form the one or more object

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentEP2827175B12-D planar VCSEL source for 3-D imaging
Publication Date: 2021.05.05 PRINCETON OPTRONICS INC
  • EP2827175B1 patent drawingFigure 1(a)~1(d)
  • EP2827175B1 patent drawingFigure 2(a)~2(d)
  • EP2827175B1 patent drawingFigure 3(a)~3(b)

AI summary

An apparatus (710) and a method are provided for 3-D proximity sensing, imaging and scanning using a 2-D planar VCSEL array source (730) using reflected radiation from an object (720) being detected. An important feature of the apparatus (710) is a compact high power optical source and in particular, an optical source (730) comprising a plurality of VCSELs to illuminate the object (720). VCSELs in the optical source are configured in different 2-D planar arrangements, such that the optical source may be used in many different modes to adapt to different sensing, imaging and scanning requirement suited for different environments including one where shape, size and illumination mode require to be altered dynamically. When used in different modes of operation the apparatus (710) provides a comprehensive set of measured distance and intensity profile of the object (720) to compute a 3-D image.