Scanning Light Field Imaging for High-Resolution 3D Reconstruction

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Solution Overview

Problem

Conventional light field imaging techniques using microlens arrays suffer from low spatial resolution, scattering effects, and require complex wave-optical reconstruction, which can increase computing demands or reduce accuracy, especially when imaging light-sensitive samples like biological cell cultures.

Innovation Solution

An optical device with scanning optics that selectively guides light from different angular ranges onto a detector for multiple scanning positions, using a photomultiplier with fewer pixels and collimating optics to achieve high spatial and depth resolution, allowing for precise generation of 3D images with improved sensitivity and reduced light exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an array of microlenses is used for light field imaging, then depth information can be captured, but the spatial resolution is comparatively low due to fixed scanning intervals

Engineering Contradiction:
Improvespatial resolutionVSAvoidfixed microlens array structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the fixed microlens array with a dynamic scanning system where a single lens or mirror scans through multiple positions to capture light field data. This dynamic approach allows flexible adjustment of scanning intervals and positions, achieving high spatial resolution without the structural constraints of a fixed array.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention extracts the light field measurement function from the fixed microlens array structure and implements it through a scanning mechanism. By removing the array structure and using sequential scanning, the system achieves comparable or superior resolution with reduced structural complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If microlenses with low Fresnel numbers are used, then the device can be manufactured, but additional scattering effects occur particularly for objects far from the object plane

Engineering Contradiction:
Improvemicrolens fabricationVSAvoidscattering effects
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a scanning mechanism as an intermediary between the light source and detector, replacing the problematic microlens array. This intermediary system captures light field information through sequential scanning, avoiding the scattering effects inherent in low Fresnel number microlenses while maintaining manufacturability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If wave-optical reconstruction techniques are used to generate images, then spatially resolved images can be obtained, but the reconstruction becomes comparatively complex requiring more computing resources

Engineering Contradiction:
Improveimage reconstruction accuracyVSAvoidreconstruction algorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The scanning system performs preliminary organization of light field data during the scanning process itself, capturing measurements in a structured sequence that simplifies subsequent reconstruction. This preliminary structuring of data reduces the computational complexity of the reconstruction algorithm compared to processing data from fixed microlens arrays.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If microlenses with long focal lengths are used, then the device can be constructed, but the light field cannot have constant resolution as a function of depth; resolution is particularly low near the image plane

Engineering Contradiction:
Improvemicrolens focal lengthVSAvoiddepth-dependent resolution
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent uses a dynamic scanning approach with a single lens or mirror that can be positioned at multiple locations along the optical path. This allows the system to maintain constant resolution across different depth planes by adjusting the scanning positions, overcoming the depth-dependent resolution limitation of fixed focal length microlenses.

Inventive Principle:
Principle #15Dynamics

5Quantity of substance

If CCD sensors are used for light field imaging, then a large number of pixels are available, but the sensitivity is comparatively low requiring high light intensity which is disadvantageous for light-sensitive samples

Engineering Contradiction:
Improvenumber of detector pixelsVSAvoidlight exposure to samples
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the light collection function from the multi-pixel CCD sensor and concentrates it into a single high-sensitivity detector through the scanning mechanism. By sequentially directing light from different angular ranges to a single high-sensitivity detector, the system achieves equivalent spatial sampling with much lower light exposure to the sample.

Inventive Principle:
Principle #2Taking out (Extraction)

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 high-resolution, noise-free 3D imaging with improved sensitivity and reduced light exposure, overcoming the limitations of conventional microlens array-based light field imaging by achieving high spatial and depth resolution while minimizing measurement duration.

Implementation Method 1

The scanning optic is configured to selectively direct light incident from the object at different angular ranges onto the detector for a plurality of scan positions

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

using a photomultiplier with fewer pixels

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3179288B1Light field imaging with scan lens
Publication Date: 2023.04.26 CARL ZEISS MICROSCOPY GMBH
  • EP3179288B1 patent drawingFigure 1
  • EP3179288B1 patent drawingFigure 2
  • EP3179288B1 patent drawingFigure 3

AI summary

An optical device comprises a light source and a detector (118), as well as a sample holder configured to fix an object (250) in the optical path (161) of light. A scanning optic (114, 115, 116, 122) is configured to selectively direct light incident from the object (250) at different angular ranges onto the detector (118) for a multitude of scan positions. Based on a three-dimensional light field represented by corresponding measurement data from the multitude of scan positions (290), a spatially resolved image of the object (250) is generated, comprising at least two images from different object planes.