Laser Autofocus Using Image-Based Reflection Segmentation

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Solution Overview

Problem

Conventional autofocus systems for through-the-lens microscope applications face challenges with multiple reflective surfaces at varying distances, leading to ambiguity and inefficiency in focusing, especially in high content imaging systems using slides or microtiter plates.

Innovation Solution

A laser-based autofocus system that uses an image-based approach to independently detect and differentiate reflections from multiple surfaces, employing high-resolution cameras to measure location, intensity, shape, and size of reflections, allowing for accurate determination of the sample's z-location with a single measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional autofocus systems are used to handle multiple reflective surfaces, then the system can operate with standard components, but the focus accuracy deteriorates due to ambiguity from multiple reflections

Engineering Contradiction:
Improvefocus accuracyVSAvoidambiguity from multiple reflections
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the reflected light signals by detecting their spatial positions and characteristics. The imaging device captures reflections from different surfaces at different locations in the detection plane, allowing the system to distinguish between plate bottom reflections and sample surface reflections based on their spatial segmentation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds spatial dimensionality to the detection process by using an imaging device that captures two-dimensional spatial information of reflections. This allows the system to differentiate between multiple reflective surfaces by their positions in the image plane, transforming a one-dimensional intensity measurement problem into a two-dimensional spatial analysis problem.

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

2Measurement precision

If repeated re-focusing is performed to determine plate bottom position, then the system can achieve accurate focus, but the productivity deteriorates due to multiple measurement cycles

Engineering Contradiction:
Improvefocus accuracyVSAvoidfocusing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent performs preliminary detection of the plate bottom position by detecting the first reflection signal in the initial position. This preliminary information is used to calculate the focal offset, which then guides the single re-focusing operation, eliminating the need for multiple repeated re-focusing cycles.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the detected reflection signals from the plate bottom are used to calculate the focal offset, which then feeds back to adjust the focal position. This feedback loop enables accurate focusing in a single operation rather than requiring multiple trial-and-error cycles.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If laser-based autofocus is used to resolve multiple reflections, then the focus accuracy improves, but the device complexity increases due to additional laser components

Engineering Contradiction:
Improvefocus accuracyVSAvoidlaser system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the imaging device multi-functional by enabling it to perform both sample imaging and autofocus detection using the same optical path and detection system. The imaging device captures both the sample information and the reflection signals from the plate bottom, eliminating the need for separate laser autofocus components.

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

Solution Approach 2:

The patent merges the autofocus detection function with the existing imaging system by utilizing the same imaging device to capture both sample images and reflection signals. This consolidation integrates multiple functions into a single system, reducing overall device complexity while maintaining focus accuracy.

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

This solution provides faster, more reliable, and robust autofocusing capabilities, capable of handling multiple reflections and varying plate curvatures, improving focus accuracy and speed in high content imaging systems.

Implementation Method 1

there are typically several surfaces, each of which can produce a separate reflection of the laser beam

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

An image is produced of the reflections by the imaging component

Methodology Applied
Scientific EffectImage formation: Photography

Data Source

PatentEP3213136B1Image-based laser autofocus system
Publication Date: 2020.06.03 CELLOMICS INC
  • EP3213136B1 patent drawingFigure 1~2
  • EP3213136B1 patent drawingFigure 3~4
  • EP3213136B1 patent drawingFigure 5

AI summary

Accurate, reliable, and robust laser-based autofocus solutions are presented for through-the-lens microscope applications using slides or micro-titer plates. The laser-based autofocus solutions solve many of the problems that have arisen due to multiple reflective surfaces at varying distances relative to a sample of interest. The laser-based autofocus solutions provide a unique solution to resolve the ambiguity caused by these multiple reflective surfaces by using an image-based approach.