Coaxial Illumination Flare Correction for Accurate Image Measurement

Solution Overview

Problem

Lens flare caused by reflected coaxial episcopic illumination light through a lens leads to inaccurate image measurement and deteriorated image quality in image capturing and microscopy applications.

Innovation Solution

A method involving image acquisition at varying irradiation intensities without an object, estimation of a correction image through interpolation, and generation of a post-correction image by subtracting the correction image from the object image to eliminate lens flare.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If high intensity coaxial episcopic illumination light is used to improve image brightness and surface detail visibility, then image brightness and surface detail are improved, but lens flare occurs due to light reflection from the lens, deteriorating measurement precision and image quality

Engineering Contradiction:

Improveimage brightnessVSAvoidmeasurement accuracy

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent captures a reference image without an object present under the same illumination conditions before capturing the object image. This preliminary reference image records the lens flare pattern, which is then subtracted from the object image to eliminate the flare effect, thereby maintaining both high illumination intensity and measurement precision.

Inventive Principle:

Principle #10Preliminary action

2Illumination intensity

If high intensity coaxial episcopic illumination light is used to improve image brightness and surface detail visibility, then image brightness and surface detail are improved, but lens flare occurs due to light reflection from the lens, deteriorating image quality

Engineering Contradiction:

Improveimage brightnessVSAvoidlens flare

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful lens flare into a usable reference pattern by capturing it in the reference image without an object. This recorded flare pattern is then subtracted from the object image, effectively using the previously harmful flare information to eliminate the flare and improve image quality.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If coaxial episcopic illumination is used to achieve even light distribution and clear surface features, then surface detail visibility is improved, but lens flare from light reflection reduces measurement precision

Engineering Contradiction:

Improvesurface detail visibilityVSAvoidmeasurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent captures a reference image without an object present under the same illumination conditions before capturing the object image. This preliminary reference image records the lens flare pattern, which is then subtracted from the object image to eliminate the flare effect, thereby maintaining both high illumination intensity and measurement precision.

Inventive Principle:

Principle #10Preliminary 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

Eliminates lens flare, improving image measurement accuracy and enhancing image quality in image capturing and microscopy.

Implementation Method 1

reflected light from the object will also reach the image capturing unit through the lens. If the intensity of the coaxial episcopic illumination light is high, part of the coaxial episcopic illumination light is reflected by the lens, and the reflected light here also reaches the image capturing unit and appears in the captured image as flare

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS12495221B2Lens flare elimination method, image capturing apparatus, and image measuring apparatus

Publication Date: 2025.12.09 MITUTOYO CORP

AI summary

A method for eliminating lens flare that eliminates lens flare is provided. The lens flare elimination method performs: a step for acquiring images by irradiating the coaxial episcopic illumination light with varying irradiation intensities and capturing images at each irradiation intensity while the object is not placed on the mounting table; a step for capturing an image of the object by irradiating the object placed on the mounting table with the coaxial episcopic illumination light at an arbitrary irradiation intensity; a step for estimating an image for correction, which is the image at the irradiation intensity irradiated when the measurement object is captured, based on the images acquired in the image acquiring step; and a step for generating a post-correction image in which the lens flare is eliminated from the image of the object by obtaining the difference between the image of the object and the image for correction.