Frequency Domain Defect Inspection Training Data Creation

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Solution Overview

Problem

Existing defect inspection methods for equipment like piping require numerous sample images to ensure accuracy, which is challenging due to low occurrence frequency of certain defects and confidentiality issues, leading to inefficiencies in defect detection.

Innovation Solution

A training data creation method that involves frequency distribution analysis and band-pass filtering to standardize image shades, allowing for accurate defect inspection even with limited sample images, by selecting a frequency bandwidth signal and creating training data based on defect information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If many sample images are collected to ensure inspection accuracy, then defect detection accuracy is improved, but the time and resources required for data collection increase significantly

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidtime for data collection
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing frequency distribution analysis and band-pass filtering on training images before they are used for machine learning training. This preprocessing standardizes the shade characteristics of defect images in advance, allowing the system to achieve high detection accuracy with fewer sample images. The frequency components are analyzed and filtered beforehand to emphasize defect-related features while suppressing irrelevant variations, thus reducing the need for extensive data collection.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If many sample images with various shades are collected to cover defect variations, then inspection accuracy is improved, but the difficulty of obtaining sufficient samples increases due to low defect occurrence frequency

Engineering Contradiction:
Improveinspection accuracyVSAvoiddifficulty of obtaining sample images
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies parameter changes by transforming the training images through frequency domain analysis and band-pass filtering. This changes the parameter representation of the images from spatial domain to frequency domain, allowing the system to extract and emphasize defect-related frequency components. By adjusting the band-pass filter parameters, the system can adapt to different defect types and conditions, effectively handling the variability in defect shades and appearances without requiring numerous physical samples.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If traditional defect inspection methods are used without frequency analysis, then the inspection process is simpler, but the accuracy of defect detection decreases when sample images are limited

Engineering Contradiction:
Improveinspection process complexityVSAvoiddefect detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies segmentation by dividing the image processing into distinct frequency components through Fourier transform and band-pass filtering. Instead of processing the entire image as a single unit, the method segments the frequency spectrum to isolate and emphasize defect-related components. This segmentation allows the machine learning model to focus on specific frequency ranges that are most indicative of defects, improving detection accuracy without requiring excessive complexity in the overall inspection process.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11386542B2Training data creation method and device, and defect inspection method and device
Publication Date: 2022.07.12 FUJIFILM CORP
  • US11386542B2 patent drawing
  • US11386542B2 patent drawing
  • US11386542B2 patent drawing

AI summary

Provided are a training data creation method and device, and a defect inspection method and device capable of securing the accuracy of defect inspection even though the number of samples of a defect to be used in creating training data is small.The training data creation method includes acquiring a training-use image including a received light image created based on reflected light or transmitted light from an inspection object having a defect obtained by irradiating the inspection object with light rays or radiation, executing frequency distribution analysis on the training-use image, receiving an input of a parameter for designating a frequency bandwidth, selecting a frequency bandwidth signal from an analysis result of the frequency distribution analysis according to the frequency bandwidth designated by the parameter, acquiring defect information indicating a defect for an image corresponding to the frequency bandwidth signal, and creating training data to be used in learning of a defect inspection device, which inspects a defect of the inspection object, based on the defect information.