Image Alignment for Displacement Tolerance in Industrial Inspection
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Solution Overview
Problem
In industrial inspection systems using fixed cameras, image displacement between objects leads to reduced inspection accuracy when applying existing algorithms that rely on peripheral vision and involuntary eye movement during fixation, as both actual flaws and image displacement can result in false singular portion extraction.
Innovation Solution
An image processing apparatus and method that generates an aligned image by arranging candidate images around a work inspection image, subjects it to similar region extraction processing, and determines a work reference image through averaging of division regions with varying sizes and phases to mitigate the effects of image displacement, allowing for accurate comparison and defect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed camera is used to sequentially inspect objects on a manufacturing line, then the inspection process can be automated and continuous, but image displacement occurs between successive objects leading to reduced inspection accuracy
Solution Approach 1:
The patent divides the image processing into multiple stages: extracting multiple candidate images from the reference image, extracting a work inspection image from the inspection target image, and then comparing these segmented images. This segmentation allows the system to handle displacement by evaluating multiple candidates rather than relying on a single fixed-position reference.
Solution Approach 2:
The patent changes the parameter of image selection by evaluating multiple candidate images with different positions and selecting the one that best matches the work inspection image. This parameter change approach allows the system to adapt to displacement variations while maintaining inspection accuracy.
2Difficulty of detecting and measuring
If existing algorithms based on peripheral vision and involuntary eye movement are applied to displaced images, then defect detection can be performed, but false singular portion extraction occurs due to image displacement
Solution Approach 1:
The patent performs preliminary actions by extracting multiple candidate images from the reference image before comparing with the work inspection image. This preliminary extraction and alignment process eliminates displacement effects before the actual defect detection algorithm is applied, preventing false singular portion extraction.
Solution Approach 2:
The patent introduces an intermediary process of image alignment and candidate selection between the image acquisition and defect detection stages. This intermediary step ensures that the images being compared are properly aligned, preventing displacement from causing false defect detection.
Data Source
AI summary
An image processing apparatus having a generation unit configured to generate an aligned image by arranging a plurality of candidate images extracted from a reference image around a work inspection image extracted from an inspection target image; a unit configured to subject the aligned image to similar region extraction processing to represent a similarity between regions in the aligned image; a determination unit configured to select a candidate image and determine it as a work reference image based on the aligned image after being subjected to the similar region extraction processing; and a comparison unit to compare the work inspection image with the work reference image. The similar region extraction processing subjects each of a plurality of division regions obtained by dividing the aligned image based on predetermined division size and phase, to averaging processing, and then adds the results of the averaging processing that are obtained by varying at least one of the division size and phase.