A Versatile Crack Inspection Portable System based on Classifier Ensemble and Controlled Illumination

TL;DR

This paper introduces a portable crack inspection system that uses controlled, multi-height illumination and classifier ensembles to improve crack detection in ceramic tiles under real-world conditions.

Contribution

It is the first study to analyze how height-varying illumination affects crack detection using state-of-the-art classifiers in a portable setup.

Findings

Illumination at different heights significantly impacts crack detection accuracy.

Classifier ensemble improves detection performance over individual classifiers.

The setup is effective for real-world industrial crack inspection.

Abstract

This paper presents a novel setup for automatic visual inspection of cracks in ceramic tile as well as studies the effect of various classifiers and height-varying illumination conditions for this task. The intuition behind this setup is that cracks can be better visualized under specific lighting conditions than others. Our setup, which is designed for field work with constraints in its maximum dimensions, can acquire images for crack detection with multiple lighting conditions using the illumination sources placed at multiple heights. Crack detection is then performed by classifying patches extracted from the acquired images in a sliding window fashion. We study the effect of lights placed at various heights by training classifiers both on customized as well as state-of-the-art architectures and evaluate their performance both at patch-level and image-level, demonstrating the effectiveness of our setup. More importantly, ours is the first study that demonstrates how height-varying illumination conditions can affect crack detection with the use of existing state-of-the-art classifiers. We provide an insight about the illumination conditions that can help in improving crack detection in a challenging real-world industrial environment.