A Novel Pixel-wise Defect Inspection Method Based on Stable Background Reconstruction

Optical polarizing thin film is an optical filter enables light waves of a specific polarization pass through while blocking light waves of other polarizations. Optical polarizing thin films control the brightness of back-light unit for LCD (liquid crystal display) panel, which is essential to produce LCD modules. Defect inspection of polarizing thin films is an important feature during the manufacturing process that is helpful to improve the product quality. In the current study, an automated defect inspection algorithm is introduced and incorporated with a well-known non-destructive and non-contact optical inspection method called spectral domain optical coherence tomography (SD-OCT) to pre-identify defective sub-surface as well as top-surface locations of optical polarizing thin films Polarizing thin films employed in this study consist of 6 layers. The tomographic information, layer information, and defective locations were sufficiently identified through the SD-OCT system owing high-axial resolution. The acquired results indicate the possible application of the proposed system in optical polarizing thin films for the quality assurance

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A Basic Study on Defect Inspection Method for ASIC Manufacturing Line (Third Report: A Proposal of Inspection Methodology Based on Chip Cost)

IEEJ Transactions on Industry Applications ◽

10.1541/ieejias.124.15 ◽

2004 ◽

Vol 124 (1) ◽

pp. 15-23

Author(s):

Koichi Sakurai ◽

Susumu Fujii ◽

Toshiya Kaihara

Keyword(s):

Defect Inspection ◽

Basic Study ◽

Inspection Method ◽

Manufacturing Line ◽

On Chip

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Weld defect inspection based on machine vision and weak magnetic technology

Insight - Non-Destructive Testing and Condition Monitoring ◽

10.1784/insi.2021.63.9.547 ◽

2021 ◽

Vol 63 (9) ◽

pp. 547-553

Author(s):

Jing Ye ◽

Guisuo Xia ◽

Fang Liu ◽

Ping Fu ◽

Qiangqiang Cheng

Keyword(s):

Machine Vision ◽

Average Height ◽

Defect Inspection ◽

Welding Seam ◽

Inspection Method ◽

Weld Formation ◽

Weld Defect ◽

Inspection Process ◽

Weld Area

This study proposes a weld defect inspection method based on a combination of machine vision and weak magnetic technology to inspect the quality of weld formation comprehensively. In accordance with the principle of laser triangulation, surface information about the weldment is obtained, the weld area is extracted using mutation characteristics of the weld edge and an algorithm for identifying defects with abnormal average height in the weld surface is proposed. Subsequently, a welding seam inspection process is developed and implemented, which is composed of a camera, a structured light sensor, a magnetic sensor and a motion control system. Inspection results from an austenitic stainless steel weldment show that the method combining machine vision and magnetism can identify defect locations accurately. Comprehensive analysis of the test results can effectively classify surface and internal defects, estimate the equivalent sizes of defects and evaluate the quality of weld formation in multiple dimensions.

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