摘要(英) |
Color filter is one of the important components in TFT-LCD. At present, the defect inspection of color filter is always done by artificial inspection. However, the decision of color filter defect strongly depends on subjective judgment of the inspector. Since the difference of the subjective cognition among these inspectors, it is difficult to achieve the uniform inspection quality. Besides, inspectors may affect the inspection result due to languid sense. Therefore, in order to guarantee the output quality of color filter panel, it is necessary to introduce the machine vision technique which can raise inspection efficiency.
Since the color filter panel involves regular grid texture which consist of vertical lines and horizontal lines, its defects will be inspected with difficulty. For this reason, we use Fourier transform to filter these components which stand for spatial line patterns in frequency spectrum. In addition, we match Gaussian low-pass filter to retain the largest number of the flaws response to achieve our objective.
In the past on the selection of low-pass filter, most of the studies through artificial adjustment and comparison to determine better cutoff frequency range of low-pass filter. In this thesis, we inspect the energy distribution in power spectrum and decide cutoff frequency automatically from distribution characteristic. Furthermore, we propose a method to calibrate the image deflection and reduce the wrong interpretation of results. |
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