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URN etd-0728105-144351 Statistics This thesis had been viewed 2665 times. Download 1293 times. Author Yeh-Ju Teng Author's Email Address No Public. Department Communication Engineering Year 2004 Semester 2 Degree Master Type of Document Master's Thesis Language English Page Count 67 Title DEFECT DETECTION FOR FLEXIBLE PCB BY USING DIAGONALWISE WAVELET TRANSFORM Keyword WAVELET FPCB FPCB WAVELET Abstract Generally, the FPCB board is constructed from three structural textures: vertical, horizontal or oblique in degrees of 45 or 135 diagonal. In the original method, the inspection is mainly divided into two parts. The first part makes DWT transform in accordance with the original image, and reconstructions of the defect parts existing in sub-band area to get an inversed image with defect parts. This part mainly aims at defects inspection of the horizontal and vertical circuit lines. The other part will first turn the original image clockwise for 45 degrees to make the oblique circuit lines on the FPCB either 0 or 90 degrees, and then makes the transform of DWT and reconstructions of the sub-band area with defects parts inspected. After the inverse, turn the obtained image 45 degrees counterclockwise to the degrees of the original image. This part is to make inspections on the oblique circuit lines.
Through those steps above, overlapping these two images, we can locate the defect parts of the whole image. But the turning of the second part demanded operation and time many times more than the general one without turning. Moreover, if this is to be achieved in hardware, faults of automatic inspection could be made due to the transformation failures result from the insufficient memories.
This thesis aims mainly at the defects inspection of the oblique circuit lines on FPCB to lower the operation cost and procession time, and raise the efficiency accuracy and realization possibility of the hardware to reach the goal of automatic defects inspection.
Advisor Committee Chao-yun Hsu - advisor
Jung-chin Lo - co-chair
Ming-kuo Ho - co-chair
Files Date of Defense 2005-07-14 Date of Submission 2005-07-28