TY - GEN
T1 - Development of an auto-focus system by the moiré method
AU - Lee, Ju Yi
AU - Lin, Yu Ju
AU - Wang, Yung Hsing
AU - Liu, Chien Sheng
PY - 2010
Y1 - 2010
N2 - An auto-focus system based on the moiré effect and the P control method is presented. First, a collimated laser beam passes through a focusing lens and falls incident on the surface of the sample. The deviation of the angle of the light reflected back is proportional to the defocus distance from the sample. The reflected light then passes through two spiral gratings, where three types of moiré patterns are observed and received by a linear CCD. A new formula is derived for finding the focus value (FV) in order to calculate the spiral angle of the moiré pattern and to determine the defocus distance from the sample. The results show that auto-focus should be achieved in a very short time by means of the defocus distance calculation and P control method.
AB - An auto-focus system based on the moiré effect and the P control method is presented. First, a collimated laser beam passes through a focusing lens and falls incident on the surface of the sample. The deviation of the angle of the light reflected back is proportional to the defocus distance from the sample. The reflected light then passes through two spiral gratings, where three types of moiré patterns are observed and received by a linear CCD. A new formula is derived for finding the focus value (FV) in order to calculate the spiral angle of the moiré pattern and to determine the defocus distance from the sample. The results show that auto-focus should be achieved in a very short time by means of the defocus distance calculation and P control method.
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M3 - Conference contribution
AN - SCOPUS:84871590885
SN - 9781617820199
T3 - 10th International Symposium on Measurement and Quality Control 2010, ISMQC 2010
SP - 485
EP - 488
BT - 10th International Symposium on Measurement and Quality Control 2010, ISMQC 2010
T2 - 10th International Symposium on Measurement and Quality Control 2010, ISMQC 2010
Y2 - 5 September 2010 through 9 September 2010
ER -