Device and Method for Computing Amount of Drift and Charged Particle Beam System
First Claim
1. A drift amount computing device for computing an amount of drift between a first image and a second image, said drift amount computing device comprising:
- a correlation function computing section for calculating a correlation function between the first and second images;
a local maximum position searching section for searching a range of positions of the correlation function for local maximum positions at which the correlation function assumes its local maxima;
a local maximum position determining section for assigning weights to intensities of the local maximum positions searched for by the local maximum position searching section according to the distance from the center of the correlation function, comparing the weighted intensities, and determining one of the local maximum positions which corresponds to the amount of drift; and
a drift amount computing section for computing the amount of drift, based on the local maximum position corresponding to the amount of drift.
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Abstract
A drift amount computing device (100) computes an amount of drift between a first image and a second image, and comprises a correlation function computing section (112) for calculating a correlation function between the first and second images, a local maximum position searching section (114) for searching a range of positions of the correlation function for local maximum positions, a local maximum position determining section (116) for assigning weights to intensities of plural local maximum positions according to the distance from the center of the correlation function, comparing the weighted intensities of the local maximum positions, and determining one of the maximum local positions which corresponds to the amount of drift, and a drift amount computing section (118).
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Citations
13 Claims
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1. A drift amount computing device for computing an amount of drift between a first image and a second image, said drift amount computing device comprising:
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a correlation function computing section for calculating a correlation function between the first and second images; a local maximum position searching section for searching a range of positions of the correlation function for local maximum positions at which the correlation function assumes its local maxima; a local maximum position determining section for assigning weights to intensities of the local maximum positions searched for by the local maximum position searching section according to the distance from the center of the correlation function, comparing the weighted intensities, and determining one of the local maximum positions which corresponds to the amount of drift; and a drift amount computing section for computing the amount of drift, based on the local maximum position corresponding to the amount of drift. - View Dependent Claims (2, 3, 4, 5, 6, 13)
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7. A method of computing an amount of drift between a first image and a second image, comprising the steps of:
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calculating a correlation function between the first and second images; searching a range of positions of the correlation function for local maximum positions at which the correlation function assumes its local maxima; assigning weights to intensities of the local maximum positions searched for by the step of searching a range of positions according to the distance from the center of the correlation function, comparing the weighted intensities of the local maximum positions, and determining one of the local maximum positions which corresponds to the amount of drift; and computing the amount of drift, based on the local maximum position corresponding to the amount of drift. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification