| Summary: | 碩士 === 淡江大學 === 資訊工程學系 === 85 === The signature, as we know, is the unique mark representing of
a person. It is usually used in security checking and also is an
important evidence which we tell the original from a forgery or
whether it is a legal paper. Under the circumstances of
accomplishing the NII(National Information Infrastructure),
document-floating automation is the main issue of the process in
which signature verification plays a great role. To achieve this
goal, many people have been making their efforts on the research
of signature verification. Since a signature can be forged and
vary caused by the randomization of the signer, how to extract
good features and choose an appropriate classification method
becomes the very part of our study. In this paper, an on-line
Chinese signature verification system composed of a
preprocessing stage and a verification stage is proposed, which
uses a dynamic information, the velocity of pen-tip movement
while the pen is working on a eletromagnetic tablet, as the only
feature for our verification system. Because such a dynamic
information does not contain only the characteristics of the
signature, but also the particular habit of the signer. First,
we break up the trace of the pen-tip movement on the tablet into
several primitives through some stages. Further, the average
velocity during each segment is separated into two directional
components, the X-axis and Y-axis directional components. In the
verification stage, we compare the directional components of a
testing signature with those of its samples in database by
Relaxation Matching and measure Correlation Coefficient as the
similarity between them. According to this measurement and the
threshold in the database which is measured from the samples by
the same signer, we determine whether the signature is real or
forgery.
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