Sistema biométrico híbrido para verificação de assinaturas manuscritas / Hybrid biometric handwritten signature verification system

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

15/12/2008

RESUMO

Through this document the development of a new hybrid on/off-line signature verification system is described, where the dynamic reference data is acquired by either a tablet or an instrumented pen and it is used to support the corresponding static signal (image). The signatures are segmented according to the complexity of their constituent strokes based upon a delta-lognormal psychophysical handwritten reproduction scheme. Foci of attention in the image (windows) are generated and from those regions a personalized static envelope is created. Such envelope helps in localizing the extraction of the local features, obtained through circular data statistics applied over directional probability distribution functions which are extracted from the image and from the interpolated skeleton. Other measures representing the spatial distribution of pixels are also used. The class representative envelope prototype is generated with the respective decision thresholds during the learning stage through an inter-class minimization criterion and its boundaries spatially limit the extraction of local features. Global features are also used, complementing the group of characteristics thence extracted. During the verification process an image is presented to the system with its identification key. The corresponding prototype envelope of the original signature is then read from the database and placed over the test image. The features are obtained and the decision about the authenticity of the specimen is made by a threshold classifier. Such project is original in its essence, since it tries to conciliate advantages of both signature verification methodologies (on-line and off-line). Differently from purely on-line systems, which generally present a better performance, but are of limited use, a hybrid system has direct application on the bank industry, where the supervised acquisition of the reference specimen can be asked without difficulties and the verification is done without author s presence. Other new features include the concept behind the creation of an automatically generated static envelope, inspired by a handwritten reproduction model, as well as its personalization by prototypes, in order to reduce the within-class variation.

ASSUNTO(S)

biometria falsificação de assinaturas reconhecimento de padrões assinaturas biometry falsification of signatures pattern recognition signatures

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