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Marco Querini
    • Marco Querini is a research associate at the department of Civil Engineering and Computer Science Engineering, Univer... moreedit
    ABSTRACT 2D color barcodes have been introduced to obtain larger storage capabilities than traditional black and white barcodes. Unfortunately, the data density of color barcodes is substantially limited by the redundancy needed for... more
    ABSTRACT 2D color barcodes have been introduced to obtain larger storage capabilities than traditional black and white barcodes. Unfortunately, the data density of color barcodes is substantially limited by the redundancy needed for correcting errors, which are due not only to geometric but also to chromatic distortions introduced by the printing and scanning process. The higher the expected error rate, the more redundancy is needed for avoiding failures in barcode reading, and thus, the lower the actual data density. Our work addresses this trade-off between reliability and data density in 2D color barcodes and aims at identifying the most effective algorithms, in terms of byte error rate and computational overhead, for decoding 2D color barcodes. In particular, we perform a thorough experimental study to identify the most suitable color classifiers for converting analog barcode cells to digital bit streams.
    Handwritten Signature Verification (HSV) is a natural and trusted method for user identity verification. HSV can be classified into two main categories: offline and online HSV. Offline systems take handwritten signatures from scanned... more
    Handwritten Signature Verification (HSV) is a natural and trusted method for user identity verification. HSV can be classified into two main categories: offline and online HSV. Offline systems take handwritten signatures from scanned documents, while online systems use specific hardware (e.g., pen tablets) to register pen movements during the act of signing. Online HSV systems may embed signatures (including the signature dynamics) into digital documents. Unfortunately, during their lifetime documents may be repeatedly printed and scanned, and digital to paper conversions may result in loosing the signature dynamics. The main contribution of this work is a new HSV system for secure handwritten signing of documents. First, we illustrate how to verify handwritten signatures so that signature dynamics can be processed during verification of every type of document (both paper and digital documents). Secondly, we show how to embed features extracted from handwritten signatures within the...
    This paper proposes a novel use of 2D barcodes to store biometric data, in particular for facial recognition, which represents one of the least invasive biometric techniques. To accomplish this, we deploy 2D color barcodes, which allow... more
    This paper proposes a novel use of 2D barcodes to store biometric data, in particular for facial recognition, which represents one of the least invasive biometric techniques. To accomplish this, we deploy 2D color barcodes, which allow larger storage capabilities than traditional 2D barcodes. To improve the quality of facial recognition, we combine local feature descriptors, such as SURF descriptors, together with shape landmarks identified through statistical models for discriminating faces. The biometric information can be secured through digital signature algorithms, in order to protect biometric data from malicious tampering. The use of color barcodes is crucial in this setting, as traditional barcodes cannot store a suitable number of SURF descriptors for discriminating faces and cannot even afford to store an additional cryptographic payload. We report the results of an experimental evaluation of our system on real-world data sets (i.e., a face database).
    Handwritten Signature Verification (HSV) is a natural and trusted method for user identity verification. HSV can be classified into two main categories: offline and online HSV. Offline systems take handwritten signatures from scanned... more
    Handwritten Signature Verification (HSV) is a natural and trusted method for user identity verification. HSV can be classified into two main categories: offline and online HSV. Offline systems take handwritten signatures from scanned documents, while online systems use specific hardware (e.g., pen tablets) to register pen movements during the act of signing. Online HSV systems may embed signatures (including the signature dynamics) into digital documents. Unfortunately, during their lifetime documents may be repeatedly printed and scanned, and digital to paper conversions may result in loosing
    the signature dynamics. The main contribution of this work is a new HSV system for secure handwritten signing of documents. First, we illustrate how to verify handwritten signatures so that signature dynamics can be processed during verification of every type of document (both paper and digital documents). Secondly, we show how to embed features
    extracted from handwritten signatures within the documents themselves, so that no remote signature database is needed. To accomplish the embedding task, we make use
    of 2D barcodes. The main challenge here is to be able to store the signature dynamics within the limited capacity of barcodes. Thirdly, we propose a method for the verification of signature dynamics which is compatible to a wide range of mobile devices so that no special hardware is needed. The main challenge here is to achieve a high verification performance, despite constrains due to the limited computational resources and pressure
    accuracy of mobile phones. We address the trade-off between discrimination capabilities of the system and the storage size of the signature model. Towards this end, we report the results of an experimental evaluation of our system on different signature datasets.
    Research Interests:
    We introduce a novel use of 2D barcodes for storing facial biometrics. To accomplish this, we design 2D color barcodes with larger storage capabilities than traditional 2D barcodes. Biometric data are secured through digital signature so... more
    We introduce a novel use of 2D barcodes for storing facial biometrics. To accomplish this, we design 2D color barcodes with larger storage capabilities than traditional 2D barcodes. Biometric data are secured through digital signature so as to be protected from malicious tampering. In order to improve the quality of facial recognition, we combine eigenfaces, shape landmarks identified through statistical models and local features such as SURF descriptors. The use of color barcodes is crucial in this setting, as traditional barcodes cannot store all data required for discriminating faces (e.g., a suitable number of SURF descriptors). We report the results of an experimental evaluation of our system on real-world datasets (i.e., a face database). In spite of the reduced storage available on 2D barcodes, we do not observe any degradation in precision and accuracy
    Research Interests:
    2D color barcodes have been introduced to obtain larger storage capabilities than traditional black and white barcodes. Unfortunately, the data density of color barcodes is substantially limited by the redundancy needed for correcting... more
    2D color barcodes have been introduced to obtain
    larger storage capabilities than traditional black and white
    barcodes. Unfortunately, the data density of color barcodes is
    substantially limited by the redundancy needed for correcting
    errors, which are due not only to geometric but also to chromatic distortions introduced by the printing and scanning process. The higher the expected error rate, the more redundancy is needed for avoiding failures in barcode reading, and thus, the lower the actual data density. Our work addresses this trade-off between reliability and data density in 2D color barcodes and aims at identifying the most effective algorithms, in terms of byte error rate and computational overhead, for decoding 2D color barcodes. In particular, we perform a thorough experimental study to identify the most suitable color classifiers for converting analog barcode cells to digital bit streams.
    Research Interests: