Luis Mengibar-Pozo

On-Line Signature Verification by Dynamic Time Warping and Gaussian Mixture Models

Handwriting signature is the most diffuse mean for personal identification. Lots of works have been carried out to get reasonable errors rates within automatic signature verification on-line. Most of the algorithms that have been used for matching work by features extraction. This paper deals with the analysis of discriminative powers of the features that can be extracted from an on-line signature, how its possible to increase those discriminative powers by dynamic time warping as a step in the preprocessing of the signal coming from the tablet. Also it will be covered the influence of this new step in the performance of the Gaussian mixture models algorithm, which has been shown as a successfully algorithm for on-line automatic signature verification in recent studies. A complete experimental evaluation of the algorithm base on dynamic time warping and Gaussian Mixture Models has been conducted on 2500 genuine signatures samples and 2500 skilled forgery samples from 100 users. Those samples are included at the public access MCyT-Signature-Corpus Database.

Analysis on compact data formats for the performance of handwritten signature biometrics

This paper deals with the Signature Data Formats proposed by ISO 19794 project: 19794 part 7 Full Format and Compact Format (published in 2007) and the new 19794 part 11, which is under development. It will be shown how these formats handle the raw data coming from a Signature Input Device, and what the size of a Biometric Information Record is for each one. Another compression method, using LZ77 compression algorithm, is proposed and tested. The paper will also show the impact of using these compact formats on the performance of two different algorithms: Dynamic Time Warping and Gaussian Mixture Models. MCyT and SVC2004 signature databases have been used to carry out all tests.

A new algorithm for signature verification system based on DTW and GMM

This paper continue our previous work on combining dynamic time warping and Gaussian mixture modelling for automatic signature verification. MCyT signature database which contains data for 100 users, with 25 genuine and 25 forged signatures per users, has been used to test the proposed methods.

Microprocessor smart cards with fingerprint user authentication

Due to the great increase in information technology systems where user authentication is needed, security relies on using PINs or passwords. The scientific community is trying to improve biometric techniques in order for them to be accepted as an alternative to other user authentication schemes. One sector where user identity must be verified is identification cards. In fact, if high level security is to be achieved, smart cards should be used, but cardholder verification is performed using CHV-keys, which are PIN-based. The authors are trying to integrate fingerprint verification inside a smart card. A fingerprint scheme is shown, and work to achieve integration inside a commercial smart card is discussed.

Optimisation of biometric ID tokens by using hardware/software co-design

In current society, the necessity of recognising people is increasing every day. Logical or physical access is restricted to authorised users, which in many cases have to provide tokens where their personal information is stored. At the same time, biometrics proposes a feasible solution for the recognition problem. The combination of both solutions is coming up front. However, up till now, owing to processing restrictions, these tokens are just able to store data and perform the last steps of the biometric recognition process. In this study, the authors propose a new system where tokens are based on hardware/software (HW/SW) co-design, which allows computing most of the biometric process in them. This proposal covers several aspects which these systems are subject to, taking advantages of the two platforms they use for reducing computational time or HW area, and also to increase security or minimise misidentification errors. For testing this proposal, an Iris ID token has been implemented, showing different design alternatives adapted to different work scenarios.

User-friendly biometric camera for speeding iris recognition systems

Among biometric modalities existing nowadays for person identification, iris pattern recognition has reputed as one of the best performance systems. Unfortunately it has the lack of the user-friendliness that can be seen in hand geometry or face systems. To overcome these problems we propose a new kind of camera to capture iris image.

Low-power design in aerospace circuits: A case study

The results of applying low-power design techniques to a circuit used in a space application have been presented. The design used for the experiments was implemented in an antifuse FPGA (ACTEL RT14100A). Power consumption was first estimated by simulation of the design to identify the elements that had a higher impact on the total power consumption. According to the power estimations, the more suitable power reduction techniques were identified and applied to reduce power consumption of the initial design. With this approach, the worst-case power consumption was reduced to 30% of the original power estimations by using gated clocks and redesigning small critical components with an asynchronous style. Further reduction, typically up to 16% of the original value, was possible by applying architectural modifications. These results show that important power savings are possible for FPGA designs by following the appropriate methodology. Precise estimation of the contribution of the various functional units to the total power is essential to target only those modifications that are significant from the power point of view and to avoid large redesign efforts.

Compressed data format for handwritten signature biometrics

In this work, the authors explore different lossless strategies of organizing the sample point values from an on-line signature data format, in order to obtain higher compression performance. A new near-lossless strategy of organizing sample point values is also proposed, with the introduction of a control error difference level mechanism. Seven different data compression algorithms and three public databases have been tested in order to find the compression ratios for these new strategies, identify if a better data compression algorithm exists and the influence from the origin of the database, i.e. different populations signing in very different ways. The authors have also carried out an algorithm evaluation to investigate the impact of the information lost on several data formats on the Signature Verification performances.

Image compact formats of iris samples for interoperability in biometric systems

In order to lower data storage requirements for ID tokens or databases, compact formats are needed in any biometric modality. As there is no morphological parameters that could help in reducing data, as it happens with minutiae in fingerprints, iris needs a data reduction at the raw image level. This is becoming quite a controversial issue among this technology community. Two major approaches are suggested. The first one is using cropped sub-images of the sample acquired. The second one is using a polar representation of the iris. This paper reflects one of the parallel works that is been carried out in order to achieve such a compact format. Authors have studied several representations from both approaches. They have analyzed data size requirements and processing time, while some important remarks about interoperability are given.

Common Interface for Connecting of Low Profile Biometric Modules

For improving interoperability and gaining in many more benefits, standard interfaces for connecting modules in Information Technology (IT) are a need. Biometrics is not different from other IT fields. In fact in Biometrics those interfaces are needed at different levels: applications, data interchange, processing modules or sensors. Standardization bodies have already published standards related to data interchange and application programming interfaces (API), but some others are still missing. Authors present in this paper a first approach for a definition of a common interface for those biometric related modules to be integrated in small and low cost embedded systems. Definition is done at two different levels, leaving open the final implementation, but outlining such implementation with state of the art communication protocols.