Language Dependency of Speaker Recognition Systems

One of many possible biometric identification methods is voice recognition. A voice recording can be compared to a suspect sample to determine whether suspect and perpetrator are the same. Often the necessary materials are not all available in the same language. This aspect called cross-language speaker recognition can make identification much more challenging. It is therefore fundamental to ensure that the systems used, can correctly perform the assessment in cross-language situations. This paper compares two systems used for biometric speaker recognition that both support cross language identification. The first tool is the BatVOX system, made by Agnitio corp. The second system is Nuance Forensics, made by Nuance. Several contradictions concerning language dependence have been seen. In some situations the language match test performs better than the language mismatch test, while this has been seen the other way around as well. In general the Nuance system seems to be slightly better, however nothing can be said about the language dependency of both systems. It is recommended to obtain more data from both languages in order to make a proper comparison

Likelihood ratio calibration in a transparent and testable forensic speaker recognition framework

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. D. Ramos, J. González-Rodríguez, J. Ortega-garcía, "Likelihood Ratio Calibration in a Transparent and Testable Forensic Speaker Recognition Framework " in The Speaker and Language Recognition Workshop, ODYSSEY, San Juan (Puerto Rico), 2006, 1 - 8A recently reopened debate about the infallibility of some classical forensic disciplines is leading to new requirements in forensic science. Standardization of procedures, proficiency testing, transparency in the scientific evaluation of the evidence and testability of the system and protocols are emphasized in order to guarantee the scientific objectivity of the procedures. Those ideas will be exploited in this paper in order to walk towards an appropriate framework for the use of forensic speaker recognition in courts. Evidence is interpreted using the Bayesian approach for the analysis of the evidence, as a scientific and logical methodology, in a two-stage approach based in the similarity-typicality pair, which facilitates the transparency in the process. The concept of calibration as a way of reporting reliable and accurate opinions is also deeply addressed, presenting experimental results which illustrate its effects. The testability of the system is then accomplished by the use of the NIST SRE 2005 evaluation protocol. Recently proposed application-independent evaluation techniques (Cllr and APE curves) are finally addressed as a proper way for presenting results of proficiency testing in courts, as these evaluation metrics clearly show the influence of calibration errors in the accuracy of the inferential decision processThis work has been supported by the Spanish Ministry for Science and Technology under project TIC2003-09068-C02-01

Automatinio asmens atpažinimo iš balso problemos ir perspektyvos kriminalistikoje.

Technologies of speaker recognition by voice in criminology were applied recently. Now they become topical in many countries. Main methods, used in automatic speaker recognition by voice were considered in this article. Analysis of forensic speaker identification by voice and automatic identification system was performed. Outlook of novel automatic speaker recognition systems in forensic inspection, criminal search and strategical work were discussed. Results of automatic speaker identification evaluation, using database were described. Conclusion can be made, that automatic speaker recognition system is convenient, because it requires minimal knowledge from the user. This system can by applied in criminal search, but it has limitations in forensic inspection. One of the most important lack of automatic speaker recognition systems is less accuracy of recognition and relatively long record length is required for training and testing of the system. In spite of lack of automatic recognition system, some methods that are used in this system can be applied in combined system. And how our and other countries experience shows, it allows to perform research rather and more objective. One of the most promising way could be development of the database, consisting of voice records and integrated automatic recognition system, what would allow to perform not only automatic speaker recognition, but finding test and template records too, and so on.Straipsnyje apžvelgti pagrindiniai metodai, šiuo metu taikomi automatiniam asmens atpažinimui iš balso, ir atlikta teisminio asmens identifikavimo iš balso ir automatinio asmens identifikavimo sistemų analizė. Nagrinėjamos naujų automatinių asmens atpažinimo sistemų taikymo perspektyvos teismo ekspertizėje ir kriminalinėje paieškoje bei operatyviniame darbe. Pateikiami automatinio asmens identifikavimo rezultatai, naudojant balsų bazę. Gautų rezultatų pagrindu daroma išvada - automatinio asmens atpažinimo iš balso sistema yra gana patogi vartotojui, nes ji iš vartotojo reikalauja minimalių žinių. Tokia sistema gali būti taikoma vykdant kriminalinę paiešką, tačiau atliekant teismo ekspertizę jos taikymas yra ribotas

Quality-Based Conditional Processing in Multi-Biometrics: Application to Sensor Interoperability

As biometric technology is increasingly deployed, it will be common to replace parts of operational systems with newer designs. The cost and inconvenience of reacquiring enrolled users when a new vendor solution is incorporated makes this approach difficult and many applications will require to deal with information from different sources regularly. These interoperability problems can dramatically affect the performance of biometric systems and thus, they need to be overcome. Here, we describe and evaluate the ATVS-UAM fusion approach submitted to the quality-based evaluation of the 2007 BioSecure Multimodal Evaluation Campaign, whose aim was to compare fusion algorithms when biometric signals were generated using several biometric devices in mismatched conditions. Quality measures from the raw biometric data are available to allow system adjustment to changing quality conditions due to device changes. This system adjustment is referred to as quality-based conditional processing. The proposed fusion approach is based on linear logistic regression, in which fused scores tend to be log-likelihood-ratios. This allows the easy and efficient combination of matching scores from different devices assuming low dependence among modalities. In our system, quality information is used to switch between different system modules depending on the data source (the sensor in our case) and to reject channels with low quality data during the fusion. We compare our fusion approach to a set of rule-based fusion schemes over normalized scores. Results show that the proposed approach outperforms all the rule-based fusion schemes. We also show that with the quality-based channel rejection scheme, an overall improvement of 25% in the equal error rate is obtained.Comment: Published at IEEE Transactions on Systems, Man, and Cybernetics - Part A: Systems and Human

Forging a Stable Relationship?: Bridging the Law and Forensic Science Divide in the Academy

The marriage of law and science has most often been represented as discordant. While the law/science divide meme is hardly novel, concerns over the potentially deleterious coupling within the criminal justice system may have reached fever pitch. There is a growing chorus of disapproval addressed to ‘forensic science’, accompanied by the denigration of legal professionals for being unable or unwilling to forge a symbiotic relationship with forensic scientists. The 2009 National Academy of Sciences Report on forensic science heralds the latest call for greater collaboration between ‘law’ and ‘science’, particularly in Higher Education Institutions (HEIs) yet little reaction has been apparent amid law and science faculties. To investigate the potential for interdisciplinary cooperation, the authors received funding for a project: ‘Lowering the Drawbridges: Forensic and Legal Education in the 21st Century’, hoping to stimulate both law and forensic science educators to seek mutually beneficial solutions to common educational problems and build vital connections in the academy. A workshop held in the UK, attended by academics and practitioners from scientific, policing, and legal backgrounds marked the commencement of the project. This paper outlines some of the workshop conclusions to elucidate areas of dissent and consensus, and where further dialogue is required, but aims to strike a note of optimism that the ‘cultural divide’ should not be taken to be so wide as to be beyond the legal and forensic science academy to bridge. The authors seek to demonstrate that legal and forensic science educators can work cooperatively to respond to critics and forge new paths in learning and teaching, creating an opportunity to take stock and enrich our discipline as well as answer critics. As Latham (2010:34) exhorts, we are not interested in turning lawyers into scientists and vice versa, but building a foundation upon which they can build during their professional lives: “Instead of melding the two cultures, we need to establish conditions of cooperation, mutual respect, and mutual reliance between them.” Law and forensic science educators should, and can assist with the building of a mutual understanding between forensic scientists and legal professionals, a significant step on the road to answering calls for the professions to minimise some of the risks associated with the use of forensic science in the criminal process. REFERENCES Latham, S.R. 2010, ‘Law between the cultures: C.P.Snow’s The Two Cultures and the problem of scientific illiteracy in law’ 32 Technology in Society, 31-34. KEYWORDS forensic science education legal education law/science divid