672 research outputs found
Modelli e metodi per la ricostruzione degli incidenti stradali
No full textVengono illustrati i metodi ed i modelli matematici per la ricostruzione di alcune tipologie di incidenti stradali: urto frontale tra autovetture, urto obliquo tra autovetture, incidenti con motocicli, incidenti con velocipede, incidenti con pedoni
Ricostruzione della cinematica interna di un veicolo tamponato
No full textViene illustrata una modalità di calcolo delle accelerazioni subite dagli occupanti di un veicolo tamponato, necessaria per verificare la sussistenza di efficacia lesiva
Palmprint Recognition Through a Reliable Ultrasound Acquisition System and a 3D Template
No full textBiometric systems based on ultrasonic images have the merits of being very resistent to spoof attacks. In this work, a 3D recognition procedure based on palmprint ultrasound images acquired through a reliable system, which uses a gel pad as coupling medium between the ultrasound probe and the hand, is proposed and experimentally evaluated. Several 2D palmprint images, at different under-skin depths, are extracted from the acquired volumetric image. For each of them a template is generated through an original procedure. The various templates are then opportunely combined to obtain a 3D template
Fusion Analysis of a Palmprint-Hand Geometry Multimodal Ultrasound Recognition System
No full textMultimodal biometric systems are employed in several application fields due to series of advantages in terms of universality and recognition rate. Compared to other technologies, Ultrasound has many advantages, because it allows to obtain 3D images of human body and to verify liveness. In this work, a multimodal ultrasound recognition system based on the fusion of palmprint and hand geometry is proposed and experimentally evaluated. Volumetric hand images are acquired by using water as coupling medium and 2D rendering are obtained at various depth levels. Successively, 2D and 3D features are extracted both for palmprint and hand-geometry. Recognition performances are evaluated through verification experiments by employing a homemade database, first by considering the single characteristics and successively by fusing them. Results demonstrated a drastic improving of results with the fusion but not necessarily the best fusion result is obtained by considering the best palmprint and hand geometry
Experimental validation of a reliable palmprint recognition system based on 2D ultrasound images
No full textUltrasound has been trialed in biometric recognition systems for many years, and at present different types of ultrasound fingerprint readers are being produced and integrated in portable devices. An important merit of the ultrasound is its ability to image the internal structure of the hand, which can guarantee improved recognition rates and resistance to spoofing attacks. In addition, ambient noise like changes of illumination, humidity, or temperature, as well as oil or ink stains on the skin do not affect the ultrasound image. In this work, a palmprint recognition system based on ultrasound images is proposed and experimentally validated. The system uses a gel pad to obtain acoustic coupling between the ultrasound probe and the user’s hand. The collected volumetric image is processed to extract 2D palmprints at various under-skin depths. Features are extracted from one of these 2D palmprints using a line-based procedure. Recognition performances of the proposed system were evaluated by performing both verification and identification experiments on a home-made database containing 281 samples collected from 32 different volunteers. An equal error rate of 0.38% and an identification rate of 100% were achieved. These results are very satisfactory, even if obtained with a relatively small database. A discussion on the causes of bad acquisitions is also presented, and a possible solution to further optimize the acquisition system is suggested
A Feasible 3D Ultrasound Palmprint Recognition System for Secure Access Control Applications
Get PDFBiometric recognition systems based on 3D palmprint captured with optical technology have been widely investigated in the last decade; however, they can provide information about the external skin surface only. This limit can be overcome by Ultrasound, which allows gaining information on the depth of palm lines and can verify the liveness of the sample, making the recognition systems very hard to fake. In this work, a feasible palmprint recognition system based on 3D ultrasound images is proposed. Unlike previous wet setups, the coupling between probe and human is realized through a gel pad, which permits a comfortable and precise positioning of the hand by the user. Collected 3D images are processed to generate 2D palmprint images at various under-skin depths. 2D features are then extracted from these images, experimenting with different procedures, and are merged to define a 3D template that contains lines' depth information. Recognition performances were evaluated by performing verification and identification experiments on a home-made database composed of 423 samples from 55 volunteers. An EER rate of 0.36% and an identification accuracy of 100% are obtained. The suitability of the proposed system in secure access control applications is finally discussed
Recognition Performance Analysis of a Multimodal Biometric System Based on the Fusion of 3D Ultrasound Hand-Geometry and Palmprint
Get PDFMultimodal biometric systems are often used in a wide variety of applications where high security is required. Such systems show several merits in terms of universality and recognition rate compared to unimodal systems. Among several acquisition technologies, ultrasound bears great potential in high secure access applications because it allows the acquisition of 3D information about the human body and is able to verify liveness of the sample. In this work, recognition performances of a multimodal system obtained by fusing palmprint and hand-geometry 3D features, which are extracted from the same collected volumetric image, are extensively evaluated. Several fusion techniques based on the weighted score sum rule and on a wide variety of possible combinations of palmprint and hand geometry scores are experimented with. Recognition performances of the various methods are evaluated and compared through verification and identification experiments carried out on a homemade database employed in previous works. Verification results demonstrated that the fusion, in most cases, produces a noticeable improvement compared to unimodal systems: an EER value of 0.06% is achieved in at least five cases against values of 1.18% and 0.63% obtained in the best case for unimodal palmprint and hand geometry, respectively. The analysis also revealed that the best fusion results do not include any combination between the best scores of unimodal characteristics. Identification experiments, carried out for the methods that provided the best verification results, consistently demonstrated an identification rate of 100%, against 98% and 91% obtained in the best case for unimodal palmprint and hand geometry, respectively
Trazione stradale e ferroviaria. Infortunistica stradale e ferroviaria. Trasporti con veicoli individuali a guida automatica.
No full textTrazione stradale e ferroviaria: in ambito stradale vengono esaminate problematiche relative al moto di unità di trasporto su suolo sconnesso o su traiettorie articolate; in ambito ferroviario vengono studiate le resistenze al moto incontrate da rotabili ferroviari merci di nuova generazione.
Infortunistica stradale e ferroviaria: la linea di ricerca riguarda in ambito stradale l’interazione esterna uomo-macchina, con particolare focalizzazione sull’utente debole, di cui si analizzano le modalità di investimento in funzione delle varie geometrie dei veicoli, nonché della velocità relativa, con l’obiettivo di giungere a relazioni empiriche descrittive del moto descritto; in ambito ferroviario l’attenzione è concentrata sui regolamenti.
Trasporti con veicoli individuali a guida automatica: Obiettivo generale della ricerca proposta è lo sviluppo di nuovi metodi per ottimizzare la gestione, e la pianificazione di una rete di trasporto pubblico di tipo Personal Rapid Transit (PRT)
Multimodal Biometric Recognition Based on 3D Ultrasound Palmprint-Hand Geometry Fusion
Get PDFIn recent years, multimodal biometric systems are increasingly employed in many application field due to several advantages in terms of universality, recognition rate. and security. Among various acquisition technologies, Ultrasound shows important merits, because it allows obtaining volumetric images of the human body and hence a more accurate description of characteristics and to verify liveness. In this work, a multimodal ultrasound recognition system based on the fusion between 3D hand geometry and 3D palmprint features is proposed and experimentally evaluated. The system acquires a volumetric image of the whole hand and for both characteristics, several 2D images are extracted at different depth levels. From each image, 2D features are extracted and then properly combined to achieve a 3D template. Recognition performances are evaluated through verification and identification experiments by employing a homemade database. Experiments are carried out first for the two unimodal biometrics and successively, by fusing the two modalities at score level. Results have shown that fusion is able to dramatically improve the recognition performances of the single biometrics, achieving an Equal Error Rate of 0.08% and an identification rate of 100%
Analisi sperimentale della circolazione del ciclista
No full textVengono relazioni gli esiti di una campagna sperimentale di rilevamento della condotta di guida dei ciclisti in ambito urbano
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