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1
Content available An accurate fingerprint reference point determination method based on curvature estimation of separated ridges
Doroz R., Wrobel K., Porwik P.
International Journal of Applied Mathematics and Computer Science
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2018
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Vol. 28, no. 1
209--225
EN
This paper presents an effective method for the detection of a fingerprint’s reference point by analyzing fingerprint ridges’ curvatures. The proposed approach is a multi-stage system. The first step extracts the fingerprint ridges from an image and transforms them into chains of discrete points. In the second step, the obtained chains of points are processed by a dedicated algorithm to detect corners and other points of highest curvature on their planar surface. In a series of experiments we demonstrate that the proposed method based on this algorithm allows effective determination of fingerprint reference points. Furthermore, the proposed method is relatively simple and achieves better results when compared with the approaches known from the literature. The reference point detection experiments were conducted using publicly available fingerprint databases FVC2000, FVC2002, FVC2004 and NIST.
2
Content available Hybrid verification method based on finger-knuckle analysis and keystroke dynamics
Wesolowski T. E., Safaverdi H., Doroz R., Wrobel K.
Journal of Medical Informatics & Technologies
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2017
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Vol. 26
26--36
EN
The increasing number of personal data leaks becomes one of the most important security issues hence the need to develop modern computer user verification methods. In the article, a potential of biometric methods fusion for continuous user verification was assessed. A hybrid approach for user verification based on fusion of keystroke dynamics and knuckle images analysis was presented. Verification is performed by a classification module where an ensemble classifier was used to verify the identity of a user. A proposed classifier works on a database which comprises of knuckle images and keyboard events for keystroke dynamics. The proposed approach was tested experimentally. The obtained results confirm that the proposed hybrid approach performs better than methods based on single biometric feature hence the introduced method can be used for increasing a protection level of computer resources against forgers and impostors. The paper presents results of preliminary research conducted to assess the potential of biometric methods fusion.
3
Content available Personal identity verification method based on lips photographs
Wrobel K., Doroz R., Porwik P., Naruniec J., Kowalski M.
Journal of Medical Informatics & Technologies
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2015
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Vol. 24
59--65
EN
The paper presents a personal identification method based on lips photographs. This method uses a new approach to the extraction and classification of characteristic features of the mouth from photographs. It eliminates the drawbacks that occur during the acquisition of lip print images with the use of the forensic method that requires special tools. Geometrical dimensions of the entire mouth as well as of the upper and lower lips were adopted as the features, on the basis of which the verification is performed. An ensemble classifier was used for the classification of the features obtained. The effectiveness of the classifier has been verified experimentally.
4
Content available Person verification based on keystroke dynamics
Doroz R., Porwik P., Safaverdi H.
Journal of Medical Informatics & Technologies
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2015
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Vol. 24
39--44
EN
This paper presents a new multilayer ensemble of classifiers for users verification who use computer keyboard. The special keyboard extracts the key pressure and latency between keyboard keys pressed during password entered. When user is typing password the system creates a pattern based on time and key pressure. For users verification group of classifiers have been proposed. It allows to obtain the higher accuracy level compared to alternative techniques. The efficiency of the proposed method has been confirmed in the experiments carried out.
5
Content available Determining valuable ranges of handwritten signature using fuzzy approach and window method
Kudłacik P., Doroz R.
Journal of Medical Informatics & Technologies
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2015
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Vol. 24
23--30
EN
The paper proposes possible improvements in signature recognition approach based on window method. The analysis focuses on a stage of window preprocessing using fuzzy sets in order to choose significant ranges of each signature. Proposed extension allows the solution to improve in two areas. First of all minimizing a number of processed windows significantly reduces computation time. Secondly, filtered signatures with valuable information about significant ranges allow the system to recognize signatures of a poor or good quality. Developed method of signature quality assessment can be used in any signature recognition system, regardless of used method of analysis. Merging the information about signature quality and choosing only important signature ranges should also improve the overall detection results, however, more examinations are needed to confirm this statement.
6
Content available Method of signature recognition with the use of the complex features
Doroz R., Pałys M., Orczyk T., Safaverdi H.
Journal of Medical Informatics & Technologies
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2014
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Vol. 23
155--162
EN
In this paper a new method of handwritten signatures verification has been proposed. This method, for each signature, creates complex features which are describing this signature. These features are based on dependencies analysis between dynamic features registered by tablets. These complex features are then used to create vectors describing the signature. Elements of these vectors are calculated using measures proposed in this work. The similarity between signatures is assessed by determining the similarity of vectors in the compared signatures. Research, whose results will be presented in the further part of this work, have shown a high efficiency of verification using proposed method.
7
Content available Method for identification of fragments of lip prints images on the basis of the generalized hough transform
Wrobel K., Doroz R.
Journal of Medical Informatics & Technologies
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2013
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Vol. 22
189--193
EN
The paper presents a new method for identification of fragments of lip print images on the basis of the Generalized Hough Transform (GHT). The effectiveness of this method was verified in practice. The maximum value obtained from the accumulator array after the Hough transform has been assumed as the measure of similarity between a lip print image and a reference object. The advantage of this method is the possibility of use in forensic science to identify persons who left lip prints at crime scenes.
8
Content available Using hidden Markov models in signature recognition process
Doroz R., Wróbel K.
Journal of Medical Informatics & Technologies
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2012
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Vol. 21
75--84
EN
This paper presents a method of recognition of handwritten signatures with the use of Hidden Markov Models (HMM). The method in question consists in describing each signature with a sequence of symbols. Sequences of symbols were generated on the basis of an analysis of local extremes determined on diagrams of dynamic features of signatures. For this purpose, the method proposed by G.K. Gupta and R.C. Joyce has been modified. The determined sequences were then used as input data for the HMM method. The studies were conducted with the use of the SVC2004 database. The results are competitive in relation to other methods known from the literature.
9
Content available The use of methods of statistical analysis in signature recognition system based on Levenshtein distance
Pałys M., Doroz R., Porwik P.
Journal of Medical Informatics & Technologies
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2012
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Vol. 21
67--73
EN
The study being presented is a continuation of the previous studies that consisted in the adaptation and use of the Levenshtein method in a signature recognition process. Three methods based on the normalized Levenshtein measure were taken into consideration. The studies included an analysis and selection of appropriate signature features, on the basis of which the authenticity of a signature was verified later. A statistical apparatus was used to perform a comprehensive analysis. The independence test ◈ was applied. It allowed determining the relationship between signature features and the error returned by the classifier.
10
Content available The method of signature recognition based on least squares contour alignment and windows technique
Wróbel K., Doroz R.
Journal of Medical Informatics & Technologies
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2010
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Vol. 15
35--39
EN
This paper presents a new method of recognizing handwritten signatures. Signature was treated as a collection of features of specific values. As features the values of x, y coordinates of signature points have been used. The method discussed in the paper is a modification of the method based on least squares contour alignment. This modification consists of dividing signatures into windows of the preset size and measuring the value of similarity between the windows according to their position in the signature. The effectiveness of the method was verified in practice. During the study, the influence of the parameters of the method on the obtained results was determined.
11
Content available The method for determining the characteristic points of signatures based on IPAN99 algorithm
Doroz R., Kostorz I.
Journal of Medical Informatics & Technologies
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2010
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Vol. 15
41-46
EN
The paper puts forward a new method of determination of signatures' characteristic points. The method is based on seeking points of the highest curvature using the IPAN99 algorithm. The way of IPAN99 algorithm parameters' automatic selection for a particular signature has been fully described. Moreover, the way of determination of additional characteristic points, important for a signatures analysis, has been shown. The presented results of carried out experiments confirm that the proposed method is useful for signature recognition and verification.
12
Content available Biometric recognition system based on the motion of the human body gravity centre analysis
Porwik P., Zyguła J., Doroz R., Proksa R.
Journal of Medical Informatics & Technologies
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2010
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Vol. 15
61-69
EN
In this paper we present a novel approach that enables the determination and measurement of important features associated with the human body movement. This information can be used in the construction of a biometric personal identification system. Biometrics is, essentially, a pattern recognition system based on measurements of unique physiological or behavioural features as acquired from an individual. The domain of biometric techniques is currently placed within recently developed disciplines of science. Biometry or biometrics is simply defined as automatically recognizing a person using distinguishing traits and is widely used in various security systems. Biometry can be defined as a method of personal identification based on individuals' physical and behavioural features. Physiological biometrics covers data coming directly from a measurement of part of a human body, for example a fingerprint, the shape of the face, or from the retina. Behavioural biometrics analyses data obtained on the basis of an activity performed by a given person, for example speech and the handwritten signature. The system of biometrics defined above can now be expanded, and a new biometrics system can be considered. In our approach, human foot pressure on a surface is measured and the pressure data retrieved. The pressure parameters are collected without the necessity of any movements of the feet.
13
Content available Signatures recognition method by using the normalized Levenshtein distances
Doroz R., Wróbel K., Porwik P.
Journal of Medical Informatics & Technologies
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2009
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Vol. 13
73--77
EN
This study examines the effectiveness of normalized Levenshtein metrics in the process of recognition of handwritten signatures. Three methods of normalization of the Levenshtein metric were taken into consideration. In addition, it was determined, which signature features are most important during their comparisons with the use of the aforementioned metric. The following signature features were examined: coordinates of signature points, pen pressure in successive points, and different types of pen speed. The influence of individual parameters of the Levenshtein algorithm on the obtained results was also determined, and the best method of normalization was selected.
14
Content available New method for finding a reference point in fingerprint images with the use of the IPAN99 algorithm
Wróbel K., Doroz R.
Journal of Medical Informatics & Technologies
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2009
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Vol. 13
59--63
EN
This study presents a new method for finding a reference point in fingerprint images. The proposed method is based on the IPAN99 algorithm, which detects high curvature points on a contour of a graphical object. This algorithm was adjusted in the study to detect high curvature points on friction ridges. It allows locating a reference point on a fingerprint image. Since the IPAN99 algorithm requires that the thickness of an analysed contour should be of one pixel, each fingerprint image was adequately prepared before submitting to the analysis with the IPAN99 algorithm. Evaluation of the efficiency of the method consisted in comparing the distances between coordinates of reference points determined with the use of the proposed method and indicated by an expert. The developed method was compared with other algorithms used for determining a reference point.
15
Content available On some optimalization of signature recognition
Doroz R., Bargielski M.J.
Journal of Medical Informatics & Technologies
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2008
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Vol. 12
201--206
EN
Signature recognition is one of the important problems nowadays. In paper we present known method of pattern (curves) recognition, i.e. algorithm IPAN99 and researches over its optimization; there are many control parameters which influence on recognition results. We present some quasi-optimal set of control parameter. Our next aim is to automatically find proper parameters. Thus some optimum seeking method for unimodale and multimodale function is proposed.
16
Content available New signature similarity measure based on average differences
Wróbel K., Doroz R.
Journal of Medical Informatics & Technologies
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2008
|
Vol. 12
51--56
EN
This paper presents a new method of recognizing handwritten signatures. Signature was treated as a collection of features of specific values. As features the values of x, y coordinates of signature points and the pressure p in its consecutive points have been used. Additionally, before comparing them, the signatures were properly prepared. The method discussed in the paper is a modification of the method based on average differences. This modification consists in dividing signatures into windows of the preset size and measuring the value of similarity between the windows according to their position in the signature. The paper shows the construction of a new similarity measure taking into consideration the modifications introduced and the results of the research obtained by means of this similarity measure.
17
Content available New methods to determine similarity of signatures based on local extremes
Doroz R., Mitas M.
Journal of Medical Informatics & Technologies
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2008
|
Vol. 12
63--67
EN
Authentication based on handwritten signature is one of the most accepted authentication systems based on biometry. In this paper a method for the automatic verification of on-line handwritten signatures using three similarity measures is described. The proposed approach, is based on extreme values and dynamic features of the signature. In investigations proposed coefficients together with the factor [R2] were connected and new signature recognition quality has been achieved.
18
Content available Signature characteristic points determination by means of the IPAN99 algorithm
Doroz R., Widuch S.
Journal of Medical Informatics & Technologies
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2007
|
Vol. 11
105--113
EN
The handwritten signature is often used for the identity confirmation. From the specialized graphic tablet, we receive the information in form of time strings. In this paper, the research results are presented which refer to the effect of applying the method of point detection of the highest curvature. Signatures are normalized by means of a DTW method, where two time strings representing the signature features are matched.
19
The method of preliminary medical images selection
Porwik P., Wróbel K., Widuch S., Doroz R.
Journal of Medical Informatics & Technologies
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2001
|
Vol. 2, Part. 1
MI169--MI176
EN
This work investigates the use of some features computed using the Hough Transform as a criterion for image similarity evaluation based on picture retrieval. The method is based on a modified Hough Transform and used to approximate edges detected in the input image with straight lines. We consider retrieving images from a thematic database, where the semantic contents of images is limited to a specific domain (for example medical images). Proposed analysis of images does not claim that all features will be used, but special selection of features is well suited for evaluating of the visual coherence of images. In the first stage line elements are extracted from the image by using Hough Transform. In the second stage similarity coefficients are computed.
20
Content available remote Wskazniki jakości sterowania sygnalizacją świetlną w systemie "OPTYMAL"
Doroz R., Wąsik R., Widuch S.
Zeszyty Naukowe. Transport / Politechnika Śląska
|
2000
|
z. 41
127-138
PL
Przedstawiono najczęściej stosowane wskaźniki umożliwiające ocenę jakości sterowania skrzyżowaniem ulic będącym jednym z krytycznych elementów sieci transportowej miasta, decydującym w dużym stopniu o jej przepustowości. Omówiono także nowy system komputerowego wyboru optymalnych harmonogramów sterowania sygnalizacją świetlną na skrzyżowaniu.
EN
The paper several aspects of simulation of the "OPTYMAL" package, developed in Institute of Transport. The quality factors of traffic control procedures have been discused in the paper as well.
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