Mihaela Gordan

Mihaela Gordan
Universitatea Tehnica Cluj-Napoca | UT Cluj · Department of Communications

PhD

About

78
Publications
10,708
Reads
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391
Citations
Additional affiliations
October 2006 - present
Universitatea Tehnica Cluj-Napoca
Position
  • Professor (Associate)
Description
  • Intelligent Processing and Analysis of Image, Speech and Multimodal Information Research Laboratory (PAIMIV)

Publications

Publications (78)
Article
Background: Assessing the diagnostic value of liver ultrasound image computerized analysis (USICA) for hepatic fibrosis (HF) staging in respect to the "gold standard" provided by liver biopsy (LB). Methods: Two-hundred twenty-eight patients with chronic hepatopathies were prospectively enrolled in the study. All the patients underwent LB and abd...
Conference Paper
The interpretation of data gathered from dam monitoring directly influences the detection of abnormal behaviors. Using previously recorded data, predictive models can be developed, so that the signs of a possible failure are detected as early as possible. The paper presents a multi-step ahead predictive model to generate the values for the horizont...
Conference Paper
Computationally efficient implementation of different image processing and analysis algorithms is crucial in many modern real world applications. Several modern visual analytics applications involve processing large amounts of compressed image/video data on restricted hardware resources, in a numerically efficient manner. In this context, the formu...
Article
Full-text available
Objective: To assess the diagnostic value of a particular set of local intensity parameters extracted from ultrasound liver images in conjunction with support vector machine (SVM) classifiers for liver steatosis grading in respect to the "gold standard" provided by liver biopsy. Material and methods: We prospectively enrolled in the study 228 pa...
Article
Full-text available
In this paper, we present a quantitative analysis of the error in the reconstruction of a 3D scene which has been captured with Synthetic Aperture Integral Imaging system. The 3D information is obtained from 2D images for which the camera parameters are unknown. The model used for calibrating the Integral Imaging camera setup is based on fuzzy syst...
Article
Sparse representations provide a powerful framework for various image processing tasks, among which image recovery seems to be an already classical application. While most developments of image recovery applications are focused on finding the best dictionary, the possibility of using already existing sparse image representations tends to be ignored...
Article
Full-text available
This paper introduces the vanishing points to self-calibrate a structured light system. The vanishing points permit to automatically remove the projector’s keystone effect and then to self-calibrate the projector–camera system. The calibration object is a simple planar surface such as a white paper. Complex patterns and 3D calibrated objects are no...
Article
Full-text available
Contour is an important pattern descriptor in image processing and particularly in region description, registration and length estimation. In many applications where contour is used, a good segmentation and an efficient smoothing method are needed. In X-ray images, such as mammograms, where object edge is not clearly discernible, estimating the obj...
Article
Full-text available
Image filtering is one of the principal tools used in computer vision applications. Real systems store and manipulate high resolution images in compressed forms, therefore the implementation of the entire processing chain directly in the compressed domain became essential. This includes almost always linear filtering operations implemented by convo...
Article
Full-text available
This paper presents a complete solution for the creation and manipulation of the 3D representationof a human face model using off the shelf components. First, the 3D model is obtained bymeans of a structured light system that is calibrated using only the vanishing points extracted from asimple planar surface. Then, an immersive interaction techniqu...
Article
Full-text available
Medical volume segmentation in various imaging modalities using real 3D approaches (in contrast to sliceby-slice segmentation) represents an actual trend. The increase in the acquisition resolution leads to large amount of data, requiring solutions to reduce the dimensionality of the segmentation problem. In this context, the real-time interaction...
Chapter
This paper aims at examining the efficiency of supervised learning methods in the derivation of color correction functions. From the existing supervised learning techniques, some of the most appealing in this field are: neural networks and support vector machines (SVMs) used for regression. In the last decade, SVMs are especially used on a large sc...
Conference Paper
This paper presents a novel method for the calibration of a structured light configuration, which is a particular case of a stereoscopic system in which one of the cameras is replaced by a projector. The method uses vanishing points to remove the keystone effect and to extract the parameters of the projector and of the camera. The calibration is pe...
Conference Paper
Liver segmentation from computer tomography scans is a topic of research interest, as the acquisition and inter-patient variability make the automatic segmentation difficult. The current trend is to improve the accuracy and to reduce the computational complexity of the segmentation, as this is essential for the diagnostic and for 3D rendering. We p...
Article
Ophthalmology is a significant branch of the biomedical field which requires computer-aided automated techniques for pathology identification. Within this framework, an important concern is the accurate segmentation of the retinal blood vessels. A reference approach in the literature to this task consists in the classification of the pixels as vess...
Conference Paper
Full-text available
The perspective projection models the way a 3D scene is transformed into a 2D image, usually through a camera or an eye. In a projective transformation, parallel lines intersect in a point called vanishing point. This paper presents in detail two calibration methods that exploit the properties of vanishing points. The aim of the paper is to offer a...
Conference Paper
The development of computer-aided solutions able to suggest the right facial makeup is a recent trend in image analysis applications, from which both amateurs and professionals could benefit significantly. The global harmony of a person is highly valuable when choosing makeup colors to make a person looking lovely. The global harmony is evaluated t...
Article
Ultrasound imaging remains important for computer aided medical diagnosis. The assessment of hepatic fibrosis from ultrasound images has been investigated in recent works. Fibrosis modifies the liver texture; this is reflected in the hepatic ultrasound image. The existing works report the extraction of different texture features from small regions...
Article
Medical images visualization and interaction is critical for assisted diagnosis and treatment. There are several 3D medical image visualization and interaction frameworks, but no standard tools exist for visual interaction. These tools must gain the user's acceptance, be easy to manipulate and allow a high positioning precision during the interacti...
Chapter
Many median filters are developed for images affected by color impulse noise. A particular approach aims to preserve fine details by noise detection followed by filtering. The color noise detection algorithms vary as principle and performance. This paper proposes a new color image filtering method from this class, which jointly applies two methods...
Article
Full-text available
This paper deals with the calibration of a stereo configuration using two different approaches: a classic perspective projection model and a novel model using fuzzy systems. The two models are mathematically formulated, are calibrated using synthetic data and eventually are compared according to several criteria. The advantages and disadvantages of...
Conference Paper
Median filters are widely used for the reduction of impulse noise in digital images. Since particular problems appear for color images affected by color impulse noise (as color altering or imperfect noise elimination), many color median filtering methods are still developed. Among these, fuzzy median filters are reported to be highly efficient. In...
Article
Water resource management evaluation and planning is an important issue in the context of natural resources management, as it impacts the society, environment, ecology and economy. In the context of the information society, the development of comprehensive decision support components, with the capability of displaying the results of data processing...
Article
Dams are very important economical and social structures that have a great impact on the population living in surrounding area. Dam surveillance is a complex process which involves data acquisition and analysis techniques, implying both measurements from sensors and transducers placed in the dam body and its surroundings, and also visual inspection...
Article
Many existing works in face recognition are based solely on visible images. The use of bimodal systems based on visible and thermal images is seldom reported in face recognition, despite its advantage of combining the discriminative power of both modalities, under expressions or pose variations. In this paper, we investigate the combined advantages...
Article
With the increasing sizes of high resolution images, their storage and processing directly in the compressed domain has significantly gained importance. Algorithms for compressed domain image processing provide a powerful computational alternative to classical (pixel level) based implementations. While linear algorithms can be applied straightforwa...
Article
Full-text available
Hydroelectric energy is a major source of renewable electricity in the world. The industry is continuously searching for ways to improve the efficiency and reliability with which it produces energy. A method based on subtractive clustering of historical data, to develop fuzzy rule-based systems for optimal hydroelectric energy generation allocation...
Conference Paper
Hydro-dams safety represents an important concern since their failure could be critical for the society. A key part of the hydro-dams surveillance programs is their visual inspection. However few computer vision support tools for implementing semi-automatically and objectively the visual surveillance and observation of the hydro-dams components exi...
Conference Paper
This paper proposes a classification scheme of prostate cancer patients based on support vector machines (SVM) classifiers that allow including the diagnosed prostate cancer patients into risk classes, before performing radical prostatectomy, according to their medical parameters. Our objective is to assess the use of SVM in order to predict the in...
Conference Paper
Present energy problems involve issues of technology selection, placement, variation of energy services demand by location and time-of-use and new sourcing options especially renewable energy. Beside these issues, there are also, major challenges for current energy production where the cost and environmental impacts are some of the important aspect...
Conference Paper
The monitoring and behavioral prediction of the hydrodams and hydrotechnical sites relies on the analysis of some objective information, the large number of sensors and examination modalities renders the human inspection of this information very difficult if not even impossible. The main objective of system is to provide a solution to overcome this...
Article
Full-text available
The gold standard for the quantitative evaluation of steatosis is liver biopsy, but this is an invasive method. The recent trend is to investigate and develop novel non-invasive hepatic tissue evaluation methods, able to give performances close to biopsy, one of the possible solutions being ultrasound image analysis. Finding the most suitable descr...
Conference Paper
Full-text available
Cancer classification using high-throughput mass spectrometry data for early disease detection and prevention has recently become an attractive topic of research in bioinformatics. Recently, several studies have shown that the synergy of proteomic technology ...
Article
Full-text available
In the past few years the resolution of images increased and the requirement for large storage space and fast process, directly in the compressed domain, becomes essential. Fuzzy rule-based contrast enhancement, is a well-known rather simple approach with good visual results. As any fuzzy algorithm, it is by default nonlinear, thus not straightforw...
Article
Full-text available
This paper proposes a fast and accurate approach for the identification and quantification of the hepatic fibrosis from liver biopsies using Bayesian tissue classification methods. The approach is based on the pixel level color information, but also on the local texture information in 8×8 pixel neighborhoods, making thus use of the already availabl...
Article
Full-text available
RÉSUMÉ. Les systèmes vidéo utilisés dans l'inspection des parois immergées des barrages utilisent des caméras. Celà confère flexibilité et opérabilité, tout en assurant la stabilité et la précision nécessaires. La présence des sollicitations dynamiques expose les structures aux vibrations mécaniques qui peuvent dégrader leurs performances. Les fréq...
Conference Paper
Hydro dams are very important economical and social structures that have a great impact on the population living in surrounding area. Surveillance of dam status consists of a complex process which involves data acquisition and analysis techniques, implying measurements from sensors and transducers and visual inspection. To enhance the visual inspec...
Conference Paper
Hydro dams are very important economical and social structures that have a great impact on the population living in surrounding area. Surveillance of dam status consists of a complex process which involves data acquisition and analysis techniques, implying measurements from sensors and transducers and visual inspection. To enhance the visual inspec...
Conference Paper
Full-text available
Visual surveillance of underwater parts of hydro-dams is a task where computer vision techniques can be of great help. Few such systems are currently reported. The image analysis is difficult for underwater images due to their variable lighting, blurring and poor contrast. A good image segmentation procedure is needed but often hard to define. We p...
Article
Full-text available
Our objective is to investigate image processing directly in the compressed domain, without full decompression. Compressed domain image processing algorithms provide a powerful computational alternative to classical (pixel level) based implementations. The field is just emerging and the algorithms reported in the literature are mostly based on line...
Article
Underwater images analysis is a difficult task due to their specific attributes: weak and variable lighting, low contrast, blurring. Therefore powerful image analysis algorithms, application specific, must be employed to obtain good results. In this paper we propose such a novel architecture based on a support vector machine (SVM) classifier, dedic...
Article
Support vector machines (SVMs) are powerful classifiers, with very good recognition rates in image analysis tasks. However their computational time in the object recognition phase is often large due to the number of classifications per scene and to the feature vector size, especially when the feature space is formed from raw image data. Several met...
Conference Paper
Full-text available
The perceived latency for a user surfing the Internet is the target of a transparent and speculative algorithm that relies on a user behavior model. The model is based on past user behavior and in combination with a weighting scheme for the outbound links of a particular web page, aims at reducing the perceived latencies. The assistance is in the f...
Article
Full-text available
The visual examination of downstream faces of hy- dro - dams is an important component in their monitoring. Few computer vision algorithms exist for this task. Some of them aim to detect and eval- uate concrete cracks using edge detection. Other problems can also affect hydro-dams, as roughness, scratches, and can lead in time to surface deterio- r...
Article
Full-text available
The classification task in large data spaces can now relay on newly developed Support Vector Machine technique. A trade-off between the hardware complexity and processing time is a partially sequential – partially parallel implementation of the processing issues based on a description of the vectors as time-continuous signals. We present an analog...
Conference Paper
Full-text available
Support vector machines (SVMs) are powerful classifiers for large tasks as image/video-sequence analysis. A practical implementation issue for such problems is their real time operation in the classification phase. One recent strategy is the development of algorithmic formulation of SVMs suitable for hardware implementation. We propose such an appr...
Article
Full-text available
In this paper a variant of the well-known self-organizing map algorithm is exploited for document organization and retrieval. An ensemble of self-organizing maps are em-ployed in an effort to boost the performance of the stan-dard algorithm. In doing so, the feature space is uniformly sampled and the bootstrapped sets that are created are sup-plied...
Conference Paper
Full-text available
Support vector machines (SVMs) are powerful classifiers for large tasks as image/video-sequence analysis. A practical implementation issue for such problems is their real time operation in the classification phase. One recent strategy is the development of algorithmic formulation of SVMs suitable for hardware implementation. We propose such an appr...
Conference Paper
This paper present some image processing algoritms implementated in the frame of ANGIODOP Project financed by VIASAN-Romanian R&D program
Article
Full-text available
Visual speech recognition is an emerging research field. In this paper, we examine the suitability of support vector machines for visual speech recognition. Each word is modeled as a temporal sequence of visemes corresponding to the different phones realized. One support vector machine is trained to recognize each viseme and its output is converted...
Article
Visual speech recognition is an emerging research field. In this paper, we examine the suitability of support vector machines for visual speech recognition. Each word is modeled as a temporal sequence of visemes corresponding to the different phones realized. One support vector machine is trained to recognize each viseme and its output is converted...
Article
Full-text available
In this paper we propose a visual speech recognition network based on Support Vector Machines. Each word of the dictionary is described as a temporal sequence of visemes. Each viseme is described by a support vector machine, and the temporal character of speech is modeled by integrating the support vector machines as nodes into a Viterbi decoding l...
Article
In the relatively large class of lipreading algorithms based on lip contour analysis, lip contour extraction is the first step. This refers to the detection of lip contour in the first frame of an audio-visual sequence, where no initial prediction of the lip contour is available. This task is usually solved manually or pseudo-automatically, requiri...
Article
Full-text available
The problem of lip contour detection is critical in the lipreading systems based on contour processing. The typical contour detection strategy based on image segmentation in homogeneous regions fails in the case when the mouth images available for lipreading are lowcontrast gray level images. Most of the solutions adopted require manual marking of...
Article
Full-text available
In this paper we proposed a visual speech recognition network based on Support Vector Machines. Each word of the dictionary is modeled by a set of temporal sequences of visemes. Each viseme is described by a support vector machine, and the temporal character of speech is modeled by integrating the support vector machines as nodes into Viterbi decod...
Article
Full-text available
One of the widely used algorithms for data clustering and image segmentation is the fuzzy c-means (FCM) algorithm. The objective function minimization in FCM guarantees the optimal data separation according to their feature values but there is no guarantee that this separation will match an available ground truth. However an optimal feature set can...
Conference Paper
Full-text available
Speech recognition based on visual information is an emerging research field. We propose here a new system for the recognition of visual speech based on support vector machines which proved to be powerful classifiers in other visual tasks. We use support vector machines to recognize the mouth shape corresponding to different phones produced. To mod...
Conference Paper
In this paper we propose a visual speech recognition network based on support vector machines. Each word of the dictionary is modeled by a set of temporal sequences of visemes. Each viseme is described by a support vector machine, and the temporal character of speech is modeled by integrating the support vector machines as nodes into a Viterbi deco...
Conference Paper
Full-text available
Detection and tracking of the lip contour is an important issue in lipreading. While there are solutions for lip tracking once a good contour initialization in the first frame is available, the problem of finding such a good initialization is not yet solved automatically, but done manually. Solutions based on edge detection and tracking have failed...
Article
Full-text available
The open-loop gain of a typical two-stage transistor voltage-feedback amplifier is put in the form of a ratio between its value in the absence of feedback components and the product of two gain-degrading factors. Minimising this product results in maximising the open-loop gain, and the corresponding algebra is much less laborious than the one in th...
Conference Paper
Full-text available
The aim of the paper is to present a fuzzy method for the optimization of the CMOS operational amplifier design. Our method uses fuzzy systems or fuzzy sets in all stages involved in the optimization process. In order to reduce the time spent for circuit performance evaluation, we use fuzzy system to model each circuit performance. The optimization...
Article
Full-text available
A new method to deduce the voltage transfer characteristic for two-port networks containing bias sources is presented. The method allows the deduction of the transfer characteristic only by translating a known transfer characteristic in the input voltage-output voltage plane; this way the analysis of the whole circuit is no longer necessary. Also t...
Article
Full-text available
An important application of fuzzy logic systems is the approximation of non-linear curves. This application has been successfully used in device modeling based on their response to one input stimulus; an example is the I(VD) characteristic modeling for a diode [3]. In this paper we propose a generalisation of the fuzzy modeling from [3] to the mode...
Conference Paper
In today's digital circuit simulators, the voltages during the transition time are only qualitatively described. We propose here a fuzzy logic model for the TTL inverter which quantitatively describes both its static and dynamic voltage behavior, according to its double slope voltage transfer characteristic. This model can also be viewed as a basic...