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Preface [chapter]

Kresimir Delac, Mislav Grgic
2007 Face Recognition  
How to reference In order to correctly reference this scholarly work, feel free to copy and paste the following: Kresimir Delac and Mislav Grgic (2007) .  ...  of Electrical Engineering and Computing Department of Wireless Communications Unska 3/XII, HR-10000 Zagreb, Croatia Face Recognition Edited by Kresimir Delac and Mislav Grgic ISBN 978-3-902613  ... 
doi:10.5772/4856 fatcat:7slm3uxjnre55kqhtm677ygmra

Image Compression Effects in Face Recognition Systems [chapter]

Kresimir Delac, Mislav Grgic, Sonja Grgic
2007 Face Recognition  
Figure 2 Similar conclusions on JPEG and JPEG2000 efficiency can be found in (Grgic et al., 2001) .  ...  Grgic, ISBN 978-3-902613-03-5, pp.558, I-Tech, Vienna, Austria, June 2007 Open Access Database www.i-techonline.com Face Recognition 76 and testing stage (Delac, 2006) .  ...  How to reference In order to correctly reference this scholarly work, feel free to copy and paste the following: Kresimir Delac, Mislav Grgic and Sonja Grgic (2007) .  ... 
doi:10.5772/4832 fatcat:jvuz6ahtbndd5jb4wxsrvbjmim

SCface – surveillance cameras face database

Mislav Grgic, Kresimir Delac, Sonja Grgic
2009 Multimedia tools and applications  
In this paper we describe a new method of likelihood ratio computation for score-based biometric recognition systems given a small number of samples in the within-source variability dataset (also called target set). Generally the number of samples in the withinsource variability dataset is less than the number of samples in the between-source variability dataset (also called non-target set) and therefore the probability density function (pdf) of the within-source variability dataset cannot be
more » ... timated reliably compared to the pdf of the between-source variability. The proposed method estimates the pdf of within-source variability from estimates of the within-source variability mean and variance and the pdf of between-source variability by minimizing the Kullback-Leibler distance [1] of the pdf of the within-source variability to that of the between-source variability given within-source variability mean and variance. It thus finds a conservative estimate of the pdf of within-source variability. Working out this optimization problem results in an log likelihood ration that is a second order polynomial of a given score value. We apply this approach of likelihood ratio computation in the area of face recognition. An existing commercial face recognition system [2] is used to obtain scores for the sets of within-source variability and between-source variability from a set of image data taken from SCFace database [3] . It contains images taken in uncontrolled indoor environment using five video surveillance cameras of various qualities. For each subject, there are also mug shots taken in same conditions as would be expected for any law enforcement or national security use. We explore the feasibility of using an existing biometric face recognition system in forensic application by discussing some specific cases in forensic framework.
doi:10.1007/s11042-009-0417-2 fatcat:h3435jnhszaznkizipslaeq2wi

Image Compression in Face Recognition - a Literature Survey [chapter]

Kresimir Delac, Sonja Grgic, Mislav Grgic
2008 Recent Advances in Face Recognition  
doi:10.5772/6389 fatcat:gdhfw6vngvgrlgp2hzqqzwvoaa

Modified SPIHT algorithm for wavelet packet image coding

Nikola Sprljan, Sonja Grgic, Mislav Grgic
2005 Real-time imaging  
This paper introduces a new implementation of wavelet packet decomposition which is combined with SPIHT (Set Partitioning in Hierarchical Trees) compression scheme. We provide the analysis of the problems arising from the application of zerotree quantisation based algorithms (such as SPIHT) to wavelet packet transform coefficients. We established the generalized parent-child relationships for wavelet packets, providing complete tree structures for SPIHT. The proposed algorithm can be used for
more » ... th wavelet dyadic and Wavelet Packet decomposition (WP-SPIHT). An extensive evaluation of the algorithm was performed and it has been shown that WP-SPIHT significantly outperforms base-line SPIHT coder for texture images. For these images the suboptimal WP cost-function enables good enough energy compaction that is efficiently exploited by the WP-SPIHT. r
doi:10.1016/j.rti.2005.06.009 fatcat:bsuqmypdczgvvjnkuocnxgfrrm

Effects of JPEG and JPEG2000 Compression on Face Recognition [chapter]

Kresimir Delac, Mislav Grgic, Sonja Grgic
2005 Lecture Notes in Computer Science  
In this paper we analyse the effects that JPEG and JPEG2000 compression have on subspace appearance-based face recognition algorithms. This is the first comprehensive study of standard JPEG2000 compression effects on face recognition, as well as an extension of existing experiments for JPEG compression. A wide range of bitrates (compression ratios) was used on probe images and results are reported for 12 different subspace face recognition algorithms. Effects of image compression on recognition
more » ... performance are of interest in applications where image storage space and image transmission time are of critical importance. It will be shown that not only that compression does not deteriorate performance but it, in some cases, even improves it slightly. Some unexpected effects will be presented (like the ability of JPEG2000 to capture the information essential for recognizing changes caused by images taken later in time) and lines of further research suggested.
doi:10.1007/11552499_16 fatcat:fxswyjqpmbchpmjeusgpimg3fe

Face recognition in JPEG and JPEG2000 compressed domain

Kresimir Delac, Mislav Grgic, Sonja Grgic
2009 Image and Vision Computing  
In this paper we investigate the potential of performing face recognition in JPEG and JPEG2000 compressed domain. This is achieved by avoiding full decompression and using transform coefficients as input to face recognition algorithms. We propose a new comparison methodology and by employing it show that face recognition can efficiently be implemented directly into compressed domain. In the first part of our experiment we use all the available transform coefficients and show that recognition
more » ... es are comparable and in some cases even higher than recognition rates obtained by using pixels from uncompressed images (standard face recognition approach). In the second part, we propose an effective coefficient preselection method (applicable both in JPEG and JPEG2000 compressed domain). Our results show that by using the proposed method, recognition rates can be significantly improved while additionally reducing computational time. Finally, we propose what a hypothetical compressed domain face recognition system should look like.
doi:10.1016/j.imavis.2008.10.007 fatcat:fg2n7yuk4fc3bmbffk4zpzif4m

Comparison of HDTV formats using objective video quality measures

Emil Dumic, Sonja Grgic, Mislav Grgic
2010 Multimedia tools and applications  
Black bars denote coefficients that are calculated before nonlinear regression; gray bars denote coefficients that are calculated after nonlinear regression Mislav Grgic received B.Sc., M.Sc. and Ph.D  ...  Grgic is a senior member of IEEE.  ... 
doi:10.1007/s11042-009-0441-2 fatcat:cmimev45ybcvzgx3abldq4ltri

Fuzzy Logic Power Control in Cognitive Radio

Zeljko Tabakovic, Sonja Grgic, Mislav Grgic
2009 2009 16th International Conference on Systems, Signals and Image Processing  
Opportunistic radio spectrum access has the possibility to improve spectrum utilization needed for next generation mobile networks. The main challenge to opportunistic radio spectrum access lies in finding balance in conflicting goals of satisfying performance requirements while minimizing interference. In this paper we propose new strategy for fuzzy logic transmit power control which enables cognitive secondary user to achieve its required transmission rate and quality, while minimizing
more » ... rence to the primary users and other concurrent secondary users. Keywords -cognitive radio; opportunistic radio spectrum access; transmit power control; fuzzy logic systems I.
doi:10.1109/iwssip.2009.5367794 fatcat:5pxfrnquffdglk633i4todal4u

Breast Density Classification Using Multiple Feature Selection

Mario Muštra, Mislav Grgić, Krešimir Delač
2012 Automatika  
Grgić, K. Delač Classifier Feature selection method, (Wrapper+...)  ...  Grgić, K. Delač a feature vector of 288 elements. Features extracted from the GLCMs are shown in appendix.  ... 
doi:10.7305/automatika.55-1.281 fatcat:idg27nr2kzdrlhxczhxicwypam

Simple method for intermodulation products counting in multicarrier systems

Tomislav Kos, Sonja Grgic, Mislav Grgic
2008 AEU - International Journal of Electronics and Communications  
This paper presents a novel algorithm for intermodulation products counting in multicarrier systems. Intermodulation products are caused by the nonlinearity of the amplifiers' transfer characteristic. Along the transmission network, broadband amplifiers are needed to boost up the signal level and compensate the signal attenuation. When the number of carriers increases, the number of intermodulation products also increases extremely fast. In our approach, selective counting procedure by grouping
more » ... intermodulation products was introduced. The presented solution shows considerable reduction in computational effort in counting the number of intermodulation products in the individual channel, especially if the number of products is very large.
doi:10.1016/j.aeue.2007.02.008 fatcat:girhslg7pvaofegk5l4b3g6gzm

Breast Density Classification Using Multiple Feature Selection

Mario Muštra, Mislav Grgić, Krešimir Delač
2012 Automatika  
Grgić, K.  ...  Mislav Grgić received his BSc, MSc, and PhD in electrical engineering from University of Zagreb, Faculty of Electrical Engineering and Computing (FER), Zagreb, Croatia, in 1997, 1998, and 2000, respectively  ... 
doi:10.7305/automatika.53-4.281 fatcat:aqpdn3ssjbbglcjiulp2omkqy4

Filtering for More Accurate Dense Tissue Segmentation in Digitized Mammograms [article]

Mario Muštra, Mislav Grgić
2013 arXiv   pre-print
Breast tissue segmentation into dense and fat tissue is important for determining the breast density in mammograms. Knowing the breast density is important both in diagnostic and computer-aided detection applications. There are many different ways to express the density of a breast and good quality segmentation should provide the possibility to perform accurate classification no matter which classification rule is being used. Knowing the right breast density and having the knowledge of changes
more » ... n the breast density could give a hint of a process which started to happen within a patient. Mammograms generally suffer from a problem of different tissue overlapping which results in the possibility of inaccurate detection of tissue types. Fibroglandular tissue presents rather high attenuation of X-rays and is visible as brighter in the resulting image but overlapping fibrous tissue and blood vessels could easily be replaced with fibroglandular tissue in automatic segmentation algorithms. Small blood vessels and microcalcifications are also shown as bright objects with similar intensities as dense tissue but do have some properties which makes possible to suppress them from the final results. In this paper we try to divide dense and fat tissue by suppressing the scattered structures which do not represent glandular or dense tissue in order to divide mammograms more accurately in the two major tissue types. For suppressing blood vessels and microcalcifications we have used Gabor filters of different size and orientation and a combination of morphological operations on filtered image with enhanced contrast.
arXiv:1310.0305v1 fatcat:2gyyftl7tzb7bixckwkg4ilium

Independent comparative study of PCA, ICA, and LDA on the FERET data set

Kresimir Delac, Mislav Grgic, Sonja Grgic
2005 International journal of imaging systems and technology (Print)  
Face recognition is one of the most successful applications of image analysis and understanding and has gained much attention in recent years. Various algorithms were proposed and research groups across the world reported different and often contradictory results when comparing them. The aim of this paper is to present an independent, comparative study of three most popular appearance-based face recognition projection methods (PCA, ICA, and LDA) in completely equal working conditions regarding
more » ... reprocessing and algorithm implementation. We are motivated by the lack of direct and detailed independent comparisons of all possible algorithm implementations (e.g., all projection-metric combinations) in available literature. For consistency with other studies, FERET data set is used with its standard tests (gallery and probe sets). Our results show that no particular projection-metric combination is the best across all standard FERET tests and the choice of appropriate projection-metric combination can only be made for a specific task. Our results are compared to other available studies and some discrepancies are pointed out. As an additional contribution, we also introduce our new idea of hypothesis testing across all ranks when comparing performance results.
doi:10.1002/ima.20059 fatcat:5yimndh4wrazfaaamucgv45nvi

Robust automatic breast and pectoral muscle segmentation from scanned mammograms

Mario Mustra, Mislav Grgic
2013 Signal Processing  
Grgic, Robust automatic breast and pectoral muscle segmentation from scanned mammograms, Signal Processing (2012), http://dx.  ...  Grgic / Signal Processing ] (]]]]) ]]]-]]]  ...  Grgic, Robust automatic breast and pectoral muscle segmentation from scanned mammograms, Signal Processing (2012), http://dx.doi.org/10.1016/j.sigpro.2012.07.026 x-axis of almost vertical orientation  ... 
doi:10.1016/j.sigpro.2012.07.026 fatcat:p754ugnsvvc2jptfqalng5arry
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