Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Denis Vranješ is active.

Publication


Featured researches published by Denis Vranješ.


IEEE Transactions on Vehicular Technology | 2018

Permutation Index DCSK Modulation Technique for Secure Multiuser High-Data-Rate Communication Systems

Marijan Herceg; Georges Kaddoum; Denis Vranješ; Ebrahim Soujeri

A new noncoherent scheme called Permutation Index Differential Chaos Shift Keying (PI-DCSK) modulation is proposed in this paper. This original design aims to enhance data security, energy and spectral efficiencies, compared to its rivals. In the proposed PI-DCSK scheme, each data frame is divided into two time slots in which the reference chaotic signal is sent in the first time slot and a permuted replica of the reference signal multiplied by the modulating bit is sent in the second time slot. In particular, the bit stream is divided at the transmitter into blocks of


International Journal of Electronics | 2019

Chaos-Based transmitted-reference ultra-wideband communications

Marijan Herceg; Denis Vranješ; Ratko Grbić; Josip Job

n+1


Multimedia Tools and Applications | 2018

Foveation-based content adaptive root mean squared error for video quality assessment

Mario Vranješ; Snježana Rimac-Drlje; Denis Vranješ

bits, where


international conference on systems signals and image processing | 2016

Fast frame-rate up-conversion method for video enhancement

Snježana Rimac-Drlje; Denis Vranješ

n


international symposium elmar | 2014

Influence of spatial and temporal activity of upscaled video on its perceived quality

Mario Vranješ; Denis Vranješ; Snjezana Rimac-Drlje

mapped bits are used to select one of the predefined reference sequence permutations, while a single modulated bit is spread by the permuted reference signal just mentioned. At the receiver side, the reference signal is recovered first, then all permuted versions of it are correlated with the data-bearing signal. The index of the correlator output with maximum magnitude will estimate the mapped bits, while the output content of the corresponding correlator is compared to a zero threshold to recover the modulated bit. Moreover, a new multiple access method based on the proposed scheme is described and analysed. Analytical expressions for the error performance in single-user and multiuser environments are derived for additive white Gaussian noiseand multipath Rayleigh fading channels, respectively. Furthermore, the performance of the proposed PI-DCSK system is analysed and compared with other noncoherent chaotic modulation schemes and is found to be promising.


international symposium elmar | 2012

Comparison of objective quality assessment methods for scalable video coding

Denis Vranješ; Drago Zagar; Ognjen Nemčić

ABSTRACT Transmitted-reference (TR) ultra-wideband (UWB) communication systems have gained increasing popularity for the usage in the low data rate application, due to its non-coherent receiver structure. In conventional TR system, non-coherency at the receiver is achieved by sending reference pulses prior to the data-bearing pulses. Then, at the receiver side, reference pulses are used as template signals for correlation with data-bearing pulses. Therefore, the orthogonality between reference and data pulses is obtained in time division multiple access (TDMA) fashion. However, the implementation of a wideband delay line is very difficult in the current low power integrated circuits. In this paper, a TR method called Chaos-Based TR (CB-TR) is proposed. In the proposed method, chaotic sequences are used to separate the reference and data pulses. Such approach exploits the benefits of chaotic signals, such as non-periodicity, easy-to-generate, impulse-like autocorrelation value and low cross-correlation value. Furthermore, in order to decrease the influence of some negative properties of conventional chaotic maps, a modified chaotic generator (MCS) is proposed. Simulation results over the IEEE 802.15.4a channel model show comparable bit error rate performance to other TR methods.


international symposium elmar | 2013

Spatial upscaling of scalable coded video for mobile applications

Denis Vranješ; Mario Vranješ; Snjezana Rimac-Drlje

When the video is compressed and transmitted over heterogeneous networks, it is necessary to ensure the satisfying quality for the end user. Since human observers are the end users of video applications, it is very important that the human visual system (HVS) characteristics are taken into account during the video quality evaluation. This paper deals with video quality assessment (VQA) based on HVS characteristics and proposes a novel full-reference (FR) VQA metric called the Foveation-based content Adaptive Root Mean Squared Error (FARMSE). FARMSE uses several HVS characteristics that significantly influence perception of distortions in a video. Primarily these are foveated vision, reduction of the spatial acuity due to motions as well as spatial masking. Foveated vision is related to variable resolution of HVS across the viewing field, where the highest resolution is at the point of fixation. The point of fixation is projected onto the fovea – the area of retina with the highest density of photoreceptors. The part of image that falls on fovea is perceived by the highest acuity, whereas the spatial acuity decreases as the distance of the image part from the fovea increases. Spatial acuity further decreases if eyes cannot track moving objects. Both mentioned mechanisms influence contrast sensitivity of the HVS. Contrast sensitivity is frequency dependent and FARMSE uses Haar filters to utilize this dependence. Furthermore, spatial masking is implemented in each frequency channel. The FARMSE performance is compared to this of nine state-of-the-art VQA metrics on two different databases, LIVE and ECVQ. Additionally, the metrics are compared in terms of calculation complexity. The performed experiments show that FARMSE achieves high performance when predicting the quality of videos with different resolutions, degradation types and content types. FARMSE results outperform the results of most of the analyzed metrics, whereas they are comparable to these of the best publicly available metrics, including the well-known MOtion-based Video Integrity Evaluation (MOVIE) index. Besides that, FARMSE calculation complexity is significantly lower than that of the metrics comparable thereto in terms of prediction accuracy.


international symposium elmar | 2012

ECVQ and EVVQ video quality databases

Mario Vranješ; Snježana Rimac-Drlje; Denis Vranješ

In this paper a new frame-rate up-conversion (FRUC) method is presented. To obtain an algorithm with a low level of complexity we used the block matching technique and fast subpixel motion estimation by Taylor series. Frame interpolation is made by combination of forward and backward prediction. Furthermore, for frames with a low temporal activity, the motion estimation is skipped and simple averaging of the previous and following frames makes the frame interpolation. Quality of the interpolated frames is compared according to PSNR results obtained for proposed and two more complex FRUC methods. Proposed method shows comparable results for all tested video sequences except for the sequences with a high level of motion.


Proceedings ELMAR-2011 | 2011

Video content complexity and performance of video transmission over IP and WLAN networks

Denis Vranješ; Mario Vranješ; Snježana Rimac-Drlje

High network resources costs led to the increasingly usage of scalable video coding in video transmission over the network. Prior to displaying on user device, the transmitted video should be spatial and/or temporal upscaled in order to ensure the acceptable perceived quality level. In this work the relationship between the spatio-temporal activity of upscaled sequence and its perceived quality is examined. The experiments are performed for videos presented on PC and on smartphone, while three different activity measures are analyzed. It is shown that the newly-introduced spatio-temporal activity measure, called SITImean, achieves a high level of correlation with subjective quality scores. Therefore it could be used as an indicator of upscaled video quality, replacing the expensive subjective quality evaluation tests.


IEEE Transactions on Circuits and Systems Ii-express Briefs | 2018

Commutation Code Index DCSK Modulation Technique for High-Data-Rate Communication Systems

Marijan Herceg; Denis Vranješ; Georges Kaddoum; Ebrahim Soujeri

Collaboration


Dive into the Denis Vranješ's collaboration.

Top Co-Authors

Avatar

Mario Vranješ

Josip Juraj Strossmayer University of Osijek

View shared research outputs
Top Co-Authors

Avatar

Snježana Rimac-Drlje

Josip Juraj Strossmayer University of Osijek

View shared research outputs
Top Co-Authors

Avatar

Marijan Herceg

Josip Juraj Strossmayer University of Osijek

View shared research outputs
Top Co-Authors

Avatar

Snjezana Rimac-Drlje

Josip Juraj Strossmayer University of Osijek

View shared research outputs
Top Co-Authors

Avatar

Georges Kaddoum

École de technologie supérieure

View shared research outputs
Top Co-Authors

Avatar

Drago Zagar

Josip Juraj Strossmayer University of Osijek

View shared research outputs
Top Co-Authors

Avatar

Josip Job

Josip Juraj Strossmayer University of Osijek

View shared research outputs
Top Co-Authors

Avatar

Ratko Grbić

Josip Juraj Strossmayer University of Osijek

View shared research outputs
Top Co-Authors

Avatar

Tomislav Matić

Josip Juraj Strossmayer University of Osijek

View shared research outputs
Top Co-Authors

Avatar

Ebrahim Soujeri

European University of Lefka

View shared research outputs
Researchain Logo
Decentralizing Knowledge