Ronald Vargas - Academia.edu (original) (raw)
Papers by Ronald Vargas
2018 International Conference on Signals and Electronic Systems (ICSES), 2018
The paper reports the results on virtual navigation in a sports hall. The video data is gathered ... more The paper reports the results on virtual navigation in a sports hall. The video data is gathered and processed off-line thus producing the multiview plus depth representation of a scene. This representation is an input to the rendering server. Even a typical PC computer is able to serve a number of users that freely and independently navigate in real-time and watch virtual video. The users are able to navigate in the scene changing the virtual viewpoint and virtual view direction. The service is provided through a webpage, so a viewer does not need to install any software on smartphone, tablet or notebook. The paper discusses the technical solutions together with the rationale for their choice.
Measurement Automation Monitoring, 2015
This article shows the concept of implementation of the remote programmable FPGA module on the se... more This article shows the concept of implementation of the remote programmable FPGA module on the selected hardware platforms. It presents the possibilities of programmable matrix configurations and different ways of data transmission through an appropriate interface. Results and measurements of operating times for the solution proposed by authors are presented.
Measurement Automation Monitoring, 2015
The paper presents a sound synthesizer dedicated to parametric sound compression, but also able t... more The paper presents a sound synthesizer dedicated to parametric sound compression, but also able to generate any signal in the audible band. The synthesizer is realized on an FPGA platform, and it uses additive sound synthesis. The synthesizer is characterized by a high quality, faithful reproduction of sound and low power consumption.
2017 International Conference on Systems, Signals and Image Processing (IWSSIP), 2017
This paper presents the temporal enhancement of the graph-based depth estimation method, designed... more This paper presents the temporal enhancement of the graph-based depth estimation method, designed for multiview systems with arbitrarily located cameras. The primary goal of the proposed enhancement is to increase the quality of estimated depth maps and simultaneously decrease the time of estimation. The method consists of two stages: the temporal enhancement of segmentation required in used depth estimation method, and the exploitation of depth information from the previous frame in the energy function minimization. Performed experiments show that for all tested sequences the quality of estimated depth maps was increased. Even if only one cycle of optimization is used in proposed method, the quality is higher than for unmodified method, apart from number of cycles. Therefore, use of proposed enhancement allows estimating depth of better quality even with 40% reduction of estimation time.
We develop and analyze a new family of nonaccelerated and accelerated loopless variance-reduced m... more We develop and analyze a new family of nonaccelerated and accelerated loopless variance-reduced methods for finite sum optimization problems. Our convergence analysis relies on a novel expected smoothness condition which upper bounds the variance of the stochastic gradient estimation by a constant times a distancelike function. This allows us to handle with ease arbitrary sampling schemes as well as the nonconvex case. We perform an in-depth estimation of these expected smoothness parameters and propose new importance samplings which allow linear speedup when the expected minibatch size is in a certain range. Furthermore, a connection between these expected smoothness parameters and expected separable overapproximation (ESO) is established, which allows us to exploit data sparsity as well. Our results recover as special cases the recently proposed loopless SVRG and loopless Katyusha.
Delays in the delivery of immersive video to Head Mounted Devices (HMDs) are considered in the pa... more Delays in the delivery of immersive video to Head Mounted Devices (HMDs) are considered in the paper. The goal of this paper is to analyze the impact of video streaming latency on user experience with HMDs. The paper reports the results of the subjective quality assessment as a function of delay. The possible practical solutions are identified and, on this base, an experimental model of the considered systems is proposed. In order to properly test the influence of the streaming delay on the quality, the extensive subjective tests have been performed. Interesting conclusions have been drawn, showing that human acceptance of delay of translation of virtual point of viewing is much stronger than for delay of rotation of virtual viewing direction in immersive video. Finally, the influence of such observations on the system architectures is concluded.
In this paper, a modification of the graph-based depth estimation is presented. The purpose of pr... more In this paper, a modification of the graph-based depth estimation is presented. The purpose of proposed modification is to increase the quality of estimated depth maps, reduce the time of the estimation, and increase the temporal consistency of depth maps. The modification is based on the image segmentation using superpixels, therefore in the first step of the proposed modification a segmentation of previous frames is used in the currently processed frame in order to reduce the overall time of the depth estimation. In the next step, a depth map from the previous frame is used in the depth map optimization as the initial values of a depth map estimated for the current frame. It results in the better representation of silhouettes of objects in depth maps and in the reduced computational complexity of the depth estimation process. In order to evaluate the performance of the proposed modification the authors performed the experiment for a set of multiview test sequences that varied in t...
2017 IEEE International Conference on Image Processing (ICIP), 2017
The demonstration is aimed at presenting a simple freeviewpoint television system that is under d... more The demonstration is aimed at presenting a simple freeviewpoint television system that is under development at
IEEE Transactions on Multimedia, 2018
2016 International Conference on Systems, Signals and Image Processing (IWSSIP), 2016
The paper considers the influence of a lossy compression of multiview video on the quality of est... more The paper considers the influence of a lossy compression of multiview video on the quality of estimated depth maps. We have encoded a set of views with commonly known compression techniques used in compact IP cameras: HEVC (MPEG H part 2 / H.265), AVC (MPEG 4 part 10 / H.264) and MPEG 2 part 2 / H.262. Basing on the decoded data we have estimated depth maps and rendered a set of the intermediate virtual views. A drop of the quality was studied by comparison of virtual views rendered out of the depth maps estimated from an uncompressed video. The obtained results show that with a reasonable compression rate, lower quality of virtual views is acceptable for real implementable FTV systems.
2016 International Conference on Signals and Electronic Systems (ICSES), 2016
2015 IEEE International Conference on Multimedia & Expo Workshops (ICMEW), 2015
2018 International Conference on Signals and Electronic Systems (ICSES), 2018
The paper reports the results on virtual navigation in a sports hall. The video data is gathered ... more The paper reports the results on virtual navigation in a sports hall. The video data is gathered and processed off-line thus producing the multiview plus depth representation of a scene. This representation is an input to the rendering server. Even a typical PC computer is able to serve a number of users that freely and independently navigate in real-time and watch virtual video. The users are able to navigate in the scene changing the virtual viewpoint and virtual view direction. The service is provided through a webpage, so a viewer does not need to install any software on smartphone, tablet or notebook. The paper discusses the technical solutions together with the rationale for their choice.
Measurement Automation Monitoring, 2015
This article shows the concept of implementation of the remote programmable FPGA module on the se... more This article shows the concept of implementation of the remote programmable FPGA module on the selected hardware platforms. It presents the possibilities of programmable matrix configurations and different ways of data transmission through an appropriate interface. Results and measurements of operating times for the solution proposed by authors are presented.
Measurement Automation Monitoring, 2015
The paper presents a sound synthesizer dedicated to parametric sound compression, but also able t... more The paper presents a sound synthesizer dedicated to parametric sound compression, but also able to generate any signal in the audible band. The synthesizer is realized on an FPGA platform, and it uses additive sound synthesis. The synthesizer is characterized by a high quality, faithful reproduction of sound and low power consumption.
2017 International Conference on Systems, Signals and Image Processing (IWSSIP), 2017
This paper presents the temporal enhancement of the graph-based depth estimation method, designed... more This paper presents the temporal enhancement of the graph-based depth estimation method, designed for multiview systems with arbitrarily located cameras. The primary goal of the proposed enhancement is to increase the quality of estimated depth maps and simultaneously decrease the time of estimation. The method consists of two stages: the temporal enhancement of segmentation required in used depth estimation method, and the exploitation of depth information from the previous frame in the energy function minimization. Performed experiments show that for all tested sequences the quality of estimated depth maps was increased. Even if only one cycle of optimization is used in proposed method, the quality is higher than for unmodified method, apart from number of cycles. Therefore, use of proposed enhancement allows estimating depth of better quality even with 40% reduction of estimation time.
We develop and analyze a new family of nonaccelerated and accelerated loopless variance-reduced m... more We develop and analyze a new family of nonaccelerated and accelerated loopless variance-reduced methods for finite sum optimization problems. Our convergence analysis relies on a novel expected smoothness condition which upper bounds the variance of the stochastic gradient estimation by a constant times a distancelike function. This allows us to handle with ease arbitrary sampling schemes as well as the nonconvex case. We perform an in-depth estimation of these expected smoothness parameters and propose new importance samplings which allow linear speedup when the expected minibatch size is in a certain range. Furthermore, a connection between these expected smoothness parameters and expected separable overapproximation (ESO) is established, which allows us to exploit data sparsity as well. Our results recover as special cases the recently proposed loopless SVRG and loopless Katyusha.
Delays in the delivery of immersive video to Head Mounted Devices (HMDs) are considered in the pa... more Delays in the delivery of immersive video to Head Mounted Devices (HMDs) are considered in the paper. The goal of this paper is to analyze the impact of video streaming latency on user experience with HMDs. The paper reports the results of the subjective quality assessment as a function of delay. The possible practical solutions are identified and, on this base, an experimental model of the considered systems is proposed. In order to properly test the influence of the streaming delay on the quality, the extensive subjective tests have been performed. Interesting conclusions have been drawn, showing that human acceptance of delay of translation of virtual point of viewing is much stronger than for delay of rotation of virtual viewing direction in immersive video. Finally, the influence of such observations on the system architectures is concluded.
In this paper, a modification of the graph-based depth estimation is presented. The purpose of pr... more In this paper, a modification of the graph-based depth estimation is presented. The purpose of proposed modification is to increase the quality of estimated depth maps, reduce the time of the estimation, and increase the temporal consistency of depth maps. The modification is based on the image segmentation using superpixels, therefore in the first step of the proposed modification a segmentation of previous frames is used in the currently processed frame in order to reduce the overall time of the depth estimation. In the next step, a depth map from the previous frame is used in the depth map optimization as the initial values of a depth map estimated for the current frame. It results in the better representation of silhouettes of objects in depth maps and in the reduced computational complexity of the depth estimation process. In order to evaluate the performance of the proposed modification the authors performed the experiment for a set of multiview test sequences that varied in t...
2017 IEEE International Conference on Image Processing (ICIP), 2017
The demonstration is aimed at presenting a simple freeviewpoint television system that is under d... more The demonstration is aimed at presenting a simple freeviewpoint television system that is under development at
IEEE Transactions on Multimedia, 2018
2016 International Conference on Systems, Signals and Image Processing (IWSSIP), 2016
The paper considers the influence of a lossy compression of multiview video on the quality of est... more The paper considers the influence of a lossy compression of multiview video on the quality of estimated depth maps. We have encoded a set of views with commonly known compression techniques used in compact IP cameras: HEVC (MPEG H part 2 / H.265), AVC (MPEG 4 part 10 / H.264) and MPEG 2 part 2 / H.262. Basing on the decoded data we have estimated depth maps and rendered a set of the intermediate virtual views. A drop of the quality was studied by comparison of virtual views rendered out of the depth maps estimated from an uncompressed video. The obtained results show that with a reasonable compression rate, lower quality of virtual views is acceptable for real implementable FTV systems.
2016 International Conference on Signals and Electronic Systems (ICSES), 2016
2015 IEEE International Conference on Multimedia & Expo Workshops (ICMEW), 2015