Ponències/Comunicacions de congressoshttp://hdl.handle.net/2117/35672024-03-29T10:39:07Z2024-03-29T10:39:07ZCoupling camera-tracked humans with a simulated virtual crowdRivalcoba, Jorge IvanDe Gyves, OriamRudomin, IsaacPelechano Gómez, Núriahttp://hdl.handle.net/2117/246682020-07-23T21:05:57Z2014-11-11T10:26:34ZCoupling camera-tracked humans with a simulated virtual crowd
Rivalcoba, Jorge Ivan; De Gyves, Oriam; Rudomin, Isaac; Pelechano Gómez, Núria
Our objective with this paper is to show how we can couple a group of real people and a simulated crowd of virtual humans. We attach group behaviors to the simulated humans to get a plausible reaction to real people. We use a two stage system: in the first stage, a group of people are segmented from a live video, then a human detector algorithm extracts the positions of the people in the video, which are finally used to feed the second stage, the simulation system. The positions obtained by this process allow the second module to render the real humans as avatars in the scene, while the behavior of additional virtual humans is determined by using a simulation based on a social forces model. Developing the method required three specific contributions: a GPU implementation of the codebook algorithm that includes an auxiliary codebook to improve the background subtraction against illumination changes; the use of semantic local binary patterns as a human descriptor; the parallelization of a social forces model, in which we solve a case of agents merging with each other. The experimental results show how a large virtual crowd reacts to over a dozen humans in a real environment.
2014-11-11T10:26:34ZRivalcoba, Jorge IvanDe Gyves, OriamRudomin, IsaacPelechano Gómez, NúriaOur objective with this paper is to show how we can couple a group of real people and a simulated crowd of virtual humans. We attach group behaviors to the simulated humans to get a plausible reaction to real people. We use a two stage system: in the first stage, a group of people are segmented from a live video, then a human detector algorithm extracts the positions of the people in the video, which are finally used to feed the second stage, the simulation system. The positions obtained by this process allow the second module to render the real humans as avatars in the scene, while the behavior of additional virtual humans is determined by using a simulation based on a social forces model. Developing the method required three specific contributions: a GPU implementation of the codebook algorithm that includes an auxiliary codebook to improve the background subtraction against illumination changes; the use of semantic local binary patterns as a human descriptor; the parallelization of a social forces model, in which we solve a case of agents merging with each other. The experimental results show how a large virtual crowd reacts to over a dozen humans in a real environment.CAVAST: The crowd animation, visualization, and simulation testbedBeacco Porres, AlejandroPelechano Gómez, Núriahttp://hdl.handle.net/2117/244802023-01-08T09:25:04Z2014-10-25T18:45:39ZCAVAST: The crowd animation, visualization, and simulation testbed
Beacco Porres, Alejandro; Pelechano Gómez, Núria
Simulation, animation and rendering of crowds has become an important part of real-time applications such as videogames. Virtual environments achieve higher realism when being populated by virtual crowds as opposed to appearing uninhabited. There has been a large amount of research on simulation, animation and rendering of crowds, but in most cases they seem to be treated separately as if the limitations in one area did not affect the others. At the end of the day the goal is to populate environments with as many characters as possible in real
time, and it is of little use if one can for instance render thousands of characters in real time, but you cannot move more than a hundred due to a simulation bottleneck. The goal of our work is to provide a framework that lets the
researcher focus on each of these topics at a time (simulation, animation, or rendering) and be able to explore and push the boundaries on one topic without being strongly limited by the other related issues. This paper presents therefore a new prototyping testbed for crowds that lets the researcher focus on one of these areas of research at a time without loosing sight of the others. We offer default representations, animation and simulation controllers for real time crowd simulation, that can easily be replaced or extended. Fully configurable level-of-detail for both rendering and simulation is also available
2014-10-25T18:45:39ZBeacco Porres, AlejandroPelechano Gómez, NúriaSimulation, animation and rendering of crowds has become an important part of real-time applications such as videogames. Virtual environments achieve higher realism when being populated by virtual crowds as opposed to appearing uninhabited. There has been a large amount of research on simulation, animation and rendering of crowds, but in most cases they seem to be treated separately as if the limitations in one area did not affect the others. At the end of the day the goal is to populate environments with as many characters as possible in real
time, and it is of little use if one can for instance render thousands of characters in real time, but you cannot move more than a hundred due to a simulation bottleneck. The goal of our work is to provide a framework that lets the
researcher focus on each of these topics at a time (simulation, animation, or rendering) and be able to explore and push the boundaries on one topic without being strongly limited by the other related issues. This paper presents therefore a new prototyping testbed for crowds that lets the researcher focus on one of these areas of research at a time without loosing sight of the others. We offer default representations, animation and simulation controllers for real time crowd simulation, that can easily be replaced or extended. Fully configurable level-of-detail for both rendering and simulation is also availableNightLighting: a nocturnal urban illumination approachMuñoz Pandiella, ImanolAndújar Gran, Carlos AntonioPatow, Gustavo Arielhttp://hdl.handle.net/2117/233392023-09-10T08:36:39Z2014-07-01T07:53:59ZNightLighting: a nocturnal urban illumination approach
Muñoz Pandiella, Imanol; Andújar Gran, Carlos Antonio; Patow, Gustavo Ariel
Real time rendering of cities with realistic global illumination is still an open problem. In this paper we propose a two-step algorithm to simulate the nocturnal illumination of a city. The first step computes an approximate aerial solution using simple textured quads for each street light. The second step uses photon mapping to locally compute the global illumination coming from light sources close to the viewer. Then, we transfer the local, highquality solution to the low resolution buffers used for aerial views, refining it with accurate information from the local simulation. Our approach achieves real time frame rates in commodity hardware.
2014-07-01T07:53:59ZMuñoz Pandiella, ImanolAndújar Gran, Carlos AntonioPatow, Gustavo ArielReal time rendering of cities with realistic global illumination is still an open problem. In this paper we propose a two-step algorithm to simulate the nocturnal illumination of a city. The first step computes an approximate aerial solution using simple textured quads for each street light. The second step uses photon mapping to locally compute the global illumination coming from light sources close to the viewer. Then, we transfer the local, highquality solution to the low resolution buffers used for aerial views, refining it with accurate information from the local simulation. Our approach achieves real time frame rates in commodity hardware.A generalized exact arbitrary clearance technique for navigation meshesOliva Martínez, RamonPelechano Gómez, Núriahttp://hdl.handle.net/2117/232312020-07-23T22:01:59Z2014-06-16T11:46:18ZA generalized exact arbitrary clearance technique for navigation meshes
Oliva Martínez, Ramon; Pelechano Gómez, Núria
There are two frequent artifacts in crowd simulation, the first one appears when all agents attempt to traverse the navigation mesh sharing the same way point over portals, increasing the probability of collision against other agents and lining up towards portals; the second one is caused by way points being assigned at locations where clearance is not guaranteed which causes the agents to walk too close to the static geometry, slide along walls or even get stuck. In this work we propose a novel method for dynamically calculating way points based on current trajectory, destination, and clearance while using the full length of the portal, thus guaranteeing
that agents in a crowd will have different way points assigned. To guarantee collision free paths we propose two novel techniques: the first one provides the computation of paths with clearance for cells of any shape (even with concavities) and the second one presents a new method for calculating portals with clearance, so that the dynamically assigned way points will always guarantee collision free paths. We evaluate our results with a variety of scenarios, and
compare our results against traditional way points at the center of portals to show that our technique offers a better use of the space by the agents, as well as a reduction in the number of collisions.
2014-06-16T11:46:18ZOliva Martínez, RamonPelechano Gómez, NúriaThere are two frequent artifacts in crowd simulation, the first one appears when all agents attempt to traverse the navigation mesh sharing the same way point over portals, increasing the probability of collision against other agents and lining up towards portals; the second one is caused by way points being assigned at locations where clearance is not guaranteed which causes the agents to walk too close to the static geometry, slide along walls or even get stuck. In this work we propose a novel method for dynamically calculating way points based on current trajectory, destination, and clearance while using the full length of the portal, thus guaranteeing
that agents in a crowd will have different way points assigned. To guarantee collision free paths we propose two novel techniques: the first one provides the computation of paths with clearance for cells of any shape (even with concavities) and the second one presents a new method for calculating portals with clearance, so that the dynamically assigned way points will always guarantee collision free paths. We evaluate our results with a variety of scenarios, and
compare our results against traditional way points at the center of portals to show that our technique offers a better use of the space by the agents, as well as a reduction in the number of collisions.Introductory graphics for very diverse audiencesFairén González, MartaPelechano Gómez, Núriahttp://hdl.handle.net/2117/231912020-07-23T21:49:48Z2014-06-10T08:15:07ZIntroductory graphics for very diverse audiences
Fairén González, Marta; Pelechano Gómez, Núria
This paper presents our first experience teaching WebGL in a master’s degree for a class of students with very different backgrounds. The main challenge was to prepare a course that would be engaging for students with computer graphics experience, and yet interesting and non-frustrating for those students unfamiliar with OpenGL.
In this paper we explain how we prepared this course, and the project assignment to achieve our goal. The results achieved by the students show that the course succeeded in keeping different kinds of students engaged and excited with the implementation of their final project.
2014-06-10T08:15:07ZFairén González, MartaPelechano Gómez, NúriaThis paper presents our first experience teaching WebGL in a master’s degree for a class of students with very different backgrounds. The main challenge was to prepare a course that would be engaging for students with computer graphics experience, and yet interesting and non-frustrating for those students unfamiliar with OpenGL.
In this paper we explain how we prepared this course, and the project assignment to achieve our goal. The results achieved by the students show that the course succeeded in keeping different kinds of students engaged and excited with the implementation of their final project.Structural stability of planar bimodal linear systemsFerrer Llop, JosepPeña Carrera, MartaSusín Sánchez, Antoniohttp://hdl.handle.net/2117/217392020-07-23T23:05:47Z2014-02-25T08:57:11ZStructural stability of planar bimodal linear systems
Ferrer Llop, Josep; Peña Carrera, Marta; Susín Sánchez, Antonio
We consider bimodal linear dynamical systems consisting of two linear dynamics acting on each side of a given
hyperplane, assuming continuity along the separating hyperplane. Focusing in the planar case, we describe which of these
systems are structurally stable.
2014-02-25T08:57:11ZFerrer Llop, JosepPeña Carrera, MartaSusín Sánchez, AntonioWe consider bimodal linear dynamical systems consisting of two linear dynamics acting on each side of a given
hyperplane, assuming continuity along the separating hyperplane. Focusing in the planar case, we describe which of these
systems are structurally stable.Multi-domain real-time planning in dynamic environmentsKapadia, MubbasirBeacco Porres, AlejandroGarcia, FranciscoReddy, VivekPelechano Gómez, NúriaBadler, Norman I.http://hdl.handle.net/2117/202772023-01-08T04:40:38Z2013-10-03T10:55:16ZMulti-domain real-time planning in dynamic environments
Kapadia, Mubbasir; Beacco Porres, Alejandro; Garcia, Francisco; Reddy, Vivek; Pelechano Gómez, Núria; Badler, Norman I.
This paper presents a real-time planning framework for multi-character navigation that enables the use of multiple heterogeneous problem domains of differing complexities for navigation in large, complex, dynamic virtual environments. The original navigation problem is decomposed into a set of smaller problems that are distributed across planning tasks working in these different domains. An anytime dynamic planner is used to efficiently compute and repair plans for each of these tasks, while using plans in one domain to focus and accelerate searches in more complex domains. We demonstrate the benefits of our framework by solving many challenging multi-agent scenarios in complex dynamic environments requiring space-time precision and explicit coordination between interacting agents, by accounting for dynamic information at all stages of the decision-making process.
2013-10-03T10:55:16ZKapadia, MubbasirBeacco Porres, AlejandroGarcia, FranciscoReddy, VivekPelechano Gómez, NúriaBadler, Norman I.This paper presents a real-time planning framework for multi-character navigation that enables the use of multiple heterogeneous problem domains of differing complexities for navigation in large, complex, dynamic virtual environments. The original navigation problem is decomposed into a set of smaller problems that are distributed across planning tasks working in these different domains. An anytime dynamic planner is used to efficiently compute and repair plans for each of these tasks, while using plans in one domain to focus and accelerate searches in more complex domains. We demonstrate the benefits of our framework by solving many challenging multi-agent scenarios in complex dynamic environments requiring space-time precision and explicit coordination between interacting agents, by accounting for dynamic information at all stages of the decision-making process.Full high-dynamic range images for dynamic scenesRamírez Orozco, RaisselMartín, IgnacioLoscos, CélineVázquez Alcocer, Pere Pauhttp://hdl.handle.net/2117/193682020-07-23T21:30:47Z2013-05-22T08:40:29ZFull high-dynamic range images for dynamic scenes
Ramírez Orozco, Raissel; Martín, Ignacio; Loscos, Céline; Vázquez Alcocer, Pere Pau
The limited dynamic range of digital images can be extended by composing photographs of the same scene taken with the same camera at the same view point at di erent exposure times. This is a standard procedure for static scenes but a challenging task for dynamic ones. Several methods have been presented but few recover high dynamic range within moving areas. We present a method to recover full high dynamic range (HDR) images
from dynamic scenes, even in moving regions. Our method has 3 steps. Firstly, areas a ected by motion are detected to generate a ghost mask. Secondly, we register dynamic objects over a reference image (the best exposed image in the input sequence). Thirdly, we combine the registered input photographs to recover HDR values in a whole image using a weighted average function. Once matching is found, the assembling step guarantees that all aligned pixels will contribute to the nal result, including dynamic content. Tests were made on more than
20 sets of sequences, with moving cars or pedestrians and di erent background. Our results show that Image Mapping Function approach detects best motion regions while Normalized Cross Correlation o ers the best deal speed-accuracy for image registration. Results from our method o ers better result when moving object are roughly rigid and their movement is mostly rigid. The nal composition is an HDR image with no ghosting and all dynamic content present in HDR values.
2013-05-22T08:40:29ZRamírez Orozco, RaisselMartín, IgnacioLoscos, CélineVázquez Alcocer, Pere PauThe limited dynamic range of digital images can be extended by composing photographs of the same scene taken with the same camera at the same view point at di erent exposure times. This is a standard procedure for static scenes but a challenging task for dynamic ones. Several methods have been presented but few recover high dynamic range within moving areas. We present a method to recover full high dynamic range (HDR) images
from dynamic scenes, even in moving regions. Our method has 3 steps. Firstly, areas a ected by motion are detected to generate a ghost mask. Secondly, we register dynamic objects over a reference image (the best exposed image in the input sequence). Thirdly, we combine the registered input photographs to recover HDR values in a whole image using a weighted average function. Once matching is found, the assembling step guarantees that all aligned pixels will contribute to the nal result, including dynamic content. Tests were made on more than
20 sets of sequences, with moving cars or pedestrians and di erent background. Our results show that Image Mapping Function approach detects best motion regions while Normalized Cross Correlation o ers the best deal speed-accuracy for image registration. Results from our method o ers better result when moving object are roughly rigid and their movement is mostly rigid. The nal composition is an HDR image with no ghosting and all dynamic content present in HDR values.Accurate multi-modal image registration using compressionVázquez Alcocer, Pere PauMarco Gómez, Jordihttp://hdl.handle.net/2117/180172020-07-23T22:48:45Z2013-02-28T11:31:21ZAccurate multi-modal image registration using compression
Vázquez Alcocer, Pere Pau; Marco Gómez, Jordi
Image registration is an important task in medicine, especially when images have been acquired by different scanner/sensor types, since they provide information on different body structures (bones, muscles, vessels...). Several techniques have been proposed in the past, and among those, Normalized Mutual Information has been proven as successful in many cases. Normalized Compression Distance has been proposed as a simple yet effective technique for image registration. It is especially suitable for the case of CT-MRI registration. However, other image modalities such as PET pose some problems and do not achieve accurate registration. In this paper we analyse and propose a valid approach for image registration using compression that works properly for different combinations of CT, MRI and PET images.
2013-02-28T11:31:21ZVázquez Alcocer, Pere PauMarco Gómez, JordiImage registration is an important task in medicine, especially when images have been acquired by different scanner/sensor types, since they provide information on different body structures (bones, muscles, vessels...). Several techniques have been proposed in the past, and among those, Normalized Mutual Information has been proven as successful in many cases. Normalized Compression Distance has been proposed as a simple yet effective technique for image registration. It is especially suitable for the case of CT-MRI registration. However, other image modalities such as PET pose some problems and do not achieve accurate registration. In this paper we analyse and propose a valid approach for image registration using compression that works properly for different combinations of CT, MRI and PET images.Biomechanical validation of upper-body and lower-body joint movements of kinect motion capture data for rehabilitation treatmentsFernández-Baena, AdsoSusín Sánchez, AntonioLligadas, Xavierhttp://hdl.handle.net/2117/171172020-07-23T20:23:21Z2012-12-12T11:23:43ZBiomechanical validation of upper-body and lower-body joint movements of kinect motion capture data for rehabilitation treatments
Fernández-Baena, Adso; Susín Sánchez, Antonio; Lligadas, Xavier
ew and powerful hardware like Kinect introduces
the possibility of changing biomechanics paradigm,
usually based on expensive and complex equipment. Kinect is
a markerless and cheap technology recently introduced from
videogame industry. In this work we conduct a comparison
study of the precision in the computation of joint angles
between Kinect and an optical motion capture professional
system. We obtain a range of disparity that guaranties enough
precision for most of the clinical rehabilitation treatments
prescribed nowadays for patients. This way, an easy and cheap
validation of these treatments can be obtained automatically,
ensuring a better quality control process for the patient’s
rehabilitation.
2012-12-12T11:23:43ZFernández-Baena, AdsoSusín Sánchez, AntonioLligadas, Xavierew and powerful hardware like Kinect introduces
the possibility of changing biomechanics paradigm,
usually based on expensive and complex equipment. Kinect is
a markerless and cheap technology recently introduced from
videogame industry. In this work we conduct a comparison
study of the precision in the computation of joint angles
between Kinect and an optical motion capture professional
system. We obtain a range of disparity that guaranties enough
precision for most of the clinical rehabilitation treatments
prescribed nowadays for patients. This way, an easy and cheap
validation of these treatments can be obtained automatically,
ensuring a better quality control process for the patient’s
rehabilitation.