Noelia Hernandez | Universidad de Alcalá (original) (raw)

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Papers by Noelia Hernandez

In this paper we present a technique to build 3D maps of the environment using a 2D laser scanner... more In this paper we present a technique to build 3D maps of the environment using a 2D laser scanner combined with a robot's action model. This paper demonstrates that it is possible to build 3D maps in a cheap way using an angled 2D laser. We introduce a scan matching method to minimize the odometer errors of the robotics platform. Some experimental results and conclusions are presented.

Mapping techniques based on Wireless Range-Only Sensors (WROS) consist of locating the beacons us... more Mapping techniques based on Wireless Range-Only Sensors (WROS) consist of locating the beacons using distance measurements only. In this work we use WROS working at 2.4GHz band (same as WiFi), which has the disadvantage of being affected by a high noise. The goal of this paper is to study a noisy range-only sensor and its application in the development of mapping systems. A particle filter is used in order to map the environment, this technique has been applied successfully with other technologies, like ultra-wide band (UWB), but we demonstrate that even using a much more noisy sensor this technique can be applied correctly.

13th International IEEE Conference on Intelligent Transportation Systems, 2010

This paper presents a nonintrusive approach for monitoring driver drowsiness, based on computer v... more This paper presents a nonintrusive approach for monitoring driver drowsiness, based on computer vision techniques, installed in a realistic driving simulator. An IR stereo camera is placed in from of the driver in order to obtain PERCLOS, the most confident drowsiness parameter [1], in real-time and in a robust and automatic way. Our proposal doesn't need a calibration process and includes three main stages. The first is the pre-processing stage, which includes face and eye detection based on appearance strategy using the Viola and Jones algorithm, and the equalization of the eyes using a Hat transformation. An eye tracking strategy in a sequence of image frames is then carried out. The second stage executes the pupil position extraction and its characterization using integral projection techniques and a Gaussian model. The final stage executes the PERCLOS estimation, depending on the eyes closed rate on duration of time interval and fusing information obtained for each eye in the two images of the stereo camera. For evaluation of the proposed system several experiments have been designed by psychologists and carried out. A preliminary study about the performance of the proposal, based on confusion matrixes, is presented.

Traditionally, WiFi has been used for indoors localization purposes due to its important advantag... more Traditionally, WiFi has been used for indoors localization purposes due to its important advantages. There are WiFi access points in most buildings and measuring WiFi signal is free of charge even for private WiFi networks. Unfortunately, it also has some disadvantages: when extending WiFi-based localization systems to large environments their accuracy decreases. This has been previously solved by manually dividing the environment into zones. In this paper, an automatic partition of the environment is proposed to increase the localization accuracy in large environments. To do so, a hierarchical partition of the environment is performed using K-Means and the Cali´nski-Harabasz Index. Then, different classification techniques have been compared to achieve high localization rates. The new approach is tested in a real environment with more than 200 access points and 133 topological positions, obtaining an overall increase in the accuracy of approximately 10% and reducing the error to th...

2014 Ubiquitous Positioning Indoor Navigation and Location Based Service (UPINLBS), 2014

ABSTRACT Traditionally, WiFi has been used for indoors localization purposes due to its important... more ABSTRACT Traditionally, WiFi has been used for indoors localization purposes due to its important advantages. First, it is already deployed and its coverage is quickly growing. Second, measuring the WiFi signal strength is free of charge for every WiFi network. Unfortunately, it also has some disadvantages: when extending WiFi-based localization systems to large environments with a high number of APs and positions their accuracy decreases. This has been previously solved by manually dividing the environment into sub-regions. In this paper, an automatic division of the environment using different clustering techniques is proposed. Then the final position is computed by classifying in two different levels (first for a zone, then for a position inside it) using a hierarchical approach. The final performance of the system was improved by dividing the environment in zones obtaining an overall increase in the accuracy of approximately 5%. This indicates that by dividing the environment the overall performance can be improved.

ETFA 2009 - 2009 IEEE Conference on Emerging Technologies and Factory Automation, 2009

The goal of this paper is to study some of the most important WiFi signal variations, large and s... more The goal of this paper is to study some of the most important WiFi signal variations, large and small scale variations and how they affect to WiFi localization systems. Moreover, the paper shows how to use Soft Computing techniques to deal with these uncertainties in WiFi localization systems. This work describes how to reduce uncertainty produced by small scale variations in indoor environments using fuzzy techniques. Some experimental results and conclusions are presented.

IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC, 2010

This paper presents a non intrusive approach to obtain driver's face pose estimation based on ste... more This paper presents a non intrusive approach to obtain driver's face pose estimation based on stereo graylevel image processing. Face pose estimation is based on an automatic and incremental 3D model creation and its correct tracking. From this information, gaze focalization in the scene is calculated in order to detect driver distraction. Different distraction activities are inferred in a realistic simulator and a study of the incidence of these distracting activities in the driver's behaviour is carried out. Some experimental results and conclusions are presented.

IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC, 2011

Driving inattention is a major factor to highway crashes. The National Highway Traffic Safety Adm... more Driving inattention is a major factor to highway crashes. The National Highway Traffic Safety Administration (NHTSA) estimates that approximately 25% of police-reported crashes involve some form of driving inattention. Increasing use of in-vehicle information systems (IVISs) such as cell phones or GPS navigation systems has exacerbated the problem by introducing additional sources of distraction. Enabling drivers to benefit from IVIS without diminishing safety is an important challenge. In this paper, an automatic distraction monitoring system based on gaze focalization for the assessment of IVISs induced distraction is presented. Driver's gaze focalization is estimated using a non-intrusive vision-based approach. This system has been tested in a naturalistic simulator with more than 15 hours of driving in different scenarios and conditions and 12 different professional drivers. The purpose of this work is, on the one hand, to assess the detection capacity of the monitoring system and, in the other hand, to study drivers reactions to different IVISs. Gathering this information the optimal IVISs location and the way the indications should be delivered to the drivers can be studied to reduce the interference with their driving.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2012

Mapping techniques based on Wireless Range-Only Sensors (WROS) consist of locating the beacons us... more Mapping techniques based on Wireless Range-Only Sensors (WROS) consist of locating the beacons using distance measurements only. In this work we use WROS working at 2.4GHz band (same as WiFi), which has the disadvantage of being affected by a high noise. The goal of this paper is to study a noisy range-only sensor and its application in the development of mapping systems. A particle filter is used in order to map the environment, this technique has been applied successfully with other technologies, like ultra-wide band (UWB), but we demonstrate that even using a much more noisy sensor this technique can be applied correctly.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2012

In this paper we present a technique to build 3D maps of the environment using a 2D laser scanner... more In this paper we present a technique to build 3D maps of the environment using a 2D laser scanner combined with a robot's action model. This paper demonstrates that it is possible to build 3D maps in a cheap way using an angled 2D laser. We introduce a scan matching method to minimize the odometer errors of the robotics platform. Some experimental results and conclusions are presented.

Advances in Intelligent Systems and Computing, 2014

ABSTRACT This paper presents different techniques to achieve the tasks proposed in the DARPA (Def... more ABSTRACT This paper presents different techniques to achieve the tasks proposed in the DARPA (Defense Advanced Research Projects Agency) VRC (Virtual Robotics Challenge), which entails the recognition of objects, the robot localization and the mapping of the simulated environments in the Challenge. Data acquisition relies on several sensors such as a stereo camera, a 2D laser, an IMU (Inertial Motion Unit) and stress sensors. Using the map and the position of the robot inside it, we propose a safe path planning to navigate through the environment using an Atlas humanoid robot.

2011 IEEE International Symposium on Industrial Electronics, 2011

This paper describes a new approach for improving the estimation of the global position of a vehi... more This paper describes a new approach for improving the estimation of the global position of a vehicle in complex urban environments by means of visual odometry and map fusion. The visual odometry system is based on the compensation of the heterodasticity in the 3D input data using a weighted nonlinear least squares based system. RANdom SAmple Consensus (RANSAC) based on Mahalanobis distance is used for outlier removal. The motion trajectory information is used to keep track of the vehicle position in a digital map during GPS outages. The final goal is the autonomous vehicle outdoor navigation in large-scale environments and the improvement of current vehicle navigation systems based only on standard GPS. This research is oriented to the development of traffic collective systems aiming vehicle-infrastructure cooperation to improve dynamic traffic management. We provide examples of estimated vehicle trajectories and map fusion using the proposed method and discuss the key issues for further improvement.

Advances in Intelligent Systems and Computing, 2014

2014 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE), 2014

In this paper we present a technique to build 3D maps of the environment using a 2D laser scanner... more In this paper we present a technique to build 3D maps of the environment using a 2D laser scanner combined with a robot's action model. This paper demonstrates that it is possible to build 3D maps in a cheap way using an angled 2D laser. We introduce a scan matching method to minimize the odometer errors of the robotics platform. Some experimental results and conclusions are presented.

Mapping techniques based on Wireless Range-Only Sensors (WROS) consist of locating the beacons us... more Mapping techniques based on Wireless Range-Only Sensors (WROS) consist of locating the beacons using distance measurements only. In this work we use WROS working at 2.4GHz band (same as WiFi), which has the disadvantage of being affected by a high noise. The goal of this paper is to study a noisy range-only sensor and its application in the development of mapping systems. A particle filter is used in order to map the environment, this technique has been applied successfully with other technologies, like ultra-wide band (UWB), but we demonstrate that even using a much more noisy sensor this technique can be applied correctly.

13th International IEEE Conference on Intelligent Transportation Systems, 2010

This paper presents a nonintrusive approach for monitoring driver drowsiness, based on computer v... more This paper presents a nonintrusive approach for monitoring driver drowsiness, based on computer vision techniques, installed in a realistic driving simulator. An IR stereo camera is placed in from of the driver in order to obtain PERCLOS, the most confident drowsiness parameter [1], in real-time and in a robust and automatic way. Our proposal doesn't need a calibration process and includes three main stages. The first is the pre-processing stage, which includes face and eye detection based on appearance strategy using the Viola and Jones algorithm, and the equalization of the eyes using a Hat transformation. An eye tracking strategy in a sequence of image frames is then carried out. The second stage executes the pupil position extraction and its characterization using integral projection techniques and a Gaussian model. The final stage executes the PERCLOS estimation, depending on the eyes closed rate on duration of time interval and fusing information obtained for each eye in the two images of the stereo camera. For evaluation of the proposed system several experiments have been designed by psychologists and carried out. A preliminary study about the performance of the proposal, based on confusion matrixes, is presented.

Traditionally, WiFi has been used for indoors localization purposes due to its important advantag... more Traditionally, WiFi has been used for indoors localization purposes due to its important advantages. There are WiFi access points in most buildings and measuring WiFi signal is free of charge even for private WiFi networks. Unfortunately, it also has some disadvantages: when extending WiFi-based localization systems to large environments their accuracy decreases. This has been previously solved by manually dividing the environment into zones. In this paper, an automatic partition of the environment is proposed to increase the localization accuracy in large environments. To do so, a hierarchical partition of the environment is performed using K-Means and the Cali´nski-Harabasz Index. Then, different classification techniques have been compared to achieve high localization rates. The new approach is tested in a real environment with more than 200 access points and 133 topological positions, obtaining an overall increase in the accuracy of approximately 10% and reducing the error to th...

2014 Ubiquitous Positioning Indoor Navigation and Location Based Service (UPINLBS), 2014

ABSTRACT Traditionally, WiFi has been used for indoors localization purposes due to its important... more ABSTRACT Traditionally, WiFi has been used for indoors localization purposes due to its important advantages. First, it is already deployed and its coverage is quickly growing. Second, measuring the WiFi signal strength is free of charge for every WiFi network. Unfortunately, it also has some disadvantages: when extending WiFi-based localization systems to large environments with a high number of APs and positions their accuracy decreases. This has been previously solved by manually dividing the environment into sub-regions. In this paper, an automatic division of the environment using different clustering techniques is proposed. Then the final position is computed by classifying in two different levels (first for a zone, then for a position inside it) using a hierarchical approach. The final performance of the system was improved by dividing the environment in zones obtaining an overall increase in the accuracy of approximately 5%. This indicates that by dividing the environment the overall performance can be improved.

ETFA 2009 - 2009 IEEE Conference on Emerging Technologies and Factory Automation, 2009

The goal of this paper is to study some of the most important WiFi signal variations, large and s... more The goal of this paper is to study some of the most important WiFi signal variations, large and small scale variations and how they affect to WiFi localization systems. Moreover, the paper shows how to use Soft Computing techniques to deal with these uncertainties in WiFi localization systems. This work describes how to reduce uncertainty produced by small scale variations in indoor environments using fuzzy techniques. Some experimental results and conclusions are presented.

IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC, 2010

This paper presents a non intrusive approach to obtain driver's face pose estimation based on ste... more This paper presents a non intrusive approach to obtain driver's face pose estimation based on stereo graylevel image processing. Face pose estimation is based on an automatic and incremental 3D model creation and its correct tracking. From this information, gaze focalization in the scene is calculated in order to detect driver distraction. Different distraction activities are inferred in a realistic simulator and a study of the incidence of these distracting activities in the driver's behaviour is carried out. Some experimental results and conclusions are presented.

IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC, 2011

Driving inattention is a major factor to highway crashes. The National Highway Traffic Safety Adm... more Driving inattention is a major factor to highway crashes. The National Highway Traffic Safety Administration (NHTSA) estimates that approximately 25% of police-reported crashes involve some form of driving inattention. Increasing use of in-vehicle information systems (IVISs) such as cell phones or GPS navigation systems has exacerbated the problem by introducing additional sources of distraction. Enabling drivers to benefit from IVIS without diminishing safety is an important challenge. In this paper, an automatic distraction monitoring system based on gaze focalization for the assessment of IVISs induced distraction is presented. Driver's gaze focalization is estimated using a non-intrusive vision-based approach. This system has been tested in a naturalistic simulator with more than 15 hours of driving in different scenarios and conditions and 12 different professional drivers. The purpose of this work is, on the one hand, to assess the detection capacity of the monitoring system and, in the other hand, to study drivers reactions to different IVISs. Gathering this information the optimal IVISs location and the way the indications should be delivered to the drivers can be studied to reduce the interference with their driving.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2012

Mapping techniques based on Wireless Range-Only Sensors (WROS) consist of locating the beacons us... more Mapping techniques based on Wireless Range-Only Sensors (WROS) consist of locating the beacons using distance measurements only. In this work we use WROS working at 2.4GHz band (same as WiFi), which has the disadvantage of being affected by a high noise. The goal of this paper is to study a noisy range-only sensor and its application in the development of mapping systems. A particle filter is used in order to map the environment, this technique has been applied successfully with other technologies, like ultra-wide band (UWB), but we demonstrate that even using a much more noisy sensor this technique can be applied correctly.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2012

In this paper we present a technique to build 3D maps of the environment using a 2D laser scanner... more In this paper we present a technique to build 3D maps of the environment using a 2D laser scanner combined with a robot's action model. This paper demonstrates that it is possible to build 3D maps in a cheap way using an angled 2D laser. We introduce a scan matching method to minimize the odometer errors of the robotics platform. Some experimental results and conclusions are presented.

Advances in Intelligent Systems and Computing, 2014

ABSTRACT This paper presents different techniques to achieve the tasks proposed in the DARPA (Def... more ABSTRACT This paper presents different techniques to achieve the tasks proposed in the DARPA (Defense Advanced Research Projects Agency) VRC (Virtual Robotics Challenge), which entails the recognition of objects, the robot localization and the mapping of the simulated environments in the Challenge. Data acquisition relies on several sensors such as a stereo camera, a 2D laser, an IMU (Inertial Motion Unit) and stress sensors. Using the map and the position of the robot inside it, we propose a safe path planning to navigate through the environment using an Atlas humanoid robot.

2011 IEEE International Symposium on Industrial Electronics, 2011

This paper describes a new approach for improving the estimation of the global position of a vehi... more This paper describes a new approach for improving the estimation of the global position of a vehicle in complex urban environments by means of visual odometry and map fusion. The visual odometry system is based on the compensation of the heterodasticity in the 3D input data using a weighted nonlinear least squares based system. RANdom SAmple Consensus (RANSAC) based on Mahalanobis distance is used for outlier removal. The motion trajectory information is used to keep track of the vehicle position in a digital map during GPS outages. The final goal is the autonomous vehicle outdoor navigation in large-scale environments and the improvement of current vehicle navigation systems based only on standard GPS. This research is oriented to the development of traffic collective systems aiming vehicle-infrastructure cooperation to improve dynamic traffic management. We provide examples of estimated vehicle trajectories and map fusion using the proposed method and discuss the key issues for further improvement.

Advances in Intelligent Systems and Computing, 2014

2014 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE), 2014