Detection of visitors in elderly care using a low-resolution visual sensor network

Loneliness is a common condition associated with aging and comes with extreme health consequences including decline in physical and mental health, increased mortality and poor living conditions. Detecting and assisting lonely persons is therefore important-especially in the home environment. The current studies analyse the Activities of Daily Living (ADL) usually with the focus on persons living alone, e.g., to detect health deterioration. However, this type of data analysis relies on the assumption of a single person being analysed, and the ADL data analysis becomes less reliable without assessing socialization in seniors for health state assessment and intervention. In this paper, we propose a network of cheap low-resolution visual sensors for the detection of visitors. The visitor analysis starts by visual feature extraction based on foreground/background detection and morphological operations to track the motion patterns in each visual sensor. Then, we utilize the features of the visual sensors to build a Hidden Markov Model (HMM) for the actual detection. Finally, a rule-based classifier is used to compute the number and the duration of visits. We evaluate our framework on a real-life dataset of ten months. The results show a promising visit detection performance when compared to ground truth

Hardware-Aware Performance Evaluation for the Co-Design of Image Sensors and Vision Algorithms

The top-down approach to system design allows obtaining separate specifications for each subsystem. In the case of vision systems, this means propagating system-level specifications down to particular specifications for e. g. the image sensor, the image processor, etc. This permits to adopt different design strategies for each one of them, as long as they meet their own specifications. This approach can lead to over-design, which is not always affordable. Conversely, if higher-level specifications are too tight, they can lead to impossible specifications at the lower levels. This is certainly the case for embedded vision systems in which high-performance needs to be paired with a very restricted power budget. In order to explore alternative architectures, we need tools that allow for simultaneous optimization of different blocks. However, the link between low-level non-idealities and high-level performance is missing. CAD tools for the design and verification of analog and mixed-signal integrated circuits are not well suited for the simulation of higher-level functionalities. Our approach is to extract relevant data from circuit-level simulation and to build an OpenCV model to be employed in the design of the algorithm. The utility of this approach is illustrated by the evaluation of the effect of column-wise and pixel-wise FPN at the sensor on the performance of Viola-Jones face detection

Compressive Imaging Using RIP-Compliant CMOS Imager Architecture and Landweber Reconstruction

In this paper, we present a new image sensor architecture for fast and accurate compressive sensing (CS) of natural images. Measurement matrices usually employed in CS CMOS image sensors are recursive pseudo-random binary matrices. We have proved that the restricted isometry property of these matrices is limited by a low sparsity constant. The quality of these matrices is also affected by the non-idealities of pseudo-random number generators (PRNG). To overcome these limitations, we propose a hardware-friendly pseudo-random ternary measurement matrix generated on-chip by means of class III elementary cellular automata (ECA). These ECA present a chaotic behavior that emulates random CS measurement matrices better than other PRNG. We have combined this new architecture with a block-based CS smoothed-projected Landweber reconstruction algorithm. By means of single value decomposition, we have adapted this algorithm to perform fast and precise reconstruction while operating with binary and ternary matrices. Simulations are provided to qualify the approach.Ministerio de Economía y Competitividad TEC2015-66878-C3-1-RJunta de Andalucía TIC 2338-2013Office of Naval Research (USA) N000141410355European Union H2020 76586

Low-Power CMOS Vision Sensor for Gaussian Pyramid Extraction

This paper introduces a CMOS vision sensor chip in a standard 0.18 μm CMOS technology for Gaussian pyramid extraction. The Gaussian pyramid provides computer vision algorithms with scale invariance, which permits having the same response regardless of the distance of the scene to the camera. The chip comprises 176×120 photosensors arranged into 88×60 processing elements (PEs). The Gaussian pyramid is generated with a double-Euler switched capacitor (SC) network. Every PE comprises four photodiodes, one 8 b single-slope analog-to-digital converter, one correlated double sampling circuit, and four state capacitors with their corresponding switches to implement the double-Euler SC network. Every PE occupies 44×44 μm2 . Measurements from the chip are presented to assess the accuracy of the generated Gaussian pyramid for visual tracking applications. Error levels are below 2% full-scale output, thus making the chip feasible for these applications. Also, energy cost is 26.5 nJ/px at 2.64 Mpx/s, thus outperforming conventional solutions of imager plus microprocessor unit.Office of Naval Research, USA N00014-14-1-0355Ministerio de Economía y Competitividad TEC2015-66878- C3-1-R, TEC2015-66878-C3-3-RJunta de Andalucía TIC 2338, EM2013/038, EM2014/01

PyHGL: A Python-based Hardware Generation Language Framework

Hardware generation languages (HGLs) increase hardware design productivity by creating parameterized modules and test benches. Unfortunately, existing tools are not widely adopted due to several demerits, including limited support for asynchronous circuits and unknown states, lack of concise and efficient language features, and low integration of simulation and verification functions. This paper introduces PyHGL, an open-source Python framework that aims to provide a simple and unified environment for hardware generation, simulation, and verification. PyHGL language is a syntactical superset of Python, which greatly reduces the lines of code (LOC) and improves productivity by providing unique features such as dynamic typing, vectorized operations, and automatic port deduction. In addition, PyHGL integrates an event-driven simulator that simulates the asynchronous behaviors of digital circuits using three-state logic. We also propose an algorithm that eliminates the calculation and transmission overhead of unknown state propagation for binary stimuli. The results suggest that PyHGL code is up to 6.1x denser than traditional RTL and generates high-quality synthesizable RTL code. Moreover, the optimized simulator achieves 2.9x speed up and matches the performance of a commonly used open-source logic simulator

WoX+: A Meta-Model-Driven Approach to Mine User Habits and Provide Continuous Authentication in the Smart City

The literature is rich in techniques and methods to perform Continuous Authentication (CA) using biometric data, both physiological and behavioral. As a recent trend, less invasive methods such as the ones based on context-aware recognition allows the continuous identification of the user by retrieving device and app usage patterns. However, a still uncovered research topic is to extend the concepts of behavioral and context-aware biometric to take into account all the sensing data provided by the Internet of Things (IoT) and the smart city, in the shape of user habits. In this paper, we propose a meta-model-driven approach to mine user habits, by means of a combination of IoT data incoming from several sources such as smart mobility, smart metering, smart home, wearables and so on. Then, we use those habits to seamlessly authenticate users in real time all along the smart city when the same behavior occurs in different context and with different sensing technologies. Our model, which we called WoX+, allows the automatic extraction of user habits using a novel Artificial Intelligence (AI) technique focused on high-level concepts. The aim is to continuously authenticate the users using their habits as behavioral biometric, independently from the involved sensing hardware. To prove the effectiveness of WoX+ we organized a quantitative and qualitative evaluation in which 10 participants told us a spending habit they have involving the use of IoT. We chose the financial domain because it is ubiquitous, it is inherently multi-device, it is rich in time patterns, and most of all it requires a secure authentication. With the aim of extracting the requirement of such a system, we also asked the cohort how they expect WoX+ will use such habits to securely automatize payments and identify them in the smart city. We discovered that WoX+ satisfies most of the expected requirements, particularly in terms of unobtrusiveness of the solution, in contrast with the limitations observed in the existing studies. Finally, we used the responses given by the cohorts to generate synthetic data and train our novel AI block. Results show that the error in reconstructing the habits is acceptable: Mean Squared Error Percentage (MSEP) 0.04%

Sviluppo di una app di ausilio per persone non vedenti per Android

La tesi prevede lo sviluppo di una app di ausilio per persone non vedenti per ambiente Android. L'applicazione ha due scopi principali: rilevazione degli ostacoli che l'utente incontra nel proprio cammino, tramite un apposito visore, con successivo invio di informazioni sugli ostacoli rilevati tramite output audio e tattili e realizzazione di una versione personalizzata di Google Maps che l'utente può utilizzare nella maniera più comoda e sicura possibile

Contributions to autonomous robust navigation of mobile robots in industrial applications

151 p.Un aspecto en el que las plataformas móviles actuales se quedan atrás en comparación con el punto que se ha alcanzado ya en la industria es la precisión. La cuarta revolución industrial trajo consigo la implantación de maquinaria en la mayor parte de procesos industriales, y una fortaleza de estos es su repetitividad. Los robots móviles autónomos, que son los que ofrecen una mayor flexibilidad, carecen de esta capacidad, principalmente debido al ruido inherente a las lecturas ofrecidas por los sensores y al dinamismo existente en la mayoría de entornos. Por este motivo, gran parte de este trabajo se centra en cuantificar el error cometido por los principales métodos de mapeado y localización de robots móviles,ofreciendo distintas alternativas para la mejora del posicionamiento.Asimismo, las principales fuentes de información con las que los robots móviles son capaces de realizarlas funciones descritas son los sensores exteroceptivos, los cuales miden el entorno y no tanto el estado del propio robot. Por esta misma razón, algunos métodos son muy dependientes del escenario en el que se han desarrollado, y no obtienen los mismos resultados cuando este varía. La mayoría de plataformas móviles generan un mapa que representa el entorno que les rodea, y fundamentan en este muchos de sus cálculos para realizar acciones como navegar. Dicha generación es un proceso que requiere de intervención humana en la mayoría de casos y que tiene una gran repercusión en el posterior funcionamiento del robot. En la última parte del presente trabajo, se propone un método que pretende optimizar este paso para así generar un modelo más rico del entorno sin requerir de tiempo adicional para ello