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This paper presents a Power Management Unit (PMU) powered by a 1 mm $^2$ solar cell on the same substrate to rise up the harvested voltage above 1.1 V. The on-chip solar cell and the PMU are fabricated in standard 0.18 μm CMOS technology achieving a form factor of 1.575 mm $^2$ . The PMU is able to start up from a harvested power of 2.38 nW without any external kick off or control signal. The PMU features a continuous and two-dimensional Maximum Power Point Tracking (MPPT) working in open-loop mode to handle a harvested power range from nW to $\mu$ W, by modifying both the charge pump topology and the switching frequency. The MPPT is based on four voltage level detectors that define five working regions depending on the illumination and on a self-tuning reference current for a fine adjustment of the switching frequency. The chip also includes an auxiliary charge pump to generate the voltage level necessary for the control circuit, implemented as a Pelliconi charge pump of 8 stages with NMOS transistors in Pwell as diodes. A Dickson charge pump with transmission gates as switches and with variable gain and capacitance per stage is also designed as the main charge pump. Finally, two relaxation oscillators are implemented to drive both charge pumps. This paper is accompanied by a video file demonstrating the PMU operation by powering an off-chip NAND gate This work has been partially funded by Spanish government project TEC2015-66878-C3-3-R MINECO (FEDER), in part by Xunta de Galicia under Project ED431C2017/69, in part by the Consellería de Cultura, Educación e Ordenación Universitaria (accreditation 2016-2019, ED431G/08) and the European Regional Development Fund (ERDF), and in part by Xunta de Galicia and the European Union (European Social Fund - ESF) SI

Wireless sensor networks (WSNs) are increasingly adopted in agriculture to monitor environmental variables to predict the presence of pests. Differently from these approaches, this paper introduces aWSN to detect the presence of snails in the field. The network can be used to both trigger an alarm of early pest presence and to further elaborate statistical models with the addition of environmental data as temperature or humidity to predict snail presence. In this paper we also design our own WSN simulator to account for real-life conditions as an uneven spacing of motes in the field or different currents generated by solar cells at the motes. This allows achieving more realistic network deployment in the field. Experimental tests are included in this paper, showing that our motes are perpetual in terms of energy consumption Consellería de Cultura, Educación e Ordenación Universitaria (accreditation 2016-2019); European Regional Development Fund; Ministerio de Economía, Industria y Competitividad (TEC2015-66878-C3-3-R) SI

Unlike other noise sources, which can be reduced or eliminated by different signal processing techniques, shot noise is an ever-present noise component in any imaging system. In this paper, we present an in-depth study of the impact of shot noise on time-of-flight sensors in terms of the error introduced in the distance estimation. The paper addresses the effect of parameters, such as the size of the photosensor, the background and signal power or the integration time, and the resulting design trade-offs. The study is demonstrated with different numerical examples, which show that, in general, the phase shift determination technique with two background measurements approach is the most suitable for pixel arrays of large resolution This work has been partially funded by Spanish government Project TEC2012-38921-C02-02 MINECO(FEDER) and by the Xunta de Galicia with EM2013/038 and EM2014/012, AE CITIUS(CN2012/151, (FEDER)) and GPC2013/040 (FEDER) SI

Comunicación presentada al "ISCAS 2012" celebrado en Seúl (Corea del Sur) del 20 al 23 de Mayo del 2012., This paper introduces an architecture of a switched-capacitor network for Gaussian pyramid generation. Gaussian pyramids are used in modern scale- and rotation-invariant feature detectors or in visual attention. Our switched-capacitor architecture is conceived within the framework of a CMOS-3D-based vision system. As such, it is also used during the acquisition phase to perform analog storage and Correlated Double Sampling (CDS). The paper addresses mismatch, and switching errors like feedthrough and charge injection. The paper also gives an estimate of the area occupied by each pixel on the 130nm CMOS-3D technology by Tezzaron. The validity of our proposal is assessed through object detection in a scale- and rotation-invariant feature detector., This work has been funded by Xunta de Galicia (Spain) and MICINN (Spain) through projects 10PXIB206037PR and TEC2009-12686, and by ONR through Project N000141110312.

Although land mine problems existed in many regions, Bosnia (1995) and Afghanistan (2001) gave the land mine issue a particular sense of urgency. Intended for warfare, these mines remain buried after the end of the conflict. These mines are triggered by civilians causing around 15,000-20,000 victims per year in 90 countries, ICBL (2006). The U.S. State Department estimates that there are around 40-50 million of buried mines that need to be cleared. According to Horowitz (1996) 100,000 mines are found and destroyed per year; thus 450 years will be necessary to clean all mines. However, each year, 1.9 million of new mines are buried. In addition, the presence of mines also causes economic decline being one of the major limitations to agricultural work on these regions, Cameron & Lawson (1998). Thus, it is necessary to develop new techniques which allow to detect mines quickly and with high precision. The Ottawa treaty, Ottawa (1997), banning the production and use of AP mines was signed by 158 countries in 2007 however the most important AP manufacturers, China, Russia, India and EE.UU, have not yet signed it. Nowadays more than 350 types of mines exist, Vines & Thompson (1999); but they can be broadly divided into two main categories

This paper targets the efficient computational solution of the heat transfer processes that take place in the soil and at the soil-air interface and its use in non-destructive evaluation (NDE) techniques. In particular, the problem of the detection of plastic antipersonnel mines is considered. To this aim we projected a 3D finite-difference (FD) thermal model of the soil on a FPGA platform using Handel-C and VHDL. A speedup factor of 34 over a purely software solution is achieved, obtaining processing times that permit the use of the system on the field.

Soil inspection by means of non-destructive evaluation (NDE) methods constitutes a subject of great research interest with practical implications beyond a particular domain of application. NDE methods often require the modelling of physical phenomena involving complex sets of equations whose computational solution has demanding requirements in terms of memory and computing power. One case of particular importance is that of the heat transfer equation, present in multiple situations. In this article, we will focus on NDE for soil inspection, with a particular application on the detection of shallowly buried antipersonnel mines in sandy soils. To this aim, a quasi-inverse procedure for the estimation of the depth of burial of the mine targets, and a full-inverse procedure for the characterization of the physical properties of other targets will be proposed. The efficient computational solution of these procedures is ensured via a software-hardware heat equation solver presented here

The use of infrared (IR) images of the soil is an efficient technique to detect shallowly buried landmines. The detection is possible due to the different thermal properties of the soil and the mine. The core of this technique is the simulation of the heat transfer processes in the soil and at the soil-air interface. Simulation of these processes is a very long-time consuming task on ordinary computers. Its execution on dedicated hardware can reduce the computing time. In this paper we show the architecture of a system that simulates the thermal processes onto an FPGA, showing the feasibility of such a realization.

In this paper, we address the problem of the detection and identification of surface-laid and shallowly buried landmines from measured infrared images. A three-dimensional thermal model has been developed to study the effect of the presence of landmines in the thermal signature of the bare soil. Based on this model, a target identification procedure is proposed aiming at detecting and classifying the anomalies found on the soil thermal signature. In our approach, landmines are thought of as a thermal barrier in the natural flow of the heat inside the soil, which produces a perturbation of the expected thermal pattern on the surface. The detection of these perturbations will put into evidence the presence of potential mine targets. We propose an iterative procedure to classify the detected perturbations as mines or nonmines and to estimate their depth of burial. This paper describes the main principles of our method and illustrates classification results on a set of acquired images. Qualitative and quantitative comparisons with independent component analysis are also given.

Total knee replacement (TKR) is a surgical procedure used by orthopaedic surgeons. It requires an adequate preoperative planning. Several parameters involved in this planning are usually obtained by manually measuring on radiographic images (91.44 cm cassette for alignment film in weight bearing stance). We have devised a system which makes it possible to automate the measurements. It automatically finds the cortical bone internal and external contours from full femur and tibia. Detection of bone boundaries is achieved using active contours. The snake is initialized with the interactive definition of a poligonal contour on the radiographic image. From the obtained contours, the parameters can be easily derived. The system speeds up the measuring processes and eliminates subjectivity.