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Background:Catheter ablation is a safe and effective therapy for the treatment of supraventricular tachycardia in children. Current improvements in technology have allowed progressive reduction in radiation exposure associated with the procedure. To assess the impact of three-dimensional mapping, we compared acute procedural results collected from the Catheter Ablation with Reduction or Elimination of Fluoroscopy registry to published results from the Prospective Assessment after Pediatric Cardiac Ablation study.Methods:Inclusion and exclusion criteria from the Prospective Assessment after Pediatric Cardiac Ablation study were used as guidelines to select patient data from the Catheter Ablation with Reduction or Elimination of Fluoroscopy registry to compare acute procedural outcomes between cohorts. Outcomes assessed include procedural and fluoroscopy exposure times, success rates of procedure, and complications.Results:In 786 ablation procedures, targeting 498 accessory pathways and 288 atrioventricular nodal reentrant tachycardia substrates, average procedural time (156.5 versus 206.7 minutes, p < 0.01), and fluoroscopy time (1.2 versus 38.3 minutes, p < 0.01) were significantly shorter in the study group. Success rates for the various substrates were similar except for manifest accessory pathways which had a significantly higher success rate in the study group (96.4% versus 93.0%, p < 0.01). Major complication rates were significantly lower in the study group (0.3% versus 1.6%, p < 0.01).Conclusions:In a large, multicentre study, three-dimensional systems show favourable improvements in clinical outcomes in children undergoing catheter ablation of supraventricular tachycardia compared to the traditional fluoroscopic approach. Further improvements are anticipated as technology advances.

We herein report a 79-year-old man with recurrent atrial flutter (AFL) following catheter ablation for pulmonary vein (PV) isolation and block line of the cavotricuspid isthmus. An electrophysiological study and three-dimensional mapping results revealed left atrium (LA)-PV macroreentrant flutter caused by a conduction gap, possibly correlated to prior application, which mimicked cavotricuspid isthmus-dependent AFL. This LA-PV flutter was terminated after applying radiofrequency to the gap at the antrum near the bottom left inferior PV in the posterior LA wall. During follow-up, the patient did not present with atrial tachyarrhythmias; antiarrhythmic drugs were therefore not administered.

Background:Patients with CHD can be exposed to high levels of cumulative ionising radiation. Utilisation of electroanatomic mapping during catheter ablation leads to reduced radiation exposure in the general population but has not been well studied in patients with CHD. This study evaluated the radiation sparing benefit of using three-dimensional mapping in patients with CHD.Methods:Data were retrospectively collected from the Catheter Ablation with Reduction or Elimination of Fluoroscopy multi-institutional registry. Patients with CHD were selected. Those with previous ablations, concurrent diagnostic or interventional catheterisation and unknown arrhythmogenic foci were excluded. The control cohort was matched for operating physician, arrhythmia mechanism, arrhythmia location, weight and age. The procedure time, rate of fluoroscopy use, fluoroscopy time, procedural success, complications, and distribution of procedures per year were compared between the two groups.Results:Fifty-six patients with congenital heart disease and 56 matched patients without CHD were included. The mean total procedure time was significantly higher in patients with CHD (212.6 versus 169.5 minutes, p = 0.003). Their median total fluoroscopy time was 4.4 minutes (compared to 1.8 minutes), and their rate of fluoroscopy use was 23% (compared to 13%). The acute success and minor complication rates were similar and no major complications occurred.Conclusions:With the use of electroanatomic mapping during catheter ablation, fluoroscopy use can be reduced in patients with CHD. The majority of patients with CHD received zero fluoroscopy.

Three-dimensional mapping is an essential component of autonomous Micro Aerial Vehicle (MAV) navigation. The paper focuses on the 3D spatial representation method of MAV to overcome the collision problem caused by soft constraints, control error, and planning with the center of mass by inflating the occupancy grid map. A fast incremental inflated map construction method is proposed, which reduces the time-consumption caused by the increase of map range and inflated size. The method focuses on areas of the map that occupied state changes and introduces two arrays that record newly appearing and disappearing obstacles. Then, a series of breadth-first search algorithms are used to traverse the parts of the inflated map that need local modification to update the inflated map. Moreover, a sliding map model is designed based on the MAV position, which is suitable for large-range autonomous flight. The effectiveness of the proposed approach is verified with simulated and actual flight data. The proposed method takes about 3 ms to construct the inflated map with a local update range of 16 m × 16 m × 6 m.

A 51-year-old man, who had a history of open heart surgery for corrected transposition of great arteries, presented with palpitation due to atrial tachycardia. A propagation map using three-dimensional electroanatomical mapping (CARTO3) showed atrial flutter and underwent linear ablation successfully. This case highlights the difficulty of diagnosis before mapping following a complicated cardiac operation and the usefulness of three-dimensional mapping.

A 17‐year‐old woman presented with frequent palpitations and shortness of breath and was diagnosed with drug‐refractory ventricular parasystole. We predicted that the parasystole originated from the left anterior fascicle (LAF). Detailed activation maps of both conduction systems, including the LAF, during sinus rhythm and ventricular parasystole were obtained using a parallel mapping system. We confirmed the earliest fascicular potential of the parasystole and performed catheter ablation with no complications. This novel mapping algorithm for simultaneous acquisition of multiple maps aided effective treatment of ventricular parasystole originating from the LAF., Ventricular parasystole originating from the left anterior fascicle can be effectively eliminated by using this novel mapping algorithm of parallel mapping and LAT hybrid mapping. Parallel mapping makes it possible to obtain both activation maps during ventricular parasystole and sinus rhythm simultaneously, decreasing the procedure time while also increasing efficacy. LAT hybrid mapping also makes it possible for precise positioning during parasystole ablation.

Background Conduction channels have been demonstrated within the postinfarct scar and seem to be co-located with the isthmus of ventricular tachycardia (VT). Mapping the local scar potentials (SPs) that define the conduction channels is often hindered by large far-field electrograms generated by healthy myocardium. Objective The purpose of this study was to map conduction channel using ripple mapping to categorize SPs temporally and anatomically. We tested the hypothesis that ablation of early SPs would eliminate the latest SPs without direct ablation. Methods Ripple maps of postinfarct scar were collected using the PentaRay (Biosense Webster) during normal rhythm. Maps were reviewed in reverse, and clusters of SPs were color-coded on the geometry, by timing, into early, intermediate, late, and terminal. Ablation was delivered sequentially from clusters of early SPs, checking for loss of terminal SPs as the endpoint. Results The protocol was performed in 11 patients. Mean mapping time was 65 ± 23 minutes, and a mean 3050 ± 1839 points was collected. SP timing ranged from 98.1 ± 60.5 ms to 214.8 ± 89.8 ms post QRS peak. Earliest SPs were present at the border, occupying 16.4% of scar, whereas latest SPs occupied 4.8% at the opposing border or core. Analysis took 15 ± 10 minutes to locate channels and identify ablation targets. It was possible to eliminate latest SPs in all patients without direct ablation (mean ablation time 16.3 ± 11.1 minutes). No VT recurrence was recorded (mean follow-up 10.1 ± 7.4 months). Conclusion Conduction channels can be located using ripple mapping to analyze SPs. Ablation at channel entrances can eliminate the latest SPs and is associated with good medium-term results.

The majority of electrophysiologists routinely use fluoroscopy (FLUORO) during ablation procedures for common arrhythmias despite the known complications of radiation exposure and protective lead use. This study assessed the safety of catheter ablation (CA) with FLUORO versus without FLUORO (SANS FLUORO) in patients with the following common arrhythmias: atrial fibrillation (AF), atrial flutter, supraventricular tachycardia, and ventricular tachycardia. A total of 1,258 CA procedures were performed in 816 consecutive patients over a 53-month period (SANS FLUORO CA: 609 patients; FLUORO CA: 209 patients). The secondary outcome was the efficacy of AF ablation in FLUORO versus SANS FLUORO patients. Ultimately, there was no statistically significant difference found concerning the safety of CA in the SANS FLUORO and FLUORO groups in terms of procedure time, vascular complications, tamponade, stroke, or death. FLUORO patients had markedly increased FLUORO time, increased radiation exposure, and increased dose-area product (all p < 0.0001). AF development after SANS FLUORO CA of AF was not different from that after FLUORO CA regardless of the pulmonary vein isolation (PVI) modality used (cryoablation versus radiofrequency) at 24 months (p = 0.21). Additionally, women fared just as well as men after CA ablation for AF. At 36 months, 58% of SANS FLUORO AF device patients were free from AF. As such, SANS FLUORO CA of common arrhythmias appears to be as safe as FLUORO CA but with a markedly reduced level of radiation exposure. Also, SANS FLUORO CA remains as effective as FLUORO CA in the prevention of AF for up to 24 months.

BackgroundDenis and Ferguson et al.’s three-column spinal theory has been widely accepted and applied. However, this three-column theory was proposed based solely on observation and experience without thorough documented data and analysis. The aim of this study was to analyze and improve Denis and Ferguson et al.’s three-column spinal theory to propose a novel three-column concept in epidemiology, morphology and biomechanics.MethodsA retrospective analysis of the computed tomography imaging data of patients with a diagnosis of T11-L5 vertebral fractures was conducted between February 2010 and December 2018. Three-dimensional (3D) distribution maps of fracture lines of all subjects were obtained based on 3D mapping techniques. In addition, a 25-year-old health male volunteer was recruited for the vertebral finite element force analysis.ResultsThe present study enrolled 459 patients (age: 48 ± 11.42 years), containing a total of 521 fractured vertebrae. The fracture lines peaked in the upper and the outer third sections of the vertebra, starting from the anterior part of the vertebral pedicles in 3-D maps. Regarding flexion and extension of the spine, the last third of the vertebral body in front of the spinal canal was one main stress center in the finite element analysis. The stress on the vertebral body was greater in front of the pedicles in the lateral bending.ConclusionThe study reveals that the posterior one-third of the vertebral body in front of the spinal canal and the posterior one-third of the vertebral body in front of the pedicle are very different in terms of fracture characteristics and risks to spinal canal (3D maps and stress distributing graphs), therefore, they should be classified as different columns. We provide strong evidence that Su’s three-column theory complies with the characteristics of vertebral physiological structure, vertebral fracture, and vertebral biomechanics.Graphical abstract

Soil salinity is an active and complex part of soil property in arid and semiarid irrigation areas that restricts the sustainability of agriculture production. Knowledge of seasonal distributions and migration of soil salinity is important for the management of agriculture. In this study, three-dimensional (3-D) geostatistical methods were used to construct seasonal 3-D spatial distribution maps of soil salinity, and then the quantitative analysis methods were used to study the seasonal accumulation patterns of soil salinity for the 0&ndash, 150 cm soil depth in cold and semiarid irrigated rice fields. The results revealed that there were different spatial distribution and migration patterns of soil salinity in autumn 2015, spring 2016, autumn 2016, and spring 2017. The migration of soil salinity had a dispersion trend from autumn to spring, and the area of non-saline soil increased. Whereas there was an accumulation trend from spring to autumn, and the area of non-saline soil decreased. There were about 10&ndash, 20% of the study area had experienced transitional changes of different soil salinity levels in different seasons. The correlation coefficient showed that there were significant positive correlations among the five depth increments (30 cm) in different seasons, and the correlations of soil salinity were higher in adjacent layers than in nonadjacent layers. The ECe values were higher in the topsoil (0&ndash, 30 cm) and deeper subsoil (120&ndash, 150 cm), indicating that soil soluble salts accumulated in the soil surface due to evaporation and accumulated in the bottom due to leaching and drainage. Microtopography was the major factor influencing spatial distribution of soil salinity in different seasons. The ECe values were generally higher in the swales or in areas with rather poor drainage, whereas the values were lower in relatively higher-lying slopes or that were well-drained. The results provide theoretical basis and reference for studying the variation of seasonal soil salinity in irrigated fields.

Atypical left atrial flutters present following atrial fibrillation ablation have been well-documented in the literature. These arrhythmias are known to be difficult to localize and ablate. An atypical flutter with an alternating activation pattern in the coronary sinus, however, is unusual and has rarely been discussed. In this case report, we describe the use of high-density three-dimensional anatomic mapping to successfully localize and terminate an atypical flutter with an alternating atrial activation pattern in the coronary sinus.

Voltage mapping has been used previously for slow-pathway localization for atrioventricular nodal reentrant tachycardia (AVNRT) ablation. However, propagation mapping may be a technique to further improve the localization of the slow pathway. This retrospective study aimed to evaluate the relationship of the propagation map to both the voltage mapping and successful site of ablation in patients who underwent ablation for AVNRT. All patients ≤20 years of age who underwent voltage mapping for AVNRT were included in this study. Patients were excluded if they had congenital heart disease or inadequate voltage point density within the triangle of Koch (TK). During the study, a propagation map was evaluated from the prior voltage map, marking a "wave collision" at the site of atrial wave convergence. Patient and procedural information, the location of the wave collision, the site of successful ablation, and the appearance of the voltage map were evaluated. Ultimately, 39 patients aged from four years of age to 20 years of age were evaluated. Success was achieved in 100% of patients, with a recurrence rate of 2.8% and no long-term complications observed. The average procedure time was 127 min. Follow-up length averaged seven months post operation. Low-voltage areas, and a wave collision, were present in all patients. This wave collision was typically located within the TK. The median number of ablations required for successful outcome was two. The successful ablation lesion was typically located over a low-voltage area within 4 mm of the wave collision within the TK. In conclusion, we found in this retrospective evaluation that propagation mapping resulted in a wave collision within the TK, and that the successful ablation site in the majority of patients was near a low-voltage area within 4 mm, typically superiorly, to the wave collision within the TK.

Diese theoretische Arbeit hat das Ziel, einen allgemeinen Überblick über das dreidimensionale Mapping zu verschaffen. Im Zuge dessen wird auf zwei Mappingsysteme, CARTO®3 und EnSite Pecision™, näher eingegangen. Die technischen Gegebenheiten zur Generierung der Katheterposition sowie die Zusammensetzung der benötigten Komponenten werden behandelt. Der genaue Untersuchungsablauf inklusive davor stattzufindender Vorbereitung wird dargelegt, zentrale Fragen zu den technischen Aspekten, dem Untersuchungsablauf und der Vorbereitung auf ein Mapping werden erarbeitet. Der Inhalt dieser theoretischen Arbeit wird aus den Datenbanken PubMed, SpringerLink und ScienceDirect erhoben. Informationen über die diversen Mappingsysteme werden bei den Herstellern eingeholt. Bücher, Arbeiten sowie Fachstudien, die dieses Thema ebenfalls behandeln, werden aus der Bibliothek ausgeliehen. Es werden deutsch- und englischsprachige aktuelle Studien der Jahre 2015-2020 herangezogen. Studien zeigen, dass es keine großen Unterschiede zwischen konventionellem und dreidimensionalen Mapping in punkto Verfahrenszeit, Erfolgsrate des Verfahrens oder Komplikationen gibt. Daher sollte auf eine nicht fluoroskopische Methode zurückgegriffen werden. Die Beschaffung der Informationen bezüglich der einzelnen Mappingsysteme erfolgt über den jeweiligen Hersteller. Allgemeine Informationen über die Mappingsysteme können aus den Datenbanken gewonnen werden. Allerdings beziehen sich viele Artikel und dergleichen auf die Behandlung einer bestimmten Arrhythmie und nicht auf das Mapping selbst. Der Untersuchungsablauf wird aus den Betriebsanleitungen der jeweiligen Hersteller erarbeitet. This theoretical work aims to provide a general overview of three-dimensional mapping. Two mapping systems, CARTO®3 and EnSite Pecision™, will be discussed in detail. The technical conditions for generating the catheter position as well as the composition of the required components are discussed. The exact examination procedure including the preparation before the examination is explained. Central questions about the technical aspects, the examination procedure and the preparation for a mapping are worked out. The content of this theoretical work is collected from the databases PubMed, SpringerLink and ScienceDirect. Information on the various mapping systems will be obtained from the manufacturers. Books and papers, as well as specialist studies, which also deal with this topic, are borrowed from the library. Current studies in German and English for the years 2015-2020 are used. Studies show that there are no major differences between conventional and threedimensional mapping in terms of procedure time, success rate of the procedure or complications. Therefore a non-fluoroscopic method should be used. Information regarding the individual mapping systems was obtained from the respective manufacturer. General information about the mapping systems could be obtained from the databases. However, many articles and the like referred to the treatment of a specific arrhythmia and not to the mapping itself. The examination procedure was developed from the operating instructions of the respective manufacturers.

Most cultivated upland areas of northeast Thailand are characterized by sandy and infertile soils, which are difficult to improve agriculturally. Information about the clay (%) and cation exchange capacity (CEC&mdash, cmol(+)/kg) are required. Because it is expensive to analyse these soil properties, electromagnetic (EM) induction instruments are increasingly being used. This is because the measured apparent soil electrical conductivity (ECa&mdash, mS/m), can often be correlated directly with measured topsoil (0&ndash, 0.3 m), subsurface (0.3&ndash, 0.6 m) and subsoil (0.6&ndash, 0.9 m) clay and CEC. In this study, we explore the potential to use this approach and considering a linear regression (LR) between EM38 acquired ECa in horizontal (ECah) and vertical (ECav) modes of operation and the soil properties at each of these depths. We compare this approach with a universal LR relationship developed between calculated true electrical conductivity (&sigma, &mdash, mS/m) and laboratory measured clay and CEC at various depths. We estimate &sigma, by inverting ECah and ECav data, using a quasi-3D inversion algorithm (EM4Soil). The best LR between ECa and soil properties was between ECah and subsoil clay (R2 = 0.43) and subsoil CEC (R2 = 0.56). We concluded these LR were unsatisfactory to predict clay or CEC at any of the three depths, however. In comparison, we found that a universal LR could be established between &sigma, with clay (R2 = 0.65) and CEC (R2 = 0.68). The LR model validation was tested using a leave-one-out-cross-validation. The results indicated that the universal LR between &sigma, and clay at any depth was precise (RMSE = 2.17), unbiased (ME = 0.27) with good concordance (Lin&rsquo, s = 0.78). Similarly, satisfactory results were obtained by the LR between &sigma, and CEC (Lin&rsquo, s = 0.80). We conclude that in a field where a direct LR relationship between clay or CEC and ECa cannot be established, can still potentially be mapped by developing a LR between estimates of &sigma, with clay or CEC if they all vary with depth.

BACKGROUND A new three-dimensional heart anatomical simulator (3D HAS) has been created combining a physical heart model with an electroanatomic mapping (EAM) system. The aim of this study is to describe the development and the validation process of this device. METHODS We developed the 3D HAS combining a physical heart model with an EAM system. This simulator was then validated by 10 electrophysiologists, subdivided in two groups based on their experience in electrophysiology procedures. The performance of the experts was compared to the one of the novices in achieving three different tasks: fluoroless reconstruction of the right atrium, coronary sinus cannulation, and deployment of a linear ablation lesion in the cavotricuspid isthmus. For each operator, a score was calculated based on objective parameter for each task and for the overall performance. RESULTS The 3D HAS was located in an environment that allowed use of the main features of the EAM system including contact force sensing. No technical issue was encountered during the validation process. The experts' performance was significantly better than the one of the novices both overall (P = 0.009) and in each task (right atrium reconstruction, P = 0.016; coronary sinus cannulation, P = 0.008; ablation lesion, P = 0.03). CONCLUSIONS The 3D HAS is reliable and allows use of the main features of an EAM system in the right atrium. The ability to discriminate different levels of experience suggests that this simulator is enough realistic and could be useful for electrophysiology training.

We report the use of the Abbott three-dimensional mapping system (EnSite Precision) for the placement of an atrial pacemaker lead in a patient after modified Fontan procedure. The mapping system was used for the identification of a promising pacing site in the complexly modified right atrium and to visualize the successful placement of an atrial lead at the same spot.

Soil Organic Carbon (SOC) is the largest terrestrial pool of carbon (1500Gt), and is an important factor controlling overall soil quality. The quantification of SOC and its change over time is crucial in a context of climate change and concerns about soil fertility. Current methods to assess SOC changes, however, pose some important limitations to our ability to accurately assess SOC dynamics in a spatial and temporal context. The overall aim of this thesis was therefore to improve our capability to assess 3D SOC storage patterns at spatial high resolution and to improve our understanding of the impact of soil movement on SOC storage in an agro-ecosystem. In this thesis, we developed and evaluated a method to predict the vertical SOC profile at a high resolution in a landscape affected by erosion. We show that the surface SOC content is related to soil redistribution processes whereas the shape of the vertical distribution is influenced by the soil moisture and temperature. In a second phase, we developed and evaluated a procedure to measure the surface SOC content at very high resolution using low altitude aerial sensing systems (UAV’s). The method developed permits to map the surface SOC content of arable fields at a resolution of c. 10cm with an accuracy that is similar to those obtained under laboratory conditions. Furthermore, we assessed the potential of combining the UAV-based sensors with the soil profile depth assessments for quantifying the three dimensional SOC distribution. We showed that the remote sensing technique proposed here has a strong potential for 3D mapping due to the strong correlation between the topsoil and subsoil SOC content. However, further research using more performing sensors are needed to control for soil variability (i.e. clay content) that may interfere with the SOC content. Using these new methodologies, we then quantified and evaluated the impact of soil redistribution on three dimensional SOC patterns and its impact on the net C balance for the period 1997-2014. We showed that the texture was a key factor controlling the SOC pattern, but due to the high variability of the SOC and its slow evolution over the time, detecting significant changes was challenging. Nevertheless, our methodology allowed detecting a significant decrease in SOC stock for the topsoil in the eroding areas and an increase in SOC stock for the subsoil layers of stable areas. This analysis was consistent with model-based estimates of changes in SOC stocks in response to erosion and deposition. Finally, this work showed that it is important to further improve methodologies and tools to assess 3D SOC storage in order to obtain a solid SOC baseline when detecting changes in SOC storage. The improvements presented in this thesis provided a significant step in this direction. We conclude that this thesis has improved our understanding of the consequences of erosion on SOC dynamics, and this may provide a basis to manage these impacts to enhance soil fertility but also mitigate climate change. (SC - Sciences) -- UCL, 2017

Summary Background Catheter ablation is widely used to treat symptomatic atrial fibrillation (AF) refractory to drug therapy; and can be facilitated by a number of different techniques. Aims To evaluate our performance as a new centre for AF ablation and to evaluate the efficacy of different AF ablation techniques. Methods We employed three techniques in AF ablations; the three-dimensional (3D) mapping approaches (CARTO® or Ensite NavX®) or multielectrode catheter duty-cycled radiofrequency ablation (pulmonary vein ablation catheter [PVAC®]). The immediate restoration of sinus rhythm was considered as acute success; while success at 6 months was determined by the maintenance of sinus rhythm on Holter monitoring. Results Between March 2008 and March 2010, 109 patients underwent AF ablations (mean age: 58 years; 72% male). Six-month success rates did not differ significantly between CARTO and NavX (40% vs 38%; P = 0.81), but the PVAC group achieved greater success than the two 3D-mapping groups combined (68% vs 39%; P = 0.004). Paroxysmal AF patients demonstrated greater 6-month success than persistent AF patients (P = 0.005); and although the ratio of paroxysmal to persistent AF patients was slightly higher among the PVAC group, logistic regression confirmed PVAC and paroxysmal AF as predictors of success. Single-procedure success at 6 months was 48%. Including redo-ablations, some performed beyond the study period, our overall success rate at 6 months was 65%. Four patients experienced complications, but there were no deaths. Conclusion Despite being a new centre with relative inexperience, we achieved success rates comparable to those of established tertiary centres. PVAC performed significantly better than the two 3D-mapping approaches.

The purpose of this study is to examine a normal conduction pathway of the left atrium. During pulmonary vein isolation using a three-dimensional mapping system, we observed the characteristics of the conduction pattern. Subjects consisted of 15 patients with paroxysmal atrial fibrillation (mean age, 62.8 ± 8.4 years). Left atrial activation conduction begins in the interatrial septum, and moves toward the peak of the ridge between the left atrial appendage and left pulmonary vein. In coronary sinus or appendage pacing, conduction was in the opposite direction at the same location. The mean conduction velocity in this area was 2.03 ± 0.43 m/s. Features of decrement conduction were not present. Anatomical position of the appendage differed greatly between patients. A detailed observation using the inner-cavity view of a three-dimensional mapping system also showed that the peak of the ridge reached the center of the roof.

This thesis investigates the problem of reliably estimating attitude from panoramic imagery in cluttered environments. Accurate attitude is an essential input to the stabilisation systems of autonomous aerial vehicles. A new camera system which combines a CCD camera, UltraViolet (UV) filters and a panoramic mirror-lens is designed. Drawing on biological inspiration from the Ocelli organ possessed by certain insects, UV filtered images are used to enhance the contrast between the sky and ground and mitigate the effect of the sun. A novel method for real–time horizon-based attitude estimation using panoramic image that is capable of estimating an aircraft pitch and roll at a low altitude in the presence of sun, clouds and occluding features such as tree, building, is developed. Also, a new method for panoramic sky/ground thresholding, consisting of a horizon– and a sun–tracking system which works effectively even when the horizon line is difficult to detect by normal thresholding methods due to flares and other effects from the presence of the sun in the image, is proposed. An algorithm for estimating the attitude from three–dimensional mapping of the horizon projected onto a 3D plane is developed. The use of optic flow to determine pitch and roll rates is investigated using the panoramic image and image interpolation algorithm (I2A). Two methods which employ sensor fusion techniques, Extended Kalman Filter (EKF) and Artificial Neural Networks (ANNs), are used to fuse unfiltered measurements from inertial sensors and the vision system. The EKF estimates gyroscope biases and also the attitude. The ANN fuses the optic flow and horizon–based attitude to provide smooth attitude estimations. The results obtained from different parts of the research are tested and validated through simulations and real flight tests.

The indoor environmental monitoring of industrial production sites is becoming increasingly important in an attempt to comply with current regulations inhering working conditions and production standards. Although monitoring tasks often consist of repetitive, time-consuming, and sometimes dangerous actions, they are mostly carried out by a human operator, who is responsible for carrying the sensor set around the working area and for enabling the communication with a remote processing system. The aim of the paper is to present the architecture of an integrated autonomous system for three-dimensional mapping of environmental conditions in indoor spaces. The proposed system integrates one (or more) autonomous guided vehicles, carrying the sensor set around the working area, a distributed wireless sensor network, providing a real-time tracking of the mobile agent, and a remote processing unit to store and elaborate the measured data. A prototype implementation of the system is herein described, in order to demonstrate the overall system feasibility.Copyright © 2010 by ASME

Anastasios John Kanellopoulos,1,2 George Asimellis1 1LaserVision.gr Eye Institute, Athens, Greece; 2Department of Ophthalmology, New York University Medical School, New York, NY, USA Purpose: To investigate epithelial thickness-distribution characteristics in a large group of keratoconic patients and their correlation to normal eyes employing anterior-segment optical coherence tomography (AS-OCT).Materials and methods: The study group (n=160 eyes) consisted of clinically diagnosed keratoconus eyes; the control group (n=160) consisted of nonkeratoconic eyes. Three separate, three-dimensional epithelial thickness maps were obtained employing AS-OCT, enabling investigation of the pupil center, average, mid-peripheral, superior, inferior, maximum, minimum, and topographic epithelial thickness variability. Intraindividual repeatability of measurements was assessed. We introduced correlation of the epithelial data via newly defined indices. The epithelial thickness indices were then correlated with two Scheimpflug imaging-derived AS-irregularity indices: the index of height decentration, and the index of surface variance highly sensitive to early and advancing keratoconus diagnosis as validation.Results: Intraindividual repeatability of epithelial thickness measurement in the keratoconic group was on average 1.67 µm. For the control group, repeatability was on average 1.13 µm. In the keratoconic group, pupil-center epithelial thickness was 51.75±7.02 µm, while maximum and minimum epithelial thickness were 63.54±8.85 µm and 40.73±8.51 µm. In the control group, epithelial thickness at the center was 52.54±3.23 µm, with maximum 55.33±3.27 µm and minimum 48.50±3.98 µm epithelial thickness. Topographic variability was 6.07±3.55 µm in the keratoconic group, while for the control group it was 1.59±0.79 µm. In keratoconus, topographic epithelial thickness change from normal, correlated tightly with the topometric asymmetry indices of IHD and ISV derived from Scheimpflug imaging.Conclusion: Simple, OCT-derived epithelial mapping, appears to have critical potential in early and advancing keratoconus diagnosis, confirmed with its correlation with established Scheimpflug-derived asymmetry topometric indices. Keywords: anterior-segment optical coherence tomography, early and advancing keratoconus, epithelial thickness imaging, novel corneal epithelial thickness-asymmetry indices, three-dimensional mapping, Scheimpflug imaging based Pentacam, topographic keratoconus grading, index of surface variance, index of height decentration

Three-dimensional maps of the distribution of coronal electron density can now be computed with two radial functions in the series expansion for the density. This report contains examples of the improved maps derived from two radial functions, and a detailed discussion of the expectations and limitations of the method.