Search results for "Odometry"
showing 10 items of 13 documents
Selective visual odometry for accurate AUV localization
2015
In this paper we present a stereo visual odometry system developed for autonomous underwater vehicle localization tasks. The main idea is to make use of only highly reliable data in the estimation process, employing a robust keypoint tracking approach and an effective keyframe selection strategy, so that camera movements are estimated with high accuracy even for long paths. Furthermore, in order to limit the drift error, camera pose estimation is referred to the last keyframe, selected by analyzing the feature temporal flow. The proposed system was tested on the KITTI evaluation framework and on the New Tsukuba stereo dataset to assess its effectiveness on long tracks and different illumina…
Accurate keyframe selection and keypoint tracking for robust visual odometry
2016
This paper presents a novel stereo visual odometry (VO) framework based on structure from motion, where a robust keypoint tracking and matching is combined with an effective keyframe selection strategy. In order to track and find correct feature correspondences a robust loop chain matching scheme on two consecutive stereo pairs is introduced. Keyframe selection is based on the proportion of features with high temporal disparity. This criterion relies on the observation that the error in the pose estimation propagates from the uncertainty of 3D points—higher for distant points, that have low 2D motion. Comparative results based on three VO datasets show that the proposed solution is remarkab…
Investigating prismatic adaptation effects in handgrip strength and in plantar pressure in healthy subjects.
2020
Abstract Background Prismatic Adaptation (PA) is a visuomotor procedure inducing a shift of the visual field that has been shown to modulate activation of a number of brain areas, in posterior (i.e. parietal cortex) and anterior regions (i.e. frontal cortex). This neuromodulation could be useful to study neural mechanisms associated with either postural measures such as the distribution of plantar pressure or to the generation of muscle strength. Indeed, plantar pressure distribution is associated to activation of high-level cognitive mechanisms taking place within the posterior regions of the brain dorsal stream, especially of the right hemisphere. Conversely, hand force mostly rely on sen…
Use of the electronic baropodometer (EBP) to study dysmetria of the lower limbs: A case report
2001
An electronic baropodometer was used to study a case of lower limb dysmetria caused by an accident with delayed functional recovery of gait. A static baropodometric test of the patient without shoes and without orthesis revealed plantar imprints with loads within the norm; a static test with shoes but without orthesis showed that the operated right foot carried 42% of the body weight and the pressure peak M was on the second left metatarsal head, while the pressure centres of the individual plantar ("articular") imprints were not equidistant from the ground projection of the body's centre of gravity. In a static baropodometric test with shoes and with external orthesis, the loads were unifo…
Comparison of several methods used for the determination of cephalosporins. Analysis of cephalexin in pharmaceutical samples
2002
The precision of UV absorbance of intact and acid degraded cephalosporins, ninhydrin, high performance liquid chromatography and iodometric methods used for analysis of cefoxitin, cefotaxime, cephazolin and cephalexin were compared. To obtain the calibration graphs the analytical signal used were: absorbance, first derivative absorbance, second derivative absorbance and H-point Standard Additions Method by using absorbance values at two selected wavelengths as analytical signal. These methods and calibration graphs were also used for the determination of cephalexin in pharmaceutical samples.
Asynchronous sensor fusion of GPS, IMU and CAN-based odometry for heavy-duty vehicles
2021
[EN] In heavy-duty vehicles, multiple signals are available to estimate the vehicle's kinematics, such as Inertial Measurement Unit (IMU), Global Positioning System (GPS) and linear and angular speed readings from wheel tachometers on the internal Controller Area Network (CAN). These signals have different noise variance, bandwidth and sampling rate (being the latter, possibly, irregular). In this paper we present a non-linear sensor fusion algorithm allowing asynchronous sampling and non-causal smoothing. It is applied to achieve accuracy improvements when incorporating odometry measurements from CAN bus to standard GPS+IMU kinematic estimation, as well as the robustness against missing da…
A clean method for flow injection spectrophotometric determination of cyclamate in table sweeteners
2005
Abstract A flow system based on the multicommutation is proposed for fast and clean determination of cyclamate. The procedure exploits the reaction of cyclamate with nitrite in acidic medium and the spectrophotometric determination of the excess of nitrite by iodometry. The flow system was designed with a set of solenoid micro-pumps to minimize reagent consumption and waste generation. The detection limit was estimated as 30 μmol L −1 (99.7% confidence level) with linear response ranging up to 3.0 mmol L −1 . The coefficient of variation was estimated as 1.7% for a solution containing 2.0 mmol L −1 cyclamate ( n = 20). About 60 samples can be analyzed per hour, consuming only 3 mg KI and 1…
Über eine neue Methode zum Nachweis des als Primärprodukt der Autoxydation der Metalle Eisen, Nickel und Kobalt in Säure- und Salzlösungen gebildeten…
1971
H2O2 als Zwischenprodukt der Autoxydation (bzw. · OOH oder · OH) kann mit Hilfe der Phosphin-, Phosphinoxid- Methode bei Fe, Ni und Co wirksamer als mit Hilfe der Jodometrie erfast werden. In saurem Medium sind Tris-(m-aminophenyl)-phosphin (1), im alkalischen Bereich Tris-(p-carboxyphenyl)- phosphin (2) wirksame auch fur quantitative Bestimmungen geeignete Reagentien auf H2O2 · 1 und 2 reagieren bei hoheren Konzentrationen bis zu 20 ma1 schneller mit H2O2 als dieses mit der Eisengrenzflache. Ni und Co erzeugen mehr H2O2 als Fe. Bei Eisen entsteht im neutralen Medium mehr H2O2 als im sauren Bereich. Die unterschiedlichen Anfangsgeschwindigkeiten des Sauerstoffverbrauchs in sauerstoffhaltige…
2D-3D Camera Fusion for Visual Odometry in Outdoor Environments
2014
International audience; Accurate estimation of camera motion is very important for many robotics applications involving SfM and visual SLAM. Such accuracy is attempted by refining the estimated motion through nonlinear optimization. As many modern robots are equipped with both 2D and 3D cameras, it is both highly desirable and challenging to exploit data acquired from both modalities to achieve a better localization. Existing refinement methods, such as Bundle adjustment and loop closing, may be employed only when precise 2D-to-3D correspondences across frames are available. In this paper, we propose a framework for robot localization that benefits from both 2D and 3D information without re…
How do sports affect static baropodometry? An observational study among women living in southern Italy
2018
Purpose. the aim of the study was (a) to investigate the differences in plantar pressure distribution between athletes (A) and sedentary (S) women; (b) to examine the differences, if any, in plantar pressure between sports within the A group. Methods. the study involved 173 females; 98 were S (age: 24.23 ± 6.11 years; height: 161.11 ± 6.44 cm; weight: 56.70 ± 8.19 kg; bMI: 21.81 ± 2.52 kg/m 2 ; body surface area [bSA]: 1.59 ± 0.13; shoe size: 37.83 ± 1.53), 75 were A (age: 22.47 ± 4.89 years; height: 159.98 ± 5.95 cm; weight: 55.49 ± 7.61 kg; bMI: 21.62 ± 2.18 kg/m 2 ; bSA: 1.57 ± 0.12; shoe size: 38.05 ± 1.55). For plantar support analysis, the FreeMed posturography system was used, includ…