Search results for "Libration"

Spectral Characterization of a Prototype SFA Camera for Joint Visible and NIR Acquisition

2016

International audience; Multispectral acquisition improves machine vision since it permits capturing more information on object surface properties than color imaging. The concept of spectral filter arrays has been developed recently and allows multispectral single shot acquisition with a compact camera design. Due to filter manufacturing difficulties, there was, up to recently, no system available for a large span of spectrum, i.e., visible and Near Infra-Red acquisition. This article presents the achievement of a prototype of camera that captures seven visible and one near infra-red bands on the same sensor chip. A calibration is proposed to characterize the sensor, and images are captured…

Application of the Morris method for screening the influential parameters of fuzzy controllers applied to wastewater treatment plants

2011

In this paper,we evaluate the application of a sensitivity analysis to help fine-tuning a fuzzy controller for a biological nitrogen and phosphorus removal (BNPR) plant. TheMorris Screeningmethod is proposed and evaluated as a prior step to obtain the parameter significance ranking. First, an iterative procedure has been performed in order to find out the proper repetition number of the elementary effects (r) of the method. The optimal repetition number found in this study (r = 60) is in direct contrast to previous applications of the Morris method, which usually use low repetition number, e.g. r = 10 ~ 20. Working with a non-proper repetition number (r) could lead to Type I error (identify…

2014

A 3D imaging technique using a high speed binocular stereovision system was developed in combination with corresponding image processing algorithms for accurate determination of the parameters of particles leaving the spinning disks of centrifugal fertilizer spreaders. Validation of the stereo-matching algorithm using a virtual 3D stereovision simulator indicated an error of less than 2 pixels for 90% of the particles. The setup was validated using the cylindrical spread pattern of an experimental spreader. A 2D correlation coefficient of 90% and a Relative Error of 27% was found between the experimental results and the (simulated) spread pattern obtained with the developed setup. In combin…

Increasing the accuracy of untaught robot positions by means of a multi-camera system

2010

We aim to improve the absolute in line positional accuracy of a robot-guided effector to better than 1 mm. We do so using photogrammetric techniques and by relying heavily on simulations to fine tune each parameter and avoid weak configurations. We also use simulations to design an LED calibration object adapted to this application. A test procedure enables us to validate both the simulated results as well as the calibration procedure. The test results exceed expectations by improving the absolute positioning of a robot effector by a factor of 20.

Uncertainty assessment of a model for biological nitrogen and phosphorus removal: Application to a large wastewater treatment plant

2012

Abstract In the last few years, the use of mathematical models in WasteWater Treatment Plant (WWTP) processes has become a common way to predict WWTP behaviour. However, mathematical models generally demand advanced input for their implementation that must be evaluated by an extensive data-gathering campaign, which cannot always be carried out. This fact, together with the intrinsic complexity of the model structure, leads to model results that may be very uncertain. Quantification of the uncertainty is imperative. However, despite the importance of uncertainty quantification, only few studies have been carried out in the wastewater treatment field, and those studies only included a few of …

The identifiability analysis for setting up measuring campaigns in integrated water quality modelling.

2012

Abstract Identifiability analysis enables the quantification of the number of model parameters that can be assessed by calibration with respect to a data set. Such a methodology is based on the appraisal of sensitivity coefficients of the model parameters by means of Monte Carlo runs. By employing the Fisher Information Matrix, the methodology enables one to gain insights with respect to the number of model parameters that can be reliably assessed. The paper presents a study where identifiability analysis is used as a tool for setting up measuring campaigns for integrated water quality modelling. Particularly, by means of the identifiability analysis, the information about the location and …

A robust calibration methodology for an On-Board Diagnostic car system

2006

New car models are now by law equipped with on-board diagnostic (OBD) systems aimed at monitoring the state of health of strategic components that ensure low levels of polluting exhaust emissions. During development phases, for each new car model, the OBD system must be finely calibrated. This article presents a robust calibration methodology taking into account sources of variability mainly due to production process, operating, and environmental conditions. The methodology enables us to evaluate the false alarm and failure to detect risks intrinsically related to the adopted calibration. An application concerning an upstream oxygen sensor monitored by the OBD is presented.

A New Method to Measure 3D Textile Defects by Using Dual-lens Camera

2013

International audience; Industrial textile fabric with functionalization always has a high standard requirement. Take polytetrafluoroethylene (PTFE) conveyor belt as an example, the base fabrics must be of first-rate quality, with no weaving faults or broken fibers on coated surface [1]. In a previous work, we have proposed an original method to measure the height of the fiber based on variable homography. This measurement is based on a single camera acquiring two successive frames. This scheme is working well, but measurement depends on conveyor speed used for scrolling fabric. In this paper, we propose an improvement by using a new acquisition device based on two mini-lenses assembled as …

A Multi-Position Calibration Method for Consumer-Grade Accelerometers, Gyroscopes, and Magnetometers to Field Conditions

2017

This paper presents a calibration method for consumer-grade accelerometers, gyroscopes, and magnetometers. Considering the calibration of consumer-grade sensors, it is essential that no specialized equipment is required to create reference signals. In addition, the less is required from the reference signals, the more suitable the method is on the field. In the proposed method, the novelty in the calibration of the gyroscopes lies in the exploitation of only the known net rotations between the positions in a multi-position calibration. For accelerometers and magnetometers, the innovation is that the direction of reference signals, the gravity and the magnetic field of the Earth, are estimat…

Energy Savings through Integration of the Illumination Natural and Artificial, Using a System of Automatic Dimming: Case Study

2013

The reduction of electrical energy consumption in buildings is a subject of great interest in the international scientific community. In buildings with a lot of available natural light, designed with large glazed surfaces, the artificial lighting system is often oversized and cannot be divided into segments to meet lighting demands during daylight hours.This article presents an experimental study, conducted in a university lecture hall that has a glazed surface covering the whole wall at one end, which provides a level of internal illumination that is only sufficient for the area next to the window itself, even when the outside lighting conditions are very bright. It is therefore necessary …