Pareto optimality solution of the multi-objective photogrammetric resection-intersection problem

Reconstruction of architectural structures from photographs has recently experienced intensive efforts in computer vision research. This is achieved through the solution of nonlinear least squares (NLS) problems to obtain accurate structure and motion estimates. In Photogrammetry, NLS contribute to the determination of the 3-dimensional (3D) terrain models from the images taken from photographs. The traditional NLS approach for solving the resection-intersection problem based on implicit formulation on the one hand suffers from the lack of provision by which the involved variables can be weighted. On the other hand, incorporation of explicit formulation expresses the objectives to be minimized in different forms, thus resulting in different parametric values for the estimated parameters at non-zero residuals. Sometimes, these objectives may conflict in a Pareto sense, namely, a small change in the parameters results in the increase of one objective and a decrease of the other, as is often the case in multi-objective problems. Such is often the case with error-in-all-variable (EIV) models, e.g., in the resection-intersection problem where such change in the parameters could be caused by errors in both image and reference coordinates.This study proposes the Pareto optimal approach as a possible improvement to the solution of the resection-intersection problem, where it provides simultaneous estimation of the coordinates and orientation parameters of the cameras in a two or multistation camera system on the basis of a properly weighted multi-objective function. This objective represents the weighted sum of the square of the direct explicit differences of the measured and computed ground as well as the image coordinates. The effectiveness of the proposed method is demonstrated by two camera calibration problems, where the internal and external orientation parameters are estimated on the basis of the collinearity equations, employing the data of a Manhattan-type test field as well as the data of an outdoor, real case experiment. In addition, an architectural structural reconstruction of the Merton college court in Oxford (UK) via estimation of camera matrices is also presented. Although these two problems are different, where the first case considers the error reduction of the image and spatial coordinates, while the second case considers the precision of the space coordinates, the Pareto optimality can handle both problems in a general and flexible way

Full Counting Statistics of a Superconducting Beam Splitter

We study the statistics of charge transport in a mesoscopic three-terminal device with one superconducting terminal and two normal-metal terminals. We calculate the full distribution of transmitted charges into the two symmetrically biased normal terminals. In a wide parameter range, we find large positive crosscorrelations between the currents in the two normal arms. We also determine the third cumulant that provides additional information on the statistics not contained in the current noise.Comment: 5 pages, 2 figures, revtex

Energy dependent counting statistics in diffusive superconducting tunnel junctions

We present an investigation of the energy dependence of the full charge counting statistics in diffusive normal-insulating-normal-insulating-superconducting junctions. It is found that the current in general is transported via a correlated transfer of pairs of electrons. Only in the case of strongly asymmetric tunnel barriers or energies much larger than the Thouless energy is the pair transfer uncorrelated. The second cumulant, the noise, is found to depend strongly on the applied voltage and temperature. For a junction resistance dominated by the tunnel barrier to the normal reservoir, the differential shot noise shows a double peak feature at voltages of the order of the Thouless energy, a signature of an ensemble averaged electron-hole resonance.Comment: 8 pages, 5 figure

MODULAR BUNDLE ADJUSTMENT FOR PHOTOGRAMMETRIC COMPUTATIONS

In this paper we investigate how the residuals in bundle adjustment can be split into a composition of simple functions. According to the chain rule, the Jacobian (linearisation) of the residual can be formed as a product of the Jacobians of the individual steps. When implemented, this enables a modularisation of the computation of the bundle adjustment residuals and Jacobians where each component has limited responsibility. This enables simple replacement of components to e.g. implement different projection or rotation models by exchanging a module. The technique has previously been used to implement bundle adjustment in the open-source package DBAT (Börlin and Grussenmeyer, 2013) based on the Photogrammetric and Computer Vision interpretations of Brown (1971) lens distortion model. In this paper, we applied the technique to investigate how affine distortions can be used to model the projection of a tilt-shift lens. Two extended distortion models were implemented to test the hypothesis that the ordering of the affine and lens distortion steps can be changed to reduce the size of the residuals of a tilt-shift lens calibration. Results on synthetic data confirm that the ordering of the affine and lens distortion steps matter and is detectable by DBAT. However, when applied to a real camera calibration data set of a tilt-shift lens, no difference between the extended models was seen. This suggests that the tested hypothesis is false and that other effects need to be modelled to better explain the projection. The relatively low implementation effort that was needed to generate the models suggest that the technique can be used to investigate other novel projection models in photogrammetry, including modelling changes in the 3D geometry to better understand the tilt-shift lens

Improving Underwater Accuracy by Empirical Weighting of Image Observations

An underwater imaging system with camera and lens behind a flat port does not behave as a standard pinhole camera with additional parameters. Indeed, whenever the entrance pupil of the lens is not in contact with the flat port, the standard photogrammetric model is not suited anymore and an extended mathematical model that considers the different media would be required. Therefore, when dealing with flat ports, the use of the classic photogrammetric formulation represents a simplification of the image formation phenomenon, clearly causing a degradation in accuracy. Furthermore, flat ports significantly change the characteristics of the enclosed imaging device and negatively affect the image quality, introducing heavy curvilinear distortions and optical aberrations. With the aim of mitigating the effect of systematic errors introduced by a combination of (i) image quality degradation, induced by the flat ports, and (ii) a non-rigorous modelling of refraction, this paper presents a stochastic model for image observations that penalises those that are more affected by aberrations and departure from the pinhole model. Experiments were carried out at sea and in pools showing that the use of the proposed stochastic model is beneficial for the final accuracy with improvements up to 50 %

Des outils pour fiabiliser les fermentations des vins et cidres biologiques en utilisant les levures et bactéries indigènes

Ce numéro comprend les articles correspondant aux présentations du Colloque Casdar 2018.With the development of organic wines and ciders, there is a real tendency to carry out spontaneousfermentations, which involve the development of indigenous yeasts and bacteria. Indeed, thesemicroorganisms are sometimes considered as components of the terroir that participate in the typicity ofwines and ciders. However, no scientific knowledge allows us to assert such a specificity, while the lackof control of these microorganisms can lead to difficulties of fermentation, aromatic deviations oralterations. The project CASDAR Levains Bio relied on a network of laboratories, technical institutes andassociations of organic producers to provide the necessary knowledge and practical solutions forcarrying out indigenous fermentations with a good level of control. It has been shown that there is awide diversity of strains of the yeast Saccharomyces cerevisiae and the lactic acid bacteriumOenococcus oeni, that strains are genetically adapted to certain products, but not to regions orproduction sites. Protocols have been developed to allow for the selection of strains from farms or forthe production of "pieds de cuve". Some of the solutions have been successfully transferred toproducers.Avec le développement des vins et cidres bio, on observe une vraie tendance à la réalisation defermentations spontanées, en laissant se développer les levures et bactéries indigènes. En effet, cesmicroorganismes sont parfois considérés comme des éléments du terroir qui participent à la typicité desvins et des cidres. Pourtant, aucune connaissance scientifique ne permet d’affirmer une telle spécificité,alors que la non-maîtrise de ces microorganismes peut conduire à des difficultés de fermentation, desdéviations aromatiques ou des altérations. Le projet Casdar Levains Bio s’est appuyé sur un réseau delaboratoires, instituts techniques et associations de producteurs bio pour apporter les connaissancesnécessaires et des solutions pratiques pour réaliser des fermentations indigènes avec un bon niveau demaîtrise. Il a été montré qu’il existe une grande diversité de souches de la levure Saccharomycescerevisiae et de la bactérie lactique Oenococcus oeni, que des souches sont génétiquement adaptées àcertains produits, mais pas à des régions ou à des sites de production. Des protocoles ont été mis aupoint pour permettre de sélectionner des souches issues des exploitations ou pour réaliser des pieds decuve de microorganismes indigènes. Certaines des solutions ont été transférées avec succès auprèsdes producteurs

Innov. agron.

Avec le développement des vins et cidres bio, on observe une vraie tendance à la réalisation de fermentations spontanées, en laissant se développer les levures et bactéries indigènes. En effet, ces microorganismes sont parfois considérés comme des éléments du terroir qui participent à la typicité des vins et des cidres. Pourtant, aucune connaissance scientifique ne permet d’affirmer une telle spécificité, alors que la non-maîtrise de ces microorganismes peut conduire à des difficultés de fermentation, des déviations aromatiques ou des altérations. Le projet Casdar Levains Bio s’est appuyé sur un réseau de laboratoires, instituts techniques et associations de producteurs bio pour apporter les connaissances nécessaires et des solutions pratiques pour réaliser des fermentations indigènes avec un bon niveau de maîtrise. Il a été montré qu’il existe une grande diversité de souches de la levure Saccharomyces cerevisiae et de la bactérie lactique Oenococcus oeni, que des souches sont génétiquement adaptées à certains produits, mais pas à des régions ou à des sites de production. Des protocoles ont été mis au point pour permettre de sélectionner des souches issues des exploitations ou pour réaliser des pieds de cuve de microorganismes indigènes. Certaines des solutions ont été transférées avec succès auprès des producteurs. | With the development of organic wines and ciders, there is a real tendency to carry out spontaneous fermentations, which involve the development of indigenous yeasts and bacteria. Indeed, these microorganisms are sometimes considered as components of the terroir that participate in the typicity of wines and ciders. However, no scientific knowledge allows us to assert such a specificity, while the lack[br/] of control of these microorganisms can lead to difficulties of fermentation, aromatic deviations or alterations. The project CASDAR Levains Bio relied on a network of laboratories, technical institutes and associations of organic producers to provide the necessary knowledge and practical solutions for carrying out indigenous fermentations with a good level of control. It has been shown that there is a wide diversity of strains of the yeast Saccharomyces cerevisiae and the lactic acid bacterium Oenococcus oeni, that strains are genetically adapted to certain products, but not to regions or production sites. Protocols have been developed to allow for the selection of strains from farms or for the production of "pieds de cuve". Some of the solutions have been successfully transferred to producers