Development of a 3D multispectral scanner

In this paper, a new technique of scanning is proposed. It is based on a stereoscopic set composed of a structured light projector and a multispectral camera. Such a set can give the 3D information of a point like a scanner but can add accurate information about the spectral reflectance of this point. This set must be calibrated before using it. It is done by two steps: the first one is the spectral characterization of the couple illuminant and camera ; the second allows geometrically calibrating the complete set. Afterwards, the image acquisition can begin. A first multispectral image of the scene is obtained without projection of structured light. Then, with a LCD projector, a luminous line scans the scene. For each line, a grey level image is acquired. The use of the geometrical calibration parameters allows the processing of the three-dimensional coordinates of the lighted points on the scene. Moreover, and it is the main goal of the proposed system, a spectral reflectance can be associated to the built points. This spectral data comes, on one hand, from the already-done spectral characterization, and, on the other hand, from the first multispectral image acquired without projection of structured light. By comparing the results issued from such a system and those from a system composed of a color camera or a color scanner, we notice that the spectrum associated to the three-dimensional points brings much more informative data than only three color components: for example, since the spectral reflectance is independent of the light used during the acquisition, the 3D scene can be easily simulated under any illuminant. This kind of simulations finds a great interest in several multimedia applications such as 3D objects visualization for virtual museums.Dans cet article, une nouvelle technique de scanning est proposée. Elle est basée sur un système stéréoscopique composé d’un projecteur de lumière structurée et d’une caméra multispectrale. Un tel système offre la possibilité de donner l’information 3D d’un point comme pour un scanner classique mais également de fournir une information précise sur le spectre de réflectance de ce point. Avant utilisation, il est nécessaire de calibrer l’ensemble. Le calibrage se déroule en deux étapes : la première d’entre elles consiste à caractériser la réponse spectrale de l’ensemble illuminant et caméra, la seconde permet de le calibrer géométriquement. A ce stade, l’analyse de la scène à reconstruire consiste, en premier lieu, en l’acquisition d’une unique image multispectrale de la scène sans projection de motif caractéristique. Ensuite, à l’aide d’un projecteur LCD, une ligne de lumière est projetée en balayage sur la scène. Pour chaque projection de ligne, une image en niveaux de gris est acquise. L’utilisation des paramètres de calibrage géométrique permet de remonter aux coordonnées tridimensionnelles des points illuminés de la scène. De plus, et c’est ici que réside l’apport principal du système proposé, un spectre de réflectance est associé à chacun des points reconstruits. Cette information spectrale provient d’une part, de la caractérisation spectrale préalablement effectuée et d’autre part, de la première image multispectrale acquise sans projection de lumière structurée. Si l’on compare les résultats obtenus avec un tel système et ceux issus d’un système composé d’une caméra couleur ou d’un scanner couleur, on remarque que le spectre associé aux points tridimensionnels apporte une information considérablement plus riche qu’un simple triplet de composantes chromatiques : par exemple, l’information spectrale étant indépendante de l’illuminant utilisé pendant l’acquisition, la scène 3D reconstruite peut être aisément simulée sous un illuminant quelconque. Ce genre de simulations trouve son intérêt dans des applications multimédias de type visualisation d’objets 3D pour des musées virtuels

The Large Hadron–Electron Collider at the HL-LHC

The Large Hadron–Electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy-recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High-Luminosity Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron–proton and proton–proton operations. This report represents an update to the LHeC's conceptual design report (CDR), published in 2012. It comprises new results on the parton structure of the proton and heavier nuclei, QCD dynamics, and electroweak and top-quark physics. It is shown how the LHeC will open a new chapter of nuclear particle physics by extending the accessible kinematic range of lepton–nucleus scattering by several orders of magnitude. Due to its enhanced luminosity and large energy and the cleanliness of the final hadronic states, the LHeC has a strong Higgs physics programme and its own discovery potential for new physics. Building on the 2012 CDR, this report contains a detailed updated design for the energy-recovery electron linac (ERL), including a new lattice, magnet and superconducting radio-frequency technology, and further components. Challenges of energy recovery are described, and the lower-energy, high-current, three-turn ERL facility, PERLE at Orsay, is presented, which uses the LHeC characteristics serving as a development facility for the design and operation of the LHeC. An updated detector design is presented corresponding to the acceptance, resolution, and calibration goals that arise from the Higgs and parton-density-function physics programmes. This paper also presents novel results for the Future Circular Collider in electron–hadron (FCC-eh) mode, which utilises the same ERL technology to further extend the reach of DIS to even higher centre-of-mass energies