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Since a few years, structure-from-motion and multi-view stereo pipelines have become omnipresent in the cultural heritage domain. The fact that such Image-Based Modelling (IBM) approaches are capable of providing a photo-realistic texture along the threedimensional (3D) digital surface geometry is often considered a unique selling point, certainly for those cases that aim for a visually pleasing result. However, this texture can very often also obscure the underlying geometrical details of the surface, making it very hard to assess the morphological features of the digitised artefact or scene. Instead of constantly switching between the textured and untextured version of the 3D surface model, this paper presents a new method to generate a morphology-enhanced colour texture for the 3D polymesh. The presented approach tries to overcome this switching between objects visualisations by fusing the original colour texture data with a specific depiction of the surface normals. Whether applied to the original 3D surface model or a lowresolution derivative, this newly generated texture does not solely convey the colours in a proper way but also enhances the smalland large-scale spatial and morphological features that are hard or impossible to perceive in the original textured model. In addition, the technique is very useful for low-end 3D viewers, since no additional memory and computing capacity are needed to convey relief details properly. Apart from simple visualisation purposes, the textured 3D models are now also better suited for on-surface interpretative mapping and the generation of line drawings., Please cite as: Verhoeven, G., 2017. Computer graphics meets image fusion. 26th International CIPA Symposium: Digital Workflows for Heritage Conservation, 29 August 2017, Ottawa, Canada. DOI: 10.5281/zenodo.886541

This research explains the methodology applied to the representation of the column shafts and capitals of the Temple C in the Selinunte Archaeological Site.Using mathematical auxiliary surfaces and NURBS modelling tools, textured highly-detailed meshes, produced with photogrammetry and laser scanner 3D data, was unwrapped onto a reference plane.The purpose of this unwrapping is to realize orthoimages that accurately describe the conic and toric surfaces of column shafts and echinus.Methodology gives a solution to the restoration and conservation specialists offering drawings on which to detect, map and quantify in these the damaged areas on complex curved surfaces.

Digital images play an important role in human life since they allow observing, analyzing, studying and characterizing the world surrounding us. Their use is ubiquitous in many applications such as medicine, biology, astronomy and industrial manufacture. Nonetheless, the desired digital images are often not available and need to be recovered from corrupted, incomplete and/or indirect observations. Determining the unknown image from the available observations is called an inverse problem. In this thesis, we study several inverse problems in imaging and investigate how to solve them using optimization techniques. These techniques are based on an accurate characterization of the physical model and the properties of the image of interest, making them robust to distortions in the acquisition and modeling processes. In the first part of the thesis, we consider a recent tomographic application called optical deflectometric tomography. The inverse problem investigated consists on obtaining, from noisy and incomplete observations, an accurate image describing the spatial distribution of the refractive index of a transparent object. In the second part of the thesis, the 2-D phase unwrapping problem is analyzed. This problem consists of estimating a phase image from its noisy wrapped observation. By working with a forward model in the derivative domain, the problem is relaxed and solved using convex optimization techniques. In the last part of the thesis, the blind deconvolution problem is studied in the context of astronomical imaging. In this problem, both the actual image and the sensing operator (a convolution kernel) are unknown and are simultaneously estimated from noisy observations. (FSA - Sciences de l'ingénieur) -- UCL, 2016

In this communication, we report a new method to determine the wavefront aberration function of personalized eyes. We obtain corneal surface data and axial lengths for different eyes. With these data, we construct a diffractive model of a human eye, which permits calculation of propagated light distributions at any distance inside the eye. We obtain the field at the exit of crystalline lens and extract the phase information. To unwrap this phase we use a path-following method and with the reconstructed phase we obtain the wavefront aberration function that we analyze using Zernike polynomials. The method allows linking between field patterns and wavefront surfaces that are softer and easier to analyze. To demonstrate the possibilities of the technique we have chosen five eyes which present different levels of corneal irregularities, from a quasi-spherical cornea to a very deformed one. This work has been supported by the Ministerio de Educación y Ciencia (Spain) through the project no. FIS2005-05053 and by the Conselleria de Empresa, Universitat i Ciència of the Generalitat Valencia (Valencia, Spain), through the project no. ACOMP06/099.

An important step in the interferometric processing chain is the phase unwrapping, which transforms the ambiguous phase (wrapped in the interval -/+ 180°) in an unambiguous phase. This unambiguous phase can then be used for the computation of the scene height model. Standard phase unwrapping methods work with data from a single frequency and a single baseline at a time. The unwrapping becomes extremely challenging for data with small height of ambiguity (HoA), which is usually the case when working with high frequencies and large baselines. The use of multichannel information can help to solve the ambiguities, improving the unwrapping results. However, for airborne repeat-pass InSAR data, the presence of uncompensated residual motion errors usually affects the efficiency of multibaseline approaches. For systems capable of acquiring data simultaneously in different frequency bands, as is the case of the F-SAR of DLR, multifrequency approaches can be explored to cope with the residual errors issue. In this thesis, different unwrapping algorithms are evaluated for the unwrapping of data with small height of ambiguity. Furthermore, methods to jointly unwrap interferograms from multifrequency acquisitions in a robust manner are analyzed.

In photoelasticity, the method of obtaining the individual values of principal stresses/normal stresses separately is referred to as stress separation. Shear difference is one of the widely used techniques for stress separation in photoelasticity and one needs the value of fringe order and the isoclinic angle free of noise at every pixel over the domain. For accurate parameter determination, a ten-step phase shifting approach which uses a plane polariscope for isoclinic determination and a circular polariscope for isochromatic determination is proposed. A new quality guided approach for isoclinic unwrapping is developed. Isochromatic phasemap free of ambiguous zones is obtained by a new methodology and is unwrapped by a quality-guided approach. Whole field evaluation of stress components and its representation is then presented. The models used in this study are intentionally subjected to moderate loads showing a high level of isochromatic-isoclinic interaction. In view of this, the isoclinic data has several kinks which is found to cause streak formation in the whole field representation of separated stress components. An outlier smoothing algorithm is proposed for getting a smooth variation of the digital photoelastic parameters over the domain. Use of such smoothed data for stress separation has removed the streaks and has also greatly improved the accuracy of the separated stress components. � 2007 Elsevier Ltd. All rights reserved.

In this work, the principle of interferometry is used to assess the surface roughness of the machined surfaces. Interferometry produces an interference fringe pattern when two or more light waves interact with each other. It is one of the important tool for precision optical metrology and testing. Well-known advantages of the phase shifting interferometry include high measurement accuracy, rapid measurement, good result even with low contrast fringes and that the polarity of the wave front can be determined. In fringe projection techniques, a known optical fringe pattern is projected onto the surface of interest. The fringe pattern on the surface is perturbed in accordance with the profile of the test surface, thereby enabling direct derivation of surface profile. In this work, an attempt has been made to assess the surface roughness using a speckle fringe analysis method of five frame phase shift algorithm for machined surface (ground surface). As these fringes are too noisy, advanced filtering technique has been used so as to reduce noise and to get improved wrapped phase map from the phase shifted fringes. A phase unwrapping software has been developed using discrete cosine transform (DCT) to generate the three-dimensional (3-D) profiles. Finally, it is compared with Ra values measured using a mechanical stylus instrument, showing good agreement. � 2007 Elsevier Ltd. All rights reserved.

Der industrielle Einsatz der Speckleinterferometrie zur dreidimensionalen Formvermessung wird bisher durch lange Mess- und Rechenzeiten erschwert. Um eine Echtzeitauswertung zu erreichen, werden zunächst die Phasenbildberechnung und deren anschließende Entfaltung untersucht. Dazu werden Algorithmen entwickelt und in VHDL auf FPGAs realisiert. Danach erfolgt die Modifizierung eines Speckle-Interferometers derart, dass es mit geschalteten Laserdioden ohne bewegte Verschlusseinrichtungen arbeitet. Die eingesetzten Laserdioden werden dazu direkt im System auf Stabilität und Wellenlänge vermessen, so dass diese Parameter stets bekannt sind. Im Ergebnis dient das Zwei-Wellenlängen-Speckleinterferometer zur Vermessung von dreidimensionalen Objekten mit einer Auflösung von 1280 x 1024 Pixeln und mittleren Verarbeitungsrate von 23 Bildern pro Sekunde. The operation of speckle interferometers in the case of three dimensional object measurement is a difficult task because of the long measurement and analysis duration. To realize a realtime measurement the phase calculation and unwrapping procedure are investigated. Therefore algorithms are developed and realized in VHDL on FPGAs. In the next step the mechanical shutters are replaced by switched laser diodes. To enumerate the stability and wavelength of the these laser diodes they where observed by an in system measurement. Finally the two wavelength speckle interferometer achieves a resolution of 1280 x 1024 pixels and the operating frequency is 23 images per second.

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We present, for the first time to the best of our knowledge, a phase unwrapping method based on an algorithm which makes use of Green’s first identity. This method aims at recovering the correct phase information encoded in a fringe pattern after digital holography (DH) numerical processing. DH provides a quantitative measurement of the three-dimensional surface profile of objects. The information about the profile can be obtained in principle from the phase-map. However, the measured phase-map provides the actual phase values wrapped mod.2p so that an unwrapping process is required in order to reconstruct the object profile.

The first step of the thorough examination practised on the anonymous Egyptian mummy n°90001255 from the Guimet Natural History Museum in Lyon, following the previous «scanner» survey, was the complete removal of the wrappings. There were seven superimposed layers of linen wrappings, padding and bandages. Some pieces seem to be parts of the torp sail of a small boat ; an undamaged tunic was also recovered. As for the mummy, it was that of a man, about 40 years old, with his arms placed straight along the body. The corpse had been embalmed with natron and black resin, poured when boiling and had been eviscerated through the left abdominal wall. The internal organs had been cut off and removed by means of sharp blades. New information came to light concerning surgical methods used at that time. The five canopic bundles with no bandages but soaked in resin, were present, having been put back in the chest, the abdomen and the upper part of the pelvis. The heart was in one of them. The skull had been cleaned and treated through the nose with perforations of the ethmoid bone across each nostril ; the same method was used to coat the entire walls of the cranial cavity with hot liquid resin. It had been spread afterwards by means of postural handlings also used when draining the brain. The resinous coating was the same as the one that had coated the whole body ; it was still soft in the underpart of the thick layers accumulated at the back of the corpse. The first analyses show that it was probably a mixture of vegetal oleo-resins and pitch-like resins, without any trace of bitumen. The kind of cloth wrappings and the way they were applied in layers as well as the characteristics of the mummification process correspond to previous data recorded for the period covering the IVth to the 1st century B.C. (Ptolemaic era)., La première étape de l'examen intégral de la momie égyptienne anonyme 90001255 du Musée Guimet d'Histoire Naturelle de Lyon, succédant à l'investigation préliminaire au «scanner», a comporté le démaillotage complet. Sept enveloppes successives de linceuls de lin, bourrages et bandelettes, ont été relevées. Certaines pièces d'étoffe utilisées en tampons entre les couches paraissent avoir appartenu à la voile d'une barque ; une tunique entière a été retrouvée. La momie elle-même était celle d'un homme d'environ 40 ans gisant les bras allongés le long du corps ; traité au natron et à la résine coulée à chaud, présentant partout une couleur noire brillante, le cadavre avait été éviscéré par le flanc gauche de l'abdomen, les organes internes ayant été détachés de leurs emplacements naturels à l'aide d'instruments tranchants. Des observations nouvelles ont pu être faites sur les méthodes chirurgicales antiques mises en œuvre. Les paquets canopes, au nombre de cinq, sans bandelettes et enrobés de résine, étaient présents, replacés dans le thorax, l'abdomen et le haut du bassin ; le cœur était contenu dans un des paquets. Le crâne avait été nettoyé et traité par le nez, avec perforation de l'ethmoïde depuis l'extérieur par chaque narine ; les mêmes voies d'accès avaient été empruntées pour tapisser totalement la cavité crânienne à l'aide de résine liquide introduite à chaud et répartie par manipulations posturales, également pratiquées lors du drainage de la matière cérébrale. La résine employée était identique à celle répandue sur et dans tout le corps, protégeant aussi les canopes ; le produit était parfois malléable à la partie inférieure des couches épaisses accumulées dans la zone postérieure du corps. Les premières analyses montrent qu'il doit s'agir d'un amalgame de résines et oléo-résines végétales, excluant totalement le bitume. La nature et les modes de pose des enveloppes d'étoffe, les caractéristiques de la momification observées correspondent aux attestations consignées pour la période allant du IVe au Ier siècle avant notre ère (époque ptolémaïque)., Goyon J.-C, Vergnieux Robert. C1 — Enveloppes, déroulement et premières constatations. In: Nouvelles archives du Muséum d'histoire naturelle de Lyon, tome 25, 1987. pp. 19-33.

En este trabajo se toma una referencia de una escena de la película “El Señor de los Anillos: Las dos Torres” en la que el personaje de cgi Gollum habla consigo mismo. El objetivo ha sido replicar esta escena, para ello se han buscado referentes visuales de diversas fuentes, se ha creado un storyboard y unos blueprints a partir de los cuales se ha modelado el personaje en 3D, se han utilizado técnicas de captación de movimiento corporal y facial para la animación. Se han investigado diferentes métodos de captura de movimiento y se han utilizado los que se encontraban más al alcance del estudiante. Mediante una cámara Kineckt de Xbox one y software específico se ha llevado a cabo esta tarea. Este método de captación de movimiento se encuentra dentro del grupo de captación de movimiento sin marcadores que, igual que la animación manual, requiere el uso de morphs y de sistemas de huesos. De este modo, el resultado final, es el fruto de una animación capturada y posteriormente refinada y enriquecida de manera manual. Se ha compuesto la escena que consta del escenario, el personaje, varias luces y las cámaras, mediante las cuales se ha intentado crear una narrativa audiovisual similar a la de la película original. Se han usado técnicas de render fotorrealistas con materiales de sub-surface scattering y con el motor Mental ray. Los diferentes elementos que componen la escena han sido renderizados independientemente y compuestos posteriormente en postproducción en dónde también se han aplicado los retoques de corrección de color pertinentes. Asimismo, se han sacado canales de render complementarios como pelo, luz de efecto para lograr un acabado más realista. Por último, se ha creado una entradilla en 2D para presentar el trabajo en la que se ha replicado la tipografía de la saga y se ha creado un efecto mediante partículas de descomposición en granos de arena.

A better understanding of the short term and seasonal peat surface vertical displacements (bog breathing) (Roulet 1991) initiated by changes in the water table is needed to improve spatial models of greenhouse gas emissions (Dise 2009). Synthetic Aperture Radar Interferometry (InSAR) is a promising tool for the task but accounting for relatively large peat surface displacements (Fritz 2006, Howie & Hebda 2018) may cause propagation of ambiguity errors and unreliability (Alshammari et al. 2018, Heuff & Hanssen 2021). This is usually overlooked and the absence of ground levelling data for validation is characteristic of InSAR research in peatlands (Cigna & Sowter 2017, Alshammari et al. 2018).We calculated distributed scatterer (DS) time series over 2014–2020 for Sentinel-1 relative orbits number (RON) 80 (descending) and 160 (ascending). The high frequency continuous in situ ground levelling measurements cover the snow and ice-free period of 2016 (April–October). Limited by the availability of Sentinel-1 data, 13 images from both stacks were evaluated against the levelling of a hummock plot. DS points used in the comparison were located around the plot at 125–315 m. The bog points were referenced to the stable DS points from a nearby village (4 km away) to account for atmospheric effects. InSAR line of sight deformation results were projected to vertical dimension (uLOS).Concerning only the dates when we had SAR acquisitions, the largest change relative to the maximum surface level of the period is -6.6 cm and median change -2.4 cm for RON 80, and -7.5 cm and -2.4 cm for RON 160. The maximum deviation between the uLOS and the levelling is 5.6 cm and median 2.11 cm for RON 80. For RON 160, the maximum deviation is 5.85 cm and median 2.81 cm. The Spearman correlation coefficient (rs) between the uLOS and the levelling is 0.84 for RON 80 and rs = 0.81 for RON 160 (p-value < 0.001 in both cases).To reduce the need for ambiguity resolution in the DS time series, we used relative changes between two consecutive acquisitions (baseline of 12 or 6 days) instead of accounting for the absolute change. The in situ relative surface changes between the consecutive acquisition dates of RON 80 are -2.55...2.1 cm (median -0.08 cm) and the deviation of the DS from the levelling is -1.17...1.28 cm (median 0.38 cm). For RON 160, levelling values are -0.9...3.3 cm (median -0.3 cm) and the deviation -3.06…0.81 cm (the former is -0.45 if the 12-day image pair corresponding to the change larger than the uLOS height of ambiguity is removed), median 0.23 cm. Between the levelling and DS data rs = 0.67 (p-value 0.035) and 0.77 (p-value 0.005), respectively for RON 80 and 160. Based on the in situ levelling, we demonstrated that 1) Sentinel-1 DS time series severely underestimate real surface changes over the bog and 2) despite a serious ambiguity problem, DS time series contain the useful signal because 6-day surface changes are relatively small and usually do not need ambiguity resolution.