2D qualitative shape matching applied to ceramic mosaic assembly

A theory of shape recognition of 2D objects and its application in the ceramic industry for intelligent automation of the mosaic mural assembly process are presented in this paper. This theory qualitatively describes the shapes of the objects, considering: (i) shape boundary characteristics, such as angles, relative length, concavities, and curvature; and (ii) their color and size. The shapes to be recognized may be regular or irregular closed polygons, or closed curvilinear figures. Each figure is described as a symbolic character string that contains all its distinctive characteristics. This description is used to determine whether the shape of two figures matches. Then, given a design of a mosaic and given a set of physical ceramic tesserae, an application is developed in order to recognize the tesserae that form the mosaic, thus enabling the intelligent and automated assembly of ceramic mosaics

Measures of Similarity between Qualitative Descriptions of Shape, Colour and Size Applied to Mosaic Assembling

A computational approach for obtaining a similarity measure between qualitative descriptions of shape, colour and size of objects within digital images is presented. According to the definition of the qualitative features, the similarity values determined are based on conceptual neighbourhood diagrams or interval distances. An approximate matching algorithm between object descriptions is defined and applied to tile mosaic assembling and results of previous approaches are improved.This work has been partially supported by Universitat Jaume I (Fons del Pla Estratégic de 2011/2012), by the Zentrale Forschungsförderung der Universität Bremen under the project name “Providing human-understandable qualitative and semantic descriptions”, and by the Spanish Ministry of Science and Innovation under project ARTEMISA (TIN2009-14378-C02-01)

A Pragmatic Qualitative Approach for Juxtaposing Shapes

This paper presents a qualitative shape description scheme which has been defined in order to have a formal theory to allow the construction of new shapes from a set of given shapes by using a juxtaposition operation. Specifically, the qualitative shape description scheme defined is a pragmatic scheme since it has been defined in order to be applied in the automatic and intelligent assembling of trencadís mosaic

Measures of Similarity Between Objects Based on Qualitative Shape Descriptions

A computational approach for comparing qualitative shape descriptions (QSDs) of objects within digital images is presented. First, the dissimilarity of qualitative features of shape is measured: (i) intuitively using conceptual neighbourhood diagrams; and (ii) mathematically using interval distances. Then, a similarity measure between QSDs is defined and tested using images of different categories of the MPEG-7-CE-Shape-1 library, images of tiles used to build mosaics, and a collection of Clipart images. The results obtained show the effectiveness of the similarity measure defined, which is invariant to translations, rotations and scaling, and which implicitly manages deformation of shape parts and incompleteness

Qualitative Distances and Qualitative Description of Images for Indoor Scene Description and Recognition in Robotics

The automatic extraction of knowledge from the world by a robotic system as human beings interpret their environment through their senses is still an unsolved task in Artificial Intelligence. A robotic agent is in contact with the world through its sensors and other electronic components which obtain and process mainly numerical information. Sonar, infrared and laser sensors obtain distance information. Webcams obtain digital images that are represented internally as matrices of red, blue and green (RGB) colour coordinate values. All this numerical values obtained from the environment need a later interpretation in order to provide the knowledge required by the robotic agent in order to carry out a task. Similarly, light wavelengths with specific amplitude are captured by cone cells of human eyes obtaining also stimulus without meaning. However, the information that human beings can describe and remember from what they see is expressed using words, that is qualitatively. The research work done in this thesis tries to narrow the gap between the acquisition of low level information by robot sensors and the need of obtaining high level or qualitative information for enhancing human-machine communication and for applying logical reasoning processes based on concepts. Moreover, qualitative concepts can be added a meaning by relating them to others. They can be used for reasoning applying qualitative models that have been developed in the last twenty years for describing and interpreting metrical and mathematical concepts such as orientation, distance, velocity, acceleration, and so on. And they can be also understood by human-users both written and read aloud. The first contribution presented is the definition of a method for obtaining fuzzy distance patterns (which include qualitative distances such as near , far , very far and so on) from the data obtained by any kind of distance sensors incorporated in a mobile robot and the definition of a factor to measure the dissimilarity between those fuzzy patterns. Both have been applied to the integration of the distances obtained by the sonar and laser distance sensors incorporated in a Pioneer 2 dx mobile robot and, as a result, special obstacles have been detected as glass window , mirror , and so on. Moreover, the fuzzy distance patterns provided have been also defuzzified in order to obtain a smooth robot speed and used to classify orientation reference systems into open (it defines an open space to be explored) or closed . The second contribution presented is the definition of a model for qualitative image description (QID) based on qualitative models of shape, colour, topology and orientation. This model can qualitatively describe any kind of digital image and is independent of the image segmentation method used. The QID model have been tested in two scenarios in robotics: (i) the description of digital images captured by the camera of a Pioneer 2 dx mobile robot and (ii) the description of digital images of tile mosaics taken by an industrial camera located on a platform used by a robot arm to assemble tile mosaics. In order to provide a formal and explicit meaning to the qualitative description of the images generated, a Description Logic (DL) based ontology has been designed and presented as the third contribution. Our approach can automatically process any random image and obtain a set of DL-axioms that describe it visually and spatially. And objects included in the images are classified according to the ontology schema using a DL reasoner. Tests have been carried out using digital images captured by a webcam incorporated in a Pioneer 2 dx mobile robot. The images taken correspond to the corridors of a building at University Jaume I and objects with them have been classified into walls , floor , office doors and fire extinguishers under different illumination conditions and from different observer viewpoints. The final contribution is the definition of a similarity measure between qualitative descriptions of shape, colour, topology and orientation. And the integration of those measures into the definition of a general similarity measure between two qualitative descriptions of images. These similarity measures have been applied to: (i) extract objects with similar shapes from the MPEG7 CE Shape-1 library; (ii) assemble tile mosaics by qualitative shape and colour similarity matching; (iii) compare images of tile compositions; and (iv) compare images of natural landmarks in a mobile robot world for their recognition

Optimising additive manufacturing for fine art sculpture and digital restoration of archaeological artefacts

Additive manufacturing (AM) has shown itself to be beneficial in many application areas, including product design and manufacture, medical models and prosthetics, architectural modelling and artistic endeavours. For some of these applications, coupling AM with reverse engineering (RE) enables the utilisation of data from existing 3D shapes. This thesis describes the application of AM and RE within sculpture manufacture, in order to optimise the process chains for sculpture reproduction and relic conservation and restoration. This area poses particular problems since the original artefacts can often be fragile and inaccessible, and the finishing required on the AM replicas is both complex and varied. Several case studies within both literature and practical projects are presented, which cover essential knowledge of producing large scale sculptures from an original models as well as a wide range of artefact shapes and downstream finishing techniques. The combination of digital technologies and traditional art requires interdisciplinary knowledge across engineering and fine art. Also, definitions and requirements (e.g. ‘accuracy’), can be applied as both engineering and artistic terms when specifications and trade-offs are being considered. The thesis discusses the feasibility for using these technologies across domains, and explores the potential for developing new market opportunities for AM. It presents and analyses a number of case study projects undertaken by the author with a view to developing cost and time models for various processes used. These models have then been used to develop a series of "process maps", which enable users of AM in this area to decide upon the optimum process route to follow, under various circumstances. The maps were validated and user feedback obtained through the execution of two further sculpture manufacturing projects. The thesis finishes with conclusions about the feasibility of the approach, its constraints, the pros and cons of adopting AM in this area and recommendations for future research

A Technical Study and Conservation Proposal for the Glass Mosaic Decoration of Villa Caparra in Guaynabo, Puerto Rico

This thesis examines the exuberant cement-embedded glass mosaic ornamentation of Villa Caparra, an early architect’s residence in Guaynabo, Puerto Rico in order to document the materials, methods of fabrication and installation; and, to analyze the present condition. The study will rely on archival records, in situ investigation, material analysis and physical testing with the purpose of developing a preliminary conservation plan for remedial and long term preservation

Growth and characterization of epitaxially aligned titanium nitride thin films on silicon by orthogonally crossed-beam pulsed laser deposition

TiN thin films have been grown epitaxially on Si(111) substrates by crossing orthogonally a pulsed molecular N2 jet with a pulsed-laser generated Ti plume. This so- called reactive crossed-beam pulsed laser deposition technique was demonstrated as a modification of conventional pulsed laser deposition and was used to grow high quality binary compound materials. Time-of-flight (TOF) measurements of species impinging onto the substrate were performed using an in-situ ion probe, and these measurements were used to optimize the growth conditions. Average plume kinetic energies ranged from 45 to 155 eV. Under essentially fixed N2 jet conditions, the crystallographic quality of the films was found to be a stronger function of kinetic energy than growth temperature, with optimal films resulting for a plume mean kinetic energy of ~ 92 eV and substrate temperatures near 750 °C. Scattering processes within the interaction regime were explained by Singh\u27s model and it was determined that the processes between the laser plume and the pulsed gas expansion were responsible for the enhanced reactivity in crossed-beam PLD. Film-growth mechanisms and microstructure were investigated using in-situ reflection high energy electron diffraction (RHEED), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and scanning transmission electron microscopy (STEM). It was found that TiN thin films grow essentially in a Stranski-Krastanov growth mode under optimal growth conditions. Although TiN is highly mismatched with respect to Si (lattice constant mismatch of 22.3%), single crystal TiN/Si heterostructures are entirely feasible through a process known as domain-matching epitaxy. The epitaxial relationship between TiN and Si by domain-matching epitaxy is discussed in detail in this thesis. The crystalline quality and electrical properties of the films were investigated using X-ray diffraction and four-point Van der Pauw measurements, respectively. Films grown under optimal conditions were highly textured and had mosaic spreads of ~18 arc- min and ~26 arc-min for a rocking curve around the TiN(111) pole and a ø-scan through the TiN(002) pole, respectively. All the films showed metallic behavior with resistivities that varied linearly with temperature above 75 K. The best film had a room temperature resistivity of 3.76 µ2-cm. Implications of low-resistivity epitaxial TiN/Si heterostructure device fabrication are discussed. Full-Potential Linearized Augmented Plane Wave (FLAPW) density functional theory (DFT) calculations, as implemented in the WIEN97 codes, have been employed to compare experimental electron energy loss spectroscopy (EELS) results with theoretical calculations since the cross section of electron near-edge structure (ELNES) is proportional to the unoccupied density of states. The implications of these results are discussed

Effective and Efficient Non-Destructive Testing of Large and Complex Shaped Aircraft Structures

The main aim of the research described within this thesis is to develop methodologies that enhance the defect detection capabilities of nondestructive testing (NDT) for the aircraft industry. Modem aircraft non-destructive testing requires the detection of small defects in large complex shaped components. Research has therefore focused on the limitations of ultrasonic, radioscopic and shearographic methods and the complimentary aspects associated with each method. The work has identified many parameters that have significant effect on successful defect detection and has developed methods for assessing NDT systems capabilities by noise analysis, excitation performance and error contributions attributed to the positioning of sensors. The work has resulted in 1. The demonstration that positional accuracy when ultrasonic testing has a significant effect on defect detection and a method to measure positional accuracy by evaluating the compensation required in a ten axis scanning system has revealed limitsio the achievable defect detection when using complex geometry scanning systems. 2. A method to reliably detect 15 micron voids in a diffusion bonded joint at ultrasonic frequencies of 20 MHz and above by optimising transducer excitation, focussing and normalisation. 3. A method of determining the minimum detectable ultrasonic attenuation variation by plotting the measuring error when calibrating the alignment of a ten axis scanning system. 4. A new formula for the calculation of the optimum magnification for digital radiography. The formula is applicable for focal spot sizes less than 0.1 mm. 5. A practical method of measuring the detection capabilities of a digital radiographic system by calculating the modulation transfer function and the noise power spectrum from a reference image. 6. The practical application of digital radiography to the inspection of super plastically formed ditThsion bonded titanium (SPFDB) and carbon fibre composite structure has been demonstrated but has also been supported by quantitative measurement of the imaging systems capabilities. 7. A method of integrating all the modules of the shearography system that provides significant improvement in the minimum defect detection capability for which a patent has been granted. 8. The matching of the applied stress to the data capture and processing during a shearographic inspection which again contributes significantly to the defect detection capability. 9. The testing and validation of the Parker and Salter [1999] temporal unwrapping and laser illumination work has led to the realisation that producing a pressure drop that would result in a linear change in surface deformation over time is difficult to achieve. 10. The defect detection capabilities achievable by thermal stressing during a shearographic inspection have been discovered by applying the pressure drop algorithms to a thermally stressed part. 11. The minimum surface displacement measurable by a shearography system and therefore the defect detection capabilities can be determined by analysing the signal to noise ratio of a transition from a black (poor reflecting surface) to white (good reflecting surface). The quantisation range for the signal to noise ratio is then used in the Hung [1982] formula to calculate the minimum displacement. Many of the research aspects contained within this thesis are cuffently being implemented within the production inspection process at BAE Samlesbury