View Synthesizing for a Large-Scale Object in a Scene

A robust method for panorama view reconstruction of a scene is presented. The images of a scene are acquired by moving a camera to multiple viewpoints. We present a robust method of panorama synthesizing based on image mosaicing approach. The edge detection and feature points extraction are performed for each image. The corresponding feature points between two successive images are estimated and the between these images is computed. These two images are integrated based on the different of minimum threshold values between them. After that, the full-view of a scene is reconstructed by merging the successive integrated images by developed image mosaicing approach. This research describes how to establish feature correspondences between images accurately and effectively. Image registration technique provides an initial estimation for establishing feature correspondences of point features. The linear solution with the reliable correspondences makes the computation of the geometric transformation between two images

3DMADMAC|AUTOMATED: synergistic hardware and software solution for automated 3D digitization of cultural heritage objects

In this article a fully automated 3D shape measurement system and data processing algorithms are presented. Main purpose of this system is to automatically (without any user intervention) and rapidly (at least ten times faster than manual measurement) digitize whole object’s surface with some limitations to its properties: maximum measurement volume is described as a cylinder with 2,8m height and 0,6m radius, maximum object's weight is 2 tons.  Measurement head is automatically calibrated by the system for chosen working volume (from 120mm x 80mm x 60mm and ends up to 1,2m x 0,8m x 0,6m). Positioning of measurement head in relation to measured object is realized by computer-controlled manipulator. The system is equipped with two independent collision detection modules to prevent damaging measured object with moving sensor’s head. Measurement process is divided into three steps. First step is used for locating any part of object’s surface in assumed measurement volume. Second step is related to calculation of "next best view" position of measurement head on the base of existing 3D scans. Finally small holes in measured 3D surface are detected and measured. All 3D data processing (filtering, ICP based fitting and final views integration) is performed automatically. Final 3D model is created on the base of user specified parameters like accuracy of surface representation and/or density of surface sampling. In the last section of the paper, exemplary measurement result of two objects: biscuit (from the collection of Museum Palace at Wilanów) and Roman votive altar (Lower Moesia, II-III AD) are presented

Multi-Focal Visual Servoing Strategies

Multi-focal vision provides two or more vision devices with different fields of view and measurement accuracies. A main advantage of this concept is a flexible allocation of these sensor resources accounting for the current situational and task performance requirements. Particularly, vision devices with large fields of view and low accuracies can be use

Anatomical evaluation of CT-MRI combined femoral model

<p>Abstract</p> <p>Background</p> <p>Both CT and MRI are complementary to each other in that CT can produce a distinct contour of bones, and MRI can show the shape of both ligaments and bones. It will be ideal to build a CT-MRI combined model to take advantage of complementary information of each modality. This study evaluated the accuracy of the combined femoral model in terms of anatomical inspection.</p> <p>Methods</p> <p>Six normal porcine femora (180 ± 10 days, 3 lefts and 3 rights) with ball markers were scanned by CT and MRI. The 3D/3D registration was performed by two methods, i.e. the landmark-based 3 points-to-3 points and the surface matching using the iterative closest point (ICP) algorithm. The matching accuracy of the combined model was evaluated with statistical global deviation and locally measure anatomical contour-based deviation. Statistical analysis to assess any significant difference between accuracies of those two methods was performed using univariate repeated measures ANOVA with the Turkey post hoc test.</p> <p>Results</p> <p>This study revealed that the local 2D contour-based measurement of matching deviation was 0.5 ± 0.3 mm in the femoral condyle, and in the middle femoral shaft. The global 3D contour matching deviation of the landmark-based matching was 1.1 ± 0.3 mm, but local 2D contour deviation through anatomical inspection was much larger as much as 3.0 ± 1.8 mm.</p> <p>Conclusion</p> <p>Even with human-factor derived errors accumulated from segmentation of MRI images, and limited image quality, the matching accuracy of CT-&-MRI combined 3D models was 0.5 ± 0.3 mm in terms of local anatomical inspection.</p

Muestreo de imágenes de rango en el espacio de variación de la orientación

La informaci&oacute;n proveniente de un conjunto de im&aacute;genes de rango puede utilizarse para producir modelos computacionales en 3D de la escena. Sin embargo, cada imagen esta referida a las coordenadas de la c&aacute;mara en el momento de la adquisici&oacute;n. Encontrar un conjunto de transformaciones tales que, aplicadas a las im&aacute;genes, lleven el conjunto a un sistema coordenado com&uacute;n, es usualmente denominado registro de im&aacute;genes de rango. Uno de los grandes problemas en dicho proceso est&aacute; relacionado con datos seleccionados de forma arbitraria y que no son relevantes en el registro. En &eacute;ste art&iacute;culo se propone un nuevo m&eacute;todo de muestreo, basado en el uso de la informaci&oacute;n local de variaci&oacute;n de la orientaci&oacute;n (curvatura). Se muestra que, el rendimiento del algoritmo es adecuado en comparaci&oacute;n con las t&eacute;cnicas habituales en la reconstrucci&oacute;n de modelos a partir de im&aacute;genes de rango.Palabras claves: Im&aacute;genes de rango, m&eacute;todos de muestreo, registro

Computer Vision and Graphics for Heritage Preservation and Digital Archaeology

The goal of this work is to provide attendees with a survey of topics related to Heritage Preservation and Digital Archeology, which are challenging and motivating subjects to both computer vision and graphics community. These issues have been gaining increasing attention and priority within the scientific scenario and among funding agencies and development organizations over the last years. Motivations to this work are the recent efforts in the digital preservation of cultural heritage objects and sites before degradation or damage caused by environmental factors or human development. One of the main focuses of these researches is the development of new techniques for realistic 3D model building from images, preserving as much information as possible. We intend to introduce and discuss several emerging topics in computer vision and graphics related to the proposed theme while highlighting the major contributions and advances in these fields

REVERSE ENGINEERING IN MODELING OF AIRCRAFT PROPELLER BLADE - FIRST STEP TO PRODUCT OPTIMIZATION

ABSTRACT: Propeller aircrafts have had many ups and downs throughout their use in the aviation history. Due to the current economic recession and price hikes in fuels, propeller aircrafts may yet again be a choice for aerial transport and has thus re-emerged as an active area for research. On modern propeller aircrafts old aluminum propellers are being replaced with fiber reinforced composite propellers. However, owing to their reliability, strength, and integrity, aluminum propellers are still used in military aircrafts. One of the challenges that engineers of these aircraft-type have had to deal with is the non-availability of engineering drawings of these propellers. It is practically impossible to carry out any study, research or modification on such propellers in the absence of correct CAD data. This article proposes a methodology wherein a CAD model of a C-130 aircraft propeller blade can be constructed using reverse engineering techniques. Such a model would help in future aerodynamic as well as structural analyses which includes investigation on structural integrity and the fluid dynamics characteristics of propeller blades. Different steps involved in this process are discussed; starting from laser scanning to obtain the cloud of points data and subsequently generating a CAD model in a commercial CAD software. The model is then imported into an analysis software where quality surface meshes are generated using tetrahedral elements. The purpose is to prepare a meshed model for future computational analysis including CFD (Computational Fluid Dynamics) and FE (Finite Element) analysis. ABSTRAK: Pesawat bebaling mempunyai tempoh pasang surutnya sepanjang penggunaanya dalam sejarah penerbangan. Kini disebabkan oleh kemelesetan ekonomi dan kenaikan harga minyak, pesawat bebaling mungkin akan merupakan pengangkutan udara pilihan dan seterusnya muncul semula sebagai ruangan aktif penyelidikan. Pada pesawat bebaling moden, bebaling aluminium yang lama digantikan dengan bebaling komposit yang diperkuatkan gentian. Namun, disebabkan oleh keupayaan, kekuatan dan integritinya, bebaling aluminium masih diguna pakai bagi pesawat tentera. Salah satu cabaran jurutera bagi pesawat jenis ini, adalah apabila berhadapan dengan tidak adanya lukisan kejuruteraan bagi bebaling ini. Agak mustahil untuk menjalankan sebarang ujian, kajian atau modifkasi terhadap bebaling jenis ini kerana tidak adanya data yang tepat daripada Reka Bentuk Berbantukan Komputer (CAD). Artikel ini mencadangkan metodologi di mana model Reka Bentuk Berbantukan Komputer (CAD) bagi kipas bebaling pesawat C-130 boleh dibina menggunakan teknik kejuruteraan balikan. Model sebegini akan bakal dapat membantu bidang aerodinamik di masa hadapan. Begitu juga dengan analisis struktur yang melibatkan penyelidikan terhadap integriti struktur dan ciri-ciri dinamik bendalir kipas bebaling.  Beberapa proses berbeza diperbincangkan; bermula dengan imbasan laser untuk memperolehi poin kumpulan data dan seterusnya menjanakan model Reka Bentuk Berbantukan Komputer (CAD) dengan menggunakan pengaturcara komersil. Model kemudiannya diimport ke dalam pengaturcara analisis di mana jejaring permukaan dijanakan dengan menggunakan unsur tetrahedron. Ini bertujuan bagi menyediakan model jejaring untuk analisis berkomputer di masa hadapan, termasuklah analisis CFD (Gambar Rajah Aliran Kawalan) dan FE (Unsur Terhingga). KEYWORDS: reverse engineering; cloud data; laser scanning; CAD modeling; propeller blad

Vision numérique et modèles 3D pour imagerie moléculaire sur petits animaux par tomographie optique

Typiquement, en tomographie optique diffuse (TOD), les mesures optiques sont prises en amenant des fibres optiques en contact avec le sujet ou en faisant baigner le sujet dans un fluide adaptateur d'indice. Ces deux approches simplifient grandement le problème inverse pour la reconstruction tomographique, car seule la propagation de la lumière dans les tissus biologiques doit être considérée. Dans le cas de l'imagerie sur petits animaux, il est très difficile d'amener des fibres optiques en contact avec le sujet de façon automatisée sans l'écraser et sans changer sa géométrie. L'utilisation de fluides adaptateurs d'indice simplifie la géométrie du problème à celle du contenant, généralement de forme cylindrique, où se trouve l'animal. Par contre, il n'est pas pratique d'avoir à entretenir un tel système et il est difficile de mettre l'animal dans un fluide sans le noyer. L'utilisation de fluides adaptateurs d'indice atténue le signal optique menant à des mesures plus bruitées. Les sytèmes sans contact permettent d'éviter tous les problèmes mentionnés précédemment, mais nécessitent la mesure de la forme extérieure du sujet. Dans le cadre des présents travaux de recherche, un système de vision numérique utilisant une paire de caméras et un laser pour mesurer la forme extérieure 3D de sujets est présenté. La conception du système de vision numérique 3D vise à faciliter son intégration au système de TOD qui est présentement développé au sein du groupe TomOptUS. Le principal avantage du système de vision numérique est de minimiser la complexité du système de TOD en utlisant le même laser pour les mesures tomographiques optiques et pour les mesures 3D, permettant simultanément l'acquisition de modèles 3D et de données optiques. Cette approche permet de mesurer la position exacte à laquelle la lumière du laser est injectée dans le sujet, alors que cette postion est habituellement déduite et non mesurée par les autres systèmes. Cette information est extrêmement importante pour la reconstruction tomographique. Des mesures 3D précises (<1mm) sont obtenues à l'aide d'algorithmes pour l'étalonnage de l'axe de rotation et de translation. Des mesures 3D d'une forme de référence et d'une souris sont présentées démontrant la précision et l'efficacité du système