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Single Image (single + image)
Selected AbstractsDiorama Construction From a Single ImageCOMPUTER GRAPHICS FORUM, Issue 3 2007J. Assa Abstract Diorama artists produce a spectacular 3D effect in a confined space by generating depth illusions that are faithful to the ordering of the objects in a large real or imaginary scene. Indeed, cognitive scientists have discovered that depth perception is mostly affected by depth order and precedence among objects. Motivated by these findings, we employ ordinal cues to construct a model from a single image that similarly to Dioramas, intensifies the depth perception. We demonstrate that such models are sufficient for the creation of realistic 3D visual experiences. The initial step of our technique extracts several relative depth cues that are well known to exist in the human visual system. Next, we integrate the resulting cues to create a coherent surface. We introduce wide slits in the surface, thus generalizing the concept of cardboard cutout layers. Lastly, the surface geometry and texture are extended alongside the slits, to allow small changes in the viewpoint which enriches the depth illusion. [source] Adding Depth to Cartoons Using Sparse Depth (In)equalitiesCOMPUTER GRAPHICS FORUM, Issue 2 2010D. Sýkora Abstract This paper presents a novel interactive approach for adding depth information into hand-drawn cartoon images and animations. In comparison to previous depth assignment techniques our solution requires minimal user effort and enables creation of consistent pop-ups in a matter of seconds. Inspired by perceptual studies we formulate a custom tailored optimization framework that tries to mimic the way that a human reconstructs depth information from a single image. Its key advantage is that it completely avoids inputs requiring knowledge of absolute depth and instead uses a set of sparse depth (in)equalities that are much easier to specify. Since these constraints lead to a solution based on quadratic programming that is time consuming to evaluate we propose a simple approximative algorithm yielding similar results with much lower computational overhead. We demonstrate its usefulness in the context of a cartoon animation production pipeline including applications such as enhancement, registration, composition, 3D modelling and stereoscopic display. [source] Diorama Construction From a Single ImageCOMPUTER GRAPHICS FORUM, Issue 3 2007J. Assa Abstract Diorama artists produce a spectacular 3D effect in a confined space by generating depth illusions that are faithful to the ordering of the objects in a large real or imaginary scene. Indeed, cognitive scientists have discovered that depth perception is mostly affected by depth order and precedence among objects. Motivated by these findings, we employ ordinal cues to construct a model from a single image that similarly to Dioramas, intensifies the depth perception. We demonstrate that such models are sufficient for the creation of realistic 3D visual experiences. The initial step of our technique extracts several relative depth cues that are well known to exist in the human visual system. Next, we integrate the resulting cues to create a coherent surface. We introduce wide slits in the surface, thus generalizing the concept of cardboard cutout layers. Lastly, the surface geometry and texture are extended alongside the slits, to allow small changes in the viewpoint which enriches the depth illusion. [source] PATHS IN TRANSNATIONAL TIME-SPACE: REPRESENTING MOBILITY BIOGRAPHIES OF YOUNG SWEDESGEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 1 2008Lotta Frändberg ABSTRACT. This article sets out to capture and describe individual transnational mobility from a long-term, biographical perspective. The purpose is to discuss the use of a time-geographical form of notation to represent people's transnational mobility as paths in time and space, and to demonstrate how such representations can contribute to explaining some of the dynamics of longdistance mobility. An advantage of using time-space paths is that several aspects of an individual's travel biography can be represented in a single image: intensity and extensity are immediately evident, and the temporal and spatial relationships between the various mobility actions are made visible. Using data describing all transnational trips taken during childhood and adolescence by sixty-two Swedish youth with different backgrounds, three aspects of how trajectories develop over time are discussed in more detail. The first concerns overall change in travel pattern with time. A dominant pattern of increase in travel with increasing age is observed, indicating the importance of further investigating how travel behaviour is related to experience and life-course transitions. Second, sequential relationships between migration and temporary mobility are examined. In spite of the relatively small number of respondents, a wide range of such relationships are disclosed in the material. Third, regularity and repetition in long-distance travel patterns is discussed as an increasingly important aspect of contemporary transnational mobility. Among these young people, highly regular travel is often motivated by enduring long-distance social relationships, but is also generated by leisure or holiday travel alone. [source] A practical approach for estimating illumination distribution from shadows using a single imageINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 2 2005Taeone Kim Abstract This article presents a practical method that estimates illumination distribution from shadows using only a single image. The shadows are assumed to be cast on a textured, Lambertian surface by an object of known shape. Previous methods for illumination estimation from shadows usually require that the reflectance property of the surface on which shadows are cast be constant or uniform, or need an additional image to cancel out the effects of varying albedo of the textured surface on illumination estimation. But, our method deals with an estimation problem for which surface albedo information is not available. In this case, the estimation problem corresponds to an underdetermined one. We show that the combination of regularization by correlation and some user-specified information can be a practical method for solving the underdetermined problem. In addition, as an optimization tool for solving the problem, we develop a constrained Non-Negative Quadratic Programming (NNQP) technique into which not only regularization but also multiple linear constraints induced by user-specified information are easily incorporated. We test and validate our method on both synthetic and real images and present some experimental results. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 143,154, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20047 [source] Fast gradual matching measure for image retrieval based on visual similarity and spatial relationsINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 7 2006Jean-François Omhover In this article, we propose a new method to retrieve images containing a request set of regions. The user is asked to specify a set of regions belonging to a single image. Then this request set of regions is compared to the sets of the regions of the images in the database. We propose a comparison measure that not only evaluates the similarity of regions one to the other, but that also takes into account the spatial configuration of the regions. The spatial structure of the regions is represented by means of fuzzy spatial relations, like horizontal and vertical disposal and connexity. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 711,723, 2006. [source] Multivariate analysis of congruent images (MACI)JOURNAL OF CHEMOMETRICS, Issue 5-7 2005Lennart Eriksson Abstract The multivariate analysis of congruent images (MACI) is discussed. Here, each image represents one observation and the data set contains a set of congruent images. With ,congruent images' we mean a set of images, properly pre-processed, oriented and aligned, so that each data element (,feature', pixel) corresponds to the same element across all images. An example may be a set of frames from a fixed video camera looking at a stable process. The purpose of a MACI is to find and express patterns over a set of images for the purpose of classification or quantitative regression-like relationships. This is in contrast to standard image analysis, which is usually concerned with a single image and the identification of parts of the image, for example tumour tissue versus normal. We also extend MACI to the case with a set of images that initially are not fully congruent, but are made so by the use of wavelet analysis and the distributions of the wavelet coefficients. Thus, the resulting description forms a set of congruent vectors amenable to multivariate data analysis. The MACI approach will be illustrated by four data sets, three easy-to-understand tutorial image data sets and one industrial image data set relating to quality control of steel rolls. Copyright © 2006 John Wiley & Sons, Ltd. [source] Vision-only control and guidance for aircraftJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 10 2006Alison A. Proctor An unmanned aerial vehicle usually carries an array of sensors whose output is used to estimate vehicle attitude, velocity, and position. This paper details the development of guidance, navigation, and control strategies for a glider, which is capable of flying a terminal trajectory to a known fixed object using only a single vision sensor. Controlling an aircraft using only vision presents two unique challenges: First, absolute state measurements are not available from a single image; and second, the images must be collected and processed at a high rate to achieve the desired controller performance. The image processor utilizes an integral image representation and a rejective cascade filter to find and classify simple features in the images, reducing the image to the most probable pixel location of the destination object. Then, an extended Kalman filter uses measurements obtained from a single image to estimate the states that would otherwise be unobservable in a single image. In this research, the flights are constrained to keep the destination object in view. The approach is validated through simulation. Finally, experimental data from autonomous flights of a glider, instrumented only with a single nose-mounted camera, intercepting a target window during short low-level flights, are presented. © 2006 Wiley Periodicals, Inc. [source] Dentists' preferences of anterior tooth proportion,a Web-based studyJOURNAL OF PROSTHODONTICS, Issue 3 2000Stephen F. Rosenstiel BDS Purpose This study aimed to determine dentists' esthetic preferences of the maxillary anterior teeth as influenced by different proportions. The goal was to link choices to demographic data as to the experience, gender, and training of the dentist. Materials and Methods Computer-manipulated images of the 6 maxillary anterior teeth were generated from a single image and assigned to 5 tooth-height groups (very short, short, normal height, tall, and very tall). For each group, 4 images were generated by manipulating the relative proportion of the central incisors, lateral incisors, and canines according to the proportions 62% (or "golden proportion"), 70%, 80%, and "normal" or not further altered. The images were randomly ordered on a web page that contained a form asking for demographic data and fields asking for a ranking of the images. Dentists were asked via e-mail to visit the web page and complete the survey. The responses were tabulated and analyzed with repeated measures logistic regression with the alpha at 0.05. A subset of North American respondents was chosen for further analysis. Results A total of 549 valid responses were received and analyzed from dentists in 38 countries. There were statistically significant differences in all groups for the variables of proportion, group (tooth height), and their interaction. The 80% proportion was judged best for the Very Short and Short groups. Three of the choices were almost equally picked for the Normal Height and Tall groups, and the golden proportion was judged best for the Very Tall group. The variables of year of graduation, gender, professional activity, generalist or specialist, or number of patients were not significantly correlated with the choices for the North American respondents. Conclusions Dentists preferred the 80 percent proportion when viewing short or very short teeth and the golden proportion when viewing very tall teeth. Golden proportion was worst for normal height or shorter teeth and the 80% proportion for tall or very tall teeth. They picked no clear-cut best for normal height or tall teeth, and their choices could not be predicted based on gender, specialist training, experience, or patient load. [source] Binocular interaction and performance of visual tasksOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 2 2004Maria S. Justo Abstract Binocular vision implies the fusion of the right and left retinal images to perceive a single image. For this, interocular interaction is required. We measured the reaction times to carry out a visual fixation task in order to determine whether binocular interaction influences performance. Several combinations of test and distraction stimuli were monocularly and binocularly presented to one monkey and three human subjects. The overall median reaction times were 340 ms for the animal and 308, 342 and 381 for human subjects 1, 2 and 3 respectively. Reaction time was shorter when the test stimulus was presented binocularly. Moreover, we observed that the presence of a distraction stimulus increased the reaction time and that a correlated distraction stimulus had a greater influence on this increase than an uncorrelated distraction stimulus. These findings indicate that with binocular vision a more rapid performance of a visual task occurs. [source] Temporal stability of an NDVI-LAI relationship in a Napa Valley vineyardAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2003LEE F. JOHNSON Abstract Remotely sensed values for normalised difference vegetation index (NDVI) were derived periodically from high-resolution Ikonos satellite images during the 2001 growing season, and compared with ground measurements of vineyard leaf area index (LAI) during that same period. These two derived variables were strongly related in six vineyard blocks on each of four occasions (R2= 0.91 to 0.98). Linear regression equations relating these two derived variables did not differ significantly by time-step, and a single equation accounted for 92 per cent of the variance in the combined dataset. Such temporal stability in that relationship opens the possibility of transforming NDVI maps to LAI units, at least on a localised basis, and minimising (or even eliminating) subsequent ground calibration. This reduction in fieldwork would then decrease information cost for viticulturists who wish to monitor LAI sequentially within season, or who wish to track year-to-year changes in climax LAI with a single image collected annually. To take advantage of this cost reduction, temporal consistency in spectral data values comprising NDVI must be assured. This present paper addresses that issue. [source] Concurrent Viewing of Multiple Attribute-Specific SubspacesCOMPUTER GRAPHICS FORUM, Issue 3 2008Robert Sisneros Abstract In this work we present a point classification algorithm for multi-variate data. Our method is based on the concept of attribute subspaces, which are derived from a set of user specified attribute target values. Our classification approach enables users to visually distinguish regions of saliency through concurrent viewing of these subspaces in single images. We also allow a user to threshold the data according to a specified distance from attribute target values. Based on the degree of thresholding, the remaining data points are assigned radii of influence that are used for the final coloring. This limits the view to only those points that are most relevant, while maintaining a similar visual context. [source] Reanimating Faces in Images and VideoCOMPUTER GRAPHICS FORUM, Issue 3 2003V. Blanz This paper presents a method for photo-realistic animation that can be applied to any face shown in a single imageor a video. The technique does not require example data of the person's mouth movements, and the image to beanimated is not restricted in pose or illumination. Video reanimation allows for head rotations and speech in theoriginal sequence, but neither of these motions is required. In order to animate novel faces, the system transfers mouth movements and expressions across individuals, basedon a common representation of different faces and facial expressions in a vector space of 3D shapes and textures. This space is computed from 3D scans of neutral faces, and scans of facial expressions. The 3D model's versatility with respect to pose and illumination is conveyed to photo-realistic image and videoprocessing by a framework of analysis and synthesis algorithms: The system automatically estimates 3D shape andall relevant rendering parameters, such as pose, from single images. In video, head pose and mouth movements aretracked automatically. Reanimated with new mouth movements, the 3D face is rendered into the original images. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Animation [source] Training evaluation of a course in diabetic retinopathy screeningEUROPEAN DIABETES NURSING, Issue 2 2005R Pauli PhD Senior Lecturer Abstract The success and effectiveness of diabetic screening programmes are dependent on the availability of appropriately trained image graders. This study was designed to evaluate graders enrolled on a locally devised, formal training course by means of a performance-based measure. The course consisted of four days of classroom-based tuition followed by three months of practice-based learning in the workplace. The aim was to establish whether trainees showed an improvement in their ability to grade images, and secondly whether test sets of images are useful in measuring training outcome. Thirteen trainees were required to grade a test set of 24 single images both before and after training. A significant improvement in sensitivity (from 35% before training to 45% after training) was observed as a result of training but at a cost of a decline in specificity. Trainees' confidence ratings measured on a five-point scale increased from an average of 2.4 to 4.1 (p<0.01). We concluded that the course needs to focus more on trainees' ability to discriminate between normal and abnormal images as well as improving grading accuracy in line with increased grading confidence. Test-based course evaluation can be seen to be a valuable instrument in establishing a quality standard for stated learning outcomes. In this research it has clearly indicated weaknesses of the training programme in its current form. Copyright © 2005 FEND. [source] The bootstrap and cross-validation in neuroimaging applications: Estimation of the distribution of extrema of random fields for single volume tests, with an application to ADC mapsHUMAN BRAIN MAPPING, Issue 10 2007Roberto Viviani Abstract We discuss the assessment of signal change in single magnetic resonance images (MRI) based on quantifying significant departure from a reference distribution estimated from a large sample of normal subjects. The parametric approach is to build a test based on the expected distribution of extrema in random fields. However, in conditions where the variance is not uniform across the volume and the smoothness of the images is moderate to low, this test may be rather conservative. Furthermore, parametric tests are limited to datasets for which distributional assumptions hold. This paper investigates resampling methods that improve statistical tests for signal changes in single images in such adverse conditions, and that can be used for the assessment of images taken for clinical purposes. Two methods, the bootstrap and cross-validation, are compared. It is shown that the bootstrap may fail to provide a good estimate of the distribution of extrema of parametric maps. In contrast, calibration of the significance threshold by means of cross-validation (or related sampling without replacement techniques) address three issues at once: improved power, better voxel-by-voxel estimate of variance by local pooling, and adaptation to departures from ideal distributional assumptions on the signal. We apply the cross-validated tests to apparent diffusion coefficient maps, a type of MRI capable of detecting changes in the microstructural organization of brain parenchyma. We show that deviations from parametric assumptions are strong enough to cast doubt on the correctness of parametric tests for these images. As case studies, we present parametric maps of lesions in patients suffering from stroke and glioblastoma at different stages of evolution. Hum Brain Mapp 2007. © 2007 Wiley-Liss, Inc. [source] Analysis of video images from a gas,liquid transfer experiment: a comparison of PCA and PARAFAC for multivariate image analysisJOURNAL OF CHEMOMETRICS, Issue 7 2003Stephen P. Gurden Abstract The use of chemical imaging is a developing area which has potential benefits for chemical systems where spatial distribution is important. Examples include processes in which homogeneity is critical, such as polymerizations, pharmaceutical powder blending and surface catalysis, and dynamic processes such as the study of diffusion rates or the transport of environmental pollutants. Whilst single images can be used to determine chemical distribution patterns at a given point in time, dynamic processes can be studied using a sequence of images measured at regular time intervals, i.e. a movie. Multivariate modeling of image data can help to provide insight into the important chemical factors present. However, many issues of how best to apply these models remain unclear, especially when the data arrays involved have four or five different dimensions (height, width, wavelength, time, experiment number, etc.). In this paper we describe the analysis of video images recorded during an experiment to investigate the uptake of CO2 across a free air,water interface. The use of PCA and PARAFAC for the analysis of both single images and movies is described and some differences and similarities are highlighted. Some other image transformation techniques, such as chemical mapping and histograms, are found to be useful both for pretreatment of the raw data and for dimensionality reduction of the data arrays prior to further modeling. Copyright © 2003 John Wiley & Sons, Ltd. [source] Digital photography: A primer for pathologistsJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 2 2004Roger S. Riley Abstract The computer and the digital camera provide a unique means for improving hematology education, research, and patient service. High quality photographic images of gross specimens can be rapidly and conveniently acquired with a high-resolution digital camera, and specialized digital cameras have been developed for photomicroscopy. Digital cameras utilize charge-coupled devices (CCD) or Complementary Metal Oxide Semiconductor (CMOS) image sensors to measure light energy and additional circuitry to convert the measured information into a digital signal. Since digital cameras do not utilize photographic film, images are immediately available for incorporation into web sites or digital publications, printing, transfer to other individuals by email, or other applications. Several excellent digital still cameras are now available for less than $2,500 that capture high quality images comprised of more than 6 megapixels. These images are essentially indistinguishable from conventional film images when viewed on a quality color monitor or printed on a quality color or black and white printer at sizes up to 11×14 inches. Several recent dedicated digital photomicroscopy cameras provide an ultrahigh quality image output of more than 12 megapixels and have low noise circuit designs permitting the direct capture of darkfield and fluorescence images. There are many applications of digital images of pathologic specimens. Since pathology is a visual science, the inclusion of quality digital images into lectures, teaching handouts, and electronic documents is essential. A few institutions have gone beyond the basic application of digital images to developing large electronic hematology atlases, animated, audio-enhanced learning experiences, multidisciplinary Internet conferences, and other innovative applications. Digital images of single microscopic fields (single frame images) are the most widely utilized in hematology education at this time, but single images of many adjacent microscopic fields can be stitched together to prepare "zoomable" panoramas that encompass a large part of a microscope slide and closely simulate observation through a real microscope. With further advances in computer speed and Internet streaming technology, the virtual microscope could easily replace the real microscope in pathology education. Later in this decade, interactive immersive computer experiences may completely revolutionize hematology education and make the conventional lecture and laboratory format obsolete. Patient care is enhanced by the transmission of digital images to other individuals for consultation and education, and by the inclusion of these images in patient care documents. In research laboratories, digital cameras are widely used to document experimental results and to obtain experimental data. J. Clin. Lab. Anal. 18:91,128, 2004. © 2004 Wiley-Liss, Inc. [source] Source Camera Identification for Heavily JPEG Compressed Low Resolution Still Images,JOURNAL OF FORENSIC SCIENCES, Issue 3 2009Erwin J. Alles M.Sc. Abstract:, In this research, we examined whether fixed pattern noise or more specifically Photo Response Non-Uniformity (PRNU) can be used to identify the source camera of heavily JPEG compressed digital photographs of resolution 640 × 480 pixels. We extracted PRNU patterns from both reference and questioned images using a two-dimensional Gaussian filter and compared these patterns by calculating the correlation coefficient between them. Both the closed and open-set problems were addressed, leading the problems in the closed set to high accuracies for 83% for single images and 100% for around 20 simultaneously identified questioned images. The correct source camera was chosen from a set of 38 cameras of four different types. For the open-set problem, decision levels were obtained for several numbers of simultaneously identified questioned images. The corresponding false rejection rates were unsatisfactory for single images but improved for simultaneous identification of multiple images. [source] SOLUTIONS FOR EXTERIOR ORIENTATION IN PHOTOGRAMMETRY: A REVIEWTHE PHOTOGRAMMETRIC RECORD, Issue 100 2002Pierre Grussenmeyer Abstract The determination of the attitude, the position and the intrinsic geometric characteristics of the camera is recognised as the fundamental photogrammetric problem. It can be summarised as the determination of camera interior and exterior orientation parameters, as well as the determination of 3D coordinates of object points. The term "exterior orientation" of an image refers to its position and orientation related to an exterior (object space) coordinate system. Several methods can be applied to determine the parameters of the orientation of one, two or more photos. The orientation can be processed in steps (as relative and absolute orientation) but simultaneous methods (such as bundle adjustments) are now available in many software packages. Several methods have also been developed for the orientation of single images. They are based in general on geometric and topological characteristics of imaged objects. This paper presents a survey of classical and modern methods for the determination of the exterior parameters in photogrammetry, some of which are available as software packages (with practical examples) on the Internet. The methods presented are classified in three principal groups. In the first. a selection of approximate methods for applications that do not require great accuracy is presented. Such methods are also used to calculate values required for iterative processes. In the second group, standard point-bused methods derived from collinearity, coplanarity or coangularity conditions are briefly reviewed, followed by line-based approaches. The third group represents orientation methods based on constraints and on concepts of projective geometry, which are becoming of increasing interest for photogrammetrists. In the last section, the paper gives a summary of existing strategies for automatic exterior orientation in aerial photogrammetry. Résumé La détermination de l'attitude, de la position et des caractéristiques intrinsèques de la chambre photographique constitue un problème fondamental en photogrammétrie. Il se résume à la détermination des paramètres de l'orientation de la chambre de prise de vue (paramètres des orientations externe et interne), ainsi qu'à la détermination des coordonnées 30 des points de l'objet. L'orientation externe se rapporte à la détermination de la position et de l'orientation d'une chambre par rapport à un système externe de coordonnées. Différentes méthodes peuvent être utilisées pour calculer les éléments dorientation externe d'une photo, d'un couple ou de plusieurs photos. Le calcul de l'orientation peut être réalisé par étapes (par exemple les orientations relative et absolue) mais les méthodes simultanées (la compensation par faisceaux par exemple) sont actuellement proposées dans la plupart des logiciels. Plusieurs méthodes ont aussi été développées pour l'orientation d'images isolées. Ells sont basées en général sur les caactéristiques géométriques et topologiques des objets photographiés. Dans cet article on présente un ensemble de méthodes classiques et modernes pour la détermination des paramètres de l'orientation externe, certaines d'entre elles étant téléchargeables sous la forme d'applications sur Internet. Les méthodes présentées sont classées en trois groupes principaux. Le premier groupe contient une sélection de méthodes approximatives utilisées d'habitude quand une grande précision n'est pas exigée, ou encore pour calculer des vuleurs approchées des paramètres extrinsèques requises pour les méthodes itératives rigoureuses. Dans le deuxième groupe, on rappelle brièvement les jondements des méthodes basées sur les conditions photogrammétriques fondamentales (la colinéarité, la coplanéité et la coangularité). Dans ce groupe, les méthodes basées sur l'extraction des points ou des lignes sont également abordées. Le troisième groupe traite des méthodes d'orientation basées sur les contraintes et les concepts de la géométrie projective, de plus en plus utilisées par les photogrammètres. Le dernier paragraphe se rapporte aux méthodes destinées à automatiser le calcul de l'orientation externe en photogrammétrie aérienne. Zusummenfussung Die Bestimmung der Neigung, der Position und den geometrischen parametern der Kamera wird als das fundamentale Problem der Photogrammetrie angesehen. Es kann zusammenfassend sowohl als die Bestimmung der Parameter der inneren und äusseren Orientierung der Kamera angesehen werden, als auch als die Bestimmung von 3D Koordinaten von Objektpunkten. Der Ausdruck "äussere Orientierung" eines Bildes bezieht sich auf die Lage und Orientierung bezogen auf ein äusseres (Objektraum-) Koordinatensystem. Es können verschiedene Methoden angewandt werden, um die Parameter von einem, zwei oder mehreren Bildern zu bestimmen. Die orientierung kann in Schritten erfolgen, was als Relative und Absolute Orientierung bezeichnet wird, aber auch simultane Methoden, wie die Bündelausgleichung, sind in vielen Softwarepaketen implementiert. Es wurden auch Methoden für die Orientierung von Einzelbildern entwickelt, die geometrische und topologische Eigenschaften der abgebildeten Objekte nutzen. In diesem Beitrag wird Beitrag wird eine Studie klassischer und moderner Methoden der Photogrammetrie zur Bestimmung der Parameter der äßeren Orientierung vorgestellt, wovon einige in Softwarepaketen zur Verfügung stehen, die von praktischen Beispielen im Internet ergänzt werden. Die untersuchten Methoden werden in drei Hauptgruppen eingeteilt. In einer ersten Gruppe werden Näherungslösungen vorgestellt, die für Anwendungen mit geringen Genauigkeitsanforderungen geeignet sind. Diese Methoden werden ansonsten für die Näherngswertberechunggen für iterative Prozesse verwendet. IN der zweiten Gruppe werden zuerst die punktbasierten Standardmethoden vorgestellt, die von Bedingungen zur Kollinearität. Koplanarität und Kowinkligkeit abgeletet sind. Danach folgen linienbasierte Ansätze. Die dritte Gruppe umfasst Orientierungsmethoden, die auf Zwangsbedingungen und auf Konzepte der projektiven Geometrie aufbauen, die für Photogrammeter von zunehmendem Interesse sind, Im letzten Abschnitt wird eine Zusammenfassung existierender Strategien für eine automatische äussere orientierung in der Luftbildphotogrammetrie gegeben. [source] Solutions for Exterior Orientation in Photogrammetry: A ReviewTHE PHOTOGRAMMETRIC RECORD, Issue 100 2002Pierre Grussenmeyer The determination of the attitude, the position and the intrinsic geometric characteristics of the camera is recognised as the fundamental photogrammetric problem. It can be summarised as the determination of camera interior and exterior orientation parameters, as well as the determination of 3D coordinates of object points. The term "exterior orientation"of an image refers to its position and orientation related to an exterior (object space) coordinate system. Several methods can be applied to determine the parameters of the orientation of one, two or more photos. The orientation can be processed in steps (as relative and absolute orientation) but simultaneous methods (such as bundle adjustments) are now available in many software packages. Several methods have also been developed for the orientation of single images. They are based in general on geometric and topological characteristics of imaged objects. This paper presents a survey of classical and modern methods for the determination of the exterior parameters in photogrammetry, some of which are available as software packages (with practical examples) on the Internet. The methods presented are classified in three principal groups. In the first, a selection of approximate methods for applications that do not require great accuracy is presented. Such methods are also used to calculate values required for iterative processes. In the second group, standard point,based methods derived from collinearity, coplanarity or coangularity conditions are briefly reviewed, followed by line,based approaches. The third group represents orientation methods based on constraints and on concepts of projective geometry, which are becoming of increasing interest for photogrammetrists. In the last section, the paper gives a summary of existing strategies for automatic exterior orientation in aerial photogrammetry. [source] | ||||||||||||||||||||||