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Titre : Accuracy improvement in digital matching Type de document : Rapport Auteurs : Dan Rosenholm, Auteur Editeur : Stockholm : Royal Institute of Technology Année de publication : 1986 Collection : Fotogrammetriska meddelanden, ISSN 0071-8068 num. 52 Importance : 137 p. Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] appariement automatique
[Termes IGN] coefficient de corrélation
[Termes IGN] méthode des moindres carrés
[Termes IGN] niveau de gris (image)
[Termes IGN] parallaxe
[Termes IGN] photographie aérienneIndex. décimale : 33.30 Photogrammétrie numérique Résumé : (auteur) Accuracy aspects of matching algorithms based on the least square method are investigated. Parallaxes computed automatically with matching methods have been compared to manual measurements made in a stereocomparator. Examples have been taken from large scale and small scale aerial photographs and from close-range photogrammetry. Different linear geometric and radiometric parameters have been used. Other changes in the algorithm have also been investigated such as the effect of using different window sizes. The results show that window sizes below 20X20 pixels should not be used and, that affine parameters should not be used when the window size is lower than 30X30 pixels, both for reasons of reliability. The precision obtainable was between 10-15 pm, expressed as r.m.s. Gross error detection is to a large extend possible. The methods for matching of single points are not operative at this stage of development. In the investigation, a multi-point matching method using finite elements has been formulated. Parallaxes of points in a grid connected with bilinear elements are computed simultaniously directly from image data using the least square technique. Constraints, such as minimizing of the curvature, are implemented as ficticious observations. Methods for inclusion of breaklines and discontinuites, where it is possible to include the position as as unknown, are also formulated. Prelimi-nary tests of the multi-point matching method have been performed. Note de contenu : 1- Introduction
2- Investigation methods
3- The basic least square matching algorithm
4- Additional parameters
5- Miti-point matching
6- Other investigated improvements
7- Results
8- Discussion
9- ConclusionNuméro de notice : 25025 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Rapport de recherche Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92975 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 25025-01 33.30 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible
Titre : Digital matching of stereo Images Type de document : Rapport Auteurs : Kennert Torlegard, Éditeur scientifique Editeur : Stockholm : Royal Institute of Technology Année de publication : 1986 Collection : Fotogrammetriska meddelanden, ISSN 0071-8068 num. 51 Importance : 82 p. Format : 21 x 30 cm Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] appariement automatique
[Termes IGN] couple stéréoscopique
[Termes IGN] parallaxe
[Termes IGN] structure hiérarchique de données
[Termes IGN] transformation de FourierIndex. décimale : 33.30 Photogrammétrie numérique Résumé : (auteur) This project contains a study of matching algorithms sui-table for detection of stereo parallax in pairs of digital images. New algorithms have been developed. The influence from radiometric differences on the accuracy of the matching has been studied. The intention was also to study hierarchi-cal data structures in order to speed up the processes for the measuring of parallaxes between digital images. During the course of the research new problems were formu-lated. One was the possibility to use phase correlation from Fourier transforms as a tool to find approximate value before starting the precise matching of stereo pairs of images. Another problem was the use of digital techniques for the restoration of images before precise matching. A third problem was the necessity to develop reflectance models for stereoscopic imaging of objects that are composed of several types of surfaces with different optical proper ties. Results of importance for digital photogrammetry have been obtained as follows. Preprocessing in order to increase matching precision has to use special filtering techniques. Standard methods can even impair the final accuracy of parallaxes derived with digital matching. Pixel spacing has to be tuned to photographic MTF and the radiometric charac-teristics of the image scanner. The matching windows should be larger than usually applied in order to optimize accu-racy. Surface matching rather than point-wise determination of parallaxes is a promising possibility. For the acquisi-tion of approximate matching positions we have found that phase-correlation with Fourier transforms are not suitable. Note de contenu : - Kennert Torlegard: Digital Matching of Images having Different Perspectives
- Ulf Almroth: Digital Photogrammetry: Pixel Size, Image Quality and Noise Considerations
- Jan-Olov Fallvik: Image Restoration Methods as Preprocessing Tools in Digital Stereo Matching
- John Stokes: Are Phase Shift Methods Suitable for Image Matching in Photogrammetry?Numéro de notice : 25026 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Rapport de recherche Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92976 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 25026-01 33.30 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible