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  • 1
    Electronic Resource
    Electronic Resource
    Oxford UK and Boston, USA : Blackwell Publishers Ltd.
    The @photogrammetric record 16 (1998), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Digital still cameras have been widely adopted for close range photogrammetry and machine vision applications. Due to the advantages of onboard storage of digital images, portability and rapid data processing, digital still cameras are rapidly becoming standard equipment for measurement tasks such as industrial metrology and heritage recording. As for any metric application, the accuracy of the derived object data is dependent, amongst many other factors, on the accuracy of the camera calibration. For the vast majority of photogrammetric applications, use of the simple case of a block invariant calibration model comprising the primary physical parameters, including the principal point position, is sufficient. However, cameras designed for photojournalism and domestic use, such as the Kodak DCS420 and 460 cameras, are well known for their calibration instability because the design is based on a 35 mm SLR camera body. In particular, previous research has shown that the principal point location is prone to movement during normal handling of the camera, due to the mounting mechanism of the CCD array. This paper reports on an investigation of the physical behaviour of the principal point location and compares different calibration parameter models for the Kodak DCS420 and DCS460 digital still cameras.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 15 (1997), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Wind tunnel engineers require measurements of position and orientation of aerospace models under test conditions. The measurement technique must be non-contact, non-intrusive and have a high sample rate. Videometric techniques based on multiple, synchronized CCD cameras can supply position and orientation data at 30Hz or 60Hz with acceptable accuracies. This paper describes a data acquisition system designed and implemented at NASA Langley Research Center to capture the position and orientation of free-flight aerospace models. System calibration and data processing techniques are discussed. Two examples of model tests will be described and examples of data output will be presented.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 10 (1981), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: This paper describes a system for the interior, relative and absolute orientations of steroplotter models, using a minicomputer interfaced to the plotter as an aid to the operator. Both aerial and terrestrial models were included in the evaluation of the system but the emphasis is on close range work where significant improvements in efficiency and precision can be obtained.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn décrit un système d'aide à la restitution (orientation relative et orientation absolue) utilisant un mini-ordinateur relié par une interface à l'appareil de restitution. II vaut tant pour les couples terrestres que les couples aériens; on a cependant accordé une attention spéciale au cas de la photogrammétrie à courte distance oú certaines dispositions permettent un gain significatif d'exactitude.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungIn dem Artikel wird ein System zur inneren, relativen und absoluten Orientierung von Stereomodellen unter Benutzung eines Minirechners beschrieben, der zur Unterstützung des Auswerters an das Stereokartiergerät angeschlossen ist. Obwohl bei der Analyse des Systems sowohl Luftbilder als auch terrestrische Bilder betrachtet werden, liegt das Schwergewicht auf der Nahphotogrammetrie, wo dadurch bedeutende Verbesserungen in bezug auf Leistungsfähigkeit und Genauigkeit erhalt en werden können.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford UK and Boston, USA : Blackwell Publishers Ltd.
    The @photogrammetric record 16 (1998), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Imaging systems founded on current digital camera technology are finding widespread use in high precision measurement applications. A single digital CCD camera, or an array of such cameras, equipped with ring lighting equipment is commonly used to acquire imagery of high contrast retroreflective targets placed on the object at discrete locations to signalize points of interest. The precise and accurate measurement of each imaged target location is a fundamental requirement if suitable measurement tolerances are to be obtained. Whilst such systems are undoubtedly capable of producing excellent results, the practical effects of target image quality on the photogrammetric measurement process is in need of careful consideration. This paper revisits some fundamentals of the optical imaging of retrotargets and investigates some abilities of a range of digital camera systems to provide images of retrotargets that are appropriate to the measurement process. Some experimental results are presented including the imaging of planar arrays of differing sized retrotargets at differing angles and exposures and a series of network analyses in which the level of target image intensity has been varied systematically.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford UK and Boston, USA : Blackwell Publishers Ltd.
    The @photogrammetric record 15 (1996), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford UK and Boston, USA : Blackwell Publishers Ltd.
    The @photogrammetric record 15 (1995), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: The development of still video CCD cameras with digital image storage has made feasible the concept of offline, single sensor vision metrology. This paper reports on practical evaluations of such a system for dimensional inspection of aircraft tooling and for structural monitoring for large scale engineering. A further application of still video technology for low altitude aerial mapping is also reported. In each case a Kodak DCS200 camera has been employed for the photography in order to take advantage of the relatively high sensor resolution and adequate on-board image storage capacity. Aspects of the measurement operations, which yielded object space accuracies to 1:80 000 in the industrial measurement projects, are discussed and the results analysed.
    Type of Medium: Electronic Resource
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  • 7
    Publication Date: 1996-08-01
    Description: Close range photogrammetry is a sensing technique that allows the three-dimensional coordinates of selected points on a surface of almost any dimension and orientation to be assessed. Surface characterisations of paraboloidal reflecting surfaces at the ANU using photogrammetry have indicated that three-dimensional coordinate precisions approaching 1:20,000 are readily achievable using this technique. This allows surface quality assessments to be made of large solar collecting devices with a precision that is difficult to achieve with other methods.
    Print ISSN: 0199-6231
    Electronic ISSN: 1528-8986
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 8
    Publication Date: 2018-06-05
    Description: Some techniques for laboratory calibration and characterization of video cameras used with frame grabber boards are presented. A laser-illuminated displaced reticle technique (with camera lens removed) is used to determine the camera/grabber effective horizontal and vertical pixel spacing as well as the angle of non-perpendicularity of the axes. The principal point of autocollimation and point of symmetry are found by illuminating the camera with an unexpanded laser beam, either aligned with the sensor or lens. Lens distortion and the principal distance are determined from images of a calibration plate suitable aligned with the camera. Calibration and characterization results for several video cameras are presented. Differences between these laboratory techniques and test range and plumb line calibration are noted.
    Keywords: Instrumentation and Photography
    Format: application/pdf
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  • 9
    Publication Date: 2019-07-27
    Description: Some techniques for laboratory calibration and characterization of video cameras used with frame grabber boards are presented. A laser-illuminated displaced reticle technique (with camera lens removed) is used to determine the camera/grabber effective horizontal and vertical pixel spacing as well as the angle of nonperpendicularity of the axes. The principal point of autocollimation and point of symmetry are found by illuminating the camera with an unexpanded laser beam, either aligned with the sensor or lens. Lens distortion and the principal distance are determined from images of a calibration plate suitably aligned with the camera. Calibration and characterization results for several video cameras are presented. Differences between these laboratory techniques and test range and plumb line calibration are noted.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Close-Range Photogrammetry Meets Machine Vision; Sept. 3-7, 1990; Zurich; Switzerland
    Format: text
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  • 10
    Publication Date: 2019-07-13
    Description: Small format, medium resolution CCD cameras are at present widely used for industrial metrology applications. Large format, high resolution CCD cameras are primarily in use for scientific applications, but in due course should increase both the range of applications and the object space accuracy achievable by close range measurement. Slow scan, cooled scientific CCD cameras provide the additional benefit of additional quantisation levels which enables improved radiometric resolution. The calibration of all types of CCD cameras is necessary in order to characterize the geometry of the sensors and lenses. A number of different types of CCD cameras have been calibrated a the NASA Langley Research Center using self calibration and a small test object. The results of these calibration tests will be described, with particular emphasis on the differences between standard CCD video cameras and scientific slow scan CCD cameras.
    Keywords: Instrumentation and Photography
    Type: First Australian Photogrammetric Conference; Nov 07, 1991 - Nov 09, 1991; Sydney; Australia
    Format: application/pdf
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