Please use this identifier to cite or link to this item: http://hdl.handle.net/11400/4986
Title: Estimation of camera parameters from stereo pairs with no external control information
Authors: Καλησπεράκης, Ηλίας
Καρράς, Γιώργος
Πέτσα, Έλλη
Item type: Conference publication
Conference Item Type: Full Paper
Keywords: Calibration;Orientation;Bundle;Lens Distortion;Precision;Βαθμονόμηση;Προσανατολισμός;Δέσμη;Φακός παραμόρφωσης;Ακρίβεια
Subjects: Technology
Photogrammetry
Τεχνολογία
Φωτογραμμετρία
Issue Date: 28-Jan-2015
27-Sep-2005
Date of availability: 28-Jan-2015
Abstract: Leaving planar rectification aside, in most practical cases of architectural photogrammetry – where mostly non-metric cameras are now used – the camera interior orientation must be known. Of course, it is infeasible to anticipate every possible case and calibrate in advance all available (including auto-focus and zoom) lenses. Therefore, tools are required for the on-the-job estimation of interior orientation parameters. This paper focuses on the simplest instances, namely when no ground control is available. To this end, there exist both single-image methods (for images with clearly defined vanishing points) as well as a multi-image approaches (self-calibra-ting bundle adjustment which, in principle, also allows estimating the camera interior parameters without exterior information). Most applications, however, still rely on the stereo pair. Thus, the question of determining camera parameters solely from point correspon-dences on two images is addressed here. Indeed, it is known that simple point homologies in uncalibrated stereo pairs can impose the epipolar constraint, expressed by the ‘fundamental matrix’ (well documented in computer vision literature), and even permit partialself-calibration. For instance, the camera constant of normal cameras – even if different for the two images – may be recovered if the principal point is assumed to be known. Several non-iterative algorithms have also been presented for computing one or two camera constants (the principal point can, too, be localized for given camera constants). The pertinent critical configurations have also been studied. In this contribution, the specific question of estimating a common camera constant is treated. After using a linear algorithm for obtaining initial values, bundle adjustment of the stereo pair is performed for the estimation of relative orientation together with the camera constant as well as radial lens distortion. Relying on extensive real data, the performance of this approach for partial self-calibration without external information is assessed against full self-calibrating bundle adjustment with control points. A comparison of the accuracy of 3D reconstructions with the two methods indicates that the investigated approach is capable of providing compar-able results. Further tests are still needed, however, focusing on issues such as proximity to critical geometries or the effect of noise.
Language: English
Citation: Kalisperakis, I., Karras, G. and Petsa, E. (2005). Estimation of camera parameters from stereo pairs with no external control information. Proc. XX CIPA International Symposium, Torino, 27/9- 1/10/2005, pp. 390-394. Available from: http://portal.survey.ntua.gr/main/labs/photo/staff/gkarras/Karras_Cipa_2005b.pdf
Conference: XX CIPA International Symposium
Access scheme: Publicly accessible
License: Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ηνωμένες Πολιτείες
URI: http://hdl.handle.net/11400/4986
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