Bundle Adjustment With and Without Damping

Börlin, Niclas; Grussenmeyer, Pierre

doi:10.1111/phor.12037

Cited by 34 publications

(39 citation statements)

References 16 publications

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“…Different techniques have been suggested to modify the iteration sequence to improve the convergence properties (see e.g. Lourakis and Argyros, 2009;Börlin and Grussenmeyer, 2013). However, assuming the mathematical problem is well posed, the optimal values returned by a BA procedure should not depend on what particular sequence of computations resulted in those estimates.…”

Section: Iteration Sequencementioning

confidence: 99%

External Verification of the Bundle Adjustment in Photogrammetric Software Using the Damped Bundle Adjustment Toolbox

Börlin¹,

Grussenmeyer²

2016

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:The aim of this paper is to investigate whether the Matlab-based Damped Bundle Adjustment Toolbox (DBAT) can be used to provide independent verification of the BA computation of two popular software -PhotoModeler (PM) and PhotoScan (PS). For frame camera data sets with lens distortion, DBAT is able to reprocess and replicate subsets of PM results with high accuracy. For lens-distortion-free data sets, DBAT can furthermore provide comparative results between PM and PS. Data sets for the discussed projects are available from the authors. The use of an external verification tool such as DBAT will enable users to get an independent verification of the computations of their software. In addition, DBAT can provide computation of quality parameters such as estimated standard deviations, correlation between parameters, etc., something that should be part of best practice for any photogrammetric software. Finally, as the code is free and open-source, users can add computations of their own.

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Section: Iteration Sequencementioning

confidence: 99%

External Verification of the Bundle Adjustment in Photogrammetric Software Using the Damped Bundle Adjustment Toolbox

Börlin¹,

Grussenmeyer²

2016

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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“…The classical least-squares adjustment performed during the bundle adjustment process corresponds to the undamped Gauss-Newton optimization method [40]. However, several factors such as the absence of appropriate initial values or the low intersection angles between the images may prevent the iterative solution from reaching convergence [41].…”

Section: Bundle Adjustmentmentioning

confidence: 99%

“…However, several factors such as the absence of appropriate initial values or the low intersection angles between the images may prevent the iterative solution from reaching convergence [41]. Several damping methods may be applied in order to optimize the results [40,42].…”

Section: Bundle Adjustmentmentioning

confidence: 99%

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Open Source and Independent Methods for Bundle Adjustment Assessment in Close-Range UAV Photogrammetry

Murtiyoso

Grussenmeyer

Börlin

et al. 2018

Drones

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Close-range photogrammetry as a technique to acquire reality-based 3D data has, in recent times, seen a renewed interest due to developments in sensor technologies. Furthermore, the strong democratization of UAVs (Unmanned Aerial Vehicles) or drones means that close-range photogrammetry can now be used as a viable low-cost method for 3D mapping. In terms of software development, this led to the creation of many commercial black-box solutions (PhotoScan, Pix4D, etc.). This paper aims to demonstrate how the open source toolbox DBAT (Damped Bundle Adjustment Toolbox) can be used to generate detailed photogrammetric network diagnostics to help assess the quality of surveys processed by the commercial software, PhotoScan. In addition, the Apero module from the MicMac software suite was also used to provide an independent assessment of the results. The assessment is performed by the careful examination of some of the bundle adjustment metrics generated by both open source solutions. A UAV project was conducted on a historical church in the city center of Strasbourg, France, in order to provide a dataset with a millimetric level of precision. Results showed that DBAT can be used to reprocess PhotoScan projects under similar conditions and derive useful metrics from them, while Apero provides a completely independent verification of the results of commercial solutions. Overall, this paper shows that an objective assessment of photogrammetric results is important. In cases where problems are encountered in the project, this assessment method can be useful to detect errors that may not be explicitly presented by PhotoScan.

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“…We investigate a procedure where the focal length is the only parameter that is given a specific initial value; the other parameters are given standard initial values or computed from the data. Our target is to investigate the pull-in range of this procedure using the set of bundle adjustment techniques available in the free Damped Bundle Adjustment Toolbox for Matlab, described in Börlin and Grussenmeyer (2013a), and to suggest a 1 http://www.vision.caltech.edu/bouguetj/calib doc 2 http://www.mathworks.com/products/computer-vision standardised procedure that does not require any camera knowledge.…”

Section: Introductionmentioning

confidence: 99%

Camera Calibration using the Damped Bundle Adjustment Toolbox

Börlin

Grussenmeyer

2014

ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:Camera calibration is one of the fundamental photogrammetric tasks. The standard procedure is to apply an iterative adjustment to measurements of known control points. The iterative adjustment needs initial values of internal and external parameters. In this paper we investigate a procedure where only one parameter -the focal length is given a specific initial value. The procedure is validated using the freely available Damped Bundle Adjustment Toolbox on five calibration data sets using varying narrow-and wide-angle lenses. The results show that the Gauss-Newton-Armijo and Levenberg-Marquardt-Powell bundle adjustment methods implemented in the toolbox converge even if the initial values of the focal length are between 1/2 and 32 times the true focal length, even if the parameters are highly correlated. Standard statistical analysis methods in the toolbox enable manual selection of the lens distortion parameters to estimate, something not available in other camera calibration toolboxes. A standardised camera calibration procedure that does not require any information about the camera sensor or focal length is suggested based on the convergence results. The toolbox source and data sets used in this paper are available from the authors.

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Bundle Adjustment With and Without Damping

Cited by 34 publications

References 16 publications

External Verification of the Bundle Adjustment in Photogrammetric Software Using the Damped Bundle Adjustment Toolbox

External Verification of the Bundle Adjustment in Photogrammetric Software Using the Damped Bundle Adjustment Toolbox

Open Source and Independent Methods for Bundle Adjustment Assessment in Close-Range UAV Photogrammetry

Camera Calibration using the Damped Bundle Adjustment Toolbox

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