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Precise radial un-distortion of images
- In: Proc. the 17th Int. Conf. on Pattern Recognition (ICPR’04
, 2004
"... Radial image distortion is a frequently observed defect when using wide angle, low focal length lenses. In this pa-per a new method for its calibration and removal is pre-sented. An inverse distortion model is derived that is ac-curate to a sub-pixel level, over a broad range of distor-tion levels. ..."
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Cited by 25 (1 self)
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Radial image distortion is a frequently observed defect when using wide angle, low focal length lenses. In this pa-per a new method for its calibration and removal is pre-sented. An inverse distortion model is derived that is ac-curate to a sub-pixel level, over a broad range of distor-tion levels. An iterative technique for estimating the models parameters from a single view is also detailed. Results on simulated and real images clearly indicate significantly im-proved performance compared to existing methods. 1.
A mapping and localization framework for scalable appearance-based navigation
- COMPUTER VISION AND IMAGE UNDERSTANDING 113 (2009) 172–187
, 2009
"... ..."
More Accurate Camera and Hand-Eye Calibrations with Unknown Grid Pattern Dimensions
- in Proceedings of the IEEE International Conference on Robotics and Automation ICRA
, 2008
"... Abstract — This paper presents two novel approaches for accu-rate intrinsic and extrinsic camera calibration. The rationale be-hind them is the widespread violation of the traditional assump-tion that the metric structure of the calibration object is perfectly known. A novel formulation parameterize ..."
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Cited by 6 (1 self)
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Abstract — This paper presents two novel approaches for accu-rate intrinsic and extrinsic camera calibration. The rationale be-hind them is the widespread violation of the traditional assump-tion that the metric structure of the calibration object is perfectly known. A novel formulation parameterizes a checkerboard cali-bration pattern in such a way that the calibration performs op-timally irrespective of its actual dimensions. Simulations and ex-periments show that it is very rare for traditional calibration me-thods to come by the accuracy readily attained by this approach. I.
Rational radial distortion models of camera lenses with analytical solution for distortion correction
- International Journal of Information Acquisition
, 2004
"... Received (to be inserted by publisher) The common approach to radial distortion is by the means of polynomial approximation, which introduces distortion-specific parameters into the camera model and requires esti-mation of these distortion parameters. The task of estimating radial distortion is to f ..."
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Cited by 5 (1 self)
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Received (to be inserted by publisher) The common approach to radial distortion is by the means of polynomial approximation, which introduces distortion-specific parameters into the camera model and requires esti-mation of these distortion parameters. The task of estimating radial distortion is to find a radial distortion model that allows easy undistortion as well as satisfactory accuracy. This paper presents a new class of rational radial distortion models with easy analytical undistortion formulae. Experimental results are presented to show that with this class of rational radial distortion models, satisfactory and comparable accuracy can be achieved.
Point-less Calibration: Camera Parameters from Gradient-Based Alignment to Edge Images
"... Point-based targets, such as checkerboards, are often not practical for outdoor camera calibration, as cameras are usually at significant heights requiring extremely large calibration patterns on the ground. Fortunately, it is possible to make use of existing non-point landmarks in the scene by form ..."
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Cited by 2 (0 self)
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Point-based targets, such as checkerboards, are often not practical for outdoor camera calibration, as cameras are usually at significant heights requiring extremely large calibration patterns on the ground. Fortunately, it is possible to make use of existing non-point landmarks in the scene by formulating camera calibration in terms of image alignment. In this paper, we simultaneously estimate the camera intrinsic, extrinsic and lens distortion parameters directly by aligning to a planar schematic of the scene. For cameras with square pixels and known principal point, finding the parameters to such an image warp is equivalent to calibrating the camera. Overhead schematics of many environments resemble edge images. Edge images are difficult to align using image-based algorithms because both the image and its gradient are sparse. We employ a ‘long range’ gradient which enables informative parameter updates at each iteration while maintaining a precise alignment measure. As a result, we are able to calibrate our camera models robustly using regular gradient-based image alignment, given an initial ground to image homography estimate. 1.
