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arXiv 2403.01263cs.CV
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带无模型畸变校正的单图像相机标定

Single-image camera calibration with model-free distortion correction

School of Engineering, University of Basilicata(巴西利卡塔大学工程学院)

Katia Genovese

AI总结:

针对传统相机标定方法存在边界畸变校正差、内参易算错的问题,提出基于单幅散斑靶图像、结合数字图像相关的无模型标定方法,可获取全图密集畸变图,性能优于传统方法且能揭示多图平均掩盖的成像特征。

摘要:

相机标定是需要精确量化测量的计算机视觉应用中至关重要的过程。由Zhang提出的主流方法依赖于拍摄多个位姿下的平面基准点网格的大量图像。尽管该方法灵活且易于实现,但仍存在一些局限性:对包含预定义畸变模型系数在内的整套参数进行同步优化,即使重投影误差相当小,也可能导致图像边界处的畸变校正效果不佳,或造成内参计算失误。事实上,涉及图像拼接的应用(例如多相机系统)需要精确的畸变映射,直至图像的最边缘区域。此外,内参会影响相机位姿估计的准确性,这对于机器人导航中的视觉伺服、自动化装配等应用至关重要。本文提出了一种从覆盖整个传感器的平面散斑图案的单幅图像中估计全套标定参数的方法。图像点与标定靶上物理点之间的对应关系通过数字图像相关(Digital Image Correlation)方法获取。在预先评估主点之后,分别计算有效焦距和外参。在该流程的最后,可得到覆盖整幅图像的密集、均匀的无模型畸变图。研究采用不同噪声水平的合成数据测试了所提方法的可行性,并将其计量性能与Zhang的方法进行了对比。真实场景测试表明,该方法能够揭示被多图像平均效应所掩盖的成像过程特征。

英文摘要:

Camera calibration is a process of paramount importance in computer vision applications that require accurate quantitative measurements. The popular method developed by Zhang relies on the use of a large number of images of a planar grid of fiducial points captured in multiple poses. Although flexible and easy to implement, Zhang's method has some limitations. The simultaneous optimization of the entire parameter set, including the coefficients of a predefined distortion model, may result in poor distortion correction at the image boundaries or in miscalculation of the intrinsic parameters, even with a reasonably small reprojection error. Indeed, applications involving image stitching (e.g. multi-camera systems) require accurate mapping of distortion up to the outermost regions of the image. Moreover, intrinsic parameters affect the accuracy of camera pose estimation, which is fundamental for applications such as vision servoing in robot navigation and automated assembly. This paper proposes a method for estimating the complete set of calibration parameters from a single image of a planar speckle pattern covering the entire sensor. The correspondence between image points and physical points on the calibration target is obtained using Digital Image Correlation. The effective focal length and the extrinsic parameters are calculated separately after a prior evaluation of the principal point. At the end of the procedure, a dense and uniform model-free distortion map is obtained over the entire image. Synthetic data with different noise levels were used to test the feasibility of the proposed method and to compare its metrological performance with Zhang's method. Real-world tests demonstrate the potential of the developed method to reveal aspects of the image formation that are hidden by averaging over multiple images.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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