- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Extrinsic Camera Calibration of Display-Camera System with Cornea Reflections
摘要： In this paper, we propose a novel method to extrinsically calibrate a camera to a 3D reference object that is not directly visible from the camera. We use a human cornea as a spherical mirror and calibrate the extrinsic parameters from the re?ections of the reference points. The main contribution of this paper is to present a cornea-re?ection-based calibration algorithm with a simple con?guration: ?ve reference points on a single plane and one mirror pose. In this paper, we derive a linear equation and obtain a closed-form solution of extrinsic calibration by introducing two ideas. The ?rst is to model the cornea as a virtual sphere, which enables us to estimate the center of the cornea sphere from its projection. The second is to use basis vectors to represent the position of the reference points, which enables us to deal with 3D information of reference points compactly. We demonstrate the performance of the proposed method with qualitative and quantitative evaluations using synthesized and real data.
关键词： spherical mirror,cornea re?ection,camera calibration
更新于2025-09-09 09:28:46
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An effective method for camera calibration in defocus scene with circular gratings
摘要： Conventional camera calibrations with circular patterns always require sharp target images and thus fail if the images are blurred. In this paper, we present an effective calibration approach using three circular gratings, which can be employed in defocus scene. Rather than using the concentric circles as the targets, the proposed method utilizes circular gratings generated by phase-shifting methods. The intrinsic parameters of the camera can be obtained with the images of circular points, and it works even if the camera is out-of-focus. Numerical simulation and real data experiments have been carried out to validate the method. And the results show that our method can calibrate the camera effectively even under severe defocus. Moreover, the entire process requires no metric measurement of the test pattern, which is very flexible to implement and suitable for people who are not familiar with computer vision.
关键词： Phase-shifting,Camera calibration,Defocus,Concentric circles
更新于2025-09-09 09:28:46
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A Robust and Rapid Camera Calibration Method by One Captured Image
摘要： A robust and rapid camera calibration method is essential in vision measurement. This paper proposes a camera calibration method using a 2.5-D coding target that requires just a single captured image and is capable of identifying the intrinsic and extrinsic parameters of a camera system simultaneously. The calibration target consists of four fixed planes to which coded patterns are attached. The fixed planes of the target prevent the ill condition that arises in Zhang’s method, and they provide four different homography matrices at the same time. The extrinsic parameters of the cameras are calculated using the geometric constraints of the feature circles on each plane. The coded pattern allows the four planes to be distinguished automatically. The proposed method is first verified by comparison experiments with three classical calibration methods. The results confirm that the proposed method has the greatest accuracy and smallest variance of errors. The influences on the calibration results of geometric parameters such as the dihedral angle and the area ratio of the feature circles are then investigated by systematic experiments. This proposed camera calibration method using a single captured image represents a breakthrough in a camera calibration technology and has a broad potential for application to machine vision and vision measurement.
关键词： Camera calibration,target,ill-conditioned system,rapid,robust
更新于2025-09-04 15:30:14