Sensor-aided camera calibration for three dimensional digital image correlation measurements
Sensor-aided camera calibration for three dimensional digital image correlation measurements
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DOI：
10.1117/12.2657163
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发表时间：
2023-04
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影响因子：
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通讯作者：
Fabio Bottalico;Nicholas A. Valente;C. Niezrecki;Kshitij Jerath;Yan Luo;A. Sabato
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文献类型：
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作者：
Fabio Bottalico;Nicholas A. Valente;C. Niezrecki;Kshitij Jerath;Yan Luo;A. Sabato
立体视觉系统通过对两个同步摄像机采集的图像进行处理，可以提取结构物的全场三维位移。为了获得准确的测量结果，必须对相机进行校准，以考虑镜头变形(即内部参数)并计算相机的相对位置和方向(即外部参数)。传统上，通过用两个相机拍摄校准对象(例如，棋盘)的照片来执行校准。由于校准对象的大小必须与目标结构相似，因此在大型结构上进行测量是非常不现实的。该研究提出了一种由三个惯性测量单元和一个激光测距仪组成的多传感器板来计算立体视觉系统的外部参数，并简化了标定过程。本文将基于传感器的定标方法与传统的基于图像的定标方法进行了性能比较。实验室实验表明，与用传统方法标定的摄像机相比，用多传感器板标定的摄像机测量位移的准确率达到95%。研究结果表明，基于传感器的方法可以提高三维数字图像相关测量对大型结构物的适用性，同时减少了标定的时间和复杂性。
Stereovision systems can extract full-field three-dimensional (3D) displacements of structures by processing the images collected with two synchronized cameras. To obtain accurate measurements, the cameras must be calibrated to account for lens distortion (i.e., intrinsic parameters) and compute the cameras’ relative position and orientation (i.e., extrinsic parameters). Traditionally, calibration is performed by taking photos of a calibration object (e.g., a checkerboard) with the two cameras. Because the calibration object must be similar in size to the targeted structure, measurements on large-scale structures are highly impractical. This research proposes a multi-sensor board with three inertial measurement units and a laser distance meter to compute the extrinsic parameters of a stereovision system and streamline the calibration procedure. In this paper, the performances of the proposed sensor-based calibration are compared with the accuracy of the traditional image-based calibration procedure. Laboratory experiments show that cameras calibrated with the multi-sensor board measure displacements with 95% accuracy compared to displacements obtained from cameras calibrated with the traditional procedure. The results of this study indicate that the sensor-based approach can increase the applicability of 3D digital image correlation measurements to large-scale structures while reducing the time and complexity of the calibration.