Camera and projector are the key components of structured light three-dimensional (3-D) measurements, and Digital Light Processing (DLP) projector has been widely used for projecting digital structured light patterns for the measurement. The light projecting of projectors can be modeled as the inverse procedures of camera imaging, and its high-accuracy calibration is still a remaining challenge. Therefore, this paper proposes a novel projector calibration method to improve the calibration accuracy of DLP projector. By fixing the position of the camera and calibration board, this method essentially eliminates the perspective transformation error and effectively avoids the distortion of the extracted marker points. The proposed projector calibration procedures are given as follows: Firstly, the optical axis of the camera is adjusted parallel to the normal of the hollow ring calibration board, and a texture image is captured by the camera; Secondly, the horizontal and vertical fringe patterns with nine different positions and directions are projected onto the calibration board, and nine sets of projected images are taken; Finally, a one-to-one correspondence between the camera and the projector is established, and the projector is accurately calibrated using the phase equivalence. The experimental results show that the proposed projector calibration method is feasible and easy to operate, which can essentially eliminate the perspective transformation error and ensure the competitive accuracy.

中文翻译：

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考虑透视变换的条纹投影轮廓仪高精度投影仪标定方法

相机和投影仪是结构光三维（3-D）测量的关键组件，数字光处理（DLP）投影仪已被广泛用于投影数字结构光图案以进行测量。可以将投影仪的光投射建模为相机成像的逆过程，其高精度校准仍然是一个挑战。因此，本文提出了一种新颖的投影仪校准方法，以提高DLP投影仪的校准精度。通过固定摄像机和校准板的位置，该方法从根本上消除了透视变换误差，并有效避免了提取的标记点的失真。建议的投影仪校准程序如下：首先，调节摄像机的光轴，使其平行于中空环校准板的法线，摄像机捕获纹理图像。其次，将具有九个不同位置和方向的水平和垂直条纹图案投影到校准板上，并获取九组投影图像。最终，在相机和投影仪之间建立了一对一的对应关系，并使用相位等价对投影仪进行了精确校准。实验结果表明，所提出的投影仪标定方法是可行且易于操作的，可以从根本上消除透视变换误差，保证了竞争的准确性。将具有九个不同位置和方向的水平和垂直条纹图案投影到校准板上，并拍摄九组投影图像。最终，在相机和投影仪之间建立了一对一的对应关系，并使用相位等价对投影仪进行了精确校准。实验结果表明，所提出的投影仪标定方法是可行且易于操作的，可以从根本上消除透视变换误差，保证了竞争的准确性。将具有九个不同位置和方向的水平和垂直条纹图案投影到校准板上，并拍摄九组投影图像。最终，在相机和投影仪之间建立了一对一的对应关系，并使用相位等价对投影仪进行了精确校准。实验结果表明，所提出的投影仪标定方法是可行且易于操作的，可以从根本上消除透视变换误差，保证了竞争的准确性。