Abstract Structured light measurement system that consists of a camera and a projector has been widely used in three-dimensional (3-D) shape measurement. The premise of measurement is to calibrate the structured light system, and the calibration accuracy directly affects the accuracy of 3-D measurement system. The traditional calibration board-based methods suffer from either complex operations or uncompetitive accuracy. To overcome these limitations, this paper proposes a novel calibration method by introducing a liquid crystal display (LCD) with holographic projection film as a phase target to simplify the operations and improve the speed and accuracy of system calibration. The proposed calibration procedures are given as follows: Firstly, the LCD is turned on and kept still to display the red/blue orthogonal fringe pattern, and it is then turned off to reflect the projected fringe pattern with the holographic projection film, the brightness and frequency of the two patterns are adjusted and captured; Secondly, the accurate absolute phase maps are obtained using optimized phase calculation and overall error compensation method; Finally, the above two steps are repeated at several different positions and orientations in the measured field of view. The one-to-one correspondence between the camera and the projector pixel coordinate system and the phase target world coordinate system is established by using the phase equality, and the intrinsic and extrinsic parameters of the system are obtained to reconstruct 3-D shape of the objects. The experiment results demonstrate that the proposed method is feasible and the equipment is simple, which can effectively reduce the overall error, ensure the synchronous calibration of the camera and the projector, avoid the problem of time-consuming, and eventually improve the accuracy of the system calibration.

中文翻译：

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基于红蓝正交条纹投影的三维测量系统标定方法

摘要 由相机和投影仪组成的结构光测量系统已广泛应用于三维（3-D）形状测量。测量的前提是对结构光系统进行校准，校准精度直接影响3D测量系统的精度。传统的基于校准板的方法要么操作复杂，要么精度不具竞争力。为了克服这些限制，本文提出了一种新的校准方法，通过引入以全息投影薄膜为相位目标的液晶显示器（LCD）来简化操作并提高系统校准的速度和准确性。建议的校准程序如下：首先，打开LCD并保持静止以显示红/蓝正交条纹图案，然后关闭，用全息投影膜反射投影出的条纹图案，调整并捕捉两种图案的亮度和频率。其次，采用优化的相位计算和整体误差补偿方法获得精确的绝对相位图；最后，在被测视场中的几个不同位置和方向重复上述两个步骤。利用相位等式建立相机与投影机像素坐标系与相位目标世界坐标系的一一对应关系，得到系统的内、外参数，重构出物体的3维形状。对象。实验结果表明，该方法可行且设备简单，