Fringe pattern profilometry using triangular patterns and intensity ratios is a robust and computationally efficient method in three-dimensional shape measurement technique. However, similar to other multiple-shot techniques, the object must be kept static during the process of measurement, which is a challenging requirement for the case of fast-moving objects. Errors will be introduced if the traditional multiple-shot techniques are used directly in the measurement of a moving object. A new method is proposed to address this issue. First, the movement of the object is measured in real time and described by the rotation matrix and translation vector. Then, the expressions are derived for the fringe patterns under the influence of the two-dimensional movement of the object, based on which the normalized fringe patterns from the object without movement are estimated. Finally, the object is reconstructed using the existing intensity ratio algorithm incorporating the fringe patterns estimated, leading to improved measurement accuracy. The performance of the proposed method is verified by experiments.
Phase shifting profilometry (PSP) technique is widely used as a 3-D shape measurement technique due to its robustness
and accuracy. However, PSP requires multiple fringe pattern images to be projected onto an object and a reference plane
to calculate the phase value, and also the object must maintain motionless when the measurement is taken. If the object
moves during the measurement, significant errors will be introduced when calculating the phase value. This paper
analyses the relationship between the object movement and the phase value, and proposes a method for compensating the
errors caused by two-dimensional movement of object. This method can eliminate the errors caused by two-dimensional
movement of object and reconstruct the object shape successfully. The effectiveness of the proposed method is verified