The Research Of Defocusing Fringe Pattern Projection Profilometry On Dynamic Objects

The three-dimensional measurement based on phase-shifting profilometry conducted by fringe pattern projection system is featured by its advantages such as high accuracy and noncontact implementation,but it prefers the static measurement environment when being used.To achieve the fast and high-precision measurement,in recent years,defocusing fringe pattern projection technology has been a research focus,and has even been widely utilized in fast measurements and measurements upon dynamic objects.However,this method is inevitably influenced by the motion of dynamic objects,leading to error in measurement results.In order to correct and compensate for the error,a deep research and analysis over the effects induced by different motions is proposed,and the corresponding solutions are provided as well.The main innovations and work are as follows:(1)A three-dimensional measurement with compensation based on the uniform motion is put forward.The proposed method takes the shifting both on the image plane of the camera and the phase map of the projector into consideration.Supplied with Lucas-Kanade pyramidal optical flow method,our method estimates the motion information on the image plane and then figures out the phase error on the phase map with a 5-step phase-shifting method.Simultaneously,a novel filter to suppress the periodic influence of phase-shifting method as well as the effects of the outliers is proposed in this paper,further improving the measurement accuracy and compensation performance.Moreover,a novel algorithm is designed to correct the error occurring in the phase unwrapping process,fulfilling the compensation for the coding process done by gray code patterns.Simulations and experiments indicate that the proposed method can obviously reduce the motion-induced influence on the phase-shifting profilometry,thus weakening the motion ripples on the reconstruction results.(2)Aiming to cope with the problems in the measurement of objects under non-uniform motion,through calculating the error induced by non-uniform with optimization algorithm,a three-dimensional measurement with compensation for non-uniform motion is proposed.The proposed method is established by expanding the compensation based on the uniform motion,and improves the measurement performance while loosening the limits of the motion state of the objects measured.This method rearranges the projection sequence,making it more robust in practical application.Simulations and experiments reveal that,the given method can achieve results insensitive to motion when measuring objects under non-uniform motion.Moreover,an alternative utilizing facial landmarks is offered for the motion estimation in human face measurement,which can improve the measurement performance on human faces.