High-precision dynamic real-time 360-degree omnidirectional point cloud acquisition method based on fringe projection

A high-precision dynamic real-time 360-degree omnidirectional point cloud acquisition method based on fringe projection, comprising the steps of:

• step_1:
• building a quad-camera fringe projection system based on a stereo phase unwrapping (SPU) method, and completing a system calibration;
• step_2:
• obtaining an absolute phase of an object, so as to realize an acquisition of real-time high-precision 3D data under a single viewing angle of the object;
• step_3:
• in a coarse registration thread, using a scale-invariant feature transformation (SIFT) method to obtain 2D matching points of adjacent images, and realizing the coarse registration based on a simultaneous localization and mapping (SLAM) technology by solving a “perspective n-point” (PnP) problem, and at the same time quantifying an amount of motion of the object during each coarse registration;
• and
• step_4:
• in a fine registration thread, in response to an accumulated motion amount of the coarse registration reaching a threshold, performing a fine registration based on a closest point iterative (ICP) method,
• wherein the step 2 further comprises the sub-steps of:
• projecting, by a projector, three-step phase-shifting fringe patterns to the object and simultaneously capturing three-step phase-shifting fringe images by using a plurality of cameras;
• obtaining a wrapped phase of the object from three-step phase-shifting fringe images captured by a first camera of the plurality of cameras;
• and
• obtaining the absolute phase of the object only through three-step phase-shifting fringe images captured by the plurality of cameras,
• wherein the step 3 further comprises the sub-steps of:
• finding the 2D matching points of the adjacent images by assuming two adjacent 3D frames;
• optimizing the 2D matching points by using 3D information;
• obtaining rotation and translation matrices between adjacent 3D frames;
• and
• quantifying an amount of motion in each coarse registration, and
• wherein the step 4 further comprises the sub-steps of:
• comparing a cumulative motion of coarse registration and a size of a motion threshold to determine whether the fine registration can be performed;
• and
• performing the fine registration.