The handheld target greatly expands the fields of the vision measurement systems. However, it introduces extraction errors and position errors, which degrades the positioning precision of the vision measurement systems. In order to evaluate the influence of the handheld targets on the accuracy of T-VMS, we first analyzed the positioning principle of the visual measurement system and established the precision model under two typical structures of the T-VMS. We then studied the extraction errors and position errors introduced by the handheld targets and quantified the errors. Finally, we discussed the influence of the said errors on the positioning in 3D space with system precision model. We applied the precision model in an actual T-VMS to confirm its feasibility and effectiveness, and found that it indeed estimate the errors introduced by the handheld targets effectively.
Phase unwrapping is a significant procedure that has raised a great interest in many coherent imaging systems. What we believe to be a new phase unwrapping algorithm, is described and tested. The method starts from the fact that 2D wrapped phase distribution can be regarded as a response to two orthogonal 1D direction excitation signals. This suggests a cepstrum analysis to be implemented in the phase unwrapping problem. Experimental results both from the fringe projection profilometry and DENSE MRI also confirmed the validity of our approach. In fact, this proposed method is possible to attain a fast and practical phase unwrapping solution with enhanced noise robustness.