6 research outputs found
Inertia compensation while scanning screw threads on coordinate-measuring machines
Usage of scanning coordinate-measuring machines for inspection of screw
threads has become a common practice nowadays. Compared to touch trigger
probing, scanning capabilities allow to speed up measuring process while still
maintaining high accuracy. However, in some cases accuracy drasticaly depends
on the scanning speed. In this paper a compensation method is proposed allowing
to reduce the influence of some dynamic effects while scanning screw threads on
coordinate-measuring machines
Design and verification of diffractive optical elements for speckle generation of 3-D range sensors
The optical projection using speckles is one of the structured light methods that have been applied to three-dimensional (3-D) range sensors. This paper investigates the design and fabrication of diffractive optical elements (DOEs) for generating the light field with uniformly distributed speckles. Based on the principles of computer generated holograms, the iterative Fourier transform algorithm was adopted for the DOE design. It was used to calculate the phase map for diffracting the incident laser beam into a goal pattern with distributed speckles. Four patterns were designed in the study. Their phase maps were first examined by a spatial light modulator and then fabricated on glass substrates by microfabrication processes. Finally, the diffraction characteristics of the fabricated devices were verified. The experimental results show that the proposed methods are applicable to the DOE design of 3-D range sensors. Furthermore, any expected diffraction area and speckle density could be possibly achieved according to the relations presented in the paper