With the characteristics of un-touching, high-automatic and high-speed, we measured 3D shape by digital moiré patterns. And it can measure 3D shape without compensator, auxiliary mirror, hologram and other assistant modules. So it is widely used in measurement of 3D shape. But with the negative effect of grating area and CCD resolution of the camera, it has some problems in large aperture, steep aspheric surface, even off-axis aspheric testing. Focus on these problems; this paper established a sub-region splicing measurement of aspheric surface by using the combination of digital moire patterns and digital phase shifting technology. This paper also illustrated the basic theory, and the mathematical implementation procedure. In all, sub-region splicing digital moiré patterns can be considered as another method, which beyond compensation tests to measurement of aspheric surface.
A number of investigators have examined moire patterns on precipitate particles in various age-hardening alloys. For example, Phillips has analyzed moire fringes at cobalt precipitates in copper and Von Heimendahl has reported on moire fringes in the system Al-Au. Recently, we have observed moire patterns on impurity precipitates in beryllium quenched in brine from 1000°C and aged at various temperatures in the range of 500-800°C. This heat treatment of beryllium rolled from vacuum cast ingots produces the precipitation of both an fee ternary phase, AlFeBe4, and an hcp binary phase, FeBe11. However, unlike a typical age-hardening alloy, the solute content of this material is low (less than 1000 ppm of Fe and 600 ppm of Al) and hence the total volume fraction of precipitates is small. Therefore there is some difficulty in distinguishing the precipitates and their orientation relationships with the beryllium matrix since the weak precipitate spots generally do not appear on the diffraction patterns.
Vortex dynamics, pinning, and angle-dependent motion on moiré patterns