A new confocal 3-D full-field surface profilometer employing image fibers for digital fringe projection

摘要

The development of a new confocal full-field 3-D surface profilometer using image fibers for digital fringe projection is presented in the article. Three-dimensional measurement systems of high precision have been widely applied in high-technology industries and bio-medical areas, especially for micro-scale accuracy measurement. However, due to bulky volume, most of current surface profilometers cannot easily perform 3-D measurement within a space-restricted or in-field inspection environment. To overcome this limit, a new fiber-embedded coaxial optical configuration employing digital fringe projection for confocal measurement was developed to achieve micro 3-D surface profilometry. Surface profilometry of micro component can be accomplished by the developed profilometer which comprises a digital fringe projection system, a coherent image fiber, a set of optical lenses and an image sensing device. Using the proposed confocal measurement principle, the system can obtain out-of-plane measurement accuracy up to 1.02 micrometers. Some industrial micro components can be successfully measured and reconstructed for 3-D surface models. Verified by some real industrial examples, the developed approach is capable of achieving accurate micro 3-D surface profilometry with a maximum measurement error less than 2% of the overall range.