RT Journal Article
T1 Measurement of surface topography by RGB Shadow-Moiré with direct phase demodulation
A1 Quiroga Mellado, Juan Antonio
A1 Gómez Pedrero, José Antonio
A1 Terrón López, M. José
A1 Crespo Vázquez, Daniel
AB In this paper we present the application of a direct demodulation method for the measurement of surface topography by means of Shadow-Moiré. In our set-up, we use three LEDs (with green, red and blue peak wavelengths) to illuminate the grating. Due to the different position of these light sources, a polychromatic Shadow-Moiré fringe pattern is produced, which can be described as the superposition of three monochromatic (red, green and blue) fringe patterns. Taking the image of this polychromatic fringe pattern with a RGB CCD camera, we get a monochromatic fringe pattern stored at each RGB channel of the CCD. The direct demodulation algorithm employed uses these fringe patterns to calculate the wrapped phase map. After unwrapping the phase map using a standard multi-grid technique, we implemented an automatic procedure to detect the area of interest of the phase map by removing low modulation zones and to calculate the absolute value of the phase. In this way it is possible to determine the topography of a surface with a single RGB snapshot maintaining a simple experimental set-up, which is an important feature, especially for the study of dynamic phenomena such as deformations. We present the experimental results obtained after measuring different objects with both smooth and rough surface textures.
PB Elsevier Sci. Ltd.
SN 0143-8166
YR 2006
FD 2006-12
LK https://hdl.handle.net/20.500.14352/50788
UL https://hdl.handle.net/20.500.14352/50788
LA eng
NO © 2006 Elsevier Ltd. This work has been financially supported by the Spanish Ministry of Science andEducation; project DPI2002-02104.
NO Spanish Ministry of Science and Education
DS Docta Complutense
RD 4 abr 2025