A COMPUTATIONAL SPECTRAL IMAGING TECHNIQUE AND ITS APPLICATION IN FORM METROLOGY
1 online resource (121 pages) : PDF
University of North Carolina at Charlotte
Many existing systems for three-dimensional (3D) shape measurement require mechanical moving parts that limit the measurement speed. A non-contact optical system that does not requires any moving parts can, in principle, increase the speed of measurement. This is particularly an important criterion in volume manufacturing of parts. This motivates us to develop a new optical system for 3D shape measurement with emphasize in the capability of such system to be used as a tool for quality control in volume manufacturing. This dissertation describes the design and implementation of a new 3D shape measurement system. The capability of this system is demonstrated on selected samples with varying slopes. The 3D system presented here is based on a new depth-sensitive, multi-focal imaging system that is developed. This novel imaging system is design by intentionally introducing axial chromatic aberration in the lens system of the camera. A computational unit is also developed to analyze images formed by the designed chromatic lens and calculate the form of a 3D object. The application of this system as a spectral imager is also investigated. The algorithms implemented in the camera’s computational unit as well as the design process of the camera’s lens system are described. Simulation and experimental results are provided to evaluate the performance of the spectral imaging camera. The spectral imaging camera has a spectral resolution of 4 nm and spatial resolution of 46 microns. Finally, the experimental results is presented that demonstrate the repeatability of the depth measurements for two measured samples are 11.8 and 10 microns for measurement range of up to 5 mm. These measurements show that the developed system is capable of measuring 3D shape of the object and it is particularly useful if the system is used to measure deviations of parts from the master part used for calibration.
3D SHAPE MEASUREMENTCHROMATIC ABERRATIONDISPERSIVE IMAGING LENS SYSTEMSHAPE FROM DEFOCUSSHAPE FROM FOCUSSPECTRAL IMAGING
Optical Science & Engineering
Davies, AngelaEvans, ChristopherTrammell, SusanSubramanian, Kalpathi
Thesis (Ph.D.)--University of North Carolina at Charlotte, 2017.
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