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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Extending the measurement range of an optical surface profiler.

Cochran, Eugene Rowland, III. January 1988 (has links)
This dissertation investigates a method for extending the measurement range of an optical surface profiling instrument. The instrument examined in these experiments is a computer-controlled phase-modulated interference microscope. Because of its ability to measure surfaces with a high degree of vertical resolution as well as excellent lateral resolution, this instrument is one of the most favorable candidates for determining the microtopography of optical surfaces. However, the data acquired by the instrument are restricted to a finite lateral and vertical range. To overcome this restriction, the feasibility of a new testing technique is explored. By overlapping a series of collinear profiles the limited field of view of this instrument can be increased and profiles that contain longer surface wavelengths can be examined. This dissertation also presents a method to augment both the vertical and horizontal dynamic range of the surface profiler by combining multiple subapertures and two-wavelength techniques. The theory, algorithms, error sources, and limitations encountered when concatenating a number of profiles are presented. In particular, the effects of accumulated piston and tilt errors on a measurement are explored. Some practical considerations for implementation and integration into an existing system are presented. Experimental findings and results of Monte Carlo simulations are also studied to explain the effects of random noise, lateral position errors, and defocus across the CCD array on measurement results. These results indicate the extent to which the field of view of the profiler may be augmented. A review of current methods of measuring surface topography is included, to provide for a more coherent text, along with a summary of pertinent measurement parameters for surface characterization. This work concludes with recommendations for future work that would make subaperture-testing techniques more reliable for measuring the microsurface structure of a material over an extended region.
2

Height inspection of wafer bumps without explicit 3D reconstruction.

January 2007 (has links)
by Dong, Mei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 83-90). / Abstracts in English and Chinese. / INTRODUCTION --- p.1 / Chapter 1.1 --- Bump Height Inspection --- p.1 / Chapter 1.2 --- Our Height Inspection System --- p.2 / Chapter 1.3 --- Thesis Outline --- p.3 / BACKGROUND --- p.5 / Chapter 2.1 --- Wafer Bumps --- p.5 / Chapter 2.2 --- Common Defects of Wafer Bumps --- p.7 / Chapter 2.3 --- Traditional Methods for Bump Inspection --- p.11 / BIPLANAR DISPARITY METHOD --- p.22 / Chapter 3.1 --- Problem Nature --- p.22 / Chapter 3.2 --- System Overview --- p.25 / Chapter 3.3 --- Biplanar Disparity Matrix D --- p.30 / Chapter 3.4 --- Planar Homography --- p.36 / Chapter 3.4.1 --- Planar Homography --- p.36 / Chapter 3.4.2 --- Homography Estimation --- p.39 / Chapter 3.5 --- Harris Corner Detector --- p.45 / Chapter 3.6 --- Experiments --- p.47 / Chapter 3.6.1 --- Synthetic Experiments --- p.47 / Chapter 3.6.2 --- Real image experiment --- p.52 / Chapter 3.7 --- Conclusion and problems --- p.61 / PARAPLANAR DISPARITY METHOD --- p.62 / Chapter 4.1 --- The Parallel Constraint --- p.63 / Chapter 4.2 --- Homography estimation --- p.66 / Chapter 4.3. --- Experiment: --- p.69 / Chapter 4.3.1 --- Synthetic Experiment: --- p.69 / Chapter 4.3.2 --- Real Image Experiment: --- p.74 / CONCLUSION AND FUTURE WORK --- p.80 / Chapter 5.1 --- Summary of the contributions --- p.80 / Chapter 5.2 --- Future Work --- p.81 / Publication related to this work: --- p.83 / BIBLIOGRAPHY --- p.83

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