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No description available.

No description available.

A three-beam lateral shearing interferometer has been developed. The three-beam shearing interferograms consist of two sets of fringes, one of which acts as a carrier whose intensity is modulated by the second set. The depth of modulation is directly proportional to the phase difference between the middle beam and the outer beams. Phase errors on the order of π/2 cause every other fringe to go from complete dark to complete bright. Therefore, phase errors much smaller than π/2 can be detected. The three-beam interferometer is implemented in three ways: (1) thin film thickness measurement, (2) surface roughness measurement, and (3) surface figure measurement. The three-beam interferometer implemented to measure thin film thickness and surface roughness is accurate to 25 Å. Surfaces with different microstructure are characterized. We have found that each of those surfaces may have one or more of the following: (1) random roughness, (2) slow waviness, and/or (3) periodic structure. The three-beam interferometer is also implemented for testing optical surfaces. The three-beam interferometer is more capable in detecting small zonal errors than the two-beam interferometer. Three-beam interferograms of different surfaces are produced and analyzed. The three-beam interferometer has many advantages: (1) it is a stable, common path interferometer, (2) white light can be instead of coherent light to get rid of the effects of speckle and dust particles, and (3) it is a very low cost interferometer.

Roughness is a relatively untouched field considering its significance to natural scientists. In this thesis mathematical techniques for measuring the roughness of signals are constructed and investigated. Both one dimensional and two dimensional signals are tackled. Applications include geological profiles and biological surfaces. Mathematical techniques include Fourier and Wavelet Transforms. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

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

D.Ing. / The quantification of the surface roughness in order to determine the shear behaviour of rock joints has been performed using many approaches, amongst which the most important are the joint roughness coefficient, statistical methods and the fractal approach. None of these approaches explicitly considers the contribution of grain size to the creation of surface roughness. An investigation has been undertaken to determine whether the grain size may be related to the surface roughness characteristics and also to assess its impact on the shear behaviour of rock joints. The influence of grain size on the shear behaviour of rock joints has been experimentally and numerically studied using a profile measurement approach followed by shear tests in the laboratory. Fresh rock joints in model material made of aggregates of no rite in resin and two natural rock types, namely norite and sandstone, were used for the investigation. A numerical analysis of the study has been performed using the Particle Flow Code PFC20 • Investigation of the model material has resulted in the conceptualisation of grain size parameters. Of the proposed grain size parameters, the average particle size index As has been successfully used to define the particle size distribution of a rock joint for both physical and numerical tests. From the profile measurements, four roughness parameters, n~mely the average inclination angle I, the root mean square of the first derivative Z2, the modified root mean square of the first derivative Z2' and the fractal dimension D, have been computed and a regression analysis conducted. Physical and numerical results have demonstrated that grain size distribution, expressed in terms of average particle size index As shows a good correlation respectively with the root mean square ofthe first derivative Z2, and its modified version Z2'. The root mean square of the first derivative Z2, and the modified root mean square of the first derivative Z2' increase with the average particle size index As. However, no correlation has been found between the grain size parameter and the fractal dimension D or the average inclination angle I. It has also been found that the joint roughness coefficient JRC and the peak friction angle ~P correlate very well with the average particle size index As. The greater the average particle grain size the higher the joint roughness coefficient JRC and the peak friction angle ~p· The type of correlation between JRC and ~P with As depends on the rock type. Exponential shear strength model has been derived where the average particle size index As is related to the peak friction angle via the residual friction angle ~r·

When a polymer film is deposited onto a roughened substrate, the film masks over the underlying substrate roughness. Then when attempting to measure the roughness of the polymer film surface using a stylus-type profile meter, the pressure between the tip of the stylus and the film is sufficient to plastically deform the polymer surface. The result is a possible erroneous measurement of the surface roughness of the polymer film. This thesis reports on attempts to quantify the actual roughness of the polymer film from the measurement obtained by the profile meter. Extensive surface profile data were collected and analyzed to determine the characteristics of the surface of the substrate and of the coating on the substrate. The tracks made by the stylus in the film were then observed in a scanning electron microscope, from which the depth of the stylus tracks were measured. The effects of the film thickness, stylus traversing speed, and substrate roughness on the stylus penetration depth, the variation in the depth, and the measured film roughness are assessed and discussed. It was found that using the fastest stylus traversing speed minimizes the variation of the stylus penetration depth and thus results in the most accurate measurement of the film surface. To predict this stylus indentation depth, a plane strain plastic deformation model is developed using slip-line field theory. It is found that the slip-line model gives good estimates of the stylus indentation depth when the film thickness is large. / Master of Science

Traditionally, surface topography measurement was in the domain of quality control of engineering parts. With the advancement of manufacturing technology and affordable computational costs, different types of surfaces are produced with varied shapes and surface textures. These pose significant measurement problems, therefore, surface topography research is gaining momentum to achieve a better control of the surface. Coherence scanning interferometry (CSI) is one of the most common techniques used for measurement of surface topography. It is preferred over tactile and other non-contact techniques since it provides fast and accurate measurement with high vertical (~ 1 nm) and lateral (~1 μm) resolutions over larger areas without any damage to the surface. Essentially, CSI is treated as one dimensional (1D) superposition of the light waves from an object and a reference that generates a three dimensional (3D) interferogram. Secondly, despite the advantages, there is no standard configuration of CSI that can provide absolute surface topography measurement of an engineering part with multiple materials. An effective solution to this problem will be particularly useful in the field of semiconductor and bio-related industries where chips and instruments are made of many materials. In this Thesis, first, the CSI technique is analysed in terms of a wider theoretical framework of 3D linear filtering technique which shows the similarities among other seemingly disparate techniques such as confocal and optical coherence tomography. Due consideration to the spectral characteristic of the source and the effect of numerical aperture are given and important parameters such as vertical and lateral resolutions are computed to compare this theory with standard analysis methods. Additionally, it is shown that the 3D fringe pattern can be considered to be a superposition of a reference field and the scattered field from the top foil-like layer on the top the object. The scattered field from this foil object is dependent on the normal Fresnel reflection coefficients. Therefore, it explains the phase offset and the proportional height offset introduced by different materials, especially, metals. In an object, where multiple materials are present, each material introduces different phase to the fringe pattern and therefore, the surface topography of the entire object is altered. To overcome this problem, the optical polarising properties of the material are exploited. A novel configuration of polarisation sensitive CSI is presented where interferograms with orthogonal circular polarisations are recorded and analysed. The configuration, initially, needs to be calibrated with a material and after that at each point on the object, the refractive index and height offset can be calculated. Therefore, it can be dually used to identify unknown materials present on the object and also to compensate for the height offset introduced by each material to produce absolute surface topography of the entire object. The configuration provides good agreement with ellipsometric results for metals. Additionally, it retains the advantages of high vertical and lateral resolution same as other standard coherence scanning interferometers.

With the growing trend in use of 3D laser scanning technology for data collection, it is important to study the various potential applications of this revolutionary technology. One such application is the measurement of road roughness at both large and small scales. At larger extents, terrestrial laser scanning (TLS) is compared to several current techniques to measure road profiles including digital levels, inclinometers, and inertial profilers. An overall indicator of roughness (e.g. International Roughness Index, IRI) can be obtained from these road profiles and is used by state DOTs to determine the pavement quality. Since TLS is able to collect a large, dense set of data relatively quickly, this technology could provide states with an additional tool to both measure pavement roughness and collect data for the entire roadway. TLS has the added benefit of being able to generate multiple profiles across the roadway efficiently. At a fine scale, micron resolution 3D laser scanners can be utilized to determine the influence of asphalt mix designs on the roughness of the pavement. Of particular interest is the selection of predominant aggregate size within the mix. Results showed that TLS can determine pavement profiles and comparable IRI results to those from current methods. The elevation values collected within the profile were accurate within expected ranges. However, cross correlations, which take into account the location of the roughness, were poor, indicating that TLS is not an effective method to determine a reference profile. TLS was used to determine the cross slopes across the roadway, something that cannot be done with data from an inclinometer or inertial profiler. / Graduation date: 2012 / Zipped file contains 4 file types. Excel files (.xlsx and .xls) can be opened using Microsoft Excel. OBJ files (.obj) are geometry definition file formats intended to be imported into a software program to manipulate 3D laser scans and can also be opened using Notepad++ or another powerful text editor. Notepad++ is freely available for download on the Web. PVP files (.pvp) are project files that contain project settings and profile data and can be opened with ProVAL, a freely available engineering software application used to view and analyze roadway profiles. ERD files (.ERD) are standard file formats used for storing numbers in tabular form and can be opened with Notepad++ or another powerful text editor. These files contain roadway profiles and are designed to be imported into ProVAL.