As the electronic industry advances rapidly, the dimensions of the semiconductor products keep on being shrunk and that leads to more stringent requirement on process control and quality assurance. In particular, area array packages like BGA, CSP, flip chips, wafer bumping and wafer-level packaging need to have the 3D quality of some micro-surfaces inspected accurately and efficiently. An example of the micro-surfaces is the solder bumps for direct die-to-die bonding, which are of size as small as 60 to 600 microns in diameter. However, the tiny size and often highly specular and textureless nature of the surfaces make the inspection difficult. In addition, the size of the inspection system is required to be small so as to minimize restraint, on the operation of the various moving parts involved in the manufacturing process. / Experimental results with image data of a variety of objects have positively demonstrated the feasibility of the proposed methodology. / In the mechanism the inspection speed is governed by the number of needed images which also equals the number of spatial shiftings of the grating. This thesis also addresses how the grating, as well as its spatial shifting, can be designed optimally for minimizing this image number for faster inspection speed. An optimal solution to shifting strategy optimization is proposed that is applicable to any pattern on the fringe grating. A design method is also introduced for optimal pattern design, which has higher efficiency than brute-force searching. To reduce image number furthermore, bit-pairing codification mechanism and color-encoded pattern are proposed and verified to be more efficient. / In this thesis, I propose a new methodology for reconstructing micro-surfaces in 3D. The mechanism is based upon the familiar concept of binary structured-light, projection, but adapted, for the purpose of greatly reducing the system size, from the traditional setup of an array of multiple light sources to one with a single light source. The mechanism consists of a single light source in combination with a binary grating for projecting a binary pattern onto the target surface, and of a camera for capturing image of the illuminated scene. By shifting the binary grating in space and in every drifting taking a separate image of the illuminated surface, each position on the illuminated surface will be attached with a string of binary code over the sequence of captured images. With a suitable design of the binary grating, the binary code string can be made unique for each bump surface position, allowing exact correspondence between the binary pattern and image data, and subsequently 3D determination through triangulation. With such a bright-or-dark world for each image position, the issues of image saturation, image noise, and textureless nature of the target surfaces are avoided. / Jun Cheng. / "June 2006." / Adviser: Ronald Chi-kit Chung. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6499. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 107-117). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

M.A. Epstein. / "March 14, 1958"--Cover. "Reprinted from the 1958 IRE National Convention Record, Part 4"--P. 69. / Bibliography: p. 66. / Army Signal Corps Contract DA36-039-sc-64637. Dept. of the Army Task 3-99-06-108 and Project 3-99-00-100.

Shannon showed that the codes with random-like codeword weight distribution are capable of approaching the channel capacity. However, the random-like property can be achieved only in codes with long-length codewords. On the other hand, the decoding complexity for a random-like codeword increases exponentially with its length. Therefore, code designers are combining shorter and simpler codes in a pseudorandom manner to form longer and more powerful codewords. In this research, a method for designing non-binary compound codes with moderate to high coding rate is proposed. Based on this method, non-binary single parity-check (SPC) codes are considered as component codes and different iterative decoding algorithms for decoding the constructed compound codes are proposed. The soft-input soft-output component decoders, which are employed for the iterative decoding algorithms, are constructed from optimal and sub-optimal a posteriori probability (APP) decoders. However, for non-binary codes, implementing an optimal APP decoder requires a large amount of memory. In order to reduce the memory requirement of the APP decoding algorithm, in the first part of this research, a modified form of the APP decoding algorithm is presented. The amount of memory requirement of this proposed algorithm is significantly less than that of the standard APP decoder. Therefore, the proposed algorithm becomes more practical for decoding non-binary block codes. The compound codes that are proposed in this research are constructed from combination of non-binary SPC codes. Therefore, as part of this research, the construction and decoding of the non-binary SPC codes, when SPC codes are defined over a finite ring of order q, are presented. The concept of finite rings is more general and it thus includes non-binary SPC codes defined over finite fields. Thereafter, based on production of non-binary SPC codes, a class of non-binary compound codes is proposed that is efficient for controlling both random-error and burst-error patterns and can be used for applications where high coding rate schemes are required. Simulation results show that the performance of the proposed codes is good. Furthermore, the performance of the compound code improves over larger rings. The analytical performance bounds and the minimum distance properties of these product codes are studied. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2013.