This thesis describes the design and instrumentation of an opaque contour-tracing scanner for studies in optical character recognition (OCR). Most previous OCR machines have attempted to recognize characters by mask matching, a technique which requires a large and expensive computer, and which is sensitive to small changes in type font. Contour tracing is a promising new approach to OCR. In contour tracing, the outside of the character is followed, and the resulting horizontal and vertical co-ordinates, X(t) and Y(t), of the scanning spot are processed for recognition. Although much additional research is required on both scanner design and processing algorithms, it is expected that an OCR device which uses a contour-tracing scanner will be significantly less expensive than existing multifont recognition machines. In this thesis, four possible contour-tracing scanners are proposed and evaluated on the basis of cost, complexity and availability of components. The design that was chosen for construction used an X-Y oscilloscope and a photomultiplier as a flying-spot scanner. In instrumenting this design, a digital-to-analogue converter, an up-down counter and many other special purpose logic circuits were designed and constructed. The scanner successfully contour traced Letraset characters, typewritten characters and handprinted characters. At the machines maximum speed, a character is completely traced in approximately 10 msec. Photographs of contour traces and the X(t) and Y(t) waveforms are included in the thesis. Although the present system will only trace two adjacent characters, proposed modifications to the system would enable an entire line of characters to be contour-traced. Included in the thesis are recommendations for further research on scanner design. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

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We have examined the technique of persistent spectral holeburning as a method for analog optical data storage. Two types of materials were examined from a theoretical standpoint, ones which exhibit photochemical holeburning (PHB) and ones which exhibit nonphotochemical holeburning (NPHB). We have presented the conditions under which a PHB material shows a linear relation between hole depth and exposure intensity or exposure time. Also we show that a NPHB material has no such condition. We conclude that a PHB material may be useful for analog optical data storage, while a NPHB material would not. Experiments were conducted with a NPHB material, R' color centers in LiF, to support the NPHB analysis.

QC 351 A7 no. 75 / In the first part of this report the class of two-surface optical systems designated as modules, which have zero third-order spherical aberration relative to a pair of conjugate planes one of which is at infinity, has been further analyzed using the parameters of the Delano y,ÿ diagram. For a given set of three indices of refraction n1, n2, and n3, functional relationships among the y,j7 diagram parameters that eliminate simultaneously other Seidel aberrations are derived. Expressions for zero coma, astigmatism, and Petzval curvature are also given. Criteria for selecting the non - optical parameter k, which defines the desired properties of modules, are described. A one -to-one correspondence between the canonical optical parameters defined in previous studies of modules and certain quantities derivable from the y,ÿ diagram representation is shown. Critical values of the free parameters of modules for both the real and the imaginary cases are derived and defined relative to the y,,y diagram parameters. In the second part of this report an analysis is made of a class of modules referred to as the imaginary -case family depending on the new parameter 0. The critical values 00, 0_, and 0 *, which correspond to those obtained for real-case modules, are defined, and the conditions for their existence in the domain of are derived. These critical values, whose counterparts in the real case exist for both refracting and reflecting systems, do not exist for refracting imaginary-case modules when the indices of refraction are restricted to commonly available optical glasses. The critical values of 0 exist and have fixed values for all reflecting module systems. A method is proposed for classifying imaginary-case modules, which would permit comparison for coupling purposes.

QC 351 A7 no. 77 / Because of their light weight and low cost, transparent plastics would seem to be good materials for optical components. This thesis deals primarily with the feasibility of producing large ( >4 -in. -diam) plastic components of moderate precision (surface accuracies 1 fringe per inch of diameter). The structure and the physical and optical properties of plastics are discussed, with emphasis on their advantages and limitations for optical use. A series of experiments on grinding and polishing of plastics was conducted. Data are presented on grinding rates. Several polishing processes were evaluated, and a polishing technique for plastics was developed. Polishing rate data and surface roughness data are presented for several polishing processes. With proper techniques, we estimate that accuracies of about one fringe per inch are obtainable. A series of experiments was conducted on a process called compression forming, in which heat and pressure are applied to machined preforms in an attempt to obtain precision optical surfaces. The process is described in detail, and experimental results are discussed. Based on experimental results, improved processing conditions are suggested. Further experiments would be required to determine the ultimate process capability.

Photocopy of typescript. / Digitized by Kansas Correctional Industries

A major problem in robotics vision is the segmentation of images of natural scenes in order to understand their content. This thesis presents a new solution to the image segmentation problem that is based on the design of a rule-based expert system. General knowledge about low level properties of an image is formulated into production rules. A number of processes employ the rules to segment the image into uniform regions and connected lines. In addition to the knowledge rules, a set of control rules are also employed. These include meta-rules that embody inferences about the order in which the knowledge rules are matched. They also include focus of attention rules that determine the path of processing within the image. A third set of rules contains the strategy rules which are data-driven inferences about the control rules. They dynamically modify the processing strategy. Different rule ordering and focus of attention strategies are selected according to a set of performance parameters. These measure the quality of the segmentation output at any point in time. Experiments with the knowledge rules resulted in an optimal set based on output quality and processing efficiency. Overall system performance is shown to be qualitatively and quantitatively superior to previous segmentation algorithms.

Future robots are expected to cooperate with humans in daily activities. Efficient cooperation requires new techniques for transferring human skills to robots. This thesis presents an approach on how a robot can extract and replicate a motion by observing how a human instructor conducts it. In this way, the robot can be taught without any explicit instructions and the human instructor does not need any expertise in robot programming. A system has been implemented which consists of two main parts. The first part is data acquisition and motion extraction. Vision is the most important sensor with which a human can interact with the surrounding world. Therefore two cameras are used to capture the image sequences of a moving rigid object. In order to compress the incoming images from the cameras and extract 3D motion information of the rigid object, feature detection and tracking are applied to the images. Corners are chosen as the main features because they are more stable under perspective projection and during motion. A reliable corner detector is implemented and a new corner tracking algorithm is proposed based on smooth motion constraints. With both spatial and temporal constraints, 3D trajectories of a set of points on the object can be obtained and the 3D motion parameters of the object can be reliably calculated by the algorithm proposed in this thesis. Once the 3D motion parameters are available through the vision system, the robot should be programmed to replicate this motion. Since we are interested in smooth motion and the similarity between two motions, the task of the second part of our system is therefore to extract motion characteristics and to transfer these to the robot. It can be proven that the characteristics of a parametric cubic B-spline curve are completely determined by its control points, which can be obtained by the least-squares fitting method, given some data points on the curve. Therefore a parametric cubic B–spline curve is fitted to the motion data and its control points are calculated. Given the robot configuration the obtained control points can be scaled, translated, and rotated so that a motion trajectory can be generated for the robot to replicate the given motion in its own workspace with the required smoothness and similarity, although the absolute motion trajectories of the robot and the instructor can be different. All the above modules have been integrated and results of an experiment with the whole system show that the approach proposed in this thesis can extract motion characteristics and transfer these to a robot. A robot arm has successfully replicated a human arm movement with similar shape characteristics by our approach. In conclusion, such a system collects human skills and intelligence through vision and transfers them to the robot. Therefore, a robot with such a system can interact with its environment and learn by observation.