<p> </p><p>In this thesis a method to compensate camera distortion is developed for an FPGA platform as part of a complete vision system. Several methods and models is presented and described to give a good introduction to the complexity of the problems that is overcome with the developed method. The solution to the core problem is shown to have a good precision on a sub-pixel level.</p><p> </p>

<p>In this thesis, a new way of using predisortion for linearization of power amplifiers is evaluated. In order to achieve an adequate power level for the jamming signal, power amplifiers are used in military jamming systems. Due to the nonlinear characteristic of the power amplifier, distortion will be present at the output. As a consequence, unwanted frequencies are subject to jamming. To decrease the distortion, linearization of the power amplifier is necessary. </p><p>In the system of interest, a portion of the distorted power amplifier output signal is fed back. Using this measurement, a predistortion signal is synthesized to allow suppression of the unwanted frequency components. The predistortion signal is updated a number of times in order to achieve a good outcome. Simulations are carried out in Matlab for testing of the algorithm. </p><p>The evaluation of the new linearization technique shows promising results and that good suppression of distortion components is achieved. Furthermore, new predistortion features are possible to implement, such as predistorsion in selected frequency bands. However, real hardware testing needs to be carried out to confirm the results.</p>

<p>The glazing is today a part of the car design. The customer is more or less taking for granted that his or her view from inside the car is a direct mirror of the outside world. With more complex shapes, lower installation angles and thinner glass it is a great challenge to produce even better quality at a lower price. While the windscreen is regulated by law, the lack of well specified requirements for the optics in the backlight (rear window), together with the absence of direct customer complaints, is causing the optical quality of the backlight to decrease. The requirements and measuring methods used today are described in technical terms and do not correspond to the human perception of optical distortion.</p><p>This report is a first step towards new technical requirements, for the optics of backlights, based on the driver’s perception of optical distortion. The knowledge of how optical transmission distortion occurs, how it should be measured and how it affects the driver, is essential in order to control it.</p><p>Several databases were searched and contacts with experts were established, in order to gain knowledge. The connection between the technical requirements and the human perception of optical distortion in backlights was investigated by using psychophysical methods. A within factorial design was employed with two independent variables; viewing distance from backlight to tailing object and fixation time (viewing time). The result showed a significant difference in perception of optical distortion between 25 and 75 metres. Moreover, optical distortion is, according to the test, more disturbing during free fixation time than for fixation times of about one second.</p><p>The requirements often used for backlights today (12 ± 5 millimetres) allow distortions that 68 percent of the test subjects perceived as disturbing. In order to please the test driver from Volvo the requirements need to be as high as 12 ± 2 millimetres, which correspond to the 96th percentile. Furthermore, the result confirms that dynamic measurements are needed to find a connection to human perception of optical distortion. The principles of a new measuring method that measures the deformation and the dynamic distortion were developed to show the possibilities of measuring what the driver perceives.</p><p>Even if a good measuring method can help controlling the produced glazing it is not enough to optimize the quality of the production. More important is the choice of thickness and curvature of the glass, the installation angle and the manufacturing method. It is important to set about the origin of the problem and develop a good routine of how to work with optical distortions. Optical distortions in backlights, similar to the tested backlight, have a low probability to disturb the driver in such extent that it has an effect on the driving. Nevertheless, it is a source of irritation and discomfort, which do not belong in a premium car.</p> / The video files are also clickable from the pdf file pages 29 and 56.

<p>Spectrally pure signals are an indispensable requirement when the Signal Generator (SG) is to be used as part of a test bed. However, even sophisticated equipment may not comply with the needs imposed by certain applications. This work approaches the problem by using Digital Pre-Distortion (DPD) based on a polynomial memory-less model obtained for the SG.</p><p>Using the SG in arbitrary mode (ARB) an input signal is computer-generated and reproduced by the SG. Measurement accuracy is ensured using coherence sampling and grid matching to the Signal Analyzer (SA). Finally, careful time alignment is used to compare the transmitted and received three-tone signals to obtain the polynomials coefficients.</p><p>Results show that the accuracy of the model and the effectiveness of pre-distortion may vary depending on the amplitude of the three-tone signal. However, using polynomials of 5th and 9th degrees up to 15dB reduction of the 3rd order Inter-Modulation products can be obtained, and spurious powers may be lowered down to 70dBc.</p>

This thesis describes the design of a baseband digital predistortion architecture for radio frequency (RF) amplifier linearization. Existing amplifier linearization techniques are first examined. The nonlinearity of an amplifier can be characterized as amplitude-to-amplitude distortion and amplitude-to-phase distortion. The distortion can be corrected by providing a predistorted driver signal (both in amplitude and phase) to the amplifier. This counteracts the nonlinearity of the amplifier so that the overall system is more linear. A pipelined predistortion architecture is designed to allow fast processing speed, and is capable of providing linearization for a bandwidth of 25 Mhz. The simulation results show significant improvement in amplifier's performance using predistortion technique. The system bandwidth versus cost is examined by using commercially available components. / Graduation date: 1996

This thesis summarizes a study of higher-dimensional distorted objects such as a distorted 5-dimensional Schwarzschild-Tangherlini black hole. It considers a particular type of distortion corresponding to an external, static distribution of matter and fields around this object. The corresponding spacetime can be presented in the generalized Weyl form which has an RxU(1)xU(1) group of isometries. This is a natural generalization of the 4-dimensional Weyl form which was presented in the paper by Emparan and Reall [1]. In the frame of this generalized Weyl form one can derive an exact analytic solution to the Einstein equations which describes the non-linear interaction of the black hole with external matter and gravitational fields. This research focuses on the effects of such interaction on the event horizon and the interior of the black hole. A similar study was presented in the papers [2] for 4-dimensional neutral black holes, where special duality relations between a neutral black hole horizon and singularity were derived. In relation to this work it is interesting to study which properties of distorted black holes remain present in the 5-dimensional case. This thesis also gives an investigation of the d-dimensional Fisher solution which represents a static, spherically symmetric, asymptotically flat spacetime with a massless scalar field. This solution has a naked singularity. It is shown that the d-dimensional Schwarzschild-Tangherlini solution and the Fisher solution are dual to each other. [1] R. Emparan and H. S. Reall, Phys. Rev. D, 65, 084025 (2002). [2] V. P. Frolov and A. A. Shoom, Phys. Rev. D, 76, 064037 (2007).

No description available.

A laser triangulating camera system projects a laser line onto an object to create height curveson the object surface. By moving the object, height curves from different parts of the objectcan be observed and combined to produce a three dimensional representation of the object.The calibration of such a camera system involves transforming received data to get real worldmeasurements instead of pixel based measurements. The calibration method presented in this thesis focuses specifically on small fields ofview. The goal is to provide an easy to use and robust calibration method that can complementalready existing calibration methods. The tool should get as good measurementsin metric units as possible, while still keeping complexity and production costs of the calibrationobject low. The implementation uses only data from the laser plane itself making itusable also in environments where no external light exist. The proposed implementation utilises a complete scan of a three dimensional calibrationobject and returns a calibration for three dimensions. The results of the calibration havebeen evaluated against synthetic and real data.

No description available.

Structural steel design standards recognize lateral torsional buckling as a failure mode governing the capacity of long span unsupported beams with wide flange cross-sections. Standard solutions start with the closed form solution of the Vlasov thin-walled beam theory for the case of a simply supported beam under uniform moments, and modify the solution to accommodate various moment distributions through moment gradient expressions. The Vlasov theory solution is based on the assumption that cross-sectional distortional effects have a negligible effect on the predicted elastic critical moment. The present study systematically examines the validity of the Vlasov assumption related to cross-section distortion through a parametric study. A series of elastic shell finite element eigen-value buckling analyses is conducted on simply supported beams subject to uniform moments, linear moments and mid span point loads as well as cantilevers subject to top flange loading acting at the tip. Cross-sectional dimensions are selected to represent structural steel cross-section geometries used in practice. Particular attention is paid to model end connection details commonly used in practice involving moment connections with two pairs of stiffeners, simply supported ends with a pair of transverse stiffeners, simply supported ends with cleat angle details, and built in fixation at cantilever roots. The critical moments obtained from the FEA are compared to those based on conventional critical moment equations in various Standards and published solutions. The effects of web slenderness, flange slenderness, web height to flange width ratio, and span to height ratios on the critical moment ratio are systematically quantified. For some combinations of section geometries and connection details, it is shown that present solutions derived from the Vlasov theory can overestimate the lateral torsional buckling resistance for beams.