Vision-based positioning systems are founded primarily on a simple image processing technique of identifying various visually significant key-points in an image and relating them to a known coordinate system in a scene. Fiducial markers are used as a means of providing the scene with a number of specific key-points, or features, such that computer vision algorithms can quickly identify them within a captured image. This thesis proposes a reliable vision-based positioning system which utilizes a unique pseudo-random fiducial marker. The marker itself offers 49 distinct feature points to be used in position estimation. Detection of the designed marker occurs after an integrated process of adaptive thresholding, k-means clustering, color classification, and data verification. The ultimate goal behind such a system would be for indoor localization implementation in low cost autonomous mobile platforms.

Vision-based positioning systems are founded primarily on a simple image processing technique of identifying various visually significant key-points in an image and relating them to a known coordinate system in a scene. Fiducial markers are used as a means of providing the scene with a number of specific key-points, or features, such that computer vision algorithms can quickly identify them within a captured image. This thesis proposes a reliable vision-based positioning system which utilizes a unique pseudo-random fiducial marker. The marker itself offers 49 distinct feature points to be used in position estimation. Detection of the designed marker occurs after an integrated process of adaptive thresholding, k-means clustering, color classification, and data verification. The ultimate goal behind such a system would be for indoor localization implementation in low cost autonomous mobile platforms.

Vision-based positioning systems are founded primarily on a simple image processing technique of identifying various visually significant key-points in an image and relating them to a known coordinate system in a scene. Fiducial markers are used as a means of providing the scene with a number of specific key-points, or features, such that computer vision algorithms can quickly identify them within a captured image. This thesis proposes a reliable vision-based positioning system which utilizes a unique pseudo-random fiducial marker. The marker itself offers 49 distinct feature points to be used in position estimation. Detection of the designed marker occurs after an integrated process of adaptive thresholding, k-means clustering, color classification, and data verification. The ultimate goal behind such a system would be for indoor localization implementation in low cost autonomous mobile platforms.

Vision-based positioning systems are founded primarily on a simple image processing technique of identifying various visually significant key-points in an image and relating them to a known coordinate system in a scene. Fiducial markers are used as a means of providing the scene with a number of specific key-points, or features, such that computer vision algorithms can quickly identify them within a captured image. This thesis proposes a reliable vision-based positioning system which utilizes a unique pseudo-random fiducial marker. The marker itself offers 49 distinct feature points to be used in position estimation. Detection of the designed marker occurs after an integrated process of adaptive thresholding, k-means clustering, color classification, and data verification. The ultimate goal behind such a system would be for indoor localization implementation in low cost autonomous mobile platforms.

The use of wireless communication techniques and network centric topologies for portable communication networks and platforms makes it important to investigate new distributed beamforming techniques. Platforms such as micro air vehicles (MAVs), unattended ground sensors (UGSs), and unpiloted aerial vehicles (UAVs) can all benefit from advances in this area by enabling advantages in stealth, enhanced survivability, and maximum maneuverability. Collaborative beamforming is an example of a new technique to utilize these systems which uses a randomly distributed antenna array with a fitting phase coefficient for the elements. In this example, the radiated signal power of each element is coherently added in the far-field region of a specified target direction with net destructive interference occurring in all other regions to suppress sidelobe behavior. A wide variety of topologies can be used to confine geometrically these mobile random arrays for analysis. The distribution function for these topologies must be able to generalize the randomness within the geometry. Gaussian and Uniform distributions are investigated in this analysis, since they provide a way to calculate the statistically averaged beampattern for linear, planar (square and circular), and volumetric (cubical, cylindrical, and spherical) geometries. They are also of practical interest since the impact of array topology on the beampattern can typically be described in closed form. A rigorous analysis is presented first for disc-shaped topologies to motivate the discussion on random array properties and provide several new insights into their behavior. The analyses of volumetric geometries which are of interest to this work are drawn from this planar topology to provide a tractable and coherent discussion on the properties of more complex geometries. This analysis considers Normal and Gaussian distributed array element populations to derive the average beampattern, sidelobe behavior, beamwidth, and directivity. The beampattern is also examined in a similar manor for circular and spherical arrays with a truncated Gaussian distribution. A summary of the random array analysis and its results concludes this thesis.

There are a lot of stand-alone and mobile platforms using transmitters today. Some want to be found while others do not. In our modern society there is a great demand of mobility and communication abilities. This means that several mobile platforms could potentially carry a sensor to record incoming signals to be used in Direction Finding. This thesis identifies the possibility to determine the direction to a transmitter with randomly placed sensors. By conducting a literature review well-known methods such as Time Difference Of Arrival (TDOA) and MUltiple SIgnal Classification (MUSIC) where chosen as methods in this analysis. The methods are applied on two antenna arrays, an Uniform Circular Array (UCA) and a Random Circular Array (RCA). The RCA is generated with randomly placed sensors. The performance in the Direction Of Arrival (DOA) is investigated in presence of time synchronization error and with different numbers of elements, radius and Signal to Noise Ratio (SNR). The ambiguity in the arrays is also investigated to insure a ambiguity-free DOA estimation. The results from this analysis identifies that the accuracy in the DOA estimation is dependent on the number of elements, SNR, the elements positions and the radius of the DF array. Furthermore, the accuracy of a UCA is greater than a RCA when the elements are randomly distributed within the area of a circle with radius R. Finally, it has shown that if time synchronization error occurs between the sensors, then the MUSIC method the accuracy will decrease greatly. / Det finns många individer och mobila platformar som använder sändare idag. Vissa vill bli hittade, andra inte. I vårat moderna samhälle är det en stor efterfrågan på rörlighet och kommunikationsmöjligheter. Detta innebär att många mobila plattformar skulle kunna spela in signaler för att användas i radiopejling. Denna uppsats identifierar möjligheten att bestämma riktningen till en sändare med slumpmässigt placerade sensorer. Genom litteraturstudien identifierades de välkända riktningsmetoder som Time Difference Of Arrivial (TDOA) och MUltiple SIgnal Classification (MUSIC) som vidare valdes som metoder i denna analys. Två antennstrukturer används i analyserna. Den ena är en Uniform Circular Array (UCA) och den andra är en Random Circular Array (RCA). RCA är genererad med slumpmässigt utplacerade sensorer. Prestandan i riktningsuppskattningen undersöks när det existerar ett tidssynkroniseringsfel, olika antal sensorer i antennstrukturerna, varierande radier och olika signaloch brusförhållanden.Ä ventvetydigheter undersöks i strukturerna för att säkerställa att en entydig riktningsbestämning kan utföras. Resultaten implicerar att noggrannheten i riktningsbestämningen är beroende avantalet element, SNR, elementens position och radien i antennmatrisen. Utöver detta visar resultaten att en UCA har högre noggrannhet än en RCA då elementen är slumpmässigt utplacerade inom en cirkelradie, R. Slutligen, om tidssynkroniseringsfel uppstår mellan sensorerna kommer detta resultera i minskad noggrannhet när MUSIC metoden tillämpas.

This thesis describes three readout formats for molecular analyses. A common feature in all works is probing techniques that upon specific target recognition ideally results in equimolar amounts of DNA circles. These are then specifically amplified and detected using any of the techniques presented herein. The first paper presents a method that enables homogeneous digital detection and enumeration of biomolecules, represented as fluorescence-labelled DNA macromolecules. This method offers precise measurements to be performed with a wide linear dynamic range. As an application, two closely related bacterial species were selectively detected. The second paper further investigates and optimizes the properties of the technique presented in paper one. The third paper demonstrates a platform that enables simultaneous quantitative analysis of large numbers of biomolecules. The array format and decoding scheme together propose a digital strategy for decoding of biomolecules. The array and the decoding procedure were characterized and evaluated for gene copy-number measurements. The fourth paper examines a new strategy for non-optical measurements of biomolecules. Characteristics of this technique are investigated, and compared to its optical equivalent, fluorescence polarization.