Conventional image sensors achieve color imaging using absorptive organic dye filters. These face considerable challenges however in the trend toward ever higher pixel densities and advanced imaging methods such as multispectral imaging and polarization-resolved imaging. In this dissertation, we investigate the optical properties of vertical silicon nanowires with the goal of image sensor applications. First, we demonstrate a multispectral imaging system that uses a novel filter that consists of vertical silicon nanowires embedded in a transparent medium. Second, we demonstrate pixels consisting of vertical silicon nanowires with integrated photodetectors. We show that their spectral sensitivities are governed by nanowire radius, and perform color imaging. In addition, we demonstrate polarization-resolving photodetectors consisting of silicon nanowires with elliptical cross sections. Finally, we discuss a dual detector device. Each pixel consists of vertical silicon nanowires (incorporating photodetectors) formed above a silicon substrate (that also incorporates a photodetector). Our method is very practical from a manufacturing standpoint because all filter functions are defined at the same time through a single lithography step. In addition, our approach is conceptually different from current filter-based methods, as absorbed light in our device is converted to photocurrent, rather than discarded. This ultimately presents the opportunity for very high photon efficiency. / Engineering and Applied Sciences

This work investigates the optimal measurement matrices that can be used in compressive sensing (CS) image sensors. It also optimizes CMOS current-model pixel cell circuits for CS image sensors. Based on the outcomes from these optimization studies, three CS image senor circuits with compression ratios of 4, 6, and 8 are designed with using a 130 nm CMOS technology. The pixel arrays used in the image sensors has a size of 256X256. Circuit simulations with benchmark image Lenna show that the three images sensors can achieve peak signal to noise ratio (PSNR) values of 37.64, 33.29, and 32.44 dB respectively.

To manufacture better cameras at lower costs is of great interest to the surveillance industry. Inthe process of manufacturing cameras, the mounting of the optics and the digital image sensor, isa crucial part of producing a high quality image. For high resolution cameras, mechanical passivealignment of the optics and image sensor is insufficient for producing a picture of adequate quality.This is caused by inherit problems from manufacturing, resulting in performance issues for theparts. For the lens, these performance issues causes the light path to deviate and the focal pointto be off center. In the same way, manufacturing of the image sensor causes similar problems.These problems results in an image of subpar quality, if the interface solely relies on mechanicalpassive alignment. To compensate for these problems a computer aided machine is used to alignthe lens and the image sensor. The lens and the sensor, are placed in the machine, aligned forbest possible image quality and fixated in its place. This fixation is done with UV light curedadhesive. The process is drawn with some issues, the curing of the adhesive causes unpredictableshrinkage that affects the image quality. In addition, contaminations such as dust or dirt on theparts, are impossible to remove once the fixation is complete, causing blemishes on the images.These faults results in scrapping of expensive parts, which is costly for the manufacturer. Thisthesis aims to find alternative mounting solutions to the parts, that result in less scrapping ofexpensive components, without sacrificing image quality. The result is two concepts that can beused as inspiration for future improvement of surveillance camera manufacturing. A new adhesiveinterface, that can reduce, manufacturing cost and the unreliable shrinkage of the adhesive, as wellas a new mechanical coupling that allows reassembly after cleaning, is presented.iii

Diese Arbeit befasst sich mit dem Entwurf eines asynchron arbeitenden, zeitbasierten CMOS–Bildsensors mit erhöhtem Dynamikbereich und Unterdrückung zeitlich redundanter Daten. Aufgrund immer kleinerer Strukturgrößen in modernen Prozessen zur Fertigung von Halbleitern und einer gleichzeitig physikalisch bedingt immer geringeren Skalierbarkeit konventioneller Bildsensoren wird es zunehmend möglich und praktikabel, Signalverarbeitungsansätze auf Pixelebene zu implementieren. Unter Berücksichtigung dieser Entwicklungen befasst sich die folgende Arbeit mit dem Entwurf eines neuartigen CMOS–Bildsensors mit nahezu vollständiger Unterdrückung zeitlich redundanter Daten auf Pixelebene. Jedes photosensitive Element in der Matrix arbeitet dabei vollkommen autonom. Es detektiert selbständig Änderungen in der Bestrahlung und gibt den Absolutwert nur beim Auftreten einer solchen Änderung mittels asynchroner Signalisierung nach außen. Darüber hinaus zeichnet sich der entwickelte Bildaufnehmer durch einen, gegenüber herkömmlichen Bildsensoren, deutlich erhöhten Dynamikbereich und eine niedrige Energieaufnahme aus, wodurch das Prinzip besonders für die Verwendung in Systemen für den mobilen Einsatz oder zur Durchführung von Überwachungsaufgaben geeignet ist. Die Realisierbarkeit des Konzepts wurde durch die erfolgreiche Implementierung eines entsprechenden Bildaufnehmers in einem Standard–CMOS–Prozess nachgewiesen. Durch die Größe des Designs von 304 x 240 Bildelementen, die den Umfang üblicher Prototypen-Realisierungen deutlich übersteigt, konnte speziell die Anwendbarkeit im Bereich größerer Sensorfelder gezeigt werden. Der Schaltkreis wurde erfolgreich getestet, wobei sowohl das Gesamtsystem als auch einzelne Schaltungsteile messtechnisch analysiert worden sind. Die nachgewiesene Bildqualität deckt sich dabei in guter Näherung mit den theoretischen Vorbetrachtungen.

Diese Arbeit befasst sich mit dem Entwurf eines asynchron arbeitenden, zeitbasierten CMOS–Bildsensors mit erhöhtem Dynamikbereich und Unterdrückung zeitlich redundanter Daten. Aufgrund immer kleinerer Strukturgrößen in modernen Prozessen zur Fertigung von Halbleitern und einer gleichzeitig physikalisch bedingt immer geringeren Skalierbarkeit konventioneller Bildsensoren wird es zunehmend möglich und praktikabel, Signalverarbeitungsansätze auf Pixelebene zu implementieren. Unter Berücksichtigung dieser Entwicklungen befasst sich die folgende Arbeit mit dem Entwurf eines neuartigen CMOS–Bildsensors mit nahezu vollständiger Unterdrückung zeitlich redundanter Daten auf Pixelebene. Jedes photosensitive Element in der Matrix arbeitet dabei vollkommen autonom. Es detektiert selbständig Änderungen in der Bestrahlung und gibt den Absolutwert nur beim Auftreten einer solchen Änderung mittels asynchroner Signalisierung nach außen. Darüber hinaus zeichnet sich der entwickelte Bildaufnehmer durch einen, gegenüber herkömmlichen Bildsensoren, deutlich erhöhten Dynamikbereich und eine niedrige Energieaufnahme aus, wodurch das Prinzip besonders für die Verwendung in Systemen für den mobilen Einsatz oder zur Durchführung von Überwachungsaufgaben geeignet ist. Die Realisierbarkeit des Konzepts wurde durch die erfolgreiche Implementierung eines entsprechenden Bildaufnehmers in einem Standard–CMOS–Prozess nachgewiesen. Durch die Größe des Designs von 304 x 240 Bildelementen, die den Umfang üblicher Prototypen-Realisierungen deutlich übersteigt, konnte speziell die Anwendbarkeit im Bereich größerer Sensorfelder gezeigt werden. Der Schaltkreis wurde erfolgreich getestet, wobei sowohl das Gesamtsystem als auch einzelne Schaltungsteile messtechnisch analysiert worden sind. Die nachgewiesene Bildqualität deckt sich dabei in guter Näherung mit den theoretischen Vorbetrachtungen.

The theoretical and experimental investigation of the novel in-line CMOS image sensor was performed. This sensor is aimed to investigate particle size distribution, particle concentration and shape in hydraulic liquid in order to implement the proactive maintenance of hydraulic equipment. The existing instruments such as automatic particle counters and techniques are not sufficiently enough to address this task because of their restricted sensitivity, limit of concentration to be measured and they cannot determine particle shape. Other instruments cannot be used as inline sensors because they are not resistant to the arduous conditions such as high pressure and vibration. The novel mathematical model was proposed as it is not possible to use previously developed techniques based on using optical system and complicated algorithms. This model gives the output signal of the image sensor depending on the particle size, its distance from the light source (LED) and image sensor. Additionally, the model takes into account the limited exposure time and particle track simulation. The results of simulation based on the model are also performed in thesis. On the basis of the mathematical model the image processing algorithms were suggested in order to determine particle size even when this size is lower than pixel size. There are different approaches depending on the relation between the size of the particle and the pixel size. The approach to the volume of liquid sample estimation was suggested in order to address the problem of low accuracy of concentration measurement by the conventional automatic particle counters based on the single photodiode. Proposed technique makes corrections on the basis of particle velocity estimation. Approach to the accuracy estimation of the sensor was proposed and simulation results are shown. Generally, the accuracy of particle size and concentration measurement was considered. Ultimately, the experimental setup was used in order to test suggested techniques. The mathematical model was tested and the results showed sufficient correlation with the experiment. The zinc dust was used as a reference object as there are the particles within the range from 1 to 25 microns which is appropriate to check the sensitivity. The results of experiments using reference instrument showed the improved sensitivity and accuracy of volume measured compared to the reference one.

Structured Light Imaging (SLI) is a means of digital reconstruction, or Three-Dimensional (3D) scanning, and has uses that span many disciplines. A projector, camera and Personal Computer (PC) are required to perform such 3D scans. Slight variances in synchronization between these three devices can cause malfunctions in the process due to the limitations of PC graphics processors as real-time systems. Previous work used a Field Programmable Gate Array (FPGA) to both drive the projector and trigger the camera, eliminating these timing issues, but still needing an external camera. This thesis proposes the incorporation of the camera with the FPGA SLI controller by means of a custom printed circuit board (PCB) design. Featuring a high speed image sensor as well as High Definition Multimedia Interface (HDMI) input and output, this PCB enables the FPGA to perform SLI scans as well as pass through HDMI video to the projector for Spatial Augmented Reality (SAR) purposes. Minimizing ripple noise on the power supply by means of effective circuit design and PCB layout, realizes a compact and cost effective machine vision sensing solution.

The rise of organometal halide perovskite materials with extremely intriguing properties have opened a new horizon in the design of high speed and low price optoelectronic devices. The bandgap in the crystalline structure of these materials can be easily tuned for various applications and their dominant non-excitonic dynamics eliminate the requirement of a bulk or heterostructure for charge carrier separation. These unique properties increase the photo-sensitivity of perovskite-based optoelectronics and provide them with a low time constant, resulting in high precision fast devices. Realization of perovskite-based devices translates directly to inexpensive and simplified architectures of optoelectronic systems. In perovskite-based devices, costly silicon or wide bandgap semiconductor fabrication technology is largely replaced by solution processable methods. Their bandgap tunability allows the reduction of the required optical accessories and interconnects in optoelectronic components. For instance, a tuned perovskite-based detector can substitute a narrowband detecting system consisting of a conventional detector and its required optical accessories such as lenses and color filters. These properties of perovskite-based devices lead to the realization of inexpensive, low power and high-performance optoelectronic systems. In this work, the design of a narrowband, low noise, high performance and stable photodetector based on organic-inorganic hybrid perovskite structure is proposed. The full width at half maximum (FWHM) of the device would be in the nanometer range. The response of the device can be tuned using either different ratios of the lead salts or synthetic dyes (macromolecules) in the crystalline structure for color discrimination in machine vision and imaging applications. Non-excitonic photocarrier generation, tunability of the optical bandgap and low voltage requirements for charge carrier generation are the keys to the utility of this optoelectronic device. The goals of this project were to identify the required functional materials (lead salts and synthetic dyes based on their molecular structures) and optimize their performance; the study of their effect on the charge collection narrowing mechanism and bandwidth specifications defined for detectivity, linear dynamic range (LDR) and photoresponse speed. To achieve these goals, it was proposed to study the light detection properties as well as spectroscopic and semiconductor parameter characteristics of fabricated devices. The design considerations of such devices are versatile and may be modulated for different applications.

<p>Devices have become increasingly more interconnected to their surroundings over the last few years. The introduction of Bluetooth is likely to further accelerate this trend. With Bluetooth's bandwidth and expected low price, many devices will likely be fitted with Bluetooth chips and thus enable more devices to exchange data. </p><p>This master thesis aims at connecting a Personal Digital Assistant to an ARM Thumb microcontroller over Bluetooth. To the ARM Thumb shall an image capturing device be interfaced and the captured images shall be sent over Bluetooth to the Personal Digital Assistant which shall display them.</p>

Devices have become increasingly more interconnected to their surroundings over the last few years. The introduction of Bluetooth is likely to further accelerate this trend. With Bluetooth's bandwidth and expected low price, many devices will likely be fitted with Bluetooth chips and thus enable more devices to exchange data. This master thesis aims at connecting a Personal Digital Assistant to an ARM Thumb microcontroller over Bluetooth. To the ARM Thumb shall an image capturing device be interfaced and the captured images shall be sent over Bluetooth to the Personal Digital Assistant which shall display them.