Automatic Detection of Dust and Scratches in Silver Halide Film using Polarized Dark-Field Illumination

We present a method to automatically detect dust and scratches on photographic material, in particular silver halide film, where traditional methods for detecting and removing defects fail. The film is digitized using a novel setup involving crosspolarization and dark-field illumination in a cardinal light configuration, which compresses the signal and highlights the parts that are due to defects in the film. Applying a principal component analysis (PCA) on the four cardinal images allows us to further separate the signal part of the film from the defects. Information from all four principal components is combined to produce a surface defect mask, which can be used as input to inpainting methods to remove the defects. Our method is able to detect most of the dust and scratches while keeping false-detections low

Holographic instrumentation applications

Investigating possibilities and limitations of applying holographic techniques to aerospace technolog

Photography equipment and techniques. A survey of NASA developments

The Apollo program has been the most complex exploration ever attempted by man, requiring extensive research, development, and engineering in most of the sciences before the leap through space could begin. Photography has been used at each step of the way to document the efforts and activities, isolate mistakes, reveal new phenomena, and to record much that cannot be seen by the human eye. At the same time, the capabilities of photography were extended because of the need of meeting space requirements. The results of this work have been applied to community planning and ecology, for example, as well as to space and engineering. Special uses of standard equipment, modifications and new designs, as well as film combinations that indicate actual or potential ecological problems are described

Holography: A survey

The development of holography and the state of the art in recording and displaying information, microscopy, motion, pictures, and television applications are discussed. In addition to optical holography, information is presented on microwave, acoustic, ultrasonic, and seismic holography. Other subjects include data processing, data storage, pattern recognition, and computer-generated holography. Diagrams of holographic installations are provided. Photographs of typical holographic applications are used to support the theoretical aspects

Assessment of plastics in the National Trust: a case study at Mr Straw's House

The National Trust is a charity that cares for over 300 publically accessible historic buildings and their contents across England, Wales and Northern Ireland. There have been few previous studies on preservation of plastics within National Trust collections, which form a significant part of the more modern collections of objects. This paper describes the design of an assessment system which was successfully trialled at Mr Straws House, a National Trust property in Worksop, UK. This system can now be used for future plastic surveys at other National Trust properties. In addition, the survey gave valuable information about the state of the collection, demonstrating that the plastics that are deteriorating are those that are known to be vulnerable, namely cellulose nitrate/acetate, PVC and rubber. Verifying this knowledge of the most vulnerable plastics enables us to recommend to properties across National Trust that these types should be seen as a priority for correct storage and in-depth recording

An appraisal and developments of laser holography for interferometric engineering measurement

Holography is a two-stage method of imagery in which both amplitude and phase information characterizing a wavefront are recorded, and subsequently reconstructed. Only with the advent of laser light sources in the early 1960s did the method become practical, motivating research into applications. One of these, holographic interferometry, was based on the fact that a reconstructed wavefront from a hologram could be used as a reference for interferometric comparison. This enabled interferometry to be extended to objects having scattering surfaces of any shape, and the potential of the method in engineering measurement was considered to be high. A literature survey carried out at the start of this project (1967 to 1968), and reported in Chapter 2, revealed that many potential applications in the fields of stress analysis, vibration analysis, fault detection in materials and structures, and dimensional inspection, had been proposed but were not quickly materializing. This was seen to be partly due to practical difficulties necessitating laboratory procedures, and partly due to difficulties in analysing interferograms to obtain specific measurements. Accordingly, the aims of this project were: (i) to develop apparatus and methods that would simplify and improve the practice of holographic interferometry and the interpretation of results; (ii) to investigate fringe interpretation, and to assess the accuracy and general feasibility, in relation to practical measurements of surface deformation. [Continues.

Small business innovation research. Abstracts of completed 1987 phase 1 projects

Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered

Investigations on hybrid organic-inorganic perovskites for high performance solar cells

Undoubtedly, perovskite solar cells have become a key player in 3rd generation photovoltaics over the last few years. Although it is only in 2012 that the first solid state perovskite solar cell was reported, power conversion efficiencies have increased so rapidly that PSCs are now serious contenders to the well-established and marketed thin-film and wafer technologies. Over the timespan on this work, over 3000 published articles in peer-review journals have been published. The work that I report in this thesis is merely a small contribution to the gigantic amount of data, models and theories that have been made over the last 4 years. I hope that my modest contribution will be of value to the scientific community. Over the course of this work, I attempted not to focus my attention on a single issue that relates to perovskite photovoltaics, but to approach it from different perspectives. As a result, a wide array of subjects have been treated. Starting with the fabrication of perovskite solar cells, an innovative way to deposit thin film of perovskite from solution is reported, using a two-step deposition technique. Using this approach, the power conversion efficiency of perovskite solar cells has been increased from 12.3% to over 17% in less than a year. Subsequently, I looked into the possible compositional variations of the perovskite layer. This study showed that the cation methylammonium and formamidinium can be used inter- changeably using the deposition technique that we have reported on earlier. We showed that a mixture of the two cations leads to a stabilization of the tetragonal perovskite phase and shrinks the optical band gap of the photoabsorber, allowing more photons to be absorbed and converted into electrons. Following this work, I studied some of the reactivity properties of the phase pure organic inorganic CH3NH3PbX3(X=Cl,Br,I). Notably, it could be shown that the halide component can be easily exchanged by another one from a simple solution based anion exchange reaction. Later, the power conversion characteristics of perovskite solar cells were investigated. By developing a electronic circuit allowing versatile power point tracking of the solar cells, a new algorithm that deals with the issues specifically related to perovskite solar cells is reported. i A major topic of my work was the study of the frequency resolved dynamics that results for the generation carriers by light. Using a novel way to measure the intensity modulated spectral response of perovskite solar cells, I was able to identify some of the key limiting factors that cap the power conversion efficiency of the devices. A numerical model that answers to the laws of carrier dynamics was assembled and used as a tool to better understand perovskite solar cells. Finally, I reported on a way to deal with the end of life of perovskite solar cells. Some of the relevant regulatory framework in the European Union that deals with the recycling of solar panels are highlighted. Using the concept of "upcycling", a way to recycle the valuable components of the solar cell in an efficient way was outlined