Large-scale cloudscapes using noise

Clouds have been of particular interest in computer graphics due to the challenge they present. Clouds are considered fuzzy objects, and need specialized algorithms to model and render realistically. Many techniques exist to model and render clouds that have had much success. This research will take existing techniques in cloud modeling and rendering and create a new technique combining those with noise. The idea is that noise can be used to model large-scale repeatable 3D cloudscapes and to be able to model such cloudscapes much more quickly than current techniques. This would be beneficial to developers of virtual universes that have very many worlds numbering in the ten to hundreds to create convincing cloudscapes on each distinct world

Uniform color space analysis of LACIE image products

The author has identified the following significant results. Analysis and comparison of image products generated by different algorithms show that the scaling and biasing of data channels for control of PFC primaries lead to loss of information (in a probability-of misclassification sense) by two major processes. In order of importance they are: neglecting the input of one channel of data in any one image, and failing to provide sufficient color resolution of the data. The scaling and biasing approach tends to distort distance relationships in data space and provides less than desirable resolution when the data variation is typical of a developed, nonhazy agricultural scene

Cloud Detection And Trace Gas Retrieval From The Next Generation Satellite Remote Sensing Instruments

Thesis (Ph.D.) University of Alaska Fairbanks, 2005The objective of this thesis is to develop a cloud detection algorithm suitable for the National Polar Orbiting Environmental Satellite System (NPOESS) Visible Infrared Imaging Radiometer Suite (VIIRS) and methods for atmospheric trace gas retrieval for future satellite remote sensing instruments. The development of this VIIRS cloud mask required a flowdown process of different sensor models in which a variety of sensor effects were simulated and evaluated. This included cloud simulations and cloud test development to investigate possible sensor effects, and a comprehensive flowdown analysis of the algorithm was conducted. In addition, a technique for total column water vapor retrieval using shadows was developed with the goal of enhancing water vapor retrievals under hazy atmospheric conditions. This is a new technique that relies on radiance differences between clear and shadowed surfaces, combined with ratios between water vapor absorbing and window regions. A novel method for retrieving methane amounts over water bodies, including lakes, rivers, and oceans, under conditions of sun glint has also been developed. The theoretical basis for the water vapor as well as the methane retrieval techniques is derived and simulated using a radiative transfer model

A survey on personal computer applications in industrial design process

Thesis (Master)--Izmir Institute of Technology, Industrial Design, Izmir, 1999Includes bibliographical references (leaves: 157-162)Text in English, Abstract: Turkish and Englishxii, 194 leavesIn this thesis, computer aided design systems are studied from the industrial designer's point of view. The study includes industrial design processes, computer aided design systems and the integration aspects.The technical issues are priorly studied, including current hardware and software technologies. The pure technical concepts are tried to be supported with real-world examples and graphics. Several important design software are examined, whether by personal practice or by literature research, depending on the availability of the software.Finally, the thesis include a case study, a 17" LCD computer monitor designed with a set of graphic programs including two-dimensional and three-dimensional packages.Keywords: Computers, industrial design methods, design software, computer aided design

Automated Detection of Canola/Rapeseed Cultivation from Space: Application of new Algorithms for the Identi cation of Agricultural Plants with Multispectral Satellite Data on the Example of Canola Cultivation

The dispersal of new genes resulting from the cultivation of genetically modified plants holds risks that are difficult to assess. In this context the situation of cultivation is of particular interest since fields are potential sources of the transfer of new genes to non-modified or related plants. The aim of this work is the identification of canola cultivation areas in northern Germany in the studied period from 1995 to 2002. The sizes of the fields and the investigation area pose requirements on the satellite data best met the LANDSAT Thematic Mapper and Enhanced Thematic Mapper and the Indian Remote Sensing Satellite Linear Imaging Scanning Spectrometer/3.The first processing step, the georectification is done by a passpoint correlation which is improved by an additional correction step, based on the correlation of image clips.The next processing step is the identification of clouds and their shadows. Opaque clouds can be identified by their brightness and low top temperature. Thin clouds are identified based on the Haze Optimized Transform method. The third processing step, the classification, is performed by the Mahalanobis Distance Clasifier (MDC) because it only requires training data for one single surface type. The accuracy of the MDC is enhanced by a segmentation of the MDC result used to identify single wrongly identified pixels and to perform region growing to include pixels missed by the MDC.The results are approximated by rectangles of equal orientation and area which allows a simple evaluation of the field distances and other parameters of interest. The results are used to produce statistics to investigate these parameters for the cultivation of canola in northern Germany. The results of the classification are compared to validation data, i.e., edges and positions of known canola fields and agricultural statistics for 1995 and 1999. This validation showed that the total acreage of canola is identified with 70 to 90% accuracy

Computer aided intertrochanteric osteotomy planning and surgery simulation

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1994.Includes bibliographical references (p. 135-144).by Patrick J. Lord.Ph.D

Efficient Many-Light Rendering of Scenes with Participating Media

We present several approaches based on virtual lights that aim at capturing the light transport without compromising quality, and while preserving the elegance and efficiency of many-light rendering. By reformulating the integration scheme, we obtain two numerically efficient techniques; one tailored specifically for interactive, high-quality lighting on surfaces, and one for handling scenes with participating media

Design of Metallic Nanostructures for Wavelength and Angle Selective Light Management.

Sub-wavelength metal nanoparticles demonstrate a resonant coupling to incident optical fields known as the localized surface plasmon resonance, enabling enhanced absorption, scattering, and nano-focusing of light. In this work, plasmonic properties of metal nanoparticles and nanorods are studied and engineered to realize selective management of incident light as a function of wavelength, angle, and polarization, for application to photovoltaics and selectively transmissive / absorptive systems. For photovoltaics (PV) applications, metal nanoparticle scattering is exploited to realize a wavelength selective backscattering layer. Placed behind a thin film PV absorbing layer, an array of silver nanoparticles backscatters light on resonance while off-resonance light is transmitted, allowing engineering of selective transparency vs. absorption and modulation of photocurrent. Further tuning the array by considering anisotropic particle shape (increasing the aspect ratio), the plasmonic resonance becomes a function of both wavelength and incident angle. We propose employing such a nanorod array to realize an angle selective photovoltaic window for building integration: light normal to the window is off resonance, retaining high transmission and window quality visibility, while angled light, including direct sunlight, is resonantly scattered and harvested for conversion to photocurrent. Optical analysis indicates 20 - 30% improvement in direct sunlight absorption and photocurrent is possible without sacrificing window transparency in the viewing direction. Beyond photovoltaics, we consider integrating angle selective metal nanorods with actuating micro-origami structures to control their orientation with respect to incident light. By tuning the plasmonic and angular properties of the system, we propose a novel method to realize balanced 0 - 90+% transmission modulation of the full visible spectrum for application to adjustable smart glass window coatings, potentially significantly improving on current implementations. Large area patterning of deeply sub-wavelength (10's of nm) metal nanorods remains a challenge for traditional nanofabrication techniques. We investigate and describe ways to realize the structures of interest based on the electrochemical synthesis of high aspect ratio self-assembled nanoporous anodized aluminum oxide (AAO) films, including both bottom-up (electroplating) and top-down (reactive ion etching) approaches. Finally, the anisotropic and angle dependent scattering properties of high aspect ratio AAO itself are considered for similar light management applications.PHDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113523/1/brobrts_1.pd