828 research outputs found

    High-dynamic-range displays : contributions to signal processing and backlight control

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    Color Graphics in the Service of Light-Source Visualization and Design

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    In the world of lighting engineering, one of the most active areas of research and industrial application is in the definition of the color rendering properties of light sources. There is a current international standard, and several new methods have been proposed over the last decade. Ordinary consumers are frequently left with little or no knowledge of how to interpret the numerical data produced by any of these systems. This situation has been exacerbated with the advent of LED light sources with widely differing properties. Certain LEDs yield very different results depending on the particular metric in use. We have designed a color graphical system that allows a user to pick a set of (typically) 16 surface color samples, and to be given a realistic comparison of the colors when illuminated by two different light sources, shown on a side-by-side display on a color monitor. This provides a visual analogy to the computations built into the above-mentioned metrics, all of which are based on comparison techniques. This chapter will provide an insight into the design and operation of our lighting computer graphics visualization system. Mention will also be made of similar systems that may be found in the published literature

    Development of a practical and mobile brain-computer communication device for profoundly paralyzed individuals

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    Thesis (Ph.D.)--Boston UniversityBrain-computer interface (BCI) technology has seen tremendous growth over the past several decades, with numerous groundbreaking research studies demonstrating technical viability (Sellers et al., 2010; Silvoni et al., 2011). Despite this progress, BCIs have remained primarily in controlled laboratory settings. This dissertation proffers a blueprint for translating research-grade BCI systems into real-world applications that are noninvasive and fully portable, and that employ intelligent user interfaces for communication. The proposed architecture is designed to be used by severely motor-impaired individuals, such as those with locked-in syndrome, while reducing the effort and cognitive load needed to communicate. Such a system requires the merging of two primary research fields: 1) electroencephalography (EEG)-based BCIs and 2) intelligent user interface design. The EEG-based BCI portion of this dissertation provides a history of the field, details of our software and hardware implementation, and results from an experimental study aimed at verifying the utility of a BCI based on the steady-state visual evoked potential (SSVEP), a robust brain response to visual stimulation at controlled frequencies. The visual stimulation, feature extraction, and classification algorithms for the BCI were specially designed to achieve successful real-time performance on a laptop computer. Also, the BCI was developed in Python, an open-source programming language that combines programming ease with effective handling of hardware and software requirements. The result of this work was The Unlock Project app software for BCI development. Using it, a four-choice SSVEP BCI setup was implemented and tested with five severely motor-impaired and fourteen control participants. The system showed a wide range of usability across participants, with classification rates ranging from 25-95%. The second portion of the dissertation discusses the viability of intelligent user interface design as a method for obtaining a more user-focused vocal output communication aid tailored to motor-impaired individuals. A proposed blueprint of this communication "app" was developed in this dissertation. It would make use of readily available laptop sensors to perform facial recognition, speech-to-text decoding, and geo-location. The ultimate goal is to couple sensor information with natural language processing to construct an intelligent user interface that shapes communication in a practical SSVEP-based BCI

    Advances in Above- and In-Water Radiometry, Volume 3: Hybridspectral Next-Generation Optical Instruments

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    This publication documents the scientific advances associated with new instrument systems and accessories built to improve above- and in-water observations of the apparent optical properties (AOPs) for a diversity of water masses, including optically complex waters. The principal objective is to be prepared for the launch of next-generation ocean color satellites with the most capable commercial off-the-shelf (COTS) instrumentation in the shortest time possible. The technologies described herein are entirely new hybrid sampling capabilities, so as to satisfy the requirements established for next-generation missions. Both above- and in-water instruments are documented with software options for autonomous control of data collection activities as applicable. The instruments were developed for the Hybridspectral Alternative for Remote Profiling of Optical Observations for NASA Satellites (HARPOONS) vicarious calibration project. The state-of-the-art accuracy required for vicarious calibration also led to the development of laboratory instruments to ensure the field observations were within uncertainty requirements. Separate detailed presentations of the individual instruments provide the hardware designs, accompanying software for data acquisition and processing, and examples of the results achieved

    FIRE AND LIFE SAFETY ANALYSIS BONDERSON ENGINEERING PROJETS CENTER

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    A Fire and Life Safety Analysis was performed as one of the requirements for the Master of Science Degree in Fire Protection Engineering from California Polytechnic State University San Luis Obispo. The Fire and Life Safety Analysis consists of a prescriptive analysis as well as a performance based analysis. These analyses were performed on the Bonderson Engineering Projects Center which is part of Cal Poly San Luis Obispo. The prescriptive analysis consisted of the four following parts: Egress Analysis and Design, Fire Detection and Alarm Systems, Water-based Fire Suppression, and Structural Fire Protection. The purpose of the prescriptive analysis was to determine if the Bonderson Engineering Projects Center adhered to the codes and standards applicable to the building. The prescriptive analysis was performed using primarily the 2013 edition of the California Building Code (CBC) along with the 2013 editions of NFPA codes. The egress analysis and design met most of the code requirements. One area that the Bonderson Engineering Projects Center did not meet was door swing direction. Room 104 (See Appendix A for building layout) was originally an office classification, but since construction has been utilized as an assembly space. The decreased occupant load factor resulted in a new occupant load which is greater than 50 persons. Per CBC 1008.1.2 exit doors must swing in the direction of egress travel where serving a room or area containing an occupant load of 50 or more persons, which the building does not adhere to. The fire detection and alarm systems analysis was performed primarily utilizing NFPA 72. The building had multiple shortcomings in regards to spacing gaps of the detection devices. These shortcomings were found on the first and second floor, including the lobby, robotics room, project integration room and computer cluster room. The water-based fire suppression system analysis was performed primarily utilizing NFPA 13 and NFPA 25. The water supply and sprinkler system are acceptable. The structural fire protection analysis was performed primarily utilizing the CBC. The main shortcoming discovered was in relation to the atrium. The building must have a 1 hour fire barrier separating atrium spaces from adjacent spaces or it must provide an acceptable smoke control system. The building provides neither of these provisions. The performance based analysis was performed in order to ascertain the ability for the occupant of a building to evacuate safely in the event of a fire. Two separate fire scenarios were evaluated using Fire Dynamics Simulator (FDS) and Pathfinder. Tenability criteria was determined and used in conjunction with FDS in order to determine the available safe egress time (ASET). This was compared against the required safe egress time (RSET) which was determined using Pathfinder. The RSET time was greater than the ASET time, meaning occupants would not be able to safely evacuate the building in the event of an emergency

    Individual Colorimetric Observers for Personalized Color Imaging

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    Colors are typically described by three values such as RGB, XYZ, and HSV. This is rooted to the fact that humans possess three types of photoreceptors under photopic conditions, and human color vision can be characterized by a set of three color matching functions (CMFs). CMFs integrate spectra to produce three colorimetric values that are related to visual responses. In reality, large variations in CMFs exist among color-normal populations. Thus, a pair of two spectrally different stimuli might be a match for one person but a mismatch for another person, also known as observer metamerism. Observer metamerism is a serious issue in color-critical applications such as soft proofing in graphic arts and color grading in digital cinema, where colors are compared on different displays. Due to observer metamerism, calibrated displays might not appear correctly, and one person might disagree with color adjustments made by another person. The recent advent of wide color gamut display technologies (e.g., LEDs, OLEDs, lasers, and Quantum Dots) has made observer metamerism even more serious due to their spectrally narrow primaries. The variations among normal color vision and observer metamerism have been overlooked for many years. The current typical color imaging workflow uses a single standard observer assuming all the color-normal people possess the same CMFs. This dissertation provides a possible solution for observer metamerism in color-critical applications by personalized color imaging introducing individual colorimetric observers. In this dissertation, at first, color matching data were collected to derive and validate CMFs for individual colorimetric observers. The data from 151 color-normal observers were obtained at four different locations. Second, two types of individual colorimetric observer functions were derived and validated. One is an individual colorimetric observer model, an extension of the CIE 2006 physiological observer incorporating eight physiological parameters to model individuals in addition to age and field size inputs. The other is a set of categorical observer functions providing a more convenient approach towards the personalized color imaging. Third, two workflows were proposed to characterize human color vision: one using a nomaloscope and the other using proposed spectral pseudoisochromatic images. Finally, the personalized color imaging was evaluated in a color image matching study on an LCD monitor and a laser projector and in a perceived color difference study on a SHARP Quattron display. The personalized color imaging was implemented using a newly introduced ICC profile, iccMAX

    Pilot factors guidelines for the operational inspection of navigation systems

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    A computerized human engineered inspection technique is developed for use by FAA inspectors in evaluating the pilot factors aspects of aircraft navigation systems. The short title for this project is Nav Handbook. A menu-driven checklist, computer program and data base (Human Factors Design Criteria) were developed and merged to form a self-contained, portable, human factors inspection checklist tool for use in a laboratory or field setting. The automated checklist is tailored for general aviation navigation systems and can be expanded for use with other aircraft systems, transports or military aircraft. The Nav Handbook inspection concept was demonstrated using a lap-top computer and an Omega/VLF CDU. The program generates standardized inspection reports. Automated checklists for LORAN/C and R NAV were also developed. A Nav Handbook User's Guide is included

    Development of a Star Tracker-Based Reference System for Accurate Attitude Determination of a Simulated Spacecraft

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    The goal of this research effort is to investigate the analysis, design, integration, testing, and validation of a complete star tracker and star field simulator system concept for AFIT\u27s satellite simulator, SimSat. Previous research has shown that while laboratory-based satellite simulators benefit from star trackers, the approach of designing the star field can contribute significant error if the star field is generated on a flat surface. To facilitate a star pattern that better represents a celestial sky, a partially hemispherical dome surface is suspended above SimSat and populated with a system of light emitting diodes of various intensities and angles of separation. Test results show that the spherical star pattern surface is effective in minimizing the effects of parallax when imaging in a finite conjugate mode and that more reliable attitude information within 1 degree of accuracy can be attained. The added capability to research star pattern recognition and attitude determination algorithms in the future is also significant

    A novel RGBW pixel for LED displays

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    In this work, a novel pixel configuration RGBW, consisting of red (R), green (G), blue (B), and white (W) LEDs, is employed and investigated for color generation. Energy consumption and various hues of new pixels are compared to standard pixels consisting of RGB LEDs. Human perception experiments are conducted in order to study the perceptual difference between the two architectures when the same colors are generated using RGBW vs. RGB. Power measurements for an 8x8 pixel LED display has demonstrated up to 49% power savings for gray scale, over 30% power savings for low saturated colors, and up to 12% for high saturated colors using RGBW as an alternative. Furthermore, human perception studies has shown that vast majority of test subjects could not distinguish between most colors displayed using RGB and RGBW showing that RGBW is an excellent substitute for RGB. Statistics has shown that 44% of test subjects found the colors in gray scale to be the same, whereas 82% and 95% of test subject found low saturated colors and high saturated colors, respectively, to be identical
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