Gareth W. Hughes

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We describe noninvasive techniques to optimize reflectometry measurements, particularly retinal densitometry, which measures the photopigment density difference. With these techniques unwanted scattered light is greatly reduced, and the retina is visualized during measurements. Thus results may be compared for each retinal location, and visible artifacts(More)
The scanning laser ophthalmoscope (SLO) system has been modified to permit direct retinal perimetry. A movable pinhole in a retinal conjugate plane furnishes a mapping stimulus whose retinal locus is directly observable on a video image of the fundus. Scotoma maps in patients with macular disease and physiologic scotomata associated with normal optic discs(More)
An assessment is presented of a Solar Polar Orbiter mission as a Technology Reference Study. The goal is to focus the development of strategically important technologies of potential relevance to future science missions. The technology is solar sailing, and so the use of solar sail propulsion is, thus, defined a priori. The primary mission architecture(More)
Over-learned acoustic stimulus-response pairs were used in a study of human reaction time. The size of the stimulus ensemble was the principal independent variable. Two experienced subjects were used as listeners. The stimuli were natural speech sounds, disc-recorded by a single speaker (M.G.S.), and included the consonant-vowel syllables approximately 30(More)
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