Richard B. Holmes

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In this paper we describe theoretically the relationship between the finite thickness of a phosphor screen and its spatial-frequency-dependent detective quantum efficiency DQE(f-). The finite thickness of the screen causes a variation in both the total number of light quanta emitted from the screen in a burst from a given x-ray interaction and in the(More)
A method of image recovery using noniterative phase retrieval is proposed and investigated by simulation. This method adapts the Cauchy-Riemann equations to evaluate derivatives of phase based on derivatives of magnitude. The noise sensitivity of the approach is reduced by employing a least-mean-squares fit. This method uses the analytic properties of the(More)
The question of signal-to-noise ratio (SNR) in intensity interferometry has been revisited in recent years, as researchers have realized that various innovations can offer significant improvements in SNR. These innovations include improved signal processing. Two such innovations, the use of positivity and the use of knowledge of the general shape of the(More)
A pupil plane imaging system, consisting of a camera and optics that image the entrance pupil of a telescope, measures scintillation induced by atmospheric turbulence. Algorithms are developed to estimate the distribution of turbulence from scintillation assuming the well known relationship between scintillation scale size and the range of turbulence layer.(More)
The effect of anisotropic Kolmogorov turbulence on the log-amplitude correlation function for plane-wave fields is investigated using analysis, numerical integration, and simulation. A new analytical expression for the log-amplitude correlation function is derived for anisotropic Kolmogorov turbulence. The analytic results, based on the Rytov approximation,(More)
The result of holographic processing is described by using the well-known mode approximation. This approximation yields new expressions for degenerate read-write holography in the optically thick scattering regime in the case in which many transverse modes are occupied. The approach differs from those of previous efforts by the inclusion of the effect of(More)
When light radiating from a distant object passes through extended turbulence, the light is scintillated. Such scintillated light may be received by an optical system and passed to a camera in the focal plane, and used to track an object. Such trackers often use centroid trackers. Then a laser or other light may be projected back toward the object, steered(More)
Quasi-monochromatic light will form laser speckle upon reflection from a rough object. This laser speckle provides information about the shape of the illuminated object. Further information can be obtained if two colors of coherent light are used, provided that the colors are sufficiently close in wavelength that the interference is also measurable. It is(More)
A pupil plane imaging (PPI) system has been designed and implemented to measure scintillation induced by atmospheric turbulence and to estimate key parameters of atmospheric turbulence. A high-speed, high-resolution camera images the pupil of a telescope. The process of estimating normalized intensity variance and the underlying rationale is discussed.(More)