Download or read book Irradiance Statistics Modulation Transfer Function and Phase Structure Function of an Optical Wave in a Turbulent Medium written by Harold T. Yura and published by . This book was released on 1969 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analysis of experimentally observed far-field irradiance statistics, suggesting an approach to calculating the probability distribution for intensity fluctuations of an optical wave in a turbulent medium and expressions for measuring important wave characteristics. Two theoretical treatments of probability distribution are investigated. Because none of the proposed theories can account for irradiance statistics in a consistent manner, it is suggested that a modified geometric optics approach would lead to an improved quantitative understanding of the phenomena. Expressions are derived for measuring wave phase structure function and modulation transfer function. Results are useful in determining the limited resolution obtainable in forming an image through a turbulent medium, as well as in calculating the signal-to-noise ratio of an optical heterodyne detection system. (Author).
Download or read book The Modulation Transfer Function and Phase Structure Function of an Optical Wave in a Turbulent Medium written by R. F. Lutomirski and published by . This book was released on 1969 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Expressions are derived for the dependence of the modulation transfer function (MTF) and the phase structure function (D sub phi) on the Kolmogorov turbulence parameters. In particular, it is demonstrated that certain measurements of the MTF and D sub phi can be interpreted in terms of an outer scale of turbulence being of the order 10-50 cm, values which typically can be expected under inversion conditions. (Author).
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Mean and Variance of the Irradiance for a Phase compensated Optical Link in Turbulence written by Ronald Louis Fante and published by . This book was released on 1975 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last several years considerable progress has been made toward the development of adaptive systems which can compensate for the deleterious effect of atmospheric turbulence on air/air and air/ground optical communications links. One promising method is reciprocity tracking in which a beacon located on the receiver is used in real time to adjust the wavefront of the transmitter. A beacon signal is emitted at x and the phase distribution of this signal is sensed in the plane x = 0. The phase of the transmitter field is then continuously adjusted so that it is the negative of the received beacon phase distribution. because of atmospheric reciprocity, this then continuously compensates for the phase fluctuations induced on the transmitted field by the turbulent medium between the transmitter and receiver.
Download or read book Modulation Transfer Function in Optical and Electro optical Systems written by Glenn D. Boreman and published by SPIE Press. This book was released on 2001 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: This tutorial introduces the theory and applications of MTF, used to specify the image quality achieved by an imaging system. It covers basic linear systems theory and the relationship between impulse response, resolution, MTF, OTF, PTF, and CTF. Practical measurement and testing issues are discussed.
Download or read book Covariance of the Intensity Fluctuations of a Wave in a Random Medium written by Ronald Louis Fante and published by . This book was released on 1974 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Investigation of Atmospheric Turbulence by Stellar Observations written by Jack Lytle Bufton and published by . This book was released on 1971 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study of the optical effects of atmospheric turbulence concentrates on the stellar observation problem. When an infinite plane wave from an incoherent stellar source is sampled by an earth-based telescope, the resultant stellar image exhibits random fluctuations in intensity, position, and size due to turbulence-induced scattering in the intervening atmosphere. One familiar aspect of this problem is the scintillation of starlight apparent to the naked eye. The central aim is to express optical statistics in terms of refractive-index structure constant which pertains to strength of turbulence along the optical path. Data is presented on stellar and meteorological observations made between fall 1968 and spring 1969 with a 0.152-meter diameter refracting telescope. Data was recorded simultaneously on the three parameters of image intensity, motion, and size. The data is interpreted in terms of the theory and used to estimate strength of turbulence. The central result is a series of profiles for refractive-index structure constant along the vertical path. These are constructed using stellar data to calculate parameters of a model.
Download or read book Irradiance Statistics of an Optical Wave in a Turbulent Medium written by R. F. Lutomirski and published by . This book was released on 1969 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The probability distribution for the intensity fluctuations of an optical wave has received considerable attention in the recent literature. Tatarski has claimed the distribution in I in the far field (where geometric optics is not applicable) to be log-normal (i.e., lnI is normal) by applying the central limit theorem to the first order Rytov solution. It has recently been shown that it is necessary to retain the second order Rytov term in order to compute the standard deviation of the intensity fluctuations correct to first order in n1. Hence, Tatarski's derivation of a log-normal distribution function for propagation paths dominated by single scattering cannot be valid. In fact, it can easily be seen that the only first order function (proportional to n1, the index of refraction fluctuations), which gives the correct mean and standard deviation for the intensity, is a linear one. Hence, the correct first order statistics are given only by the first order Born approximation, and application of the central limit theorem then yields a normally distributed intensity distribution. This result should be valid for propagation paths small compared to the single scattering length, Lc, but the experimental evidence supports a log-normal rather than a normal distribution. (Author).
Download or read book Selected Rand Abstracts written by Rand Corporation and published by . This book was released on 1963 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes Reports (R-series), Rand Memorandums (RM-series), papers (P-series), and Books.
Download or read book U S Government Research Development Reports written by and published by . This book was released on 1970 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optics Index written by and published by . This book was released on 1990 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optics Letters written by and published by . This book was released on 2007 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Memorandum written by Rand Corporation and published by . This book was released on 1969 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of the Optical Society of America written by Optical Society of America and published by . This book was released on 1981 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research Memorandum written by and published by . This book was released on 1947 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Optical Apparatus to Determine the Effect of Turbulence on the Modulation Transfer Function of the Atmosphere written by Wayne Thompson Hildebrand and published by . This book was released on 1972 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: An apparatus was designed and constructed to determine the effect of atmospheric turbulence on the modulation transfer function (MTF) of the atmosphere. A reflecting telescope and reticle system provided optical information in the visible region to a silicon photodiode detector which was responsive from .35 micron to 1.1 microns. The output of the detector was processed to measure irradiance modulation from a target of known spatial frequency. The modulation transfer function of the atmospheric transmission medium and the optical system was measured under calm conditions and conditions of turbulence on a 270 meter round trip path through a building corridor. The optical apparatus described was capable of detecting, in the visible range, the degrading effect of turbulence on MTF. All reflective optics were used so that the visual through 10 micrometers range can be covered with use of different detectors. (Author).
Download or read book U S Government Research and Development Reports Index written by and published by . This book was released on 1969 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:
