The power spectrum extended technique applied to images of binary stars in the infrared

Absolute Quadrant Determinations from Speckle Observations of Binary Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100007065 ◽

1992 ◽

Vol 135 ◽

pp. 536-536

Author(s):

W.G. Bagnuolo ◽

B.D. Mason ◽

D.J. Barry ◽

W.I. Hartkopf ◽

H.A. McAlister

Keyword(s):

Power Spectrum ◽

Real Time ◽

Binary Stars ◽

Position Angle ◽

Angle Measurement

AbstractReduction of speckle data obtained for binary stars is typically carried out using power spectrum or, equivalently, autocorrelation methods. An especially powerful algorithm from which accuate differential astronomy can be obtained is the vector autocorrelation technique. While such methods are highly suited to extracting astrometric information from very large volumes of speckle data in near real–time, they inherently introduce a 180° ambiguity in position angle measurement. We briefly summarize results with a new algorithm which maintains most of the simplicity of vector autocorrelation while removing the quadrant ambiguity.

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Fully developed turbulence in accretion discs of binary stars: turbulent viscosity coefficient and power spectrum.

Chaos in Astronomy - Astrophysics and Space Science Proceedings ◽

10.1007/978-3-540-75826-6_42 ◽

2008 ◽

pp. 403-421

Author(s):

A. M. Fridman ◽

D. V. Bisikalo ◽

A. A. Boyarchuk ◽

L. Pustil’nik ◽

Y. M. Torgashin

Keyword(s):

Power Spectrum ◽

Binary Stars ◽

Turbulent Viscosity ◽

Viscosity Coefficient ◽

Accretion Discs ◽

Fully Developed Turbulence ◽

Developed Turbulence

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RSCVn Stars in the Southern Hemisphere

International Astronomical Union Colloquium ◽

10.1017/s0252921100073644 ◽

1979 ◽

Vol 46 ◽

pp. 371-384 ◽

Cited By ~ 3

Author(s):

J.B. Hearnshaw

Keyword(s):

Light Curve ◽

Southern Hemisphere ◽

Orbital Period ◽

Binary Stars ◽

Small Amplitude ◽

Light Variation ◽

Orbital Phase

RSCVn stars are fully detached binary stars which show intrinsic small amplitude (up to 0.3 amplitude peak-to-peak) light variations, as well as, in most of the known cases, eclipses. The spectra are F to G, IV to V for the hotter component and usually KOIV for the cooler. They are also characterised by abnormally strong H and K emission from the cooler star, or, occasionally, from both components. The orbital and light curve periods are in the range 1 day to 2 weeks. An interesting feature is the migration of the light variations to earlier orbital phase, as the light variation period is shorter than the orbital period by a few parts in 10+4to a few parts in 10+3.

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The on-line use of histogram data for high-speed correction and alignment of electron microscope images

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100112713 ◽

1984 ◽

Vol 42 ◽

pp. 556-557

Author(s):

William Krakow

Keyword(s):

Power Spectrum ◽

High Speed ◽

Direct Memory Access ◽

Digital Television ◽

Contrast Transfer Function ◽

The Past ◽

High Resolution Tem ◽

On Line ◽

Correction Of Astigmatism ◽

The Fourier Transform

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.

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Log-log scale roughness spectroscopy of surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146965 ◽

1993 ◽

Vol 51 ◽

pp. 224-225

Author(s):

P. Fraundorf ◽

B. Armbruster

Keyword(s):

Power Spectrum ◽

Autocorrelation Function ◽

Power Spectra ◽

Scanning Force Microscopy ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Force Microscopy ◽

Scanning Force ◽

Lateral Structure ◽

Scale Roughness

Optical interferometry, confocal light microscopy, stereopair scanning electron microscopy, scanning tunneling microscopy, and scanning force microscopy, can produce topographic images of surfaces on size scales reaching from centimeters to Angstroms. Second moment (height variance) statistics of surface topography can be very helpful in quantifying “visually suggested” differences from one surface to the next. The two most common methods for displaying this information are the Fourier power spectrum and its direct space transform, the autocorrelation function or interferogram. Unfortunately, for a surface exhibiting lateral structure over several orders of magnitude in size, both the power spectrum and the autocorrelation function will find most of the information they contain pressed into the plot’s origin. This suggests that we plot power in units of LOG(frequency)≡-LOG(period), but rather than add this logarithmic constraint as another element of abstraction to the analysis of power spectra, we further recommend a shift in paradigm.

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