Determining the sea-roughness spectra from an optical image of the sea surface

Bakhanov, V. V.; Zuikova, E.M.; Kemarskaya, O. N.; Титов, В. И.

doi:10.1007/s11141-006-0036-y

Cited by 4 publications

(3 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…New approach to the wave spectrum estimation is associated with the use of a two-scale wave model [14]. Sea roughness is presented as an ensemble of noninteracting free waves.…”

Section: The Models Of Wave Visibilitymentioning

confidence: 99%

Laboratory Modeling of the Downwelling Coastal Current and the Related Bottom Ekman Layer above the Inclined Bottom in the Rotating Homogeneous and Stratified Fluid

Bakhanov¹,

Demakova²,

Korinenko³

et al. 2018

PhO

Self Cite

View full text Add to dashboard Cite

The method of investigating the sea wave spectra based on spectral processing of the sea surface images made at the diffused sky light is considered. The mechanisms of the sea surface image formation under the oblique viewing are discussed. It is shown that within the framework of a two-dimensional wave model and when the surface is illuminated by a clear sky, the sea surface image spectrum is proportional to that of the wave slopes' spectrum. Described is the developed in the Institute of Applied Physics, RAS optical incoherent light spectrum analyzer permitting to record two-dimensional spectra of the sea surface images in the real time mode. The spectrum analyzer has a wide dynamic range (up to 40-50 dB). The time required to record one two-dimensional spectrum is 1 sec. When the spectrum analyzer is set up at an oceanography platform or a ship bow, the devise can record the wave spectra ranging from 1 meter to several centimeters depending on the height above the sea level and the viewing angle. The method for reconstructing the wave spectrum absolute values using the test object spectrum is represented. Preliminary results of the wave spectra measurements carried out by the optical method (under different wind speeds) from the stationary oceanographic platform in Katsiveli and from a moving vessel are given. The drawn conclusion testifies to conformity of the obtained wave spectra to the available empiric information on the spectra within the wind wave range under consideration. The obtained wave energy angular distributions and the spectra features observed in the slicks are discussed. To study the features of wave spectrum dynamics, developed is the method for imaging the current two-dimensional wave spectra with high resolution of spatial frequency and wave direction. Time dependence of the wave angles' current spectra is represented as the horizontal bands; each of them corresponds to a certain direction of the wave propagation. At that the vertical direction in each band corresponds to the spatial frequency of the wave varying from short to long waves. The brightness of the images is proportional to the slope spectrum in the conventional color scale.

show abstract

“…New approach to the wave spectrum estimation is associated with the use of a two-scale wave model [14]. Sea roughness is presented as an ensemble of noninteracting free waves.…”

Section: The Models Of Wave Visibilitymentioning

confidence: 99%

Laboratory Modeling of the Downwelling Coastal Current and the Related Bottom Ekman Layer above the Inclined Bottom in the Rotating Homogeneous and Stratified Fluid

Bakhanov¹,

Demakova²,

Korinenko³

et al. 2018

PhO

Self Cite

View full text Add to dashboard Cite

show abstract

“…Optical measurement methods can be divided into those which work in the transmission mode [16] (refracted-light recording), stereoscopic [17,18], and the brightness technologies based on the fundamental dependence of the local brightness of the surface parts on their slope angle with respect to the horizon [19][20][21][22][23][24][25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

“…The dataprocessing algorithm involves the space-time filtering of the image, self-checking of the optical-measurement results, and estimation of the error. Such an algorithm seems to allow us to more accurately and completely reconstruct the wave parameters compared with other works on the "classical" photo and video recording of the sea surface [15,26] using in fact the same input data.…”

Section: Introductionmentioning

confidence: 99%

Combined Method for Measuring 3D Wave Spectra. I. Algorithms to Transform the Optical-Brightness Field into the Wave-Height Distribution

Salin

2015

Radiophys Quantum El

View full text Add to dashboard Cite

Although optical tools for measuring the surface-wave characteristics provide the best spatial and temporal resolutions compared with other methods, they face some difficulties while converting the results of indirect measurements into the absolute levels of waves. In this paper, we propose a combined optical method for measuring the 3D spectral density of the heights and the time realizations of the surface-wave profiles. The method involves, first, synchronous recording of the optical-brightness field on a rough-surface area and the surface-oscillation measurement at one or several points and, second, filtering of the spatial image spectrum, so that the filter parameters are also chosen from the condition of maximum correlation of the reconstructed and measured surface oscillations at one or two points. The second part of this work deals with the results of measuring the multi-dimensional wave spectra on the basis of the proposed method.

show abstract