Results 221 to 230 of about 13,144 (256)

Radar speckle: noise or information?

IGARSS '96. 1996 International Geoscience and Remote Sensing Symposium, 2002
The authors examine radar speckle from a non-traditional perspective. Instead of viewing radar speckle as noise, they attempt to assess the information content of radar speckle. A speckle identification algorithm is developed to separate speckle from pixels of "normal" returns. The relationships between land cover types and the density and roughness of
null Zong-Guo Xia, null Yongwei Sheng
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Speckle noise removal by robust modeling

Proceedings 2003 International Conference on Image Processing (Cat. No.03CH37429), 2004
A robust modeling approach is applied to remove speckle noise in synthetic aperture images. Conventional adaptive filtering approaches in speckle filtering smoothes the image selectively depending on the details of underlying textures, and tend to blur details after speckle removal.
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Speckle revisited: analysis of speckle noise in bar-code scanning systems

SPIE Proceedings, 2001
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Marom, E., Krešić-Jurić, Saša, Bergstein, L.   +2 more
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Speckle grain noise in heterodyne techniques for holographic interferometry and speckle photogrammetry

Applied Optics, 1987
Heterodyne techniques greatly improved the accuracy in readout systems for holographic interferometry and dual plate speckle photogrammetry, since the order of interference fringes is read via phase measurements. The limiting accuracy has been traditionally associated with scintillation noise.
J S, Kim, M, Giglio, U, Perini, S, Musazzi   +3 more
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Techniques For Speckle Noise Removal

Optical Engineering, 1981
In this paper, several techniques to reduce speckle noise (more generally signal independent multiplicative noise) in images are studied. The techniques include gray scale modification, frame averaging, low-pass filtering in the intensity and density domains, and application of the short space spectral subtraction image restoration technique in the ...
Jae S. Lim, Hamid Nawab
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Non-Gaussian statistics of speckle noise of Young's fringes in speckle velocimetry

Applied Optics, 1985
In speckle velocimetry, Young's fringes observed during analysis of the multiple-exposure photographs of tracer particles seeding a fluid flow are embedded in a speckle noise that renders their analysis difficult. Some first- and second-order statistical properties of this speckle background are considered in this paper.
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Speckle noise or dust diffraction?

The Physics Teacher, 1999
Abstrcat
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Unsupervised estimation of speckle noise in radar images

International Journal of Imaging Systems and Technology, 1992
AbstractSpeckle in radar images has the characteristic of a multiplicative noise. In this article, two unsupervised methods are introduced to estimate the speckle noise statistics using the mean and the standard deviation of small image blocks (4 × 4, or 6 × 6 pixels).
Jong-Sen Lee, Karl Hoppel, Stephen A. Mango   +2 more
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Escaping path approach for speckle noise reduction

SPIE Proceedings, 2015
A novel fast filtering technique for multiplicative noise removal in ultrasound images was presented in this paper. The proposed algorithm utilizes concept of digital paths created on the image grid presented in [1] adapted to the needs of multiplicative noise reduction.
Marek Szczepanski, Krystian Radlak
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Speckle Noise Reduction by Random Phase Shifters

Japanese Journal of Applied Physics, 1974
Experimental results are given that show that a random phase shifter (RPS) is effective in reducing speckle noise caused by optical defects in coherent imaging systems, including holographic imaging systems. Here the RPS is composed of many tiny transparent blocks, each of which gives a definite phase shift such as O or pi to the transmitting light ...
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