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The contourlet Transform is an efficient directional multiresolution image representation, but it is not shift-invariant. The nonsubsampled contourlet transform (NSCT), is a fully shift-invariant, multiscale, and multidirection expansion that has a fast implementation, but the computational efficiency is lower than the contourlet transform, such an efficient representation has to be obtained by structured...
In view of conventional contrast enhancement algorithms usually adopt a global approach to enhance all the brightness level of the images which lead to some detailed information being lost and enhancement of the noise in noisy environment, and the remote sensing image contains a lot of low contrast and poor resolution textual information, a fuzzy contrast enhancement algorithm using fuzzy theory in...
In this article, we present a modified robust image watermarking scheme based on the scale-invariant feature transform (SIFT). The watermark is embedded into some local regions extracted from the original image. During embedding, the initial region is divided into some cirque sub-regions with the same area, and each watermark bit is embedded into one sub-region. Besides, it is embedded in the non-subsampled...
How to reduce acquisition time is very important in magnetic resonance imaging (MRI). Compressed sensing MRI emerges recently to suppress the aliasing when undersampling k-space data is employed. However, typical sparse transform for compressed sensing MRI ever used is wavelet, which only captures limited directional information with decay rate M1. In this paper, we introduce contourlet into compressed...
A novel and efficient improving PWF method of speckle reduction in polarimetric SAR image by fusion based on nonsubsampled contourlet transform is proposed. First, the three complex elements (HH, HV, and VV) of the polarimetric scattering matrix were decorrelated to form a new elements matrix. Then we show that the sub-band decompositions of the three elements using nonsubsampled contourlet transform,...
Underwater laser image is seriously contaminated by speckle noise which is due to the coherent nature of the scattering phenomenon. In this paper, the authors propose an adaptive speckle suppression algorithm via the novel nonsubsampled contourlet transform. The statistical model for speckle noise is first analyzed to obtain a simple and tractable solution in a closed analytical form. Gaussian distribution...
As a new image multi-scale geometric analysis tool, the nonsubsampled contourlet transform (NSCT) has many advantages such as multi-scale, localization and multi-direction, and can effectively capture the geometric information of images. Therefore, when the NSCT is introduced to image fusion, the characteristics of original images can be taken better and more information for fusion can be obtained...
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