نتایج جستجو برای: wavelet transform and contourlet transform
تعداد نتایج: 16844332 فیلتر نتایج به سال:
Contourlet is a new image representation method, which can efficiently represent contours and textures in images. In this paper, we analyze the distribution of significant contourlet coefficients in different subbands and propose a contourlet image coding algorithm by constructing a virtual low frequency subband and adjusting coding method of SPIHT (Set Partitioning in Hierarchical Trees) algor...
This paper presents an oblivious watermarking scheme based on contourlet transform and quantization index modulus modulation (QIMM).The scheme has the following features. First, the proposed scheme makes better use of multidirectional characteristic of contourlet transform and embed the watermark into the 4 directional high pass sub bands. Second, the scheme avoids the problem of selection of w...
In this work, we study and analyze the contourlet transform for low bit-rate image coding. This image-based geometrical transform has been recently introduced to efficiently represent images with a spars set of coefficients. In order to explore the potentiality of this new transform as a tool for image coding, we developed a direct coding scheme that is based on using non-linear approximation o...
Spatial images are inevitably mixed with different levels of noise and distortion. The contourlet transform can provide multidimensional sparse representations of images in a discrete domain. Because of its filter structure, the contourlet transform is not translation-invariant. In this paper, we use a nonsubsampled pyramid structure and a nonsubsampled directional filter to achieve multidimens...
Considering of the human visual system and the characteristics of remote sensing images, a novel image fusion strategy is presented for panchromatic high resolution image and multispectral image in nonsubsampled contourlet (NSCT) domain. The NSCT can give the asymptotic optimal representation of the edges and contours in image by virtue of the characteristics of good multiresolution, shift-inva...
Evidently, the results of a face recognition system can be influenced by image illumination conditions. Regarding this, the authors proposed a system using wavelet-based contourlet transform normalization as an efficient method to enhance the lighting conditions of a face image. Particularly, this method can sharpen a face image and enhance its contrast simultaneously in the frequency domain to...
Radiometric degradation is a common problem in the image restoration part of many applications. The degradation may involve blurring, information loss due to sampling, quantization effects and various sources of noise. The purpose of image restoration is to estimate the original image from the degraded image. There is much research carried out in an effort to deblur such images. To tackle this ...
This paper presents a novel non-blind watermarking algorithm using contourlet transform. The contourlet transform is preferred for watermarking because of its ability to capture the directional edges and contours superior to other transforms such as cosine transform, wavelet transform, etc. Watermark is encrypted and embedded into high frequency directional subband, which is obtained by perform...
Combined with image processes under microbeam analysis,and based on analyzing the feature of electron probe deeply,the paper presents an optimized method based on Contourlet-lifting wavelet transform and regional variance.firstly,to get the fused image before Contourlet fusion based on regional variance,and then the processing image and the target image will be fused under lifting wavelet trans...
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