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Many indoor navigation robots use structured light vision measurement systems (SLVMS) for mapping, localization, and obstacle avoidances. In these systems, the extraction of light stripe skeleton directly affects the accuracy of the final measurements. One of the problems in SLVMS is that when the light is projected to some rough surface it will cause strong diffuse reflection. Thus the light stripe...
A carpet cloak based on graphene is designed and realized by making an approximate hemisphere surface which behaves as a flat surface, and the performances of the cloak are simulated by finite element method. The cloak performs perfectly through tuning conductivity of the graphene. The incident wave can propagate on the curved surface without being disturbed, and an object under the curved surface...
A method aimed at minimizing image noise while optimizing contrast of image subtle features based on nonsubsampled contourlet transform is presented in this paper. Nonsubsampled contourlet transform, which is a shift-invariant version of the contourlet transform, has better performance in representing image edges than separable wavelet for its anisotropy, directionality and shift-invariance, and is...
We propose a new method for image denoising based on contourlet-domain hidden Markov tree (CHMT) models, which have been recently introduced. CHMT models achieve superior denoising results over wavelet-domain HMT (WHMT) models in terms of visual quality. But denoising by means of CHMT still introduces some artifacts due to the lack of translation invariance of the contourlet transform. We employ a...
We propose a new local adaptive shrinkage denoising approach based on the neighborhood characteristics of contourlet coefficients. Classical contourlet shrinkage denoising methods process the contourlet coefficients with a fixed threshold in each subband, without considering the clustering property of the coefficients. The shrinkage denoising method proposed in this paper determines the shrinkage...
We propose contourlet-based algorithms to extract local angle from seismic migrated images and attenuate seismic noise. Steerable pyramid and projection-filter-based complex wavelet transform have been used to extract seismic local angle, while curvelet transform and complex wavelet transform have been used to attenuate seismic noise. However, previously mentioned transforms either have a fixed number...
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