Goal of this paper is the development and evaluation of a fully automatic method for quality assessment of despeckled synthetic aperture radar (SAR) images. The rationale of the new approach is that any structural per...
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ISBN:
(纸本)9780819488060
Goal of this paper is the development and evaluation of a fully automatic method for quality assessment of despeckled synthetic aperture radar (SAR) images. The rationale of the new approach is that any structural perturbation introduced by despeckling, e. g. a local bias of mean or the blur of a sharp edge or the suppression of a point target, may be regarded either as the introduction of a new structure or as the suppression of an existing one. Conversely, plain removal of random noise does not change structures in the image. Structures are identified as clusters in the scatterplot of original to filtered image. Ideal filtering should produce clusters all aligned along the main diagonal. In practice clusters are moved far from the diagonal. Clusters' centers are detected through the mean shift algorithm. A structural change feature is defined at each pixel from the position and population of off-diagonal cluster, according to Shannon's information theoretic concepts. Results on true SAR images (COSMO-SkyMed) will be presented. Bayesian estimators (LMMSE: liner minimum mean squared error: MAP: maximum alpha-posteriori probability) operating in the undecimated wavelet domain have been coupled with segment-based processing. Quality measurements of despeckled SAR images carried out by means of the proposed method highlight the benefits of segmented MAP filtering.
The intensity values in magnetic resonance (MR) images are not standardized. This prevents intensity comparison of different MR volumes that may be needed for visualization, intensity-based processing, and diagnosis. ...
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ISBN:
(纸本)9781424441280
The intensity values in magnetic resonance (MR) images are not standardized. This prevents intensity comparison of different MR volumes that may be needed for visualization, intensity-based processing, and diagnosis. To this effect, this paper introduces a novel, pathology-robust MR intensity normalization algorithm that improves over the literature in three major aspects: 1) Pathology robustness: We achieve this by comparing the input MR volume with a reference volume, identifying the modes of their joint intensity distribution by the mean shift algorithm, and assigning each voxel a confidence value based on the distance of its intensity to the nearby mode. 2) Global and local analysis: We improve both the global similarity of intensities by matching the input and the reference histograms with histogram specification, and the local intensity similarity by minimizing the mean voxel intensity difference with dynamic programming. 3) Structure-preserving fusion of global and local approaches: The optimal fusion of global and local metrics is achieved by preserving the structures (defined as edges) in the normalized data compared with those in the input. We show the effectiveness of the proposed method with both visual and quantitative results.
A method for object tracking combining the accuracy of meanshift with the robustness to occlusion of Kalman filtering is proposed. At first, an estimation of the object's position is obtained by the meanshift tr...
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ISBN:
(纸本)9783642128417
A method for object tracking combining the accuracy of meanshift with the robustness to occlusion of Kalman filtering is proposed. At first, an estimation of the object's position is obtained by the meanshift tracking algorithm and it is treated as the observation for a. Kalman filter. Moreover, we propose a dynamic scheme for the Kalman filter as the elements of its state matrix are updated on-line depending on a measure evaluating the quality of the observation. According to this measure, if the target is not occluded the observation contributes to the update equations of the Kalman filter state matrix. Otherwise, the observation is not taken into consideration. Experimental results show significant improvement with respect to the standard meanshift method both in terms of accuracy and execution time.
mean shift algorithm is recently widely used in tracking clustering, etc, however convergence of mean shift algorithm has not been rigorously proved. In this paper mean shift algorithm with Gaussian profile is studied...
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ISBN:
(纸本)1424400600
mean shift algorithm is recently widely used in tracking clustering, etc, however convergence of mean shift algorithm has not been rigorously proved. In this paper mean shift algorithm with Gaussian profile is studied and applied to tracking of objects. The imprecise proofs about convergence of meanshift are firstly pointed out. Then a convergence theorem and its rigorous convergence proof are provided. Lastly tracking approach of objects based on meanshift is modified. The results of experiment show the modified approach has good performance of object tracking applied to occlusion. The contributions in this paper are expected to further study and application in mean shift algorithm.
Contrast media is a kind of chemical substance used to improve the image quality of Computed Tomography. However, due to its high speed of injection, emergencies (such as capillary hemorrhage) always exist. In view of...
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ISBN:
(纸本)9783642156144
Contrast media is a kind of chemical substance used to improve the image quality of Computed Tomography. However, due to its high speed of injection, emergencies (such as capillary hemorrhage) always exist. In view of this problem, a video object tracking system is implemented to monitor the injection site. The color feature is abstracted from image sequences and used for the meanshift tracking algorithm. The experiment results show that the tracking system is real-time, robust and efficient.
mean shift algorithm has been used in human face tracking during past years and exhibited robust performance compared with other methods. However the existed meanshift methods usually track faces with vertical orient...
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ISBN:
(纸本)9780780397361
mean shift algorithm has been used in human face tracking during past years and exhibited robust performance compared with other methods. However the existed meanshift methods usually track faces with vertical orientation and the tracking effect is deteriorated when the facial orientation changed. In addition, it often adopts the color histogram in RGB color space, which is sensitive to lighting variations. In this paper, we present an adaptive facial orientation template for face tracking in YCb Cr color space and the experimental results show that the tracking is more efficient to adapt the facial orientation and lighting variations than current methods.
mean shift algorithm is recently widely used in tracking clustering, etc, however convergence of mean shift algorithm has not been rigorously proved. In this paper mean shift algorithm with Gaussian profile is studied...
详细信息
mean shift algorithm is recently widely used in tracking clustering, etc, however convergence of mean shift algorithm has not been rigorously proved. In this paper mean shift algorithm with Gaussian profile is studied and applied to tracking of objects. The imprecise proofs about convergence of meanshift are firstly pointed out. Then a convergence theorem and its rigorous convergence proof are *** tracking approach of objects based on meanshift is modified. The results of experiment show the modified approach has good performance of object tracking applied to occlusion. The contributions in this paper are expected to further study and application in mean shift algorithm.
Contrast media is a kind of chemical substance used to improve the image quality of Computed Tomography. However, due to its high speed of injection, emergencies (such as capillary hemorrhage) always exist. In view of...
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Contrast media is a kind of chemical substance used to improve the image quality of Computed Tomography. However, due to its high speed of injection, emergencies (such as capillary hemorrhage) always exist. In view of this problem, a video object tracking system is implemented to monitor the injection site. The color feature is abstracted from image sequences and used for the meanshift tracking algorithm. The experiment results show that the tracking system is real-time, robust and efficient.
although widely used in practice for real time ability, the mean shift algorithm was weak at target model description and was robust for infrared image sequences form motion platform. In order to enhance the adaptabil...
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ISBN:
(纸本)9781424453153;9781424453160
although widely used in practice for real time ability, the mean shift algorithm was weak at target model description and was robust for infrared image sequences form motion platform. In order to enhance the adaptability and target description ability of the mean shift algorithm, meanwhile to make up the shortcomings of the nuclear density estimation based on gradation feature, an adaptive Kalman-mean shift algorithm based on multi-feature fusion was proposed. A target description mode based on gradation-edge feature fusion was applied, while a scale updating item of tracking window was used in the mean shift algorithm based on the relation between mutual information and the object scale. Experimental results demonstrate that the adaptability of mean shift algorithm is enhanced by the improved algorithm, which is effectively applied in the tracking problem for the object of scale variance in long time tracking process.
In this paper, we have proposed a novel approach for segmentation of textured images using combination of Dual Tree Complex Wavelet Transform (DT-CWT) and Dual Tree Rotated complex Wavelet Filters (DT-RCWFs). DT-CWT i...
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ISBN:
(纸本)9781424448586
In this paper, we have proposed a novel approach for segmentation of textured images using combination of Dual Tree Complex Wavelet Transform (DT-CWT) and Dual Tree Rotated complex Wavelet Filters (DT-RCWFs). DT-CWT is used because of its properties such as shift invariance, good directional selectivity, limited redundancy and efficient computation. RCWF sets provide important complementary information to the DT-CWT filter set by extracting texture features in 6 different directions which are 45(0) apart from decomposition directions of DT-CWT. mean shift algorithm is used along with fuzzy c-means (FCM) to make segmentation automatic. The proposed technique is tested on a range of textured images including composite texture images, synthetic texture images as well as real scene images.
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