Character information is hard to detect in billet scene images by CCD camera. In this paper, we present a method for detection of billet characters from measurements of recursive segmented image. This recursive segmen...
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In this paper, a novel image registration method is proposed. In the proposed method, kernel independent component analysis (KICA) is applied to extract features from the image sets, and these features are input vecto...
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In this paper, a novel image registration method is proposed. In the proposed method, kernel independent component analysis (KICA) is applied to extract features from the image sets, and these features are input vectors of feedforward neural networks (FNN). Neural network outputs are those translation, rotation and scaling parameters with respect to reference and observed image sets. Comparative experiments are performed between KICA based method and other six feature extraction based method: principal component analysis (PCA), independent component analysis (ICA), kernel principal component analysis (KPCA), the discrete cosine transform (DCT), Zernike moment and the complete isometric mapping (Isomap). The results show that the proposed method is much improved not only at accuracy but also remarkably at robust to noise.
This paper presents a novel approach to compute DCT-I, DCT-III, and DCT-IV. By using a modular mapping and truncating, DCTs are approximated by linear sums of discrete moments computed fast only through additions. Thi...
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Laser hybrid welding process is widely studied today, with many research groups trying to clarify the phenomena during the process. Many of the changes occurring during laser hybrid welding process can be observed wit...
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Laser hybrid welding process is widely studied today, with many research groups trying to clarify the phenomena during the process. Many of the changes occurring during laser hybrid welding process can be observed with the help of high speed imaging. The high speed of the droplet formation and their movement to the melt pool set strict requirements for the imaging frequency in order to provide reliable information about the process. Because of large number of images produced by the high-speed (over 1000 Hz) imaging, it is time-consuming, error-prone, and frustrating to inspect the process manually, using only the human eyes for the observation. These problems could be alleviated by an automated system for the observation. This paper presents an off-line machine vision system created and used to study videos of CO2 laser-MAG hybrid welding experiments in which welding parameters were changed one at a time. The quality of the welds was observed by visual and macrographic examination. In the study, the regularity of pulse frequency of the arc and direction of filler material droplet flight were measured with the help of machine vision. Due to stable nature of keyhole welding part of the process, these characteristics show the stability of the whole welding process. It was found out that the automatic observation can be used if the quality of the images remains good enough. Experimentally, the inspection system provided information that the welding parameters have an effect on direction of droplet movement. This kind of automatic observation of changes in the process could provide a valuable tool for process optimization. The gathered information can be utilized in achieving an optimized process giving the best possible productivity.
The paper presents an electrically controlled terahertz (THz) band pass filter with liquid crystal (LC). Considering dichroic filters theory, the filter of two-dimensional metallic photonic crystals is designed as a b...
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Recently, a new representation for recognizing instances and categories of scenes called spatial Principal component analysis of Census Transform histograms (PACT) has shown its excellent performance in the scene imag...
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ISBN:
(纸本)9781457720086
Recently, a new representation for recognizing instances and categories of scenes called spatial Principal component analysis of Census Transform histograms (PACT) has shown its excellent performance in the scene image classification task. PACT captures local structures of an image through the Census Transform (CT), meanwhile, large scale structures are captured by the strong correlation between neighboring CT values and the histogram. However, the original spatial PACT only simply concatenates all levels compact histograms together, and discards the difference between various levels. In order to improve this problem, we propose a multi-level kernel machine method, which computes a set of base kernels at each level of pyramid of PACT, and finds optimal weights for best fusing all these base kernels for scene recognition. Experiments on two popular benchmark datasets demonstrate that our proposed multi-level kernel machine method outperforms the spatial PACT on scene recognition. Besides, our method is easy to be implemented comparing with spatial PACT.
In this paper, a novel curve reconstruction method based on A* algorithm from a set of dense scattered points was proposed. Our method can not only reconstruct dense scattered points with single connected complicated ...
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Active deception jamming is one of the common means to jam radar signals. How to effectively recognize active deception jamming is a challenge of modern radar technology. To address the accuracy and real-time of radar...
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In this paper, a pixel-level image fusion algorithm based on Nonsubsampled Contourlet Transform (NSCT) has been proposed. Compared with Contourlet Transform, NSCT is redundant, shift-invariant and more suitable for im...
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ISBN:
(纸本)9780819469519
In this paper, a pixel-level image fusion algorithm based on Nonsubsampled Contourlet Transform (NSCT) has been proposed. Compared with Contourlet Transform, NSCT is redundant, shift-invariant and more suitable for image fusion. Each image from different sensors could be decomposed into a low frequency image and a series of high frequency images of different directions by multi-sacle NSCT. For low and high frequency images, they are fused based on local-contrast enhancement and definition respectively. Finally, fused image is reconstructed from low and high frequency fused images. Experiment demonstrates that NSCT could preserve edge significantly and the fusion rule based on region segmentation performances well in local-contrast enhancement.
A new edge detection operator based on image features is proposed, which analyzes edges in images for edge features in two dimensions. The local extreme of the operator is created at the edge location and a low value ...
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A new edge detection operator based on image features is proposed, which analyzes edges in images for edge features in two dimensions. The local extreme of the operator is created at the edge location and a low value is created at the smooth region. Edges can be located by obtaining the local extreme and a threshold of the operator response. The detection operator is shown to be better than the Canny operator in terms of signal-to-noise ratio and edge location accuracy.
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