imageprocessing is usually associated withpatternrecognition and is rather treated as a subject outside of the computer graphics interest. Basically computer graphics algorithms are used for the visualization of sc...
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imageprocessing is usually associated withpatternrecognition and is rather treated as a subject outside of the computer graphics interest. Basically computer graphics algorithms are used for the visualization of scenes or models described using some abstract notation, while imageprocessing is used on the opposite way -i.e. when finding an abstract description of an analyzed pattern. this paper proposes to use the imageprocessing approach for rendering optical effects in computer graphics algorithms. Proposed algorithms can be used for the generation of realistic and artistic optical effects in real-time, in, for example, visual simulators, virtual reality or multi-media applications. (C) 1997 Elsevier Science B.V.
It is a key technology to detect the edge of the droplet profile exactly for application in drop volume calculation, liquid target identification and liquid characteristics analysis. the droplet images in various stag...
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ISBN:
(纸本)9780819469502
It is a key technology to detect the edge of the droplet profile exactly for application in drop volume calculation, liquid target identification and liquid characteristics analysis. the droplet images in various stages during the drop growth are firstly acquired and stored real-timely through ICCD. After a series of preprocessing, including image cutting, noise filtering, image segmentation and filling, a proper edge detection method is chosen to extract the droplet image profile. the principle and algorithm of some classical and newly developed methods for edge detection are introduced and compared in detail, such as differential operator, Laplacian operator, improved Canny operator, wavelet transformation, mathematical morphology, fuzzy operator and fractal geometry. Wavelet transformation can be used effectively for extracting the droplet image profile, because of its advantages of multiple resolution, focus variation and edge enhancement. the image records of the droplet formation and the detected profile curves are presented.
A novel visualization method of terahertz time-domain spectroscopy (thz-TDS) image is presented, which is based on principal component analysis (PCA) technique. the proposed method include three processing steps: firs...
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ISBN:
(纸本)9780819469519
A novel visualization method of terahertz time-domain spectroscopy (thz-TDS) image is presented, which is based on principal component analysis (PCA) technique. the proposed method include three processing steps: firstly, the thz-TDS image is preprocessed using a spatial vector filtering technique to denoise. Secondly, the thz-TDS image is transformed from spatio-temporal domain to spatio-spectral domain, and the transformed image can be viewed as a multispectralimage whose spectral dimensionality D is equal to the sampled number of thz-TDS pulse at each pixel. thirdly, each of spectrum vector at a pixel is viewed as a point in D dimensional space, the covariance matrix of pixels can be computed, and then three eigenvectors corresponding to the first 3 largest eigenvalues are found by PCA technique. the thz-TDS image is projected along these three eigenvectors. By normalizing these 3 principal component images and mapping them into the RGB space, we can get a synthetic color image as a visualization result of the thz-TDS image. Due to vector-based dimensionality reduction, the proposed method can provide more visual information of the thz-TDS imagethan scalar-based visualization techniques. Finally, experimental results are provided to demonstrate the performance of the proposed method.
the reflectance properties of a surface are an essential factor in its appearance. Much previous work has focused on the problem of reflectance recovery from images. these methods must assume an a priori grouping of p...
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ISBN:
(纸本)9780819469502
the reflectance properties of a surface are an essential factor in its appearance. Much previous work has focused on the problem of reflectance recovery from images. these methods must assume an a priori grouping of pixels into uniform-reflectance regions. In this paper we presented a method for automatic grouping of pixels for reflectance estimation. First a over-segmentation is achieved by traditional image segmentation. For each image region of the over-segmentation, a probability distribution is built and a reflectance subspace is formed by likelihood thresholding. the regions withthe same reflectance are then merged by adapting a traditional bayesian formulation for image segmentation to increase estimation accuacy. After completing the merging process, reflectance parameter estimates are computed for the remaining subspaces by the maximum likelihood reflectance estimate. the experiment results on a synthetic scene and a real scene show our method can achieve a more accurate image segmentation and reflectance estimation than traditional methods.
this paper describes an algorithm for automatic reference point detection in a top-view finger imagerecognition system. In tests of 700 finger images, only 6 images were rejected by our algorithm. A reference point l...
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ISBN:
(纸本)9789531841160
this paper describes an algorithm for automatic reference point detection in a top-view finger imagerecognition system. In tests of 700 finger images, only 6 images were rejected by our algorithm. A reference point location error correction technique was developed to improve the recognition accuracy. When using the proposed algorithm, the accuracy of the top-view finger image identification system was only reduced to 93.80% compared to 96.57% when using a manually defined reference point. this shows the feasibility of using top-view finger images to increase the recognition accuracy of fingerprint identification.
Local Polynomial Approximation-Intersection of Confidence Intervals (LPA-ICI) is a new approach, which can find the boundary of the isotropic region efficiently, especially for noisy images. this paper presents a nove...
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ISBN:
(纸本)9780819469502
Local Polynomial Approximation-Intersection of Confidence Intervals (LPA-ICI) is a new approach, which can find the boundary of the isotropic region efficiently, especially for noisy images. this paper presents a novel image denoising method, adaptive four windows wavelet image denoising based on LPA-ICI, which is composed of three parts: searching for four adaptive windows with LPA-ICI, updating the noisy wavelet coefficients by hard threshold and obtaining a final "clean" pixel value by fusing the updated pixels with different weights which are determined by the sparsity of regions. Experiments show that our algorithm has advanced performance, reconstructed edges are clean, and especially without unpleasant ringing artifacts.
Because Chan and Vese(C-V) model using one level set function can only represent one object and one background, it cannot represent multiple junctions of multiple objects. In this paper, an improved multi-object segme...
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ISBN:
(纸本)9780819469502
Because Chan and Vese(C-V) model using one level set function can only represent one object and one background, it cannot represent multiple junctions of multiple objects. In this paper, an improved multi-object segment algorithm is proposed based on C-V model of single level set. First, the given image resolution is deduced by wavelet transform. Since the low resolution approximate image contains less noise and pixels, it can speed up the active contour evolution. Secondly, an improved C-V model of a single level set is introduced to obtain the multi-objects' approximate contour, which can make use of topology split information of the contour effectively. thirdly, the inverse discrete wavelet transform is used to the resulted image and level set of the coarse scale image, which can get the approximation contour on the original image. Lastly, the approximation contour is taken as an initial level set function and the second active contour evolution is performed on the original image to get the real multi-objects contour. Experimental results show that the proposed algorithm can realize the multi-object segmentation effectively and quickly.
Because of the influence of speckle noise, it is difficult to extract the edge of the targets and locate the airport automatically in the low SNR real aperture radar imagery by the traditional ways. the paper presents...
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ISBN:
(纸本)9780819469502
Because of the influence of speckle noise, it is difficult to extract the edge of the targets and locate the airport automatically in the low SNR real aperture radar imagery by the traditional ways. the paper presents a kind of algorithms that could improve the dependability of the image matching and locate the airport target in the real aperture radar images. At first, the original real aperture radar imagery is enhanced on fuzzy property domain, which makes the airport target more prominent. then, the airport runway is detected using the Radon transform, and the end points and width of the airport runway are identified using the correlative knowledge of the airport. At last, the airport runway extracted is processed and the airport target is located withthe wavelet transform and the least square image matching. the experiment shows that the method could detect and locate the airport target well.
image segmentation is a difficult task. these years, researchers have proposed many segmentation methods based on Evolutionary Algorithms, but most of them used Evolutionary Algorithms to optimize the parameters of an...
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ISBN:
(纸本)9780819469502
image segmentation is a difficult task. these years, researchers have proposed many segmentation methods based on Evolutionary Algorithms, but most of them used Evolutionary Algorithms to optimize the parameters of an existing segmentation algorithm. this paper tries to use the Evolutionary Algorithms to segment images expecting to explore a new way of image segmentation. the method described in the paper pre-segments the image by Watersheds and then merges it by Immune Clonal Algorithm (ICA). To implement the task, several operators are proposed such as the DC operator, the Proportional Creation of the First generation operator, and fitness function based on JND and average gray value. In the end, the proposed method is compared with another method using GA. the experiments show that the method is effective and the work is significant.
the infrared ship segmentation in digital images is a fundamental step in the process of ship recognition. this paper presents an adaptive recursive algorithm for infrared ship image segmentation based on the gray-lev...
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ISBN:
(纸本)9780819469502
the infrared ship segmentation in digital images is a fundamental step in the process of ship recognition. this paper presents an adaptive recursive algorithm for infrared ship image segmentation based on the gray-level histogram analysis of the image. the proposed algorithm consists of four phases. First, the gray-level histogram of the image is generated and de-noised by using wavelets transform. Second, a threshold level which best extracts the ship from the water region is selected according to the histogram profile analysis. third, the rationality of the selected threshold is analyzed based on the prior information about infrared ship images. If the selected threshold is not reasonable, we can still use it as the recursive initial threshold and the infrared ship image will be further segmented with a local recursive method based on the method proposed by OTSU until it reaches the prescriptive termination criteria. Finally, we eliminate the spurious pixels by extracting the greatest connected region and filling the holes. the segmentation algorithm works successfully for classification of infrared ships, and some experimental results are also presented.
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