In the paper, we present a new surface rendering method using a modified contour matching algorithm. The algorithm is based on the invariance of curvature after rotating or displacement. Using the description of conto...
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In the paper, we present a new surface rendering method using a modified contour matching algorithm. The algorithm is based on the invariance of curvature after rotating or displacement. Using the description of contour by curvature, the problem of contour matching in 2D is converted into a 1D problem. Therefore it decreases the computational cost. In the computing, we compared two kinds of numerical algorithms, i.e. predictor-corrector scheme and successive over relaxation (SOR). Finally, we introduce a 3D surface rendering proc.dure employing the contour matching.
Variations in illumination can have a dramatic effect on the appearance of an object in an image. In this paper we propose how to deal with illumination variations in eigenspace methods. We demonstrate that the eigeni...
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Variations in illumination can have a dramatic effect on the appearance of an object in an image. In this paper we propose how to deal with illumination variations in eigenspace methods. We demonstrate that the eigenimages obtained by a training set under a single illumination condition (ambient light) can be used for recognition of objects taken under different illumination conditions. The major idea is to incorporate a set of gradient based filter banks into the eigenspace recognition framework. This can be achieved since the eigenimage coefficients are invariant for linearly filtered images (input and eigenimages). To achieve further illumination insensitivity we devised a robust proc.dure for coefficient recovery. The proposed approach has been extensively evaluated on a set of 2160 images and the results were compared to other approaches.
The concept of occlusion mesh model is introduced. A novel object tracking algorithm based on occlusion mesh model is proposed. A modified occlusion detection method is considered to improve the detection accuracy. Me...
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ISBN:
(纸本)0780375084
The concept of occlusion mesh model is introduced. A novel object tracking algorithm based on occlusion mesh model is proposed. A modified occlusion detection method is considered to improve the detection accuracy. Mesh nodes motion estimation method based on feature window matching is presented to achieve sub-pixel resolution and overcome block artifacts produced by block matching. Experiment results indicate that the proposed algorithm is practical and feasible, it can be used to object tracking effectively. Also it solves 2D motion estimation problem existed in occlusion regions and shows better visual performance.
Multisensor image registration is a difficult problem. In this paper, we give a new registration method using direct histogram specification technique. We find that after using histogram specification, the resulting i...
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ISBN:
(纸本)0780381939
Multisensor image registration is a difficult problem. In this paper, we give a new registration method using direct histogram specification technique. We find that after using histogram specification, the resulting images with the same view look more similar, though the original images gained by different sensors differ much in intensity. Based on this property, a novel approach to find matching block pairs is proposed. The centers of the block pairs are used as control points (cps). We also use the cluster method of the nearest function criterion to test the correctness of the cps and discard wrong ones. The algorithm has been tested by many aerial images of different sensors. The effectiveness is illustrated by the experimental results.
Guided by a building concept model, which interprets building into different levels and scales, this paper presents a method to extract buildings in monocular urban aerial images without priori illuminating or orienta...
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ISBN:
(纸本)0780381939
Guided by a building concept model, which interprets building into different levels and scales, this paper presents a method to extract buildings in monocular urban aerial images without priori illuminating or orientation knowledge. By using a shadow context model, a method was proposed to estimate the direction of shadow cast to verify the raw segmentations. Building extractions are refined by context, and a method of partial snake with the aid of the shadow cast direction is proposed, which can sharply reduce the iteration complexity and the influence caused by illumination. The extraction of self-shadow on gable roof with a proposed mathematical roof model is also discussed in this paper.
In this paper, we investigate how camera pose can be estimated from 2D to 3D corner correspondence when vertex of the corner is occluded. We show that the image coordinate of the occluded vertex can be easily estimate...
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In this paper, we investigate how camera pose can be estimated from 2D to 3D corner correspondence when vertex of the corner is occluded. We show that the image coordinate of the occluded vertex can be easily estimated from the image edge lines by an analytical method. Then the camera pose parameters can be recovered from 2D to 3D correspondences of the corner and a nonsingular point on it over a single view. A ground truth comparison is made by experiments using controlled scenes, which shows that the method is promising.
We present a generic and robust image analysis approach applicable to image data resulting from a broad class of hybridization experiments. The ultimate image analysis goal is to automatically assign a quantity to eve...
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We present a generic and robust image analysis approach applicable to image data resulting from a broad class of hybridization experiments. The ultimate image analysis goal is to automatically assign a quantity to every array element (spot), giving information about the hybridization signal. Irrespective of the quantification strategy, the most important preliminary information to extract about a spot is the mapping between its location in the digital image and its position in the spot grid (grid fitting). We present a grid fitting approach divided into a spot amplification step (matched filter), a rotation estimation step (Radon transform) and a grid spanning step. Quantification of the hybridization signals is performed with different fitting approaches. The primary approach is a robust fitting of a parametric model with the help of M-estimators. The main advantage of parametric spot fitting is its ability to cope with overlapping spots. If the goodness-of-fit is too bad, a semi-parametric spot fitting is employed.
A novel method for spectral similarity measure, which is called nonlinear spectral similarity measure, is presented in this paper. In this method, all original spectral vectors are, firstly, nonlinearly transformed in...
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A novel method for spectral similarity measure, which is called nonlinear spectral similarity measure, is presented in this paper. In this method, all original spectral vectors are, firstly, nonlinearly transformed into a feature space. Next, kernel PCA is used to construct a set of orthogonal coordinate base in feature space. All transformed spectral vectors are projected onto the orthogonal coordinate space. In kernel principal component analysis (KPCA), the nonlinear translation function is implicatively implemented by kernel function. Moreover, all projected spectral vectors are constrained by spectral continuum removal curve. Because of continuum removal curve, various bands contribute the similar measurement in different. The more absorption is the more the contribution in similarity measurement. At last, linear or general linear similarity measure, for example spectral angle mapper, was used to measure the similarity between two nonlinearly transformed spectra. Our experiments show that this method is effective in spectral similarity measure.
An initial estimates method for calibration of a robotic hand-eye relationship is presented in the paper. Classical methods mainly concentrate on solving the basic equation AX = XB, where X is the unknown sensor posit...
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ISBN:
(纸本)078038296X
An initial estimates method for calibration of a robotic hand-eye relationship is presented in the paper. Classical methods mainly concentrate on solving the basic equation AX = XB, where X is the unknown sensor position rel ative to the robot hand, A is the robot motion, B is the camera motion. In optimizing proc.ss of solving the equation, initial values are needed. Unsuitable initial values often lead to a big error. The proposed method has a large advantage on getting a fine initial value, which can avoid errors introduced by experience effectively. Real experiments have been used to test the proposed method and good results have been obtained.
Extraction of Video Object Plane (VOP) is the central challenge for content-based video proc.ssing. It enables separate and flexible manipulation, blending and arrangement of content at MPEG-4 based decoder. In this p...
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ISBN:
(纸本)0780384032
Extraction of Video Object Plane (VOP) is the central challenge for content-based video proc.ssing. It enables separate and flexible manipulation, blending and arrangement of content at MPEG-4 based decoder. In this paper, we present a fast and efficient extraction algorithm depending on Edge Detection. Our algorithm begins with finding edge candidates detected by Canny Edge Detector. After selecting edge pixels which belong to the moving object in current frame, the VOP is extracted by using morphological operations. The proposed algorithm is evaluated on MPEG-4 test sequence and generates desirable VOPs at a lower computation cost.
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