In this paper, two new techniques for differential detection of changes and motion in a set of images are proposed. The suggested techniques adopt an efficient parallel complementary encoding stage applied to the imag...
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In this paper, two new techniques for differential detection of changes and motion in a set of images are proposed. The suggested techniques adopt an efficient parallel complementary encoding stage applied to the image frames under study. These techniques profit from the optimum correlation properties of complete complementary code arrays. Simulation results are provided to demonstrate the efficient performance of the proposed techniques when applied to various types of images.
In this paper we examine and improve a new approach for changedetection (introduced in [1]) which is based on the appearance and disappearance of 3D line segments as seen in a new image. These 3D line segments are es...
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In this paper we examine and improve a new approach for changedetection (introduced in [1]) which is based on the appearance and disappearance of 3D line segments as seen in a new image. These 3D line segments are estimated from a set of learning images taken from arbitrary viewpoints and under arbitrary light conditions in an unsupervised manner. The main advantage of the proposed method lies in the fact that the changedetection is performed by comparing line segments, and not surfaces or gray levels. Computing 3D surfaces in an image can be computationally intensive, and other methods such as image subtraction or cross-correlation are sensitive to lighting conditions and changes in viewpoints. Moreover, most man-made objects such as buildings, cars, and even cities viewed from above consist mainly of straight linesman-made objects, and therefore this method is highly applicable for such structures. The proposed algorithm first focuses on the reconstruction of a set of 3D line segments forming a certain 3D scene using a set of 2D line segments obtained from the learning images in an unsupervised manner, without any prior knowledge on the cameras' positions or relative distance. In the changedetection stage, we use the reconstructed 3D scene of line segments to check if changes, such as appearance or disappearance of objects, have occurred in a given test image. This test image can be taken from arbitrary viewpoint and under arbitrary lighting conditions. Our changedetection algorithm not only distinguishes between the states of "changed" and "not-changed" line segments, it also classifies the "changed" line segments as appeared - objects that entered the scene in the test image, and disappeared - objects that left the 3D scene reconstructed from the lines of the learning images.
In this paper, an efficient moving object segmentation algorithm in the wavelet domain is proposed using three successive frames. The changedetection method, which employs fuzzy C-means clustering technique to classi...
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In this paper, an efficient moving object segmentation algorithm in the wavelet domain is proposed using three successive frames. The changedetection method, which employs fuzzy C-means clustering technique to classify motion features of four wavelet sub-bands, is used twice to separate significant change pixels in the wavelet domain from the background. After applying the intersect operation, the changedetection masks are obtained in wavelet domain. Finally, further object shape information and accurate extraction of the moving object is obtained in original resolution according to current object edge map. The experimental results demonstrate the algorithm effective
We present a scheme for automatically partitioning videos into scenes. A scene is generally referred to as a group of shots taken at the same site. We first propose a motion annotation algorithm based on the analysis ...
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ISBN:
(纸本)0769507506
We present a scheme for automatically partitioning videos into scenes. A scene is generally referred to as a group of shots taken at the same site. We first propose a motion annotation algorithm based on the analysis of spatiotemporal image volumes. The algorithm characterizes the motions within shots by extracting and analyzing the motion trajectories encoded in the temporal slices of image volumes. A motion-based keyframe computing and selection strategy is thus proposed to compactly represent the content of shots. With these techniques, we further present a scene changedetection algorithm by measuring the similarity of the representative keyframes in shots.
This paper attempts to perform on-line changedetection given time series data from unknown nonlinear dynamical systems. In the algorithm, the probability of occurrence of an abrupt change is estimated within a Bayesi...
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This paper attempts to perform on-line changedetection given time series data from unknown nonlinear dynamical systems. In the algorithm, the probability of occurrence of an abrupt change is estimated within a Bayesian framework. The implementation is done via sequential Monte Carlo (SMC). The proposed scheme is tested against two examples with nonlinear dynamical systems
Random phase noises arising from frequency jitter of transmit signal and atmospheric turbulence result in corrupted synthetic aperture radar (SAR) imagery, which in turn degrades changedetection (CD) performance. In ...
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Random phase noises arising from frequency jitter of transmit signal and atmospheric turbulence result in corrupted synthetic aperture radar (SAR) imagery, which in turn degrades changedetection (CD) performance. In this paper, a phase retrieval (PR) based SAR reconstruction autofocus framework by exploiting the hidden convexity is proposed with the goal of achieving reliable persistent surveillance CD. Firstly the original non-convex quartic SAR reconstruction is reformulated as a convex quadratic program. Under the minimum phase assumption, the auto-correlation retrieval- Kolmogorov factorization (CoRK) algorithm is then utilized to optimally and efficiently retrieve the underlying SAR reflectivity. The devised scheme possesses effective capabilities of phase noise mitigation, thus has a superior CD performance. Experimental results are provided to verify the effectiveness of the proposed method.
A key goal of the US Defense Department's Advanced Research Projects Agency Image Understanding program is to provide advanced vision systems to the military. This article describes two such IU projects; Radius, d...
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A key goal of the US Defense Department's Advanced Research Projects Agency Image Understanding program is to provide advanced vision systems to the military. This article describes two such IU projects; Radius, designed to aid intelligence image analysts, and UGV-RSTA, an IU system that enables an unmanned military ground vehicle to scout for enemy targets.
In dynamic spectrum access (DSA), unlicensed secondary users (SUs) estimate the idle probabilities of primary channels by using historical sensing results and opportunistically access the channel with the highest idle...
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In dynamic spectrum access (DSA), unlicensed secondary users (SUs) estimate the idle probabilities of primary channels by using historical sensing results and opportunistically access the channel with the highest idle probability for transmission. Due to the rapid traffic changes and irregular user mobility, primary channels can be highly dynamic and their idle probabilities are generally time-varying. In this paper, we investigate DSA in non-stationary environments. Specifically, we consider two channel state models, i.e., the non-stationary Bernoulli model with a time-varying mean and the non-stationary Markovian model with a time-varying transition matrix. For the single-SU scenario, we propose a Thompson sampling based method with a changedetection technique, which is capable of detecting the variations of channel statistics and adjusting the channel access strategy accordingly. For the multi-SU scenario, we propose a Thompson sampling based collision alleviation method to coordinate the transmissions of SUs, which does not need any prior protocol or information exchange among SUs. Numerical results show that the proposed methods outperform the existing ones in terms of successful transmission ratio in various network settings.
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