共查询到20条相似文献,搜索用时 31 毫秒
1.
The objective of this paper is to present an overall approach to forecasting the future position of the moving objects of
an image sequence after processing the images previous to it. The proposed method makes use of classical techniques such as
optical flow to extract objects’ trajectories and velocities, and autoregressive algorithms to build the predictive model.
Our method can be used in a variety of applications, where videos with stationary cameras are used, moving objects are not
deformed and change their position with time. One of these applications is traffic control, which is used in this paper as
a case study with different meteorological conditions to compare with.
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2.
Augmented reality (AR) is the concept of inserting virtual objects into real scenes. Often, augmentations are aligned with
rigid planar objects in the scene. However, a more difficult task is to align non-rigid augmentations with flexible objects
like cloth. To address this problem, we present a method to perform real-time flexible augmentations on cloth. Our method
involves sparse cloth-tracking in video images using a new vision-based marker system with temporal coherence. We include
an image-based method to automatically acquire real world illumination and shadows from the input frame. Non-rigid augmentations
are achieved by rendering a textured 2D mesh aligned with the cloth surface, and combining the illumination result. The ability
to perform realistic augmentations on cloth leads to applications in fashion, advertising, home decor and entertainment. We
demonstrate our cloth augmentations with an application to interactively design T-shirts by demonstrating different virtual
logos on a physical shirt in real-time.
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3.
We present a real-time implementation of 2D to 3D video conversion using compressed video. In our method, compressed 2D video
is analyzed by extracting motion vectors. Using the motion vector maps, depth maps are built for each frame and the frames
are segmented to provide object-wise depth ordering. These data are then used to synthesize stereo pairs. 3D video synthesized
in this fashion can be viewed using any stereoscopic display. In our implementation, anaglyph projection was selected as the
3D visualization method, because it is mostly suited to standard displays.
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4.
With low computation cost, motion vectors can be readily extracted from MPEG video streams and processed to estimate vehicle
motion speed. A statistical model is proposed to model vehicle speed and noise. In order to achieve high estimation accuracy
and also study the limitations of the proposed algorithm, we quantitatively evaluated four parameters used in our algorithm:
temporal filter window size T, video resolution R
v (CIF/QCIF), motion vector frame distance m, and video bit-rates. Our experiments showed that the mean vehicle speed can be estimated with high accuracy, up to 85 to
92% by proper spatial and temporal processing. The proposed algorithm is especially suitable for Skycam-based application,
where the traditional tracking-based or virtual-loop-based approaches perform poorly because of their requirements of high-resolution
images. Although extensive work has been done in extracting motion information directly from MPEG video data in compressed
domain, to our best knowledge, this paper is the very first work in which stationary motion (speed) of moving objects can
be estimated with high accuracy directly from MPEG motion vectors. Furthermore the proposed method is not limited to vehicle
speed estimation by nature and it can be applied to other applications where the stationary motion assumption is satisfied.
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5.
In this article, we deal with the problem of shot change detection which is of primary importance when trying to segment and
abstract video sequences. Contrary to recent experiments, our aim is to elaborate a robust but very efficient (real-time even
with uncompressed data) method to deal with the remaining problems related to shot change detection: illumination changes,
context and data independency, and parameter settings. To do so, we have considered some adaptive threshold and derivative
measures in a hue-saturation colour space. We illustrate our robust and efficient method by some experiments on news and football
broadcast video sequences.
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6.
We define a new birth and death dynamics dealing with configurations of disks in the plane. We prove the convergence of the
continuous process and propose a discrete scheme converging to the continuous case. This framework is developed to address
image processing problems consisting in detecting a configuration of objects from a digital image. The derived algorithm is
applied for tree crown extraction and bird detection from aerial images. The performance of this approach is shown on real
data.
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7.
This paper presents an FPGA implementation of a novel image enhancement algorithm, which compensates for the under-/over-exposed
image regions, caused by the limited dynamic range of contemporary standard dynamic range image sensors. The algorithm, which
is motivated by the attributes of the shunting center-surround cells of the human visual system, is implemented in Altera
Stratix II GX: EP2SGX130GF1508C5 FPGA device. The proposed implementation, which is synthesized in an FPGA technology, employs
reconfigurable pipeline, structured memory management, and data reuse in spatial operations, to render in real-time the huge
amount of input data that the video signal comprises. It also avoids the use of computationally intensive operations, achieving
the required specifications in terms of flexibility, timing, performance and visual quality. The proposed implementation allows
real-time processing of color images with sizes up to 2.5 Mpixels, at frame rate of 25 fps. As a result, the architectural
solution described in this work offers a low-cost implementation for automatic exposure correction in real-time video systems.
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8.
This paper deals with monitoring user perception of multimedia presentations in a Universal Multimedia Access (UMA) enabled
system using objective no-reference (NR) metrics. These NR metrics are designed for an UMA-enabled system, in a novel architecture,
for a multimedia viewer. The first metric measures block-edge impairments in a video frame at the receiver end, based on the
observation that they occur in regions with low spatial activity. The second metric evaluates the quality of the reconstructed
video frame in the event of packet loss. Here, the structure of the artifact is itself exploited for the evaluation. Both
the metrics involve low computational complexity and are feasible for real-time monitoring of streaming video in a multimedia
communication scenario. Further, in rate-adaptive streaming of video, these metrics could serve as feedback parameters to
dynamically adapt the bit rates based on network congestion.
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9.
In conventional motion compensated temporal filtering based wavelet coding scheme, where the group of picture structure and
low-pass frame position are fixed, variations in motion activities of video sequences are not considered. In this paper, we
propose an adaptive group of picture structure selection scheme, which the group of picture size and low-pass frame position
are selected based on mutual information. Furthermore, the temporal decomposition process is determined adaptively according
to the selected group of picture structure. A large amount of experimental work is carried out to compare the compression
performance of proposed method with the conventional motion compensated temporal filtering encoding scheme and adaptive group
of picture structure in standard scalable video coding model. The proposed low-pass frame selection can improve the compression
quality by about 0.3–0.5 dB comparing to the conventional scheme in video sequences with high motion activities. In the scenes
with un-even variation of motion activities, e.g. frequent shot cuts, the proposed adaptive group of picture size can achieve
a better compression capability than conventional scheme. When comparing to adaptive group of picture in standard scalable
video coding model, the proposed group of picture structure scheme can lead to about 0.2~0.8 dB improvements in sequences
with high motion activities or shot cut.
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10.
There are only a few ethical regulations that deal explicitly with robots, in contrast to a vast number of regulations, which
may be applied. We will focus on ethical issues with regard to “responsibility and autonomous robots”, “machines as a replacement
for humans”, and “tele-presence”. Furthermore we will examine examples from special fields of application (medicine and healthcare,
armed forces, and entertainment). We do not claim to present a complete list of ethical issue nor of regulations in the field
of robotics, but we will demonstrate that there are legal challenges with regard to these issues.
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11.
In this paper, we study the important issues in the design of an efficient wireless real-time visual surveillance system (WISES).
Two important considerations are to minimize: (1) the video workload on the wireless network; and (2) the processing workload
at the front-end video capturing unit. To achieve the first objective, we propose a cooperative framework for semantic filtering of video frames instead of forwarding every video frame to the back-end server for analysis and monitoring query evaluation.
To minimize the processing workload at the front-end unit, a hierarchical object model (HOM) is designed to model the status
of the objects, and their temporal and spatial properties in the video scene. With the information provided from the back-end
server, the front-end unit pre-analyses the current status of the objects in the HOM by comparing the selection conditions
in the submitted monitoring queries following the adaptive object-based evaluation (APOBE) scheme which is proposed to reduce
the processing workload at the front-end unit. In APOBE, a higher evaluation frequency is given to the object which is closer
to satisfy the condition in the monitoring queries. The performance of WISES has been studied to demonstrate the efficiency
of the proposed scheme.
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12.
A software system Gel Analysis System for Epo (GASepo) has been developed within an international WADA project. As recent
WADA criteria of rEpo positivity are based on identification of each relevant object (band) in Epo images, development of
suitable methods of image segmentation and object classification were needed for the GASepo system. In the paper we address
two particular problems: segmentation of disrupted bands and classification of the segmented objects into three or two classes.
A novel band projection operator is based on convenient object merging measures and their discrimination analysis using specifically
generated training set of segmented objects. A weighted ranks classification method is proposed, which is new in the field
of image classification. It is based on ranks of the values of a specific criterial function. The weighted ranks classifiers
proposed in our paper have been evaluated on real samples of segmented objects of Epo images and compared to three selected
well-known classifiers: Fisher linear classifier, Support Vector Machine, and Multilayer Perceptron.
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13.
This paper describes a segmentation method combining a texture based technique with a contour based method. The technique
is designed to enable the study of cell behaviour over time by segmenting brightfield microscope image sequences. The technique
was tested on artificial images, based on images of living cells and on real sequences acquired from microscope observations
of neutrophils and lymphocytes as well as on a sequence of MRI images. The results of the segmentation are compared with the
results of the watershed and snake segmentation methods. The results show that the method is both effective and practical.
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14.
The Mumford-Shah functional and related algorithms for image segmentation involve a tradeoff between a two-dimensional image
structure and one-dimensional parametric curves (contours) that surround objects or distinct regions in the image.
We propose an alternative functional that is independent of parameterization; it is a geometric functional given in terms
of the surfaces representing the data and image in the feature space. The Γ-convergence technique is combined with the minimal
surfaces theory to yield a global generalization of the Mumford-Shah segmentation function.
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15.
The objective measurement of blocking artifacts plays an important role in the design, optimization, and assessment of image
and video compression. In this paper, we propose a novel measurement algorithm for blocking artifacts. Computer simulation
results indicate that the proposed method accurately measures the blocking artifacts without using the original image. Moreover,
the proposed algorithm can be easily implemented in both pixel and DCT domains.
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16.
The complexity of group dynamics occurring in small group interactions often hinders the performance of teams. The availability
of rich multimodal information about what is going on during the meeting makes it possible to explore the possibility of providing
support to dysfunctional teams from facilitation to training sessions addressing both the individuals and the group as a whole.
A necessary step in this direction is that of capturing and understanding group dynamics. In this paper, we discuss a particular
scenario, in which meeting participants receive multimedia feedback on their relational behaviour, as a first step towards
increasing self-awareness. We describe the background and the motivation for a coding scheme for annotating meeting recordings
partially inspired by the Bales’ Interaction Process Analysis. This coding scheme was aimed at identifying suitable observable
behavioural sequences. The study is complemented with an experimental investigation on the acceptability of such a service.
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17.
There is rapidly increasing interest in Location Based Service (LBS) which utilizes location data of moving objects. To efficiently
manage the huge amounts of location data in LBS, the GALIS (Gracefully Aging Location Information System) architecture, a
cluster-based distributed computing architecture, is proposed. The GALIS using the non-uniform 2-level grid algorithm performs
load balancing and indexing for nodes. However, the non-uniform 2-level grid algorithm has a problem creating unnecessary
nodes when moving objects are crowded in a certain region. Therefore, a new node split algorithm, which is more efficient
for various distribution of moving objects, is proposed in this paper. Because the algorithm proposed in this paper considers
spatial distribution for the current location of moving objects, it can perform efficient load balancing without creating
unnecessary nodes even when moving objects are congested in a certain region. Besides, the various data distribution configuration
for moving objects has been experimented by implementing node split simulators and it’s been verified that the proposed algorithm
can split nodes more efficiently than the existing algorithm.
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18.
This paper addresses the modeling of the static and dynamic parts of the scenario and how to use this information with a sensor-based
motion planning system. The contribution in the modeling aspect is a formulation of the detection and tracking of mobile objects
and the mapping of the static structure in such a way that the nature (static/dynamic) of the observations is included in
the estimation process. The algorithm provides a set of filters tracking the moving objects and a local map of the static
structure constructed on line. In addition, this paper discusses how this modeling module is integrated in a real sensor-based
motion planning system taking advantage selectively of the dynamic and static information. The experimental results confirm
that the complete navigation system is able to move a vehicle in unknown and dynamic scenarios. Furthermore, the system overcomes
many of the limitations of previous systems associated to the ability to distinguish the nature of the parts of the scenario.
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19.
An interesting issue in moving object databases is to find similar trajectories of moving objects. Previous work on this topic
focuses on movement patterns (trajectories with time dimension) of moving objects, rather than spatial shapes (trajectories
without time dimension) of their trajectories. In this paper we propose a simple and effective way to compare spatial shapes
of moving object trajectories. We introduce a new distance function based on “one way distance” (OWD). Algorithms for evaluating
OWD in both continuous (piece wise linear) and discrete (grid representation) cases are developed. An index structure for
OWD in grid representation, which guarantees no false dismissals, is also given to improve the efficiency of similarity search.
Empirical studies show that OWD out-performs existent methods not only in precision, but also in efficiency. And the results
of OWD in continuous case can be approximated by discrete case efficiently.
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20.
In this paper, we propose a new real-time content filtering framework for live broadcasts in TV terminals. Content filtering
in TV terminals is a necessary provision of personalized broadcasting services in that it enables a TV viewer to obtain desired
scenes from multiple channel broadcasts. In this paper, a stable and reliable filtering structure and an algorithm for multiple
inputs are proposed. Moreover, real-time filtering requirements such as frame sampling rate per channel, number of input channels,
and buffer condition are analyzed to achieve real-time processing in terminals with limited computing power. Based on queueing
theory, we model the system and resolve the filtering requirements. To verify the proposed system and analysis, a filtering
algorithm for soccer videos is applied which is modified for real-time processing. Through analysis of visual features (e.g.,
dominant color and edge components) and detection of spatial objects (e.g., a score board), it recognizes a temporal pattern
between successive video frames and filters desired scenes. Experiments on soccer videos have been performed and the results
validate the effectiveness of the proposed approach and system.
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