共查询到20条相似文献,搜索用时 31 毫秒
1.
The trace transform is a novel algorithm that has been shown to be effective in a number of image recognition tasks. It is
a generalisation of the Radon transform that has been widely used in image processing for decades. Its generality—allowing
multiple functions to be used in the mapping—leads to an algorithm that can be tailored to specific applications. However,
its computation complexity has been a barrier to its widespread adoption. By harnessing the heterogeneous resources on a modern
FPGA, the algorithm is significantly accelerated. Here, a flexible system is developed that allows for a wide array of functionals
to be computed without re-implementing the design. The system is fully scalable, such that the number and complexity of functionals
does not affect the speed of the circuit. The heterogeneous resources of the FPGA platform are then used to develop a set
of flexible functional blocks that can each implement a number of different mathematical functionals. The combined result
of this design is a system that can compute the trace transform on a 256 × 256 pixel image at 26 fps, enabling real-time processing
of captured video frames.
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2.
This paper presents a scheme and its Field Programmable Gate Array (FPGA) implementation for a system based on combining the
bi-dimensional discrete wavelet transformation (2D-DWT) and vector quantization (VQ) for image compression. The 2D-DWT works
in a non-separable fashion using a parallel filter structure with distributed control to compute two resolution levels. The
wavelet coefficients of the higher frequency sub-bands are vector quantized using multi-resolution codebook and those of the
lower frequency sub-band at level two are scalar quantized and entropy encoded. VQ is carried out by self organizing feature
map (SOFM) neural nets working at the recall phase. Codebooks are quickly generated off-line using the same nets functioning
at the training phase. The complete system, including the 2D-DWT, the multi-resolution codebook VQ, and the statistical encoder,
was implemented on a Xilinx Virtex 4 FPGA and is capable of performing real-time compression for digital video when dealing
with grayscale 512 × 512 pixels images. It offers high compression quality (PSNR values around 35 dB) and acceptable compression
rate values (0.62 bpp).
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3.
Using the multiple reference frames compensation in the H264 coder improves the coding efficiency for sequences which contain
uncovered backgrounds, repetitive motions and highly textured areas. Unfortunately this technique requires excessive memory
and computation resources. In this article, we proposed and implemented a technique based on Markov Random Fields Algorithm
relying on robust moving pixel segmentation. By the introduction of this technique, we were able to decrease the number of
reference frames from five to three while keeping similar video coding performances. The coding time decreased by 35% and
the sequence quality was preserved. After the validation of our idea, we evaluated the processing time of the Markov algorithm
on architectures intended for embedded multimedia applications. Both DSP and FPGA implementations were explored. We were able
to process 50 frames(128 × 128)/s on the EP1S10 FPGA paltform and 35 frames(128 × 128)/s on the ADSP BF533.
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4.
Documents and authors can be clustered into “knowledge communities” based on the overlap in the papers they cite. We introduce
a new clustering algorithm, Streemer, which finds cohesive foreground clusters embedded in a diffuse background, and use it
to identify knowledge communities as foreground clusters of papers which share common citations. To analyze the evolution
of these communities over time, we build predictive models with features based on the citation structure, the vocabulary of
the papers, and the affiliations and prestige of the authors. Findings include that scientific knowledge communities tend
to grow more rapidly if their publications build on diverse information and if they use a narrow vocabulary.
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5.
The watershed transformation is a popular image segmentation technique for gray scale images. This paper describes a real-time
image segmentation based on a parallel and pipelined watershed algorithm which is designed for hardware implementation. In
our algorithm: (1) pixels in a given image are repeatedly scanned from top-left to bottom-right, and then from bottom-right
to top-left, in order to achieve high performance on a pipelined circuit by simplifying memory access sequences, (2) all steps
in the algorithm are executed at the same time in the pipelined circuit, (3) the amount of data that are scanned is gradually
reduced as the calculation progresses by memorizing which data are modified in the previous scan, and (4) N pixels can be processed in parallel. In our current implementation on an off-the-shelf field-programmable gate array board,
up to four pixels can be processed in parallel. The performance for 512 × 512 pixel images is fast enough to be the first
step in real-time applications.
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6.
In this paper we present a novel hardware architecture for real-time image compression implementing a fast, searchless iterated
function system (SIFS) fractal coding method. In the proposed method and corresponding hardware architecture, domain blocks
are fixed to a spatially neighboring area of range blocks in a manner similar to that given by Furao and Hasegawa. A quadtree
structure, covering from 32 × 32 blocks down to 2 × 2 blocks, and even to single pixels, is used for partitioning. Coding
of 2 × 2 blocks and single pixels is unique among current fractal coders. The hardware architecture contains units for domain
construction, zig-zag transforms, range and domain mean computation, and a parallel domain-range match capable of concurrently
generating a fractal code for all quadtree levels. With this efficient, parallel hardware architecture, the fractal encoding
speed is improved dramatically. Additionally, attained compression performance remains comparable to traditional search-based
and other searchless methods. Experimental results, with the proposed hardware architecture implemented on an Altera APEX20K
FPGA, show that the fractal encoder can encode a 512 × 512 × 8 image in approximately 8.36 ms operating at 32.05 MHz. Therefore,
this architecture is seen as a feasible solution to real-time fractal image compression.
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7.
This paper presents an efficient VLSI architecture for fast implementation of sub-pixel interpolation of H.264/AVC. Several
optimization techniques at different design levels, such as parallel processing, vector register, pipeline architecture, and
in-place computation, are utilized to reduce the number of memory access and accelerate the interpolation computations. The
proposed application-specific processor can meet the real-time constraint of the sub-pixel interpolation algorithm for the
16:9 video format (4,690 × 2,304) at 30 frames per second (fps) at 100 MHz clock rate.
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8.
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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9.
This paper describes the simulated car racing competition that was arranged as part of the 2007 IEEE Congress on Evolutionary
Computation. Both the game that was used as the domain for the competition, the controllers submitted as entries to the competition
and its results are presented. With this paper, we hope to provide some insight into the efficacy of various computational
intelligence methods on a well-defined game task, as well as an example of one way of running a competition. In the process,
we provide a set of reference results for those who wish to use the simplerace game to benchmark their own algorithms. The paper is co-authored by the organizers and participants of the competition.
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10.
Clustering of time series subsequence data commonly produces results that are unspecific to the data set. This paper introduces
a clustering algorithm, that creates clusters exclusively from those subsequences that occur more frequently in a data set
than would be expected by random chance. As such, it partially adopts a pattern mining perspective into clustering. When subsequences
are being labeled based on such clusters, they may remain without label. In fact, if the clustering was done on an unrelated
time series it is expected that the subsequences should not receive a label. We show that pattern-based clusters are indeed
specific to the data set for 7 out of 10 real-world sets we tested, and for window-lengths up to 128 time points. While kernel-density-based
clustering can be used to find clusters with similar properties for window sizes of 8–16 time points, its performance degrades
fast for increasing window sizes.
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11.
Ohne Zusammenfassung
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12.
In this paper, we present an Inverse Multi-Objective Robust Evolutionary (IMORE) design methodology that handles the presence
of uncertainty without making assumptions about the uncertainty structure. We model the clustering of uncertain events in
families of nested sets using a multi-level optimization search. To reduce the high computational costs of the proposed methodology
we proposed schemes for (1) adapting the step-size in estimating the uncertainty, and (2) trimming down the number of calls
to the objective function in the nested search. Both offline and online adaptation strategies are considered in conjunction
with the IMORE design algorithm. Design of Experiments (DOE) approaches further reduce the number of objective function calls
in the online adaptive IMORE algorithm. Empirical studies conducted on a series of test functions having diverse complexities
show that the proposed algorithms converge to a set of Pareto-optimal design solutions with non-dominated nominal and robustness
performances efficiently.
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13.
Quantitative usability requirements are a critical but challenging, and hence an often neglected aspect of a usability engineering process. A case study is described where quantitative usability requirements played a key role in the development of a new user interface of a mobile phone. Within the practical constraints of the project, existing methods for determining usability requirements and evaluating the extent to which these are met, could not be applied as such, therefore tailored methods had to be developed. These methods and their applications are discussed. 相似文献
14.
The paper reflects on the unique experience of social and technological development in Lithuania since the regaining of independence
as a newly reshaped society constructing a distinctive competitive IST-based model at global level. This has presented Lithuanian
pattern of how to integrate different experiences and relations between generations in implementing complex information society
approaches. The resulting programme in general is linked to the Lisbon objectives of the European Union. The experience of
transitional countries in Europe, each different but facing some common problems, may be useful to developing countries in
Africa.
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15.
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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16.
The purposes of this study are (a) to establish a measurement for evaluating conversational impressions of group discussions,
and (b) to make an exploratory investigation on their interactional processes which may affect to form those impressions.
The impression rating and factor analysis undertaken first give us four factors concerning conversational impressions of “focus
group interviews (FGIs)”: conversational activeness, conversational sequencing, the attitudes of participants and the relationships
of participants. In relation to the factors of conversational activeness and conversational sequencing in particular, the
microanalysis of four selected topical scenes from our database further shows that the behavior of the moderator and the interviewees
is organized not independently but with reference to each other. The study thus emphasizes the importance of the integration
of quantitative and qualitative approaches towards human interactions.
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17.
We present a study of using camera-phones and visual-tags to access mobile services. Firstly, a user-experience study is described in which participants were both observed learning to interact with a prototype mobile service and interviewed
about their experiences. Secondly, a pointing-device task is presented in which quantitative data was gathered regarding the speed and accuracy with which participants aimed and clicked
on visual-tags using camera-phones. We found that participants’ attitudes to visual-tag-based applications were broadly positive,
although they had several important reservations about camera-phone technology more generally. Data from our pointing-device
task demonstrated that novice users were able to aim and click on visual-tags quickly (well under 3 s per pointing-device
trial on average) and accurately (almost all meeting our defined speed/accuracy tradeoff of 6% error-rate). Based on our findings,
design lessons for camera-phone and visual-tag applications are presented.
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18.
Awareness systems have attracted significant research interest for their potential to support interpersonal relationships.
Investigations of awareness systems for the domestic environment have suggested that such systems can help individuals stay
in touch with dear friends or family and provide affective benefits to their users. Our research provides empirical evidence
to refine and substantiate such suggestions. We report our experience with designing and evaluating the ASTRA awareness system,
for connecting households and mobile family members. We introduce the concept of connectedness and its measurement through
the Affective Benefits and Costs of communication questionnaire (ABC-Q). We inform results that testify the benefits of sharing
experiences at the moment they happen without interrupting potential receivers. Finally, we document the role that lightweight,
picture-based communication can play in the range of communication media available.
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19.
Assumptions are frequently made during requirements analysis of a system about the trustworthiness of its various components
(including human components). These trust assumptions, whether implicit or explicit, affect the scope of the analysis, derivation
of security requirements, and in some cases how functionality is realized. This paper presents trust assumptions in the context
of analysis of security requirements. A running example shows how trust assumptions can be used by a requirements engineer
to help define and limit the scope of analysis and to document the decisions made during the process. The paper concludes
with a case study examining the impact of trust assumptions on software that uses the secure electronic transaction specification.
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20.
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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