检索结果-内蒙古大学图书馆

Foreground segmentation for dynamic scenes with sudden illumination changes

IET image processing 2012年第5期6卷 606-615页

作者： Li, J. Miao, Z. Beijing Jiaotong Univ Inst Informat Sci Beijing Peoples R China

Foreground segmentation is a very difficult task in dynamic background, which is common in real-world environments, caused by for example waving foliage, rippling water or illumination changes owing to light switching etc. A large number of methods for foreground segmentation in dynamic background have been proposed in the past decades, but most of them can only handle repetitive movements or gradual changes in background, and fail when sudden illumination changes occur. This study proposes a new method, which can deal with both repetitive movements and gradual/sudden illumination changes. The authors use a two-layer Gaussian mixture model to represent the background under different lighting conditions and formulate a joint posterior function of background state and segmentation based on the learned model. Given a new image, the background state and foreground segmentation are simultaneously optimised in a Bayesian perspective using a nested two-layer optimisation. The authors test their method on several image sequences and compare the results qualitatively and quantitatively with some state-of-the-art methods to demonstrate the effectiveness of the method.

关键词： two-layer Gaussian mixture model gradual-sudden illumination change computer vision and image processing techniques lighting waving foliage background state light switching dynamic scene foreground segmentation Bayesian perspective Gaussian processes Optical, image and video signal processing image segmentation rippling water nested two-layer optimisation joint posterior function image sequences Bayes methods Other topics in statistics image sequence

来源：评论

学校读者我要写书评

暂无评论

Super-resolution using an enhanced Papoulis-Gerchberg algorithm

引用

IET image processing 2012年第7期6卷 959-965页

作者： Salari, E. Bao, G. Univ Toledo Dept Elect Engn & Comp Sci Toledo OH 43606 USA

Super resolution (SR) is the process of generating a raster image with a higher resolution than its source. The Papoulis-Gerchberg (P-G) algorithm known as one of the most important approaches of signal reconstruction, has been extensively used to reconstruct high-resolution information from low-resolution images by imposing spatial and frequency domain constraints in an iterative process. Although this procedure is easy to implement, it converges slowly and requires pre-knowledge of the image bandwidth. To overcome these problems, a new procedure is proposed, to enhance the original P-G algorithm in terms of speed and performance, by using dynamic properties in the frequency domain. The proposed technique also allows an automatic adjustment of the bandwidth during each iteration. computer simulations are given to illustrate the effectiveness of the proposed method.

关键词： image resolution frequency-domain analysis computer vision and image processing techniques iterative process P-G algorithm Optical, image and video signal processing low-resolution images iterative methods frequency-domain constraints high-resolution information reconstruction computer simulations enhanced Papoulis-Gerchberg algorithm signal reconstruction raster image superresolution Interpolation and function approximation (numerical analysis) image bandwidth image reconstruction

来源：评论

学校读者我要写书评

暂无评论

Illumination compensation for nominally planar surface recovery

引用

IET computer vision 2012年第5期6卷 371-377页

作者： Sun, J. Smith, M. Smith, L. Farooq, A. Univ W England Machine Vis Lab Bristol BS16 1QY Avon England

A uniform distribution of illumination radiance across the surface of objects of interest is desired for most scene analysis approaches, including that of photometric stereo. Either specially designed parallel illumination or distant point light sources have been used to fulfil this requirement. However, there can be significant practical difficulties in achieving such idealised parallel light sources in real world applications, where setup space may be constrained and only generally available lights and lighting condition are provided. To solve this important but often overlooked problem, a flat reference object is proposed to sample the uneven incident lighting condition in order to allow the illumination radiance factor at every individual pixel to be cancelled out for the given scene analysis task. Experiments show that the proposed strategy can improve the accuracy of the photometric stereo method for reconstructing nominally planar surfaces containing topographic relief, even when normal low-cost commercial light sources are used.

关键词： uniform distribution image reconstruction photometry scene analysis approach illumination radiance factor photometric stereo method nominally planar surface reconstruction lighting topographic relief illumination compensation nominally planar surface recovery scene analysis task parallel illumination computer vision and image processing techniques Optical, image and video signal processing flat reference object stereo image processing

来源：评论

学校读者我要写书评

暂无评论

Fast tracking algorithm using modified potential function

引用

IET computer vision 2012年第2期6卷 111-120页

作者： Kapoor, R. Dhamija, A. Delhi Technol Univ Dept Elect & Commun Engn Delhi 42 India YMCA Univ Sci & Technol Dept Elect Engn Faridabad Haryana India

This study introduces a new potential function-based modelling approach for real-time object tracking with single camera. Real-time tracking requires the least complex techniques for processing and classification and still provide accurate results. Particle filter-based algorithms allow accurate estimations of the displacement and scaling of the object for tracking, but at the cost of high computational complexity and complicated modelling. Also, the existing single-camera tracking systems lack the ability to predict the direction of motion of the object and their performance is significantly affected by occlusions. This study proposes a new method to address these four key issues. The method is principally based upon the potential function, which has been modified for motion image sequences. Potential function uses the current estimates of nonlinear scaling and drift vector with a priori knowledge of the object to compute the tracking parameters in the form of diffusion matrices. The concept of attractors and repellers inside a potential field has been used in analogy to classify different directions of motion in the image plane, such that the object tends to drift towards the attractors and away from repellers. Attractor for every consecutive pair of frames is estimated using the set of transformations (displacement and scaling) occurred due to the motion in a particular direction. The proposed technique works well with minimal tracking errors and a computational complexity of O(1).

关键词： least complex techniques real-time tracking diffusion matrices cameras computational complexity fast tracking algorithm modified potential function image sequences potential function-based modelling approach matrix algebra particle filter-based algorithms Algebra object tracking motion image sequences drift vector Optical, image and video signal processing image classification computer vision and image processing techniques Filtering methods in signal processing image sensors image motion analysis minimal tracking errors image plane single-camera tracking systems nonlinear scaling particle filtering (numerical methods) real-time object tracking

来源：评论

学校读者我要写书评

暂无评论

New adaptive steganographic method using least-significant-bit substitution and pixel-value differencing

引用

IET image processing 2012年第6期6卷 677-686页

作者： Khodaei, M. Faez, K. Islamic Azad Univ Qazvin Dept Elect & IT & Comp Engn Qazvin Iran Amirkabir Univ Technol Dept Elect Engn Tehran Iran

This study presents a new adaptive data-hiding method based on least-significant-bit (LSB) substitution and pixel-value differencing (PVD) for grey-scale images. The proposed method partition the cover image into some non-overlapping blocks having three consecutive pixels and select the second pixel of each block as the central pixel (called base-pixel). Then, k-bits of secret data are embedded in the base pixel by using LSB substitution and optimal pixel adjustment process (OPAP). The difference between the base-pixel value and other pixel values in the block are utilised to determine how many secret bits can be embedded in the two pixels. Also, the method divides all possible differences into lower level and higher level with a number of ranges. Then, it obtains the number of the secret bits that will be embedded into each block depending on the range which the difference values belong to. The experimental results show that the proposed method can embed a large amount of secret data while maintaining a high visual quality of the stego-images. The peak signal-to-noise ratio (PSNR) values and the embedding capacity of our method are higher than those of three other data-hiding methods which are investigated in this study.

关键词： adaptive data-hiding method image colour analysis embedding capacity base-pixel computer vision and image processing techniques image and video coding grey-scale image central pixel image coding Cryptography optimal pixel adjustment process peak signal-to-noise ratio value LSB substitution least-significant-bit substitution pixel-value differencing adaptive steganographic method stego-image steganography Data security

来源：评论

学校读者我要写书评

暂无评论

Hardware-software co-design architecture for Joint Photo Expert Graphic XR encoder

引用

IET image processing 2012年第9期6卷 1284-1292页

作者： Tseng, C. -F. Lai, Y. -T. Natl Cheng Kung Univ Dept Elect Engn Tainan 701 Taiwan

In recent years, because of to the fast growing of internet and digital multi-media, new image compression algorithms are needed to reduce the transferring bandwidth and the decay of image quality. Joint Photo Expert Graphic (JPEG) extended range (XR) is a new standard for still image compression. Compared to previous standards, it provides better image quality and plentiful pixel format. However, the better image quality often comes with the higher computation complexity. In this study, the authors propose a hardware-software co-design architecture for JPEG XR encoder. For photo overlap transform (POT), and photo core transform (PCT), the complicated parts of JPEG XR, the authors propose new algorithms which eliminate data dependency in the basic filters of POT and PCT so that operations can be executed in parallel. The processing rate of the new algorithms is much faster. The authors also demonstrate a basic filter with multiple functions, which can be time-shared by POT and PCT;the hardware cost can be therefore reduced. Moreover, a memory saving scheme is proposed. Therefore the proposed architecture is suitable for stand-alone application-specific integrated circuit (ASIC). In our co-design, POT and PCT are implemented in hardware and then mapped to field programmable gate array (FPGA), whereas the other procedures of JPEG XR such as quantisation are executed by ARM926-EJ processor. The overall performance of our hardware architecture is 50 fps for 4:4:4 HDTV format at 166 MHz.

关键词： frequency 166 MHz image quality ASIC Filtering methods in signal processing photo core transform ARM926-EJ processor data compression hardware-software codesign digital multimedia image compression algorithm JPEG XR encoder field programmable gate arrays Hardware-software codesign Internet Electronic engineering computing FPGA joint photo expert graphic XR encoder computer vision and image processing techniques computer architecture image and video coding still image compression application specific integrated circuits image coding hardware architecture photo overlap transform data dependency Integral transforms POT quantisation (signal) Logic circuits computer architecture computation complexity quantisation JPEG extended range stand-alone application-specific integrated circuit PCT Logic and switching circuits memory saving scheme HDTV format filtering theory filter bandwidth transfer hardware-software co-design architecture field programmable gate array Digital circuit design, modelling and testing transforms

来源：评论

学校读者我要写书评

暂无评论

Automated region-based hybrid compression for digital imaging and communications in medicine magnetic resonance imaging images for telemedicine applications

引用

IET SCIENCE MEASUREMENT & TECHNOLOGY 2012年第4期6卷 247-253页

作者： Bairagi, V. K. Sapkal, A. M. Sinhgad Acad Engn Dept Elect & Telecom Engn Pune Maharashtra India Coll Engn Dept Elect & Telecom Engn Pune Maharashtra India

Many classes of images contains spatial regions which are more important than other regions. Compression methods which are capable of delivering higher reconstruction quality are attractive in this situation for the important parts. For the medical images, only a small portion of the image might be diagnostically useful, but the cost of a wrong interpretation is high. Hence, Region Based Coding (RBC) technique is significant for medical image compression and transmission. Lossless compression in these 'regions' and lossy compression for rest of image can helps to achieve high efficiency and performance in telemedicine applications. This paper proposes an automated, efficient and low complexity, lossless, scalable RBC for Digital Imaging and Communications in Medicine (DICOM) images. The advantages of RBC are exploited in this paper, segmenting the region into various regions of importance and subjecting varying bit-rates for optimal performance. Moreover, the combined effects of Integer Wavelet Transform (IWT) and bit-rate limiting compression technique for lesser important regions helps reconstruct the image, reversibly, up to a desired quality. The overall compression thus reaches a satisfactory level to be able to safely transmit the image in limited bandwidth over a telemedicine network and reconstruct diagnostic details for treatment, most faithfully.

关键词： computer vision and image processing techniques Biomedical magnetic resonance imaging and spectroscopy data compression image and video coding medical images Biology and medical computing wavelet transforms Biomedical communication automated region based hybrid compression digital imaging medicine magnetic resonance imaging image biomedical MRI telemedicine medical image compression image coding medical image processing lossless compression DICOM patient diagnosis integer wavelet transform Integral transforms in numerical analysis Patient diagnostic methods and instrumentation telemedicine applications region based coding technique image processing and restoration image transmission Function theory, analysis Medical magnetic resonance imaging and spectroscopy bit rate limiting compression technique

来源：评论

学校读者我要写书评

暂无评论

New image quality metric using random projection

引用

IET image processing 2012年第9期6卷 1246-1255页

作者： Kim, D. -O Park, R. -H. Sogang Univ Dept Elect Engn Seoul 121742 South Korea

This study proposes a new image quality metric using random projection (RP). Generally, distortion is wide spread over the entire region in an image when the image is degraded by compression, blurring, additive noise and so on, which signifies that it is not necessary to compute the degree of distortion at every pixel. RP has been used for representing a signal to a small number of measurements. In this study, to evaluate image quality, distortions between the reference and distorted images are measured at a small number of pixels that are preselected or randomly chosen through the RP and to beat the simple random sampling, the saliency-based weighted sum is used. Experimental results with the laboratory for image and video engineering data set show the effectiveness of the proposed quality metric.

关键词： additive noise video engineering data set blurring computer vision and image processing techniques reference image random projection distorted image image and video coding image coding image compression image quality metric saliency-based weighted sum data compression

来源：评论

学校读者我要写书评

暂无评论

Colour image watermarking for tamper proofing and pattern-based recovery

引用

IET image processing 2012年第5期6卷 445-454页

作者： Liu, K. -C. Information Educating Center Taiwan Hospitality and Tourism College Taiwan

The rapid development of the internet allows digital media being easily delivered, copied and even tampered. The watermarking issue has thus focused mainly on the medium of authentication. In this study, an efficient self-embedding watermarking scheme for colour image authentication is proposed. The scheme is designed to achieve tamper proofing and high-quality recovery. The scheme is efficient because the validity of image blocks is simply proofed by using a dual-option parity-check method and morphological operations. The former is used to generate authentication information for obtaining better results of tamper proofing and the latter is used to further improve the neighbouring connectivity of the proofing results. To achieve high-quality recovery of the tampered image, the feature information of the host colour image and its corresponding block-edge-pattern information are properly organised to embed into three colour components of the host colour image. Meanwhile, the embedding information is appropriately distributed over luminance and chrominance components of the colour image in the YCbCr colour space such that the quality of the watermarked image can be better obtained. The simulation results show that the proposed watermarking scheme can effectively proof the tempered region with high detection rate and can restore the tempered region with high quality.

关键词： image colour analysis Internet computer vision and image processing techniques tamper proofing image watermarking image and video coding image block validity image coding colour image authentication information high-quality pattern-based recovery high-quality recovery self-embedding watermarking scheme feature information dual-option parity-check method morphological operation digital media image sensors colour image watermarking Data security chrominance component luminance component block-edge-pattern information

来源：评论

学校读者我要写书评

暂无评论

Critical analysis of adaptive biometric systems

引用

IET BIOMETRICS 2012年第4期1卷 179-187页

作者： Poh, N. Rattani, A. Roli, F. Univ Surrey FEPS Dept Comp Guildford GU2 5XH Surrey England Univ Cagliari Piazza dArmi Dept Elect & Elect Engn Cagliari Italy

Biometric-based person recognition poses a challenging problem because of large variability in biometric sample quality encountered during testing and a restricted number of enrollment samples for training. Solutions in the form of adaptive biometrics have been introduced to address this issue. These adaptive biometric systems aim to adapt enrolled templates to variations in samples observed during operations. However, despite numerous advantages, few commercial vendors have adopted auto-update procedures in their products. This is due in part to the limited understanding and limitations associated with existing adaptation schemes. In view of that the topic of adaptive biometrics has not been systematically investigated, this study works towards filling this gap by surveying the topic from a growing body of the recent literature and by providing a coherent view (critical analysis) of the limitations of the existing systems. In addition, the authors have also identified novel research directions and proposed a novel framework. The overall aim is to advance the state-of-the-art and improve the quality of discourse in this field.

关键词： critical analysis biometric-based person recognition adaptive systems biometrics (access control) image recognition image recognition learning biometric sample quality adaptive biometric system sample variation autoupdate procedure learning (artificial intelligence) computer vision and image processing techniques Knowledge engineering techniques image sampling enrolled template adaptation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：