oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
直接蒸发式冰蓄冷空调的蓄冰槽融冰强化换热  [PDF]
肖睿,何世辉,杜艳利,黄冲,冯自平,国德防,崔昌学,杜光林
工程热物理学报 , 2008,
Abstract: 现有的直接蒸发式冰蓄冷空调蓄冰槽内在融冰运行时都存在不利于传热的较大垂直温差。本文通过在蓄冰槽中下部位置处设置水平交叉盘管,使蓄冰槽内的竖直冰柱易于断裂,从而改善槽内自然对流条件,达到强化换热的目的。实验表明,水平盘管的布置明显减小了蓄冰槽内在融冰过程中的上下层温差,传热过程得到强化,融冰速度加快,制冷系统的COP也相应得到提高
严寒地区隧道围岩冻融状况分析的导热与对流换热模型  [PDF]
何春雄,吴紫汪,朱林楠
中国科学 地球科学 中国科学 地球科学 , 1999,
Abstract: ?通过对严寒地区隧道现场基本气象条件的分析,建立了隧道内空气与围岩对流换热及固体导热的综合模型;用此模型对大兴安岭西罗奇2号隧道的洞内气温分布进行了模拟计算,结果与实测值基本一致;分析预报了正在开凿的祁连山区大坂山隧道开通运营后洞内温度及围岩冻结、融化状况.
Multifocus Image Fusion Combined Multiwavelet with Contourlet
Yuelin Zou,You Guo,Liang Tian
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: In this study, we propose a new image fusion method by combining Multiwavelet with Contourlet transform. Firstly, transform the source multifocus images successively by Multiwavelet and Conotourlet. Secondly, we employ the LEM rule to fuse the lowpass coefficients and PCCN rule to fuse the hightpass coefficients. Finally, inversely transform the fused coefficients successively by Contourlet and Multiwavelet. This algorithm is obviously better than Multiwavelet or Contourlet method in the fusion effect and the objective criterion of MI and QAB/F.
Palmprint recognition using Contourlet Transform Energy Features  [PDF]
M.A Leo Vijilious,V.Subbiah Bharathi
Indian Journal of Computer Science and Engineering , 2011,
Abstract: Palmprint recognition is an accepted and widely used biometric. Richness of feature and the less cost involved in acquisition make it more reliable and user friendly. The region of interest is extractedfrom the palmprint image as a preprocessing step. Contourlet transform, a pyramidal directional filter bank is then applied to capture both local and global details of the palmprint. The large number of coefficients generated from the contourlet transform are minimised as a dimensionality reduction process, by calculating energies for each subband. Palmprint matching is then performed using nearest neighbor classifier.
Contourlet Transform Based Watermarking for Colour Images
Dinesh Kumar,Vijay Kumar
International Journal of Multimedia & Its Applications , 2011,
Abstract: This paper presents a contourlet transform based watermarking scheme for colour images. It also makes use of discrete cosine transform and singular value decomposition. Discrete cosine transform is appliedon three colour components (Y, Cb and Cr), obtained from the colour image, to produce DCT coefficients. These coefficients are decomposed into directional subbands using 2- level contourlet transform. The watermark is also decomposed using contourlet transform. The fourth directional subbands of cover image and watermark as well are further subjected to Laplacian pyramid decomposition. As a result, the low pass subbands are obtained. The singular values of lowpass subbandof watermark are embedded into singular values of lowpass subband of cover image. The experimental results reveal that the proposed watermarking scheme is robust against common image processingattacks. The results also demonstrate good imperceptibility.
Image Denoising Algorithm Based on Dyadic Contourlet Transform  [cached]
Hui Fan,Yongliang Wang,Jinjiang Li
Journal of Software , 2011, DOI: 10.4304/jsw.6.6.1117-1124
Abstract: This paper constructs a dyadic non-subsampled Contourlet transform for denoising on the image. The transformation has more directional subband, using the non-subsampled filter group for decompositing of direction, so it has the translation invariance, eliminated image distortion from Contourlet transform’s lack of translation invariance. Non-subsampled filter reduces noise interference and data redundancy. Using the feature of NSCT translation invariance, multiresolution, multi-direction, and can according to the energy of NSCT in all directions and in all scale, adaptive denoising threshold. Experimental results show that compared to wavelet denoising and traditional Contourlet denoising, the method achieves a higher PSNR value, while preserving image edge details, can effectively reduce the Gibbs distortion, improve visual images.
ContSteg: Contourlet-Based Steganography Method  [PDF]
Hedieh SAJEDI, Mansour JAMZAD
Wireless Sensor Network (WSN) , 2009, DOI: 10.4236/wsn.2009.13022
Abstract: A category of techniques for secret data communication called steganography hides data in multimedia me-diums. It involves embedding secret data into a cover-medium by means of small perceptible and statistical degradation. In this paper, a new adaptive steganography method based on contourlet transform is presented that provides large embedding capacity. We called the proposed method ContSteg. In contourlet decomposi-tion of an image, edges are represented by the coefficients with large magnitudes. In ContSteg, these coeffi-cients are considered for data embedding because human eyes are less sensitive in edgy and non-smooth re-gions of images. For embedding the secret data, contourlet subbands are divided into 4×4 blocks. Each bit of secret data is hidden by exchanging the value of two coefficients in a block of contourlet coefficients. Ac-cording to the experimental results, the proposed method is capable of providing a larger embedding capacity without causing noticeable distortions of stego-images in comparison with a similar wavelet-based steg-anography approach. The result of examining the proposed method with two of the most powerful steganaly-sis algorithms show that we could successfully embed data in cover-images with the average embedding ca-pacity of 0.05 bits per pixel.
Improved Efficiancy of CBIR using Contourlet Transform
T. Naga Kartheeka,M. Koteswara Rao,K.Veeraswaamy
International Journal of Advanced Electrical and Electronics Engineering , 2012,
Abstract: Content-based image retrieval (CBIR) is an impotent research area for manipulating large amount of image database and archives. In this paper we explain the efficiency retrieval rate of content based image retrieval system using contourlet transform. the multiresolution using the Laplacian pyramid (LP).And the directionality can be analyzed by using the Directional Filter bank(DFB) .In CBIR system using Contourlet Transform based features directionality and anisotropy are made it powerful. Improved results in terms of retrieval efficiency and less complexity are observed in recent work .The distance measures VIZ., Manhattan distance and minkowaski distance are used in similarity measures in the proposed CBIR system
Image Enhancement Based on the Contourlet Transform and Mathematical Morphology
基于Contourlet变换和形态学的图像增强方法

XIANG Jing-bo,SU Xiu-qin,LU Tao,
向静波
,苏秀琴,陆陶

光子学报 , 2009,
Abstract: Traditional methods for image enhancement cannot capture the geometric information of images and tend to amplify noise. To overcome the above enhancement issues, a new enhancement algorithm for image was proposed based on the Contourlet transform and mathematical morphology. The new algorithm decomposed image into approximation-coefficients and detail coefficients. Morphological dilation operations was used to distinguish noise form detail information according to dependencies of contourlet coefficients, then nonlinear mapping function was used to modify the contourlet coefficients. And the enhanced image were obtained by contourlet inverse transform. The experiments show that utilizing the proposed algorithm can enhances image detail and the signal to noise ratio.
Novel Algorithm of Multi-sensor Image Fusion Using Contourlet
基于Contourlet的图像融合新方法

MIAO Qi-guang,WANG Bao-shu,
苗启广
,王宝树

计算机科学 , 2008,
Abstract: The problem of contour segment of 2-dimensional image could not be gotten very well with wavelet transform in image processing is analyzed in this paper.The linear and curve singularity could not be expressed by wavelet trans- form.Then,the principal of Contourlet and its good performance in expressing the singularity of 2-dimensional or high dimensional are studied.The feasibility of image fusion using contourlet transform is discussed in detail.A new fusion method based on Contourlet transform and the fus...
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.