基于混和时频分析方法的ISAR成像研究

采用了一种混合时频算法来克服传统时频算法ISAR成像时交叉项干扰问题,提高成像分辨率;提出了"数据分割-时频分析与采样-数据拼接"成像加速方法提高ISAR成像处理效率.应用强散射回波点目标某飞机模型做仿真实验.对比传统ISAR时频分析方法和本文方法成像表明:本方法成像质量高,关键细节清晰可见,基本消除了无交叉项干扰,时频分辨率高:成像加速算法较传统成像算法缩短了一半以上的成像处理时间,成像实时性得到了显著提升。     

Compressed sampling reconstruction of hyperspectral images based on spectral prediction

With increasing amounts of hyperspectral images (HSI) and the limitations of the memory requirements, compressive techniques for hyperspectral images have attracted extensive research efforts in recent years. The main difficulty of applying compressed sampling (CS) theory to compression and reconstruction of hyperspectral images lies in using the spatial correlation and spectral correlation of hyperspectral images. In this paper, a reconstruction algorithm of hyperspectral images taking advantage of two‐dimensional compressed sampling (2DCS) and two‐dimensional total variation (2DTV) incorporating spectral prediction (SP) is investigated. In the sampling process, the hyperspectral images are divided into reference bands and common bands, and all bands are sampled using 2DCS independently. In the reconstruction process, the reference bands are reconstructed by 2DTV first. In order to improve the reconstruction quality of common bands, spectral prediction utilizing the spectral correlation between reference bands and common bands is conducted. Then the spectral compensation is computed by using a combination of the prediction value and the initial approximation for the common bands. The residual between the compensation value and the original value is obtained to revise the approximation for the common bands. The algorithm is implemented in an iterative manner to enhance the performance. Experimental results on popular hyperspectral datasets reveal that the proposed algorithm exploiting spectral prediction outperforms the algorithm 2DCS‐2DTV, which does not use spectral correlation, as well as the state‐of‐the‐art algorithms in terms of peak signal‐to‐noise ratio (PSNR). In particular, when the sampling rate of the reference bands is higher than that of the common bands, the proposed algorithm would improve the reconstruction quality dramatically. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A novel biorthogonal wavelet network system for off-angle iris recognition

One important category of non-ideal conditions for iris recognition is off-angle iris images. Practically it is very difficult for images to be captured with no offset. It then becomes necessary to account for off angle information in order to maintain robust performance. A biorthogonal wavelet based iris recognition system, previously designed at our lab, is modified and demonstrated to perform off-angle iris recognition. Biorthogonal wavelet network (BWN) are developed and trained for each class. The non-ideal factors are adjusted by repositioning the BWN. To test, along with the real data, synthetic iris images are generated by using affine and geometric transforms of 0°, 10° and 20^° experimentally collected images. The tests were carried out on the experimentally collected off-angle data and synthetically generated data for angles from 0° to 60^° with a resolution of 5^°. This approach is shown to have less constraints than a transformation based iris recognition approach. Iris images off-angle by up to 42^° for synthetic data and up to 45^° for experimental data are successfully recognized.     

Neuropsychological evidence for visual- and motor-based affordance: Effects of reference frame and object–hand congruence.

Two experiments are reported that use patients with visual extinction to examine how visual attention is influenced by action information in images. In Experiment 1 patients saw images of objects that were either correctly or incorrectly colocated for action, with the objects held by hands that were congruent or incongruent with those used premorbidly by the patients. The images were also shown from a 1st- and 3rd-person perspective. There was an overall reduction in extinction for objects colocated for action. In addition, there was an extra benefit when the objects were held in hands congruent with those used by the patients and when the objects were seen from a 1st-person perspective. This last result fits with an effect of motor simulation, over and above a purely visual effect based on positioning objects correctly for action. Experiment 2 showed that effects of hand congruence could emerge with images depicted from a 3rd-person perspective when patients saw themselves holding the objects. The data indicate 2 effects of action information on extinction: (a) an effect of colocating objects for action, which does not depend on a self-reference frame (a visual effect), and (b) an effect sensitive to object–hand congruence, which does depend on a self-reference frame (a motor-based effect). The self-reference frame is induced when stimuli are viewed from a 1st-person perspective and when an image of the self is seen from a 3rd-person perspective. Both visual and motor-based effects of action information facilitate the spread of attention across objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of Booster Sheds to Improve Performance of 800 kV Multicone Type Insulators Under Heavy Rain

Studies based on AC high voltage tests have been done at Cepel to investigate the performance of 800 kV bushar insulators under heavy wetting conditions. Insulators were tested which are now used on si...     

Remote sensing techniques for predicting evapotranspiration from mixed vegetated surfaces

Evapotranspiration (ET) is a key component of the hydrological cycle however it is also the most difficult factor to quantify. In recent decades, estimating ET has been improved by advances in remote sensing, particularly in agricultural studies. However, quantifying ET from mixed vegetation environs, particularly urban parklands, is still challenging due to the heterogeneity of plant species, canopy covers, microclimates, and because of costly methodological requirements. Several studies have recently been conducted in agriculture and forestry which may be useful for mixed landscape vegetation studies with some modifications. This review describes general remote sensing-based approaches to estimate ET and describes their advantages and disadvantages. Most of these approaches need extensive time investment, medium to high skill levels and are quite expensive. However, in addition to the reviewed methods, the authors recommend combining remotely sensed vegetation indices and ground-based techniques for ET estimation of mixed landscape vegetation such as urban parklands.     

Near‐lossless compression methods for spectral images

In this work, several near‐lossless compression methods for spectral images have been analyzed and compared. These methods are based both on the principal component analysis (PCA) and on the choice of a minimum number of spectral points, selected following different criteria. The analysis, initially carried out on 14 National Physical Laboratory tiles of certified colour, has been extended to some spectral images of paintings taken at the National Gallery of Parma (Italy). The comparison of the results with those obtained by applying the PCA analysis shows that the best method indicated as “method of a few significant points” allows reducing the spectral image size of a factor of 10 without loss of spectral and colour information. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010     

Psychological effect of stereoscopic 3-D images with fragrances

Stereoscopic 3-D images are used with a lot of virtual reality systems because of their sense or reality. At the same time, in the training that heightens levels of self control of autonomic responses with images, it is thought that reality of software is important. Therefore, the authors investigated use of 3-D images as a technical tool to heighten the reality of software. In this study, a laboratory was transformed into a relaxation room using 3-D images with fragrances and an experiment was carried out lo examine the psychological effect of it. From the results of this study, the authors reported on the effects of fragrances on psychological responses when viewing 3-D images and the possibilities of producing these effects for relaxation.     

电势公式Φ=q/(4πε_o)(1/r-1/r′)的推广应用研究

根据唯一性定理及镜像法把真空中的电势公式Φ =q4πεo(1r - 1r′)推广到电介质中去 ,使电介质中电势的求解问题得到了进一步简化     

A fully automatic one-scan adaptive zooming algorithm for color images

We present an interpolation algorithm for adaptive color image zooming. The algorithm produces the magnified image in one scan of the input image, and is fully automatic since does not involve any a priori fixed threshold. Given any integer zooming factor n, each pixel of the input image generates an n×n block of pixels in the zoomed image. For the currently visited pixel of the input image, the pixels of its associated block are first assigned tentative values, which are then adaptively updated before building the next block. The method is suggested for RGB images, but can equally be employed in other color spaces. Peak signal to noise ratio (PSNR) and Structural SIMilarity (SSIM) are used to evaluate the performance of the algorithm.