基于Z型结构的低存储二维DWT硬件结构

为了适应当前高清多灰度值显示和片上低存储需求,提出了一种高效低存储DWT的VLSI结构.采用了行列并行运行结构,并且行列运算均使用流水线机制,提高了硬件的利用率.并且使用各16位来存储小波系数的整数(包括符号位)部分和小数部分,使得这种结构能支持1023级(10位)灰度值和较高精度的需求.经过RTL级仿真和SMIC的0.18um工艺综合,结果表明,这种设计可在100MHZ时钟下,采用9/7滤波器经过5级分解,每秒可处理约65帧1024*1024* 10位的图像.     

Cloud top temperature based precipitation intensity estimation using INSAT-1D data

Precipitation intensity associated with each cloud type is an important parameter as it suggests the respective contribution of different categories of clouds to rainfall. The present paper aims at demonstrating a technique of establishing a relationship between the various sub-zero Celsius temperature ranges of clouds with cold top temperatures and their precipitation intensities. Indian Satellite (INSAT-1D) infrared and visible band data were utilized for this purpose. A regression analysis was performed and various cases statistically analysed. The results indicated that nearly all clouds with their tops colder than 275K contribute to precipitation. On combining the results of precipitation intensity with cloud type, it has been found that during the monsoon season the contribution of different clouds to rainfall over an area decreases in the study area: the maximum being from cumulonimbus (1.75-1.49 mm h^-1), followed by nimbostratus (0.97- 0.86 mm h^-1) and altocumulus/altostratus (0.97-0.86 mm h^-1). The contributions from other cloud types, such as status, cumulus or stratocumulus, is insignificant for this study region during the period under observation. However, the precipitation estimates for other clouds like cirrus, cirrostratus and cirrocumulus are unpredictable from the scheme presented here due to several inherent limitations. The image processing technique of level slicing was also utilized to yield fast and reliable images depicting the regions of varying rainfall. Although the analysis has some limitations, it clearly illustrates the relationship between the cloud top temperature and precipitation intensities which may be utilized in actual practice.     

Sparse recovery based reversible data hiding method using the human visual system

In this paper, a novel sparse recovery based reversible data hiding (RDH) method using the human visual system (HVS) is presented. To improve the low accuracy of existing predictors, a sparse recovery based predictor is proposed. In the processes of sparse recovery, the most relevant neighbors can be adaptively chosen by using sparse representation to predict the current pixel accurately, and thus the concentrated prediction error histogram (PEH) is built to obtain good embedding performance. Moreover, to overcome the conflict between the embedding order of the traditional RDH method and the evaluation of HVS, a new embedding strategy based on just noticeable difference (JND) is designed. In this strategy, pixels are classified into sensitive and in-sensitive clusters according to JND values, and two corresponding PEHs are built. Accordingly, different inner regions of two PEHs are adjusted to meet the required embedding capacity, and the prediction error expansion (PEE) technique is utilized to embed data. Experimental results prove that the proposed method outperforms the state-of-the-art RDH methods, including JND related methods.     

Robust audio watermarking algorithm based on DWT using Fibonacci numbers

Multimedia Tools and Applications - This paper presents a blind and robust audio watermarking algorithm developed based on Fibonacci numbers properties and the discrete wavelet transform (DWT)...     

Chaos based cryptosystem for still visual data

Recent years have witnessed a strong relationship between chaos and cryptography. Owing to this relationship, development in one field directly impacts the other field. High computational resources are consumed in re-designing of the complete cryptosystem due to a newly developed chaotic map. Also, the tools developed to discern chaos leads to easy cryptanalysis of chaotic cryptosystems. To save resources and overcome easy cryptanalysis, this paper proposes a spatial domain based chaotic cryptosystem that employs different chaotic maps during permutation-substitution process. Multiple iterations have been performed to achieve resistance against various cryptanalytic and error function attacks, that are specifically designed for chaos based cryptosystems. The proposed technique has been generalized and verified for different chaotic maps. A significant benefit of the proposed cryptosystem is its support for chaotic system free property, which allows replacement of an existing chaotic map with a different map at a later stage. Thorough performance, security and comparative analysis ascertains efficacy of the proposed technique.     

Fragile high capacity data hiding in digital images using integer-to-integer DWT and lattice vector quantization

Multimedia Tools and Applications - Data hiding in digital multimedia has been extensively used for sensitive data transmission and data authentication. An important property of data hiding which...     

一个基于OLAM的可视化数据挖掘系统原型

基于OLAM的可视化数据挖掘系统将可视化工具和数据挖掘工具融为一体,它与一般的数据挖掘系统不同,充分利用了OLAM模型沿着多个维进行挖掘,并以智能的方式与用户进行交互,可以在多维数据库的不同部位和不同的抽象级别交互地执行挖掘,以图形的方式输出结果。     

Tree species differentiation using intensity data derived from leaf-on and leaf-off airborne laser scanner data

Tree species identification is important for a variety of natural resource management and monitoring activities including riparian buffer characterization, wildfire risk assessment, biodiversity monitoring, and wildlife habitat assessment. Intensity data recorded for each laser point in a LIDAR system is related to the spectral reflectance of the target material and thus may be useful for differentiating materials and ultimately tree species. The aim of this study is to test if LIDAR intensity data can be used to differentiate tree species. Leaf-off and leaf-on LIDAR data were obtained in the Washington Park Arboretum, Seattle, Washington, USA. Field work was conducted to measure tree locations, tree species and heights, crown base heights, and crown diameters of individual trees for eight broadleaved species and seven coniferous species. LIDAR points from individual trees were identified using the field-measured tree location. Points from adjacent trees within a crown were excluded using a procedure to separate crown overlap. Mean intensity values of laser returns within individual tree crowns were compared between species. We found that the intensity values for different species were related not only to reflective properties of the vegetation, but also to a presence or absence of foliage and the arrangement of foliage and branches within individual tree crowns. The classification results for broadleaved and coniferous species using linear discriminant function with a cross validation suggests that the classification rate was higher using leaf-off data (83.4%) than using leaf-on data (73.1%), with highest (90.6%) when combining these two LIDAR data sets. The result also indicates that different ranges of intensity values between two LIDAR datasets didn't affect the result of discriminant functions. Overall results indicate that some species and species groups can be differentiated using LIDAR intensity data and implies the potential of combining two LIDAR datasets for one study.     

A fuzzy based ROI selection for encryption and watermarking in medical image using DWT and SVD

Nowadays secure medical image watermarking had become a stringent task in telemedicine. This paper presents a novel medical image watermarking method by fuzzy based Region of Interest (ROI) selection and wavelet transformation approach to embed encrypted watermark. First, the source image will undergo fuzzification to determine the critical points through central and final intensity along the radial line for selecting region of interest (ROI). Second, watermark image is altered to time-frequency domain through wavelet decomposition where the sub-bands are swapped based on the magnitude value obtained through logistic mapping. In the each sub-band all the pixels get swapped, results in fully encrypted image which guarantees the watermark to a secure, reliable and an unbreakable form. In order to provide more robustness to watermark image, singular values are obtained for encrypted watermark image and key component is calculated for avoiding false positive error. Singular values of the source and watermark image are modified through key component. Experimental results reveal that the proposed algorithm attains high robustness and improved security to the watermarked image against various kinds of attacks.

     

基于观测数据偏差修正的DBSCAN改进算法

在经典DBSCAN聚类算法中距离度量直接影响到聚类的结果,为了使观测数据的偏差不影响到距离度量,在研究观测数据预处理过程及经典DBSCAN聚类算法基础上,提出了一种DBSCAN距离度量的改进算法,指出了观测数据偏差修正的基本思想及改进算法的处理流程.仿真结果表明,改进算法能很好地修正观测数据的偏差,最终得到较好的聚类结果.     

基于串行数据存储的腐蚀检测仪

文章介绍的是一套腐蚀检测仪系统,系统通过51单片机对A/D芯片进行控制,完成从模拟量到数字量的转换,并通过串行数据存储器对采集到的数据进行存储。系统实现了对一段时间内微电流的监测,具有电路简单、数据携带方便、成本低等优点。文中着重对系统中如何将采集到的数据进行存储做了介绍。     

Classifying individual tree genera using stepwise cluster analysis based on height and intensity metrics derived from airborne laser scanner data

This paper evaluates the ability of small footprint, multiple return and pulsed airborne scanner data to classify tree genera hierarchically using stepwise cluster analysis. Leaf-on and leaf-off airborne scanner datasets obtained in the Washington Park Arboretum, Seattle, Washington, USA were used for tree genera classification. Parameters derived from structure and intensity data from the leaf-on and leaf-off laser scanning datasets were compared to ground truth data. Relative height percentiles and simple crown shapes using the ratio of a crown length to width were computed for the structure variables. Selected structure variables from the leaf-on dataset had higher classification rate (74.9%) than those from the leaf-off dataset (50.2%) for distinguishing deciduous from coniferous genera using linear discriminant functions.Unsupervised stepwise cluster analysis was conducted to find groupings of similar genera at consecutive steps using k-medoid algorithm. The three stepwise cluster analyses using different seasonal laser scanning datasets resulted in different outcomes, which imply that genera might be grouped differently depending on the timing of the data collection. When combining leaf-on and leaf-off LIDAR datasets, the cluster analysis could separate the deciduous genera from evergreen coniferous genera and could make further separations between evergreen coniferous genera. When using the leaf-on LIDAR dataset only, the cluster analysis did not separate deciduous from evergreen genera. The overall results indicate the importance of the timing of laser scanner data acquisition for tree genera separation and suggest that the potential of combining two LIDAR datasets for improved classification.     

基于DCT和DWT域的音频信息隐藏算法

提出了一种基于DCT域和DWT域的音频信息隐藏算法.该算法充分利用了离散小波变换的多分辨率特性和离散余弦变换的能量压缩能力,通过量化的方法把保密语音信息隐藏到原始的载体音频中,在保密语音的提取过程中不需要原始音频信号的参与.仿真试验表明,该算法的鲁棒性和不可感知性比单独采用DCT变换或DWT变换更好.     

基于DWT和ONMF的人脸表情特征提取

提出了一种基于离散小波变换(discrete wavelet transformation,DWT)和标准正交非负矩阵分解(orthonormal non-negative matrix factorization,ONMF)的人脸表情特征提取方法,该方法先通过离散小波变换,降低图像的噪声,并将得到的图像的低频信息作为研究对象;再采用标准正交非负矩阵分解来提取表情特征.实验结果表明相对于PCA,NMF和LNMF方法,本文方法能够有效地减小类内与类间距离的比值,体现了很好的聚类效果;较高的识别率和较快的识别速度表明了该特征提取方法的有效性.     

基于DWT和SVD联合的数字水印算法

离散小波变换(DWT)和奇异值分解都可以作为数字水印算法有效的工具.提出了一种基于离散小波变换和奇异值分解联合的数字水印算法,先将整个图像分成4个区域,然后再对每个区域运用奇异值分解方法,通过修改奇异值来嵌入水印信息.实验结果表明,该算法具有很好的稳健性,在经过了一般的信号处理操作和JPEG压缩后,嵌入的水印能被可靠的提取和检测.     

Novel robust image watermarking based on subsampling and DWT

This paper presents a robust digital image watermarking scheme based on subsampling and DWT. Subsampling is firstly used to construct a subimage sequence as a video segment. Then, a random watermark sequence satisfied with Gaussian distribution is block-wised embedded into the DWT domain of these subimages repeatedly using the video watermarking technique. And watermark is detected through computing correlation between watermark and watermarked frames. The experiment results demonstrate that the proposed scheme achieves good robustness against JPEG compression, common image processing operation and geometric distortions. Furthermore, the proposed watermarking scheme is also robust against linear collusion and other video watermarking attacks.     

Business-oriented software process improvement based on CMMI using QFD

Software Process Improvement (SPI) has become the key to the survival of many software development organizations. As a follow-up of a previous paper on SPI for the CMM using Quality Function Deployment (QFD), a new SPI framework integrating QFD with the CMMI is developed. Similar to the earlier SPI framework for the CMM, the proposed SPI framework based on the CMMI using QFD aims to achieve three objectives: (1) to map process requirements, including business requirements, to the CMMI with the help of QFD; (2) to develop a method based on QFD for the integration and prioritization of requirements from multiple perspectives (groups); and (3) to be able to prioritize software process improvement actions based on process requirements.Process requirements from multiples groups of stakeholders (perspectives), including business goals, are integrated and prioritized. SPI actions are linked to these process requirements using QFD. Thus, the priorities of actions reflect the priorities of process requirements. By executing the actions with the highest priorities, the highest satisfaction level of process requirements can be achieved. One unique feature of the framework for the CMMI Continuous representation is that the priority values of these actions can be compared across PAs, even when the PAs attempt to reach different capability levels.     

Content-based medical image retrieval using a novel hybrid scattering coefficients - bag of visual words - DWT relevance fusion

Multimedia Tools and Applications - Image content analysis plays a major role in image classification, retrieval, and indexing together with object and scene recognition. Numerous image content...     

On combining range and intensity data

This paper addresses the problem of combining range and intensity data for scene analysis. Although both sources of information describe the same scene, they are very dissimilar. To place both sources of information in the same form, the edge maps of the range image and of the intensity image are derived. An initial step in examining the edge maps is to observe which edges they have in common. Two procedures for extracting the edges common to the range image and the intensity image are presented.