Edge Detection in Digital Images Using Guided L0 Smoothen Filter and Fuzzy Logic

Image segmentation is an important process in computer vision. Recently fuzzy logic based edge detection is heavily investigated as by changing the number of rules edge detection can be improved. However, due to large colour variations in the images false edges are detected and even using fuzzy rules they cannot be reduced significantly. These falsely detected edges can be controlled by using smoothen filter while controlling the degree of smoothness. This paper, presents fuzzy logic based edge detection mechanism while using Guided L₀ smoothen filter for the smoothening of image under various degree of smoothens. Simulation results for edge detection is presented for Canny, Sobel, Fuzzy logic based edge detection and finally fuzzy logic edge detection with inclusion of L₀ smoothen filter. The results are compared with classical and modern methods. Simulation is performed on Berkley Segmentation Database (BSD) and USC-SIPI Image Database while considering more than 100 images. The obtained F-measure is as high as 0.848.

     

Adaptation of CDMA Soft Handoff Thresholds Using Fuzzy Inference System

This paper proposes a new procedure to adjust soft handoff thresholds dynamically by using fuzzy inference system. This algorithm is compared with IS-95A and IS-95B/cdma2000 soft handoffs. The aims are to increase the thresholds at high traffic loads in order to release the traffic channel for supporting more carried traffic, and to decrease the thresholds at low traffic loads in order to give high quality of traffic channel. The inputs of the proposed algorithm are the number of remaining channels of each base station and the number of active pilots in active set of each mobile station. The output is the new soft handoff thresholds. In the fuzzy inference module, the triangular membership function, the max-min composition, and the weighted average formula defuzzification are selected. By comparison of all performance indicators among three algorithms, soft handoff using fuzzy inference tends to give higher performance than those of IS-95A and IS-95B/cdma2000 soft handoffs at high traffic loads and at lower soft handoff thresholds while the quality of traffic channel is still acceptable. Moreover, the wider soft handoff window size of the proposed algorithm gives high carried traffic and low blocking probability but lower quality of traffic channels. In addition, the adaptive soft handoff window size can give lower blocking probability while still keep acceptable quality of traffic channels.     

Registration of Brain Atlas to MR Images Using Topology Preserving Front Propagation

Registration of brain atlases to MR images is important in both anatomic and functional studies of human brains. Existing intensity-based methods are confronted with the translation of image-similarity functions to desired anatomic correspondences; while feature-based methods are challenged with the automated extraction of required features. In this paper, we propose a non-rigid registration method, in which, a block matching method is first used to calculate boundary displacement of all structures in a brain atlas, and a topology preserving front propagation method is then used to deform the atlas by warping the structures according to their boundary displacements. The novelty of our method is that the registration procedure is automated and anatomically driven while there is no need to extract particular structures. Experiments on the registration of the Talairach–Tournoux brain atlas to phantom brain MR images and real data show that our method is robust to noise and intensity inhomogeneity, more accurate than the commonly used Talairach stereotaxic spatial normalization, and thus promising to open new applications for brain atlases.     

基于边缘特征的异质图像目标配准方法

目标检测作为计算机视觉的重要研究课题,在视频监控和智能导航方面有重要应用.图像配准技术是刚体目标检测方法之一.异质图像间目标的纹理差异极大,为此,对于目标的可见光俯视图像与机载红外摄像机观测异质图像,通过研究基于边缘特征的配准技术,实现对地面平面目标的配准检测.笔者首先通过建立机载运动摄像机空间模型,解决了红外观测图像的视角变换问题,将其换到与参考图像一致的视角,提出一种新颖的基于稳定区域轮廓合成的边缘提取方法,更好地控制异质图像的边缘提取效果,边缘特征匹配是在距离变换的基础上实现的,提出了一种基于稳定区域距离图像互相关的匹配度量准则.实验表明,算法能有效地实现异质图像间的目标配准检测.     

Prolog模糊推理机

本文采用基于模糊集会论的推理策略，为TurboProlog设计了一个模糊推理机外壳，使其能够在保持原有系统功能的基础上处理模糊信息。     

自适应边缘保持图像缩放及VLSI设计

提出的自适应边缘保持图像缩放方法,以自适应的方式对传统的线性插值方法非线性修正,使得不同位置的像素采用相应的插值方法.边缘保持插值算法能消除图像边缘模糊,锯齿效应,棋盘效应等,达到增强插值图像的效果.本算法处理后的放大图像的边缘更加锐利,能够实现图像的无级放大,可应用于实际的数字视频处理芯片中.     

Restoring Spline Interpolation of CT Images

In this paper a new technique is used to interpolate the sampled CT image data in the axial direction for a coronal display. This technique also compensates the high spatial frequency components in that direction to get a narrower point-spread function. Computer simulation results are presented here to show the effect of aperture convolution and the effect of spatial sampling in a practical imaging system. It is illuminating to describe the procedures of interpolation in terms of digital filtering. The advantage of restoring spline interpolation is due to the extra frequency compensation in the matrix inversion step. Both step function and sinusoidal function are used in the simulation. The enhanced transition edge and the smaller absolute error in the restoring spline interpolated results are shown. The absolute error depends to a certain extent on the sampling interval relative to the Nyquist interval which is also discussed. There is a small amount of amplification of existing noise or generation of new noise in this technique. Some initial results on a CT image using this technique are also presented.     

Adaptive Least Squares Interpolation of Infrared Images

This paper presents an adaptive block-by-block least squares (LS) algorithm for the interpolation of infrared (IR) images. The suggested algorithm is based on the segmentation of the low resolution (LR) image into overlapping blocks and the interpolation of each block, separately. The purpose of the overlapping is to avoid edge effects between blocks. An iterative implementation of the proposed algorithm, which considers the image acquisition model, is used for the minimization of the estimation error in each block. A weight matrix of moderate dimensions is estimated in a small number of iterations to interpolate each block. This proposed algorithm avoids the large computational complexity resulting from the matrices of large dimensions required to interpolate the image as a whole. The performance of the proposed algorithm is compared with the standard as well as the warped distance optimal interpolation of maximal order with minimal support (O-MOMS) algorithm from the peak signal-to-noise ratio (PSNR) point of view. Numerical results reveal the superiority of the proposed LS algorithm to the cubic O-MOMS algorithm.     

Edge Preserving Lossy Image Compression with Wavelets and Contourlets

In this paper an edge preserving lossy image coder is presented. An edge image is obtained from the original with a digital image processing module using four different filters: Canny, Sobel, Roberts and Prewitt, then the original image is domain transformed with wavelets or contourlets, and a pixel mapping from original domain to transformed is done. For the compression, the edges points and the approximation image (which determines the compression factor) are selected; finally the image is decompressed in order to observe the reconstruction quality and edge preserving. The stages of the compression system are: a) Image selection, b) Digital image processing, c) Feature vector extraction, d) Domain Transformation, e) Pixel mapping, f) Image compression and g) Image decompression. Additionally, the results obtained from comparisons of error measures between original and decompressed images are shown and finally conclusions about the coder are presented.     

一种用于数字音频的插值滤波器设计

设计了一种应用于数字音频的插值滤波器。该滤波器采用多相插值原理,硬件电路包括并行数据输入接口、8倍插值器、16倍采样保持电路,实现对输入音频信号(PCM码)的128倍过采样。滤波器电路由VerilogHDL语言实现,利用SYNOPSYS提供的EDA工具进行仿真、综合,并通过FPGA验证,结果表明该电路能满足性能要求。     

A QoS Aware Dynamic Scheduling Scheme Using Fuzzy Inference System for IEEE 802.16 Networks

Providing quality of service (QoS) for diverse multimedia services is an important issue in IEEE 802.16 (WiMAX) networks. A scheduling mechanism that satisfies the QoS requirements has become more important for multimedia networks. In addition, scheduling algorithms for wireless networks are much more complex than that of wired networks because of channel quality variations and radio resource limits. This paper introduces a QoS Aware Scheduling System, based on fuzzy logic, for traffic management in WiMAX point-to-multi-point (PMP) networks. The proposed method attempts to guarantee delay and throughput QoS criteria. It considers QoS criteria and radio quality of each user in decision making processes. A series of simulation experiments have been carried out to evaluate the performance of the proposed scheduling system. The results show that the proposed method performs effectively to achieve QoS criteria and attains significant system performance for different types of traffic.     

全方向M型心动图像边界平滑的研究

主要针对全方向M型心动图边界进行平滑处理，全方向M型心动图是利用B超获取的心脏各结构的序列图像，沿各个方向提取的心脏某结构部位灰度点位置变化在时间轴上展开得到的运动轨迹，其边缘线即全方向M型心动图边界代表了该灰度点的运动方程。依据其特点及要求，采用了线状平滑模板，通过时不同平滑滤波方法进行分析比较，提出了自适应模板保形平滑滤波，973非线性模板平滑滤波，实现了消除噪声干扰及减弱阶梯效应的影响的目的。从而保证了时全方向M型心动图的动态信息进行进一步分析的可靠性。     

Demosaicing of Color Filter Array Captured Images Using Gradient Edge Detection Masks and Adaptive Heterogeneity-Projection

Without demosaicing processing, this paper first proposes a new approach to extract more accurate gradient/edge information on mosaic images directly. Next, based on spectral-spatial correlation, a novel adaptive heterogeneity-projection with proper mask size for each pixel is presented. Combining the extracted gradient/edge information and the adaptive heterogeneity-projection values, a new edge-sensing demosaicing algorithm is presented. Based on 24 popular testing images, experimental results demonstrated that our proposed high-quality demosaicing algorithm has the best image quality performance when compared with several recently published algorithms.      

数字图像处理的内插方法

介绍数字图像处理中各种行、场内插的方法,并从算法、处理效果和硬件实现等方面分析各种方法的优缺点.     

Speech Interpolation in Digital Transmission Systems

In a telephone conversation a channel is activated by the voice only 25 percent of the time. It is therefore possible to provide a number ofmconnections with a number ofnchannels, wherenis less thanm. When the number of connections is large,m/n(gain) tends to the inverse of the activity. The interpolation procedures used in overload conditions and the resulting degradations, as well as the typical circuits of a voice interpolation apparatus, are examined. Also, two very highly interesting developments are herein illustrated, the ATIC equipment and a single-channel digital speech interpolation (DSI) developed only for measurement purposes. The results obtained from measurement studies carried out with the aforementioned apparatus have enabled the determination of the criteria which must be followed in the selection of the most suitable interpolation procedures. Besides examining the complexity and the reliability which the DSI equipment calls for, it has been possible to analyze the precise working characteristics under normal operating conditions.     

Wavelet-based Interpolation Scheme for Resolution Enhancement of Medical Images

A novel interpolation method for resolution enhancement is proposed in this paper. This method estimates wavelet coefficients in the high frequency subbands from a low resolution image using our proposed filters. An inverse wavelet transform is then performed for synthesis of a higher resolution image. Experimental results show that our proposed method outperforms other commonly used schemes objectively and subjectively. In addition, the processing time required in an algorithm-implemented Digital Signal Processor (DSP) is satisfied. By using the DSP hardware platform, off-line interpolation processing becomes easier and more feasible. The interpolated image has merits of high contrast and remarkable sharpness which essentially meet the requirements for interpolation of medical images. Our method can provide better quality of interpolated medical images compared to other methods to assist physicians in making diagnoses.     

Measurement of Torsion from Multitemporal Images of the Eye Using Digital Signal Processing Techniques

Two methods of measuring ocular torsion from digital images of the eyes were developed and tested. One method measures torsion from the translation of two landmarks using a rectilinear coordinate system. The second method measures torsion from the translation of two landmarks using a polar coordinate system. The center for the polar sampling is the center of the pupil. After thresholding and filtering the images, landmark translation is measured from the interpolated peak in the normalized cross correlation of the reference landmark with the image.     

一种改进的SAR图像边缘检测算法

灰度平均值比率与梯度(RGoA)边缘检测器是一种简单、有效的SAR图像边缘检测方法.但它也存在缺点,边缘点检测准则在某些情况下不适用,比率门限和梯度门限均需要由人工预先确定.本文提出一种改进的SAR图像边缘检测算法,它修正了边缘点检测准则,采用Otsu方法计算灰度平均值比率门限和梯度门限,实现优化门限自动选择.用SAR图像对算法进行了实验验证.实验结果表明,所提出的算法是一种有效、实用、自动的边缘检测算法.     

Reproducible Classification of Infarct Heterogeneity Using Fuzzy Clustering on Multicontrast Delayed Enhancement Magnetic Resonance Images

Delayed enhancement MRI (DE-MRI) can be used to identify myocardial infarct (MI). Classification of MI into the infarct core and heterogeneous periphery (called the gray zone) on conventional inversion-recovery gradient echo (IR-GRE) DE-MRI images has been related to inducibility for ventricular tachycardia. However, this classification is sensitive to image noise, depends on the signal intensity characteristics in a remote region of myocardium, and requires manual contours of the endocardial border. Image analysis and fuzzy clustering techniques were developed to analyze images acquired using a multicontrast delayed enhancement (MCDE) sequence in order characterize the infarct zones. The MCDE analysis is automated and uses data fitting of signal intensities acquired at multiple inversion times. In a study of 15 patients with chronic MI, the gray zones derived from IR-GRE and MCDE images were comparable. The variability in the gray zone size associated with random noise and operator input was significantly reduced using the MCDE-based analysis compared to the IR-GRE-based analysis. In summary, the MCDE approach yields a more reproducible measure of the infarct core and gray zones on any given data set.