Volume 24, Issue 5

The robust detection of red lesions in digital color fundus photographs is a critical step in the development of automated screening systems for diabetic retinopathy. In this paper, a novel red lesion detection method is presented based on a hybrid approach, combining prior works by Spencer et al. (1996) and Frame et al. (1998) with two important new contributions. The first contribution is a new red lesion candidate detection system based on pixel classification. Using this technique, vasculature and red lesions are separated from the background of the image. After removal of the connected vasculature the remaining objects are considered possible red lesions. Second, an extensive number of new features are added to those proposed by Spencer-Frame. The detected candidate objects are classified using all features and a k-nearest neighbor classifier. An extensive evaluation was performed on a test set composed of images representative of those normally found in a screening set. When determining whether an image contains red lesions the system achieves a sensitivity of 100% at a specificity of 87%. The method is compared with several different automatic systems and is shown to outperform them all. Performance is close to that of a human expert examining the images for the presence of red lesions.

在数字彩色眼底照片中稳健地检测红色病灶是开发糖尿病视网膜病变自动化筛查系统的关键步骤。本文提出了一种基于混合方法的新型红色病灶检测方法，结合了Spencer等人(1996)和Frame等人(1998)的前期工作，并有两项重要的新贡献。第一个贡献是基于像素分类的新的红色病灶候选检测系统。利用该技术，血管和红色病灶从图像背景中分离出来。在移除连接的血管后，剩余的对象被认为是可能的红色病灶。其次，在Spencer-Frame提出的特征基础上增加了大量新特征。使用所有特征和k近邻分类器对检测到的候选对象进行分类。在由筛查集中常见图像组成的测试集上进行了广泛评估。在判断图像是否包含红色病灶时，该系统在特异性为87%的情况下达到了100%的敏感性。该方法与几种不同的自动化系统进行了比较，并显示出优于它们的结果。性能接近于人类专家检查图像中是否存在红色病灶的表现。

Our goal in this paper is the estimation of kinetic model parameters for each voxel corresponding to a dense three-dimensional (3-D) positron emission tomography (PET) image. Typically, the activity images are first reconstructed from PET sinogram frames at each measurement time, and then the kinetic parameters are estimated by fitting a model to the reconstructed time-activity response of each vo...

本文的目标是估计与密集三维正电子发射断层扫描（PET）图像对应的每个体素的动力学模型参数。通常，首先从每个测量时间的PET正弦图帧重建活性图像，然后通过将模型拟合到每个体素的重建时间-活性响应来估计动力学参数...

The paper presents a novel stochastic active contour scheme (STACS) for automatic image segmentation designed to overcome some of the unique challenges in cardiac MR images such as problems with low contrast, papillary muscles, and turbulent blood flow. STACS minimizes an energy functional that combines stochastic region-based and edge-based information with shape priors of the heart and local pro...

本文提出了一种新颖的随机主动轮廓方案(STACS)，用于自动图像分割，旨在克服心脏核磁共振图像中的一些独特挑战，如低对比度、乳头肌和湍流血流问题。STACS通过最小化一个能量泛函，该泛函将基于区域和边缘的随机信息与心脏的形状先验及局部...

Image intensity standardization is a postprocessing method designed for correcting acquisition-to-acquisition signal intensity variations (nonstandardness) inherent in magnetic resonance (MR) images. Inhomogeneity correction is a process used to suppress the low frequency background nonuniformities (inhomogeneities) of the image domain that exist in MR images. Both these procedures have important ...

图像强度标准化是一种后处理方法，旨在校正磁共振（MR）图像中固有的采集间信号强度变化（非标准化）。不均匀性校正是用于抑制MR图像中存在的图像域低频背景不均匀性（不均匀性）的过程。这两个程序都有重要的...

Previously, the noise characteristics obtained with penalized-likelihood reconstruction [or maximum a posteriori (MAP)] have been compared to those obtained with postsmoothed maximum-likelihood (ML) reconstruction, for emission tomography applications requiring uniform resolution. It was found that penalized-likelihood reconstruction was not superior to postsmoothed ML. In this paper, a similar co...

以往，对于需要均匀分辨率的发射断层成像应用，已经将惩罚似然重建（或最大后验概率，MAP）获得的噪声特性与后平滑最大似然（ML）重建获得的噪声特性进行了比较。发现惩罚似然重建并不优于后平滑ML。在本文中，类似...

This paper presents a novel image-guided robot-based system to assist orthopedic surgeons in performing distal locking of long bone intramedullary nails. The system consists of a bone-mounted miniature robot fitted with a drill guide that provides rigid mechanical guidance for hand-held drilling of the distal screws' pilot holes. The robot is automatically positioned so that the drill guide and na...

本文提出了一种新颖的基于图像引导的机器人系统，以协助骨科医生进行长骨髓内钉的远端锁定。该系统由一个安装在骨骼上的微型机器人组成，该机器人配备有钻头导向器，为手持钻头钻取远端螺钉的导向孔提供刚性机械引导。机器人自动定位，使得钻头导向器和...

Image reconstruction in electrical impedance tomography is an ill-posed nonlinear inverse problem. Linearization techniques are widely used and require the repeated solution of a linear forward problem. To account correctly for the presence of electrodes and contact impedances, the so-called complete electrode model is applied. Implementing a standard finite element method for this particular forw...

电阻抗成像中的图像重建是一个病态非线性逆问题。线性化技术被广泛使用，需要重复求解线性正向问题。为了正确考虑电极和接触阻抗的存在，应用了所谓的完整电极模型。对这种特定的正向问题实施标准有限元方法...

A method has been developed that, based on the guide wire position in monoplane fluoroscopic images, visualizes the approximate guide wire position in the three-dimensional (3-D) vasculature, that is obtained prior to the intervention with 3-D rotational X-ray angiography (3DRA). The method assumes the position of the guide wire in the fluoroscopic images is known. A two-dimensional feature image ...

开发了一种方法，该方法基于单平面透视图像中导丝的位置，在三维血管系统中可视化导丝的大致位置，该三维血管系统是在介入前通过三维旋转X射线血管造影（3DRA）获取的。该方法假设导丝在透视图像中的位置已知。二维特征图像...

The recently developed S-transform (ST) combines features of the Fourier and Wavelet transforms; it reveals frequency variation over both space and time. It is a potentially powerful tool that can be applied to medical image processing including texture analysis and noise filtering. However, calculation of the ST is computationally intensive, making conventional implementations too slow for many m...

最近开发的S变换（ST）结合了傅里叶变换和小波变换的特性；它揭示了频率在空间和时间上的变化。这是一个潜在强大的工具，可应用于医学图像处理，包括纹理分析和噪声滤波。然而，ST的计算量很大，使得传统实现对于许多医学应用而言太慢。

Assessing the displacement of bony implants is an important topic in arthroplasty, particularly in total hip replacement (THR). The observation of the migration is supposed to provide an insight into the fixation of the implant. Diagnostic standard radiographs of the pelvis are an advantageous data source for this purpose. The previous methods based on these images, however, lack of a thorough con...

评估骨植入物的移位是关节成形术中的重要课题，特别是在全髋关节置换术（THR）中。观察移位应能提供对植入物固定情况的深入了解。骨盆的诊断标准X光片是此目的的理想数据来源。然而，基于这些图像的以往方法缺乏彻底的...

Previous reports have described the use of magnetic resonance imaging (MRI) to estimate single-kidney extraction fraction (EF) and glomerular filtration rate (GFR), by measuring the concentration difference of intravenously injected Gd-chelate ([Gd]) in the renal artery and renal vein from measurements of blood T1. Problematic is the fact that [Gd] measurements in the renal artery are often inaccu...

先前的研究描述了通过测量血液T1来测定静脉注射钆螯合物([Gd])在肾动脉和肾静脉中的浓度差，从而利用磁共振成像(MRI)估算单肾提取分数(EF)和肾小球滤过率(GFR)。问题在于肾动脉中的[Gd]测量往往不准确...

Statistical tests developed for the analysis of (intrinsically complex valued) functional magnetic resonance time series, are generally applied to the data's magnitude components. However, during the past five years, new tests were developed that incorporate the complex nature of fMRI data. In particular, a generalized likelihood ratio test (GLRT) was proposed based on a constant phase model. In t...

为分析（固有复值）功能磁共振时间序列而开发的统计检验通常应用于数据的幅度分量。然而，在过去五年中，开发了结合fMRI数据复性质的新检验。特别地，基于恒定相位模型提出了广义似然比检验（GLRT）。在...

Provides a listing of current staff, committee members and society officers.

提供当前工作人员、委员会成员和社会官员的列表。

Presents the table of contents for this issue of the periodical.

提供本期期刊的目录。

Provides notice of upcoming special issue(s) of interest to practitioners and researchers.

为从业者和研究人员提供即将出版的专刊通知。

Provides notice of upcoming conference events of interest to practitioners and researchers.

提供与会者和研究人员感兴趣的即将召开的会议活动通知。

Describes the above-named upcoming conference event. May include topics to be covered or calls for papers.

描述上述即将举行的会议活动。可能包括涵盖的主题或征稿通知。

Provides instructions and guidelines to prospective authors who wish to submit manuscripts.

为有意提交稿件的研究人员提供指南和要求。