Volume 15, Issue 6

Accurately segmenting and quantifying structures is a key issue in biomedical image analysis. The two conventional methods of image segmentation, region-based segmentation, and boundary finding, often suffer from a variety of limitations. Here the authors propose a method which endeavors to integrate the two approaches in an effort to form a unified approach that is robust to noise and poor initialization. The authors' approach uses Green's theorem to derive the boundary of a homogeneous region-classified area in the image and integrates this with a gray level gradient-based boundary finder. This combines the perceptual notions of edge/shape information with gray level homogeneity. A number of experiments were performed both on synthetic and real medical images of the brain and heart to evaluate the new approach, and it is shown that the integrated method typically performs better when compared to conventional gradient-based deformable boundary finding. Further, this method yields these improvements with little increase in computational overhead, an advantage derived from the application of the Green's theorem.

准确分割和量化结构是生物医学图像分析中的关键问题。传统的图像分割方法，基于区域的分割和边界查找，常常受到各种限制。本文作者提出了一种方法，旨在整合这两种方法，以形成一种对噪声和不良初始化鲁棒的统一方法。作者的方法利用格林定理导出图像中均匀区域分类区域的边界，并将其与基于灰度梯度的边界查找器相结合。这将边缘/形状信息的感知概念与灰度均匀性相结合。在脑部和心脏的合成和真实医学图像上进行了多项实验以评估新方法，结果表明，与传统的基于梯度的可变形边界查找相比，集成方法通常表现更好。此外，该方法在很少增加计算开销的情况下实现了这些改进，这是应用格林定理的一个优势。

Shape-based interpolation as applied to binary images causes the interpolation process to be influenced by the shape of the object. It accomplishes this by first applying a distance transform to the data. This results in the creation of a grey-level data set in which the value at each point represents the minimum distance from that point to the surface of the object. (By convention, points inside ...

应用于二值图像的基于形状的插值使得插值过程受到物体形状的影响。它首先对数据应用距离变换，从而创建一个灰度数据集，其中每个点的值表示该点到物体表面的最小距离。（按照惯例，内部点...）

A good statistical model of speckle formation is useful for designing a good adaptive filter for speckle reduction In ultrasound B-scan images. Previously, statistical models have been used, but they failed to account for the log compression of the echo envelope employed by clinical ultrasound systems. Log-compression helps in reducing the dynamic range of the B-scan Images for display on a monito...

一个良好的散斑形成统计模型对于设计有效的自适应滤波器以降低超声B扫描图像中的散斑噪声非常有用。之前使用的统计模型未能考虑临床超声系统所采用的回波包络的对数压缩。对数压缩有助于减小B扫描图像的动态范围以便在显示器上显示...

This paper examines the problem of obtaining a mathematical representation of the outer cortex of the human brain, which is a key problem in several applications, including morphological analysis of the brain, and spatial normalization and registration of brain images. A parameterization of the outer cortex is first obtained using a deformable surface algorithm which, motivated by the structure of...

本文研究获取人类大脑外层皮层数学表示的问题，这是多个应用中的关键问题，包括大脑形态分析、脑图像的空间归一化和配准。首先使用可变形表面算法获得外层皮层的参数化，该算法受...结构启发。

The authors present a weighted geometrical feature (WGF) registration algorithm. Its efficacy is demonstrated by combining points and a surface. The technique is an extension of Besl and McKay's (1992) iterative closest point (ICP) algorithm. The authors use the WGF algorithm to register X-ray computed tomography (CT) and T2-weighted magnetic resonance (MR) volume head images acquired from eleven ...

作者提出了一种加权几何特征（WGF）配准算法。通过组合点和曲面证明了其有效性。该技术是Besl和McKay（1992）迭代最近点（ICP）算法的扩展。作者使用WGF算法对从十一个...获取的X射线计算机断层扫描（CT）和T2加权磁共振（MR）体积头部图像进行配准。

Presents a model-based phase unwrapping method which represents the unwrapped phase function by a truncated Taylor series and a residual function. An efficient, noniterative computational algorithm is also proposed for calculating the model parameters from the phase derivatives. Sample experimental results are shown to demonstrate the effectiveness of the algorithm for extracting unwrapped phase i...

提出了一种基于模型的相位展开方法，该方法通过截断的泰勒级数和残差函数来表示展开的相位函数。还提出了一种高效的非迭代计算算法，用于从相位导数计算模型参数。示例实验结果表明了该算法在提取展开相位方面的有效性……

This paper presents development and application of a feature extraction method for magnetic resonance imaging (MRI), without explicit calculation of tissue parameters. A three-dimensional (3-D) feature space representation of the data is generated in which normal tissues are clustered around prespecified target positions and abnormalities are clustered elsewhere. This is accomplished by a linear m...

本文介绍了一种用于磁共振成像（MRI）的特征提取方法的开发和应用，无需显式计算组织参数。生成了数据的三维（3-D）特征空间表示，其中正常组织聚集在预设的目标位置周围，异常组织聚集在其他地方。这是通过线性变换实现的...

Conventional two-dimensional (2-D) texture parameters serve as the "gold standard" of texture analysis. The authors compared a new stochastic model, based on autoregressive periodic random field models (APRFM) with conventional texture analysts (CTA) parameter, which were defined as measures of the co-occurrence matrix, i.e., entropy, contrast, correlation, uniformity, and maximum frequency. By fi...

传统的二维（2-D）纹理参数被视为纹理分析的“金标准”。作者将一种基于自回归周期随机场模型（APRFM）的新随机模型与传统的纹理分析（CTA）参数进行了比较，后者定义为共现矩阵的度量，即熵、对比度、相关性、均匀性和最大频率。通过进一步...

In recent years, many image segmentation approaches have been based on Markov random fields (MRFs). The main assumption of the MRF approaches is that the class parameters are known or can be obtained from training data. In this paper the authors propose a novel method that relaxes this assumption and allows for simultaneous parameter estimation and vector image segmentation. The method is based on...

近年来，许多图像分割方法基于马尔可夫随机场（MRF）。MRF方法的主要假设是类别参数已知或可从训练数据中获得。本文作者提出了一种新方法，放宽了这一假设，允许同时进行参数估计和矢量图像分割。该方法基于……

A post-processing technique has been developed to suppress the magnetic resonance imaging (MRI) artifact arising from object planar rigid motion. In two-dimensional Fourier transform (2-DFT) MRI, rotational and translational motions of the target during magnetic resonance magnetic resonance (MR) scan respectively impose nonuniform sampling and a phase error an the collected MRI signal. The artifac...

开发了一种后处理技术，用于抑制由目标平面刚性运动引起的磁共振成像（MRI）伪影。在二维傅里叶变换（2-DFT）MRI中，磁共振扫描期间目标的旋转和平移运动分别导致采集的MRI信号出现非均匀采样和相位误差。该伪影...

In many applications in computer vision and signal processing, it is necessary to assimilate data from multiple sources. This is a particularly important issue in medical imaging, where information on a patient may be available from a number of different modalities. As a result, there has been much recent research interest in this area. The authors suggest an additional Bayesian method which gener...

在计算机视觉和信号处理的许多应用中，需要整合来自多个来源的数据。这在医学影像中是一个尤其重要的问题，因为患者的信息可能来自多种不同的模态。因此，近年来这一领域引起了广泛的研究兴趣。作者提出了一种额外的贝叶斯方法，该方法...

A new method of video compression for angiographic images has been developed to achieve high compression ratio (/spl sim/20:1) while eliminating block artifacts which leads to loss of diagnostic accuracy. This method adopts motion picture experts group's (MPEGs) motion compensated prediction to takes advantage of frame to frame correlation. However, in contrast to MPEG, the error images arising fr...

开发了一种新的血管造影图像视频压缩方法，旨在实现高压缩比（约20:1），同时消除导致诊断准确性损失的分块伪影。该方法采用运动图像专家组（MPEG）的运动补偿预测，以利用帧间相关性。然而，与MPEG不同，由误差图像引起的...

The authors developed a method for mapping the change in cerebral glucose utilization at two different physiological states using [/sup 18/F]fluorodeoxyglucose (FDC) double infection and the constrained weighted-integration method. The authors studied young normal subjects without (baseline-baseline group, n=5) and with (baseline-stimulation group, n=5) vibrotactile stimulation of the fingertips o...

作者开发了一种方法，利用[18F]氟脱氧葡萄糖（FDG）双注射和约束加权积分法，绘制两种不同生理状态下脑葡萄糖利用的变化。作者研究了年轻正常受试者，分为无振动触觉刺激组（基线-基线组，n=5）和有振动触觉刺激组（基线-刺激组，n=5），刺激部位为指尖...