Volume 25, Issue 11

Measures of overlap of labelled regions of images, such as the Dice and Tanimoto coefficients, have been extensively used to evaluate image registration and segmentation algorithms. Modern studies can include multiple labels defined on multiple images yet most evaluation schemes report one overlap per labelled region, simply averaged over multiple images. In this paper, common overlap measures are generalized to measure the total overlap of ensembles of labels defined on multiple test images and account for fractional labels using fuzzy set theory. This framework allows a single “figure-of-merit” to be reported which summarises the results of a complex experiment by image pair, by label or overall. A complementary measure of error, the overlap distance, is defined which captures the spatial extent of the nonoverlapping part and is related to the Hausdorff distance computed on grey level images. The generalized overlap measures are validated on synthetic images for which the overlap can be computed analytically and used as similarity measures in nonrigid registration of three-dimensional magnetic resonance imaging (MRI) brain images. Finally, a pragmatic segmentation ground truth is constructed by registering a magnetic resonance atlas brain to 20 individual scans, and used with the overlap measures to evaluate publicly available brain segmentation algorithms.

图像标记区域的重叠测度，如Dice系数和Tanimoto系数，已被广泛用于评估图像配准和分割算法。现代研究可能包括在多个图像上定义的多个标签，然而大多数评估方案只报告每个标记区域的一个重叠值，简单地平均多个图像。在本文中，常见的重叠测度被推广到测量多个测试图像上定义的标签集合的总重叠，并使用模糊集理论处理分数标签。该框架允许报告单个“品质因数”，它通过图像对、标签或整体来总结复杂实验的结果。定义了一个互补的误差测度——重叠距离，它捕捉了非重叠部分的空间范围，并与在灰度图像上计算的Hausdorff距离相关。广义重叠测度在合成图像上进行了验证，这些图像的重叠可以通过解析计算，并作为三维磁共振成像（MRI）脑图像非刚性配准中的相似性度量。最后，通过将一个磁共振图谱脑配准到20个个体扫描，构建了一个实用的分割金标准，并与重叠测度一起用于评估公开可用的脑分割算法。

Simulations provide a way of generating data where ground truth is known, enabling quantitative testing of image processing methods. In this paper, we present the construction of 20 realistic digital brain phantoms that can be used to simulate medical imaging data. The phantoms are made from 20 normal adults to take into account intersubject anatomical variabilities. Each digital brain phantom was...

模拟提供了一种生成已知真实数据的方法，从而能够定量测试图像处理方法。在本文中，我们介绍了构建20个逼真的数字脑体模，可用于模拟医学成像数据。这些体模由20名正常成年人的数据制作，以考虑受试者间的解剖变异性。每个数字脑体模...

Segmenting cardiac ultrasound images requires a model for the statistics of speckle in the images. Although the statistics of speckle are well understood for the raw transducer signal, the statistics of speckle in the image are not. This paper evaluates simple empirical models for first-order statistics for the distribution of gray levels in speckle. The models are created by analyzing over 100 im...

分割心脏超声图像需要图像中斑点噪声统计的模型。虽然原始换能器信号的斑点噪声统计已被充分理解，但图像中斑点噪声的统计却未知。本文评估了斑点中灰度级分布的一阶统计的简单经验模型。这些模型通过分析超过100幅图像创建...

We have developed a method for automatic contour propagation in cine cardiac magnetic resonance images. The method consists of a new active contour model that tries to maintain a constant contour environment by matching gray values in profiles perpendicular to the contour. Consequently, the contours should maintain a constant position with respect to neighboring anatomical structures, such that th...

我们开发了一种用于心脏电影磁共振图像中自动轮廓传播的方法。该方法包括一个新的主动轮廓模型，该模型通过匹配垂直于轮廓的剖面中的灰度值来尝试维持恒定的轮廓环境。因此，轮廓应相对于相邻解剖结构保持恒定位置，使得...

Validation of image registration algorithms is a difficult task and open-ended problem, usually application-dependent. In this paper, we focus on deep brain stimulation (DBS) targeting for the treatment of movement disorders like Parkinson's disease and essential tremor. DBS involves implantation of an electrode deep inside the brain to electrically stimulate specific areas shutting down the disea...

图像配准算法的验证是一项困难且开放的任务，通常依赖于具体应用。本文聚焦于深部脑刺激（DBS）靶点定位，用于治疗帕金森病和特发性震颤等运动障碍。DBS涉及在大脑深部植入电极，对特定区域进行电刺激，以抑制疾病...

The main goal of this work is the generation of ground-truth data for the validation of atrophy measurement techniques, commonly used in the study of neurodegenerative diseases such as dementia. Several techniques have been used to measure atrophy in cross-sectional and longitudinal studies, but it is extremely difficult to compare their performance since they have been applied to different patien...

这项工作的主要目标是生成用于验证萎缩测量技术的真实数据，这些技术常用于研究神经退行性疾病（如痴呆症）。在横断面和纵向研究中已经使用了多种技术来测量萎缩，但由于它们应用于不同的患者，因此很难比较它们的性能...

This paper presents a nonrigid two-dimensional/three-dimensional (2-D/3-D) registration framework and its phantom validation for subject-specific bronchoscope simulation. The method exploits the recent development of five degrees-of-freedom miniaturized catheter tip electromagnetic trackers such that the position and orientation of the bronchoscope can be accurately determined. This allows the eff...

本文提出了一种非刚性二维/三维（2-D/3-D）配准框架及其用于受试者特异性支气管镜模拟的体模验证。该方法利用最近发展的五自由度微型导管尖端电磁跟踪器，使得支气管镜的位置和方向能够被精确确定。这使得...

Magnetic resonance imaging (MRI) reconstruction techniques are often validated with signal-to-noise ratio (SNR), contrast-to-noise ratio, and mean-to-standard-deviation ratio measured on example images. We present human and model observers as a novel approach to evaluating reconstructions for low-SNR magnetic resonance (MR) images. We measured human and channelized Hotelling observers in a two-alt...

磁共振成像（MRI）重建技术通常通过信噪比（SNR）、对比噪声比和均值标准差比在示例图像上进行验证。我们提出将人类和模型观察者作为评估低SNR磁共振（MR）图像重建的新方法。我们在二选一...

During the process of validation of a new tracer, estimation of performance and validation of processing algorithms have to be investigated with data sets representative of the ground truth. Because this ground truth is hardly accessible in positron emission tomography (PET), validations of processing algorithms often rely on the use of simulated data sets. Considering that Monte Carlo simulators ...

在新示踪剂的验证过程中，需要使用代表真实情况的数据集来评估性能并验证处理算法。由于在正电子发射断层扫描（PET）中很难获得真实情况，因此处理算法的验证通常依赖于模拟数据集。考虑到蒙特卡洛模拟器...

In this paper, three different calibration methods for three-dimensional (3-D) freehand ultrasound (US) are evaluated. Calibration is the process of estimating the rigid transformation from US image coordinates to the coordinate system of the tracking sensor mounted onto the probe. Calibration accuracy has an important impact on quantitative studies. Geometrical precision can also be crucial in ma...

本文评估了三种不同的三维（3-D）自由手超声（US）校准方法。校准是估计从超声图像坐标到安装于探头上的跟踪传感器坐标系的刚性变换的过程。校准精度对定量研究有重要影响。几何精度在...中也至关重要。

This paper presents a new tool for the evaluation of ultrasound image compression. The goal is to measure the image quality as easily as with a statistical criterion, and with the same reliability as the one provided by the medical assessment. An initial experiment is proposed to medical experts and represents our reference value for the comparison of evaluation criteria. Twenty-one statistical cr...

本文介绍了一种用于评估超声图像压缩的新工具。其目标是像统计标准一样容易地测量图像质量，同时具有与医学评估相同的可靠性。向医学专家提出了一个初步实验，它代表了评估标准比较的参考值。二十一项统计标准...

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