https://www.cs.ucla.edu/~dt/papers/mia96/mia96.pdf

Deformable models in medical image analysis: a survey

In recent years, many shape representations and geometric algorithms have been proposed for matching 3D shapes. Usually, each algorithm is tested on a different (small) database of 3D models, and thus no direct comparison is available for competing methods. We describe the Princeton Shape Benchmark (PSB), a publicly available database of polygonal models collected from the World Wide Web and a suite of tools for comparing shape matching and classification algorithms. One feature of the benchmark is that it provides multiple semantic labels for each 3D model. For instance, it includes one classification of the 3D models based on function, another that considers function and form, and others based on how the object was constructed (e.g., man-made versus natural objects). We find that experiments with these classifications can expose different properties of shape-based retrieval algorithms. For example, out of 12 shape descriptors tested, extended Gaussian images by B. Horn (1984) performed best for distinguishing man-made from natural objects, while they performed among the worst for distinguishing specific object types. Based on experiments with several different shape descriptors, we conclude that no single descriptor is best for all classifications, and thus the main contribution of this paper is to provide a framework to determine the conditions under which each descriptor performs best.

/pdf/the-princeton-shape-benchmark-2gmwi9i096.pdf

The Princeton Shape Benchmark

BackgroundLung auscultation and bedside chest radiography are routinely used to assess the respiratory condition of ventilated patients with acute respiratory distress syndrome (ARDS). Clinical experience suggests that the diagnostic accuracy of these procedures is poor.MethodsThis prospective study

Comparative Diagnostic Performances of Auscultation, Chest Radiography, and Lung Ultrasonography in Acute Respiratory Distress Syndrome

Recent developments in techniques for modeling, digitizing and visualizing 3D shapes has led to an explosion in the number of available 3D models on the Internet and in domain-specific databases. This has led to the development of 3D shape retrieval systems that, given a query object, retrieve similar 3D objects. For visualization, 3D shapes are often represented as a surface, in particular polygonal meshes, for example in VRML format. Often these models contain holes, intersecting polygons, are not manifold, and do not enclose a volume unambiguously. On the contrary, 3D volume models, such as solid models produced by CAD systems, or voxels models, enclose a volume properly. This paper surveys the literature on methods for content based 3D retrieval, taking into account the applicability to surface models as well as to volume models. The methods are evaluated with respect to several requirements of content based 3D shape retrieval, such as: (1) shape representation requirements, (2) properties of dissimilarity measures, (3) efficiency, (4) discrimination abilities, (5) ability to perform partial matching, (6) robustness, and (7) necessity of pose normalization. Finally, the advantages and limitations of the several approaches in content based 3D shape retrieval are discussed.

/pdf/a-survey-of-content-based-3d-shape-retrieval-methods-1p1e9hurpn.pdf

A survey of content based 3D shape retrieval methods

The American Thoracic Society/European Respiratory Society jointly created a Task Force on "Outcomes for COPD pharmacological trials: from lung function to biomarkers" to inform the chronic obstructive pulmonary disease research community about the possible use and limitations of current outcomes and markers when evaluating the impact of a pharmacological therapy. Based on their review of the published literature, the following document has been prepared with individual sections that address specific outcomes and markers, and a final section that summarises their recommendations.

/pdf/outcomes-for-copd-pharmacological-trials-from-lung-function-4a4k924y7q.pdf

Outcomes for COPD pharmacological trials: From lung function to biomarkers

The paper presents the French RIMES (Reconnaissance et Indexation de donnees Manuscrites et de fac similES / Recognition and Indexing of handwritten documents and faxes) project, which is an evaluation campaign dedicated to automatic systems of recognition and indexing of handwritten letters such as those sent by postal mail or fax by individuals to companies or administrations. This project is intended to all the key players of the handwritten recognition and document analysis fields by proposing them to participate to evaluation tests, a first test having taken already place. In this framework, a new database of more than 5600 real mails completely annotated have been created as well as secondary databases of isolated characters, handwritten words (300 000 snippets) and logos. Beyond the evaluation, the other contribution of the RIMES project is to make available all these databases to the community after the last test

RIMES evaluation campaign for handwritten mail processing

Combining helical volumetric CT acquisition and thin-slice thickness during breath hold provides an accurate assessment of both focal and diffuse airway diseases. With multiple detector rows, compared with single-slice helical CT, multislice CT can cover a greater volume, during a simple breath hold, and with better longitudinal and in-plane spatial resolution and improved temporal resolution. The result in data set allows the generation of superior multiplanar and 3D images of the airways, including those obtained from techniques developed specifically for airway imaging, such as virtual bronchography and virtual bronchoscopy. Complementary CT evaluation at suspended or continuous full expiration is mandatory to detect air trapping that is a key finding for depicting an obstruction on the small airways. Indications for CT evaluation of the airways include: (a) detection of endobronchial lesions in patients with an unexplained hemoptysis; (b) evaluation of extent of tracheobronchial stenosis for planning treatment and follow-up; (c) detection of congenital airway anomalies revealed by hemoptysis or recurrent infection; (d) detection of postinfectious or postoperative airway fistula or dehiscence; and (e) diagnosis and assessment of extent of bronchiectasis and small airway disease. Improvement in image analysis technique and the use of spirometrically control of lung volume acquisition have made possible accurate and reproducible quantitative assessment of airway wall and lumen areas and lung density. This contributes to better insights in physiopathology of obstructive lung disease, particularly in chronic obstructive pulmonary disease and asthma.

New frontiers in CT imaging of airway disease.

In the framework of computer-aided diagnosis, this paper proposes a novel functionality for the computerized tomography (CT)-based investigation of the pulmonary airways. It relies on an energy-based three-dimensional (3-D) reconstruction of the bronchial tree from multislice CT acquisitions, up to the sixth- to seventh-order subdivisions. Global and local analysis of the reconstructed airways is possible by means of specific visualization modalities, respectively, the CT bronchography and the virtual bronchoscopy. The originality of the 3-D reconstruction approach consists in combining axial and radial propagation potentials to control the growth of a subset of low-order airways extracted from the CT volume by means of a robust mathematical morphology operator-the selective marking and depth constrained (SMDC) connection cost. The proposed approach proved to be robust with respect to a large spectrum of airway pathologies, including even severe stenosis (bronchial lumen obstruction/collapse). Validated by expert radiologists, examples of airway 3-D reconstructions are presented and discussed for both normal and pathological cases. They highlight the interest in considering CT bronchography and virtual bronchoscopy as complementary tools for clinical diagnosis and follow-up of airway diseases.

Pulmonary airways: 3-D reconstruction from multislice CT and clinical investigation

Because of the continuous development of multimedia technologies, virtual worlds and augmented reality, 3D contents become a common feature of the today information systems. Hence, standardizing tools for content-based indexing of visual data is a key issue for computer vision related applications. Within the framework of the future MPEG-7 standard, tools for intelligent content-based access to 3D information, targeting applications such as search & retrieval and browsing of 3D model databases, have been recently considered and evaluated. In this paper, we present the 3D Shape Spectrum Descriptor (3D SSD), recently adopted within the current MPEG-7 Committee Draft (CD). The proposed descriptor aims at providing an intrinsic shape description of a 3D mesh and is defined as the distribution of the shape index over the entire mesh. The shape index is a local geometric attribute of a 3D surface, expressed as the angular coordinate of a polar representation of the principal curvature vector. Experimental results have been carried out upon the MPEG-7 3D model database consisting of about 1300 meshes in VRML 2.0 format. Objective retrieval results, based upon the definition of a ground truth subset, are reported in terms of Bull Eye Percentage (BEP) score.

3D Shape-based retrieval within the MPEG-7 framework

This paper addresses the issue of 3D mesh indexation by using shape descriptors (SDs) under constraints of geometric and topological invariance. A new shape descriptor, the canonical 3D Hough transform descriptor (C3DHTD) is here proposed. Intrinsically topologically stable, the C3DHTD is not invariant to geometric transformations. Nevertheless, we show mathematically how the C3DHTD can be optimally associated (in terms of compactness of representation and computational complexity) with a spatial alignment procedure which leads to a geometric invariant behavior. Experiments carried out upon the categorized MPEG-7 3D model database objectively show that the C3DHTD outperforms both the MPEG-7 3D SD and classic EGIs descriptor.

Francoise Preteux

Papers

RIMES evaluation campaign for handwritten mail processing

New frontiers in CT imaging of airway disease.

Pulmonary airways: 3-D reconstruction from multislice CT and clinical investigation

3D Shape-based retrieval within the MPEG-7 framework

Shape-based retrieval of 3D mesh models