11,514 research outputs found
Feature Extraction Using the Hough Transform
This paper contains a brief literature survey of applications and improvements of the Hough transform, a description of the Hough transform and a few of its algorithms, and simulation examples of line and curve detection using the Hough transform
Detection of Airport Runway Edges using Line Detection Techniques
Airport runway detection is a vital aspect for both military and commercial applications. An algorithm to extract runway edges based on edge detection and line detection techniques is discussed. The runway images are initially enhanced by dilation, thresholding and edge detection. Based on some unique characteristics like the runway being gray with two white lines indicating the runway boundaries, long and continuous edges of the runway are considered to be straight lines. The straight lines are detected using Convolution operators pertaining to vertical, 45° or -45° lines. Hough Transform is then applied to fit only the pair of lines corresponding to the runway boundaries in certain orientations. The test results prove that combination of Convolution and Hough transform is very competent in detecting runway edges accurately
New algorithms and technologies for the un-supervised reduction of Optical/IR images
This paper presents some of the main aspects of the software library that has
been developed for the reduction of optical and infrared images, an integral
part of the end-to-end survey system being built to support public imaging
surveys at ESO. Some of the highlights of the new library are: unbiased
estimates of the background, critical for deep IR observations; efficient and
accurate astrometric solutions, using multi-resolution techniques; automatic
identification and masking of satellite tracks; weighted co-addition of images;
creation of optical/IR mosaics, and appropriate management of multi-chip
instruments. These various elements have been integrated into a system using
XML technology for setting input parameters, driving the various processes,
producing comprehensive history logs and storing the results, binding them to
the supporting database and to the web. The system has been extensively tested
using deep images as well as images of crowded fields (e.g. globular clusters,
LMC), processing at a rate of 0.5 Mega-pixels per second using a DS20E ALPHA
computer with two processors. The goal of this presentation is to review some
of the main features of this package.Comment: 12 pages, 9 figures, conferenc
The Hough transform estimator
This article pursues a statistical study of the Hough transform, the
celebrated computer vision algorithm used to detect the presence of lines in a
noisy image. We first study asymptotic properties of the Hough transform
estimator, whose objective is to find the line that ``best'' fits a set of
planar points. In particular, we establish strong consistency and rates of
convergence, and characterize the limiting distribution of the Hough transform
estimator. While the convergence rates are seen to be slower than those found
in some standard regression methods, the Hough transform estimator is shown to
be more robust as measured by its breakdown point. We next study the Hough
transform in the context of the problem of detecting multiple lines. This is
addressed via the framework of excess mass functionals and modality testing.
Throughout, several numerical examples help illustrate various properties of
the estimator. Relations between the Hough transform and more mainstream
statistical paradigms and methods are discussed as well.Comment: Published at http://dx.doi.org/10.1214/009053604000000760 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Timely-automatic procedure for estimating the endocardial limits of the left ventricle assessed echocardiographically in clinical practice
In this paper, we propose an analytical rapid method to estimate the endocardial borders of the left ventricular walls on echocardiographic images for prospective clinical integration. The procedure was created as a diagnostic support tool for the clinician and it is based on the use of the anisotropic generalized Hough transform. Its application is guided by a Gabor-like filtering for the approximate delimitation of the region of interest without the need for computing further anatomical characteristics. The algorithm is applying directly a deformable template on the predetermined filtered region and therefore it is responsive and straightforward implementable. For accuracy considerations, we have employed a support vector machine classifier to determine the confidence level of the automated marking. The clinical tests were performed at the Cardiology Clinic of the County Emergency Hospital Timisoara and they improved the physicians perception in more than 50% of the cases. The report is concluded with medical discussions.European Union (UE)Ministerio de Economía y Competitividad (MINECO). Españ
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