Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/3883
2016-10-22T21:42:05ZCodificación adaptativa de imágenes mediante la transformada coseno discreta
http://hdl.handle.net/2117/87807
Codificación adaptativa de imágenes mediante la transformada coseno discreta
Torres Urgell, Lluís
2016-06-08T14:49:45ZTorres Urgell, LluísAutomatic left ventricular contour extraction for volume calculation from echocardiographic images
http://hdl.handle.net/2117/87806
Automatic left ventricular contour extraction for volume calculation from echocardiographic images
Gasull Llampallas, Antoni; Torres Urgell, Lluís; Marqués Acosta, Fernando; Vázquez Grau, Gregorio
This paper presents a new fully automated algorithm that extracts LV epicardial and endocardial borders from 2-D echocardiograms. The method is based on a radial search approach, which is the best way to use some a priori informations of the edges. A signature descriptor of contours is carried out. From that function and using Fourier series for extrapolation and tracking in some steps a good approach of edges is found. an extension of this algorithm to contour searching on a sequence of 2-D echograms covering the entire cardiac cycle is easily performed. From this approach over apical rotatied views a cylindrical integration method is used for estimating the left ventricular volume.
2016-06-08T14:47:42ZGasull Llampallas, AntoniTorres Urgell, LluísMarqués Acosta, FernandoVázquez Grau, GregorioThis paper presents a new fully automated algorithm that extracts LV epicardial and endocardial borders from 2-D echocardiograms. The method is based on a radial search approach, which is the best way to use some a priori informations of the edges. A signature descriptor of contours is carried out. From that function and using Fourier series for extrapolation and tracking in some steps a good approach of edges is found. an extension of this algorithm to contour searching on a sequence of 2-D echograms covering the entire cardiac cycle is easily performed. From this approach over apical rotatied views a cylindrical integration method is used for estimating the left ventricular volume.Classical methods of left ventricular contour extraction and preprocessing of echocardiographic images: a review
http://hdl.handle.net/2117/87805
Classical methods of left ventricular contour extraction and preprocessing of echocardiographic images: a review
Torres Urgell, Lluís; Gasull Llampallas, Antoni; Marqués Acosta, Fernando
A main objective of digital processing of echocardiographic images is to improve the signal to noise ratio of the video images acquired from the ultrasound equipment along with contour extraction in order to obtain cardiac parameters. We present a review and comparison among the different proposed methods in the current literature for both noise removal and contour extraction of echocardiographic images. It is shown that classical methods do not render good contours and there is a need for a different approach to contour extraction algorithms.
2016-06-08T14:46:04ZTorres Urgell, LluísGasull Llampallas, AntoniMarqués Acosta, FernandoA main objective of digital processing of echocardiographic images is to improve the signal to noise ratio of the video images acquired from the ultrasound equipment along with contour extraction in order to obtain cardiac parameters. We present a review and comparison among the different proposed methods in the current literature for both noise removal and contour extraction of echocardiographic images. It is shown that classical methods do not render good contours and there is a need for a different approach to contour extraction algorithms.Three dimensional adaptive Laplacian Pyramid image coding
http://hdl.handle.net/2117/84991
Three dimensional adaptive Laplacian Pyramid image coding
Sallent Ribes, Sebastián; Torres Urgell, Lluís; Gils, L.
2016-03-31T13:56:46ZSallent Ribes, SebastiánTorres Urgell, LluísGils, L.Vector quantization in image sequence coding
http://hdl.handle.net/2117/84987
Vector quantization in image sequence coding
Huguet, Jordi; Torres Urgell, Lluís
2016-03-31T13:40:20ZHuguet, JordiTorres Urgell, LluísTemporal automatic edge detection of echocardiographic images
http://hdl.handle.net/2117/84722
Temporal automatic edge detection of echocardiographic images
Torres Urgell, Lluís; Gasull Llampallas, Antoni
2016-03-18T15:21:50ZTorres Urgell, LluísGasull Llampallas, AntoniObtencion de un esqueleto morfologico sin puntos redundantes
http://hdl.handle.net/2117/84338
Obtencion de un esqueleto morfologico sin puntos redundantes
Marqués Acosta, Fernando; Gasull Llampallas, Antoni; Torres Urgell, Lluís
Skeleton is a powerful method to describe binary images. Although there are different possibilities to define a skeleton, is very common to use morphological skeleton because it is easy and fast for implementation purposes. However, the set of points representing a morphological skeleton is redundant. This paper describes a method for selecting the mínimum number of points that have to be kept in order to reconstruct the binary image. Sorne results show that more than 50% of points can be saved.
2016-03-14T16:17:18ZMarqués Acosta, FernandoGasull Llampallas, AntoniTorres Urgell, LluísSkeleton is a powerful method to describe binary images. Although there are different possibilities to define a skeleton, is very common to use morphological skeleton because it is easy and fast for implementation purposes. However, the set of points representing a morphological skeleton is redundant. This paper describes a method for selecting the mínimum number of points that have to be kept in order to reconstruct the binary image. Sorne results show that more than 50% of points can be saved.Análisis de no estacionariedades en la interpolación de imágenes. Aplicación a codificación piramidal y zoom
http://hdl.handle.net/2117/84072
Análisis de no estacionariedades en la interpolación de imágenes. Aplicación a codificación piramidal y zoom
Gasull Llampallas, Antoni; Marqués Acosta, Fernando; Torres Urgell, Lluís
In some applications of digital image processing the fact that an image is a non estacionary signal can cause some undesirable effects. That is the case of block effect in transform coding, or destructive effects on contours in interpolation or decimation images. This paper deals with interpolation image case carried out by a previous segmentation of the image in estacionary regions, which can be interpolated in a classical way. The results have been applicated for zooming purposes, and in multirresolution image decomposition in order to reduce the error in decimation-interpolation process.
2016-03-09T15:05:03ZGasull Llampallas, AntoniMarqués Acosta, FernandoTorres Urgell, LluísIn some applications of digital image processing the fact that an image is a non estacionary signal can cause some undesirable effects. That is the case of block effect in transform coding, or destructive effects on contours in interpolation or decimation images. This paper deals with interpolation image case carried out by a previous segmentation of the image in estacionary regions, which can be interpolated in a classical way. The results have been applicated for zooming purposes, and in multirresolution image decomposition in order to reduce the error in decimation-interpolation process.An adaptive pyramid image coding system
http://hdl.handle.net/2117/83908
An adaptive pyramid image coding system
Torres Urgell, Lluís; Sallent Ribes, Sebastián
The Laplacian Pyramid is a new and efficient method for image encoding. The method is of increasing interest as band-pass pyramids and multiresolution images are being used in other image processing applications. The Pyramid Coding system is a hierarchical structure well suited for progressive image transmission over low-speed channels and hierarchical image retrieving in com- puterized image storage. The goal if this paper is to present a new pyramidal image structure that uses algorithms defined on arbitrary non-rectangular sampling lattices. An adaptive technique is also developed that assigns to the pyramidal structure an optimum sampling lattice as a function of the frequency content of the original image.
2016-03-07T16:29:12ZTorres Urgell, LluísSallent Ribes, SebastiánThe Laplacian Pyramid is a new and efficient method for image encoding. The method is of increasing interest as band-pass pyramids and multiresolution images are being used in other image processing applications. The Pyramid Coding system is a hierarchical structure well suited for progressive image transmission over low-speed channels and hierarchical image retrieving in com- puterized image storage. The goal if this paper is to present a new pyramidal image structure that uses algorithms defined on arbitrary non-rectangular sampling lattices. An adaptive technique is also developed that assigns to the pyramidal structure an optimum sampling lattice as a function of the frequency content of the original image.Diseño de filtros de imagen con funciones de transferencia de dominio romboidal
http://hdl.handle.net/2117/83820
Diseño de filtros de imagen con funciones de transferencia de dominio romboidal
Casas Rius, Joan Ramon; Torres Urgell, Lluís
When orthogonal sampllng patterns are applled to digitize analogue images, some degree of spatial redundancy is lntroduced. Quincunx sampllng patterns allow to remove this redundant visual lnformation which consist of diagonal image frequencies. Such processing ls usually done in the HD-MAC coding system for HDTV lmages. In this paper we suggest one method to design the 20-decimation fllters needed in quincunx subsampiing processes. The advantages of the design based on frequency domaln analysis are also pointed out. Finally, we show the performance of one of this filters.
2016-03-04T12:55:01ZCasas Rius, Joan RamonTorres Urgell, LluísWhen orthogonal sampllng patterns are applled to digitize analogue images, some degree of spatial redundancy is lntroduced. Quincunx sampllng patterns allow to remove this redundant visual lnformation which consist of diagonal image frequencies. Such processing ls usually done in the HD-MAC coding system for HDTV lmages. In this paper we suggest one method to design the 20-decimation fllters needed in quincunx subsampiing processes. The advantages of the design based on frequency domaln analysis are also pointed out. Finally, we show the performance of one of this filters.