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Papers by Thomas Deschamps

Research paper thumbnail of Extractions de courbes et surfaces par méthodes de chemins minimaux et ensembles de niveaux, applications en imagerie médicale 3D

Research paper thumbnail of Medical imaging station with a function of extracting a path within a ramified object

Research paper thumbnail of System and method to generate an illustration of a cardiac region of interest

Research paper thumbnail of Method to detect the aortic arch in CT datasets for defining a heart window

Research paper thumbnail of Image processing method, system and apparatus for processing an image representing tubular structure and for constructing a path related to said structure

Research paper thumbnail of Automatic construction of minimal paths in 3D images for virtual endoscopy

Cars, 1999

Manual path definition for guiding virtual endoscopy is a very tedious task for human operators. ... more Manual path definition for guiding virtual endoscopy is a very tedious task for human operators. In this paper we present a 3D path tracking routine to build trajectories inside tubular anatomical objects with minimal user interaction. The algorithm determines the "shortest" path between two user indicated points (start and end points).

Research paper thumbnail of Fast extraction of minimal paths in 3D images and applications to virtual endoscopy

The aim of this article is to build trajectories for virtual endoscopy inside 3D medical images, ... more The aim of this article is to build trajectories for virtual endoscopy inside 3D medical images, using the most automatic way. Usually the construction of this trajectory is left to the clinician who must define some points on the path manually using three orthogonal views. But for a complex structure such as the colon, those views give little information on the shape of the object of interest. The path construction in 3D images becomes a very tedious task and precise a priori knowledge of the structure is needed to determine a suitable trajectory. We propose a more automatic path tracking method to overcome those drawbacks: we are able to build a path, given only one or two end points and the 3D image as inputs. This work is based on previous work by Cohen and Kimmel [Int. J. Comp. Vis. 24 (1) (1997) 57] for extracting paths in 2D images using Fast Marching algorithm.

Research paper thumbnail of Scalable Compression Of 3D Medicaldatasets Usinga (2D+T) Wavelet Video Coding Scheme

Abstract Nowadays the all-digital solution in hospitals is becoming widespread. The formidable in... more Abstract Nowadays the all-digital solution in hospitals is becoming widespread. The formidable increase of medical data to be processed, transmitted and stored, requires some efficient compression systems and innovative tools to improve data access, while ensuring ...

Research paper thumbnail of Medical imaging apparatus using fast image segmentation

Research paper thumbnail of Fast evolution of image manifolds and application to filtering andsegmentation in 3D medical images

In many instances, numerical integration of space-scale PDEs is the most time consuming operation... more In many instances, numerical integration of space-scale PDEs is the most time consuming operation of image processing. This is because the scale step is limited by conditional stability of explicit schemes. In this work, we introduce the unconditionally stable semi-implicit linearized difference scheme that is fashioned after additive operator split (AOS) [1], for Beltrami and the subjective surface computation. The Beltrami flow [3], [4], [5] is one of the most effective denoising algorithms in image processing. For gray-level images, we show that the flow equation can be arranged in an advection-diffusion form, revealing the edge-enhancing properties of this flow. This also suggests the application of AOS method for faster convergence. The subjective surface [6] deals with constructing a perceptually meaningful interpretation from partial image data by mimicking the human visual system. However, initialization of the surface is critical for the final result and its main drawbacks are very slow convergence and the huge number of iterations required. In this paper, we first show that the governing equation for the subjective surface flow can be rearranged in an AOS implementation, providing a near real-time solution to the shape completion problem in 2D and 3D. Then, we devise a new initialization paradigm where we first "condition" the viewpoint surface using the Fast-Marching algorithm. We compare the original method with our new algorithm on several examples of real 3D medical images, thus revealing the improvement achieved.

Research paper thumbnail of Segmentation of 3D tubular objects with adaptive front propagation and minimal tree extraction for 3D medical imaging

Computer Methods in Biomechanics and Biomedical Engineering, Aug 1, 2007

We present a new fast approach for segmentation of thin branching structures, like vascular trees... more We present a new fast approach for segmentation of thin branching structures, like vascular trees, based on Fast-Marching (FM) and Level Set (LS) methods. FM allows segmentation of tubular structures by inflating a "long balloon" from a user given single point. However, when the tubular shape is rather long, the front propagation may blow up through the boundary of the desired shape close to the starting point. Our contribution is focused on a method to propagate only the useful part of the front while freezing the rest of it. We demonstrate its ability to segment quickly and accurately tubular and tree-like structures. We also develop a useful stopping criterion for the causal front propagation. We finally derive an efficient algorithm for extracting an underlying 1D skeleton of the branching objects, with minimal path techniques. Each branch being represented by its centerline, we automatically detect the bifurcations, leading to the "Minimal Tree" representation. This so-called "Minimal Tree" is very useful for visualization and quantification of the pathologies in our anatomical data sets. We illustrate our algorithms by applying it to several arteries datasets.

Research paper thumbnail of Method, System and Apparatus for Processing an Image Representing a Tubular Structure and for Constructing a Path Through Said Structure

Research paper thumbnail of Fast Surface and Tree Structure Extraction of Vascular Objects in 3D Medical Images

Abstract: We present a new fast approach for surface segmentation of thin structures, like vessel... more Abstract: We present a new fast approach for surface segmentation of thin structures, like vessels and vascular trees, based on FastMarching and Level Set methods. Fast-Marching allows segmenta-tion of tubular structures inflating a" long balloon" from a user-given ...

Research paper thumbnail of Adaptation of Energy Function in Real-Time Contour Computation for Image Segmentation

Research paper thumbnail of Curve and shape extraction with minimal path and level sets techniques

Research paper thumbnail of Medical imaging station with rapid image segmentation

Research paper thumbnail of Scalable compression of 3D medical datasets using a (2D+T) wavelet video coding scheme

Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467), 2001

Nowadays the all digital solution in hospitals is becoming widespread. The formidable increase of... more Nowadays the all digital solution in hospitals is becoming widespread. The formidable increase of medical data amount to be processed, transmitted and stored, requires some efficient compression systems and innovative tools to improve data access, while ensuring a sufficient visualization quality for diagnosis. Medical image sequences can benefit from advanced video coding techniques when adapted to their specific constraints. Scalability, or the capability to partly decode a video bitstream and to get a reconstruction quality proportional to the decoded amount of information, is a key functionality.

Research paper thumbnail of Adaptation of potential terms in real-time optimal path extraction

![Research paper thumbnail of Groupement de composantes connexes ` a l'aide de chemins minimaux Grouping connected components using minimal path techniques](https://attachments.academia-assets.com/54272249/thumbnails/1.jpg)

We address the problem of finding a set of contour curves in a 2D or 3D image. We consider the pr... more We address the problem of finding a set of contour curves in a 2D or 3D image. We consider the problem of percep- tual grouping and contour completion, where the data is an unstructured set of regions in the image. A new method to find complete curves from a set of edge points is presen- ted. Contours are found as

Research paper thumbnail of Air-flow simulation in realistic models of the trachea

The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2004

In this article we present preliminary results from a new technique for flow simulation in realis... more In this article we present preliminary results from a new technique for flow simulation in realistic anatomical airways. The airways are extracted by means of Level-Sets methods that accurately model the complex and varying surfaces of anatomical objects. The surfaces obtained are defined at the sub-pixel level where they intersect the Cartesian grid of the image domain. It is therefore straightforward to construct embedded boundary representations of these objects on the same grid, for which recent work has enabled discretization of the Navier-Stokes equations for incompressible fluids. While most classical techniques require construction of a structured mesh that approximates the surface in order to extrapolate a 3D finite-element griding of the whole volume, our method directly simulates the air-flow inside the extracted surface without losing any complicated details and without building additional grids.

Research paper thumbnail of Extractions de courbes et surfaces par méthodes de chemins minimaux et ensembles de niveaux, applications en imagerie médicale 3D

Research paper thumbnail of Medical imaging station with a function of extracting a path within a ramified object

Research paper thumbnail of System and method to generate an illustration of a cardiac region of interest

Research paper thumbnail of Method to detect the aortic arch in CT datasets for defining a heart window

Research paper thumbnail of Image processing method, system and apparatus for processing an image representing tubular structure and for constructing a path related to said structure

Research paper thumbnail of Automatic construction of minimal paths in 3D images for virtual endoscopy

Cars, 1999

Manual path definition for guiding virtual endoscopy is a very tedious task for human operators. ... more Manual path definition for guiding virtual endoscopy is a very tedious task for human operators. In this paper we present a 3D path tracking routine to build trajectories inside tubular anatomical objects with minimal user interaction. The algorithm determines the "shortest" path between two user indicated points (start and end points).

Research paper thumbnail of Fast extraction of minimal paths in 3D images and applications to virtual endoscopy

The aim of this article is to build trajectories for virtual endoscopy inside 3D medical images, ... more The aim of this article is to build trajectories for virtual endoscopy inside 3D medical images, using the most automatic way. Usually the construction of this trajectory is left to the clinician who must define some points on the path manually using three orthogonal views. But for a complex structure such as the colon, those views give little information on the shape of the object of interest. The path construction in 3D images becomes a very tedious task and precise a priori knowledge of the structure is needed to determine a suitable trajectory. We propose a more automatic path tracking method to overcome those drawbacks: we are able to build a path, given only one or two end points and the 3D image as inputs. This work is based on previous work by Cohen and Kimmel [Int. J. Comp. Vis. 24 (1) (1997) 57] for extracting paths in 2D images using Fast Marching algorithm.

Research paper thumbnail of Scalable Compression Of 3D Medicaldatasets Usinga (2D+T) Wavelet Video Coding Scheme

Abstract Nowadays the all-digital solution in hospitals is becoming widespread. The formidable in... more Abstract Nowadays the all-digital solution in hospitals is becoming widespread. The formidable increase of medical data to be processed, transmitted and stored, requires some efficient compression systems and innovative tools to improve data access, while ensuring ...

Research paper thumbnail of Medical imaging apparatus using fast image segmentation

Research paper thumbnail of Fast evolution of image manifolds and application to filtering andsegmentation in 3D medical images

In many instances, numerical integration of space-scale PDEs is the most time consuming operation... more In many instances, numerical integration of space-scale PDEs is the most time consuming operation of image processing. This is because the scale step is limited by conditional stability of explicit schemes. In this work, we introduce the unconditionally stable semi-implicit linearized difference scheme that is fashioned after additive operator split (AOS) [1], for Beltrami and the subjective surface computation. The Beltrami flow [3], [4], [5] is one of the most effective denoising algorithms in image processing. For gray-level images, we show that the flow equation can be arranged in an advection-diffusion form, revealing the edge-enhancing properties of this flow. This also suggests the application of AOS method for faster convergence. The subjective surface [6] deals with constructing a perceptually meaningful interpretation from partial image data by mimicking the human visual system. However, initialization of the surface is critical for the final result and its main drawbacks are very slow convergence and the huge number of iterations required. In this paper, we first show that the governing equation for the subjective surface flow can be rearranged in an AOS implementation, providing a near real-time solution to the shape completion problem in 2D and 3D. Then, we devise a new initialization paradigm where we first "condition" the viewpoint surface using the Fast-Marching algorithm. We compare the original method with our new algorithm on several examples of real 3D medical images, thus revealing the improvement achieved.

Research paper thumbnail of Segmentation of 3D tubular objects with adaptive front propagation and minimal tree extraction for 3D medical imaging

Computer Methods in Biomechanics and Biomedical Engineering, Aug 1, 2007

We present a new fast approach for segmentation of thin branching structures, like vascular trees... more We present a new fast approach for segmentation of thin branching structures, like vascular trees, based on Fast-Marching (FM) and Level Set (LS) methods. FM allows segmentation of tubular structures by inflating a "long balloon" from a user given single point. However, when the tubular shape is rather long, the front propagation may blow up through the boundary of the desired shape close to the starting point. Our contribution is focused on a method to propagate only the useful part of the front while freezing the rest of it. We demonstrate its ability to segment quickly and accurately tubular and tree-like structures. We also develop a useful stopping criterion for the causal front propagation. We finally derive an efficient algorithm for extracting an underlying 1D skeleton of the branching objects, with minimal path techniques. Each branch being represented by its centerline, we automatically detect the bifurcations, leading to the "Minimal Tree" representation. This so-called "Minimal Tree" is very useful for visualization and quantification of the pathologies in our anatomical data sets. We illustrate our algorithms by applying it to several arteries datasets.

Research paper thumbnail of Method, System and Apparatus for Processing an Image Representing a Tubular Structure and for Constructing a Path Through Said Structure

Research paper thumbnail of Fast Surface and Tree Structure Extraction of Vascular Objects in 3D Medical Images

Abstract: We present a new fast approach for surface segmentation of thin structures, like vessel... more Abstract: We present a new fast approach for surface segmentation of thin structures, like vessels and vascular trees, based on FastMarching and Level Set methods. Fast-Marching allows segmenta-tion of tubular structures inflating a" long balloon" from a user-given ...

Research paper thumbnail of Adaptation of Energy Function in Real-Time Contour Computation for Image Segmentation

Research paper thumbnail of Curve and shape extraction with minimal path and level sets techniques

Research paper thumbnail of Medical imaging station with rapid image segmentation

Research paper thumbnail of Scalable compression of 3D medical datasets using a (2D+T) wavelet video coding scheme

Proceedings of the Sixth International Symposium on Signal Processing and its Applications (Cat.No.01EX467), 2001

Nowadays the all digital solution in hospitals is becoming widespread. The formidable increase of... more Nowadays the all digital solution in hospitals is becoming widespread. The formidable increase of medical data amount to be processed, transmitted and stored, requires some efficient compression systems and innovative tools to improve data access, while ensuring a sufficient visualization quality for diagnosis. Medical image sequences can benefit from advanced video coding techniques when adapted to their specific constraints. Scalability, or the capability to partly decode a video bitstream and to get a reconstruction quality proportional to the decoded amount of information, is a key functionality.

Research paper thumbnail of Adaptation of potential terms in real-time optimal path extraction

![Research paper thumbnail of Groupement de composantes connexes ` a l'aide de chemins minimaux Grouping connected components using minimal path techniques](https://attachments.academia-assets.com/54272249/thumbnails/1.jpg)

We address the problem of finding a set of contour curves in a 2D or 3D image. We consider the pr... more We address the problem of finding a set of contour curves in a 2D or 3D image. We consider the problem of percep- tual grouping and contour completion, where the data is an unstructured set of regions in the image. A new method to find complete curves from a set of edge points is presen- ted. Contours are found as

Research paper thumbnail of Air-flow simulation in realistic models of the trachea

The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2004

In this article we present preliminary results from a new technique for flow simulation in realis... more In this article we present preliminary results from a new technique for flow simulation in realistic anatomical airways. The airways are extracted by means of Level-Sets methods that accurately model the complex and varying surfaces of anatomical objects. The surfaces obtained are defined at the sub-pixel level where they intersect the Cartesian grid of the image domain. It is therefore straightforward to construct embedded boundary representations of these objects on the same grid, for which recent work has enabled discretization of the Navier-Stokes equations for incompressible fluids. While most classical techniques require construction of a structured mesh that approximates the surface in order to extrapolate a 3D finite-element griding of the whole volume, our method directly simulates the air-flow inside the extracted surface without losing any complicated details and without building additional grids.